Design News April 2009 by Praveen Kumar Deepak Velayudhan

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FLASH: TRIMMING POWER USE

Designs curtail consumption, p20 SHERLOCK OHMS INVESTIGATES Real-world mysteries solved, p22 GM’S CHOICE FOR VOLT BATTERY ‘Stack-and-fold’ shape is key, p31

APRIL 2009 $15.00

ACCELERATING ENGINEERING INNOVATION www.designnews.com 2008

Plus NPE 2009: NEW PLASTICS CUT PART WEIGHT, ENERGY USAGE, p55

HAMSTER POWER:

Nanogenerators Produce Electricity FROM

Running Rodents IRREGULAR MECHANICAL MOTIONS COULD BE CONVERTED TO USABLE ENERGY, p50

The Truth About Compressed Air! If you think compressed air is too expensive and noisy - read this. The facts will surprise you!

Compare these Blowoffs

Facts about Blowers

There are a variety of ways to blow the water from the bottles shown in the photo below, but which method is best? To decide, we ran a comparison test on the same application using four different blowoff methods: drilled pipe, flat air nozzles, Super Air Knife (each using compressed air as a power source), and a blower supplied air knife (using an electric motor as a power source). Each system consisted of two twelve inch long air knives. The following comparison proves that the EXAIR Super Air Knife is the best choice for your blowoff, cooling or drying application.

Energy conscious plants might think a blower to be a better choice due to its slightly lower electrical consumption compared to a compressor. In reality, a blower is an expensive capital expenditure that requires frequent downtime and costly maintenance of ﬁlters, belts and bearings.

The goal for each of the blowoff choices was to use the least amount of air possible to get the job done (lowest energy and noise level). The compressed air pressure required was 60 PSIG which provided adequate velocity to blow the water off. The blower used had a ten horsepower motor and was a centrifugal type blower at 18,000 RPM. The table at the bottom of the page summarizes the overall performance. Since your actual part may have an odd configuration, holes or sharp edges, we took sound level measurements in free air (no impinging surface).

Here are some important facts: Filters must be replaced every one to three months. Belts must be replaced every three to six months. Typical bearing replacement is at least once a year at a cost near $1000.

Drilled Pipe

Blower Air Knife

This common blowoﬀ is very inexpensive and easy to make. For this test, we used (2) drilled pipes, each with (25) 1/16" diameter holes on 1/2" centers. As shown in the test results below, the drilled pipe performed poorly. The initial cost of the drilled pipe is overshadowed by its high energy use. The holes are easily blocked and the noise level is excessive - both of which violate OSHA requirements. Velocity across the entire length was very inconsistent with spikes of air and numerous dead spots.

The blower proved to be an expensive, noisy option. As noted below, the purchase price is high. Operating cost was considerably lower than the drilled pipe and flat air nozzle, but was comparable to EXAIR’s Super Air Knife. The large blower with its two 3" (8cm) diameter hoses requires significant mounting space compared to the others. Noise level was high at 90 dBA. There was no option for cycling it on and off to conserve energy like the other blowoffs. Costly bearing and filter maintenance along with downtime were also negative factors.

Flat Air Nozzles

EXAIR Super Air Knife

As shown below, this inexpensive air nozzle was the worst performer. It is available in plastic, aluminum and stainless steel from several manufacturers. The flat air nozzle provides some entrainment, but suffers from many of the same problems as the drilled pipe. Operating cost and noise level are both high. Some manufacturers offer flat air nozzles where the holes can be blocked - an OSHA violation. Velocity was inconsistent with spikes of air.

The Super Air Knife did an exceptional job of removing the moisture on one pass due to the uniformity of the laminar airﬂow. The sound level was extremely low. For this application, energy use was slightly higher than the blower but can be less than the blower if cycling on and oﬀ is possible. Safe operation is not an issue since the Super Air Knife can not be dead-ended. Maintenance costs are low since there are no moving parts to wear out.

• Blower bearings wear out quickly due to the high speeds (17-20,000 RPM) required to generate effective airflows. • Poorly designed seals that allow dirt and moisture infiltration and environments above 125°F decrease the one year bearing life. • Many bearings can not be replaced in the field, resulting in downtime to send the assembly back to the manufacturer. Blowers take up a lot of space and often produce sound levels that exceed OSHA noise level exposure requirements. Air volume and velocity are often difficult to control since mechanical adjustments are required. To discuss an application, contact:

EXAIR Corporation

11510 Goldcoast Drive Cincinnati, Ohio 45249-1621 (800) 903-9247 Fax: (513) 671-3363 email: techelp@exair.com www.exair.com/14/423.htm

The Super Air Knife is the low cost way to blowoff, dry, clean and cool.

Blowoff Comparison Comp. Air Type of blowoff

PSIG BAR

SCFM

SLPM

Horsepower Sound Purchase Required Level dBA Price

Annual Approx. Annual First Year Electrical Cost Maintenance Cost Cost*

Drilled Pipes

4.1

174

4,924

$50

$4,508

$920

$5,478

Flat Air Nozzles

4.1

257

7,273

102

$168

$6,569

$1,450

$8,187

Blower Air Knife

0.2

N/A

$5,500

$1,288

$1,500

$8,288

Super Air Knife

4.1

1,557

$480

$1,417

$300

$2,197

*Based on national average electricity cost of 8.3 cents per kWh. Annual cost reflects 40 hours per week, 52 weeks per year.

ACCELERATING ENGINEERING INNOVATION www.designnews.com

contents April 2009 volume 64 no. 04

Features COVER STORY

50 The Dawn of NanoEnergy A hamster running on a wheel, fingers tapping on a table or a flag waving in the breeze are some of the ways researchers are hoping to harvest usable energy. BY CHARLES J. MURRAY, Senior Technical Editor, Electronics

Departments

10 POST OFFICE DN’s most popular blog posts

RANT

14 Recession Equals Inspiration

16 MECHATRONICS

Despite the economic downturn, innovation will not be stifled. BY JEFF RAY, CEO, Concord, MA-Based DS SolidWorks Corp. SHERLOCK OHMS

22 The Adventure of the Incredible Sparking Car What caused a very high-voltage arcing spark in the engine of a car that was only running on a 12-V system? BY ARTHUR SUNDEEN, Contributing Writer

55 Get an Edge with Nitrogen Foam This year’s National Plastic’s Exposition is going green, highlighting the latest plastics technologies that will help improve the environment. BY DOUG SMOCK, Contributing Editor, Materials and Fastening THE FIELD REPORT

9 Design Engineering Detectives Check out DN’s newest feature — Sherlock Ohms, a tribute to engineering’s most diabolical real-world investigations. BY KAREN AUGUSTON FIELD, Editor-in-Chief MAIL

12 Readers Sound off DN readers agree with the “Top 5 Reasons to Stop Whining.” COVER IMAGE: CHUCK MACKEY

20 FLASH New and Noteworthy Products

26 TIPS FROM TITUS Unbelievably Useful Information from a Test Expert

31 NEWS Trends, Developments, Breakthroughs

46 TREND WATCH

AT S TA K E F E AT U R E

Fresh ideas on integrating mechanical systems, electronics, control systems and software.

Stuff You Need to Know

28 They Said What? A new survey reveals what Americans really think about engineering. BY GEOFFREY C. ORSAK, Dean of Engineering, Southern Methodist University

59 EXPO Best of the Engineering Marketplace ANALOG/POWER MANAGEMENT

Find this section between pages 68 and 74.

CALAMITIES

74 The Case of the Spurious Spring A young man was seriously injured after a replacement part on his motorcycle failed. BY KENNETH RUSSELL, Contributing Editor GADGET FREAK

FLUID POWER/POWER TRANSMISSION Look for this special section between pages 48 and 49. If your copy of Design News does not include this section, you can view it at http://designnews.hotims.com/23101-500. DESIGN NEWS SUPPLEMENT THE CONVERGENCE O F M U LT I D I S C I P L I N E CONTROL

76 Power Blender is Sweetly Green Rick Crammond’s turbine blender is inspired by Nikola Tesla and makes a frosty drink in the blink of an eye.

Engineers are looking for single platforms to handle motion, logic and HMI tasks. This special supplement features articles showing PACs in action, examples of how they offer advantages over other control platform solutions and a Q&A from an industry expert on the factors driving this trend.

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An indoor/outdoor thermometer with hygrometer from RadioShack displays temperature to one tenth of a degree. Check out why that fact is pointless. If you find a product that was made by monkeys, e-mail Editor-in-Chief Karen Field at kfield@reedbusiness.com. http://designnews.hotims.com/23101-503

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See what DN’s newest blogger Joel Young has to say, as he takes a look at the world of wireless — electronics on airplanes, microwave ovens, Wi-Fi and many other topics. http://designnews.hotims.com/23101-502

New Blog: The Weird and Wonderful World of Wireless

3-D Modeling Debate Spurs New Generation of CAD Tools A new generation of hybrid CAD tools is combining the power and control of history-based offerings with the flexibility and ease-of-use of direct modelers. Here’s a look at how this new breed of CAD is opening up the technology to new users. http://designnews.hotims.com/23101-504 Webcast: A Fork in the Road in 3-D CAD Modeling A panel of leading CAD experts weigh in on the direct modeling versus history-based CAD debate. Tune in to discover where each modeling method works best and how to make both types of tools coexist successfully in your development organization. http://designnews.hotims.com/23101-505

FREE WEBCAST: THE WORLD IS FLAT — EXCEPT IN DYNAMICS Listen to Kevin C. Craig, Ph.D., Robert C. Greenheck Chair in Engineering Design and professor of Mechanical Engineering at Marquette University, discuss why 3-D dynamics is important in mechatronic system design and how tools like ADAMS make it easier to understand and explain difficult dynamic concepts. www.mechatronicszone.com N FE DE

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HAVE YOU BUILT A BETTER MOUSETRAP? Let us know! Tell us about the most amazing product you designed in 2008 and it could be profiled, along with other great new products, in Design News’ Special Engineering Awards issue in September. When you submit your entry form and payment no later than May 15, we’ll make sure your entry makes it into the hands of our judges — Design News’ editors. Enter today at: www.designnews.com/mousetrap

Online Resource Center

Selector Guide Green Pressure Sensing Option for Emissions Control from Kavlico Newly enacted regulations require exhaust gas monitoring and filtering in diesel engines to remove Particulate Matter, thus minimizing the amount of pollutants pumped into the air people breathe. Discover a full line of green-minded sensors for passenger vehicles using either gas or diesel. http://designnews.hotims.com/23101-507

Reference Guide Understand the Total Cost of Embedded Design from National Instruments When developing an embedded device, deciding which technology to implement as the system’s primary controller is one of the first key engineering milestones. This tutorial outlines two options for developing a new controller and discusses the technical and financial risks associated with both. http://designnews.hotims.com/23101-508

Product Brief Avoid Industrial Hose Hazards — Start Thinking System from Gates Poorly designed, constructed or misapplied industrial transfer hose installations are serious workplace hazards. How can you prevent a potential hose catastrophe? Abandon the common practice of mixing and matching components to fabricate a hose assembly and start thinking system. http://designnews.hotims.com/23101-509

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Detectives HAVING CUT MY TEETH ON PULP DETECTIVE

Have you applied your deductive reasoning and technical prowess to troubleshoot and solve an engineering mystery that even the fictional Sherlock would find most perplexing? Tell us about it in 600 words and we’ll pay you $100 if we publish your case. E-mail Karen Field at: kfield@reedbusiness.com.

The Adventure of the Incredible Sparking Car How could engineers generate a hundred thousand volts with a car’s 12-V system? Find out in the Case of the Incredible Sparking Car on page 22 in this issue.

fiction, there’s nothing I love better than a good mystery. But even Poirot couldn’t hold a candle to the sleuthing abilities of engineers, who are frequently confronted by devilish design challenges and mysterious phenomenon of the most inexplicable sort. To celebrate the most famous investigations into engineering’s most diabolical real-world cases, we’re introducing a new section in this issue called Sherlock Ohms — see page 22. Trust me, these stories are not only extremely entertaining, they may even teach you a thing or two, as many of the tips and tricks of the trade are learned and passed down in just this way. Take the Case of the Shorted Rotor Turns, recounted by design engineer Kunal Ghosh: “Early in my career, I worked for a government organization. I shared my room with a wiring technician, Mr. Singh. He was resourceful and taught me a lot. I did not know the extent of his fame until one day I came to work and found the room full of government officials. They had brought a small rotor from a dc motor that was part of a politically prestigious project. It had a shorted winding they wanted repaired with as little damage as possible. Mr. Singh coolly informed them it would take two weeks to repair. They demanded he do it sooner and left. I was concerned, but the gleam in Mr. Singh’s eye told me he was in command. As usual he was in no hurry. He lit up a cigarette and smoked away in silence. I was growing impatient, but then he told me I was about to see a secret and he preferred I keep it

that way. I agreed. He took out half of a rusty hacksaw blade and a transformer and plugged it into the main ac power. He placed the rotor on the transformer and the blade on the uppermost pole. Nothing happened, so he turned the rotor to the next pole. This went on, pole by pole, until the blade started vibrating violently. He marked the pole with chalk of the shorted winding and verified the health of the remaining windings. After 30 minutes, we had rewired the coil with new wire and the rotor was good as new. I asked Singh how it worked, but he had no technical explanation. It left me to unravel the mystery. An examination revealed that the inverted L-laminations facing each other that made up the top half of the transformer had been cut so that a V-groove was formed. In essence, this alteration allowed part of the magnetic flux to leak from the two faces of the groove. When the windings were placed in the alternating magnetic field, nothing happened to the normal windings. But a shorted winding had an induced alternating current flowing through itself, which in turn created a second local alternating magnetic field just above the shorted coil. This alternating magnetic field caused the steel hacksaw blade to vibrate.” If you have a similar tale, tell us about it and you could get $100 and your Andy Warhol 15 minutes. Contact me at kfield@reedbusiness.com. Karen Field, Editor-in-Chief kfield@reedbusiness.com

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1. Obama Girls Swing with Help from SolidWorks If you’re wondering about what kind of connection could possibly exist between the White House and 3-D CAD software, here’s something to chew on. The much-chronicled play system (or swing set in layman’s terms) that now graces the White House grounds, just a few yards away from the West Wing, was designed and customized using SolidWorks’ MCAD software. http://designnews.hotims.com/23101-516

— Beth Stackpole, CAD/CAM Corner

Standard or Custom Designs for Virtually Any Application — Torque Ratings From 1 oz.in. to 3,000 lb.ft. — Single or Multiple Disc Designs — Power On or Power Off — Cost Effective and Value Engineered

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2. Asian Cars Dominate Ratings ... Again Consumer Reports has published its annual vehicle reliability ratings in its April issue and the results are predictable. Just as they do every year, Asian cars dominate the list of the best. Twenty-nine of the 30 top vehicles stretching from 1999 to 2008 are Asian. Most are Toyotas. North American and European vehicles, meanwhile, dominate the “worst” list. Of the worst 30, 14 are North American and 14 are European. Two are Asian.

Napoleon’s troops literally crumbled to powder after exposure to the frigid cold of a Russian winter. A metastable material, pure tin undergoes a radical structural transformation at temperatures below 0C, essentially decomposing into dust. This transformation, called tin pest, can be avoided by combining tin with other elements like, you know, lead. http://designnews.hotims.com/23101-518

— Karen Field, Made By Monkeys

4. What’s the Deal with Radios and Electronics on Airplanes? I must admit I was somewhat reluctant to address this topic because there has already been a lot written and I fly a lot and I definitely don’t want to offend anyone trying to keep me safe on an airplane. Nonetheless, I was encouraged by one of my co-workers today as we pondered many of life’s mysteries. So for those of you who fly, you know that there are at least a couple of things that are puzzling about electronics usage (or maybe more). http://designnews.hotims.com/23101-519

— Joel Young, The Weird and Wonderful World of Wireless

http://designnews.hotims.com/23101-517

— Charles J. Murray, Electronics News and Comment

3. Did Tin Pest Cause Napoleon’s Wardrobe Failure? With the lingering debate over the reliability of new, lead-free solders dictated by RoHS regulations, the story of Napoleon’s buttons has been making its rounds again in engineering circles. As the story is told to many introductory chemistry class students, the tin buttons on the coats of

5. Concentrate Technology Boosts Part Performance Additives are an area where design engineers could focus a little more time and attention. When added to plastic resins, these chemicals impart a needed property and they also change the mechanical characteristics of the compound. There are also new technologies emerging that can save time and money. http://designnews.hotims.com/23101-520

— Doug Smock, Engineering Materials

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FIVE SOLID SUGGESTIONS

My hat’s off to you sir. Five solid suggestions, “Top 5 Reasons to Stop Whining,” (DN 02.09, http://designnews. hotims.com/23101-521). But I’m surprised at the whining. I guess it’s because it is so easy to do today and there is a venue online for virtually anything. I think your suggestion no. five is perhaps the most important. I was 35 when I got my ME at Florida Tech (UCF), so it was perhaps a bit easier for me. My wife and I became good friends with my advisor and his wife and also got to know another professor quite well through working on the first Mini Baja competition. The personal advice from these two helped immensely in making good decisions through my engineering program. Another thing that helped was becoming close friends with four top grad students. Their immediate knowledge of what I was going through was irreplaceable: getting a sense of each professor and their expectations, quirks, likes, dislikes. We all have these quirks; it can’t hurt for a student to know in advance. I have made it a point to link our aerospace company tightly with Tennessee Tech here in Cookeville and serve on a number of boards. We bring teams of students into our facility for hands-on programs and I even get to teach invention now and then. I haven’t personally seen the complaining you did, but I intend to use your suggestions at those times that I get a chance to speak to student engineers. Rick Larsen Cookeville, TN BOOKS ARE ‘DRY AS DUST’

After last having taken a college-level engineering course about 30 years ago, I decided recently to take a course at UTD. My experience compels me to agree with at least one of the reasons in the “Top 5 Reasons Studying Engineering Sucks” list, regarding the “dry as dust” books. The book from that course, “Digital Signal Processing” by Proakis, is apparently considered a classic and a reference text. It is also one of the most poorly written books I’ve read in many decades. The language hasn’t been updated since what felt like the Middle Ages. It used very stilted, formal language and plodded from one arcane subject to the next without anything to tie the 12

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ideas together or justify how the material would be used in the real world. (It is also FULL of errors, even after six editions)! All that and ONLY $130. I’m also surprised that one of the reasons NOT on the student’s list was “$200K for education and no meaningful engineering jobs when you graduate,” but that’s another topic. Carl Dreher, Ph.D. Focus Research TODAY’S STUDENTS THINK THEY SHOULD LEARN ‘THE GOOD STUFF’

First, I would like to thank you for your editorial in February’s Design News. I don’t think that engineering or technical students are the only ones whining about the contents and relevance of the coursework they are taking. Having a college-age student, I hear similar things from my son’s friends (non-technical majors), as well. Unfortunately, I think this current generation of students thinks they must be entertained and only learn “the good stuff.” They fail to realize that a lot of what they feel is boring useless information is the tools they will need to work on “the good stuff.” I grew up in a family of engineers. My father was an RF engineer, my brother is an analog engineer and I have spent a majority of my career in digital engineering. I understood at an early age what tools were needed to be a successful engineer and, yes, some of it was dry, but absolutely necessary for my success. I think balancing my education with experience (I was an engineer’s assistant in high school and a co-op engineer in college) helped me understand and appreciate even the dryer, less exciting courses within the engineering curriculum. I would encourage any student struggling with the relevance of the coursework to at least do a summer internship and even better take a full fledged co-op engineering position. Rob O’Connor South Iselin, NJ

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line before 1.6 million Americans on the National Mall in January, he was speaking directly to millions of U.S. engineers: “In reaffirming the greatness of our nation, we understand that … the risk-takers, the doers, the makers of things … have carried us up the long road towards prosperity and freedom.” Engineers are the makers of things, and they love the challenge the president poses. Historically, engineers have stepped up. Adversity has fueled innovation. The Great Depression didn’t stop them from innovating. In 1935, DuPont created the first synthetic fiber, nylon, enabling the company to sell 64 million pairs of stockings in the first year. Nylon soon went into parachutes and tents for World War II and is still the second-most prevalent synthetic fiber in the world. A few years earlier, the Galvin brothers, who sold current converters for batteryoperated radios, put a radio in a Studebaker, parked it on a pier in Atlantic City and turned up the volume. Orders flowed in for the first “car radios.” Galvin Manufacturing became Motorola. In 1937, Hormel developed the recipe for canned spiced ham. By 1994 Hormel had sold 1 billion cans of SPAM. Funny food, serious success. The recession of 1969-1970 didn’t stop engineers from innovating, either. That was when engineer Bill Hewlett of HP committed to a far-fetched idea — building a calculating machine that could fit in your pocket. The dot-com bust of 2001 shattered a lot of dreams, but it didn’t stop the creation of JetBlue, or the iPod. Today’s circumstance — call it a recession, depression, disruption or collapse — is no different. Though painful, it will redistribute talent around better ideas and lay the groundwork for a robust recovery.

Those who show courage now will be in the best position to thrive. Colleagues of mine, for example, are working on ideas every bit as audacious as putting ham in a can or 5,000 songs in your pocket. A Burlington, MA company led by Tufts-educated entrepreneur Michael Easton (MicroWind Technologies) is about to test a roof-mounted turbine capable of generating 60 percent of a home’s electricity with a mere 10 mph wind. Engineers in Ontario have designed and built a system that harnesses UV light — not dangerous chemicals — to disinfect as much as 2.2 billion gallons of New York City drinking water every day. Local engineers and doctors (Design that Matters of Cambridge and Center for Integration of Medicine and Innovative Technology of Boston) are developing a sub-$1,000 infant incubator made from car parts. Headlights provide the heat. Every year more than 4 million infants in the developing world die within a month of birth, many of whom could be saved with a warm, clean and easy-torepair environment. Although “innovate or die” is a bombastic way to put it, the concept is true. As always, it’s survival of the fittest. “Economic downturns just speed up the process,” writes investment strategist Andrew Mickey. “It’s accelerated Darwinism.” So, my fellow makers of things, back off your R&D commitment at your peril. Rather, let the urgency of today’s dire economic conditions intensify your innovation efforts. Step to the fore, generate new ideas, support the good ones and execute them. While politicians can inspire, we can get the job done. Jeff Ray is CEO of Concord, MA-based DS SolidWorks Corp., which makes software for engineers.

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Digital Control Systems

mechatronics Electromechanics

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Electronic Systems

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3-D modeling is essential to understanding this branch of mechatronics

he innovation in the products we use everyday has been rapidly accelerated by advances in electronic controls. The actuators, sensors and computer control system cannot be after-thought add-ons. They must be integrated into the system design from the very start. Only through modeling and analyzing can the trade-offs be made between the mechanical and electronic. Simulation and virtual prototypes can also enable more effective collaboration among all engineers. All varieties of motion systems require mechanical dynamic modeling and analysis. The only engineers who really learn dynamics at a university are mechanical/aerospace engineers, and the dynamics they learn is often only two-dimensional. Few students take a second course in dynamics to explore three-dimensional aspects. In dynamics, there is a huge intellectual leap from the two-dimensional to the three-dimensional world. Should every engineer understand three-dimensional dynamics? There are different levels of understanding, so who needs to understand what? To address these questions, I turned to three associates: Jim Ryan, global university program manager for MSC Software which markets Adams, the premier multi-body dynamics simulation software; Professor Shorya Awtar, University of Michigan, Ann Arbor, a mechatronics/machine-design expert; and Professor Phil Voglewede, Marquette University, a kinematics/dynamics expert. Thirty years ago, many complex products and processes were designed around mechanical linkages. As such, tools and techniques were developed to create novel mechanisms to fit virtually any application. Today, however, tools in control system design have opened avenues that would never be conceived 30 years ago, thus enabling the majority of mechanical products to be controlled electronically. The future

A discovery-learning approach to learning 3-D dynamics: Students see the big picture, get curious and motivated, start learning the fundamentals and then apply the fundamentals to the problem at hand. 16

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is in the melding of these disparate fields and the goal is to figure out the optimal mix of the mechanical and electronic. There needs to be a better understanding in all areas. Three-dimensional dynamics problems abound and so it is imperative BY KEVIN CRAIG engineers have access to advanced Kevin C. Craig, Ph.D., courses in dynamics. Computer Robert C. Greenheck simulation tools with three-dimenChair in Engineering sional visualization capability, e.g., Design and Professor of MatLab and LabVIEW, are essential Mechanical Engineering, tools of almost every industry engiCollege of Engineering, neer’s toolbox. Today, engineering Marquette University. students are using these tools as early For more mechatronics as their freshman year. Entry-level news, visit www.mechadynamics courses need to be entronicszone.com. hanced with this capability to make them more effective and be adapted to keep up with the times. A software-based (virtual) approach applicable for both expertdynamicists-in-training (who need in-depth understanding) and for engineers in other disciplines (who need to understand dynamics from an integration point of view), is the Imitate → Assimilate → Innovate approach, shown in the diagram at left. In the imitation phase, the engineer simply performs simulations on pre-built, 3-D, virtual prototypes in order to quickly and painlessly experience dynamics (i.e., how things move). In the assimilation phase, engineers think about the dynamic behavior to more fully understand what causes it and how to control it to obtain desired motion. In the innovation phase, engineers apply what they’ve learned about dynamics in order to virtually design, build, test and iteratively improve their own systems. A balance between fundamental in-depth understanding and multidisciplinary engineering breadth in dynamics is the key to innovation. For More

information

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The World Is Flat — Except in Dynamics!

AERO SP AC

Control Systems

FRESH IDEAS ON INTEGRATING MECHANICAL SYSTEMS, ELECTRONICS, CONTROL SYSTEMS AND SOFTWARE IN DESIGN

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MECHATRONICS IN DESIGN

M E C HAT RO NI CS

Listen to Kevin Craig’s latest webcast delving deeper into the world of dynamics at www.mechatronicszone.com.

S P E C I A L A DV E RT I S I N G S E C T I O N

Design Challenge: Modernize

Equipment for Soldiers By partnering with the right design and manufacturing partner, defense-market engineers can create fresh designs to ease the burden on ground troops hink your job is tough? Try lugging around 80 lbs of gear all day in 100-degree heat while under threat from enemy fire. That’s what our soldiers face in Iraq, and the Defense Department is looking for ways to reduce the sheer weight of equipment that can wear down these troops and hurt their performance. Specifically, the Pentagon has told the EDGE Network, a consortium of leading defense industry

For communications equipment, magnesium injection molding produces parts that are 30% lighter than aluminum, with excellent EMI/ RFI shielding.

suppliers, that it wants to trim 20 lbs of weight from the ground soldier’s equipment ensemble (GSE). Finding that weight reduction will require design breakthroughs in virtually every part of a soldier’s gear: body armor, weaponry, communications equipment and more. With Defense officials calling for equipment that is rugged, yet lighter, more compact and more ergonomic, old approaches to designing and manufacturing combat equipment fall short. It will take fresh thinking to achieve a 25% reduction in GSE weight. A Strategy for Change As design engineers in the defense field take on this tough challenge, one key strategy is becoming clear: Replace conventional materials with new technologies. No matter what the design target — from equipment cases and rifles to goggles and body protection — innovative materials can shed weight, while improving performance in water proofing, impact resistance and durability. By harnessing new manufacturing methods for materials, engineers can make big strides in parts reduction, component miniaturization, and improved ergonomics. Four methods in particular are emerging as standouts —

DoD wants engineers to design a whole range of new equipment with a combined 25% weight savings.

Magnesium Injection Molding (MAG). Magnesium demonstrates excellent performance, especially in communications gear. As durable as aluminum, magnesium offers superior EMI/RFI shielding, even in thin-wall designs. Bottom line: A magnesium housing performs better than one made from aluminum — at a 30% weight savings. MAG combines the best qualities of plastic injection molding with die casting to produce lightweight, high-density, net-shape parts. Components demonstrate excellent properties for stiffness and strength-to-weight. Moreover, you can design MAG parts in a wide array of sizes, ranging in weight from 4 grams to 1800 grams. You can also specify plastic overmolding on magnesium components, as well as special coatings to prevent corrosion. And MAG won’t harm the environment. The material is recyclable, and no ozone-depleting gases are used in molding operations. Metal Injection Molding (MIM). Ideal for manufacturing weapon components and other intricate assemblies, metal injection molding can produce high-volume parts with com-

S P E C I A L A DV E RT I S I N G S E C T I O N

plex geometries, superior strength and excellent surface finish. Using MIM, you can typically produce precisionshaped parts for 50% less than comparable CNC machining or investment casting. Yet finished parts offer the same mechanical properties as those produced by machining. MIM really stands out for parts weighing 30 grams or less. The process can create tiny metal parts with total volume of as little as 0.0001 to 0.003 cubic inches, with tolerances as tight as +/- 0.001 of an inch. Density and mechanical properties are approximately 98% of wrought. Among the many materials choices: stainless steels, titanium, Kovar®, nickel steels, tools steels, tungsten, super alloys, and soft-magnetic alloys. Micro Molding. This manufacturing technique answers the need for miniaturization in soldier equipment, yielding high-precision finished parts as small as a pinhead. Parts measuring just 0.020 inch per side can be molded, and you can specify details such as undercuts, threads, and thin wall sections down to 0.002 inch. Micro molding also yields a larger proportion of finished part to molding runner versus conventional molding, and the investment necessary to produce a part is generally several times lower. In addition, prototype tooling can typically be used in final production. Materials options include: engineering-grade plastics, stainless steel, iron nickel, titanium and ceramics. Multi-Shot Liquid Silicone Rubber Molding ( MS LSR ) . With this innovative process, a designer can get a molded part that combines traditional thermoplastics with liquid silicone rubber. MS LSR is ideal for parts, such as seals, that demand superior biocompatibility, chemical resistance, clarity, and the ability to withstand harsh environments. Among other design advantages, the process can accept a wide range of colorants, while offering temperature resistance up to 410 deg F (210 C). It can also provide bacteria resistance, gas

A trusted partner for Defense designs In Wisconsin-based Phillips Plastics, engineers will find a supplier with broad capabilities in the new technologies required to tackle the DoD’s ambitious weight-reduction goals. As a member of the Edge Network, a consortium of leading-edge defense suppliers, Phillips stays abreast of the new design objectives and performance specs that the military is seeking in next-generation equipment for ground soldiers and other needs. The company also offers extensive production facilities for magnesium injection molding, metal injection molding, micro molding, and multi-shot liquid silicon rubber. In addition, you can harness Phillips’ engineering expertise for design, prototyping, testing, tooling and final manufacturing and assembly. For the special needs of defense designs, Phillips offers secure facilities, class 100,000 clean room production, ITAR registration (International Traffic in Arms Regulation), and ISO 9000:2000

permeability, and excellent light illumination. Plus, you get excellent enduser ergonomics, including parts with a soft feel to the skin. That’s particularly useful for goggles, head phones and ear pieces for communications. Targets of Opportunity With these ground-breaking technologies, opportunities for developing lightweight, high-performance soldier gear are limited only by the designer’s imagination. Among the many immediate applications: mobile battery chargers, compact targeting devices for air support, and joysticks, keyboards and other input devices for communications. The military also wants a long menu of new lightweight devices that soldiers can wear, such as antennas, computers, displays and video receivers. In designing such products, engineers will need to pay more attention than ever to factors such as ergonomics and ease of use. Offering a traditional rectangular metal box with buttons on the top won’t

With the multi-shot liquid silicon rubber process, engineers can design products with a soft-touch feel for ear pieces and other wearable gear. and ISO 13485:2003 quality certification. “The new design mandates for defense require a willingness to look at what can be done with new materials and processes,” says Tom Rothgery, Defense Market director for Phillips. “Engineers should lean on their suppliers to meet that challenge.”

hold much appeal to young soldiers who grew up with clever video game controllers in all sorts of shapes and styles. In short, making the transition from machined or stamped metal parts to new molding technologies requires a paradigm shift in the way engineers design and build military products. That’s why it’s essential to find a supplier who can offer assistance with engineering design, styling and prototyping, with an eye to making the most of such innovative production methods as MAG, MIM, micro molding, and multi-shot LSR. Engineers can download a detailed White Paper on new technologies for improving ground soldier equipment by visiting the Phillips Plastics Web Site: http://designnews.hotims. com/23098-130

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R A Q ’ s

Rarely Asked Questions Strange stories from the call logs of Analog Devices

Keeping Common Modes Common Q.

How come my A/D converter is not able to achieve full scale as the datasheet specifies?

Contributing Writer Rob Reeder is a senior

A. ADC datasheets specify a common-mode voltage requirement for the analog inputs. Not much detailed information is available on this subject, but the proper front-end bias must be maintained in order to achieve rated performance at full scale. ADCs with integrated buffers typically have an internally biased common-mode level of half the supply plus a diode drop (AVDD/2+0.7V). No external circuitry is required to bias this circuit, but it must be maintained to properly use the converter. For un-buffered (e.g., switched-capacitor input) converters, the common-mode bias is typically half the analog supply, or AVDD/2. This can be supplied externally in a variety of ways. Some converters have a dedicated pin that allows the designer to provide bias through a couple of resistors tied to the analog inputs. Alternatively, the designer can connect the internal bias to a transformer’s center tap, or can use a resistor divider off the analog supply (a resistor from each leg of the analog inputs to AVDD and ground). Check the manufacturer’s datasheet or applications support group before using the VREF pin, as many references are not equipped to supply a common-mode bias without an external buffer. If the common-mode bias is not provided or maintained, the converter will have gain and offset errors that contribute to the overall measurement. The converter may “clip” early, or not at all because its full scale cannot be reached. Common-mode bias is especially important when connecting an amplifier in front of the converter, especially if the application calls for dc coupling (required for sampling dc or very

converter applications engineer working in Analog Devices highspeed converter group in Greensboro, NC since 1998. Rob received his MSEE and BSEE from Northern Illinois University in DeKalb, IL in 1998 and 1996

low frequency signals). Check the amplifier’s datasheet specifications to make sure the amplifier can meet the converter’s swing and common-mode supply requirements. Converters have been pushing to smaller geometry processes and therefore lower supplies. With a 1.8-V supply, a 0.9-V common-mode voltage is required by the amplifier. Amplifiers with 3.3-V to 5-V supply voltages may not be able to maintain that low a level, but newer low-voltage amplifiers can. Overlooking a converter’s common-mode input voltage specification can cause havoc in any design. If multiple stages are used, the common-mode levels must be kept the same to prevent the two components from “fighting” each other. One will usually win, producing bogus measurements. For ac-coupled applications, use a coupling capacitor between the two stages to break the common-mode mismatches. This allows the design to optimize the bias of both the amplifier output and the ADC input.

To Learn More About Common Mode Voltages

respectively. In his spare time he enjoys mixing music, art, and playing basketball with his two boys.

Have a question involving a perplexing or unusual analog problem? Submit your question to: raq@reedbusiness.com

For Analog Devices’ Technical Support, Call 800-AnalogD

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FLASH

NEW AND NOTABLE PRODUCT DESIGN

Whether their designs rely on batteries, gasoline or plug-in outlets, engineers are always striving to reduce energy consumption. Specialized power management chips are being fine-tuned, CPUs are running better algorithms and passives are buffering energy to help design engineers do more with less. By Terry Costlow, contributing editor

HAVE LIE DETECTOR, WILL TRAVEL

HELPING THE DISABLED SPEAK Ambient Corp. has designed a compact system that helps people who can’t speak because of neurological disorders, traumatic brain injury, cerebral palsy or other problems. Its Audeo, a wireless sensor worn on the neck, captures the wearer’s neurological activity going from the brain to the vocal cords. This activity is digitized and turned into speech, letting users communicate in person or by phone. A Texas Instruments’ MSP430 microcontroller uses little power and manages overall consumption so the Audeo can last more than eight hours on a single charge. http://designnews.hotims.com/23101-525

Speedy rechargers are helping in the search for truth — honest. Lafayette Instrument Co. has developed the first portable lie detector, employing Bluetooth modules so there’s far less bulk to carry. Wireless data acquisition modules make testing less conspicuous to subjects and keep the weight of five modules under a pound. Those modules can be quickly recharged in case examiners want to test many people. The battery-charging system recharges up to eight Lithium-Ion batteries in just two hours. Microchip’s MCP73863 manages the charging system. http://designnews.hotims.com/23101-526

RACERS BORROW GREEN TECHNIQUES FROM HYBRIDS

Formula One race cars are borrowing a concept used in hybrid vehicles, capturing energy from braking. Magneti Marelli’s Formula One Kinetic Energy Recovery System stores energy created during braking and applies it to provide extra power on demand. Some drivers feel it can improve speed by as much as much as 0.4 sec per lap. Magneti Marelli is using Murata Electronics’ capacitors to store this energy. The EVC series’ ceramic capacitors are small enough to squeeze in anywhere, measuring only 32 x 40 x 3.7 mm — helping reduce weight, which can impact balance and performance depending on the mass distribution inside the car. http://designnews.hotims.com/23101-527

The Adventure of the Incredible Sparking Car

BY ARTHUR SUNDEEN, CONTRIBUTING WRITER Have you applied your deductive reasoning and technical prowess to troubleshoot and solve an engineering mystery that even the fictional Sherlock would find most perplexing? Tell us about it in 600 words and we’ll pay you $100 if we publish your case. E-mail Karen Field at: kfield@reedbusiness.com

Back in the early ‘80s I was an electrical design engineer for an automobile manufacturer. One day the experimental engineering garage called on me to diagnose and remedy a strange, periodic snapping noise that surfaced during the development of a new vehicle. Peering down into the dark, I confirmed that the noise was emanating from a large, arcing spark down low in the engine compartment. The arc was crossing between a small, metal in-line oil filter can and the vehicle’s grounded chassis frame some distance away. The spark was big, fat and loud. It was at least two inches long and occurred about once a second whenever the engine was running. In place of a conventional, vacuum-boosted brake system, this particular vehicle incorporated an experimental hydraulically boosted power brake system. It required an additional hydraulic plumbing from the engine-driven power steering pump to the brake booster system. The plumbing included a fluid filter inserted in-line to the pump’s rubber, high-pressure feed hose. The metal filter housing was suspended by the insulated hose a distance away from the chassis frame. I quickly concluded that a two-inch-long spark equated to at least a couple hundred thousand volts. My first thought was: “How do you get that kind of voltage with a car’s 12V system?” I found it particularly confounding because the vehicle, which used a diesel engine, didn’t even have a high voltage ignition system! I was familiar with generating very high voltages and their principles of operation, having built my own Van de Graaff generator and Tesla coil as a kid. I concluded that, somehow, we had inadvertently produced the “hydraulic” equivalent of a conventional mechanical Van de Graaff generator, which consists of three main parts: an insulated motor-driven electron transport belt, a metal electron collector brush connected to the high voltage metal dome at one end of the belt and a source of electrons applied to the opposite end of the drive belt. In my conceptual “hydraulic” equivalent,

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the moving, non-conducting hydraulic fluid and insulated rubber hoses were the electron transport mechanism. The metal filter can and its internal metal filter element made up the electron collector. The enginedriven hydraulic pump and drive belt were the source of electrons to the fluid. Since the engine-driven pump was of an all-metal construction, and was grounded to the engine and the chassis frame, it was difficult at first to envision how the pump could be a source of electrons. However, I substantiated my suspicion that the pump was the electron source when I attached a grounded test lead to the pump by rubbing it against the pump’s belt-driven pulley and caused the arcing to stop. When the engine was stopped, a conductivity check confirmed that the pulley was grounded in this non-operational state. I then concluded that the pump’s spinning pulley and internal rotor assembly were electrically “floating” inside the grounded pump housing, due to the hydrodynamic action of the bearings and rotor and the insulated seals inside the insulated hydraulic fluid. The actual electron source probably resulted from the triboelectric friction of the rubber drive belt on the pulley. Grounding the filter can housing to the vehicle frame eliminated the arcing symptoms. Upon further reflection, grounding the filter can only provided a good sink for the electrons, and there was still a large circulation of those electrons in the hydraulic fluid. I wonder what, if any, detrimental effects that electron flow would have had on the fluid and the system’s other parts. As I recall, this configuration of power brake booster vehicle never made it into a production vehicle. Arthur Sundeen lives in Michigan, has a BSEE, holds 15 patents and runs his own electrical OEM companies producing aircraft instruments and radio antennas of his own design. You can reach him via our Sherlock Ohms blog comments at http://designnews.hotims.com/23101-528.

Medical device developers and researchers are often the unsung heroes of modern health care. Recently, I had the privilege of speaking to a hundred of them at the Boston-based Medical Development Group, a non-profit industry association. My topic involved leveraging high-brightness LEDs (HBLEDs) in advanced endoscopy applications1, with a particular emphasis on narrow-band imaging (NBI). NBI harnesses two of hemoglobin’s spectral absorption peaks (415 nm and 540 nm, typically) to enhance the contrast of blood vessels which might ordinarily be hidden beneath the superficial layer of the mucosal wall. Because cancers often alter blood vessel structures as they develop, NBI holds promise as an important diagnostic tool in the early detection of cancer and other disorders. But what about the therapeutic applications of light? There is a generally-accepted correlation between regular applications of full-spectrum white light and a reduction of the “winter depression” symptoms of SAD (seasonal affective disorder; possibly due to the relationship between melatonin and the pineal gland). There are also a host of wavelength-specific dermatological and cosmetic LED appliances to treat acne, improve skin conditions, etc. Some recent studies suggest a new, very interesting therapeutic application involving low-level blue lasers. Decreased peripheral blood flow (microcirculation) is associated with many conditions such as diabetes, chronic renal failure, obesity, hypercholesterolemia and advanced age to name a few. In the body, nitric oxide (NO) is one of the most important regulators of microcirculation. Nitric oxide can be bound to hemoglobin as a photosensitive complex known as NO-Hb. One study, reported in the journal Molecular Medicine2, indicated markedly increased perfusion (nutritive blood delivery) when tissue was irradiated with a low-level a 442 nm blue laser. The researchers concluded that the amount of NO released from NO-Hb can be precisely controlled in a local area, and does not interfere with the rest of the circulatory system. Quite remarkable—the implication is accelerated wound healing time. The reason I mentioned these studies is that a new, miniature 450 nm blue laser diode was introduced last month. With a diameter of just 3.8 mm, and a power output of up to 50 mW, perhaps it could have medical applications—such as being integrated into the distal end (the business end) of an endoscope. Imagine the benefit of an instrument which offers both a diagnostic imaging

mode (making blood vessels more visible with 415 nm and 540 nm light) as well as a therapeutic mode to locally enhance the healing of wounds and incisions.

Cary Eskow Figure 1 – The 50 mW blue laser diode in a 3.8 mm package

is director of LightSpeed,

The laser is made by OSRAM, part number PLT4NSB. We have them in stock, but before you call up with a credit card in hand, understand that this is no toy—at 50 mW, it is classified as a Class 3B laser. Class 3B lasers present an eye and skin hazard if viewed directly; this includes specular reflections. It is also not inexpensive like a common 2 mW red laser pointer. In small quantities, initial pricing is over $1,000 each. A simple LM317 regulator configured as a current source and a 9V battery are enough to initially drive the unit.

the solid state lighting and

In applications where you need to convert the beam into a square, rectangle, circle, cross-hair, line or other shape, a simple “engineered surface” diffuser does the job nicely. The blue rectangle appearing on the right in Figure 2 was made by passing a collimated beam through a diffuser made by RPC Photonics. The black box in my hand contains a PLT4NSB, collimating lens and 9V battery.

analog IC and secondary

LED business unit of Avnet Electronics Marketing. An ardent advocate of energy efficient LED-based illumination, he has worked closely with LED manufacturers, advanced optics vendors since his first patent using LEDs was issued two decades ago. LightSpeed works with customers through their national team of illuminationfocused engineers called “Illumineers,” experienced in thermal, drive stage and optics design. Prior to LightSpeed, Cary was Avnet’s

Figure 2 – A narrow beam becomes a more useful rectangle

If you’re considering developing visible HBLED, infrared (IR), IR or blue laser diode systems, let us know how we can help. As always, you can send questions and comments to me at LightSpeed@Avnet.com 1 2

Refer to LM22 at www.em.avnet.com/LightSpeed “Blue laser light... Nitric Oxide from Hemoglobin”, Mittermayr et al, Molecular Medicine 13, Feb 2007

technical director and managed Avnet’s North American FAE team. To submit questions or ideas, e-mail Cary at LightSpeed@Avnet.com

To learn more about designing an LED-based illumination system, go to:

www.em.avnet.com/LightSpeed

T I Pfrom S

TITUS

Unbelievably useful info on data measurement, collection and analysis from the test expert

JON TITUS CONTRIBUTING WRITER

Interpret Acceleration Data Several Ways ACCELEROMETERS LET ENGINEERS MEASURE MOTION

P-P Displacement in Mils

PK Velocity in Inches/Sec

when they test or monitor mechanical equipment or measure the effects of traffic on a bridge or seismic disturbances. These senJon Titus, a former sors have measurement ranges from ±1g for designer and chief a MEMS-based sensor and up to ±10 kg for editor of EDN and a large industrial sensor. The unit g stands for Test & Measurement the free-fall acceleration on Earth; 32.17 ft/ World magazines, sec2 or 9.81 m/sec2. Accelerometers use a varemembers when riety of sensor technologies and can provide “fast” signals operraw, unconditioned outputs or conditioned ated at 10 MHz and outputs in analog or digital form, for example, programs came on 10 millivolts/g or 5 mg/least-significant bit. paper tape. Some sensors’ electronics A will provide rms, peak, peak0.10 Pump Vane to-peak and similar informaPass tion. And they can measure 0.08 Motor 1 x rpm acceleration along one, two 0.06 or three axes. Engineers routinely use 0.04 accelerometers to monitor the operation of large 0.02 rotating equipment such as 0 motors, pumps, rollers and 0 10,000 20,000 30,000 40,000 Frequency in CPM so on. Over time, shafts, B bearings and couplings can 1.0 wear or degrade. These changes cause equipment 0.8 Motor to vibrate more than normal 1 x rpm — often a sign of impend0.6 ing failure. A plot of ac0.4 celeration data versus time Pump Vane will show changes in maPass 0.2 chinery behavior, but a plot 0 of acceleration data in the 0 10,000 20,000 30,000 40,000 frequency domain provides Frequency in CPM more useful information. A Source: Wilcoxon Research fast Fourier transform (FFT) Graph A, top, shows a frequency analydoes the trick and reveals sis of peak velocity in inches/second for a hydraulic pump motor at 1,793 the frequency components rpm, or cycles per minute (CPM). Note in an accelerometer’s signal the high peak due to an 11-vane pump at a given sensor location. impeller. A frequency analysis of peakYou should have a normalto-peak displacement information in operation baseline FFT plot graph B, bottom, shows the motor to use for comparison. causes the most displacement. Keep in mind that acceler26

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ometers have a frequency response, so check manufacturers’ data sheets for a sensor’s useful frequency range. Also, you must use the proper sampling rate for the bandwidth over which you plan to make measurements. Mathematically integrating acceleration over time yields velocity data (v = gt) you can analyze with an FFT, too. But in this type of analysis, some normal vibrations — often called the blade-pass frequency — from fan blades, or from pump impellers or crank shafts, can dominate the frequency spectrum. A six-blade fan spun at 2,400 rpm, for example, has a 240-Hz BPF. Integrating velocity over time yields displacement (d = ½gt2) that you also can subject to an FFT, which produces a frequency versus displacement plot. This type of plot diminishes the displacement at the BPF and emphasizes the greater displacement at the motor’s rotational frequency. Thus the displacement information helps engineers pinpoint characteristics of the motor and other components. Accelerometers can have unusual applications, too. Recently, I read an article about measuring cat-purr frequencies with tiny accelerometers temporarily glued to the skin of several species of cats. Purring occurs at several frequencies between 20 and 200 Hz. I have no clue about who glued the accelerometer on a cheetah. For More

REFERENCES

information

1. “Frequency Analysis in the Industrial Market Using Accelerometer Sensors,” AN3751, Freescale Semiconductor: http://designnews.hotims.com/23101-529 2. “Measuring Displacement Using Accelerometers,” Wilcoxon Research: http://designnews.hotims.com/23101-530 3. “Solving the Cat’s Purr Mystery Using Accelerometers,” Bruel & Kjaer: http://designnews.hotims.com/23101-531

STAKE

Visions for the Engineering Century

They Said What?

New survey reveals Americans’ view of engineering

ere is some happy news. A new national based on old stereotypes and perceptions. survey shows Americans agree with The present reality we must face is that most engineering experts that society’s high- Americans really don’t care about engineering est priorities include making new green energy — they just want us to get the job done and then sources viable, improving urban infrastructure, get back in our cubicles. providing clean water to the world and fightShould we care? Of course. Fewer kids today ing disease. But this same survey also reveals are interested in tackling the universal chalthat nearly half of all Americans think another lenges found in engineering and won’t, so long country has a better shot at delivering on as these perceptions continue to exist them — maybe Japan or China. in our society. Duke University’s Pratt School of As distasteful as it might seem, we Engineering commissioned Hart Remust be willing to use the full power of search Assoc. to measure Americans’ modern media to rebrand the American attitudes toward engineering and the engineer. Quite honestly, it is getting profession’s role in solving the world’s tiresome having to always bring up the toughest problems. You have to be caregood old days, when the challenge of the Geoffrey C. Orsak early space program turned engineerful about imposing your own biases on the results of any questionnaire, but what ing, however briefly, into a heroic profession. It’s jumps out at me from this survey is that people no coincidence we accomplished our greatest don’t know what we do; don’t believe we’re bet- achievements when people cheered for our sucter than we were in the 20th century; and don’t cess. To solve the massive problems the world think engineering is particularly appealing to faces today will require the same kind of national young people as a career. enthusiasm that kept us working round-theIn fact, only 31 percent of adults with some clock four decades ago. college education believe we are more competiFor the sake of our country, and those around tive today than we were in past generations. the globe who depend on our creativity to imOnly 45 percent of prove their lives, we must create a more exciting the college-educated and dynamic culture within engineering to For the sake of our respondents believe reignite national interest in our efforts. The Hart country, and those the U.S. will conreport shows Americans agree on our technoaround the globe tinue to lead the world. logical priorities, they’re just not sure we have who depend on our With no surprise, our the team to get the job done. While we know creativity to improve country’s education better, in this political era, we are going to need their lives, we must system receives most of their support. This challenge is only going to be create a more exciting the blame with 38 per- met by making the effort to share our individual cent of those surveyed stories with friends, neighbors and kids everyand dynamic culture pointing a finger in its where we go. within engineering dismal direction. It is time to stop being shy. Toot your horns to reignite national Even though they engineers ... you invented them after all. interest in our efforts. freely expressed doubt Geoffrey C. Orsak is dean of the Southern Methabout our future, few odist University Lyle School of Engineering. He of the Americans in this survey acknowledged any real familiarity with engineering. Shocked? can be reached at dean@lyle.smu.edu. What people “know” about engineering is sadly

D E S I G N N E W S A P R I L 2 0 0 9 [ w w w. d e s i g n n e w s . c o m ]

INSIDE NEWS

» ELECTRONICS ADI BOOSTS SCANNER PERFORMANCE

TRENDS BREAKTHROUGHS DEVELOPMENTS

ADI’s new current-to-digital converter improves slice counts in CT machines, which could help doctors save lives. Page 36

NEWS

» MATERIALS PARTS BENEFIT FROM CO-MOLDING New ceramic spark plugs are corrosion resistant and cheaper than their metal predecessors. Page 38

» MOTION CONTROL TI ENHANCES MOTOR PERFORMANCE TI’s new family of microcontrollers offers precise control, faster performance and targets real-time control in Motion Control applications. Page 40

» DESIGN TOOLS SPACECLAIM’S FIRST 2009 DEBUT SpaceClaim updates its direct modeling program, with enhanced analysis functions and new model preparation features. Page 42

» MECHATRONICS HARVESTING AN ENERGY PLAN Several companies are researching and developing systems that will allow them to harvest and generate their own energy. Page 44

» SENSORS ON A POWER TRIP The newest sensor from ADI extends the battery life of portable electronics, while using less power. Page 45

Electronic controls, heating and cooling for the Volt’s T-shaped battery pack will be assembled in Michigan. A “stack-and-fold” configuration will enable engineers to pack more energy in the allotted space. V O LT B AT T E R Y

How GM Made the Chevy Volt Battery Decision “Stack-and-fold” shape and better geography were keys By Charles J. Murray, senior technical editor, electronics

General Motors’ highly publicized choice of a manganese spinel chemistry for the Chevy Volt’s lithium-ion battery pack was a carefully calculated move designed to maximize energy, optimize manufacturing and keep the assembly process as close to Detroit as possible, battery experts said recently. The decision, announced by GM CEO Rick Wagoner during a standing-room-only press conference at the 2009 North American International Auto Show, capped off a two-year competition in which the giant automaker auditioned two manufacturing teams for the role of battery supplier for the Chevy Volt. The highly anticipated announcement drew international media attention because the Volt plug-in hybrid is considered to be GM’s biggest project ever and the battery pack is its most critical component. In the announcement, Wagoner said GM will go with a team that includes Korean manufacturer LG Chem and U.S.-based Compact Power Inc., instead of a compet-

After a two-year wait, GM CEO Rick Wagoner recently announced the Chevy Volt will use a lithium-ion battery pack made by LG Chem and Compact Power Inc.

D E S I G N N E W S A P R I L 2 0 0 9 [ w w w. d e s i g n n e w s . c o m ] 3 1

N EWS VOLT B ATTERY, C o n tinued

ing team consisting of A123

Plug-In Hybrid Battery Goals Goals for plug-in hybrid batteries

are more reachable than those Systems and Continental Automotive. The A123 team for pure electric car batteries. employs a nano-phosphateSpecific Energy Cost based lithium-ion battery, 40-Mile Plug-in $293/kW-hr whereas LG Chem’s battery Hybrids 97 W-hr/kg of choice uses a manganese Pure Electric Cars $100/kW-hr spinel chemistry. Plans are for 200 W-hr/kg GM to initially use battery cells from LG Chem’s plant in Korea, then build the entire battery assembly in a GM plant located in southeast Michigan. “We made a balanced decision,” says GM Spokesman Rob Peterson. “Safety was an important part, but ultimately it was no more of a factor than durability, performance, cost and manufacturability.”

Cell Shape Critical

Battery experts say; however, that cell-shape and geography probably had more to do with GM’s decision than any other factor. They suggest LG Chem’s cells, which are flat, are better suited for use in electric vehicles (EVs) than the cylindrical cells proposed by A123 Systems. “If you have cylindrical cells, you can only fill about 75 percent of the volume that’s available to you,” says Elton Cairns, who heads Lawrence Berkeley National Lab.’s Electrochemical Technology Group. “But if you use stacks of flat electrodes, you can fill any space that is parallelepiped-shaped.” As a result, Cairns says, the “stack-and-fold” configuration of the LG Chem cells probably appealed more to GM engineers, who are trying to maximize the amount of energy per unit volume they can draw from the lithium-ion battery pack. LG Chem’s “stack-and-fold” battery configuration could also simplify the Volt’s manufacturing process. “Stack-and-fold is easier for a large electrode manufacturer,” says Mohamed Alamgir, director of research for Compact Power Inc., which will initially integrate and assemble the battery pack for the Volt prototypes. “Winding them around a mandrel would be no trivial task.” Moreover, GM executives may have been swayed by the geography of their battery decision. Today, plans are for the cells to be manufactured by LG Chem in Korea, then sent to Michigan, where Compact Power Inc. will work with GM on integrating electronic controls, heating, cooling and cabling into the battery pack. Ultimately, GM has said it plans to take over the assembly process once its own plant is up and running. “We’ll start preparing the factory in early 2009 and we will start loading the (manufacturing) equipment into the factory at mid-year of 2009,” says Peterson of GM. Battery experts believe GM ultimately wanted to take over the assembly process and possibly even move cell manufacturing to Michigan, as well. “It’s one thing to buy headlamps from someone,” says Donald Sadoway, the John F. Elliott professor of materials’ chemistry at MIT. “But the battery is an integral part of the power train, so it makes sense for GM to buy the cells from a

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N EWS VOLT B ATTERY, C o n tinued

reputable source and then over time, by joint venture or perhaps with its own new technology, build a plant where it can manufacture the battery under its own supervision.” The plan is consistent with GM’s well-known propensity for building a high fraction of its own vehicles, rather than farming out significant parts to vendors. Some say GM executives also preferred the prospect of initially having its cells manufactured in Korea, as opposed to China, where A123 planned to initially build its batteries. “Make no mistake about it,” says an automotive engineer who asked not to be named. “If you or I had to decide between batteries made in Korea or batteries made in China, I’d choose Korea 100 out of 100 times.” Goals within Reach

Questions about testing still remain, however. No matter which vendor provided the battery, GM would still have been in the position of having to test it on an accelerated schedule, largely because the Volt’s rollout is planned for 2010. Engineers at GM have said they would have preferred to test the batteries over a 10-year period, but given the high customer demand for the vehicle today, their development schedule wouldn’t allow it. For automakers — including GM, Ford, Chrysler and others planning to use lithium-ion batteries — the question is whether such accelerated testing will provide the information they need. “People try to take the results of accelerated testing and extrapolate them to a much longer lifetime under normal use,” Cairns says. “But unless the failure mechanisms are the same in both kinds of testing, you don’t really know how to extrapolate those results to real-world time. That’s the big pitfall. You can’t afford not to do stress testing. But on the other hand, it’s not very clear how you should interpret the results.” Battery experts say; however, the goals for the Volt battery pack are far more realistic than those GM faced in the EV1 project. Back then, battery makers were targeting specific energies of more than 200 W-hr/kg and costs of $100/kW-hr. But plug-in hybrids like the Volt, augmented by an internal combustion engine and generator, are now shooting for 97 W-hr/kg and $293/kW-hr, according to figures from the U.S. Advanced Battery Consortium. Experts say the needed specific energies are available today and the costs, although not there yet, are coming down. “Even with the very best of today’s batFor More tery technology, you information cannot have a reasonGM’s Chevy Volt: ably designed (pure) http://designnews.hotims.com/23101-532 electric car that will Compact Power Inc.: go 300 miles between http://designnews.hotims.com/23101-533 charges,” Cairns says. A123 Systems: “But once you put an http://designnews.hotims.com/23101-534 internal combustion Continental Automotive: engine on board, the http://designnews.hotims.com/23101-535 goals are within reach.” Read more about the Chevy Volt: http://designnews.hotims.com/23101-536

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A new data acquisition chip may lay the groundwork for faster, higher-quality computed tomography (CT) scanners. Analog Devicesâ&#x20AC;&#x2122; new ADAS1128 current-to-digital converter could serve as a key element in the drive to boost the number of slice ADIâ&#x20AC;&#x2122;s tiny ADAS1128 chips pack 128 data counts in CT scanacquisition channels, which translates to ners, which in turn higher slice counts for CT scanners. could help physicians more easily diagnose machines, one could image maladies ranging from cancer the heart in a single shot,â&#x20AC;? to cardiovascular disease to Pavlik says. â&#x20AC;&#x153;And in addition orthopedic injuries. The new to doing that, you could do converters would accomplish animated views of the heart that by enabling scanner manuas itâ&#x20AC;&#x2122;s beating.â&#x20AC;? facturers to incorporate more The current-to-digital conof the detectors that are responverters, which convert light sible for the slice counts. photons to digital signals, could â&#x20AC;&#x153;The trend is toward higher also help to make CT scanners and higher slice counts,â&#x20AC;? says faster and more affordable. The Scott Pavlik, strategic marketdevices can reportedly boost ing manager for imaging paspeed from 6 kilosamples per tient monitoring at ADI. â&#x20AC;&#x153;The second (kSPS) to 20 kSPS and reason is that if you have more reduce system electronics by slices, you have more area to 50 percent compared to older capture the image.â&#x20AC;? designs, ADI says. ADIâ&#x20AC;&#x2122;s converters help acâ&#x20AC;&#x153;It all translates to faster scan complish that by integrating times,â&#x20AC;? Pavlik says. â&#x20AC;&#x153;It will allow a 24-bit analog-to-digital hospitals to diagnose patients converter with 128 data acmore quickly in an emerquisition channels â&#x20AC;&#x201D; about gency room or to increase the four times as many as the throughput of patients through norm for such devices. That a given machine.â&#x20AC;? allows scanner manufacturers to pack more detectors into a ELECTRONICS For More smaller area, which is signifiinformation cant because such machines Analog Devicesâ&#x20AC;&#x2122; ADAS1128: typically use about 1,000 http://designnews.hotims. detectors per slice. As such, com/23101-538 Learn about data converters state-of-the-art, 320-slicethat cut time to market: count machines use approxihttp://designnews.hotims. mately 320,000 detectors. com/23101-539 â&#x20AC;&#x153;In these high-slice-count

» MATERIALS

Co-Molded Ceramics, Metals Boost Part Properties New spark plugs are cheaper, more corrosion resistant

By Doug Smock, contributing editor, materials and fastening Two-component plastic injection molding is a well-developed process to produce parts that combine properties of two different polymers, such as a hard core from polypropylene and a soft cover from thermoplastic elastomer. Now researchers in Germany are trying to achieve the same effect with ceramic matched to metal or one type of ceramic married to another ceramic via the powder injection molding process. “If we want to combine metals with ceramics or different ceramics with one another, we need to find materials that will shrink to the same extent at the same temperatures,” says Dr. Reinhard Lenk, a project manager at the Fraunhofer Institute for Ceramic Technologies and Systems in Dresden, Germany. Shrinkage rates are even more important in powder injection molding than in plastic molding because

powder components also go through a sintering process to remove plastic binders. Materials’ engineers simulated shrinkage behavior of a wide variety of materials before identifying candidate feedstocks with necessary mechanical properties. In a specific project sponsored by the European Union called CarCIM, engineers produced prototype diesel spark plugs from two different ceramics. The new plugs are described as more durable, more corrosion resistant and cheaper than traditional metal igniter plugs. The two ceramic materials provide, respectively, insulation and electrical conduction. The conductive material is molded, inserted into another tool and over-molded with the insulating composition. Dr. Tassilo Moritz, who heads the CarCIM project, says the insert process is faster and cheaper than traditional assem-

Source: Fraunhofer

Black and white zirconia feedstock is combined in a molded process that offers engineers new design combinations.

bly methods such as soldering. The co-molded part is then sintered using kinetic models, says Moritz. The critical interface between the two materials has been studied and verified with optical and electron microscopy. Other testing methods have also been used to improve process parameters. Particle size distribution of the powder is a critical factor, according to the Fraunhofer investigators. For More

MATERIALS

information

Fraunhofer-Gesellschaft: http://designnews.hotims.com/23101-540 Read more about the co-molding process: http://designnews.hotims.com/23101-541

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» MOTION CONTROL

Real-Time Controller Boosts Motor Performance Better math performance, PWM modules make performance faster, more precise

By Charles J. Murray, senior technical editor, electronics Texas Instruments (TI) has rolled out a family of floating point controllers aimed at boosting real-time performance of high-end industrial motors in motion control applications. Known as Delfino C2834x, the new family of 32-bit microcontrollers is said to offer more precise control of motor torque and acceleration because it employs a 300-MHz core, 32-bit floating point unit and up to 516 KB on-chip random access memory (RAM). “In servo drives, customers are looking to improve efficiency and they want to get better control over multiple motors,” says Keith Ogboenyiya, microcontroller manager for advanced embedded controllers at TI. “With this, they can do it with a single controller.” TI engineers say their new devices could help with real-time control applications for two reasons — math performance and interrupt latency. They claim the new de-

vices can do a 32-bit multiply/accumulate in a single cycle, which could be beneficial in executing control algorithms packed with math calculations. They also say the C2834x incorporates special hardware that enables the controllers to quickly handle multiple interrupts, which is critical to enabling them to work without getting bogged down. The addition of 65-picosecond (ps) highresolution pulsewidth modulation (PWM) modules could also boost precision in motion control applications, the company says. “Having 65 picoseconds of resolution means that you’ve got that much more granularity to turn on and off your PWM,” Ogboenyiya says. “In many applications, such as motor control, it gives you more resolution, which directly affects motor performance, torque and acceleration.” TI is targeting the new microcontrollers at families of motors because it says the

TI’s Delfino C2834x can enhance performance, torque and acceleration in servos, permanent magnet and brushless dc motors.

new CPUs are code-compatible with previous devices. That, in turn, could allow motor makers to incorporate a single code base across a family of motors and drives. As a result, TI engineers foresee the basic technology being applied to permanent magnet and brushless dc motors, as well as servo drives. “Having a system that is scalable from the high end to the low end is a plus because it saves on R&D dollars and software resources,” Ogboenyiya says. For More

MOTION

CONTROL

information

Texas Instruments’ Delfino C2834x: http://designnews.hotims.com/23101-542 Read about smart motor control technology: http://designnews.hotims.com/23101-543

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» DESIGN TOOLS

SpaceClaim Updates Direct Modeler in First 2009 Release Updated tool includes new model preparation, enhanced analysis features

By Beth Stackpole, contributing editor, design tools Continuing the industry momentum behind direct modeling, SpaceClaim rolled out the fourth release of its 3-D design tool offering, including new model preparation and enhanced analysis functions, along with enhancements for dealing with multi-CAD models. SpaceClaim, a direct modeling program released in April 2007, reopened an on-going debate in the CAD industry over the merits of parametric or history-based CAD tools and direct modelers. In the year or so since the SpaceClaim debut, there has been a flurry of announcements and activity in the direct modeling space. Among them are Siemens PLM Software’s Synchronous Technology, found in its NX and Solid Edge 3-D MCAD tools, PTC’s acquisition of CoCreate and, most recently, Autodesk’s preview of its Inventor Fusion technology.

According to proponents, direct modeling capabilities provide greater flexibility, a shorter learning curve and more “design freedom” than traditional history-based CAD tools, thereby serving to open up the market to non-CAD jockeys. “We see direct modeling as the vehicle to break the glass ceiling of one million seats sold of solid modeling tools and get an order of magnitude of new growth in the market,” says Blake Courter, SpaceClaim’s co-founder. SpaceClaim is hoping the features of its first new 2009 release will help propel such growth. SpaceClaim Engineer, the flagship tool, has new model preparation tools to detect and repair problems with imported designs and simplify models prior to analysis, according to Courter. The software also offers increased surfacing power for highly stylized designs and features new

Engineers of different disciplines can balance trade-offs in SpaceClaim to create a new product concept in the context of CAD data from existing designs.

analysis tools for industrial design visualization and manufacturing validation. Pricing for SpaceClaim Engineer starts at $1,995 a seat. For More

DESIGN

TOOLS

information

SpaceClaim: http://designnews.hotims.com/23101-544 Siemens’ Synchronous Technology: http://designnews.hotims.com/23101-545 Autodesk’s Inventor Fusion: http://designnews.hotims.com/23101-546 Hybrid modeling approaches take shape: http://designnews.hotims.com/23101-547 Watch a webcast on the direct modeling versus history-based CAD debate: http://designnews.hotims.com/23101-548

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» MECHATRONICS

New Generation MEMS Promise Energy Efficiency Twenty-one companies are tackling devices that create their own energy

By Howard Baldwin, contributing editor applications in a variety of areas that require Research and development into microelecsmall sensors and accelerometers, according tromechanical systems (MEMS) that harvest to a new report from Yole Development. LP-046-C outlines.ai 9:48:21 AM and generate their own energy will3/4/2008 have Energy harvesting has the most viabil-

The EnOcean PTM 200 wireless switch works without a battery. It generates its own energy when its clip is pushed within a range of 300m.

ity, says Yole Analyst Laurent Robin, in conjunction with other technologies, such as wireless sensor networks. “In that situation, you need wireless technology that consumes little power. You can do it with RFID, Zigbee or Bluetooth,” he says. The MEMS can serve a variety of industries, Robin says, noting they are already available in building and home automation, in military and aerospace and will soon appear in the automotive field. He cites the example of the PTM 200 wireless switch from EnOcean, a spin-off company of Siemens, which could be set up as any kind of switch, including use with lights. “When the user pushes the clip, it generates energy that sends a signal to a receiver to put the light on,” he says. “You save money by not having to wire another switch and you have the flexibility to put it anywhere.” In military and aerospace applications, vibrations can be harvested to power a sensor running what’s known as a health and usage monitoring system (HUMS) for either helicopters or fixed-wing aircraft. These systems, made by companies such as RSL Electronics, can be programmed with accelerometers to measure the state of components or sensors to gauge temperature. For More

M E C HAT RO NI CS

information

Yole Development: http://designnews.hotims.com/23101-549 EnOcean: http://designnews.hotims.com/23101-550 RSL Electronics: http://designnews.hotims.com/23101-551 For more mechatronics’ news, visit www.mechatronicszone.com.

Power Management

» SENSORS

Sensor Adds Functions While Minimizing Power

3 Axis Sensor

By Randy Frank, contributing editor Consumers seem to want more and more from cell phones and other portable devices. Unfortunately, more functions usually translate into lower battery life, even if the cell phone is not used for calls. With its ADXL345 digital accelerometer, Analog Devices has taken steps to minimize the impact of adding an accelerometer to battery-powered products and actually reduced system power consumption. A triaxial accelerometer provides motion sensing for converting human movement and gestures to a range of interactive system functions for users. Popular features include pedometer functions for health-conscious consumers, landscape-to-portrait and horizon-orientation photo features for phones and digital cameras, and the integration of wrist movement, shaking, rolling and other actions into the interactive gaming experience for mobile entertainment devices. Accelerometers also provide shock protection for hard disk drives. To provide these functions and extend battery life, the ADXL345 three-axis accelerometer boasts the lowest power consumption in its class with an 80 percent power savings compared to competing three-axis inertial sensors. Consuming as little as 25 µA in the active mode is important, but is only a part of the power management aspect. The real power savings is at the system level. To get a current reduction in milliamps instead of just fewer microamps, ADXL345 circuitry contains a FIFO (first-in/first-out) memory block. Storing readings in the accelerometer reduces the microprocessor’s operation in its active state providing a power consumption reduction in the milliamp range. SENSORS

information

ADI’s ADXL345 digital accelerometer: http://designnews.hotims.com/23101-552 Visit Design News’ sensors microsite at www.designingwithsensors.com.

Sense Electronics

A/D Converter

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To provide a significant system level power reduction and longer battery life, ADI’s ADXL345 accelerometer has an integrated power management block.

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TREND WATCH//MATERIALS

CERAMICS New Grades Target Tough Applications Ultra-high-purity alumina is aimed at extreme-duty semiconductor markets BY DOUG SMOCK, CONTRIBUTING EDITOR, MATERIALS AND FASTENING

Design engineers can expect increasing opportunities to use ceramics for demanding applications as new high-performance grades emerge and high-level players develop processing capabilities. CoorsTek Inc. opened a specialty materials’ center in Golden, CO that focuses on developing next-generation ceramic materials for applications in high-technology markets including semiconductor, electronics, laser, advanced armor, medical and several others. New processing, manufacturing, finishing and materials’ analysis equipment were added to enable ultra-high material purities, increased material characterization detail, faster material development cycles and expanded advanced processing capabilities. “Our ultra-pure ceramic materials capability will support nearly all of our industries — especially the stringent demands of the semiconductor manufacturing market as they move beyond 45 nanometer devices,” says Frank Anderson, director of technology for CoorsTek.

ROTATING RUNNER FIGHTS ABRASION

The Ceradyne Stack Bearing is a hydrodynamic pad-type bearing that uses a rotating runner. The wear surfaces use an advanced grade of silicon carbide that is 50 percent tougher than other grades of silicon carbide. Ceradyne says the hardness of the material prevents abrasive failure in highly demanding applications such as oil and gas drilling where rolling element bearings are often used. “The abrasives simply polish the SiC surfaces,” says Russ C. Ide, new products manager at Ceradyne and an inventor of the system. “The significant technological improvement lies in the patented spring mounting component that allows each pad to develop an optimum fluid wedge, equally load each pad in a bearing and then equalize the loading among a stack of bearings and runners.” http://designnews.hotims.com/23101-554

4 6 D E S I G N N E W S A P R I L 2 0 0 9 [ w w w. d e s i g n n e w s . c o m ]

HIGH-PURITY ALUMINA OFFERS ETCH RESISTANCE CoorsTek developed an ultra-high-purity ceramic material designed specifically for extreme-duty semiconductor applications. In addition to very high purity, PlasmaPure-UC alumina offers high etch resistance in corrosive chemistries, very low sodium content and an extremely low dielectric loss tangent of <0.00002. The fine-grained material also possesses four times better corrosion resistance and six times lower sodium content than competitive alumina materials. “Outstanding material property data and very positive customer trials have proven the material quite effective at extending component life and greatly reducing contamination,” says Mark Petty, executive vice president of CoorsTek Inc. http://designnews.hotims.com/23101-553

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ZTA-FB 99.8% Pure For demanding applications where the strength Alumina Toughened of alumina is insufficient. Available in white and with Zirconia black, maximum temperature of use is 400C. TZP-A Zirconia

For parts with excellent surface quality requirements and reproduction of fine details. Delivers good wear resistance and high strength in such applications as biomedical, micro-engineering and fiber optics. Maximum temperature of use is 400C. Source: Phillips Plastics

MOLDING CREATES COMPLEX DESIGNS Strong potential for ceramic components is attracting new suppliers, such as Phillips Plastics of Prescott, WI, which is applying precision moldmaking and processing capabilities to ceramic injection molding. The combination of ceramics with the injection molding process provides several benefits to design engineers, including production of small, highly complex geometries not possible with other ceramic forming processes, high strength, superior corrosion resistance, excellent surface finish and consolidation of multiple components into a single design. http://designnews.hotims.com/23101-555

MOTOR CONTROL ICS

TREND WATCH//MOTION CONTROL

Maximizing Power

New designs optimize thermal properties, input voltage, output current, size and cost

SINGLE-CHIP

INTERLEAVED PFC CONTROLLERS

BY AL PRESHER, CONTRIBUTING EDITOR

Texas Instruments’ UCC28070 and UCC28060 controllers provide an interleaved power factor correction (PFC) control circuit for multi-kilowatt communications, server and industrial systems. The two-phase, average current-mode 28070 controller allows designers to simplify their power design, increase system reliability and achieve a greater than 0.9 power factor rating, which also improves energy efficiency. Key features include interleaved average current mode PWM control and an advanced current synthesizer for superior efficiency, accurate current sensing and high power factor. The 28070 also provides highly linear multiplier output with internal voltage feed-forward correction for near unity power factor, programmable switching frequencies (30 to 300 kHz), selectable frequency dithering for reduced EMI and phase management for high-efficiency, light-load operation. http://designnews.hotims.com/23101-556

Optimizing the use of input voltage and maximizing output current are key benchmarks for power management devices designed for motor control applications. Managing thermal properties is vital, along with adding value to the design by adding built-in features and functionality. With product trends moving toward more miniaturized designs, especially for handheld and battery-powered devices, the focus is on form factor and cost. “The real driving force for our new 3908 part, beyond the normal specifications of the output current and input voltage, is the package size,” says Tim Rowan, strategic marketing manager for Allegro MicroSystems Inc. By specifically targeting an application for cell phone lens’ covers, a new eight-pin DFN package that is only 2 x 2 mm is able to replace a package that was twice the size.

NEW LOW-VOLTAGE, BI-DIRECTIONAL DC MOTOR DRIVER

Allegro MicroSystems Inc. has introduced a new low-voltage bidirectional dc motor driver with a typical input voltage range of 3.0 to 5.5V and output currents up to 500 mA. The unique full-bridge output incorporates source side linear operation to allow a constant voltage supply across the motor coil. This regulated output minimizes motor voltage change due to I*Rds (on) variation and battery voltage tolerance. Allegro’s new motor driver is targeted at the portable and instrumentation markets. Two logic inputs are provided to control the motor direction of rotation, brake and standby (< 500 nA supply current) modes and to allow optional PWM of the sink drivers. Internal protection circuitry includes thermal shut down, under voltage lockout and crossover (shoot through) protection. http://designnews.hotims.com/23101-557

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THREE PHASE FIELD EFFECT TRANSISTOR PRE-DRIVER The 33937 is a field effect transistor (FET) pre-driver from Freescale Semiconductor designed for three-phase motor control and similar applications. The integrated circuit (IC) uses SMARTMOS™ technology, and contains three high side FET pre-drivers and three low side FET pre-drivers. Three external bootstrap capacitors provide gate charge to the high side FETs. The IC interfaces to a MCU via six direct input control signals, an SPI port for device set up and asynchronous reset, enable and interrupt signals. Both 5.0 and 3.0V logic level inputs are accepted and 5.0V logic level outputs are provided. The 33937 is fully specified from 8.0 to 40V, covering 12 and 24V automotive systems, and offers an extended operating range from 6.0 to 58V. http://designnews.hotims.com/23101-558

FLUID POWER/POWER TRANSMISSION

SPACE-SAVING BY AL PRESHER, CONTRIBUTING EDITOR

DIVERTER Rodless cylinder provides compact, integrated solution for conveyor systems

Stroke is contained within anufacturing and packaging facilithe length of the actuator ties move and sort tons of bulk on conveyors, but the sorters, diverters and pull-offs that route products must be as trim as possible to make the most of valuable floor space. Engineers at Hytrol Conveyor Co. needed a more effective, space-saving solution when designing a diverter for an overhead pull-off system that would divert 150-lb boxes to a different conveyor line. Tolomatic’s BC2 “Our conveyors are used to move products down the rodless pneumatic cylinder offers equal line, divert them to the next station in the manufacturing piston areas in both process or, if a product is defective, divert them to a reject Adaptive mounting system directions, eliminatline,” says Jackie Smith, an application engineer at Hyreduces assembly time ing load variations, trol. “When we needed to design a diverter that was more while also saving Cushions protect load on installation costs. compact and could be simply integrated into our systems, and actuator from damage we decided to employ a different type of actuator.” Source: Tolomatic The traditional actuator used to operate diverters on ing wear and load deflection compared to rod-style cylinders. a conveyor system is a pneumatic rod cylinder. Normally, a As a result, bending moments are better controlled, resulting rod cylinder with up to a 48-inch stroke would be mounted in longer wear without seal or bearing stress. off to the side, perpendicular to the conveyor, and operate a Hytrol initially looked at other types of actuators, but liked the paddle that pushed a product off the conveyor or diverted it to size and performance of the rodless actuator and found it easy to a different line. However, these rod-style diverters consumed mount within its pull-off design. Rodless cylinders offer equal a lot of space because the cylinder extended about 48 inches piston areas in both directions, eliminating load variations. Plus, beyond the width of the conveyor. the load and piston have a floating connection, resulting in less When floor space is at a premium, Hytrol now offers a friction and longer seal life. framed overhead diverter design that uses a Tolomatic BC2 “In Hytrol’s overhead diverter design, the actuator has to rodless pneumatic actuator. The BC2 actuator’s length is the move a large triangular paddle that pushes boxes weighing same as the conveyor’s width, and the carriage moves entirely up to 150 pounds,” says Holloway. “This can create very within the length of the actuator. high bending moments on the actuator’s carriage and guide “The BC2 actuator is a space saver,” says Guy Holloway, bearings. The BC2’s carriage has a very robust bearing system president of Fraleigh Co., the local distributor that helped design the application. “The length of the rodless actuator is with higher side-load capacity. When designing for very high bending moments, sometimes we specify dual carriages on the the same as the width of Hytrol’s conveyor, making it much simpler to work it into new or retrofitted diverter stations. It actuators to distribute the forces.” can be mounted over or under the conveyor.” FLUID POWER/POWER TRANSMISSION For More A rodless band cylinder actuator contains its stroke within information the length of the cylinder itself. For example, a 2-inch bore Tolomatic’s BC2 rodless pneumatic actuator: rodless band cylinder, with a 48-inch stroke, can provide 43 http://designnews.hotims.com/23101-598 percent space savings compared to an equivalently sized rod For more fluid power/power transmission news, visit cylinder. A rodless actuator also guides and supports the load http://designnews.hotims.com/23101-599. throughout the entire stroke length, so there is minimal bear[ w w w. d es ig n n e ws.c o m]

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FLUID POWER/POWER TRANSMISSION

Closed Loop HYDRAULICS

High-speed die-casting press uses PID algorithm for fast positioning BY AL PRESHER, CONTRIBUTING EDITOR

digital inputs. Using a FPGA, the signals for encoding posiosition and pressure control of a hydraulic cylinder tions were handled directly from the sensors. “We didn’t need is a common application, but precise control of an intermediate processing or amplification device, and we these systems has traditionally presented significant achieved an evident reduction of noise and a correspondent challenges because of the high speeds and pressures. increase in processing speed,” he says. When machine builder Euro Electronics designed a A key to the system is the cylinder movement precisely followclosed-loop hydraulic cylinder control system for a die-casting press machine that included press moves anywhere from 0 to 10 ing the position, speed and acceleration profiles determined by the supervisory software. In a process cycle faster than 1 msec, msec, they knew it would require a high-speed control system. “In our application, the cylinder moves over a softwarethe valve position is measured, the speed is calculated, both are defined trajectory with specific velocity and acceleration compared to the set point and the movement is corrected using a profiles that must guarantee accuracy and repeatability up to PID algorithm. To keep the hydraulic circuit balanced, pressure a maximum speed of 10 msec,” says Paolo Catterina, an envalues in the front and back of the cylinder are simultaneously gineer for Euro Electronics. “For reliable control of cylinder controlled in order to avoid instantaneous peaks. The ability to effectively close the loop over the hydraulic braking and acceleration, the closing of the loop must perservo valve is possible only if the proform at 1 kHz processing rates.” To meet the challenge, Euro Eleccessing cycle time is absolutely detertronics developed a system using the ministic and the hydraulic circuit is LabVIEW FPGA module and Comresponding quickly, precisely and repactRIO hardware from National petitively. In this case, the hydraulic Instruments. Using the integrated servo valve was controlled through FPGA on the controller, the company an analog output signal. developed a system capable of lowPrecise tuning of the PID algorithm level customization using commerwas achieved through calculations cially available tools. They also impleusing a linearization “table” of the remented a highly optimized encoder sponse values for the valve, which has interface in the FPGA to measure the Euro Electronics went from prototyping to unique nonlinear characteristics. Uscylinder position while programming final setup of the machine in three weeks. ing this PID gain scheduling method, the system entirely in LabVIEW. Euro Electronics obtained very acEssentially, the system controls the cylinder position to curate responses both at low velocities (from 0.05 to 0.30 msec track the velocity and acceleration trajectory values the opera- during the start movement of the cylinder) and at high velocitor enters. The operator can control the cylinder movement ties (the real maximum speed reached is 7.5 msec). through a PID algorithm using pressure sensor feedback that Using feed-forward and smoothing techniques on the comis on the order of a few milliseconds. mand signal, they calibrated the PID algorithm so that in rapCatterina says the first thing to consider when choosing an id commutation points movement instability was eliminated. acquisition system is the quality of sensors required for presFLUID POWER/POWER TRANSMISSION For More sure measurement and position. In this application, they utiinformation lized linear magnetic stripe sensors for position measurement because the signal processing interface for the sensor signals National Instruments’ LabVIEW: http://designnews.hotims.com/23101-600 must be fast and rugged. For more fluid power/power transmission news, visit He says they were able to fully implement the encoder funchttp://designnews.hotims.com/23101-599. tion for cylinder position control using just two high-speed

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FLUID POWER/POWER TRANSMISSION

Stabilizing Controls BY AL PRESHER, CONTRIBUTING EDITOR

System uses combination of servo and hydraulic motors to position camera mast

tion to the mast under strong wind conhe design solution for a porditions where unequal forces resulted in table, battery-powered giant excessive torque demand as the control mast and camera for aerial system tried to correct the error. coverage of sporting events reThe solution was to use the controlquired more than the average amount of ingeler in position control mode with the nuity and a mix of servo and hydraulic motors effective length of each guy rope preinterfaced to a single motion controller. cisely maintained relative to the height Building a camera mast that extends as of the mast as it travels up or down. high as a 12-story building with the dyThe wind force on each side of the namic stability to support a full-sized 50-kg mast may vary, but a combination of camera at speeds of 2m per second in high tensioned guy ropes, with exactly the winds is a challenge. But the design requiresame length, maintains optimal mast ments also included stowing and operating stiffness without adding deflection. the mast from a single-axle trailer and selfTo meet the requirements for contained operation from batteries. self-powering the trailer and battery Trio Motion Technology’s MC206X mooperation, all components needed tion controller provides position and stato be as energy efficient as possible. bility control for a 30-m camera mast that Hydraulic motors fitted to each wheel provides sweeping high-angle aerial shots are independently controlled to drive for film and TV. The Vortex Aerial Mount and maneuver its 3,400-kg payload. Camera System was developed by camera- Stabilizing the camera on the long mast is achieved by independently tensioning Four outriggers used to level the trailer man Matthew Gladstone of Cammotion and tight synchronization of the Kevlar are also hydraulically powered. The and automation specialist Machinery Con- guy ropes, the main mast winch and camera position. hydraulic power packs include variable trol Systems (MCS). speed drives for the pumps. The most impressive part of the Vortex “The decision to use battery power is the design of the mast itself and the mohad a major influence on the design and choice of compotion control system that smoothly positions the mast nents of the electrical and control system,” says Tim Oxtoby, and provides the high stabil- managing director of MCS, who designed the control system. He says they used a mix of variable speed and servo moity control required during tors and a 220V, three-phase supply to maintain the power filming. Stabilization conrequired. Controlling the hydraulics from the same source trol is accomplished using allowed them to effectively manage the entire system in a four Kevlar guy ropes fixed seamless way. at the top of the mast and Since the hydraulics and servo motors are not used at the controlled from servomosame time, switching the control to each system saves costs by tor driven geared winches using just one MC206X with an optional daughter board for bolted to outriggers on the five axes of servo control. trailer. The guy ropes are independently tensioned in FLUID POWER/POWER TRANSMISSION For More tight synchronization with information each other, the main mast Trio Motion Technology’s MC206X: winch and camera position. http://designnews.hotims.com/23101-602 MCS initially tried The camera mast uses lightweight Cammotion’s Vortex Aerial Mount Camera System: carbon fiber to maximize its stifftorque control on each guy http://designnews.hotims.com/23101-603 ness-to-weight ratio and linear rope but that resulted in For more fluid power/power transmission news, visit bearings to minimize deflection. adding unwanted deflechttp://designnews.hotims.com/23101-599.

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FLUID POWER/POWER TRANSMISSION

Harnessing

Wind Power

BY AL PRESHER, CONTRIBUTING EDITOR

Power transmission plays critical role in the efficiency and reliability of wind turbines

apturing the power of the wind is pushing industry to develop power transmission technology that can deal with highly dynamic conditions harnessing wind power creates. Efficiency of the turbines is critical because it plays a key role in energy generation, but reliability and effective maintenance are also essential for success. “Wind energy is exciting technology that can be cost-competitive, but the challenge is improving the reliability of the wind turbines,” says Douglas Lucas, manager of application engineering, wind energy at The Timken Co. “The dynamics of the wind, deflections in the turbine system and inertias in the drive train components all cause dynamic complexities in the gearbox specifically and the whole drive train system in general.” Bearings in industrial applications are typically designed to last from 20 to 30 years. But the variability of wind, the flexibility of the towers The loads imposed on wind turbine and torque spikes that systems are very dynamic, includoccur from all of those ing the movement of the tower, variations can result in constantly shifting winds and everimpact loading in the changing position of the blades. turbine. The impact loadings, along with the variable torque throughout the entire drive train from the gear box to the generator, can cause significant power transmission challenges. Lucas says these challenges are providing the focus for research and development efforts. The National Renewable Energy Lab. has a project looking at the system dynamics of wind turbines and gearboxes. There is also a focus on condition monitoring and understanding how these systems are operating dynamically. Power transmission components for wind applications are being designed and calculated to achieve a 20- to 30-year life. But based on his experience in the industry, Lucas says the tur[ w w w. d es ig n n e ws.c o m]

Integrated Flexpin bearing technology from Timken allows gears to deflect without misalignment, improving system reliability in wind turbine applications.

bines and gearboxes are not achieving that level of reliability. “In other applications for a power generation piece of equipment, we can get units to last 20 to 40 years but that’s a gearbox that is being mounted on a solid pad, seeing constant speed and predictable load conditions. The unit is inspected and proper maintenance is performed on a regular basis,” Lucas says. “There is no variable loading. Add in the dynamic movements of the tower, which can be moving back-and-forth several meters, and the fact that the wind is never constant and is always changing. Plus the position of the blades is also changing, so the loading throughout the entire system is very dynamic.” Bad weather creates an additional set of problems. The industry does consider the extreme load events and calculations to analyze power transmission components from the standpoint of both normal operating and extreme loads. But there are factors which may not be able to be accounted for. In response to these engineering challenges, Timken and other power transmission suppliers are optimizing their fundamental technologies and offering specific products aimed at increasing the efficiency and reliability of the power train for

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ADVERTORIAL

CONSIDER OPERATOR SAFETY WHEN DESIGNING HYDRAULIC SYSTEMS FOR FAILURE PREVENTION Hydraulic assembly failures may be caused by excessive pressure surges, flexing, kinking, crushing, exceeding the minimum-bend radius of the hose or reaching the end of the useful life of the assembly. To avoid hose failures, Gates recommends design engineers: 1. Select a hose that has a working pressure rating that is equal to or higher than the maximum pressure (including surges) of the application. 2. Consider a spiral wire-reinforced hose rather than a braid-reinforced hose if the application has a heavy-duty cycle or frequent pressure surges that approach the maximum working pressure of the assembly. 3. Reroute hoses to eliminate excessive flexing. 4. Make sure hose bends are not tighter than the minimum published bend radius for the hose. Use bent tube couplings, adapters or bend restrictors to relieve stresses on the hose. For hydraulic hoses containing fluid with a pressure of more than 5MPa (50 bar) and/or having a temperature over 122°F (50°C), and which are located within a three-foot line-ofsight of the operator, Gates recommends an extra safeguard – a double-layered protective sleeve. Gates LifeGuard™ sleeve has an inside layer that elongates to absorb the energy of a burst or pinhole leak. The outer layer restrains the fluid and redirects it safely to the clamped ends.

Both nylon layers of the LifeGuard sleeve provide containment of 6,000-psi bursts and 3,000-psi pinhole leaks at 212°F, thus protecting operators, equipment and the environment from the hazards of catastrophic hydraulic hose failure. Visit www.gates.com/lifeguard-dn

FLUID POWER/POWER TRANSMISSION

an adequate supply of fresh grease is dewind power applications. livered to the bearings at all times. A key goal is friction management. “Part of our product focus is on use Designs and bearing configurations that of cleaner steels,” says Lucas. “We try are more optimal can increase the effito keep the size and number of incluciency of the turbines and gearboxes by sions down to a low value to increase reducing the amount of friction in the the life of the product. When a bearing bearings, and heat generation that afstarts to get damaged, subsurface rolling fects the overall cost per kilowatt hour. contact fatigue can be a problem. With One solution is low torque or fuel-effewer inclusions in the steel, there is less ficient bearings where the geometry of chance for rolling the raceways and contact fatigue surface finishes to occur and for are optimized to the stress profile reduce the rolling underneath the friction. In other raceway to create industrial market high maximum segments, this shear stress. If approach reduces you can minimize bearing power those stress conconsumption, centrations under the result of the the surface, you amount of friction can improve the between the comreliability.” ponents, by more The company’s than 30 percent DuraSpexx™ and has helped fuel efficiency up bearings are to 2 percent. manufactured Planet Pac from Timken enables designConcentrausing highly ers to use thicker gear sections in smaller diameter gears. This creates more radial tion on a group refined steel, space for larger diameter rolling elements of fundamental providing twice that add to bearing capacity. technical issues is the fatigue life of also important to normal bearings improving system performance. Key and making it easier for wind turbine technical breakthroughs include work design engineers to improve the power on engineered surfaces where coatdensity of their projects. ings and finishes can enhance bearing Promoting power-dense designs is fatigue life, corrosion resistance, speed important for these applications. Power capabilities and friction reduction. density is achieved by using smaller Another area is debris solutions. bearings and or putting more power Bearing raceways are frequently reinto the same volume of steel. In some quired to operate in lubricants that are wind power gearboxes, some of the bearcontaminated with large-particle debris ing components have been integrated emitted by gears and other sources. into the gear or shafts to reduce weight These large particles dent bearing raceand system inertia which can be affected ways and typically reduce the fatigue by some of the system dynamics. life of standard bearings. Specialized One example of advanced gear drive bearings help withstand these effects to technology developed for wind applicamaintain gear box reliability. tions is Timken’s Flex Drive System with Lubrication options and condition Integrated Flexpin Bearing Technology, monitoring systems are also important, which uses an integrated flexible bearespecially for effective system mainteing in the planetary portion of the drive nance. Single-point lubricators can help train to allow the bearing and planet reduce service intervals and ensure that gear to deflect into the system while still

FLUID POWER/POWER TRANSMISSION

maintaining accurate and reliable gear tooth contact. “This is an innovative design that can be used to optimize and reduce the size of the gearbox,” Lucas says. “If the customer wants to put additional power into that same gearbox, Flex Drive System can be added to allow more power regardless of the deflections in the rest of the system.” A final critical issue for these systems is maintenance. Wind turbines are often quite inaccessible for maintenance purposes because they are located on mountains, in deserts or on the coastlines of the North Sea. Condition monitoring systems help monitor performance, and predictive maintenance increases performance and reliability of the drive train systems. But generally the goal is to achieve a one-year maintenance cycle on the turbines, so timing of maintenance is typically longer than the six month maintenance schedule for turbines mounted on land. Until the economic changes at the end of 2008, Timken’s Lucas says he expected the wind energy market to grow at an exponential rate. But now the wind energy market is expected to grow at a slower rate, even though funding from the stimulus plan should have a positive effect. One concern is the connection of wind turbines to the

mainland grid system. Typically where there is good wind, there aren’t many people living there and so industry is dependent on the grid to transport power. Particularly in North America, grid efficiency is absolutely one of the key issues for industry to meet the goals for renewable and wind energy. “We are pleased that governments in our growth areas, such as Europe, Asia and North America, understand this and intend to take aggressive actions to address the issue,” says Hans Landin, director of the front end unit for wind energy at Timken. “We are very optimistic for continued growth in China, where they understand this issue and are making infrastructure investments to facilitate expansion of wind turbines and wind energy.” For More

FLUID POWER/POWER TRANSMISSION

information

The Timken Co.: http://designnews.hotims.com/23101-606 The National Renewable Energy Lab.: http://designnews.hotims.com/23101-607 For more fluid power/power transmission news, visit http://designnews.hotims.com/23101-599.

® PENINSULAR C Y L I N D E R C O.

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COVER STORY

The Dawn of

NANO-ENERGY Irregular mechanical motions could be converted to usable energy

STORY_CHARLES J. MURRAY, SENIOR TECHNICAL EDITOR, ELECTRONICS

ot long ago, it would have been unthinkable: Creating usable electrical energy through the movement of a hamster, vibration of vocal chords, tapping of fingers or flapping of flags in a breeze. We’re talking about tiny energy sources here. Not the spinning of the hamster’s wheel, but the movement of the hamster itself, the motion of its legs, the bending and twisting of its tiny torso. And finger tapping? Not a hard thump, but a gentle rapping of a pinky finger against a hard surface. That’s all it takes to produce energy. Moreover, in the world of unlikely energy sources, these examples are not isolated. There are floor tiles at Purdue University that create electricity when someone walks over them. There’s an automo-

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tive shock absorber at MIT that harnesses energy from bumps in the road. Hearing this, any self-respecting engineer might ask, “Sure, but how much energy? And what could you possibly use it for?” Therein lies the key question. Improbable as it may seem; however, engineers say this new breed of energy sources may produce enough electrical current to help run low-power applications, such as PDAs and embedded microcontrollers. The aforementioned tap of the finger on a PDA’s display might bend a piezoelectric element just enough to yield a trickle of current, thus recharging a battery. A temperature gradient between the human body and ambient air might help charge an implanted Georgia Tech’s Zhong Lin pacemaker. Or a thermometer. Or a blood Wang has crepressure monitor. ated “charge “We’ve had a lot of people call us and pumps” that use say, ‘I’ve got this energy source …,’” says a piezoelectric Kevin Parmenter, an applications’ engieffect to create neer for Freescale Semiconductor’s Analog small amounts and Mixed Signal Power Div. “They say, of ac current in ‘It’s cool, but it only puts out so much response to mevoltage and I need to know what I can do chanical stress. with half a volt.’” Augmenting Battery Power

Turns out there are things they can do with half a volt. At Georgia Institute of Technology, one researcher demonstrated his idea with the hamsters, not because he believes rodents will supplant coal-burning generators, but because he wants to show even the most miniscule of mechanical motions can produce electrical current. What’s more, he’s proving that by using enough tiny generators (nanogenerators, he calls them), engineers might eliminate the need for batteries in some low-power applications. Zhong Lin Wang, a Regent’s professor at the school, says a sheet containing tens of thousands of the nanogenerators could fit beneath a Blackberry’s touch screen, enabling the handheld device to draw power from the finger-tapper. The sheets could also be used to power sensors that measure blood sugar levels or to augment batteries in implantable medical devices, such as defibrillators. “The whole reason we did this is that batteries run out of power,” Wang says. “If you have a small generator, you can integrate it together with the battery and then you don’t need to replace the battery as often.” Indeed, Wang says he believes some applications could be run exclusively by his nanogenerators, although it could take thousands or even millions of the nano-devices to run a small

electronic product, such as a cell phone. To be sure, Wang’s nanogenerators are tiny. Configured as extremely small wires, they’re made from zinc oxide and measure between 100 and 800 nanometers (nm) in diameter, and 100 to 500 microns (µm) in length. Put another way, their diameter is about ¹/50 of a human hair; length is about 10 hair-widths. Moreover, the amount of electrical current they produce is equally miniscule. When Wang and associates at Georgia Tech recently fitted a hamster with a four-nanogenerator jacket, it generated 0.5 nanoamps (nA) of current. The nanogenerators accomplish that through a piezoelectric effect — a well-known phenomenon in which a material creates a small amount of current in response to mechanical stress. Wang’s nanogenerators are different from other piezoelectric devices; however, in their ability to draw current from virtually any mechanical motion. “Most piezo materials use a resonant frequency to generate current,” Wang says. “Ours is much smaller and we don’t need a resonant frequency.” Indeed, Wang’s piezo material can produce electrical current at frequencies ranging from a few hertz to hundreds of kilohertz. That’s a major departure from conventional piezoelectric elements, which are cantilevered like diving boards and require a strong mechanical deflection and an ensuing resonant frequency in order to create electricity. To produce more power, Wang’s research team can make the nanogenerators in sheets. They encapsulate the single zincoxide wires in a flexible polymer substrate. Wires are anchored at the ends with an electrical contact and a Schottky Barrier to control current flow. A “sheet” with about 10,000 nanogenerators measures about 4 cm long, he says. Wang says the ability to draw current from virtually any mechanical frequency makes it possible for the technology to serve in a variety of medical applications. Defense experts are also looking at it as a way to power tiny gas sensors for soldiers. “All we need is mechanical bending — back and forth — any

By putting a jacket with four nanogenerators on a hamster, researchers created about 0.5 nA of current. D E S I G N N E W S A P R I L 2 0 0 9 [ w w w. d e s i g n n e w s . c o m ] 5 1

COVER STORY

The zinc oxide wires serve as “nanogenerators,” producing less than a nanoamp of current when they are stretched or bent. Unlike conventional piezoelectrics, the nanogenerators don’t need to reach a resonant frequency in order to produce electrical energy.

kind of mechanical disturbance,” he says. “It’s a key difference and it truly expands the range of applications for this technology.” Ready for Prime Time?

These days, energy harvesting research seems as if it’s everywhere. At Purdue University, a group of undergraduate students recently created a tile floor that produces electricity when people walk across it. As part of their senior capstone design project, the students built a small floor of 10 x 10-inch tiles, laid four piezoelectric elements (Thunder actuators from Face International Corp.) beneath each tile, bolted the floor to the substructure and placed springs stop the bolts to enable the floor to flex. The result: When a force is applied, the springs compress and the piezo elements activate, producing electricity. The students suggest the technology’s use in airports and train stations where, in some cases, hundreds of thousands of travelers per day would cross the floors. “There’s a lot of energy that’s being burned by people walking in malls and airports,” says Eckhard Groll, a professor of mechanical engineering at Purdue and the academic advisor for the electric floor project. Still, Groll says the floor technology isn’t ready for prime time yet. Putting piezo elements in every tile is not cost-effective, he says. Even if manufacturing costs drop as production volume rises, the tiles can’t come close to the cost of carpeting or linoleum. And that, he says, will be the determining factor for many energy-scavenging technologies. “It becomes a question of how much does a floor like this cost and how much electricity will it actually produce? At current electricity prices, you might not get a payback for a long time,” Groll says. “But as electricity becomes more expensive and manufacturing prices come down, it might look different in ten years.” For such systems to eventually succeed, one other hurdle 52

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must also be crossed. Most “nano-energy” technologies operate from a few millivolts (mV) to about 800 mV, which isn’t enough for many embedded applications. To deal with the problems, electronics’ manufacturers have started marketing converters designed to boost the scavenged voltage to a more usable level. Freescale Semiconductor, for example, has developed an ultra-low-voltage dc-to-dc converter aimed at applications involving solar cells and other energy-harvesting systems. The unit enables operation at levels as low as 0.25V. That’s significant because most ICs cannot start up at levels less than the typical turn-on voltage of a transistor, which is approximately 0.7V. “Our converter takes that low voltage and boosts it to about 5V, regulated,” says Parmenter of Freescale. “That way, you can do things with the energy you harness.” New Uses for Low Power

Moreover, the range of possibilities is growing. Potential applications include garage door openers, electronic sensor systems for soldiers and cell phones. “In cell phones, the RF amplifier generates heat,” Parmenter says. “What if you could put a little heat sink on there? One side gets hot, the other gets cold and you use the waste heat to charge the batteries.” Parmenter says Freescale has received dozens of requests for technical assistance in enabling such systems. “We’ve had discussions with people who make portable applications of all kinds, including defense and homeland security,” he says. “We’ve talked with people who make survival radios for the military. People want to get rid of their batteries — or least charge them less often.” Some companies have even talked about using human body heat as a source. One manufacturer is said to be designing bandages with built-in thermometers. Another has reportedly tried to use human temperature gradients to power battlefield computers. “A few months ago, I would have said no one can use such low power,” Parmenter says. “But now, you can do something with it.” For More

information

Freescale Semiconductor: http://designnews.hotims.com/23101-559 Georgia Institute of Technology: http://designnews.hotims.com/23101-560 Face International Corp.’s Thunder Actuators: http://designnews.hotims.com/23101-561 Video of how the movements of a hamster can be converted into electricity: http://designnews.hotims.com/23101-562 Video of the technology charging a lithium-ion battery from a solar cell: http://designnews.hotims.com/23101-563 Video of how a human muscle stretch can generate electricity: http://designnews.hotims.com/23101-564

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NITROGEN FOAM Giant plastics event will showcase the latest in plastics technologies to improve the environment

Microcellular foam can cut part weight. Engineers can see the MuCell process actually making parts at the Engel Booth at NPE 2009.

Source: Engel

his year’s National Plastics Exposition in Chicago (June 22-26) will T be a great place to scout new green materials technologies. Look for the latest engineering ideas ranging from bioplastics to new materials and processes that reduce component weight. One promising idea for design engineers is microcellular foam, which will be demonstrated at the Engel booth (24000) in McCormick Place South. Controlled use of supercritical gases, such as nitrogen, during injection molding, produces a 10 percent or more reduction in part weight and significant energy savings. And because cycle times are reduced, presses are 20 to 33 percent more productive. The technology, originally developed at MIT, is targeted at precision and engineered plastic components with maximum wall thicknesses of less than 3 mm. Key quality parameters, such as flatness and warpage, are also improved because pack and hold phases in the injection cycle are eliminated.

Engineers at Southco, a major fastening technology company, are among the super users of the MuCell foam process. “We typically seek to achieve a 5 percent weight reduction, but our customers aren’t overly concerned with that,” says Southco’s Principle Engineer Glenn Anderson. “They’re primarily after improved quality. We do experience cycletime savings to some degree based on the part being produced, but that’s more of a side benefit at this point in time.” Anderson says Southco has achieved as much as a 40 percent reduction in part weight. Southco also achieved improved torque strength and better dimensional control on a glass-filled nylon pushto-close part, in addition to improved manufacturing efficiency. Warping and sink marks caused by thick cross sections were eliminated with the MuCell process. Anderson says another major benefit is aesthetics. Boosts Auto Business

Southco leveraged the technology im-

provements to win business in the automotive industry. “I’m always looking for a competitive edge for potential programs,” says Bill Sokurenko, business development manager at Southco. “The automotive industry is high on innovation, but they’re also very conservative. MuCell helped us win business on large automotive programs because of the benefits we gained.” Southco has made more than 6 million parts a year for automotive customers with the MuCell process. “We’re still looking at highly engineered, functional touch points in vehicles that are A-surface components (where MuCell could be applied) whether they’re on the instrument panel or in and around the general cockpit area,” says Sokurenko. The big new push for the microcellular foam will be in large-part automotive applications. At the NPE, Engel will be showing parts made on a 1,000-ton press using the “core-back” process, in which the back of the mold is partially extracted

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GREEN TECHNOLOGY

of parts made with the MuCell process ey can I save. after an initial using the new screw.” With engimold filling. The Ticona produces LFRT grades neered fastenfoam continues through use of pultrusion technology ers, we need to expand, creatthat fully impregnates the long fibers to make sure ing a multilayer to deliver optimal reinforcement to the we have the structure. plastic matrix. Unlike conventional design marMazda anSource: Southco nounced the core- Good aesthetics are one of the benefits of micro- gins where we short-fiber-reinforced materials, the longer fibers present in molded parts need them so back process re- cellular foam, as seen with these glove box latch mechanically interact with each other that we don’t duced component handles surrounding a housing. to form an internal glass fiber “skeleton” have any isweight up to 30 that limits anisotropic shrinkage and percent and will be used on parts for 2011 sues downstream. Each tool brought its greatly reduces warpage. model year cars. Initial target applications own characteristics in terms of how you would mold solid or in MuCell.” for the process include instrument panel “To succeed with core-back, you retainers and door panel liners. Bioplastics Surge need precision machine technology,” “When you combine core-back and Among other green highlights at the adds Engel’s Braig. Position and clamp the MuCell process, you can essentially National Plastics Exposition will be new force need to be precisely controlled. saturate the polymer with super critiplastics made from renewable resources. More than 300 machines globally are Some of the key players include: cal fluid or gas in its supercritical state, now making parts with the MuCell prowhile keeping the mold closed under DuPont (West Hall, booth number cess. Other commercial parts include pressure,” says David Bernstein, presi113011) is expected to exhibit its latest electrical components, electronics, dent of Trexel, which was granted an plastics made from agriculturally sourced business equipment and printer compo- polylactic acid. Sorona EP, Hytrel RS exclusive license to market the MuCell process. The mold can then be precisely nents, as well as packaging containers. and Zytel RS include renewably sourced The process is totally different from opened to get maximum expansion. biobased ingredients and can deliver gas-assist injection molding, in which “You get a much thicker part, but one additional benefits, such as improved gas goes into a mold cavity following that is much less dense, in fact as much stain resistance, appearance and better as 75 percent less dense,” says Bernstein. resin injection and is used to push the durability when compared to their petromelt stream to the cavity wall. In the The bubbles in the outer layer are leum-based counterparts. For example, microscopic to ensure necessary strength MuCell process, supercritical fluid is Sorona EP polymers contain between 20 injected in the barrel and is part of the and rigidity, while the size of the bubbles and 37 percent renewably sourced matein the core layer can be adjusted to reduce melt stream. rial (by weight) derived The MuCell process its density as desired. Because the core from corn. Initial works without chemical back process controls the foam’s strucgrades with 15 and 30 blowing agents, hydroture, it can be used to enhance the heat percent glass-reinforcecarbon-based physical insulation and acoustic characteristics ment were made availblowing agents, nucleof plastic parts, according to Mazda. able last year for develSource: Southco Steve Braig, president of Engel’s North ating agents or reactive Latches perform better with micro- opment programs. components. As a American operations, says the process Metabolix (West cellular foam because of reduced warpage. result, the Trexel prois suited for any flat parts. “Design enHall, booth number cess can handle a wider gineers can now re-think the mechanics 119020) will show range of melt indexes than conventional on some existing applications in plastic products made from its Mirel polymers, foaming processes. because dramatic weight reductions are which are harvested from vats of geIn one of the newer developments, realistic,” Braig says. Trials are conducted netically modified microbes that feed MuCell can now be applied to long-fiat Engel’s factory in York, PA, one of two on glucose from plants, such as corn. remaining factories in the U.S. that make ber-reinforced thermoplastics (LFRT) Metabolix and Archer Daniels Midland from Ticona. injection molding machines. Co. are commercializing Mirel through “Virtually warp-free, lightweight Implementation of the MuCell proa joint venture called Telles. parts molded of Celstran LFRT are now cess is not easy. “A person implementFor More a viable option for OEM designers and ing the MuCell technology really has a information injection molders developing large parts steep learning curve to understand how National Plastics Exposition: and structural profiles,” says Steven Basto make the process work and how to http://designnews.hotims.com/23101-565 setti, marketing manager for Ticona. ensure reliable output,” says Southco’s Southco: “The Ticona team, working in conjuncGlenn Anderson. “Also, if you’re makhttp://designnews.hotims.com/23101-566 tion with Trexel, developed extensive ing a plastic bucket, for example, you Read more about Dow Chemical’s plans to may not really care that much about the data for the Celstran LFRT grades using build a polyethylene plant in Brazil at mechanical properties. You’re interested polypropylene and nylon 6 and that will http://designnews.hotims.com/23101-567. in how does it look and how much mon- help customers predict the performance 56

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BEST OF THE ENGINEERING MARKETPLACE 59 63 64 65 66

E l e c t ro n i c s Fluid Power H a rd w a re / S o f t w a re Materials/Fastening M o t i o n C o n t ro l

Compiled by Elizabeth M. Taurasi and Sasha Brown-Worsham

ELECTRONICS

TNEWPORT’S ORIEL® SOL3A™ CLASS AAA SOLAR SIMULATORS For testing, measurement of solar cells Oriel® Sol3A™ large-area, constant wave (CW) sources use an xenon lamp and feature a proprietary filter to meet Class A performance parameters — spectral match, non-uniformity of irradiance and temporal instability of irradiance — without compromising 1 sun output power. Each version is certified to IEC 60904-9 2007 edition, JIS C 8912 and ASTM E 927-05 standards. Offered in 2 x 2, 4 x 4, 6 x 6 and 8 x 8 inch sizes, simulators suit testing and measurement of solar cells. Newport Corp. http://designnews.hotims.com/23101-570

SOMEGADYNE’S STRAIN GAGES Line includes linear, shear, double shear, full bridge, linear diaphragm styles Omegadyne’s transducer quality strain gages can be used in almost any type of application and are available in linear, shear, double shear, full bridge and linear diaphragm styles, in both constantan or karma versions. The gages typically come in packages of 25, 50 or 100 and custom gages can also be designed within two weeks or less. Omegadyne Inc. http://designnews.hotims.com/23101-568

KAVLICO PRESSURE SENSORS Designed to address the needs of the refrigeration market Kavlico has a full line of pressure Kavlico sensors (P158, P528, P4000, PT250/PT251, P250/P251, P250R/P251R) specifically designed to address the needs of the refrigeration market. Whether the application calls for measuring chiller pressure, supermarket refrigeration, refrigerant suction and discharge, or hydronic system pressure and steam recovery, Kavlico sensors have been designed to perform. Kavlico http://designnews.hotims.com/23101-569

-PHJD Siemens provides a clear advantage in performance. Logic control is expected of an automation controller. However, when performance is critical to the success of your application, SIMATIC S7 Controllers deliver:

• Built-in Diagnostics • Scalability TPOSITRONIC’S PCIC3W3 COMPACT POWER CONNECTOR Suitable for use in high working voltage applications The PCIC3W3 variant is suitable for use in applications with working voltage requirements of up to 2,000V rms. Three size 16 power contacts, spaced at 7.33 mm, are rated at 32A each continuous per UL1977. Contact resistance is 0.0007Ω. The connector is available with a jackscrew locking system. Positronic Global Connector Solutions http://designnews.hotims.com/23101-571

• Speed • Flexibility

Compare your controller to SIMATIC S7 Controllers. www.sea.siemens.com/S7logic

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TMICROPOWER DIRECT’S A500RHI SERIES OF CONVERTERS

ELECTRONICS, Continued

SSCHURTER’S SERIES 6135, 6136 POWER-ENTRY MODULES

High isolation, 5W single- and dual-output dc/dc converters Targeting board-level power applications, the A500RHI family of 5W single- and dual-output dc/dc converters from MicroPower Direct includes features such as an I/O isolation of 5,600V dc, an operating efficiency to 80 percent and a leakage current of 2 µA max. Twelve models operate from wide 2:1 inputs of 9 to 18, 18 to 36 and 36 to 75V dc, providing outputs of 5, 12, ±12 or ±15V dc. All models are approved to UL 1950 (IEC 60950) safety standards and include continuous short circuit protection, overload protection and an input under voltage shutdown. Each model is specified for operation over the wide operating temperature range of -40C to +55C ambient with no derating or heat sinking required MicroPower Direct LLC http://designnews.hotims.com/23101-574

For applications with high inrush currents, high transient loads The Series 6135 and 6136 power-entry modules from Schurter Inc. are a combination of appliance inlet and circuit breaker that provide an alternative to fused power-entry modules. Both modules are especially suited for applications with high inrush currents and high transient loads. The ability to manually reset the circuit prevents the expense and inconvenience of fuse replacement.

4BGFUZ Siemens is the safe and responsible choice. Accommodating both standard automation and safety, SIMATIC S7 Controllers eliminate the need for two controllers, saving significant cost while reducing complexity. S7 Controllers provide:

• Certified Compliance

Schurter Inc. http://designnews.hotims.com/23101-572

• Easy Integration • Common Platform PROTEK’S MODEL 667C

SKEYSTONE’S QUICK-FIT PCB TERMINALS Tin-nickel plated, available in single tab configurations Keystone’s .110-, .187-, .205- and .250inch Quick-Fit terminals (2,79; 4,75; 5,20 and 6,35 mm) with rivet-type mounting bases are manufactured from tin-plated brass and have 0.109- through 0.135-inch mounting holes (2,76 to 3,43 mm). They are available in single tab configurations. Keystone Electronics Corp. http://designnews.hotims.com/23101-573

• No Extra Engineering

Features 2-inch jaw opening Offering true, reactive and apparent power measurements, three-phase, digital power Clamp Meter measures threephase, three-wire, three-phase, four-wire, and single-phase circuits to 600V at 1,000A. Its 10,000 count, four-digit dual LCD shows selected power measurement and stores up to 28 of them in memory. Featuring a 2-inch jaw opening, the device can measure volts, amps, kilowatts, VA, VARs, KWh, power factor and frequency. The unit includes RS232 interface and tool box carrying case. Protek Test and Measurement http://designnews.hotims.com/23101-575

Compare your controller to SIMATIC S7 Controllers. www.sea.siemens.com/S7safety

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ASHCROFT® INC.’S PRESSURE TRANSDUCERS

FLUID POWER

For harsh media Ashcroft®’s pressure transducer products are used in applications ranging from high-volume OEM to general sensing and heavy industrial. A full line of high-quality Ashcroft® pressure transducers, manufactured by Dresser Instruments, meet the most demanding applications. Ashcroft® Inc. http://designnews.hotims.com/23101-578

TCLARK SOLUTION’S ULTRASONIC FLOW TRANSMITTERS

SRED VALVE’S NEW SERIES DX SLURRY KNIFE GATE VALVE Keeps gate path, seat area clear Able to handle heavy slurry applications, the Series DX slurry knife gate valve provides drop tight shutoff in both directions. When the valve opens, reinforced elastomer sleeves seal against each other and provide full port opening to minimize turbulence. Seats isolate and protect all metal parts of the valve from coming in contact with the process. The valve is designed to discharge a small amount of slurry during strokes, keeping the gate path and seat area clear of entrapped particulates. Red Valve Co. Inc. http://designnews.hotims.com/23101-576

Ideal for green technology applications Featuring brass construction, CSLFB Ultrasonic Flow Transmitters offer full-scale flow ranges from 15-400 gpm in ¾-3 inch pipe, with accuracy of ±0.75 percent. Devices are based on mixed signal ASIC, which combines timing, control and transducer drive circuitry. Units measure flow rates of acoustically conductive liquids, including most clean liquids and many liquids with entrained solids. Output is unaffected by changes in fluid temperature, density and viscosity. Clark Solutions http://designnews.hotims.com/23101-579

.PUJPO Siemens is the right choice to keep your operation moving forward. The reality of machine control is that both motion control and automation must work in tandem. SIMATIC S7 Controllers approach automation and motion as a single control task, providing:

• Libraries • Wizards • Flexibility • Simplicity SOMEGA’S FSW-420/30 SERIES OF THERMAL FLOW SWITCHES

BESWICK ENGINEERING’S NEW MINIATURE BALL VALVES Offer compact size, lightweight, non-restricted flow The Beswick sub-miniature ball valve is offered in two standard configurations. If you require an on/off valve, the MBV1010-303 is the answer. If your application requires the selection of one of two possible flow paths, the MBVT-1010-303 should be specified. Beswick Engineering Co. Inc. http://designnews.hotims.com/23101-577

No moving parts, easy to install The FSW-420/30 series of thermal flow switches has no moving parts and monitors relative flow rate for applications where the actual flow rate is not important. This CE-compliant product features automatic scaling and set-point with pushbutton re-scaling. Perfect for industries involving flow and temperature control or alarm and applications involving automation and process cooling. OMEGA ENGINEERING Inc. http://designnews.hotims.com/23101-580

Compare your controller to SIMATIC S7 Controllers. www.sea.siemens.com/S7motion

H A R D WA R E / S O F T WA R E

TOTHER WORLD COMPUTING’S VOYAGER PRODUCT LINE Hard Drive Docking Bundles, Firewire 800/400 compatible OWC’s Voyager product line includes a docking mechanism that allows users to insert any standard 2.5- or 3.5-inch SATA I/II hard drive with up to 2.0TB capacity and then connect to a Mac or PC via a quad-interface options, including FireWire 800, FireWire 400, USB 2.0 or eSATA.

SAVX’S COMPONENT MODELING, SIMULATION SOFTWARE Allows designers to view all basic characteristics AVX Corp.’s new component modeling and simulation software, the Designated AVX Component Simulator, enables designers to view all basic characteristics and parameters for Accu-P, Accu-L, Thin Film Low Pass Filters, Couplers, 3dB Splitters, Hi-CV SMT, LICC, LGA and IDC products. The simulation software features multiple parameter graphing options including Smith Charts, S-parameter, ESR, impedance, current, inductance and capacitance values. AVX Corp. http://designnews.hotims.com/23101-581

Other World Computing http://designnews.hotims.com/23101-582

SPENTEK’S MODEL 7153 DIGITAL DOWN CONVERTER With two modes of operation Pentek Inc.’s Model 7153, four-channel, high-speed digitizer PMC module is designed for processing baseband RF or IF signals from a communications’ receiver. It exhibits a signal-to-noise ratio of 75 dBFS and a spurious-free dynamic range of 87 dBc at a 70 MHz input frequency. The Model 7153 offers two modes of operation and has four embedded power meters that continuously monitor the average output power of each DDC channel. Pentek Inc. http://designnews.hotims.com/23101-583

LATTICE TECHNOLOGY’S DIGITAL MANUFACTURING SOFTWARE XVL software bundles streamline productivity, efficiency, cost Lattice Technology’s new packages focus on streamlining the way engineers in manufacturing industries can perform digital mock-up, process documentation and animation, create interactive 3-D parts lists and convincing illustrations direct from 3-D data without requiring anybody to move from their existing 3-D CAD, ERP or PLM platform. The three packages combine existing XVL software tools and deliver immediate savings through discounts on package pricing over separate product list prices. Lattice Technology Inc. http://designnews.hotims.com/23101-584

WHITE ELECTRONIC’S 8 GB MULTI-CHIP PACKAGE Available at data rates of 667, 533, 400 Mbs The 8 Gb DDR2 SDRAM is a high-speed CMOS, dynamic random-access memory with pipelined, multi-bank architecture that allows for concurrent operation and provides high, effective bandwidth. Available at data rates of 667, 533 and 400 Mbs in commercial, industrial and military temperature ranges, this MCP provides an upgrade path for the 64M x 72 package that is used on applications such as integrated core processors and radar systems. White Electronic Designs Corp. http://designnews.hotims.com/23101-585

M AT E R I A L S / FA S T E N I N G

Higher Performance Linear Motion

SSAINT-GOBAIN PERFORMANCE PLASTICS’ MELDIN® 7000 Recognized by UL for flammability The Polymer Products Business of SaintGobain Performance Plastics has developed the Meldin® 7000 series thermoset polyimide materials. They are well-suited for uses such as in semiconductor equipment components, aircraft components and other areas requiring the Meldin® 7000 series materials’ superior electrical insulative, heat insulative, chemical resistance and wear-resistance properties. Saint-Gobain Performance Plastics http://designnews.hotims.com/23101-588

SSTOCK DRIVE’S NEW CATALOG Features more than 160 products Stock Drive Product’s new catalog D160 features the patented Shaftloc® rotating component fastening device which secures shaft-mounted parts, such as pulleys, gears and couplings, to inch and metric shafting. The catalog D160 features more than 160 Shaftloc® products. Stock Drive Products/Sterling Instruments http://designnews.hotims.com/23101-586

QUICKPARTS LAUNCHES DESIGN SERVICE Free for customers working on Quickparts’ projects The new DFM service allows customers to take advantage of the vast manufacturing experience and knowledge of the dedicated Quickparts’ manufacturing team. The service (valued at $300) is offered free to customers working with Quickparts on new rapid prototyping and injection molding projects. A comprehensive DFM report is available which includes process flow details, expectations for the build and final DFM recommendations. Quickparts.com http://designnews.hotims.com/23101-587

SSOUTHCO®’S NEW H3 SWING HANDLE LATCHES Feature die-cast zinc housings for corrosion resistance Available in 25 x 125 mm and 25 x 150 mm sizes, Southco® H3 Swing Handle Latches offer a choice of direct drive handle for single- and multi-point applications, as well as gearbox-drive for multi-point latching. Mounting options for either drive-style permit clockwise and counter-clockwise handle rotation. All feature die-cast zinc housings for corrosion resistance, and satin chrome or black powder-coated finish, with custom color powder-coated also available. Southco® http://designnews.hotims.com/23101-589

Electromechanical Linear Actuator, EGC EGC actuators’ optimized profile design delivers increased rigidity and efficiency. The new EGC linear actuator provides: • speeds up to 5 m/s • accelerations up to 50 m/s2 • feed forces up to 2500 N • moment loads up to 1820 Nm • strokes up to 8.5 m Supporting advanced automation... as no one else can. For more information visit: www.festo.com/us/egc/dn

MOTION CONTROL

THINGAP®’S TGB1710 BRUSH MOTOR Features smooth, controllable power The 1.7-inch diameter by 3.3-inch long TGB1710 brush motor delivers 160 oz-inch peak torque and 183W continuous power, yet weighs only 22 oz. The ruggedized brush configuration design withstands the high vibration of portable tools. Brush life is longer than conventional motors because of its design and the inherent low inductance architecture of the motor coil. The TGB1710 motor also features smooth, controllable power due to its zero cogging and hysteresis torque. ThinGap® LLC http://designnews.hotims.com/23101-591

SIGUS®’ XIROS BALL BEARINGS Available in varying shaft diameters, high temperature resistance igus®’ Xiros ball bearings are made from the company’s high-temperature material iglide® A500 and are corrosion-free. Available in stainless steel and glass, they come in varying shaft diameters and are temperature resistant up to 302F. Xiros bearings can be used in medical, chemical, food, pharmaceutical, biotechnical and plant engineering. igus®’ polymer ball bearings are available from stock and can be used in combination with potentially corrosive chemicals. They do not require lubrication, making them compliant with food industry standards. igus® Inc. http://designnews.hotims.com/23101-590

TSAS AUTOMATION’S FOUR NEW COLLISION SENSORS Prevents damage to parts, tooling, machinery SAS Collision Sensors come in four different configurations to best meet different tooling and manufacturing environments. Collision Sensors send a signal to stop the robot when it detects an obstacle — to prevent costly damage to end effectors/end-of-arm tooling, parts and machinery. SAS Automation LLC http://designnews.hotims.com/23101-592

SWAGO’S 750-645 VIB I/O Tracks machine vibration conditions WAGO’s Vibration and Roller Bearing Monitoring Module (VIB-I/O) tracks machine vibration conditions. Based on ISO’s 10816-3 mechanical vibration standard, the 750-645 VIB-I/O’s channels monitor and analyze vibration severity and shock pulse feedback using WAGO’s 750-925 Tandem-Piezo acceleration sensor. WAGO Corp. http://designnews.hotims.com/23101-593

POWERLINK connection for their devices which requires few components, with overall costs below those of an ASICbased solution. B&R Industrial Automation Corp. http://designnews.hotims.com/23101-596

MOTION CONTROL, Continued

STRUST AUTOMATION’S TA602 MOTION CONTROLLERS

SEST’S AEGIS SGR SPLIT-RING BEARING PROTECTION KITS™ Provides clearance, protects bearings from electrical damage Developed for field installation without disassembly of coupled equipment, AEGIS SGR Split-Ring Bearing Protection Kits™ are designed to provide clearance for shaft shoulders, slingers and end-bell protrusions while protecting bearings from electrical damage caused by circulating or shaft currents. Standard-size kits fit NEMAframe motors with shaft diameters from 0.625 to 3.375 inch, as well as IEC frame motors with shaft diameters from 19 to 95 mm. Custom-size kits are also available. Electro Static Technology http://designnews.hotims.com/23101-594

Optimizes performance, reliability of motion systems New from Trust Automation is its board level 2- and 4-axis motion controller cards with dual processors. The TA602-D01 and D02 board level controllers can be used with brushed, brushless and stepper motor drives to optimize the performance and reliability of motion systems, especially in host communication, general I/O and high-speed micro-controller applications. Design time can be shortened with the ability to plug into a standard 2-mm header connector on the driver board. Trust Automation Inc. http://designnews.hotims.com/23101-595

B&R INDUSTRIAL AUTOMATION’S MICROCONTROLLER UNIT Ensures response times below 5 µs The microcontroller unit combines a 32 bit ARM9 CPU, 96 kB SRAM, Flash storage capacity between 512 kB and 2.1 MB, an Ethernet controller and a realtime clock. The solution ensures response times below 5 µs. Port’s stack and ST’s hardware allow users to implement a

SR+W AMERICA’S ULTRA-SMALL MK1/0.5 BELLOWS COUPLINGS Compact, high-precision R+W has completed its range of miniature bellows couplings with the ultrasmall MK1/0.5. Utilizing a formed bronze bellows, these couplings compensate for misalignment and transmit angular position, torque and velocity with a high level of accuracy even at very high speeds (100K+ rpm models available). The MK1/0.5 has a torque rating of 7 oz-inch within an outside diameter of 6.5 mm (0.256 inch). Custom bore sizes are available ranging from 1 to 3 mm (0.040 to 0.118 inch). R+W America L.P. http://designnews.hotims.com/23101-597

ANALOG/POWER MANAGEMENT

High Lighting

EFFICIENCY Green initiatives drive advancements in lighting technology BY RANDY FRANK, CONTRIBUTING EDITOR VBUS

“Incandescent bulbs aren’t cool anymore,” quips Stephen Bowling, technical staff engineer with Microchip Technology’s Application Segments Group. The statement pretty much summarizes why alternative light sources are receiving so much attention these days. Green initiatives and the drive for lower power consumption have made traditional incandescent bulbs the target of several companies with alternative technologies. “One of the challenges we have with all the green initiatives coming down the road is that designers of lighting systems are worried about system efficacy,” says Bowling. “Efficacy being the efficiency of the light source, so, how much electrical power do you put in it and how much light do you get out of it.” See sidebar Efficacy versus Efficiency, page A2. High intensity discharge (HID) lamps, a type of arc lamp, are commonly used in industrial warehouse or stadium lighting because they offer high power and high efficiency. A power supply maintains a constant arc to a lamp to produce light output. “There are some challenges in controlling those lamps,” says Bowling. The challenges are slow turn on and turn off times and limited dimming capability. Because they have both high efficiency and high power capability, HID lamps are finding applications in cars. Xenon headlights used on high-end vehicles are a form of high-intensity discharge lamps. Other apVin 5 V

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C5 R4

TPS61500

PWM

OVP

DIMC

FREQ

PGND

AGND

PGND

DL1 3W LED

DL2 R2

DL3 DL4

Texas Instruments’ TPS61500 can be used for analog dimming applications, as well as pure PWM brightness dimming, providing design options for lighting.

[ w w w. d es ig n n e ws.c o m]

PIC16HV785 Digital IO Int OSC 5V Reg.

CPU

Voltage Ref. +

OA1 +

–

BOR

COMP1

–

PWM

MCP1402 LED String

OA2

– +

COMP2

10-Bit ADC

MCP9700 Analog Temp Sensor

–

Microchip’s PIC16HV785, a mixed-Signal MCU with analog peripherals and additional analog components, supports a variety of lighting designs. The MCP1402 is a 500-mA, high-speed power MOSFET driver with a non-inverting output that controls an LED string based on input from the MCU.

plications for HID lamps can be found in LCD projectors and rear-projection television technology. “They’re actually one of the higher efficiency sources,” says Bowling. Because of their high efficiency, fluorescent and compact fluorescent lamps (CFLs) have become a good alternative to incandescents. According to the Dept. of Energy, CFLs can save as much as 75 percent on energy while lasting as much as 10 to 20 times longer than incandescent bulbs. However, they are not getting the attention of light emitting diodes (LEDs), a solid-state solution for lighting. “The Department of Energy (DOE) and other sources have done a lot of testing on LEDs and a lot of research and the projections for LED efficiency are much greater than you would see for current fluorescent technology, which is very mature,” says Bowling. HID lamps are also quite mature. In contrast, LED technology appears to be the hottest, or more appropriately, the coolest lighting technology based on the rapid improvements that are occurring. “Every day you see a press release from the major LED manufacturers saying that they have

A P R IL 2 0 0 9 ANALO G/ P O WE R MANAGE ME NT / A S P E CIAL E DIT O R IAL S E CTI ON A1

ANALOG/POWER MANAGEMENT made a new efficiency increase in the lab,” says Bowling. For example, in late 2008, Cree announced it achieved industry-best reported R&D results of 161 lm/W for a white power LED. While this is in the lab, high-volume production units exceeding 114 to 122 lm/W were available later in year. Compared to DOE numbers of 47-64 lm/W (including driver losses) reported as of October 2007, this is a remarkable improvement in one year.

Light Source

Typical Luminous Efficiency Range in lm/W (Varies Depending on Wattage and Lamp Type)

Incandescent (No Ballast)

10-18

Halogen (No Ballast)

15-20

Compact Fluorescent Lamp (CFL) (Including Ballast)

35-60

Linear Fluorescent (Including Ballast)

50-100

Metal Halide (Including Ballast)

50-90

Zeroing in on LEDs

Cool White LED 5000K (Including Driver)

47-84*

Typically, LEDS have been used as indicators, indicator lights and backlights in products with smaller displays such as cell phones, but new applications are emerging. “One of the major trends is in the television space, where LCD televisions are starting to use LED products for the backlight,” say Susie Inouye, research director, principle analyst, Databeans Inc. The market research firm recently published its 2008 LEDs report. Large screen LCD televisions require a very large matrix of LEDs making this a major trend driving higher volumes of LEDs. “The other thing that is going on is high brightness LEDs,” says Inouye. “The technology is getting to the point where we can actually use these products for (something) other than Christmas lights.” According to its 2008 LEDs report, in 2008, 61 billion

Warm White LED 3300K (Including Driver)

25-44*

Efficacy Versus Efficiency If efficacy is not a word that rolls off your tongue as easily as efficiency, perhaps a terminology refresher is in order. Even the DOE thinks clarification is required and provides definitions and an explanation. Unlike efficiency, that is dimensionless quantity relating the input to the output power, force, torque or other quotients, efficacy involves a ratio with different units for the input and the output. In the lighting area, efficacy is the amount of light output in lumens versus the electrical power supplied in watts. A comparison of the efficacy of the most commonly used light sources easily identifies incandescent bulbs as the lowest efficacy.

LED units were shipped. Due to a reduction in costs this number is predicted to continue to grow 23 percent annually, on average reaching 175 billion units in five years. One of the factors impacting LED acceptance is its potential for very long service life — if the LED operates within the specified temperature range. “The operating junction temperature of the LED is going to have a direct impact on the lifetime of the fixture,” says Microchip’s Bowling. Microchip’s solution for optimum life uses a silicon IC temperature sensor to avoid excessive LED temperatures. The MCP 9700, an analog temperature sensor, is a linearized sensor that connects to an analog driver circuit or a microcontroller. “By monitoring that sensor, the designer can keep track of the ambient conditions,” says Bowling “They can also keep track of the LED junction temperature, which is very important to them.” Designers are using this approach because of programs like the DOE’s ENERGY STAR® Program for Solid-State Lighting. This is a voluntary standard but it appears to have acceptance

* As of October 2007

Green

Source: U.S. Dept. of Energy

Including LED driver losses that can detract from efficacy by as much as 15 percent, cool white and warm white LEDs were easily two to three times more desirable on the green scale as of October 2007. If the most recent LED performance was used, these values would be considerably higher.

from LED fixture suppliers. “Fixture designers are very interested in the specification and they are trying to adhere to it to ensure that they put some high-quality LED fixtures out in the marketplace that will be adopted and not have some of the shortcomings that the initial CFL products had,” says Bowling. Several other companies also addressed the challenges system designers face with a variety of approaches at the IC level. For example, to drive white LED backlights in medium- to large-format automotive TFT-LCD displays, ROHM Semiconductor introduced the BD8113EFV-E2, a dual-channel driver capable of up to 150 mA constant current per channel. Designed specifically for automotive applications, the driver IC can handle a maximum input voltage of 36V, with a supply voltage range of 5 to 30V, and a wide operating temperature range of -40 to 105C. Battery-powered applications, with small form factors, pose another challenge for driving LEDs. “System Architects must balance power consumption and long autonomy, that is battery life, to meet consumer expectations for device usage. It is not enough to simply boost the efficiency from 87 percent to 92 percent and hope for the best,” says Ken Marasco, system applications manager, Analog Devices. “To increase portable system autonomy, we must adopt intelligent methods of managing the WLED brightness based on display content and ambient light intensity.” Analog Devices’ ADP5520 adaptive lighting management system is one such product that allows the system architect to intelligently increase power system efficiency by allowing the device to automatically monitor ambient light levels and adjust LED brightness according to changes in the ambient lighting environment. Further power consumption reduction is achieved by automatically adjusting the WLED drive voltage to match the actual forward voltage of WLEDs used in the device. “This type of integrated architecture saves energy by minimizing the required CPU processing for ambient light monitoring and LED brightness control, reducing current drain on the battery and increasing available processor bandwidth,” says Marasco. Sensing ambient light to optimize LED operation that oc-

A2 ANAL O G/ POWE R M A NA G E M E N T / A S P E C I A L E D IT O R IA L S E CTIO N AP R IL 2 0 0 9

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ANALOG/POWER MANAGEMENT curs as an integral part of the ADP5520 is another one of the growing power-saving approaches. Many suppliers offer a stand-alone ambient light sensor (ALS). Databeans estimates the current total available market (TAM) for ALS at 7 percent of LED revenue, or roughly $327 million worldwide. “Due to the large number of feature-rich phone products that will drive demand, we expect this revenue to grow at a compound annual growth rate of 21 percent each year over the next five years to reach close to $860 million by 2014,” says Databeans’ Inouye. National Semiconductor attacked another lighting design problem, flicker-free dimming of high-brightness LEDs, with a conventional TRIode for Alternating Current (Triac). Dimming an LED bulb using a Triac wall dimmer does not yield optimal dimming performance because the commonly used TRIAC wall dimmer requires a resistive load and an LED bulb does not appear as a resistive load to the Triac. With the LM3445 TRIAC dimmable LED driver, a full 100:1 range of dimming capability is possible while delivering more than 1A of constant current to large strings of LEDs. This provides a dimming solution for residential, architectural, commercial and industrial applications. Texas Instruments’ TPS61500 high brightness LED driver also provides dimming capability, while achieving 93 percent efficiency. With an integrated power switch rated up to 40V,

the TPS61500 can control LED strings drawing up to 3A in signage, ambient light, office light, general illumination, military, medical and sensor applications. This current level can drive four 3-W LEDs from a 5-V input or eight 3-W LEDs from a 12-V input. Choices for going green with LED lighting are certainly proliferating, so system engineers need to constantly lookout for solutions that most closely match the requirements of their latest project. For More

information

POWER MANAGEMENT

CFLs can save on energy and last longer than regular bulbs: http://designnews.hotims.com/23101-608 Cree achieved industry-best reported R&D results for a white power LED: http://designnews.hotims.com/23101-609 Databeans’ 2008 LEDs report: http://designnews.hotims.com/23101-610 DOE ENERGY STAR® Program for Solid-State Lighting: http://designnews.hotims.com/23101-611 Analog Devices’ ADP5520 adaptive lighting management system: http://designnews.hotims.com/23101-612 National Semiconductor’s LM3445 TRIAC dimmable LED driver: http://designnews.hotims.com/23101-613 Texas Instruments’ TPS61500 high brightness LED driver: http://designnews.hotims.com/23101-614

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3/10/2009 1:21:29 PM

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CALAMITIES

The Case of the Spurious Spring Replacement kickstand part causes scary spill on modified motorcycle A YOUNG MAN TOOK HIS MOTORCYCLE FOR A SPIN.

He started to navigate a gentle left-hand turn (about a 1,000 ft radius), lost control of the bike and piled up. He was injured badly enough to sue. I was retained by counsel for the bike manufacturer. THE INVESTIGATION

The spring on the kickstand was found to be missing after the accident. The operator claimed the absence of the spring caused the stand to drop down and distract him, causing the accident. The configuration of the motorcycle was such that the end of the dangling stand could not touch the surface of the road. The bike had gone through several owners and was extensively modified prior to the accident. The plaintiff claimed to have replaced the spring a couple of days before the accident. The figure, above right, shows an exemplar spring obtained from a dealer. The hooks are separate pieces that are held inside the tapered ends of the spring by so-called spades. The threepiece construction is clearly superior to a one-piece spring. The stress in the spring depends crucially on the number of coils and diameter of the wire. In later versions, the number of coils were increased and a lighter wire used. Both changes would make for a longer spring life. The bike manufacturer claimed to have had no trouble with spring 74

D E S I G N N E W S A P R I L 2 0 0 9 [ w w w. d e s i g n n e w s . c o m ]

KENNETH RUSSELL PROFESSOR EMERITUS, MIT CAMBRIDGE, MA

Tr u e S t o r i e s

fracture; however, the number of springs being sold and design modifications suggested otherwise. Structural parts subjected to cyclic stresses must be designed to withstand so-called fatigue loading. Design may be for high-cycle fatigue or low-cycle fatigue. Engine parts such as connecting rods must withstand many millions of cycles, which constitutes high-cycle fatigue. Many other parts are subjected to so-called low-cycle fatigue, which involves only hundreds or thousands of stress cycles. Lowcycle fatigue loading is intermediate in severity between static loading and high-cycle fatigue. It was fairly easy to calculate the stresses in the spring from the spring geometry and extension during use. Calculations showed the spring to be suit- This kickstand spring, obtained from a motorcycle dealer, shows what the spring able for low-cycle on the young man’s motorcycle should use, but not high have looked like. cycle. The kickstand had only been used a few times between the installation of the new spring and the accident, which is clearly very low-cycle fatigue. It was entirely possible we were barking up the wrong tree in examining the springs from the manufacturer. There was no record of the plaintiff having bought a spring from the local dealer. The plaintiff ’s father said his son got the replacement out of a box of springs. THE SMOKING GUN

The father’s comment rang a bell with me. I kept old cars running for many years and still do much of the maintenance and repairs on my house. I have several boxes labeled “doodads” which contain various bits of hardware that may be of some future use. Faced with a missing spring I would have grabbed some kind of a replacement and tried to make it work. I suspect the plaintiff did something similar. I reported my findings to my client, but never testified. My client reported he won on a matter of law rather than evidence, but did not give me any details. The plaintiff appealed the verdict and my client expected the appeal to be upheld and for the case to go to trial. This was the last I heard of the case, which I suspect was settled out of court for a small amount.

Ken Russell (kenruss@mit.edu) is professor emeritus of Metallurgy and Nuclear Engineering at MIT. He specializes in physical metallurgy, forensic metallurgy and failure analysis. Cases presented here are drawn from his actual forensic files. Illustration: Daniel Guidera

T H E G A D G E T F R E A K ® F I L E S

C A S E

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Monster Power Blender is Sweetly Green

䊳 For complete schematics and build instructions, go to www. designnews.com/GadgetFreak. 䊳

To view the Gadget Freak archives, go to www. designnews.com/gfarchives.

Check out Gadget Freak Case #134: Chris Knew the Secret to a Great Martini This custom-machined top fuel blender, built from junk parts, kicks even the most mundane cocktails into overdrive. http://designnews.hotims. com/23091-626

ick Crammond created a turbine blender using the principles of Nikola Tesla. The Tesla blender achieves accelerated performance by combining water and air pressure simultaneously to the turbine nozzle. The blender is fueled by an off-grid, self-contained, solar-powered, re-circulating fluid system. The Tesla blender is green in its power use and made from recycled parts. Crammond incorporated solar, battery, electric, hydraulic, pneumatic, magnetic and mechanical systems into a powerful conglomeration. Check out the Power-Boost Blender in action at

www.designnews.com/GadgetFreak

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