Revolve Magazine 2022 Issue 2 by Revolve NTNU

MAGAZINE

ISSUE 2, 2022

REVOLVE

Contents 4

RevolveDagen

Kongsberg Gruppen

Bertel O. Steen

Inission

Shape Norge

Master Theses

Molstad Modell & Form

Tomra

4Test

Trondheim Stål

Our New Car

K. Lerøy

UMF

Get to Know Power Systems

Semcon

Mjøs Metallvarefabrikk AS

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Editor-in-Chief Mia Elisenberg T: +47 90 12 60 17 E: mia.elisenberg@revolve.no Project Manager Sigurd Werner-Torgersen T: +47 48 25 08 28 E: sigurd.wernertorgersen@revolve.no

Cover Photo By: Tond He

Head of Marketing & Finance Aida Angell T: +47 93 09 99 29 E: aida.angell@revolve.no

Graphic Designer Mia Elisenberg T: +47 90 12 60 17 E: mia.elisenberg@revolve.no

Mia Elisenberg Editor-in-Chief 30

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2022 is a special year for Revolve NTNU. We are producing our 10th car! In this issue, you’ll get to know the details of our new car and see how much has changed since our first car, KA Borealis R, was produced in 2012.

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Revolve NTNU E: post@revolve.no Revolve NTNU, S. P. Andersens veg 3, c/o MTP Valgrinda, 7031 Trondheim, Norway 3

REVOLV E DAG E N Vårild H. I. E. Øyulvstad Event Manager

Revolve NTNU has a long tradition of showcasing our work and highlighting our partners. In order to give our sponsors the best opportunities to meet relevant students at NTNU and promote their business, we arrange RevolveDagen (the RevolveDay) at campus Gløshaugen. RevolveDagen is a career day with many aspects. It exhibits Revolve NTNU’s work for students, increases our presence at campus and most importantly: the students get to know the sponsors that make our project possible. The event takes place at Elbygget (one of the buildings at campus Gløshaugen).

Throughout the day, company presentations from Kongsberg Gruppe, Bertel O. Steen, BDO, Hydro, Kongsberg Automotive and EY Skye were held. This year, we were also lucky to have a representative from Microsoft visit us and hold an engaging presentation on artificial intelligence. During the presentations., prizes and other goodies were handed out. Some of the students also got the opportunity to secure themselves summer internships and full-time positions by taking part in speed interviews. Our very own driving simulator, our 2016 car Gnist, was just as popular as always. With the help of a scoreboard, we also awarded the top three drivers of the day.

This year’s career day has given us both challenges and accomplishments, but most of all it connected Revolve NTNU and the participating sponsors. The day wouldn’t have been possible without the incredible participation and problem solving skills of this year’s team. RevolveDagen 2022 gave everyone who participated, both sponsors, students, employees at NTNU and team members, many memorable moments that will stay with us in the future.

F ROM E XCE LL EN T PE R FO RM AN L AND TO E X TR EM E P ER FO RM A SEA AND I N TH E A I R

Revolve NTNU and Kongsberg Gruppen (KONGSBERG) have a long history together. KONGSBERG has been by our side since 2013, and without them, making a race car would not be possible. Throughout the years, Revolve NTNU has helped accelerate its members’ careers, resulting in many of them securing internships and work positions at valuable companies, such as KONGSBERG. Jan Ottar Olsen is one of these. He studied Energy and Environmental Engineering (MSc programme, 5 years) whilst being a part of the group Embedded Electronics. The Embedded Electronics group designs advanced PCBs that are being produced at an industry-level, and they test and tune analog and digital circuitry. They also work with embedded software on ATSAM microcontrollers and FPGA systems. In 2019, Olsen was responsible for the Battery Management

Systems (BMS), and in 2021, he was one of the people responsible for further development of Revolve NTNU’s inhouse developed inverter. One of Olsen’s favourite moments from the 2019 season was competing at Formula Student Austria (FSA), which is considered the second highest level competition after Formula Student Germany. He recalls the first day of the competition fondly. This was when the Accumulator Scrutineering event took place. The car’s accumulator (battery pack) is the most safety critical system on the car. At this event, the team had to convince the scrutineers (judges) that their design was safe, designed well and rules compliant. People ran around and shouted at each other in the Formula 1 pit area, looking for tools, equipment and documents, whilst he was sitting peacefully at a small table in the midst of the chaos. With a soldering iron in 6

one hand and a scalpel in the other, he looked through a microscope and worked with excellent precision. As for the 2021 season, he had a great time testing the inverter together with his fellow inverter developer Eskil A. Mogstad. They spent uncountable hours designing, planning, assembling, debugging and testing the new system. They truly felt like mad scientists whilst pushing the system to its full potential! All of this resulted in them being able to make the motor spin, in a controlled manner, at 20.000 RPM at 600 V DC, which was exactly the proof of concept they needed. It’s an understatement to say that the experience Olsen gained whilst being a part of the team was unique and invaluable. This also made him able to effectively get started in his new job at KONGSBERG.

N CE O N A NCE AT

Today, he works for KDA at Division Missile (DM), specifically in the group eWorks at Kjeller in Norway. eWorks is the department for electronics R&D in KDA, and is the organizational part of DM. eWorks contributes in projects/products for all divisions in KDA: Divisions Missile Systems (DM), Division Land Systems (DLS), Division Integrated Defence Systems (IDS) and Division Space & Surveillance (DSS). eWorks have locations in Kongsberg, Asker and Kjeller.

At eWorks, Olsen takes part in the certification process of the safety modules in one of the missiles, as well as planning, executing and documenting the testing. The Embedded Electronics experience in the process of designing, testing, debugging and verifying circuitry earned him the advantage of being able to start working at eWorks right away, with little to no need for training. This made the transition from developing a race car to developing larger and more complex systems smooth and effective.

Revolve NTNU is proud of how we help our team members learn new skills, hone their crafts and accelerate their careers. The majority of us start out as engineers-in-the-making, but by the time we leave the team, we’ve gotten a solid kickstart on our way to becoming world-class engineers. We are incredibly thankful for the help and support provided by KONGSBERG to make all of this possible, and we’re excited to see what the future holds for our partnership.

Mia Li Elisenberg Graphic Designer

Jan Ottar Olsen

KDA at Division Missile, eWorks

RACIN G I NTO TH E AU TO M OTIV INDUS T RY O F TO MO RROW

The automotive industry is facing an interesting and challenging future, with some of the largest shifts in its history ahead. Making use of big data and optimizing customer experiences will be the new standard. Bertel O. Steen is taking part in building the mobility of tomorrow by developing smart and sustainable solutions that make life easier. They are actively leading the industry into this future by developing their services Otto and Fleks. On a sunny day in March, we sat down with Are Hjelt and Olav Falck-Pedersen at their office at Solsiden, Trondheim. With Spring comes new beginnings, and Bertel O. Steen is taking the automotive industry into the beginning of a new

era. When envisioning the future of cars, Hjelt believes people will favor car sharing and car subscription models over owning their own car. With a focus on sustainability and increasing our everyday mobility, Bertel O. Steen is offering the car sharing service Otto. Otto is as easy as one-two-three, and by removing all pain points in the user experience, the service lets the customer focus on what really matters: getting from point A to point B. The overall market for such a service is still in its early days, but there is a clear need for this in the larger cities. With sustainability in mind, Otto strives to offer as many electric cars as possible, but here come the challenges: increasing the number of cars requires 8

more parking space, and increasing the number of electric cars requires a greater availability in charging stations. These barriers might be challenging now, but in the future, the infrastructure will be evolved to accommodate car sharing services. When that happens, Otto will be more than ready. While developing such a new and innovative service as Otto, facing technical challenges is inevitable. Data is the gold of the future. Being able to collect, analyze and make use of car data opens up for great opportunities. What if your car could predict the next time you need to clean it? What if your car could predict the next time it needs service and automatically book the appointment for you? When looking

further into the future, Hjelt finds autonomous vehicles especially exciting. With great data handling and autonomous vehicles, the service possibilities seem endless! In order for Bertel O. Steen to provide reliable cars at excellent standards through all their services, they need skilled employees. At their office, we also sat down with intern Olav FalckPedersen. He is currently writing his Master thesis in Industrial Economics and Technology Management on car sharing and has had various technical positions prior to his internship at Bertel O. Steen. Now, he is working at the department of Data & Insight doing data analyses and working with machine learning and development, as

well as economics. To him, applying for an internship here felt natural, as the position allowed for combining skills in both tech and economics. Falck-Pedersen’s internship lets him be a part of the whole development process from start to finish. Also, he has the freedom and opportunity to try to solve tasks in various ways, and Bertel O. Steen provides him with the trust and guidance needed to make sure the solutions he makes are both innovative and reliable. The effective communication both internally and across departments makes them all able to solve issues fast, which in return rewards the team with solid progress.

Bertel O. Steen is not just about cars; they are so much more than that. They are riding the technological wave that will take the automotive industry to a new level, and they know data handling will be a key factor in making this future the best it can be. We’re talking about machine learning, big data, web services, development, and steep, but highly rewarding, learning curves. Working at Bertel O. Steen’s departments for Data & Insight is a great opportunity for taking the first step into the automotive industry of tomorrow.

Mia Li Elisenberg Graphic Designer

Photo: Trond He (Revolve NTNU)

Niklas Strøsnes

Group Leader for Embedded Electronics

Since the first days of Revolve NTNU ten years ago, Inission Løkken has been a key part of the design, production and testing of our self-developed PCBs. Located at the beautiful Løkken Verk in Trønderlag, we in Revolve NTNU have a magnificent production facility with a great team of engineers and machine operators ready to support us just a short drive out from Trondheim.

product only increased when we pivoted to the electric race car we’ve made since, which was a challenge they were more than willing to help out with. With more than 30 years of experience in the electronics manufacturing industry as individual companies before the merger, are very helpful with guiding us with design when needed and through the entire production process.

As one of the world’s only total suppliers, Inission helps their global customers with end-to-end services in electronics manufacturing, providing everything from design and development, thorough stress testing and even the final distribution to the end customers. As they usually make products to the standards of space or deep waters, their competence suits us nicely when we’re trying to build a fast and robust formula race car.

Each spring, we pack up all our electronic components and head out to Løkken Verk with a group of 4-5 people and stay for as long as we need to produce all our PCBs. This is typically a time consuming process of about two weeks, as we have more than more than 40 self-developed PCBs on our car and need a few backups for each of them. The team awaiting us there are always welcoming and helpful, such as going out of their way to help us fix some rather suboptimally produced PCBs we had from earlier. We’re always looking forward to coming back - not to mention the great lunch we get there! After all our components are placed on their respective pads and they’ve

Inission Løkken, previously known as Simpro, was already an important contributor to Revolve NTNU when we still made combustion vehicles in the beginning. Their relevance to our

been a round in their professional standard reflow ovens, we have the ability to borrow their test equipment as needed. As an example, we looked at some of our newly produced PCBs in their highly advanced X-ray machine to check for such as short circuits in the soldering points and components that aren’t placed properly, also known as components that are “tombstoned”. We are also able to use their vibration testing machine to simulate the rugged pavement we drive on and temperature chamber to simulate the temperature conditions to make sure we’re ready for both Norwegian and southern European climates. We are incredibly thankful for the great cooperation with Inission Løkken, and we are very much looking forward to many exciting years with them by our side!

Shape is an experienced producer of products that range from simple prototypes to state-of-the-art small scale machining of parts in aluminum and steel. Additionally, they provide services within reverse engineering and 3D-modelling. They are a futureoriented business and are reducing their material cost and increasing their ecofriendliness. Shape has been a sponsor of Revolve NTNU for many years and play an important role in the production of our race car. This year, they have produced our monocoque plug and core, as well as our aerodynamics core. We are proud of the high-quality parts Shape provides us with and are looking forward to continuing our partnership!

12 Photo: Shape

13 Photo: Trond He (Revolve NTNU)

DEEP DIVE

M ASTER TH ES ES Last issue, we delved deeper into the world of Embedded Electronics and Control Systems. This time, we are getting to know Embedded Electronics further, as well as taking a look at Suspension & Powertrain.

Sondre Audal

Suspension & Powertrain Suspension

Ola Flåskjer

Suspension & Powertrain Upright

Jostein Brovold

Embedded Electronics Sensors

MASTER x Understanding what we do not understand

Sondre Audal

Suspension & Powertrain Suspension

My name is Sondre, and I am responsible for the structural aspect of our suspension system, just like last year. I am writing my master thesis in mechanical engineering for Revolve NTNU, a dream ever since I first joined the team back in 2017. Being in the team for four years (2017, 2020, 2021, and 2022) has given me a great insight in different positions, from marketing and pedal box, to the structural analysis of the suspension system. Working with different cars, different people, and different challenges have made my days so very different, and rest a sure: no day is alike!

Here in Revolve NTNU, we aim to push the boundaries even further, every year. It is a part of our philosophy and DNA. We aim to gain that little extra performance out of the car, giving it the extra potential to run around the (sat up) tracks of Hockenheim and Hungaroring. There are many parameters to consider, which is partly why you need a team of over 60 engineers to be one of the best, but maybe the easiest parameter to measure, is weight. In order to push this parameter, you need to know what forces are acting on it. Me being responsible for the outboard suspension (A-arms, push, and tie rods), my main focus would be on how much force the tires generate, and how they would propagate through first our rim, then the gearbox, then the upright, before they all propagate through the suspension members. We have models for this, but we are not sure how reliable these models are – they are not validated, as we say. What more is that we have suspension brackets at that end again!

U N D ERS TANDI W H AT W E DO U N D ERS TAND For the suspension forces, we have, as aforementioned, three stages of propagation before the we see the final reaction forces and thus stress image on the parts. This means we have three stages of possible safety factors being applied. In fact, there were four, as the contact patch of the tire was unknown. This was my project thesis and during the post-season testing done in the latter days of September, allowed us to validate such. We ran Luna with minor modifications to allow measuring devices being installed. Such devices are really gains considering the amount of data we can collect, but due to the expensive nature of them, and the added weight and compliance, means they are not really suitable to be ran for competitions. The test which we ran, measured the loads going into our tie rod – both front and rear. These loads have a great correspondence with the trail of the contact patch, meaning the distance from the tire center, seen from the side view. This is quite an unknown, because the tire changes characteristics depending on the normal load, tire

pressure, ambient temperature, etc. So naturally, just getting a somewhat more reasonable number would be quite insightful. Up until then, we had just gone for a really conservative number, which would yield high bending forces in our suspension. The measured forces, compared to the simulations which was ran at different values, resulted in us having a more realistic model, with a trail value that made sense. Anyways. Three stages of safety factors means that each model’s safety factor is multiplied together, and then you would always yield some safety factor for the part itself. If we say the average safety factor for each propagation step is 1.15, that means the final safety factor is 1.15^3 = 1.52 even before you look at the part and can say “Well this part has a safety factor of 1.05” – whilst in reality it is more like 1.6!

MASTER Understanding what we do not understand

IN G N OT Figure 1: New Strain Design

As you can understand, this would yield a heavier car than necessary, something I am not a great fan of. My Master thesis is based around the overall safety factor of the suspension system – how much (or worse, less) does our propagation model estimate the forces going to our suspension brackets? To validate this, I have designed a new half-suspension for last year’s car, Luna. This suspension differs in that manner that the end parts of our carbon fiber suspension rods, are now extended and have an area where you would have more strain than usual, and over a larger area. These two factors combined yields them more optimal for strain gauging versus the original design. I will then apply a controlled amount of force in the rim (the tire being too random), and then to measure the strain in the rod ends. The strain will be converted into forces which then can be compared to the said estimation model we use. Thus, we can expect to see some deviations – we know that. What is interesting is to see the magnitude of the deviations. If they are massive, we know that the car

has potential to pushed even further in the weight saving area (with regards to yielding). If this proves to be a success, and the numbers makes sense, you could maybe see us running this suspension setup on our new car R22. This would be great with knowledge gained on how the transient handling of the car is, how the loads work going from one left hander into a right hander, from hard braking to hard acceleration. All of this is limited by the scope that the car is standing still in our workshop. The long-term objective would be that with the knowledge gained, maybe even we are able to somewhat validate our tire models. It is a long way to that, but with the limit-pushing nature of Revolve NTNU, you never know when this could happen.

MASTER x Designing milled aluminum uprights

Ola Flåskjer

Suspension & Powertrain Upright

My name is Ola Flåskjer, I am a fifth year Master’s student in mechanical engineering at NTNU. I am 24 years old and from Ålesund, Norway. With Revolve NTNU I am a technical member in the suspension group, responsible for designing the uprights. For me this is a very rewarding task, as you have a high degree of design freedom and get a lot of experience in 3D-modelling and finite element analysis. Revolve NTNU has provided me with a highspeed (no pun intended), learn-as-you-go experience and let me be a part of a dedicated group of people with similar goals.

Get to know the upright One of the main sources of performance loss in racing is component compliance. Compliance is the inverse of stiffness, and in a properly tuned race car, represents a deviation from the optimal position and a loss of lateral acceleration. Structural components, therefore, need to provide adequate stiffness to minimize performance loss. In a power-limited car, such as the cars in Formula Student, governed by a strict rule set, a low mass is also of the utmost importance. A formulation of the dimensioning objectives of suspension components should therefore include both stiffness and mass. One such component is the upright which is essentially a multi purpose bracket which transfers the load from the wheel bearings into the suspension geometry. All forces originate in the tires contact patch, and load is therefore mostly undampened when it reaches the upright. The resulting load cases, which stem from the car’s behavior during

D E S I G NI NG M I A LU M I NU M UPRI G H T S driving, are dynamic and complex. The uprights are directly fastened to the motors and our hub-mounted planetary gearboxes, where it acts as the carrier structure of the planetary gears. Reactionary forces occurs at the planet pin mounting points. Additional loads are supplied from mechanical breaking, as the cars calipers are mounted directly to the upright aswell. The upright, as the main structural component in the wheel assembly, significantly contributes to compliance about the x- and z-axis of the tire, known as camber and toe. The project thesis aims to establish, and design in accordance to, concrete camber and toe stiffness goals. Such goals, based on a complete overview of the entire suspension system, are established for each of the car’s four uprights. All systems connecting the car to the ground, from the tires, hub, upright, all the way to the structural suspension and monocoque, are connected in series. A chain made up of individual links connected in series will break at its

weakest link. Likewise, the compliance in the suspension system is largely determined by its most compliant member. Since mass and compliance are often inversely proportional, having overly stiff single components will contribute little to overall stiffness, while negatively impacting weight. Some components, like the monocoque and rims, are difficult to modify and their compliance contributions to the suspension are more or less set. If the compliance contributions of such parts are high, these will become natural stiffness targets for other more easily modifiable parts. This year, the goal for the whole suspension group has been to standardize our FEA models and establish common global stiffness goals. Simulated compliance is regularly updated, and individual component stiffness goals can be determined by using the expression for the spring constant for a springs-in-series system. In previous seasons the main focus has been dimensioning for camber stiffness, with less concern for toe compliance.

MASTER Designing milled aluminum uprights

IL L ED Figure 3: Front Left Corner Assembly

Figure 2: FEA simulation setup.

Figure 1: Raw topology result.

Changing tires from the Continental 205/470R13 to Hoosier LC0 with a far lower camber sensitivity, toe compliance becomes a vital design parameter. Targets of 25 kN/deg and 24 kN/deg for front and rear camber compliance, and 40 kN/deg and 55 kN/deg for front and rear toe compliance were established and subsequently used in topology optimization. These targets were introduced as constraints in the optimization, together with a volume target and minimum strain as the objective function. The volume targets where subsequently reduced, until the model was no longer able to converge for the given compliance constraints. Ultimately, such an approach should yield a structure that is both stiff and lightweight. The results were accurate to the chosen constraints, and a preliminary mass reduction of 311 grams in total was achieved before CAD reconstruction. After CAD reconstruction, the total weight saved from the previous year was 430 grams with stiffnesses of 38 kN/ deg in camber and 37 kN/deg in toe for the front uprights, and 31 kN/deg in camber and 50 kN/deg in toe for the rear uprights.

The Master’s thesis aims to determine a more complete overview of compliance and mass influences on cornering speed, as well as testing the machined uprights to see if the theoretical FEA results are accurate. Validating such analyses gives invaluable insight for future part design, and will provide evidence whether or not the models we are using are representative of reality. Testing parameters such as compliance is difficult to do dynamically during driving, and simplifications will need to be performed in order to test statically. The main concern will be to perform test that best represents the load cases that the tire is subjected to. Autumn testing with a load cell in the tie rod has already provided some insight into what forces occur here. This data has been used to verify propagated simulation forces in our FEAmodels in the tie rods during cornering load cases. The ultimate long-term goal will be to gain enough of an understanding of the car to design the entire suspension in accordance to the limitations of the tire. In this scenario, every part in the chain will have a similar stiffness, with no glaring weak links and performance leakages.

MASTER x Wireless Research Project

Jostein Brovold

Embedded Electronics Sensors

I am 23 years old and come from a place called Hønefoss just north of Oslo. This is my fourth and final year in the Embedded Electronics group in Revolve NTNU. I have previously worked with the safety systems, battery management systems, low voltage supply, and sensors in both the DV (Driverless Vehicle) and EV (Electric Vehicle) racecar. Writing my master thesis allows me to fully focus on the project and develop a system from idea to implementation.

New technology This year Revolve NTNU is running a research project for wireless technology use cases in the racecar. Previously, all of the embedded systems have communicated through wired technologies like CAN, SPI, USART, RS485, but this year we are looking into wireless technology to replace some of these communication protocols. My project is to develop a system that allows for sampling of sensor values and transmitting them a broadcaster through protocols like Bluetooth Low Energy. In my project thesis this spring I developed the SBS Master (Sensor Broadcasting System Master Controller) shown in Figure 1. The SBS Master features an ATSAME70N21B for processing sensor data, and an nRF52832 from Nordic Semiconductor. The nRF52832 System on Chip shown in Figure 2 features a 64 MHz Cortex M4 ARM processor and a 2.4 GHz radio. The radio allows for

W I RE L E S S RE S PROJ ECT data to be sent using a custom protocol or with BLE by using their SoftDevices. The nRF uses Binary Phase Shift Keying to encode data up to 2 Mbps, plenty for small sensor usecases. The nRF52832 is connected to a selfdesigned inverted-f antenna as shown in Figure 3. The antenna is designed and simulated in ANSYS Electronics. This allows for tuning of PCB stack-up and antenna dimensions to get the most performance out of the nRF52832. The simulated antenna has a bandwidth of 200 MHz and a max S11 of -13 dB. For my Master thesis, I will be developing a custom software protocol that allows for transfer of data between nRFs. The protocol will be running in a Shockburst mode where data packets are sent out at set intervals. The receiver will ack (acknowledge) these data packets with new settings and transmit the data to the ATSAME70 using SPI.

Currently, we are looking into using wireless technology for the battery management system, where one nRF52832 would gather data from the LTC6811 battery monitoring chip, and transmit them to the AMS master using the custom protocol. Other use cases are outboard by the motors and the wheel. This would allow for only routing power out to the wheels and gathering data from the encoder, temperature sensors, accelerometers, and transmitting them to the SBS Master using the wireless protocol.

MASTER Wireless Research Project

SEA RCH

Figure 2: nRF52832 SoC from Nordic Semiconductor (source: https://www.nordicsemi.com/Products/nRF52832)

Figure 1: SBS Master.

Figure 3: Inverted-f antenna. 21

MOLS TA D MO D EL L & FO R M We love a good challenge. If you have a problem you need to solve, it is a good idea to ask for help from someone who never gives up. We are experts in making molds for rotational molding and thermosetting plastics. We also make foundry patterns for all types of metal casting. In our polyurethane department, we produce various types of plastic products for demanding customers all over the world. If you have a cable that must be protected against wear and tear or a fish farm that is to be anchored, you can come to us for help. In 2022, we have once again delivered parts to Revolve NTNU. This time we have milled out foam cores to be able to cast body parts for the car. We wish Revolve NTNU the best of luck with this year’s project.

TOMRA R1 – Making recycling more WOW.

INNOVATE FOR TOMORROW:

JOIN TOMRA TODAY Like many world-leading technology companies, TOMRA was founded in a garage. This garage wasn’t in Palo Alto, though, it was in Vollen, Norway… 50 years later, as the largest provider of reverse vending machines (or “panteautomater”) on the planet, TOMRA Collection strives to reduce society’s reliance on raw materials by enabling drink bottles, cans, and other packaging to be continually recycled in a closed loop. TOMRA is built on innovation. In 1972, brothers Tore and Petter Planke created a solution to a problem: a local shop owner wanted a machine that could quickly and easily take back empty bottles being brought to his store. This challenge led to the creation of the world’s first reverse vending machine, which collected 32,000 containers in its first 17 days of operation. Fast forward to 2022, and TOMRA Collection gathers over 40 billion containers each year, with installations in approximately 50,000 stores worldwide. What a journey! 40 billion containers might sound like a lot, but it’s actually less than 3% of what’s sold annually. Naturally, we’ve got our sights set on the remaining 97% and we’re looking for the brightest minds to help us get it. That’s why we’ve partnered with NTNU.

Sketches and maquettes of TOMRA’s multi-feed R1 reverse vending machine.

At TOMRA, we don’t just work with concepts or designs. We own the entire product development process from the earliest concept through to the final product, being produced in the thousands. Looking for digital development opportunities? No problem. Our digital products, including the myTOMRA mobile app, are used by hundreds of thousands of people across the globe every single day.

“I see ideas from our earliest product design sessions out in the world, making an impact. That’s special.” Kristian Hovde, Head of Hardware & Verification at TOMRA Collection 23

Norway is home to globally impactful technologies and NTNU nurtures a major innovation environment. At TOMRA, we thrive on opportunities to bring these worlds together, which is why we support projects like Revolve. They excite us, they inspire us, and they challenge us.

Come and challenge us. Explore open positions at tomra.com/nyehoder

24 Photo: Trond He (Revolve NTNU)

25 Photo: Trond He (Revolve NTNU)

ELD

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GNIST

20 16

VIL JE

20 15

LUNA

20 21

NOVA

ATMOS

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27 Photo: Trond He (Revolve NTNU)

Eskil Aaning Mogstad

Group Leader Control Systems

BAT T E RY T E S TI N G I N RE VO LV E NTN U P OWE RE D BY 4T EST I N S TRU M E N TS One of the essential parts of an electric vehicle is the battery accumulator. The battery is one of the three critical components of the electric powertrain, in addition to the inverters and the motors, and contains all the energy for the propulsion of the vehicle. Revolve NTNU has significantly focused on building up knowledge around battery technology in the last couple of seasons. The organization has accomplished several different projects

surrounding the battery pack, including a redesigned battery management system, investigating the impact of cooling methods on aging in the cells, and State of Charge and State of Health estimation. This year, we’re testing several new and exciting battery cells and comparing the data we acquire from testing them, in a search to find potential candidates for a future battery pack redesign. We’re especially interested in cells with high

specific energy and energy density. Being one of the heaviest systems in the vehicle, the potential for saving weight in the battery pack is huge, even with slightly lighter weight cells.

Figure 1

Figure 2

Using the Hioki BT4560 battery impedance meter, we’ve measured the internal impedance of the battery cell at different frequencies. Using the frequency sweep functionality of the instrument has allowed us to generate plots of the resistance against the reactance across frequencies, as can be seen in Figure 1. The figure shows two different battery cell types with significantly different internal impedances. Having a higher internal impedance in the cell is undesirable, as it results in higher internal losses, resulting in increased internal temperatures. The internal impedance of a battery cell is a good indicator of its aging. As we’re pushing the battery cells to the limit in our use case, we’re pretty interested in how the battery cell characteristics change over time, going through heavy use. To simulate heavy use of the battery cells, we’re using three Itech IT-M3432 power supplies in parallel. The IT-M3432 is a bidirectional DC power supply capable of delivering up to 800W, 60V, and 30A. Running three of them in parallel allows us to charge and discharge battery cells at up to 90A, enabling us to test the different candidate battery cells thoroughly. We can subject the battery cells we’re testing to realistic load cases in a

controlled environment with this equipment. Using the IT9000 software, the supplies are programmed to emulate different competition events, using current consumption data collected from previous seasons. This way, we’re able to verify whether or not the cells have enough capacity, in addition to ensuring that it will be safe to operate the battery cell with these load conditions. Besides testing individual battery cells, we’ve also done testing with a fully assembled accumulator using the Itech IT6012C-800-40. This power supply is mainly used for doing inverter & motor testing at our motor testbench. Since it is a regenerative power supply, it can both source and sink current, making it a good fit for testing the battery accumulator. The power supply can be adjusted up to 800 VDC, source or sink up to 40 Amperes, and deliver/sink up to 12 kW. Using the IT-6000 series supply, we’ve been able to test the thermal performance of our battery accumulator in a controlled environment. This has given us valuable information about our cooling solution for the battery accumulator and enabled us to test different cooling concepts in the real world quickly, not just using computational fluid dynamics. 4Test Instruments has been an essential partner in testing individual batteries and the battery accumulator, having donated and loaned out the equipment 29

mentioned above to Revolve NTNU. With this equipment, we’ve acquired valuable information about the different battery cells we’ve tested, which will be helpful in a future battery pack redesign, in addition to leading to improvements in the battery cooling solution for our upcoming vehicle.

Trondheim Stål is a Norwegian company founded in 1989, specialized in steel products towards the construction industry. They are one of the few partners which have been with us from the very start. As a result, they have contributed with parts to every single racecar Revolve NTNU has built. Trondheim Stål is located 20 min south of Trondheim at Hofstad næringspark Melhus with over 50 skilled employees, including engineers and machine operators. They are certified for the standards: NS-EN 1090-2, EXC 3, ISO 9001 and ISO 14001. Their production methods consist of welding, bending, laser cutting and water cutting. Even though, Trondheim Stål is a specialist of steel production they help us with machining of more advanced material for racecars: cutting of precise carbon fibre inserts from thick carbon fibre plates, used for mounting parts to the monocoque, cutting of aluminium

honeycomb, which is laminated in the monocoque and form the structural part, cutting of copper for the bussbars of our high current circuit boards. In addition, they produce many parts for us in aluminium and steel. Trondheim Stål is a trustworthy partner who is easy to communicate with. They deliver parts on time, and on a short notice if needed, always in high quality. Trondheim Stål is our partner which individually produce the most unique parts and number of parts in total.

Asbjørn Ringes Verlo 31

Chief Mechanical Engineer

Photo: Mia Elisenberg (Revolve NTNU)

A RE YOU RE A FOR OUR NEW CAR?

A DY W

Drivers Herman Fjellestad Aerodynamics

Mia Elisenberg Marketing

Endre Stedje

Power Systems

Jostein Brovold

Embedded Electronics

Asbjørn Verlo

Chief Mechanical Engineer

33 Photo: Trond He (Revolve NTNU)

AURORA

SPECS Total weight: 162 kg CG height: 241,26 mm without a driver Downforce: 1053 N @ 60 km/h

AERODYNAMICS • 1053 N of simulated downforce at 60 km/h, 10% increase • Total aerodynamic package weight of 8.6kg • 1400 design iterations & 1.5 million CPU hours

ELECTRONICS • Sensor system with wireless capabilities • Fully 3D-modelled wire harness • Integrated autonomous system support in Vehicle Control Unit • 32-channel LiDAR • Lightweight, rugged and high-performance Processing Unit

AUTONOMOUS SYSTEMS • Self-developed coupled Economic Model Predictive Control utillizes a dynamic model of vehicle dynamics to pro-actively decide actuator inputs • RTK system combined with a GNSS base station improves state estimation accuracy and reliability • Longitudinal control minimizes latency and runs the algorithm at a rate 8 times higher than last year 36

CHASSIS • Total weight: 19.9 kg • Simulated torsional stiffness of 3570 Nm/ degree roll • Integrated heave-roll damper system

SUSPENSION & POWERTRAIN • New damper configuration • Topology optimized uprights • Improved sun gear coupling • 1557 Nm torque

SOFTWARE • Direct yaw-moment control based Torque Vectoring running at 400 Hz • In-house developed software with a comprehensive toolbox for vehicle analysis and support for real-time parameter tuning

DRIVER INTERFACE • Redesigned ergonomic package where the seat is casted to the median driver size • 15 Nm of autonomous steering torque • Autonomous braking system integrated into master cylinder with pneumatic actuation • Redesigned steering system: bevel gear box designed to fully integrate the actuator for steering 37

K. Lerøy is a specialized manufacturer, supplying precision made components in tough materials for all kinds of customers. They are involved in a wide variety of industries, and are an important partner to make a new car every year. This is K.Lerøy’s fifth year with us, and this year, as previous years, they are helping us machine parts for the gearbox, more specific the carrier, pretention nut and they deliver the inspection lid. We are very happy and amazed of the consistency in quality and finish.

Uvdal Maskinfabrikk (UMF) has made the complex bellcranks for the new damper system on the new car, and Revolve NTNU are wery happy with the bellcranks. Uvdal Maskinfabrikk offers production of mechanical parts, assembled products and precision components in advanced materials. Their production facility consists of precision machines of the highest quality. For more than 40 years, UMF have developed into a solid and reliable supplier, offering complex mechanical production of high quality products. They possess solid technical competence and engineering capacity for prototype production and total projects. Revolve NTNU considers UMF to be a practical and effective company that state-of-the-art parts.

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POWE R SYST EM S Elias Helle Kalland

Group Leader Power Systems

There is no secret that the students in Revolve NTNU have made fast and great race cars for many years. Since our first electric vehicle in 2014, Revolve NTNU has been developing our tractive system up until our 2021 car Luna. This has resulted in in-house developed inverter and accumulator. To compete at the highest level in Formula Student, one thing is to have a fast car, but the main factor that separates the cliff from the wheat is a reliable car that is able to always maintain race pace during competition. The Power Systems group is tasked with delivering reliable high voltage power to our four motors. With the help from Embedded Electronics’ battery management system and inverter, we deliver up to 80 kW which gives the car an acceleration from 0-100 km/h in around 2,3 seconds! The group is also responsible for the wiring harness, cooling system and making a brand new motor test bench. As mentioned previously, to win in Formula Student, reliability is key. As such, the goal this year is to make our car more reliable and the main focus for the group has been to improve reliability over new designs. The wiring harness is a system that contributes a lot to the reliability of the car. Bad contacts and crimps and cables exceeding bending radius all add up to down time in the electrical system. To counterfeit this, the group has worked hard with planning the wiring harness in CAD throughout the year. This means that we design the wiring harness on a computer, with correct cable, wire and connector data. After we’ve iterated through all the possible ways the cables can go, and found the best solution, we make a flattened route in 1:1 scale. This is a powerful way of manufacturing the wiring harness, as it allows us to terminate cables way before the monocoque is even made. We know the exact cable length we need, as well as what connector we crimp. This saves us

time, and will also let us debug contacts and crimps without sitting in an awkward position inside the monocoque… So far, the year has brought all kinds of challenges and ups and downs for both group members and for me as a group leader. The group consists of 3 electrical and 3 mechanical positions, with systems that apply mechanics, electricity, materials science, fluid dynamics and production methods of both mechanical and electrical parts. Keeping track of all the systems as a student in mechanical engineering is a challenging task! In an engineering organization, it’s natural that you will learn a lot about engineering and working on interdisciplinary projects. Having a thorough technical knowledge to challenge the members in their designs is important, but I’ve spent more time facilitating for the members to get all the resources and info they need to work at their best. This includes having an overview of what our group needs to do for the organization and what we need from the organization. What this means is that I’ve learned a lot more in handling personal relationships and human interactions, than “engineering” itself. This is a valuable experience that I don’t think I would learn anywhere at NTNU other than in a technical organization. I can go on for a long time explaining all the positives of being a part of Revolve NTNU and Power Systems, but in short, getting the chance to lead an interdisciplinary group with members not only from all over Norway, but the whole world, is an experience that I’m forever grateful to have. The group consists of highly intellectual and wonderful people, and working with them day in and day out is something I truly appreciate.

The goal of having the wiring harness in CAD is to be able to terminate cables before the monocoque is finished. Example photo of a flattened route drawing.

As responsible for the cooling, simulations of the air flow through the accumulator casing is key to make sure systems operate in optimal conditions. The picture shows the temperature of our battery segments in the accumulator casing.

RE A D M O RE A B O U T B EING A P OW ER SYS T EM S MEMBER 41

Caleb W. Sy

Accumulator Cad

TheAccumulator Casing People often associate Formula Student race cars with flashy aerodynamics, a sleek monocoque, and powerful electric motors; but just as essential to a race car is its battery pack. Without stored energy, the car cannot run at all, much less go fast. To supply this energy, we use 288 battery cells with 6550 mAh of capacity. With so many cells and so much stored energy, it is important that we keep the cells safe inside a protective enclosure, and also to keep the drivers and our crew safe in case of a fire caused by our batteries. This is where I come in. My job in Revolve NTNU is to design and produce the casing of the battery pack, which we call the accumulator. The casing is made of kevlar and carbon fiber composite panels which we produce in house. We use these materials because they provide excellent strength-toweight ratios and they are also fire retardant certified. Having this position has exposed me to so many different experiences. I have learned how to use CAD software, use a CNC machine to mill MDF for moulds, produce machine drawings of parts that I have designed, and many more. These are things that I have heard about in lectures, but never had any practical experience in - but now I do. We truly embody our motto, “Theory in practice”. Beyond my personal development as an engineer, I have come to regard Revolve NTNU as a place to nurture personal relationships as well. During the first days of being in Revolve NTNU, I was worried that I would not fit in. Oh, how the whole team quickly proved me wrong! Despite being an international student and not knowing any Norwegian, I felt included and supported by my fellow Revolvers. I learned that language and culture is truly not an obstacle, only our passion for motorsport and competition matters in the end. I truly regard the team as my personal friends, and I could not have asked for anything better.

Maria Schubring Cooling System

The Cooling System I joined Revolve NTNU as a technical member as a part of the Power Systems Team. In my position as the cooling responsible I designed the cooling system for the R22 car. My bachelor in Mechanical Engineering, which I completed in a university in Germany, was organized in a theoretical way. This barely gave me the chance to get an insight into the actual task of an Engineer. As a Result, I arrived in Norway with the craving of practical application; in that sense the ambition: “From a student to an engineer in one year” - sounded exactly like what I was looking for. In Revolve NTNU I got the chance to learn how to 3D-model, process fluid dynamics simulations and execute adequate calculations to dimension a complete technical system, all in less than a year. Everyday I get confronted with a task I never had to face before:

How to physically produce a Nylon 3D-Printed part ? • How to adequately maintain a sponsor interaction ? • How to precisely plan validation testing of the accumulator cooling ? ;which enables you to never stop progressing. •

On top of that, I am bonding with a team of 70 dedicated young engineers from a variety of technical fields, as well as students from other majors, which gives me the opportunity to widen my knowledge and as a result further shape the imagination of the engineer I want to be.

43 Photo: Trond He (Revolve NTNU)

SEMCON & REVO LV E N TN U, A PERFECT M ATCH ! With a dedicated focus on innovation, our office in Kongsberg is known for its creative culture and exciting, innovative technical solutions, always with the end user in focus. Semcon is an international product development company with more than 1800 employees around the world. We combine technology, usability and design in new ways – from creative concepts to production systems and digital information solutions.

Revolve NTNU is a front-runner when it comes to new technology, this is important for us to support. Semcon Norway strives to be the best in innovation, focusing on new products, systems and services. Just like Revolve NTNU, we must be in front of the technological development to provide our customers the best service, and together create new business opportunities.

Semcon’s office in Norway is located in Kongsberg with about 85 employees. We work with development of complex systems and solutions within a wide range of industries. Our projects varies from electrically adjustable skibindings for Rottefella, new technology for cancer treatment, to an advanced remotely operated robotic vehicle for more sustainable shipping. We deliver complete systems, with the ability to start from an idea and go all the way to a finished product. Most of our projects are executed in-house, with a multi-disciplinary team mainly within the fields of mechanical-, softwareand electronic- engineering; which contributes to our creative and open culture. We look at the Revolve NTNU project with great interest, knowing that the team consist of next generation upand-coming engineering stars.

“In order for us to be able to offer our customers the expertise they require, it is important that we keep up-to-date on the latest technology and research. The development is rapid and we must continuously improve to stay ahead and be relevant.” - Hans Peter Havdal, Division Manager Semcon.

Our prototype-workshop, which is a central piece of our iterative development process, has delivered high quality components to Revolve for many years. A few of the deliveries has also been manufactured on very short notice on request from the project, this reflects our agile approach to the projects we run.

T HIS YEAR, S E MCO N H AS PRO D U CE D OU R S EVERA L O F O U R MOTO R PART S, INCLUDING T H E ROTO R, H O U S I NG A ND ENDBELL, AS W E LL AS TH E R E A R UPRIGHTS! 45 Photo: Trond He (Revolve NTNU)

Mjøs Metallvarefabrikk AS is a manufacturing company, with in-house production capabilities for prototyping, casting, machining, assembly, and testing. Our key strategy is to support our customers with production knowhow and provide engineering services with a real design-for-production approach. We are a company that is well equipped for engineering turn-key solutions; as a stand-alone service or in joint cooperation with the customer. Mjøs Metallvarefabrikk AS manufactures a

wide variety of mechanical precision components for the maritime industry, the offshore and subsea market, as well as other demanding industries. Our facility is located on Osterøy, just north of Bergen. Mjøs Metallvarefabrikk AS was established in 1865, hence representing more than 150 years of proud heritage within the foundry and machining business.

Technology Mjøs Metallvarefabrikk AS focuses on state-of-the-art technological solutions to ensure competitive and sustainable production of mechanical components and products. This requires sustained focus, continuous development of our own organization, and the technological tools and equipment we utilize in production. To ensure our competitive strategy, we are conducting a number of internal development projects, and are participating in extensive development

programs with renowned industry partners and research institutions. We strive to maintain a close dialogue with relevant educational institutions, both to ensure the recruitment of future employees, and to convey the industry’s requirements and expectations of the respective educational institutions. We look at sponsoring Revolve NTNU as a great opportunity to support technological development, and to participate in the creation of an ever more impressive race car. The journey taken on by a new team of students each

year, truly correlates to our own mission - putting theory in practice. Since we started working with Revolve NTNU in 2018, we’ve almost made it a tradition to machine their rim centers. During the 2020 season we also took upon us the challenge to machine their new aluminium uprights, and for the 2021 season we machined their new rim centers , which also functions as the hub for their gearbox. This season we’re machining an iterated version of last year’s rim center, which will make space for the brake system.

“Mjøs Metallvarefabrikk AS helps us machine complex three dimensional structures, which enables us to push the performance of our car. We appreciate the machining expertise they bring to the project and hope to continue the cooperation” - Marius Dørmenen, Gearbox and motor.

47 Photo: Trond He (Revolve NTNU)

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