newsletter October 2018
LiDAR Testing at Dragvoll Text: Anna Hermansen Photos: Martin Sandberg & Morgan Heggeland
Last year’s driverless car, Eld, came second at FSEast and is generally considered to have a stable and competitive autonomous system. This means that Team 2019 have the difficult challenge of improving something that already works. Our Perception & Navigation (P&N) group has looked at different ways to improve their part of the autonomous system, such as improving detection of the cones that mark up the track. A better detection system includes spotting cones further away and correctly identifying as many cones as possible, while filtering out anything that is not a cone. If they manage this the autonomous system will be able to drive at higher speeds and still stay on track. So how do you improve last year’s detection system consisting of a Velodyne VLP-16 LiDAR, that already works fairly well? A fool’s answer could be to get another LiDAR. So that is exactly what we did. Now, the next
step is figuring out where to place our two LiDARs. Our Detection Specialists want to find the optimal placement of the LiDARs on the car. As every decision in Revolve must be based on empirical research, the solution was to test it. Luckily, we have the backing of one of Norway’s largest universities which has plenty of space available, so P&N went up to Campus Dragvoll and started testing! The testing itself was fairly simple: P&N mounted last year’s LiDAR in front of different setups of cones at three different heights. Theese correspond to possible mounting positions on this year’s driverless car, Atmos, and sensor data was recorded. They also conducted some tests with the LiDAR on a moving trolley to simulate the movement of the car. With this test data the team will be able to place the LiDARs in a way that makes the detection more accurate and with longer range, and in this way making the autonomous car faster and better.
The Power of CAD & CAE Text: Martin Berger Illustrations: Ole Martin Gjerde & Kristoffer Weaver
To design a racecar, one needs models. Here at Revolve NTNU everybody use Solidworks as our Computer Aided Design (CAD) software. Because there are different people working on different parts of the racecar we all use the same program. This ensures that we are consistent during the design phase and that we in the end have a functioning model of the entire racecar.
It is quite easy to recreate something to 99% in CAD. But 100% is really hard. There are multiple good reasons for why you would want to model your parts. The most obvious is for use in production. For machining or 3D-printing of the parts a model can be fed to a machine which then uses the model to create a physical part. This can be done through milling a mould or machining out the part itself. The aerodynamics package and the monocoque are both made by using a mould. Another good example is our uprights. They have been 3D-printed by la-
ser sintering of titanium powder. Another very important use of the models is in Computer Aided Engineering (CAE). This is done by giving the models additional parameters like weight and material type. With these parameters we can simulate important properties of the parts, like their strength or the weight distribution of the racecar. The model can also be put into a simulation program like Star CCM which takes the model and simulates fluid flow around the part (e.g. air). Changing parameters makes us able to choose the best design which meet the requirements we set and optimize things like weight and strength of the parts. During October, CAD has been a priority. Having models to run tests on and to see how the systems work together is the first major step towards a new racecar.
New Test Rigs Text: Øyvind Storvik Ingebrigtsen Illustrations: Kristoffer Haugland
The big problem with simulations is the baseline fact that they exist in a completely virtual world. Therefore, basing your entire design on simulations can have disastrous consequences. Luckily for Revolve NTNU, Kristoffer Haugland has a solution to this problem. He is currently building a testing jig that can confirm simulations on the drivetrain. This is Kristoffer’s second year in Revolve NTNU and last years experience from working on engine design can come in handy when working on his new job dimensioning in the Suspension & Drivetrain group. Kristoffer is currently studying mechanical engineering at NTNU and is in his 5th year. Kristoffer made most of the design of the jig himself, but has also used Revolve NTNU’s internal experience with all things engineering related. The final design promotes a simple solution that can apply forces in the X-, Y- and Z plane. By first applying forces in the Z plane or lifting the wheel up with a normal carjack, then applying force on a moveable place, you can apply forces directly to the cars suspension and drivetrain. This is then picked up by the cars internal sensors. All of the data is then collected and used in calculations. If these values are the same as in the simulations, you know you are on the right path. All of the countless hours used on simulators, design and testing is to answer the suspiciously simple question; How much weight is too much weight? Every extra gram can add stiffness, but will also slow the car down. Maybe shaving two grams off the suspension is enough to win? A good example of this is Revolve NTNU’s second place in the Skidpad event last summer. We came 0.001 seconds behind first place. Every single gram counts when it comes to racing! The goal with the test rig is to create a good framework which future teams can use to correctly dimension their suspension.
Going Go-carting Text & Photos: Ă˜yvind Storvik Ingebrigtsen
As a varied diet is important for a healthy stomach, a varied day is important for a healthy head. Building a racecar is amazing. You get to challenge yourself every single day and see yourself progress in the art of engineering, project management and communications. But sometimes it is just fun to do something else. Therefore, Revolve NTNU went go-carting this month! This also included our previous drivers. That meant the challenge this years team faced this time was to get as close as possible to the drivers. One of our drivers named Roberts RaÄ?ko who earlier has been the eastern European champion in go-carting had the most obvious leg up in this competition and he really showed the real competence and finesse that goes into motorsports at that level. Even though most of the team had no chance of winning, doing new and difficult things together is a great teambuilding exercise! The team is going to spend the better part of next year working in close proximity with a limited budget, little time and more challenges than we can imagine. Having a strong team is crucial for our success. Having a strong team means more than just having a smart team. It means to have a team that can meet challenges together and come out on top. A team that does not falter and keeps working together to make everyone better. A team like our team here at Revolve NTNU! It is also a great way of picking new potential drivers from the team. Since we build a racecar we also need somebody who can drive it.
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