Student Team Delft -The DUT23-

Formula Student Team Delft setting acceleration world record driven by Eurocircuits’ PCBs

Throughout the past year, we at Formula Student Team Delft have been working hard to develop a new Formula Student contender with the goal to win at the competitions we would attend. With a team of 90 eager students, we worked on all disciplines of engineering and design. from chassis, suspension, aerodynamics and drivetrain to powertrain, software and of course PCB design, where Eurocircuits supported us with their fast production. All coming together in order to create our best racing car yet, the DUT23.

Formula Student is an international engineering competition that challenges university teams to conceive, design, build, and race a single-seat formula-style race car. The competition involves two main areas: static and dynamic events. Static events include Design, Business Presentation, Cost Analysis, showcasing engineering, planning and financial skills. Dynamic events consisting of Skid Pad, Acceleration, Autocross, and Endurance test the car’s performance in speed, handling, and durability. These events are intended to create well-rounded engineers with both theoretical knowledge and practical skills for their later career.

Season marked by highs and lows

This season was far from smooth sailing, fate would strike two weeks before we presented our car at the rollout. After moving the accumulator, it sadly went up in flames right next to the car. Fortunately, no one was hurt, and secondary damage was minimal, however this still posed a big setback for the team. In the end, we managed to refurbish last year’s accu to accommodate this year’s rules and get our car driving. This, however, together with difficulties with CNC production and our motors, meant that the car wasn’t finished nearly as far as we would have liked it to be at our first competition: Formula Student Netherlands. At FSN we passed all technical inspections and drove at all dynamic events despite the weather. In the end we had to settle for 7th place out of the 33 teams participating. But of course, we were determined to improve for the next competitions.

FSEast in Hungary

In the 2 weeks leading up to the next competition, we worked hard to finish the car. We successfully completed the implementation of four-wheel drive, started some careful first meters of our autonomous system. We also installed our front wing and got some much-needed testing time in. After arriving at FSEast we fitted our big aero elements, the side diffusers, just in time for the technical inspection. After finishing all inspections, we went straight to acceleration. Here the car must accelerate from standstill to cross the 75m line as fast as possible. On our first attempt we drove a respectable 3.49 seconds. However, with the new setup, it was determined that our car had significantly more grip than we initially thought. So, for our second attempt, we updated our launch and traction control to provide more force. This turned out to beperfect as with our tires now driven in and the car pushing to its full potential, we managed to set a time of 2.999s passing the finish line with a speed of 122.45 km/h. With this, we set the fastest time ever recorded on formula student competitions to date. To put this in perspective, the fastest times before this was a 3,209s by Green Team Stuttgart at FSEast 2021.

Technical issues

After this initial success, unfortunately, we faced some technical issues ending our Autocross run prematurely. Furthermore, during endurance, a single wire failed, breaking the ‘Ready-To-Drive’ sound. A sound the competition rules require the car to make when entering ready-to-drive mode. Which meant we weren’t allowed to drive the second half. This cost us a lot of points for the dynamic events. On the statics side, we improved a lot compared to FSN and placed second on the statics events. For the engineering design event we almost scored full marks presenting our Eurocircuits PCBs.

Final competition

In the week between FSEast and our final competition in Germany we stayed with our fellow formula student team KA-RaceIng at Karlsruhe. There we got time to improve and test our car. At FSG we managed to finish our first autonomous discipline ever at a competition. Placing 4th at autonomous acceleration with a 5,08s time was a great achievement. Last year we didn’t manage to implement the autonomous systems. We only had a few days of high-speed autonomous testing before the competition took place. With this feat we have laid the groundwork for years to come with the autonomous future of Formula Student.

Not everything went seamlessly though, as with the autonomous skidpad our car went of course, hitting the timing equipment. This meant that we had to fix the frontwing. This unfortunately wasn’t the only thing we had to fix.  The next day our suspension failed on the test track after it got too hot in the sun. This meant we couldn’t take part in the Acceleration event and the suspension glue broke again during the Endurance event. We did, however, score highly at the static events placing 2nd overall again and receiving the 1st place for Cost and Manufacturing.

©FSG Wintermantel.

©FSG Wintermantel.

PCB development this year

Lots of electronics go into making a race car drive and almost all the PCBs we design and produce ourselves. Eurocircuits supported us in this endeavor by producing all the bare PCB boards. In our first Blogpost of this year we already dove into the Accumulator Management System. This is a set of PCBs which monitor and control the accumulator. One of the systems best showcasing our design and Eurocircuits capabilities is our self-developed motor controller.

Motor controllers

The motor controllers, also called inverters, take the up to 600v DC power from the Accumulator and generate the 3 phase outputs driving the motors of the car. The development started after 2017 and although we first drove with them in 2021. We keep on improving the design. It consists of 3 parts: a high current PCB housing the switching MOSFETs and decoupling capacitors where we use Eurocircuits’ thick copper buildup capabilities. A second pcb placed right on top of this houses the gate drivers driving the MOSFETs and sensing circuitry for measuring voltage and temperature. The third and final PCB contains all the processing, communication and current sensing. This year we managed to further reduce the total height of the full assembly by another centimeter. Our 2019 Eurocircuits blog  also dove into our motor controller design and the test setup back then and the difference in high and simplicity of the motor controller is striking. To achieve this, we integrated a separated control card and optimized the layout to reduce the PCB size by 40%. For this we used Eurocircuits high density Class 8D technology to still stay within the affordable poolable category while being able to properly fan out the high density BGA chip. Eurocircuits has a blog post on designing with BGAs for manufacturability and cost where the best practices for designing with BGAs is explained which was of great use.

Final words

Through the highs and lows, setbacks and triumphs, we’ve honed our skills, built connections, set a new limit of what’s possible in Formula Student. Although we missed our mark of placing first overall, we still put-up incredible results and gained invaluable experience. Eurocircuits helped our team of students grow, learn and improve ourselves. The PCB engineers attained firsthand experience designing, producing, testing and improving their designs.  The software team learned about board bring up, testing and writing efficient embedded software for custom hardware.

Now that the year is over a new team has come together to pick up the torch and develop our next year’s generation, the DUT24.

I am looking forward to where they will take this team and don’t doubt that we’ll hear more from them in the future. AHOO!