Formula Student: the crucial role of the IMU/GNSS

The Formula Student is an international educational engineering competition in which teams of students from around the world design, build, and race their own formula race cars. The competition includes 3 categories: Electric, Driverless, and Combustible cars.

Formula Student participants must not only build the fastest race car but also excel in endurance, acceleration, and skid pad performance.

As an expert in Inertial Navigation Systems and partner of several teams, we interviewed various teams of engineers using our Inertial Measurement Unit (IMU) combined with Global Navigation Satellite System (GNSS) to understand what the key elements to success are.

The Importance of the IMU/GNSS for Precise Car Dynamics

The IMU/GNSS provides decisive information on the car state such as position, speed, yaw rate, slip angle, acceleration and orientation to the competing teams’ cars, as stated by D. Kiesewalter, from AMZ Racing: “We required an IMU for several reasons. Primarily to determine the position state of our car.

We also needed to have efficient dynamics control & a reliable and accurate determination of Euler Angles (roll, pitch, and heading).” This way, engineers of electric and combustible cars can understand what to improve by comparing the actual state to the theoretical one.

Formula Student car dynamics criteria

Mastering acceleration is primordial during Formula races. When the car accelerates too much, it can drift, which causes the wheels to wear out. To minimize tire wear and get the most of the engine’s power and performance, acceleration has to be checked.

Tracking the race car trajectory is essential. A circuit analysis is conducted thanks to the IMU/GNSS data, especially position, and helps determine if the car is well positioned inside the circuit or when turning.

Let’s not forget that the Formula Student is a race. One of the competition goals is to go faster on the track than the other teams. Speed is therefore a crucial factor to study, thanks to the IMU/GNSS. But it is even more important for electric race cars, as they need to track the consumed energy.

Driverless race cars: Taking the best of Heading and Navigation out of the IMU/GNSS

Racing cars may use single-antenna GPS for heading, but driverless vehicles rely on dual-antenna IMU/GNSS for precise heading. It allows faster initialization and delivers true heading even in stationary position.

J. Liberal Huarte from UPC Driverless (ETSEIB) explains that heading and localization are essential for other parts of the equipment to function properly: “When we operate with LiDAR technologies, the fact that you are headed 1 degree to one side or the other influences a lot the position.

So, precise heading is a big requirement. And also, localization and mapping: it is very important to localize yourself in the X, Y.” Therefore, implementing a Dual GNSS/IMU in this type of race car is the best solution, as it provides true heading and position, which also helps stabilize the LiDAR.

Heading is as important as precise navigation for driverless race cars. Real Time Kinematic (RTK) allows an extremely accurate estimation of the position (1-2 cm). The more accurate the IMU/GNSS is, the more the car is able to stay in the circuit lane without drifting.

The IMU/GNSS analyzes the circuit to ensure optimal car positioning and trajectory optimization.