Formula Student application of Xsens MTi-G-710 sensor, by UPC ecoRacing
Formula Student is the most important international engineering competition between universities from around the globe. Each year, hundreds of teams take part of the numerous events held in Australia, Asia, America and, mainly, in Europe. This competition follows strict rules which ensure the safe and fair rivalry between teams, resulting in cars designed to be very responsive and agile due to the nature of the tracks. This fact, combined with the prohibition of professional drivers, make driving aids a key factor.
Nowadays, the ultimate innovation in this field in Formula Student electric vehicles is the incorporation of Torque Vectoring, which enables the control of all four tires thanks to the incorporation of four in-wheel motors and a well-designed set of sensors to monitor car’s behaviour.
Assessing tire performance
Tires are widely considered as the most important part of a race car, as they are the only connection with the racing track. The entire car is designed around them, and various systems are implemented to make them work at their optimal performance as often as possible. Two key parameters of tires are the slip angle and the slip ratio. The first is responsible for grip, stability and control when the car is going around a corner, whereas the later accounts for acceleration and brake performance of the vehicle. Finding the optimal slip angle/ratio at every situation to obtain the desired amounts of stability and control is what Torque Vectoring is about. In order to obtain both slip parameters, monitoring of crucial car parameters such as motors rpm, wheel torque and car’s speed is accomplished with the help of sensors like Xsens’ MTi-G-710, among others, as well as other parameters such as the yaw rate, used to estimate the stability of the vehicle.
The role of the Xsens MTi-G-710 sensor
Electronics are then used to adjust the required current needed by each motor at all times to help the driver steer in the corners with greater stability and to ensure good traction during acceleration. The Xsens MTi-G-710 sensor is a more accessible solution to be able to monitor car’s absolute velocity respect to the ground through its GPS technology, compared to a slip angle sensor. In addition, the Xsens MTi-G-710 sensor is used as a tool to assess driver’s abilities and key performance indicators (KPI), as Xsens MTi-G-710 is capable of measuring lateral and angular accelerations, enabling the debriefing of car’s performance on the track.
The sensor was incorporated to the ecoRX, the latest UPC ecoRacing electric single- seater and the first Spanish car incorporating 4 in wheel motors. The car has also fully selfdeveloped electronics, and the experience adquired with the Xsens MTi-G-710 sensor and all the gathered data will help the students in learning about vehicle dynamics and improving their future prototypes in the following seasons.
For more information:
Xsens MTi-G-710 Sensor: https://www.xsens.com/products/mti-g-710/