Traction control of a Formula Student prototype

09/27/2021

Controlling tire slip is crucial for race cars performance, such as Formula Student prototypes. With four independent wheel-hub electric motors, the future prototype from FST Lisboa - with both driverless and person-driven configurations - provides an opportunity to directly control the state of the four tires and improve dynamic performance. A traction control system must handle nonlinearities and be robust to parametric changes or uncertainties to improve dynamic vehicle behaviour. To fulfil these requirements, a cascade control architecture based on proportional control and tire dynamics is proposed, being able to simultaneously fulfil longitudinal and lateral dynamics requirements. A feedback component is employed to track the longitudinal speed and fulfil tire and electric motor constraints, while a feedforward term is used to track the yaw rate and achieve torque vectoring in turns. Both components improve the vehicle ability to accelerate, decelerate and turn, mitigating the natural tendency to break traction in vertically unloaded tires due to mass transfers. A power distribution module corrects the individual torque commands to enforce electrical power limits in acceleration and deceleration. A heuristic method is suggested to tune the traction control parameters. The sensitivity of the resulting traction controllers is studied for varying traction conditions and vehicle parameters, assessing the proposed solution's robustness. Finally, the traction controllers are validated on generic race tracks, with a higher degree of complexity from the benchmarks used for tuning.

Authors in the community:

• 

  A

  André Filipe Alves Grancho Barroso

  ist176063

Supervisors of this institution:

• 

  J

  José Raul Carreira Azinheira

  ist12745

• 

  A

  Alexandra Moutinho

  ist13959

mechanical-engineering - Mechanical engineering

por - Portuguese

Instituto Superior Técnico