Traction Control of a Three-Wheeled Electric Motorcycle

Sammanfattning: Traction control is a widely used control system to increase stability and safety of four-wheeled vehicles. The company OMotion AB develops and builds threewheeled electric vehicles. With a new model in development they want to increase the safety. This thesis presents the work of developing and implementing a Traction Control System (TCS) for that new model. Previously, a thesis work had been done at OMotion that implemented a slip control system for the longitudinal dynamics [Karlin, 2021]. It detected slip of the rear wheel and limited the torque to regain grip. However, the controller does not handle lateral slip. When cornering and pushing the throttle too hard the rear wheel can lose grip and oversteer, potentially resulting in a serious accident. By measuring the speed of the vehicle and the steering wheel angle, a desired yaw rate is obtained. This is compared to the actual yaw rate of the vehicle, giving a yaw-rate error which the feedback controller acts on. To investigate the behavior of the vehicle with different control strategies, a model was built in Matlab’s Simulink. The model can simulate longitudinal and lateral dynamics together with the forces on the tires. The tire model used was the Dugoff tire model. The simulation performed well and made it possible to test different control strategies before implementation and testing on the real vehicle. Tests showed that a less aggressive controller was needed due to the disturbances that a real non-ideal driving surface brings. After the controller was properly tuned, the TCS successfully prevents a driver from losing control when accelerating too aggressively in a corner.