Application of CAN in vehicle traction control system

In this paper, CAN bus, which works in good real-time and high reliability, was designed and applied to meet the need of real-time control for traction control system (TCS) of 2WD vehicle. TCS controllers were developed which include two electrical control units (ECU): one is the host ECU which receives the signals from sensors such as the wheel speed sensors, longitudinal acceleration sensor, accelerator pedal position sensor, and engine throttle position sensor, and sends the control commands to the actuators according to the control algorithm. The other is the throttle controller which receives the throttle control command from host ECU by CAN bus to run the engine throttle actuator by which engine output torque can be reduced to avoid the excessive spin of the driving wheels. Meanwhile throttle controller feedbacks the running states of the actuator to the host ECU by CAN bus. In addition, the host ECU controls the hydraulic control unit (HCU) to regulate brake torque of driving wheels to control wheel slip. To verify the reliability of TCS controllers and the accuracy of data transmission over CAN bus, the hardware-in-the-loop (HIL) tests were performed by means of the vehicle rapid development system (RDS). Test results show that not only CAN communication is reliable and accurate, but also TCS controllers can effectively keep the slip rate of the driving wheels in the optimum range and improve the driving ability of the vehicle.