Study on optimal slip ratio identification and traction control for electric vehicle

The key technologies of Traction Control System (TCS) are the identification of the optimal slip ratio and the control of the optimal drive wheel slip ratio. This paper applies a Two-stage estimator, which integrates the recursive least-square algorithm with forgetting factor and the PI estimator, to estimate the real-time road adhesion coefficient. Then, the fuzzy analysis is applied for classification of the current road conditions and calculation of the optimal slip ratio for current road condition. A PID controller is used to control the electric motor torque to keep the real-time slip ratio of the drive wheels around the optimum slip ratio. Finally, the vehicle test verifies the identification and the control of the drive wheel slip ratio effective.