Handling Improvement for Distributed Drive Electric Bus Based on Torque Vectoring Control Method

Abstract:

Based on the distributed electric drive system， a handling improvement method was designed for a distributed drive electric coach using torque vectoring control. In view of the large load transfer， the strong coupling characteristics of tire， the suspension， and the steering system during coach corning， the relationship among equivalent lateral force， aligning torque， and the tire sideslip angle were described respectively by using polynomials. A mass estimation algorithm was designed to modify the lateral stiffness when the vertical load of the wheel changed. The vehicle reference steering characteristics was defined considering vehicle nonlinear characteristics， and the feedforward term of torque vectoring control at different steering angles and speeds was designed. In order to improve the robustness of the controller， an anti-integral saturation sliding mode variable structure control law was used as the feedback item of the torque vectoring control. The simulation and experiment results show that by using the proposed controller the vehicle steering characteristic is closer to neutral steering， and the mean value of peak steering angle in slalom test is reduced by more than 21%， which means the handling performance is significantly improved.

Key words:distributed drive electric bus;torque vectoring control;direct yaw moment control;handling performance