Study of Yaw Moment Control Strategy of Four Wheel IndependentDrive Electric Vehicle

A yaw moment control strategy for four wheel independent drive electrics vehicle is proposed in this paper. The control strategy is a hierarchical architecture which containing a yaw motion generation layer and a longitudinal force distribution layer. The yaw motion generation layer consists of feedforward control and feedback control. Unlike previous strategy, in this paper, yaw rate is considered as the only control variable which is feasible to be detected in practice. The feedforward control is used to enhance overshoot in transient condition while the feedback control is to change vehicle steady state steering characteristic and extend its lateral limit. The longitudinal force distribution layer is designed based on vehicle wheel load transfer model. It makes each tire fully utilized its lateral force limits. Based on these two layers, a control model is built accordingly. Both steady state and transient state experiments are conducted in Carsim simulation associated with the built Simulink control model. The simulation results show that proposed control strategy can enhance vehicle handling performance in steady state and transient state. Experiments were conducted on an electric vehicle which evaluated the accuracy of the established model and the effect of the proposed yaw moment control strategy.