Study On Acceleration Slip Regulation Control Strategy Of Four-wheel Independent Drive Electric Vehicle Based On Road Identification

With the advatanges of in-wheel motors’ s torque can be controlled indenpentedly and can be measured easily, four-wheel independent drive electric vehicle becomes an important research direction of electric vehicle. However, the wheel slip often occurs if a four-wheel independent drive electric vehicle works on a low adhesion road, which may lead to vehicle instability even vehicle rollover. As a result, the driver’s safety must be threatened. In order to solve the problem, an acceleration slip regulation control stategy based on road identification is proposed, aim to improve the vehicle stability as well as safety. The main work is as follows:1. This paper had a research on vehicle structure and stability of four-wheel independent drive electric vehicle. Moreover, the main functions of driving system and control system are analyzed, and the requirement of vehicle stability control are studied.2. The mathmatical model and vehicle velocity control strategy of four-wheel independent drive electric vehicle is studied. Seven degree of freedom vehicle model, the magic formula tire model are studied. In addition, this paper designed vehicle velocity control strategy of four-wheel independent drive electric vehicle, and verified this vehicle velocity based on Carsim and Matlab/Simulink.3. An acceleration slip regulation control stategy based on road identification is presented. Considering that the optimal slip ratio vary with road condition, a road identification algotithm is designed to estimate the optimal slip ratio of wheel in real-time. Then, in order to solve the problem that the wheel slip often occurs if a four-wheel independent drive electric vehicle works on a low adhesion road, an acceleration slip regulation control stategy based on road identification is presented, which can make full use of the road adhension coefficient and improve the vehicle stability and safety.In this paper, low adhension road condition, opposite road condition and split road condition is selected in simulation, and vehicle velocity control stategy and an acceleration slip regulation control stategy based on road identification are built respectively in these road condition. The results of simulation shows that the acceleration slip regulation control stategy based on road identification can improve vehicle stability and safety and the control performance of the acceleration slip regulation control stategy is better than the control performance of vehicle velocity control stategy.