The Control System For In-wheel Driven Electric Vehicle

A comprehensive study of the key techniques of the control system for in-wheel driven Electric Vehicles (EV) is conducted in this dissertation.Firstly, a sliding mode based optimizer is introduced. The proposed optimizer requires neither a prior knowledge of the surface type nor the relationship between the coefficients of the adhesion and the wheel slips since the objective function is related only to the vehicle velocity, leading an improvement in both adaptive and real-time adjusting abilities. Therefore, its identification results of the optimal sliding rate for different road surface conditions are more promising.Secondly, a novel optimal slip based antilock braking system (ABS) is proposed. The braking system includes mainly a sliding mode based wheel slip optimizer, a sliding mode based nonlinear observer, and a sliding mode based ABS controller. The function of the sliding mode based wheel slip optimizer is to maintain the optimization wheel slip, that of the sliding mode based nonlinear observer to estimate the vehicle velocity from the output of the system, and that of the sliding mode based ABS controller to regulate the wheel slip to reach its optimal value. The salient advantages of the proposed braking system are (1) its robustness, (2) its excellent ability to response the wheel slip, and (3) its high time-efficiency for decelerations.Also, based on the combination of the computational intelligence and the sliding mode control, an ABS and a traction control (TC) systems are, respectively, developed. This low-cost but high performance controller can guarantee that the to-be controlled system can response exactly the ideal moving trace, avoid the drawback of the control chattering occurred in the classical sliding mode control, and therefore improves significantly the robustness of the systems.Thirdly, a novel electric differential algorithm is independently developed. Compared with the traditional mechanism differential ones, the turning performance and the controllability of the response of the proposed algorithm are enhanced. Based on an efficient and low cost design methodology, a simplified electric differential strategy for low speed EVs is also developed. To validate the proposed work, the electric differential control system based on TMS320F2407 DSP is implemented on a prototype vehicle, and the experimental results demonstrate its feasibility in engineering applications. In addition, a communication system based on CAN and RS232 buses for In-wheel motor driven EV is built to realize the real time monitoring and fault diagnosing of the runningstates of a vehicle.In the appendix of this dissertation, the details about a new designed 2-phase Permanent Magnet Brushless in-wheel Motor are summarized. Also, the performance comparisons of computer simulation and tested results are given to demonstrate their good agreements.