Fault tolerant control scheme based on active fault diagnosis for the path tracking control of a 4WD electric vehicle

This paper investigates the path tracking problem for an electric vehicle which has four electromechanical wheel systems under normal and faulty conditions. A fault-tolerant control scheme is proposed with considering the input saturation and certain actuator faults. From initial period, a passive fault-tolerant control is applied to achieve the tracking objective. When a fault happens, if some performances degrade below an acceptable level, an active fault diagnosis algorithm is implemented to precisely localize the faulty wheel and to estimate its fault gain. During this period, the reference input adjustment technique and the designed passive fault-tolerant controller will guarantee the active fault diagnosis implementation. With the faults information, an accommodated controller is designed to recover the degraded performance caused by the faults. Finally, simulations of traction engine faults in a RobuCar™ vehicle are conducted to illustrate the proposed method.