Fault-tolerant control scheme based on reference adjustments for a 4WD electric vehicle with actuator faults and constraints

A fault-tolerant control (FTC) scheme for the path tracking of an electric vehicle (EV), which has four electromechanical wheel systems, is proposed. With wheel slip constraints and certain faults, a passive fault-tolerant controller based on the low-high gain control is developed to maintain the system´s stability and guarantee an acceptable performance. If the performance degrades under a given threshold, an active fault diagnosis (AFD) approach is used to isolate and to evaluate the fault more precisely. A reference adjustment technique (RAT) with the designed controller are used to guarantee the safe implementation of AFD. As soon as the diagnosis information is available, an accommodated controller is reconstructed to recover the degraded performance as best as possible. Finally, simulations of traction engine faults for a 4WD EV are conducted to illustrate the proposed scheme.