Abstract The passive fault-tolerant approach for four-wheel independently driven and steered (4WID/4WIS) electric vehicles has been investigated in this study. An adaptive control based passive fault-tolerant controller is designed to improve vehicle safety, performance and maneuverability when an actuator fault happens. The proposed fault tolerant control method consists of the following three parts: 1) a fault detection and diagnosis (FDD) module that monitors vehicle driving condition, detects and diagnoses actuator failures with the inequality constraints; 2) a motion controller that computes the generalized forces/moments to track the desired vehicle motion using Model Predictive Control (MPC); 3) a reconfigurable control allocator that redistributes the generalized forces/moments to four wheels with equality constrained optimization. The FTC approach is based on the reconfigurable control allocation which reallocates the generalized forces/moments among healthy actuators once the actuator failures is detected. If one or more in-wheel motors lose efficacy, the FDD module diagnoses the actuator failures first. Then the reconfigurable control allocator accommodates faulty in-wheel motors and reconfigures the control allocation law of the healthy motors to achieve the desired vehicle motion to the greatest extent. Numerical simulations have been conducted to verify the proposed algorithm. It has been shown that the FTC controller prevents the fault further expands, and displays the effectiveness of the proposed fault tolerant control approaches in various driving scenarios. Introduction Four-wheel independently driven and steered (4WID/4WIS) electric vehicles is a promising vehicle architecture due to its potentials in emissions and fuel consumption reductions. 4WID/4WIS electric vehicles utilize four in-wheel motors to drive the wheels independently and four steering motors to steer the wheels independently. However, owing to the significantly increased system complexity and numbers of actuator, the probability for actuators fault taking place is higher. It is thus necessary to design control systems which are capable of detecting, identifying, and tolerating potential actuator faults, so as to improve the reliability and safety for the 4WID/4WIS electric vehicles. Among the existing fault-tolerant control for 4WID/4WIS electric vehicles, several approaches have been proposed. For instance, Zhang [1] [ 2] put forward an active fault tolerant control method based on model-following and command input management techniques. Wang [3] proposed an active fault tolerant control approach based on the estimated control gain of the faulty in-wheel motor in order to allocate the control efforts among other healthy wheels automatically. Maki [4] considered a strategy for fault tolerant control system using multiple controllers based on robust control techniques. However, the foresaid fault-tolerant control method exist two drawbacks. First of all, they are just aimed at 4WID electric vehicles, namely the influence of the steering system failure is not taken into consideration. In addition, the fault diagnosis strategies which focus on hardware redundancy (HR) and analytical redundancy (AR) use a huge amount of redundant sensors and algebraic computation. In view of above-mentioned issue, we propose a fault tolerant control (FTC) approach which is composed of fault detection and diagnosis (FDD) module, motion controller and reconfigurable control allocator. Fault diagnosis module locates the fault of the actuators which is composed of in-wheel motor controller, current sensor and in-wheel motor and decides to corresponding fault styles by means of actuator signals analysis. Motion controller is designed to determining the generalized forces/moments to track the desired vehicle dynamics, and most of the control methods for motion controller are around model following control [ 5], nonlinear co