Adaptive Fault-tolerant Tracking Control of 4WS4WD Road Vehicles: A Fully Model-independent Solution

This paper investigates the path tracking control problem of four-wheel-steering and four-wheel-driving (4WS4WD) road vehicles. Of particular interest is the development of an adaptive and fault-tolerant tracking control scheme capable of compensating vehicle uncertain dynamics/disturbances as well as actuation failures simultaneously. Control algorithms are derived without requiring detail system dynamic information. The control scheme is shown to be effective in coping with unexpected actuation faults without the need for analytically estimating the bound on actuator failure variables or other uncertainties. The proposed method is validated and demonstrated through its application to a wheeled vehicle with four steering wheels and four driving wheels, where high precision path tracking is achieved in the face of steering faults.