Fault-tolerant driving control of a steer-by-wire system for six-wheel-driving-six-wheel-steering vehicles

This paper describes a fault-tolerant driving control strategy for steer-by-wire system failures in six-wheel-driving-six-wheel-steering vehicles. The fault-tolerant driving control algorithm was designed to obtain vehicle manoeuvrability as close as possible to that of non-faulty vehicles by redistributing the tractive forces of the non-faulty wheels. Since a faulty steer-by-wire system induces a high lateral tyre force, which is the resistance to the yaw motion of the vehicle, a high-wheel slip control strategy is used to minimize the resistive lateral tyre force of the faulty steer-by-wire system. The fault-tolerant driving performance of a faulty six-wheel-driving-six-wheel-steering vehicle was investigated via computer simulations. To investigate the effectiveness of the proposed fault-tolerant driving control algorithm, the fault recovery rate was defined and calculated in terms of the vehicle manoeuvrability. Simulation studies show that the proposed fault-tolerant driving control algorithm can significantly improve the vehicle manoeuvrability, compared with the optimal traction redistribution method.