Multi-mode control method based on fuzzy selector in the four wheel steering control system

To solve the problem that an alone control method can't suit to every running condition of the four-wheel-steering (4WS) vehicle, a multi-mode control strategy was suggested based on fuzzy selector that can get perfect control effect for the four-wheel-steering vehicle. The strategy could be used to achieve the optimal yawing angular velocity, centroid edge angle and bodywork heeling angle by controlling the steering angles of the front and rear wheels. The analysis of the steering behaviors under the different working condition was carried out by fuzzy selector to choose the appropriate control mode and determine the corresponding control arithmetic to improve the vehicle's steering characteristics under various working conditions. The numerical simulation was carried out with the selector which combined the proportional control and the self-adaptation control as an example. The results indicate that the multi-mode control strategy can meet the requirements of the four wheel steering under the different working conditions and has better control efficiency than a single mode control strategy.