An Examination of the Maneuverability of an All Wheel Steer Vehicle at Low Speed

With the goal of improving the driver's steering performance, the four(all) wheel steering(4WS) system was designed, and theoretical and experimental analysis of the 4WS system was investigated. In the 4WS system the low speed maneuverability is better due to a smaller turning radius. In reality, however, the opposite steering of the rear wheels could be counter-productive for certain maneuvers as shown in the Fig.1. In this paper, this counter-productivity is called the parking problem.

The objective of this study is to prevent the parking problem and to maintain the maneuverability of the 4WS vehicle. To accomplish this goal, a new concept of the 4WS system for the low speed range has been introduced. It is proposed that the rear wheel steering angles should be zero for any front wheel steering angles at zero velocity and after the vehicle is started the real wheels should be steered to maintain their original direction for a moment before the rear wheel steering angle reaches the limit of the rear wheel steering angle.

Under this new concept, the 4WS system vehicle was investigated. The results show that the new 4WS system reduces the parking problem and maintains the maneuverability of the vehicle.