CHARACTERISTICS OF THE FOUR-WHEEL STEERING VEHICLE AND ITS FUTURE PROSPECTS

The present paper deals with some features of four–wheel steering vehicle, compared with the existing front–wheel steering vehicle. First, we calculated the basic characteristics after four–wheel steering vehicle, which can steer the rear wheels relative to the front–wheel steering angle. From this calculation we found that in this new type of vehicle we could deal separately with the yaw velocity and lateral acceleration characteristics appearing in response to steering angle input. Then the control capability of the new steering system was examined through closed–loop tests on an experimental four–wheel steering vehicle actually operated by subjects in a follow–up control manner at a proving ground. The findings indicate that the four–wheel steering system helps a great deal in improving vehicle controllability and stability. In other words, it may give a driver–vehicle system much better control capabilities. We believe that further research efforts should be made to establish active control technology for the four–wheel steering vehicle as one of the future chassis technologies that promise to advance greatly the dynamic performance of motor vehicles.