Dynamic characteristics of multi-function four-wheel steering system 2000-05-0245

Turning at high speed, doing sharp turning at low speed, and doing parking are three critical motions of a vehicle needed to be considered. This research studied dynamic characteristics of a multi-function four-wheel steering system that could improve directional stability of vehicles on turning at high speed, minimize radius of turning of vehicles while doing sharp turning at low speed, and reduce spaces needed on parking motion.

Four methods were used to study dynamics characteristics of a multi-function four-wheel steering system. Those four methods were method of constant yaw rate, method of equal side slip angle, method of zero side slip, and method of negative side slip or controlling side slip angle.

The results of the study show that the method of zero side slip is the best method to determine rear wheel angle needed for a vehicle doing parking motion in order to minimize radius of turn. When a vehicle is turning at high or medium speed, rear wheel angle needed should be determined by method of negative side slip angle.

A multi-function, four-wheel steering system could improve directional stability, sharp turning performance, and parking performance of a vehicle.