Research on Variable Steering Ratio Control Strategy of Steer-by-wire Steering System
Due to the elimination of the mechanical connection, the steer-by-wire steering system can freely design the angular transmission ratio between the hand steering wheel and the road steering wheel. In this paper, the variable steering ratio control strategies under normal driving conditions and unconventional driving conditions were proposed. The variable steering ratio control of normal driving conditions is based on the ideal yaw rate gain, taking into account the low-speed steering lightness and high-speed steering stability, and the steering ratio varies with the vehicle speed and the hand steering wheel angle, which ensures the vehicle steering sensitivity at low speed and the steering stability at high speed. The variable steering ratio control of the unconventional driving conditions is based on yaw rate dynamic feedback control, and the steering ratio varies with the vehicle movement status.