Development of a control algorithm for a tie-rod-actuating steer-by-wire system

Abstract

This paper presents a control algorithm for a steer-by-wire (SBW) system. In an SBW system in a passenger car, the usual mechanical linkage between the steering wheel and the front wheels is replaced with an electrical connection. An SBW system consists of two parts: the steering-wheel system and the front-wheel system. This research considers the tie-rod-actuating type of front-wheel system, in which two independently actuating motors control the front wheels. The steering-wheel and front-wheel motors are modelled, using the bond graph method for both, but controlled by different means. The steering-wheel system control algorithm used a torque map to generate reactive torque and damping. In the development of the tie-rod-actuating-type SBW system described herein, the Ackerman constraint was used for control of the two motors to improve stability and manoeuvrability. The validity of the system was verified with a full-car model.