Active steering control strategy of steer-by-wire system based on variable steering ratio

Active steering control strategy in steer-by-wire system was studied based on variable steering ratio. The influence of steering ratio on steering sensitivity and the desired yaw rate gain was analyzed through simulation, to improve the controllability and stability of steer-by-wire system. Set the minimum closed-loop deviation of vehicle controllability and stability as the goal, the desired yaw rate gain was optimized using genetic algorithm, and the surface chart of variable steering ratio was desired based on different vehicle speed and steering wheel angle. Under steering wheel angle step input test procedure and steady static circular test procedure, the results show that variable steering ratio can improve vehicle steering sensitivity at low-speed and improve steering stability at high-speed, which can reduce driver burden and ensure driving safety.