Design of Reconfigurable Steering Feel for Steer-by-Wire System Based on Dynamic Load Observation

Since the steer-by-wire (SBW) system removes the mechanical linkages of the steering wheel and front tires, the reconstruction of steering feel becomes a significant research topic. In this paper, a hybrid framework to achieve the reconfigurable steering feel is designed, which is composed of alignment torque, assisting torque, damping torque, and limit torque. The modeling of alignment torque is based on the dynamic load observation. An extended disturbance observer (EDO) is designed to realize the real-time estimation of rack force, and provide a real-time feedback of the dynamic loads from the tire-road interaction. Moreover, a friction torque assisting model is proposed to further optimize the smoothness of steering feel. And damping compensation is used to enhance the return performance. To validate the effectiveness of proposed method and evaluate the performance of dynamic load observation, a hardware-in-the-loop experimental platform is built. Objective evaluation method is adopted to evaluate the performance of the designed steering feel. The influence of steering parameters is analyzed by the evaluation indicators of different steering experiments. The experimental results indicate that the proposed model can be tuned to have the reconfigurable steering characteristics of vehicles.