Vehicle speed dependent assistant control for electric power steering systems

摘要

This paper considers vehicle speed dependent assistant control problems for electric power steering systems (EPSs). According to the requirement analysis of the vehicle speed dependent assistant control, a mathematical model of EPSs is established, and a double closed-loop control system structure is proposed. Based on the assist characteristic of the desired steering wheel torque, the function model of desired steering wheel torque on vehicle speed is designed. Theory analyses show the double closed-loop control system structure can make the output torque applied to the steering wheel at different vehicle speeds are always close to the desired steering wheel torque, and tracking control without steady error for the EPS is realized. The EPS simulation model is established by using Simulink, and the PI control strategy of the torque controller is used to simulate the EPS. Simulation results show the control system structure and the vehicle speed dependent assistant control strategy are easy to implement, and the control effect is better.