Design of Anti-Disturbance H∞ Controller of Automotive Electric Power Steering System

Abstract

Automotive EPS controller is easy to be affected by the parameter perturbations, road agitations, sensor noises and the lateral wind disturbance in the process of vehicle operation. These uncertainties affect the accuracy of assist current, the EPS performance and the driving safety. The mathematical model of EPS system was established including the internal uncertainty and external disturbance. The LFT linear fractional transform representing model and M matrix with stripped uncertainty were designed. The robust H∞ controller and weight function were designed according to the H∞ control theory and performance indexes of EPS system. The comparative performance with PD controller was made. The results showed that the H∞ controller had better robustness and robust stability than the PD controller. It also had great anti-disturbance performance to satisfy the performance requirements of EPS system.