Optimal Controller Design for Electric Power Steering System Based on LQG

Because of the complex factors of the road random excitation, the torque sensor measurement noises and the interference caused by model errors in the electric power steering system(EPS), EPS controller must provide substantial robustness. In this paper, the mathematical model of EPS was established and the state-space expression with random interference signal was constructed, a control design method was introduced which employed the boost curve to form a feedforward control and LQG feedback to ensure refined performance, robustness, and disturbance attenuation. The controller was tested via simulation and the simulation result shows that this proposed controller can effectively attenuate the external interference and improve the system robustness.