A robust and optimal LQR controller design for Electric Power Steering system

This paper presents a Linear Quadratic Regulator (LQR) employed to improve performance of an Electric Power Steering (EPS) system. Generally, EPS is a full electric system having an electric motor which provides the assist torque on the steering mechanism in order to reduce the workload and to enhance the steering feel of the driver during steering process. Three main technical areas are described in this paper. First, the principle and structure of EPS are presented including the dynamic model. Second, LQR technique is employed to derive an optimal controller for the EPS system. Finally, the combined tools of Matlab/Simulink and dSPACE provide the environment for modeling the controller in software and applying it to the actual hardware via a digital signal processing board based on the DS1401 Micro Auto Box. Comparison and analysis between the simulation results and dSPACE hardware results are discussed.