Title

Optimal control for electrical power-assisted steering system.

Date of Award

2005

Degree Type

Thesis

Degree Name

M.A.Sc.

Department

Electrical and Computer Engineering

Keywords

Engineering, Automotive.

Rights

CC BY-NC-ND 4.0

Abstract

An electric power-assisted steering (EPS) system has been gradually used to replace hydraulic power steering (HPS) in recent years. In an EPS system, an electric motor generates assisting steering torque to make comfortable steering operation for drivers. To achieve better driving feeling in the EPS system, there are three problems need to be addressed: Sufficient assist torque should be transferred to drivers; road roughness and road reaction torque shall be taken by the controller; system transient response shall be accelerated by the controller. Various control algorithms have been derived now, however, most of them are derived simply based on the motor model [1],[6] and given this design strategy, they are not able to handle and consider the full system specifications very well. In this thesis, a new controller structure design is proposed for an EPS system that addresses disturbance attenuation, offering sufficient gain and achieve system transient response at the same time. We introduced a new two control strategy to design the controller that incorporates a motion controller and a motor torque controller in different loops. The motion controller is an optimal H2 controller which takes care of the disturbance attenuation and accelerate system transient response issues. The motor controller is a P-I controller that is used to generate sufficient assistant torque according to the command input from the motion controller. The simulation for the whole EPS system is implemented by CarSim and simulink. CarSim will simulate the road reaction torque and the EPS model is built on the simulink platform. All the results are not only tested under the off-line simulations, but also transformed to a real-time format and verified through real-time simulations. In both cases, it fulfills the control objectives and achieves good performance.Dept. of Electrical and Computer Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2005 .C445. Source: Masters Abstracts International, Volume: 44-03, page: 1426. Thesis (M.A.Sc.)--University of Windsor (Canada), 2005.