Date of Award


Degree Type



Electrical and Computer Engineering

First Advisor

Dong, Lili

Subject Headings

Automobiles -- Steering-gear, Automobile driving -- Steering


In this thesis an Active Disturbance Rejection Controller (ADRC) is applied to Electrical Power Assist Steering (EPAS) system which assists the driver in steering the steering wheel of an automobile. Our control objective is to reduce the steering torque exerted by a driver, so that good steering feel of the driver will be achieved in the presence of external disturbances and system uncertainties which are very common in the EPAS system. The robustness and stability of ADRC controlled EPAS system is investigated through frequency-domain analyses. The Bode diagrams and stability margins demonstrate that the control system is stable during the operation and it is robust against external disturbances and structural uncertainties. In addition, the ADRC is simulated on a column-type EPAS system. The simulation results show that using the proposed ADRC, the driver can turn the steering wheel with the desired steering torque, which is independent of load torques that tend to vary with the change of driving conditions