The control strategy research of the electric power steering system considering the influence of the road adhesion coefficient

In this paper the EPS model and Steering-torque model of the steering pinion were built, and the road adhesion coefficient was estimated by the relationship among the tire slip angle, the tire lateral force and the road adhesion coefficient. Then the control strategy of EPS when in steering or aligning process was proposed, which can be realized by reducing the assistance motor current and using the sliding mode control. Finally, the vehicle test has performed to verified the effectiveness of the control strategy, the results of which indict that it is a good performance of the control strategy.