On-Line Identification of Viscous Friction in Electric Power Steering

Evaluation experiment by using random steering operation

Abstract

The steering feel of electric power steering might deteriorate by the change of viscous friction with the secular change or the temperature change. For this reason, we consider that it is possible to improve the steering feel if the viscous friction can be identified online during driving and the controller gains can be retuned on the basis of the identified value of the viscous friction. In this paper, we propose an on-line identification method of viscous friction and verify the effectiveness by using random steering operation to the EPS test bench.