Relay-based friction identification in frequency domain

This paper addresses the application of a dual relay feedback approach towards the identification of frictional effects in servo-mechanisms. The friction model consists of Coulomb (including possibly directional Coulomb or load bias) and viscous friction components, both of which can be automatically extracted from suitably designed relay experiments. At the same time, the dynamical model of the servo-mechanical system can be obtained from the experiments. These models will be directly useful in the design of the feedback controller and the friction compensator. Results from a simulation study are presented to illustrate the practical appeal of the proposed method.