Automatic Friction Identification and Compensation with a Self-Adapting Dual Relay

The application of a dual relay feedback approach towards the identification of frictional effects in servo-mechanisms will be presented in this paper. The friction model, thus identified, will consist 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, from the same experiments, the dynamical model of the servomechanical 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 simulation and experiments are presented to illustrate the practical appeal of the proposed method.