Application of switched-dynamics friction models in feedback control

Abstract

In the last decades, several friction models suitable for control purposes have been proposed, which are able to represent most of the observed friction behavior. However, this comes at the cost of an increased complexity, presenting in some cases switched dynamics, as in the generalized Maxwell-slip friction model. Thus, consideration of these models in control design certainly increases the complexity of stability proofs, and thus, their use in control design except for feedforward compensation. The purpose of this work is to provide stability results to facilitate the application of these models in feedback control. First, results are given for a more general model with switched dynamics, and then results are given for the particular case of the generalized Maxwell-slip model. Then, the application of these developments is illustrated for the case of a deterministic robust control design for a linear motor drive. In this case, controllers with feedforward and feedback friction compensation are implemented in an experimental setup, showing the improvement in performance that can be achieved using the latter.