Robust identification of nonlinear frictional dynamics for advanced controller design

The robust identification of nonlinear frictional dynamics constitutes a significant challenge for the model based friction compensation in advanced control of electro-mechanical drives. This paper discusses the frictional phenomena in pre-sliding and gross sliding regime described by the advanced General-Maxwell-Slip friction model and proposes a robust identification approach to determine their distributed parameters. The nonlinear dynamics of a drive chain with multiple frictional surfaces is described. The appropriate control signals are designed to excite the friction dynamics in both pre-sliding and sliding regimes. The estimation of friction parameters relies on the recursive least square (RLS) technique with a suitable set of regressors. The identified model is compared with experimental data and applied in a tunable framework for the model based friction compensation.