Model independent friction compensation

It is shown that our earlier (1997) robust adaptive nonlinear controller for friction compensation achieves a robust performance for a general class of models capturing friction dynamics. The advocated control design methodology can be used with many existing dynamic models of friction and is robust to parametric and dynamic variations in these friction models. Furthermore, the properties of a generalized dynamic friction model are set-forth and these generic properties are exploited for control design purposes. It is also shown that many of the popular dynamic models fall within the class of models considered. The advocated controller guarantees global asymptotic tracking of the states of a one degree-of-freedom system in the presence of dynamic friction effects. Simulation studies are done for three popular dynamic friction models and a stochastic version of one of the dynamic friction models. These simulations sufficiently elucidate the robustness and performance aspects of the advocated control design methodology