A Robust Adaptive Friction Control Scheme of Robot Manipulators

In this paper, the tracking problem for robot manipulators in the presence of unknown friction and modeling uncertainties is considered. A composite tracking control scheme is proposed in which an adaptive friction estimation is used to estimate the extent of friction and a robust controller is then designed to enhance the overall stability and robustness. It is shown that the design of the friction estimator and that of the robust control gain can be conducted separately. Performance issues of the robust adaptive friction controller are illustrated in a simulation example made for a two degree of freedom planar robot manipulator.