MIXED ROBUST/ADAPTIVE CONTROL OF ROBOT MANIPULATORS BASED ON A CLASS OF SATURATION FUNCTIONS

This paper proposes a class of mixed robust/addaptive control schemes without linear PD feedback for trajectory tracking of robots with uncertainties. The control structure consists of a adaptive controller used to compensate for the parametric uncertainty and a nonlinear robust controller used to compensate for the unparametric uncertainty. The main feature of the control approach is that a new class of nonlinear sliding variables and continuous nonlinear robust controllers are developed based on a class of saturation-type functions to simplify the controller design. It is shown by Lyapunov's theorem and simulations that uncertain effects such as frictions and external disturbances are e lim inated, and also the global asymptotic stability can be warranted.