New robust-Adaptive Algorithm for Tracking Control of robot manipulators

Based on a continuous piecewise-differentiable increasing function (CPDIF), a new simple robust-adaptive tracking control algorithm is proposed in this paper for robot manipulators. In the structure of the proposed adaptive controller, output of the estimator is filtered by some CPDIF and then is employed in the controller. Therefore, in some sense, this robust-adaptive approach can be taken as the extension of the conventional adaptive scheme. Due to this bounded filter function, phenomena of parameter drift are overcome accordingly. When the true parameters are contained within the estimated parameter range, asymptotic stability is obtained even though persistency of excitation is not satisfied. Furthermore, the designed controller renders the resulting system uniformly ultimately bounded stable in the presence of disturbance and/or the improper estimate of parameter range especially, namely, robustness is also guaranteed. Finally, simulation results demonstrate the above statements.