Adaptive Robust Control of Robot Manipulators: Theory and Comparative Experiments

Adaptive robust control schemes are developed for the trajectory tracking control of robot manipulators. The schemes utilize a dynamic sliding mode and achieve a guaranteed transient performance and nal tracking accuracy in the presence of both parametric uncertainties and uncertain nonlinearities. In the absence of uncertain nonlinearities, the schemes also achieve asymptotic tracking. In addition, three conceptually di erent adaptive and robust control schemes | a very simple nonlinear PID type robust control, a gain-based nonlinear PID type adaptive control, and a combined parameter and gain based adaptive robust control | are derived for comparison. All algorithms, as well as two benchmark adaptive schemes, are implemented and compared on a two-link direct-drive robot. Comparative experimental results show the importance of using both proper controller structure and parameter adaptation in designing high performance controllers. It is observed that in these experiments, the proposed scheme improves tracking performance without increasing control e ort.