Design and implementation of robust adaptive controller for direct drive manipulators

In this paper, we consider a dynamics of actuator driving system as well as actuator itself to design a robust adaptive controller for robot manipulators. We propose an adaptation law to guarantee the boundedness of parameter estimates irrespective of the boundedness of other closed-loop signals without data normalization. We also propose a control law to ensure the uniform stability of the closed-loop system without a priori knowledge of the unmodeled dynamics. We show that the tracking error belongs to the normalized error bound, and also show the robustness of the proposed adaptive controller by using an experiment referred to a two-link direct drive manipulator