Adaptive Regulation of Manipulators Using Only Position Measurements

This article considers the motion-control problem for uncertain robot manipulators in the case where only joint-position mea surements are available, and proposes an adaptive controller as a solution to this problem. The proposed control strategy is general and computationally effrcient, requires very little infor mation regarding the manipulator model or the payload, and ensures that the position-regulation error possesses desirable convergence properties: semiglobal asymptotic convergence if no external disturbances are present, and semiglobal con vergence to an arbitrarily small neighborhood of zero in the presence of bounded disturbances. It is shown that the adaptive controller can be modified to provide accurate trajectory track ing control through the introduction of feedforrvard elements in the control law. The adaptive regulation and tracking schemes have been implemented in laboratory experiments with an IMI Zebra Zero manipulator. These experiments demonstrate that accurate and robust motion control can be achieved by using the proposed approach.