On the robust tracking control of kinematically constrained robot manipulators

This paper addresses the problem of robust controller design for holonomic constrained robotic systems which guarantees global asymptotic and exponential like stability of joints´ position and velocity tracking error. It is well known that the presence of the constraints makes the controller design more complex as compared to the unconstrained robots such as serial manipulators. Control algorithms should be developed to satisfy both the system dynamics as well as kinematic constraints without explicit computation of the inverse kinematics. The paper develops a new robust control algorithm which can be applied in trajectory tracking control for both parallel and constrained serial manipulators. The method considers the constraint forces in the system dynamics to improve the system stability and tracking performance. The controller is designed through the direct Lyapunov approach and ensures asymptotic and exponential like stability in the position and velocity tracking errors. In order to verify the validity of the proposed control algorithm the algorithm is applied on two different illustrative examples.