Dealing with the time-varying parameter problem of robot manipulators performing path tracking tasks

The path tracking problem of a robot manipulator with time-varying parameters is considered. Using the properties of the element-by-element product of matrices, the robot dynamics is obtained in parameter-isolated form, from which a new control scheme is developed. The stability is addressed by verifying an integral inequality motivated by the Barbalat lemma, rather than the more common Lyapunov method. The proposed controller yields zero asymptotic tracking errors when applied to robotic systems with time-varying parameters by using a switching-type control law. It is shown that the controller presented does not involve much online computation since it only depends on bounds on the variation of the system parameters, which can easily be predetermined offline