A passivity-based motion control of redundant manipulators using weighted decomposition of joint space

In this paper, a passivity-based motion tracking controller for kinematically redundant manipulator is proposed. Based on the weighted inner product in joint space, a minimal parametrization of the null-space can be achieved. Combining this minimal set of null-motion with kinematic relation, we obtain new extended task space formulation. Employing the inertia matrix as a metric, an inertially decoupled dynamics between the task space and null-space can be obtained and a trajectory tracking control law is proposed based on the passivity. The performance of the proposed controller is verified through experiments with a planar three-link direct-drive manipulator.