Redundancy decomposition control for multi-joint manipulator

Abstract

A control method called redundancy decomposition control is proposed for the resolved acceleration control of a manipulator equipped with redundant degrees of freedom. In this method, the redundant degrees of freedom of a given manipulator are decomposed into nonredundant subsets. For every time interval from t to t +Δ t, the acceleration of the corresponding subset of degrees of freedom is assumed to be controlled and the inverse kinematics and dynamics as well as the evaluation function are calculated using the nonredundant inverse Jacobian matrix. The calculation is performed in parallel for all the combinations of degrees of freedom. The optimum set of degrees of freedom is selected and it is used for the control of the time interval t to t+Δ t. The proposed method is reviewed in comparison with conventional approaches, including the pseudoinverse matrix and null-space vector techniques. It is demonstrated that the proposed method almost always realizes better motion planning than the other two techniques, and is effective in real-time control.