Inverse Kinematics Analysis for a Mobile Manipulator with Redundant DOFs

A mobile manipulator is a manipulator mounted on a mobile robot. This paper proposed an inverse kinematics analysis method for a mobile manipulator with redundant degrees of freedom (DOFs). The DOFs of the end-effecter are assigned properly among the mobile robot´s 3 DOFs and the manipulator´s 5 DOFs: the rotation freedoms of the mobile robot and the manipulator´s 1^st, 4^th and 5^th joint contribute to the orientation of the end-effector; while the two translation freedoms of the mobile robot and the rotation freedoms of the manipulator´s 2^nd and 3^rd joint contribute to the position of the end-effecter. Based on this DOFs assignment method, two restrictions are introduced for inverse kinematics calculation without changing the work space of the end-effector. Experiment results are included to demonstrate the performance of the results obtained by this inverse kinematics analysis. In these experiments, based on the information of the target´s position and orientation obtained from an on-board CCD camera, the mobile manipulator is controlled to catch the target by utilizing the inverse kinematics analysis strategy proposed in this paper.