Inverse Kinematics Analysis for a Mobile Manipulator with Redundant DOFs

Abstract

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 1st, 4th and 5th 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 2nd and 3rd 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.