Analytical inverse kinematic solution for modularized 7-DoF redundant manipulators with offsets at shoulder and wrist

The objective of this paper is to develop an analytical inverse kinematic solution for a 7-DoF redundant manipulator with offsets at shoulder and wrist. Firstly, the key ingredient is to derive closed-form inverse kinematic solution using different joint as redundancy based on parameterization method. By having these redundant parameters,we obtain different null-space self-motion pattern of the arm. We then can select a proper redundant joint. The method is consistent with calculating augmented Jacobian matrix. Lastly, the derived equations are verified with a modularized 7-DoF manipulator with offsets at shoulder and wrist, which consists of modularized components designed and built by our laboratory.