Multi-objective weighted isotropy measures for the morphological design optimization of kinematically redundant manipulators

The morphological design of kinematically redundant robotic manipulators is a non-trivial, task-specific process. The availability of redundant degrees of freedom (DOF) affords a redundant manipulator an infinite number of motion solutions for a given task, thereby allowing the achievement secondary manipulation goals. Motion control methods play an integral role in the quality of redundancy resolution, but the degree of resolution attainable by these methods is ultimately determined by morphological design. In this study, a weighted isotropy measure is developed for use in optimizing kinematically redundant manipulator design quality. This measure is designed to quantify manipulator performance on multiple secondary motion goals. The measure is employed as a morphological fitness metric for a constrained non-linear morphology optimization problem. Optimization results show that using the weighted isotropy measure significantly increased the performance levels of a kinematically redundant manipulator, with respect to secondary manipulation goals, for the intended set of tasks.