Introduction of the high performance area measure for the evaluation of metamorphic manipulator anatomies

The modular metamorphic manipulator has been proposed in previous work as a concept of a robotic manipulator, where a single structure could be metamorphosed offline to different anatomies. In this paper, a global kinematic measure for the evaluation of the emerging anatomies, of a given structure of a class of 3 d.o.f. modular metamorphic manipulators is introduced. The proposed high performance area (HPA) measure depicts the dexterous workspace defined by a chosen threshold of a local kinematic index to meet the specifications of the given task. The region of the anatomy's workspace, where the selected local kinematic index meets the specifications is cross-sectioned by the XZ-plane in C-space, and the maximum area formed is the HPA. In order to reduce the computational burden, a procedure is proposed to approximate the HPA. The HPA is used to formulate an optimization problem for the determination of the optimal anatomy of a given metamorphic structure, which is solved using a genetic algorithm. A case study application of a 3 d.o.f. metamorphic structure is presented, using the manipulability measure and the conditioning index as local indices. The presented results are thoroughly discussed and the paper concludes with some hints for future work.