Link Lengths Optimization Based on Multiple Performance Indexes of Anthropomorphic Manipulators

How to determine the optimal link length parameters according to task requirements and constraints is a key problem in the design of anthropomorphic manipulators. Considering multiple performance indexes such as dexterity and end stiffness, this article presents a method on how to maximally improve the comprehensive motion performance of anthropomorphic manipulators by optimizing the link lengths. Firstly, the joint motion ranges of human arm are obtained through analyzing the motion mechanism and the motion forms. Then the kinematics model of manipulators with the optimal configuration is established by using screw theory, and a comprehensive evaluation index for the motion performance is proposed by considering the Jacobian matrix condition number, manipulability, and end stiffness. Taking the evaluation index as the objective function, the corresponding constraints and the optimization model are established to optimize the link lengths of manipulators with both flexibility and stiffness. Through comparative analyses, it can be seen that the global comprehensive performance index value of the optimized anthropomorphic manipulators increases by about 23.97%, and the motion performance is significantly improved.