Multi-objective geometric optimization of a multi-link robot manipulator considering dynamics performance.

With the increasing emphasis on both quality and efficiency of automatic production, the motion stability and accuracy of a robot manipulator under heavy loads are becoming more and more important. It becomes imperative to optimize the dynamic performance of a robot manipulator for heavy-loads tasks, that is to improve the design of the mechanism and to optimize the mechanical properties of the whole system. In this study, we analyzed the dynamic model of a serial manipulator used for replacing disc-cutters in Tunnel Boring Machines and established an iterative algorithm to calculate the actuation torque for each joint during dynamic tasks. The dynamic manipulability index and the torque optimization index were proposed to evaluate the actuation requirement for the whole system. Then, a multi-objective optimization framework was established considering both kinematics and dynamics performance of the manipulator. The optimization was implemented using NSGA-II algorithm and we evaluate the optimize result from length compactness index and length balance index. The torque of the solution after optimization is obviously reduced and meet the performance index. The proposed optimization method can help improve operational precision and efficiency in constrained space.