Kinematics optimization of a novel 7-DOF redundant manipulator

Abstract

Redundant manipulators can accomplish complex tasks due to the redundant degree of freedom (DOF). At the same time, their kinematics calculations are complicated. In this study, the kinematics solution for a self-designed 7-DOF redundant anthropomorphic manipulator is obtained, and an optimization method is provided to optimize the motion time of the manipulator in the same trajectory. Kinematics analysis of the spherical parallel shoulder joint was performed by using a geometric method and coordinate transformation. Kinematics analysis of the redundant manipulator was performed by a geometric method with an optimizing arm angle. Linearly decreasing weight particle swarm optimization (LDWPSO) was used to optimize the arm angle to minimize the motion time of the manipulator. The kinematics calculation of the shoulder joint was verified by a combination of SOLIDWORKSTM and MATLABTM software. The kinematics calculation of the redundant manipulator was verified by MATLABTM. The linear, circular and 8-shaped motion trajectories were used to evaluate the proposed method in the simulation. The simulation results showed that the motion time with optimization of the arm angle was only 16%–30% of that without optimization. Furthermore, the proposed method was evaluated through real manipulator experiments, and the experimental results were similar to those in the simulation.