A Dimensional Parameter Optimization Method of Manipulator to Improve Manipulability

This paper mainly focuses on a method to optimize dimensional parameters of a manipulator. Firstly, the configuration of the manipulator is analyzed. For a manipulator the last three joint axes of which cross a point, the kinematic analysis can be broken down into position analysis and posture analysis through decoupling. Then, the dexterous workspace volume is used as an indicator to evaluate the manipulability of a seven degree-of-freedom (DOF) manipulator. The dexterous workspace volume of AUBO seven DOF manipulator can be simplified to discuss on a two-dimensional plane based on its kinematic characteristics. Through theoretical analysis, all the possible positions of the wrists for a corresponding point in the dexterous workspace should be inside the workspace of the wrist. When keeping the sum of all the link length of the manipulator constant, there exists a change trend of each link length to improve the manipulability by maximizing the volume of the dexterous workspace. Through simulation, the optimization result is verified. The conclusion lays the foundation for the design of seven DOF manipulator in the future.