Design And Analysis Of A Six-degree-of-freedom Hybrid Manipulator Driven By Three Motors

The multi-degree-of-freedom manipulator with less motor drive is mainly used in the aerospace field.This paper proposes a mechanical motor with less motor drive.The mechanical arm is driven by three motors.It realizes six-degree-of-freedom movement of the end of the manipulator through the clutch mechanism of the clutch brake,gear and synchronous toothed belt,and has a small number of electrical components.The reliability of the electrical system is high.A six-degree-of-freedom hybrid manipulator configuration with a 3-1-2 layout is designed.The shoulder joint of this manipulator adopts a three-degree-of-freedom orthogonal parallel mechanism,the elbow joint adopts a single-degree-of-freedom rotation mechanism,and the wrist joint adopts two-degree-of-freedom orthogonal parallel mechanism,each joint is driven by one motor.The feasibility of the less motor drive scheme is demonstrated from two aspects: control mode and weight of the manipulator.The positive and negative solutions of the mechanism position are analyzed,and the workspace has been drawn by using the space boundary point search method.The workspace volume is used as the evaluation index.The influence of the mechanism size parameters on the evaluation index is analyzed through univariate analysis.Then a set of reasonable mechanism parameters are given.The virtual prototype is designed by ProE software.The velocity and force Jacobian matrix of the whole machine have been deduced,then the velocity of the shoulder and wrist joints and the distribution of force transmission are analyzed.The dynamic model of the manipulator is established by using the Lagrange method.The dynamics simulation has been done by using ADAMS software,then the correctness of the dynamic model is verified.The movement characteristics of the manipulator are analyzed.Considering the path length,time-consuming,energy consumption and impact factors,the comprehensive evaluation index has been established.The obstacle avoidance path of this kind of motor-driven hybrid manipulator is planned by using the constrained artificial potential field method.The research results in this paper lay a theoretical foundation for the development and practical application of this kind of multi-degree-of-freedom hybrid manipulator with less motor drive.