Kinematic Analysis and Simulation of a 7-DOF Cable-Driven Manipulator

To improve the load capacity of the manipulator, based on the geometry analysis and screw theory, this paper is focused on the configuration design, cable-driven manner, and kinematics control for a cable-driven 7-DOF manipulator. First, aimed at the choice of cables-driven manners, a cable-driven mechanism that is coupled between elbow and wrist, and between shoulder and elbow is designed. Second, taking the 7-DOF joints such as the shoulder, elbow and wrist as medium, the relationship between the end-effector and driven cables is analyzed, i.e. through considering the relationship among the end-effector´s pose and joint angles first for the manipulator, and then considering the relationship among joint angles and corresponding cable lengths, the kinematics of cable-driven manipulator can be solved. Lastly the simulation is realized. The simulation results show that the curves of manipulator´s joint angles and cable lengths are very smooth, and the error between actual trajectory and ideal trajectory of the end-effector is very small. These prove that the proposed algorithms are correct, the cable-driven manipulator runs well, and proposed approach can effectively overcome the negative effects from general robot brought by its deadweight.