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.