Trajectory tracking control for a 7-DOF cable-driven modular manipulator

This paper presents a hybrid-driven approach with cable-driven and convention-driven designs for a 7-DOF manipulator. This approach combines the advantages of both cable-driven parallel mechanism and modular serial structure, so that the workspace of the hybrid-driven manipulator is larger than that of the conventional cable-driven design. The hybrid mechanism design of the manipulator is presented firstly, which has a modular serial structure in shoulder joint and a cable-driven structure in elbow and wrist joint respectively. Then the forward kinematics of the manipulator is solved with geometry analysis. After relationship between the cable length and the joint angle is analyzed, the velocity analysis and incremental displacement analysis are respectively employed to calculate the inverse kinematic solution. Finally, a straight-line motion trajectory tracking for the hybrid cable-driven manipulator is realized with VC + + software, and the effectiveness of proposed approach is verified with simulation.