Motion planning and experiment of a planar wire-driven parallel robot

A planar 1R2T wire-driven parallel robot was designed with the aim of realizing rehabilitation training. The effects on the system of the wires´ motion and the minimal tension force threshold were researched during the moving platform´s expected motion. The principle prototype is developed and some related experiments were done. The kinematics equations were established by the influence coefficients, which were depended on the layout scheme of the wires. By the kinematics equations, mapping relationship between moving platform´s motion and wire´s motion can be obtained. The moving platform´s dynamic equations by which the pull on the wire can be obtained were established based on force spiral and Alembert- Principle, and the method to decide the minimal tension force threshold is developed. Robot´s expected trajectory and the motions on each wire were simulated by MATLAB software. The simulated curve of wires´ force was got during a limit on the minimum tension of the wire. The position of the robot is calibrated based on the static balance theory and force closed-loop, and the trajectory control experiment is done. The results show that the motion planning method and the experiment calibration method is suitable for other wire-driven parallel system.