Stiffness analysis of a wire-driven parallel manipulator

The positioning accuracy of a wire-driven parallel manipulator mainly depends on its stiffness when forces act on a mobile platform. In this paper the stiffness of the wire-driven parallel manipulator is theoretically studied, and a whole analytic expression is deduced based on the differential transformation principle. The stiffness matrix of the wire-driven parallel manipulator is composed of two parts which are structural parameter stiffness matrix and wire tension stiffness matrix. The simulation results show that the stiffness of the manipulator relies heavily not only on its structural parameters, but also on the tension of wires. The stiffness of the wire-driven parallel manipulator can be adjusted by changing the wire tension when its structural parameters are unchanged.