Abstract: To solve the problems that the relationship between the input and output velocity of the five axes parallel machine tool can not be obtained directly just using the velocity vector-loop method for the non-independent movement of its angular velocity’s components, and the existence of constrained output moment which can not be balanced by the input forces would increase the difficulty in analyzing the relationship between the input forces and output force and moment. The movement characteristic of the moving platform is analyzed and the relationship of the angular velocity’s components is found. Then the relationship between the input and output velocity of the five axes parallel machine tool is derived. Analyzed the constrained output moment which contributes no virtual work and taken out it from the output moment the relationship between the input forces and output force and moment of the five axes parallel machine tool can be obtained according to the principle of virtual work. The method presented has great reference value for the further study of 5-DOF parallel machine tools or parallel mechanisms.

Key words: Non-independent movement, Parallel machine tool, Principle of virtual work, Velocity vector-loop method