Abstract: Precession movement of bonnet tool polishing is realized by a spatial mechanism with 2 degrees of freedom (DOF). To the 2-DOF mechanism, the basic coordinate transformation is deduced and relationships among various parameters are analyzed with the theory of spatial mechanism. According to the requirements of precession, the motion equation of the spatial mechanism is developed. Simulation study is provided on the parameters of precession. Result shows that the 2-DOF movement which compositing the precession has specified laws. These results can be used for the further analysis and motion control of the mechanism.

Key words: Bonnet tool polishing, Movement modeling, Precession Spatial mechanism