Screw theory based geometric error modeling of five-axis machine tools

• 1、College of Mechanical Engineering, Zhejiang University, Hangzhou 310027

Abstract：One geometric error modeling of five-axis machine tools based on screw theory is proposed for solving the issues of geometric errors models using homogeneous transformation matrix. At first, the screws are established to describe the motions of linear axes and rotary axes based on the geometric meaning of screws. And the exponential matrices are established. One twist not only can represents the location of the axis, but also expresses the motion of the axis. Then, the six geometric errors of each axis are divided into three groups due to their error directions. Each group is established as one error screw. What's more, the detailed topological structure of the machine tool is introduced to manage those screws in order to obtain the integrated geometric error model of the machine tool. Only one global reference coordinate frame is defined during the whole modeling. Finally, the geometric error distribution of the workpiece are calculated based on the established error model and the NC code of the workpiece. The error distribution can provides a reference for the later error compensation of machine tools.

Keywords： five-axis machine tools geometric errors error modeling screw theory