Error Identification And Compensation Of CNC Machine Tool’s Linear Axes

CNC machine tools play an important role in the continuous development of the equipment manufacturing industry, and its precision usually represents the development level of manufacturing industry. In the process of manufacturing and assembling, the geometrical error of the moving parts of the CNC machine tools is inevitable, which has seriously affected the final machining accuracy. Modeling, identification and compensation of geometric errors of the linear axes of CNC machine tools is focused on by this paper. A set of MATLAB based linear axes error identification and compensation software is developed and verified by experiments.The dissertation analyzes the CNC machine tool geometric error sources, according to the definition of perpendicularity and straightnes s. By taking 21 perpendicularity errors of linear axes into straightness errors, 18 new kinematic and geometric errors generate. The deviation value between the new machine tool tip and workpiece relative displacement caused by 18 geometric er rors is the geometric error. Combined with the movement of the CNC machine tool, a new error model is established by using the homogeneous coordinate transformation matrix. The high order error terms are neglected, and the relationship between the geometric error element model and the error quantity is established. An improved multi-step identification method based on the new error model is used to identify the position error and the straightness error of the machine tool. The verticality and unidirectional rotation error are calculated by the definition of error elements. The rationality of the new error term is derived from the measurement of the geometric error element and the radial error of the circular trajectory. We developed a set of measurement, identification and compensation software combined identification and measurement principle. The new step identification of CNC machine tools is carried out. The main error element model is identified successfully, and the position error is verified by the Renishaw XL80 laser interferometer.Based on the new error synthesis model, a new method is proposed to compensate the straight line segment. In the XOY plane, the plane grating is used to carry out the experimental verification. The accuracy and speed of the error compensation of CNC machine tools are improved by the method of the identification and compensation of the linear axes in this paper.