Research On Geometric Error Edentification Of CNC Machine Tools Based On Composite Reference

The development level of CNC machine tools represents the development level of the national equipment manufacturing industry.Machining accuracy is the most important index to measure the working performance of CNC machine tools.The application of advanced detection technology,efficient and accurate identification of geometric errors and error compensation is one of the effective means to improve the machining accuracy and the performance of the machine tool.In this paper,based on parabolic and planar combination array,the detection technology is studied and the modeling and stepwise identification method for the geometric error of multi-axis CNC machine tools is proposed.The main work is as follows:1.The general modeling method of error propagation for CNC machine tools is studied.Summarize the modeling steps for different structures of CNC machine tools,and establish a comprehensive error model for the FXYZ type three-axis machine tools combined with the actual measurement system.2.A stepwise identification method based on parabolic and planar array is proposed.By using the optical sensor to measure the plane and parabolic surface of the combined array,the multiple parameter measurement of two-dimensional angle and two-dimensional displacement can be realized.The stepwise identification method fully combines the characteristics and advantages of the measurement system.By placing the reference on three different planes and measuring the composite surfaces according to the designed path,the angle errors can be directly identification and the linear errors can be indirectly identification based on the error model.The parameters of the geometric error curve can be identified quickly.3.Taking FXYZ type three-axis machine tool as an example,based on MATLAB,a simulation experiment combined with the actual situation is carried out.The simulation results show that the identification method is feasible and the error model is correct.4.Taking FXYZ three-dimensional displacement table as the experimental object,the geometric error identification experiment is completed based on the optical measurement system and L-type combined array.21 geometric errors are identified and the feasibility of the stepwise identification method is verified.Finally,the geometric errors are measured by laser interferometer.By comparing the direct measurement value with the identification value,the validity of the identification method is verified.The reason that affects the accuracy of the identification result is analyzed by combining the optical measurement system.