Research On Geometric Error Identification Of CNC Machine Tools Based On Grey Wolf Algorith

CNC machine tools are the workhorses of modern manufacturing,and are widely used in all walks of life with their advantages of high-precision and high-efficiency machining parts.However,with the rapid development of my country’s economy,improving the machining accuracy of existing CNC machine tools is an inevitable demand of the manufacturing industry.Geometric errors of the machine tool are an important factor affecting the machining accuracy,mainly due to defects in manufacturing and assembly.In order to analyze and research geometric errors more efficiently,accurately and comprehensively,and achieve too high machining accuracy of CNC machine tools.In this paper,the Hanchuan XK714 D three-axes CNC milling machine is used as the research object to complete the geometric error comprehensive model of the target machine tool and the parameterized model of the geometric errors,the regression coefficient optimization and error compensation experimental verification of the parameterized model based on the Grey Wolf Optimizer algorithm,and finally based on the parameters The result of the chemical model establishes the volumetric accuracy field of the target machine tool.The specific work content and results are as follows:(1)According to the principle of homogeneous transformation,the matrix representation form of motion transformation between different reference coordinate systems is explained.Alignment transformation theory uses mathematical modeling for analysis and research,and at the same time analyzes the error elements of the translational axis of the target machine tool.The theory of homogeneous coordinate transformation is used to derive the homogeneous transformation matrix of each kinematic chain of the target machine tool in the actual state and the error synthesis model of the three linkages.On this basis,a parameterized model of geometric errors is established based on the Chebyshev polynomial,and the parameterized representation of the comprehensive model of three linkage errors is obtained.(2)Briefly describe the basic principles and implementation steps of the Gray Wolf Optimization algorithm.Use QC20-W double ballbar to measure,calculate and analyze geometric errors of Hanchuan XK714 D three-axes CNC milling machine.The overdetermined equations of the parameterized model of the geometric errors are established through the collated error datas,the regression coefficients of the Chebyshev polynomial are obtained using the Grey Wolf Optimizer algorithm,and the geometric error curve related to the position is obtained based on the mathematical model of the geometric errors.(3)Calculate the compensation amount from the recognition result through forward kinematics,and modify it on the basis of the original G code.Collect data through double ballbar equipment,compare the two sets of experimental data before and after compensation,evaluate the accuracy of the model from the sum of the absolute value of the residual value and the sum of the square of the residual value.The average error is 0.010924 mm,and the error of the compensation result is average.The value is0.001783 mm.The change of the rod length of the double ballbar is reduced by 84.4%,which effectively improves the identification accuracy of the geometric error of the machine tool.Finally,the volumetric accuracy field of the target machine tool is established,analyzed from three directions,and the change rule of the geometric errors of the target machine tool is obtained.The corresponding volumetric error value can be obtained by inputting coordinate values at any positions of the volumetric accuracy field,which is convenient for future geometric analysis.Errors are studied in more depth.