Design And Optimization Methods Of CNC Machine Tool Kinematic Chain Based On Position Solving And Error Analysis

CNC machine tool is the key equipment of modern manufacturing industry.The design ofkinematic chain of CNC machine tools is an important part of the whole machine design.Aimedat the shortcomings of CNC machine tool kinematic chain design,in this paper,design andoptimization methods of CNC machine tool kinematic chain based on position solving and erroranalysis are proposed.For a workpiece or a group of workpieces to be machined,the toolposition vector set is obtained by tool path and tool axis vector planning.By solving the toolposition-motion function equations,all CNC machine tool kinematic chains satisfying positionrequires are obtained.According to the principle of multi-body kinematics,the model ofmachine ultimate error is constructed.By analyzing and comparing the matrix error and spinparameters of different kinematic chains,the accuracy of kinematic chains are improved.Basedon the static finite element analysis of CNC machine tool,the error sensitivities of the motionaxes components are obtained by solving the error component equations.The optimizedkinematic chains are optimized based on the sensitivity analysis results.Based on the theoreticmethods and techniques proposed in this paper,a kinematic chain design system for CNCmachine tools is developed.This paper is divided into six chapters,and the main contents are asfolllows:In Chapter 1,the reviews of kinematic chain deisgn is given.The background andsignificance of the research are expounded,and the main contents and framework of this paperare introduced.In Chapter 2,a kinematic chain design method of CNC machine tools based on positionsolving is proposed.For a given workpiece or a group of workpieces to be machined,accordingto the tool path and tool axis vector planning,the tool position vector set are obtained.Thekinematic function matrixes of the kinematic chain are constructed to represent the movementfunction of the kinematic chain.By constructing and solving the tool position-motion functionequations,all kinematic chains satisfying position requires can be obtained.In Chapter 3,an ultimate error analysis method for precision design of CNC machine toolkinematic chain is proposed.Define the ultimate error state of CNC machine tools.According tothe principle of multi-body kinematics,the ultimate error model of machine kinematic chain is constructed and the ultimate error matrix of the kinematic chain is obtained and analyzed theoretically.Based on the screw theory,the ultimate error matrix is transformed into spin quantity and the errors of different kinematic chains are compared.By comparing and analyzing the ultimate errors of different kinematic chains,the bad chains with larger errors are eliminated and the precision of the kinematic chains are improved.In Chapter 4,a kinematic chain optimization method of CNC machine tools based on error sensitivity analysis is proposed.Firstly,a method of solving the error sensitivity based on the finite element analysis of CNC machine tools is presented.The machining error model of kinematic chain of CNC machine tools is established,and error sensitivity can be obtained by solving the error component equations.Then,based on the results of error sensitivity analysis,the kinematic chain of CNC machine tools is optimized to decrease the error sensitivity.In Chapter 5,a kinematic chain design system for CNC machine tools is developed based on the theoretic methods and techniques proposed in this paper.The system is applied to the kinematic chain design,analysis and optimization process of a five-axis CNC machine tool to verify the feasibility of the method.In Chapter 6,the main content and innovation of this article are summarized,and the future work and research direction are discussed.