Research And Application On Geometric Error Modeling And Parameters Traceability Of CNC Machine Tools

CNC machine tools have a pivotal position in the national economy, and the high-end CNC machine tool is an important manifestation of national competitiveness. Both geometric error modeling and analytic error tracing are important parts in accuracy distribution and design of CNC machine tools. Combined with major national science and technology projects, this paper has studied on three methods and technologies:the CNC machine tools’geometric error modeling based on the multi-body system theory, the machine precision parameters traceability technology based on sensitivity analysis, multi-objective optimization of the machine precision distribution based on SPEA2+algorithm, and then developed the corresponding function module, which verified the feasibility of the methods described above.The main content of this theses were listed below:Chapter I described the background and concepts of the related technologies, analyzed the research status of the three methods described above, discussed two problems of the prior technology and then list the content and organizational structure of the paper.Chapter II introduced the CNC machine tools’geometric error modeling based on the multi-body system theory. Described in detail the basic principles and specific methods of using multi-body system theory to create the CNC machine geometric error modeling. Through described the topology of CNC machine components and established a generalized coordinate system, which used to express coupling relationship among error amounts of CNC machine parts in the actual situation, we could deduce feature matrix of the machine two adjacent bodies which moved relatively and establish the CNC machine precision model. Finally, took precision design and distribution of TGK.46100as an example to verify the method described above.Chapter III proposed the CNC machine precision parameters traceability technology based on sensitivity analysis. For the needs of making the geometric error of the CNC machine specific and explicit, proposed a method to analyze CNC machine precision sensitivity based on the direct matrix differential method. According to the detection values of each error term of CNC machine which was determined through processing a specific test pieces, calculated the whole machine sensitivity model and sensitivity coefficient of each geometric error by using sensitivity analysis technology. Then we could accomplish analytic error tracing and initial accuracy distribution. Finally, took analytic error tracing and initial accuracy distribution of TGK46100as an example to introduce application process the method described above.Chapter IV researched on multi-objective optimization of the machine precision distribution based on SPEA2+algorithm. Introduced on the cost-geometric error/reliability- geometric error and soundness-geometric error of the machine precision modeling methods, and the three models (cost-geometric error model/reliability-geometric error model/soundness-geometric error model) are established; the definition and mathematical description of SPEA2+algorithm are summarized, and gave the concrete steps of using SPEA2+algorithm for solving multi-objective optimization problem. Finally, took precision distribution optimization of TGK46100as an example to introduce application process the method described above and got the final optimization results of TGK46100, so we can verify the feasibility of the method.Chapter V according to the theory and methods of the paper and combined with the participation of CNC machine project developed the error tracing and precision distribution optimization of CNC machine tool system. The system is used in precision allocation process of CNC machine tool design, to verify the theoretical method proposed in this paper is feasibility and practicality.Chapter VI concludes the paper and outlines the used theories. Pointed out that innovation, the difficulties and shortcomings of this paper’s research and prospected the direction for future work.