【作者】 张变霞；

【导师】 沈兴全；

【作者基本信息】 中北大学 ， 机械制造及其自动化， 2008， 硕士

【摘要】 加工精度是机床最重要的性能指标之一。本课题运用多体系统运动学为核心的误差分析理论体系,对三轴数控机床精度问题进行了系统、全面的分析,并重点在数控机床误差测量、误差分析建模、误差辨识以及软件误差补偿等方面开展深入研究,通过机床误差模型,揭示误差从机床零部件到被加工零件的传递规律,给出了精度预测,并对机床进行了软件误差补偿以提高加工精度。本文主要从以下几个力面的内容进行了研究和探讨:1.研究了机床的测量方法,比较了数控机床传统的和先进的误差测量工具和测量方法,并对球杆仪、激光干涉仪等先进测量仪器的测量原理和应用方法进行了分析总结。2.研究了机床的精度分析的基本理论及其评定标准,对多体系统运动学以及基于该理论的机床误差建模、误差辨识及误差补偿的方法作了系统的探讨。数控机床误差参数的正确辨识是数控机床补偿的必要前提条件。3.详细分析了12线误差分析方法,应用误差辨识软件,解得各测量点的十八个误差参数,再根据实际情况求解三项垂直度误差,最后得到了所有的21项几何误差。4.建立了三轴数控机床的通用精度分析模型,还以XK713三轴数控机床为例给出了理想运动模型、有误差运动模型和空间误差模型等的分析表达式。基于直接计算法修正理论数控指令的软件误差补偿,从模型的选择,参数的识别,数控指令的转换都实现了人机交互模式,应用起来直观易用,操作方便。通过此项技术的误差补偿,机床的各项误差都有所降低,达到了提高机床加工精度的目的。但是本课题的成果尚未应用到生产实际中,在今后的研究中,还要进行大量的实验,取得大量的测量数据,为今后该方法的实际应用奠定基础。更多还原

【Abstract】 The machining accuracy is one of the most important performance indexes for machine tools. Firstly, this dissertation details the accurate problems of the multi-axis CNC machine tool based on the precision analysis theory of kinematics for multi-body system (MBS) systemically. Secondly, it lays the strong emphases on the researches of the error analyzing and predicting, software error compensating and so on. With the precision model of the multi-axis CNC machine tools, their error transferability rules from the parts to the machined work pieces are opened out, their machining accuracy predicted and their errors compensated based on software to increase their machining accuracy. The following issues are mainly studied and addressed in this thesis:1. The commonly used measurement of the parallel machine and corresponding measure tool were studied. The measurement theory and application methods of some advanced measure instruments were analyzed, which are DBB (double ball bar); the dual frequency laser interferometer,2. Due to taking full advantages of the development results of computers, the MBS theories have coruscated out of new magic power, showing their good universality, systematization and convenience for the researches of the kinematics and dynamics of MBS. Thus, this paper gives a systematic and in-depth study on the MBS kinematics theory and the methods of precision modeling, error identification, accuracy prediction, and error compensation based on the studied theory.3. After establishing the precision model of machine tools, the measurement and evaluation of their error parameters have been started. There are many kinds of error parameters in the machine tool to influence its machining accuracy. The recognized strategies of error measurements and evaluations for machine tools are introduced. After that, this paper has detailed a new method defined as twelve-line method for the sake of making the most of double-frequency laser interferometers to measure and evaluate 21 geometric errors of three-axis system. Based on these researches, the problems of the error measurement and evaluation of machine tools in the application process of MBS theories are resolved perfectly.4. This paper put forward index systems of machining contour errors, expatiated the mapping relation from position errors to contour errors, and established the idle model from the errors of the components of machine tools to machining errors so that the machining accuracy estimates can be realized accurately. A key point of this software error compensation is that how to obtain the numerical control instructions to compensate the known errors. Selecting the model, identifying the parameters and transferring the NC command with the help of the dialogue model between human and computer. The transfer of NC command can be directly turned into the files of NC command compensated by the computer, so it is operated very conveniently.According to the error compensation of this technology, all kinds of the errors of the NC have been lower than before, reaching the aim of approving the accuracy of processing of NC. But the results of the programmer have not been used in practice, in the near future of researching, we have to do lots of experiments, and get a large quantity of useful dates in order to make the foundation of future practical application of this method.更多还原