重型数控落地铣镗床综合误差补偿研究

发布时间：2018-03-06 11:20

  本文选题：落地铣镗床　切入点：综合误差建模　出处：《哈尔滨工业大学》2015年博士论文　论文类型：学位论文

【摘要】：重型数控落地铣镗床具有开放式结构,适合大型零部件高精度平面和孔系的加工,但是精度不足限制了该机床的应用。针对该机床空间误差进行控制和补偿有着重要的现实意义和研究价值。然而对该类机床的精度检测和误差补偿技术的研究还不够完善。本文首先对重型数控落地铣镗床进行了误差溯源分析,在提出了该机床的几何误差和热误差的耦合方式的基础上,建立了包含几何与热耦合误差和动态跟踪误差的综合误差模型,并推导了机床误差敏感系数矩阵。分析误差测量不确定度并提出测量精度保持方法。依据统计方法得到了激光跟踪仪测量要素的不确定度分布。通过实验研究得出了机床低温升时以热漂移误差为主要热误差形态的特性,建立了空间测量点热漂移误差模型,测量得出了机床重复定位误差的分布,综合跟踪仪和机床对测量不确定度的影响,依据Monte Carlo法评估了测量不确定度。为降低测量不确定度,优化了跟踪仪的测量站位,同时提出了工作空间分割和多站位测量方法,通过实验验证了上述方法对降低测量不确定度的有效性。在分区测量空间误差的基础上辨识几何误差。依据误差敏感系数矩阵分析得到了空间误差对几何误差的敏感性以及机床空间尺寸(Y轴、W轴、Z轴坐标和刀具尺寸)对敏感性的影响规律。在此基础上提出了采用激光跟踪仪的四线制测量与粒子群优化算法相结合的几何误差辨识方法。该方法引入了粒子群优化算法,辨识得到了垂直度误差、线性位移误差和转角误差。以激光干涉仪的测量结果为依据对比验证了上述误差辨识方法的有效性。为辨识动态跟踪误差建立了机床的跟随误差和圆轨迹轮廓误差模型。测量了机床X轴和Y轴联动的圆轨迹误差,分析得到圆轨迹误差随机床运动参数的变化规律,基于此变化规律研究了动态跟踪误差和准静态误差的解耦方法。结合圆轨迹轮廓误差模型和解耦得到的动态跟踪误差,辨识得到了机床运动轴的参数,通过试验验证了预测模型精度。基于辨识得出的综合误差模型参数建立了误差模型,验证了综合误差模型预测精度,并着重开展了基于有限元方法(ANASYS软件)和实验方法的机床Z向空间误差溯源分析,建立了主轴箱体结构热变形的误差尺寸链,阐述了Z向热漂移误差的产生原因。针对热漂移误差设计开发了基于因瓦合金杆的热误差实时测量与补偿系统。本文采用自主开发的适用于西门子数控系统的误差补偿器,补偿机床静态空间误差,实验验证了补偿的有效性。依据辨识得到的伺服参数,调整系统动态适配时间,机床圆轨迹误差降低了80%。开展了热漂移误差补偿装置在西门子数控系统中的应用方法研究,补偿前后的对比结果验证了补偿系统的稳定有效性。最终,将误差补偿技术综合应用到重型数控落地铣镗床中,补偿效果显著,加工误差降低35%以上。
[Abstract]:The heavy-duty NC floor milling and boring machine has an open structure, which is suitable for the machining of large parts with high precision plane and hole system. However, the lack of precision limits the application of the machine tool. It has important practical significance and research value to control and compensate the spatial error of the machine tool. However, the research on the accuracy detection and error compensation technology of this kind of machine tool is also made. In this paper, the error of heavy NC ground milling and boring machine is analyzed. On the basis of the coupling mode of geometric error and thermal error of the machine tool, a comprehensive error model including geometric and thermal coupling error and dynamic tracking error is established. The error sensitivity coefficient matrix of machine tool is derived, the uncertainty of error measurement is analyzed, and the measurement precision preserving method is put forward. The uncertainty distribution of measuring elements of laser tracker is obtained by statistical method. The characteristic that the thermal drift error is the main thermal error form when the machine tool rises at low temperature is given. The thermal drift error model of spatial measurement points is established, and the distribution of repeated positioning errors of machine tools is measured. The influence of comprehensive tracker and machine tool on measurement uncertainty is obtained. The measurement uncertainty is evaluated according to Monte Carlo method in order to reduce the uncertainty of measurement. The measuring station of tracker is optimized, and the method of workspace segmentation and multi-station measurement is put forward. The effectiveness of the above method in reducing the uncertainty of measurement is verified by experiments. The geometric error is identified on the basis of the spatial error of the zone measurement, and the geometric error of the spatial error is obtained by the analysis of the error sensitivity coefficient matrix. The sensitivity, the space dimension of machine tool, the coordinate of Z axis of Y axis and the size of cutting tool) affect the sensitivity. On the basis of this, the geometry combining four-wire measurement with laser tracker and particle swarm optimization algorithm is put forward. This method introduces particle swarm optimization (PSO) algorithm. The verticality error is identified. Based on the measurement results of laser interferometer, the validity of the above error identification method is verified. In order to identify the dynamic tracking error, the tracking error and the circular trajectory error of the machine tool are established. Differential model. The circular trajectory errors of X-axis and Y-axis linkage of machine tools have been measured. The variation law of circular trajectory error with machine tool motion parameters is obtained. Based on the variation law, the decoupling method of dynamic tracking error and quasi-static error is studied, and the dynamic tracking error obtained by decoupling is combined with the circular trajectory contour error model and decoupling. The parameters of the moving axis of the machine tool are identified, and the accuracy of the prediction model is verified by experiments. The error model is established based on the parameters of the comprehensive error model obtained from the identification, and the prediction accuracy of the comprehensive error model is verified. Based on finite element method ANASYS software) and experimental method, the error dimension chain of the thermal deformation of spindle box structure is established, which is based on the analysis of the Z-direction spatial error of the machine tool, which is based on the finite element method (FEM) and the experimental method. This paper describes the causes of the Z-direction thermal drift error, designs and develops a real-time measurement and compensation system for the thermal error based on the Intile alloy rod, and adopts an error compensator developed by ourselves for Siemens numerical control system. The validity of the compensation is verified by experiments. According to the identified servo parameters, the dynamic adaptation time of the system is adjusted. The error of circular trajectory of machine tool is reduced by 80%. The application method of thermal drift error compensation device in Siemens numerical control system is studied. The comparison results before and after compensation verify the stability and effectiveness of the compensation system. The error compensation technology is applied to the heavy NC ground milling and boring machine. The compensation effect is remarkable and the machining error is reduced by more than 35%.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TG659
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本文编号：1574620