【作者】 邱立伟；

【导师】 林洁琼；

【作者基本信息】 长春工业大学 ， 机械设计及理论， 2011， 硕士

【摘要】 高档数控机床,特别是精密多轴数控机床,是衡量一个国家制造业水平的重要标志,在诸多制造业有着十分广泛的应用需求。提高机床精度有两种方法。一种是误差防止法(Error Avoidance),即通过提高数控机床的零件结构设计、制造精度和装配水平来尽可能地消除误差源。另一种是误差补偿法(Error Compensation),即通过对机床工作及加工过程的误差分析、建模与补偿来改变坐标实际运动量达到理想的运动轨迹,从而实现不使用精密加工设备的精密加工。目前,通过误差防止法来提高加工精度的误差避免方法越来越难以实现,造价成本也越来越高昂。因此,发展数控机床误差补偿技术的呼声愈来愈强烈。本文首先基于多体系统运动学理论,以一台四轴加工中心为对象,建立了包含几何误差和热变形引起的误差的综合数学模型,深入分析并解决了加工中心的交换工作台站的误差传递、各轴热漂移误差影响等关键问题。该误差模型为实现加工中心的精确补偿提供了坚实的理论基础。其次,创新性地提出了基于改进的LS-SVM的数控机床定位误差建模预测方法。利用激光干涉仪进行了XYZ三轴的定位误差测量实验,采取补偿反向间隙和单项定位误差的方法进行初步补偿；提出了基于加权最小二乘支持向量机的机床单轴定位误差建模方法及模型参数优化方法,并从理论上验证了模型的精确性及可行性。最后,通过补偿实验验证了基于加权LS-SVM建立的误差模型的精确性及补偿方法的可行性,用该方法对数控机床各轴进行预测补偿,能有效提高数控机床的加工精度。另外,本文还创新提出了面向误差实时补偿技术的LS-SVM建模补偿的方法,研究并提出了误差实时补偿程序实现流程及补偿控制策略。更多还原

【Abstract】 High-grade nc machine tools, especially precision multi-axis nc machine tools, is an important symbol to measure manufacturing levels of a country, it has extremely extensive application requirements in many manufacturing. Improving machine precision have two kinds of methods. One kind is Error Avoidance method, namely through improving CNC machine parts structure design, manufacture precision and assembling levels to eliminate Error sources as far as possible. Another kind is Error Compensation method, namely not changing the original machine structure and texture, through the Error sources analysis of machining process, modeling and compensation,change the actual activity to achieve ideal exercise trajectory, realized without the use of precision machining equipment precision machined. At present, through Error Avoidance method to improve the precision components manufacturing error of the machining accuracy of realization become more and more difficult to avoid methods, cost more and more is also high. Therefore, the development of CNC machine error compensation technology calls for stronger and stronger.This paper firstly based on multi-body system, with an four axis machining center for object, established an comprehensive mathematical model contains geometric error and error caused by thermal deformation, thoroughly analysed exchange work stations error on transmission of machining center and hot drift error influence on axes and other key problems, and solved the problem in the course of modeling. This error model provided a solid theoretical basis for precise compensation of machining center.Secondly, innovatively put forward positioning error modeling and forecasting method for CNC machine based on improved Least Squares Support Vector Machine (LS-SVM), performed XYZ triaxial positioning error measuring experiment by using laser interferometers, adopted compensation method of reverse clearance and single positioning error to compensate for position errors, put forward modeling method for positioning error based on weighted LS-SVM and the model parameters optimization method, and proved theoretically the accuracy and feasibility of the model.Finally, by the compensation experiments proved accuracy of error model based on weighted LS-SVM and feasibility of compensation method, and prediction and compensation by this method for CNC each axis, can effectively enhanced the CNC machining accuracy.This paper also innovatively proposed modeling compensating method by LS-SVM facing error real-time compensation technology, researched and put forward realization process of real-time error compensation program and compensating control system.更多还原