机床误差敏感度分析方法

Method of Error Sensitivity Analysis of Machine Tools

目前精度设计依然停留在以设计人员感官经验设计为主的层面,已开展的误差敏感度分析工作无法对精度设计提供直接的量化指导.针对上述问题,展开了机床误差敏感度分析方法的研究.首先,基于多体系统理论建立了数控机床的空间运动误差模型,同时构造了基于零部件公差的几何误差源参数的预估模型,在此基础上,进一步提出了基于部件运动增量的误差敏感度分析方法.以CA摆头五轴数控铣床为研究对象,以"S"试件为加工对象进行试验验证,利用基于机床部件运动增量的误差敏感度分析方法对五轴加工中心进行误差敏感度分析.结果表明:ε_y(x)、q_6~e、ε_x(x)、q_5~e、θ_C^e、ε_(zx)^(45)这6项误差源参数对应的误差敏感度系数之和为0. 95,其他误差源参数的敏感度系数之和仅为0. 05,因此该方法可以有效地识别出对数控机床加工精度影响较大的关键零部件,为提升数控机床的加工精度奠定了理论基础.

At present,the accuracy design remains at the level of the designer’s sensory experience,and the developed error sensitivity analysis cannot provide direct quantitative guidance for accuracy design.In view of the above problems,the error increment equation was first established based on the theory of the multi-body system.Meanwhile,the prediction model of component tolerance and geometric error source parameters was constructed.Furthermore,a method of error sensitivity analysis based on component motion was proposed.Taking CA swing head five-axis NC milling machine as the subject,and taking'S'specimen as the object of processing,the error sensitivity analysis of five axis machining center was carried out by using the method of error sensitivity analysis based on the increment of machine tool component motion.The experimental results show that the sum of the error sensitivity coefficients of the six error source parametersεy(x),q6e,εx(x),q5e,θCe andεzx45 is 0.95 and the sum of sensitivity coefficients of other error source parameters is only 0.05.Therefore,this method can effectively identify the key parts that affect the machining accuracy of CNC machine tools,and lay a theoretical foundation for improving the machining accuracy of CNC machine tools.