大型双柱立车误差建模及分析

Error synthesis model and analysis for heavy-duty CNC double column vertical lathe

针对某工厂大型双柱立车,采用多体系统运动学理论描述其结构关系,以齐次坐标变换法推导误差综合运动学数学模型,同时给出了机床误差总体矢量图。该数学模型可包含机床各运动轴的几何误差、热误差以及切削力导致的多项误差元素。利用误差综合模型,并通过对各项误差元素求偏导数,分析和比较了误差元素对加工误差的影响程度和作用方式。模型的建立和误差元素分析为机床实施误差补偿以提高加工精度,以及设计合理测量系统以实时监测机床工作状态,提供了理论依据。

The kinematic structures of a CNC double column vertical lathe have been formulated by multi-body system theory,and the error synthesis model has been derived by homogeneous coordinate transformation method.In this model,geometric error,thermal error and deformation induced by cutting force are all concerned.The relationship between error components and volumetric error has been analyzed and compared by the partial derivative for error components.Error modeling and analysis provide the theory foundation for the further error compensation to increase the machine accuracy,and for the establishment of measurement system to monitor the machine condition.