数控机床进给系统装配误差建模及特征分析

摘要：
通过建立几何模型，分析了数控机床进给系统运动过程中由装配引起的误差特征，提出了表示其误差特征的综合表达式，将装配误差分为周期性分量和累积性分量.通过仿真分析，研究了装配误差在数控机床内置传感器中的信号特征，以及对进给系统运动精度的影响规律.结果表明：装配误差的周期性分量不影响进给系统的定位精度，但会导致进给系统在运动过程中产生周期性波动，且在频率调制的条件下其周期性波动幅值将增加；装配误差的累积性分量影响进给系统的定位精度，当与运动方向发生交叉时将产生累积方向的变化.同时，对某数控机床内置传感器的信号特征进行分析，并基于分析结果进行装配调整，从而降低了由装配引起的运动误差，提高了被测数控机床进给系统的精度.

Modeling and Characters Analysis of Assembly Error of Numerical Control Machine Tool

The assembly error characters of numerical control (NC) machine tool were studied using geometric model, and the integrated expression of assembly error characters was proposed, which contains periodic and cumulative components. The characters of assembly error in the signals of built in sensors were simulated, as well as the relationship with the motion precision of feed system. The simulations show that the periodic component does not affect the positioning accuracy but the dynamic precision, and the amplitude of periodic component could increase under the condition of frequency modulation. The cumulative component which converts direction at the cross point with motion direction has negative effects on the positioning accuracy. The signals of built in sensors of an NC machine tool were analyzed and the main factor that influences precision of feed system was found out. The precision of the tested NC machine tool was improved by modifying the assembly.