基于多体运动学理论的机床误差灵敏度分析

Error sentivity analysis of machine tools based on multi-body kinematic theory

针对机床加工误差出现后如何查找影响加工精度的关键因素这一问题,提出了一种基于多体系统运动学理论的机床误差灵敏度分析新方法。该方法首先利用多体系统运动学理论,将机床抽象为多个运动刚体,在各个刚体上建立体参考坐标系和运动参考坐标系,将刀具中心点和工件加工点分别通过各自坐标系描述到系统坐标系,以此方法建立约束方程并求解加工误差;然后通过对误差求导的方式获得误差参数的灵敏度并建立误差参数影响分析模型。实例的分析和计算证明,该方法可以有效地查找对机床误差影响较大的因素,从而可为机床设计者和使用者提供有效的机床改进理论基础。

In order to determine the key factors which have an impact on the machining accuracy of a machine tool after its machining errors occur, a new method analyzing the sensitivity of machine tool errors based on the theory of multi-body system kinematics is proposed. Firstly, the method assumes a machine tool to be several rigid bodies according to the theory of multi-body system kinematics, establishes the body reference coordinate system and the kinematic reference coordinate system on each rigid body, and constructs the constraint equation by using the method of describing the center of the tool and the machining point in the system coordinates to solve the machining errors of the machine tool. Then, it gives the sensitivities of error parameters by taking derivative of errors and establishes the impact analysis model. The calculation and analysis for an example show that when using the method the key factors that have significant influence on machine tool errors can be identified efficiently. It can provide the theoretical basis for designers and users to improve machine tools.