数控机床几何精度的位姿测量原理
Pose Measuring Principle of Geometric Accuracy of Numerical Control Machine Tools

为了获得数控机床全部的几何误差信息,根据激光跟踪仪的三维空间测量特性,提出一种数控机床几何精度位姿测量原理和几何误差分离原理。借助于一台固定安装于机床上的数控精密转台和一台激光跟踪仪获得机床运动轴的位姿信息,然后辨识出机床各项几何误差。首先,详细描述了位姿测量方法的基本原理,给出了平动轴误差测量数学模型,包括测量点、基点空间坐标的标定原理以及姿态偏差的获取步骤;然后,根据解析几何知识先后分离出3项转角几何误差和3项位置几何误差,并综合得出单个运动轴6项几何误差分离模型;最后通过数值模拟、测量实验以及对比实验验证了该原理的可行性和准确性。实验表明,采用位姿测量原理可以在2 h内实现一台3轴高速数控铣床的精度检测,并准确分离出各项误差。位姿测量原理具有很高的测量精度与效率,解决了基点标定难题,且标定精度更容易提高。该原理为数控机床精度检测提供了一种新的思路,应用前景广阔。
In order to obtain all geometric errors of numerical control (NC) machine tool, according to the 3D measurement characteristic of laser tracker, the pose measurement principle for geometric accuracy detection of machine tool and separation principle for geometric error are developed. By means of NC precise turntable fixed on machine tool and a laser tracker, the pose information of translational axis can be calculated, then the geometric errors are determined. First, the pose measurement principle and measurement mathematical model of linear axis are developed in details, including calibration principle of measuring points and base stations, and the acquisition procedures of pose deviation. Then, the three angular errors and three linear errors are identified successively and geometrically, and the comprehensive error identification model for single axis is determined. At last, the feasibility and veracity are verified by simulation experiment, measurement experiment and comparative experiment. Results of experiments show that the proposed method is able to complete the precision detection of a 3？？axis milling machine within 2 h, and the errors are identified successfully. This measurement principle has short measurement time and high precision, and solve the calibration problem of base station with higher precision. The pose measurement principle provides a new method for machine tool error detection with an extensive application prospect