转轴径向运动误差干涉测量的信号处理方法

转轴径向运动误差是转轴的重要误差项之一，严重影响数控机床等转轴相关设备的精度和性能。利用激光干涉配合伺服转轴可以实现转轴径向运动误差的测量，但由于待测转轴和伺服转轴的自身转速不匀、伺服响应延迟、跟踪不稳等原因，干涉测量信号存在持续微幅相位抖动，进而造成非线性误差难以有效修正，相位解算精度不高，测量误差大。针对这一问题，提出一种零值截取-阈值判定的干涉信号处理方法，成功消除了相位抖动的影响。设计并搭建了一套转轴径向运动误差的激光干涉测量装置，针对实测信号的处理结果表明，相比于传统修正方法，文中提出的修正方法使得转轴径向运动误差干涉测量信号解算的重复性由4.8 μm减小到0.2 μm，与标准仪器的对比误差由3.5 μm降为2 μm。

Signal processing method for measuring the radial motion error of rotary axis by interferometry

The radial motion error is one of the most important errors of rotary axis, which seriously affects the precision and performance of CNC machine tools. Using laser interference with reference rotary axis can achieve measurement of radial motion error. Neither target or reference rotary axis is ideal, there are some restrictions like uneven speed, response delay and unstable tracking. These restrictions cause phase jitter and make the non-linear correction difficult. It will affect the phase calculation accuracy of the interference signal. In order to eliminate the influence of phase jitters, a type of signal processing method is proposed. The paper designs and builds a set of laser interference measuring device for measuring the radial motion error. Compared to the traditional correction method, the proposed method reduces the measurement repeatability from 4.8 μm to 0.2 μm, and the error compared with the standard instrument is decreased from 3.5 μm to 2 μm.