针对一类大直径精密转台不易采用传统方法实现高精度角度测量的问题，提出了一种基于激光追踪仪空间位置坐标测量的单自由度转台旋转角度的测量和补偿方法。首先依据“不共线的三点确定一个圆”的几何原理，建立了被测点空间位置坐标信息与转台角度之间的映射关系，并分析激光追踪仪的位置测量精度对转台角度测量精度的影响，据此提出了被测点半径长度和测量角度间隔的选取原则，以期充分利用激光追踪仪的位置测量精度实现转角误差的高精度测量；然后利用多项式插值方法获得转台转角误差随转角位形的变化规律，并将误差拟合为补偿函数嵌入控制器中，采用修正光栅输出示数的方式来实现转角误差的实时补偿。将文中方法实施于1台安装有圆光栅的精密转台的标定实验中，结果表明，文中方法可有效校正由圆光栅装配误差导致的角度定位误差，使其由标定前的40″降低至5″。%For large-diameter precision rotating platforms, to adopt traditional methods to implement high-precision angular measurement is difficult.In order to solve this problem, a rotating angle measurement and compensation method for a single degree-of-freedom rotating platform is proposed on the basis of the spatial coordinates obtained by using a laser tracker.First, on the basis of the geometry theorem that a unique circle can be determined by any three non-collinear points, a mapping function between the rotating angle and the spatial coordinates is formulated. Through a comprehensive analysis of the relationship between the measurement error of the laser tracker and the an-gular error of the rotating platform, a criterion for the selection of measured radius and angle interval is made so as to fully utilize the measurement accuracy of the laser tracker to realize a high-precision measurement of the rotating angle error.Then, the polynomial interpolation method is utilized to obtain the change laws of the rotating angle er-ror with the rotating angle position, and the real-time compensation of the rotating angle error is realized by embe-dding the fitted error mapping function into the control system and by modifying the output display of grating.Fina-lly, the proposed method is applied in a calibration experiment on a precision rotating platform equipped with circu-lar gratings.The results show that the proposed method can effectively reduce the angular error caused by the as-sembly error of circular gratings, which decreases from 40″to 5″.
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