为了修正关节测试平台中由圆光栅安装偏心所产生的测量误差，建立了圆光栅偏心测角误差补偿模型并对安装偏心检测方法进行研究。首先，根据圆光栅测角与偏心参数间的几何关系，推导出圆光栅测量误差补偿模型。然后，描述了采用双读数头对比接收正弦信号间相位差,检测偏心参数的方法和原理； 通过合成信号的李萨茹图形，检测出关节测试平台内圆光栅的偏心距及偏心方向。最后，根据所推导的偏心测角误差补偿公式对测试系统进行修正。对比实验结果表明：修正后的圆光栅测角精度大幅提高，测量精度提高了近5倍，满足关节测试平台的测量精度要求。

To correct the measuring angle errors derived from the eccentricity of installing a circular grating in a manipulator joint test system, a model for compensation of grating measuring angle errors and the test method for installing eccentric errors are investigated. First, according to the relationship between angular error and eccentric parameters, the paper deduces the model of angular errors caused by install eccentricity. Then, it describes the method and principle to detect the grating eccentricity and eccentric direction by receiving phase errors of signals using two sensors in contrast. Based on the Lissajous plot generated by composite signals, the eccentric parameters of the grating in manipulator joint test system is measured. Finally, using the angle error formulas to compensate the measuring angle, the measuring system has been amended. The experiment shows that the amended angular accuracy has greatly improved, and the measurement accuracy is increased by nearly five times. It can satisfy the requirements of high accurate systems.