轴系倾角回转误差中一次谐振的分离方法

为更加准确地评定轴系的倾角回转误差,首先推导了轴系倾角回转误差、平面反射镜和自准直仪的安装误差与自准直仪测量数据之间的关系,指出平面反射镜的安装误差在自准直仪的二维读数中为正交一次谐波,然后分析了一次谐振运动误差的形成机理,其在自准直仪的读数中表现为同相一次谐波.针对二维数据中的一次谐波,设计了同相和正交一次谐波的分离方法,扣除了由平面反射镜的安装误差引起的正交一次谐波误差,保留了轴系倾角回转误差中的一次谐振成分,从而改进了轴系倾角回转误差的数据处理方法.最后,通过改变平面反射镜的安装误差,并且对同一轴系的倾角回转误差进行测试,实验结果表明,从两次测试数据中所分离出来的一次谐振误差具有一致性,从而证明了该分离方法的正确性.并且在数据处理过程中只扣除了平面反射镜安装误差引起的正交一次谐波,保留了同相的一次谐振误差项.从最终实验数据可以看出改进后的倾角回转误差数据处理方法更加的合理和精确.

Error separation technology of the first harmonic resonance from the angular rotation errors

To accurately evaluate the wobble error of the rotary axis system, the relationships among the wobble error of the rotary axis system, installation errors of the reflected mirror and of the autocollimator, and the readouts of the autocollimator are established firstly. Installation errors of the reflected mirror are referred to be the first harmonic in the quadrature phase of the autocollimator readouts, and then the formation mechanisms of the first harmonic resonance are analyzed, which is represented as the first harmonic in the same phase. A separation method to handle the first harmonics in the same phase and in the quadrature phase are designed for the first harmonics in the x-and the y-direction readouts of the autocollimator. This method eliminates the first harmonics caused by the installation errors of the reflected mirror, and retains the first harmonic resonance in the rotary error. As a result, the data processing method of the wobble error of the rotary axis system is improved. Finally, by changing the installation errors of the reflected mirror, the wobble errors of the same rotary axis system are measured two times. It is proved that this separation method is correct since the first harmonic resonance errors from the two groups of the measured data are consistent. Meanwhile, it only eliminates the first harmonic caused by the installation errors of the reflected mirror, and retains the first harmonic resonance errors in the rotary errors. The experimental results show that the method of data processing for wobble error of the rotary axis system is more reasonable and accurate.