某经纬仪方位谐振频率分析

Harmonic frequency analysis for the azimuthal component of a large-sized itometer

谐振频率是光电经纬仪的一个重要指标,直接影响着经纬仪的动态特性和跟踪精度。工程上对光电经纬仪进行谐振频率估算时,一般采用霍尔兹法。但实际上由于光电经纬仪结构十分复杂,很难精确地计算其等效惯量与刚度,即使算出来其结果的误差也很大。本文针对某经纬仪的垂直轴系进行结构简化,建立了方位谐振频率分析的弹簧力学模型,通过有限元分析计算了在等效支承条件下的前几阶固有频率和振型图。计算结果与伺服系统正弦激振测试结果基本一致。

The harmonic frequency is an important parameter in the large-sized photoelectric altometer,which is related with the dynamic performance and the tracking precision of the altometer.In engineering,the Holz Law is generally used to estimate the harmonic frequency for the large-sized photoelectric altometer.However,the structure of the altometer is actually too complicated to calculate the equivalent inertia and rigidity precisely,and the estimated results have a large amount of error.In this paper the structure of the azimuthal shafting has been simplified and the spring-damp mechanical model construct for the harmonic frequency analysis.Then we have got the natural frequencies of the fore several steps and graphics of the modal based on FEA,and the results have a good agree with the testing data from the sinusoidal shock excitation in the servosystem.