随机角振动激励下的陀螺仪动态特性校准方法

Calibration method for dynamic features of gyroscopes under random angular vibration excitation

对陀螺仪动态特性的校准,目前皆采用正弦激励校准法,但该方法与陀螺仪实际工况差别较大且需逐个频点校准。为解决正弦法效率低下的问题,对随机激励下的校准方法进行了研究。为实现随机法校准,首先对标准角振动台的圆光栅信号进行解算,得到标准随机角振动信号,并将其与被校陀螺仪的输出信号同时进行抗混叠滤波处理;继而用加窗与重叠的方式计算滤波后两个信号的自谱与互谱,并在此基础上使用H_(v)法辨识出被校陀螺仪的频响函数(FRF),从而实现随机法校准。对比正弦法校准,两者灵敏度差值小于1%,相位差小于1°,校准结果基本一致。由于随机法更接近陀螺仪的实际工况,并可一次性校准陀螺仪宽频段内的动态特性,因此随机激励法可以作为一种替代正弦法的校准方法。

Currently,sinusoidal excitation calibration method is adopted to calibrate the dynamic features of gyroscope,however,which does not exactly conform to the actual working conditions of gyroscope and needs to be calibrated at each frequency point.As a result,the calibration method under random excitation is studied to solve the problem of low efficiency of sinusoidal method.In order to achieve the random calibration,firstly,the circular grating signal of standard angular vibration table is analyzed and calculated to obtain the standard signal of random angular vibration,which is then processed simultaneously with the output signal of the calibrated gyroscope by the anti aliasing filter.Then,the auto-power spectrum density and cross-power spectrum density of the two filtered signals are calculated by windowing and overlapping,and on this basis,the Hv method is used to identify the frequency response function(FRF)of the calibrated gyroscope to eventually achieve the random method calibration.By comparison,the sensitivity difference between sinusoidal calibration and random calibration is less than 1%,and the phase difference is less than 1°.The calibration results are basically the same.Given the fact that the random calibration method is more in line with the actual working condition of the gyroscope and can calibrate the dynamic features of the gyroscope in a wide frequency band at one time,the calibration method under random excitation can be used as an alternative to the sinusoidal method.