Research Of The Shock Calibration With Laser-interferometry For High G Accelerometers

In this thesis, the following two aspects of researches are performed about the shock calibration with laser-interferometry for high g accelerometers:First, the criteria about the duration of input acceleration pulses in the accelerometer calibration, and the adjusting of the pulse duration; Second, the study on the arithmetic about decoding the Doppler signals.The aims of this thesis are to establish the criteria about the duration of input acceleration pulses in the accelerometer calibration, to generate the input pulses with ideal durations by changing the dimensions of the Hopkinson bar, and to investigate on modification and decoding the Doppler signals from the interferometer. Having been searched abroad the related documents, the methods such as theoretical analysis,computer simulation,laboratory test are adopted to investigate the issues in question:(1)The criteria about the durations of the input acceleration pulse for the qusia-static and dynamic calibrations are established theoretically from the mathematic model of the accelerometer. And the relations of the duration of the pulses, the resonance frequency and the error of the calibration are presented. Three kinds of Hopkinson bar shock devices have been applied to generate pulses with ideal durations. The available durations of the pulses range from 6.62μs to 210μs.(2)A new method to modify the Doppler signal is applied, with which the phenomena of the zero-line shift and the decrease in amplitude are eliminated. The instantaneous frequency of the Doppler signal can be obtained by derivative of the instantaneous phase of the Doppler signal. The arithmetic about decoding the Doppler signals is proved to possess high accuracy by the artificial Doppler signal.A kind of piezoelectric-type accelerometer 988 developed by 204 institute of the ministry of the weapon industry have been evaluated in the quasi-static calibration with the presented method. And the result of the calibrations entitled this calibration device and the method with validity.