Research On The Frequency Parameter Measurement Of Quartz Reed With Laser Sensor

As the most basic and important component of the quartz accelerometer, quartz reed has been widely used in a variety of inertial navigation fields, such as aircraft, ships, army ground vehicles, tactical missiles, submarines, etc. It's particularly important to detect the machining quality of quartz reed due to its directly affects on the performance of quartz accelerometer. The stiffness parameters are main indexes to characterize the quality of the quartz reed. Thus in this paper, the vibration frequency and the torsional frequency of quartz reed was measured to furthermore calculate the stiffness parameters. Currently, there have been variety of measurement methods available for this purpose, and their measurement principles are different. But as the development of High-tech, people are much more tending to develop new methods with more desirable efficiency and accuracy.The specific outline of the content and work are as follows:Firstly, the measurement principles of various methods to obtain the vibration frequency are analysed. The instantly excited method is selected by comparing the advantages and disadvantages of the various measurement methods. Concerning the characteristics of the vibration signal, together with the principles and characteristics of different spectral estimation methods, the maximum likelihood estimation method based on hybrid nonlinear iteration is adopted. Since the amplitude of the vibration signal and its harmonics are much larger than the torsional signal, the digital filter is designed to separate the vibration signal and the torsional signal, realizing the high precision of the frequency estimation. The four key factors affected the sampled data are analysed in detail, including the position of light spot,the intensity control of the gas source, the time control of the gas source, as well as the placing position of the quartz reed. Thus designing requirements of the corresponding parts are put forward on the basis of the above analysis.Secondly, data-collection algorithm and interactive interface is designed. It can successfully obtain the frequency by intelligent measurement. Through spectral analysis of the displacement sampled data, band-pass filters can be used to separate the vibration frequency and torsional frequency. Chebyshev band-pass filters is designed after comparing the characteristics of a variety of analog filters. Then the filtered data is processed using the maximum likelihood method to estimate the frequencies of these two signals. At the same time, multithread mechanism to is used here to complete loop measurement of the vibration signal.Then the platform of the quartz reed frequency measurement system is constructed.What's more, the impact factors which affect the measurement results is analyzed and the experiment of the quartz reed frequency measurement is also accomplished. The experiment results demonstrated that the measurement repeatability precision of the vibration frequency and the torsional frequency is about 0.01Hz and 0.1Hz, respectively, realized the purpose of high-precision measurement of the quartz reed frequency parameters.