MEMS gyroscope online frequency difference identification method based on noise power spectrum estimation

Abstract

The invention discloses an MEMS gyroscope online frequency difference identification method based on noise power spectrum estimation. The method comprises the steps of determining a power spectrum theoretical curve of the gyroscope harmonic oscillator mechanical thermal noise at the output end of a detection mode according to the Q value of the detection mode and a preset resonant frequency; performing voltage sampling and Fourier transform analysis on the detection mode in a normal working state of a gyroscope to obtain a power spectrum curve of an output end signal; performing cross-correlation operation on the power spectrum theoretical curve and the power spectrum curve of the output end signal to obtain a cross-correlation result curve, and determining the hysteresis quantities corresponding to two peak values in a cross-correlation analysis result; determining the resonant frequency of the detection mode by using the obtained lag value and the known gyroscope driving mode resonant frequency; and calculating to obtain the frequency difference of the working mode of the gyroscope. According to the present invention, on the premise that the normal working state of the MEMS gyroscope is not affected, the modal frequency information is extracted on line in real time from the mechanical thermal noise inevitably existing in a harmonic oscillator, and the modal frequency difference recognition is achieved.

Description

technical field [0001] The invention relates to the technical field of MEMS gyroscopes, in particular to an online frequency difference identification method for MEMS gyroscopes based on noise power spectrum estimation. Background technique [0002] In recent decades, with the rapid development of micro-electromechanical systems (MEMS) technology and the continuous maturity of micro-machining technology, MEMS gyroscopes have emerged as the times require. Compared with traditional gyroscopes, MEMS gyroscopes have small size, high reliability, and low cost. Therefore, it is widely used in various fields such as automotive unmanned driving, aerospace, navigation and guidance, and has a very wide range of applications. In practical applications, the working modes of MEMS gyroscopes are divided into modal matching mode and modal mismatching mode. The mechanical sensitivity of the gyroscope in the modal matching state is much greater than that of the gyroscope in the modal mismatc...

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Problems solved by technology

In order to better realize the real-time matching of gyroscope modes, the key is to identify the frequency difference of the modes. The existing mode identification methods are mainly divided into two categories: one is offline calibration, which is calculated and fitted by measuring data, Although this method is simple and feasible, it has poor real-time performance and high requirements for repeatability; the other method is the traditional online real-time measurement, which requires disturbance input to a certain mode or channel of the gyroscope. Although this method realizes online real-time measurement, but it will affect the normal working state of the gyroscope

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