Research And Application Of MEMS Gyroscope Driving Algorithm

The analog drive circuit of the MEMS gyroscope is easily affected by the external environment,which leads to a decrease in the accuracy and stability of the gyroscope.In response to this problem,the digital drive circuit has become a more efficient drive solution.Compared with analog circuits,digital circuits are more integrated and have stronger anti-interference performance.Therefore,the use of digital drive circuits will further improve the anti-interference performance of the drive circuit and can further reduce the area of the drive circuit and improve the integration of the system.The main purpose of this article is to use programmable logic devices to implement digital drive algorithms in MEMS gyroscope drive circuits instead of analog drive circuits.The driving algorithm is mainly composed of a frequency tracking system and an amplitude stabilization system.These two systems use a digital phase-locked loop algorithm and an automatic gain control algorithm respectively.The main research contents are as follows:(1)Build an analog drive circuit model of the MEMS gyroscope,and preliminarily draw up the range of internal parameters of the gyro drive circuit based on the analog drive circuit model.After that,write a program to perform floating-point simulation to determine the actual physical parameter values of each module in the drive loop.(2)Perform digital analysis on each physical module in the drive circuit,and build a corresponding digital model.In order to further improve the signal quality in the frequency tracking system,a low-pass filter is added to the frequency tracking loop to filter out high-frequency signals.Then use hardware language to describe the driving algorithm and perform fixed-point simulation.After a large number of fixed-point simulations,the amount of memory required for each parameter in the drive loop was determined for specific implementation,and the performance of the digital drive loop was further verified.(3)Test the frequency tracking performance and amplitude stability of the digital drive loop on the hardware.The experimental results show that the drive circuit can achieve the purpose of frequency tracking and stable amplitude.The final measurement of the scale factor of the gyro is 13lsb/°/s,and the bias stability is 9.028°/hr.