An Adaptive Closed-loop Measurement System of Resonant Accelerometer

Abstract

The invention discloses a self-adaptive closed-loop measuring system of a resonant accelerometer, the frequency control adopts a self-adaptive control phase-locked loop structure, and the control modeof a loop filter can be automatically selected according to the change of the external acceleration, the problems that in the prior art, circuit parameters are fixed, and self-adaptive adjustment cannot be achieved are solved, and the contradiction between the response speed and the steady-state phase difference of the phase-locked loop is effectively overcome, so that the measuring range, the scale factor linearity and the zero bias stability of the accelerometer are effectively improved. Meanwhile, the structure is simple, a complex algorithm is not needed, and the system has the advantagesof being simple, efficient and high in adaptability. A PI control unit adopts an incremental algorithm, the improvement of a traditional position type PI algorithm is achieved, a better control effect can be obtained, and the stability of the system is improved; an amplitude control module adopts an alternating current automatic gain control method, a simple and effective amplitude demodulation method is adopted in the module, hardware resources are saved, and the amplitude of the driving signals can be adjusted within a large range.

Description

technical field [0001] The invention belongs to the technical field of MEMS accelerometers, and relates to a signal detection and drive control system design method of the accelerometer, in particular to a closed-loop measurement technology of the MEMS silicon microresonance accelerometer. Background technique [0002] Silicon microresonant accelerometers have the advantages of small size, low power consumption, quasi-digital output, and great potential for accuracy improvement. They have good application prospects and have become a research hotspot in the field of inertial research at home and abroad in recent years. The frequency control of existing resonant accelerometers mostly adopts the form of phase-locked loop, and the loop filter is mostly based on PI control. However, due to the fixed PI parameters, the contradiction between bandwidth and response speed cannot be solved, which limits the range of the accelerometer. , bias stability, scale factor linearity and other...

AI Technical Summary

Problems solved by technology

The frequency control of existing resonant accelerometers mostly adopts the form of phase-locked loop, and the loop filter is mostly based on PI control. However, due to the fixed PI parameters, the contradiction between bandwidth and response speed cannot be solved, which limits the range of the accelerometer. , bias stability, scale factor linearity and other indicators

[0003] Some literatures propose methods such as fuzzy PID control and neural network PID control to adjust PI parameters online, but the algorithm is too complicated, which will reduce the reliability of the system and greatly occupy hardware resources.

At the same time, the signal amplitude demodulation module of the existing resonant accelerometer mostly adopts rectification filtering, peak detection and other methods, which will occupy more hardware resources

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