Weakly coupled MEMS resonance type accelerometer based on mode localization effect

Abstract

The invention discloses a weakly coupled MEMS resonance type accelerometer based on a mode localization effect, and belongs to the field of MEMSs. The accelerometer comprises two movable mass blocks and two single beam resonance systems, wherein the two movable mass blocks are the same completely, and the two single beam resonance systems are connected together via a mechanical coupling beam. According to the weakly coupled MEMS resonance type accelerometer disclosed by the invention, a design of single resonance beams is used, so the mode interference is greatly reduced; a capacitor plate is designed at an inside and an outside of each of the resonance beams, so the differential detection for amplitudes of the single resonance beams can be realized, not only can the intensity of a signal be enhanced, but also the feedthrough capacitance signal interference due to a potential difference between a drive electrode and a detection electrode is eliminated, and the stability and the accuracy of a measurement signal can be greatly improved; as a stiffness adjustment electrode is increased, the flexible selection for a working point and the adjustment for a linearity working range are realized; and by placing an alternating current drive electrode in the middle of the two resonance beams, the frequency components of an output signal are more single, and the detection for the output signal and the design for a closed loop control circuit are enabled to be easier.

Description

[0001] Field: [0002] The invention relates to an accelerometer, in particular to a miniature resonant accelerometer based on the mode localization principle, which belongs to the field of micro-electromechanical systems (MEMS). [0003] Background technique: [0004] The accelerometer is an instrument used to measure the acceleration of the carrier. It is the basic core component of the inertial navigation system. It has important application value in aerospace, automotive industry, consumer electronics, construction machinery and other fields. With its many advantages such as small size, light weight, low cost and easy mass production, MEMS accelerometer has become the main development direction of accelerometer. At present, the working principle of most MEMS accelerometers is based on Newton's second law, which uses a movable mass to generate inertial force, and converts the inertial force into voltage, current or frequency through electrostatic, piezoresistive, piezoelectr...

AI Technical Summary

Problems solved by technology

However, the accelerometer still has many problems in terms of structure design, drive detection circuit design, etc. The interference of the feedthrough capacitor signal greatly reduces the effective signal amplitude; the weakly coupled resonator of the accelerometer is composed of a DETF (double-ended fixed tuning fork) structure, and is driven from both ends of the resonator at the same time. The resonator structure has four operating modes, which brings great difficulties to the selection of operating modes and the design of the closed-loop circuit; due to the structural mismatch caused by the processing error to the two weakly coupled resonators, the accelerometer The initial working point cannot be determined, and it is difficult to flexibly adjust the working point and linear measurement range

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