Control method and device for micromechanical accelerometer

Abstract

The invention discloses a control method and device for a micromechanical accelerometer. The method is suitable for a micromechanical accelerometer provided with a driving electrode structure and tuning structures. According to the control method and device of the invention, cosine injection modulation signals of a certain frequency are applied to the driving electrode of the micromechanical accelerometer; a fixed tuning voltage is applied to the nonlinear tuning structure of the micromechanical accelerometer; one path of the output signals of the micromechanical accelerometer which have passed through a high-frequency carrier modulation and demodulation module pass through a frequency self-regulating module, so that tuning control signals can be obtained and are applied to the linear tuning structure of the micromechanical accelerometer; the other path of the output signals of the micromechanical accelerometer which have passed through the high-frequency carrier modulation and demodulation module pass through an acceleration closed-loop measurement module, so that the magnitude of an externally inputted acceleration is obtained, and closed-loop feedback control signals are formed;and the formed closed-loop feedback control signals and the cosine injection modulation signals of a certain frequency together act on the driving electrode. With the control method and device of theinvention adopted, the magnitude of the resonance frequency of the micromechanical accelerometer can be arbitrarily controlled, acceleration measurement is not affected, and the stability and precision of the micromechanical accelerometer can be effectively improved.

Description

technical field [0001] The invention relates to a micromechanical accelerometer, in particular to a control method and device for a micromechanical accelerometer. Background technique [0002] Micromachined accelerometer is an inertial sensor based on silicon micromachining technology for measuring acceleration information. It has the advantages of low power consumption and compatibility with integrated circuits, and has been widely used in civilian fields. Especially in the military field, high-precision micro-mechanical accelerometers can accurately provide information such as acceleration and speed of missiles and rockets to meet the requirements of navigation and guidance control. [0003] A high-precision micromachined accelerometer can usually be achieved by increasing the sensitivity of the micromachined accelerometer, which requires the micromachined accelerometer's elastic coefficient or resonant operating frequency to be very low. This can be achieved by significa...

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Problems solved by technology

[0004] However, these high-precision micromachined accelerometers can only reach a very low resonance frequency in theory, and it is difficult to achieve the expected high-precision performance in actual processing and use. This is mainly limited by the following reasons: 1) actual processing There are certain processing errors and defects in the manufacturing process, and it is difficult to make elastic beams with smaller beam widths and low elastic coefficients. This is unavoidable; 2) The use of micro-mechanical accelerometers is a temperature range with a large temperature difference between positive and negative. This will cause a significant change in the Young's modulus of the silicon material, thereby changing the elastic coefficient of the mechanical structure and shifting the original resonant frequency of the micromachined accelerometer

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