Micromechanical accelerometer and calibration compensation method thereof

Abstract

The invention discloses a micromechanical accelerometer and a calibration compensation method thereof, and belongs to the technical field of acceleration measurement. The equivalent stiffness of the accelerometer can be adjusted by applying bias tuning voltage to a bilateral parallel plate type comb capacitor, and the accelerometer can also work in a position closed-loop state due to the fact that the electrostatic stiffness of the comb capacitor changes along with displacement. The closed-loop reference position calibration comprises the steps: introducing a bandwidth external calibration signal on the tuning voltage, demodulating and filtering the displacement equivalent voltage to obtain a displacement disturbance quantity, and compensating the reference position through a feedback loop based on the displacement disturbance quantity until the displacement disturbance quantity is reduced to zero; and the equivalent stiffness calibration comprises the steps that: an in-bandwidth calibration signal is added to a closed-loop reference position, demodulation filtering is carried out on a force balance feedback control signal, a voltage signal representing the equivalent stiffness of the accelerometer is obtained, and a stiffness compensation closed loop is established based on the voltage signal, so that the equivalent stiffness of the accelerometer can be kept constant. According to the invention, the output drift of the accelerometer can be detected and suppressed favourably.

Description

technical field [0001] The invention belongs to the technical field of acceleration measurement, and more specifically relates to a micromechanical accelerometer and a calibration compensation method thereof. Background technique [0002] Through electrostatic trimming technology, the equivalent stiffness of the micromachined accelerometer can be reduced, and the range and sensitivity of the micromachined accelerometer can be changed. Trimming and closed-loop control status. The asymmetric comb capacitor is an electrostatic trimming design commonly used in the MEMS field, which can be used to reduce the equivalent stiffness of the micromachined accelerometer or gyroscope to achieve stiffness trimming; the pull-in voltage of the asymmetric comb capacitor and pull-in time can also be used for acceleration measurements. However, the use of asymmetric comb capacitors will change the center position of the accelerometer and introduce asymmetry problems. On the other hand, micr...

AI Technical Summary

Problems solved by technology

However, the use of asymmetric comb capacitors will change the center position of the accelerometer and introduce asymmetry problems

On the other hand, micromachined accelerometers are affected by temperature and produce drift effects, which is one of the key issues restricting the accuracy of acceleration measurement

At present, most of the methods to actively suppress the output drift of the micromachined accelerometer rely on temperature sensors, but at the same time increase the complexity of the micromachined accelerometer system

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