Difference resonant micro accelerometer and driving method thereof

Abstract

The invention relates to a difference resonant micro accelerometer and a driving method thereof, belonging to the technical field of micro mechanical sensors. The mechanical structural layer of the accelerometer comprises two units, wherein each unit comprises a first tuning fork structure and two mass block systems; each mass block system comprises a mass block and two vertical beams; each of the two mass block systems is provided with a vertical beam which is connected with the first tuning fork structure; the two vertical beams construct a second tuning fork structure; and the rigidity of the first tuning fork structure in the axis X direction is lower than the rigidity of the second tuning fork structure in the axis X direction, so that the structural vibration stability is increased, the dependence of sensitivity on manufacturing errors is reduced, and symmetrical errors are restrained. According to the driving method, the two units are adjusted to work in different modes by controlling the voltage loaded on a driving electrode, and difference frequency output is realized through the resonant frequencies of the mass block systems in the same moving direction in the two units, and the difficulty in considering measuring response time and measuring band width in a conventional driving way is overcome.

Description

technical field [0001] The invention relates to a differential resonant micro accelerometer and a driving method thereof, belonging to the technical field of micromechanical sensors. Background technique [0002] Micromachined accelerometers are one of the most successful devices in microelectromechanical systems. They have broad application prospects in the military and civilian fields, and have huge social and economic benefits. Improving performance indicators is currently the research focus in the field of micromachined accelerometers. . The resonant micro-mechanical accelerometer measures the acceleration by detecting the change of the resonant frequency of the mechanical resonator. It is characterized by good stability and high precision. Its outstanding advantage is that it directly outputs the frequency signal, and the transmission process is not easy to be distorted. interface. [0003] At present, silicon micro-resonant accelerometers are mainly based on axial st...

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Problems solved by technology

[0007] The analysis shows that the existing electrostatic stiffness resonant micro-accelerometers have different shortcomings. Under the current silicon micro-machine manufacturing process conditions, it is difficult to achieve fast and wide-bandwidth acceleration measurement

[0008] Electrostatic drive is widely used in micromechanical capacitive sensors. The electrostatic drive of micromechanical resonant accelerometer is carried out in combination with the specific microaccelerometer structure. At present, there is no micromechanical resonant accelerometer that can take into account both measurement response time and measurement bandwidth. There is no driving method that takes both measurement response time and measurement bandwidth into account and is suitable for difference frequency output

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