A Micromachined Accelerometer with Adjustable Low Stiffness

Abstract

The invention discloses an adjustable low-rigidity micro-mechanical accelerometer, which belongs to the technical field of acceleration measurement and comprises an acceleration sensitive module, a tuning module, a displacement detection module and a force feedback module. The mass block in the acceleration sensitive module is connected to the anchor area of ​​the substrate through the buckling elastic beam. During the processing process, the buckling elastic beam is deformed by the internal stress, and the mass block breaks through the constraint boundary of the self-locking structure to realize self-locking. After self-locking, it is super flexible. working area. The open-loop stiffness of the accelerometer is adjustable by using the comb-tooth capacitance and the triangular grid capacitance tuning design. The accelerometer can work in the open-loop and closed-loop working modes. In the open-loop working mode, the displacement detection module detects the capacitance change caused by the displacement of the mass block and then detects the change of the external acceleration, and can further use the gate capacitance of the force feedback module to complete Closed-loop control. The invention has simple structure and high sensitivity, and can be applied to weak acceleration signal detection.

Description

technical field [0001] The invention belongs to the technical field of acceleration measurement, and more particularly relates to a micro-mechanical accelerometer with adjustable stiffness. Background technique [0002] Low-stiffness micro-machined accelerometers are widely used in space measurement, underground resource exploration and other occasions. By utilizing the low-stiffness characteristics of elastic beams, micro-machined accelerometers with high sensitivity can be realized. At present, there are two main types of elastic beams for low-stiffness accelerometers: one is a geometric anti-spring beam, and the other is a positive-negative mixed beam. [0003] The geometric anti-spring beam (geometric anti-spring) includes three asymmetric elastic beams, which use the coupling effect on the two degrees of freedom to realize the stiffness change in the sensitive direction. During the movement, the stiffness first decreases and then increases . Positive and negative hybr...

AI Technical Summary

Problems solved by technology

Both elastic beam structures are suitable for gravimeters or micromachined accelerometers, but it is difficult to ensure that the working range of the elastic beam is always at the low stiffness position of the elastic beam, and there are also minimum acceleration input thresholds, stiffness cannot be adjusted, and the scale factor is not linear It is difficult to satisfy the application in various low-stiffness micro-mechanical static or resonator structures

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