Micromachined Open Airflow Z-Axis Angular Velocity Sensor

Abstract

The invention relates to a micromechanical open air flow type Z-axis angular velocity sensor which comprises an open Z-axis angular velocity chip, a PCB (printed circuit board), a base, a housing, a buffered silica gel sheet and leads, wherein the open Z-axis angular velocity chip comprises an upper cover board, an upper silicon board, a lower silicon board and a bottom board; a layered structure of the angular velocity chip forms an open air flow network structure; an air flow network comprises a pump cavity below a piezoelectric ceramic vibrator, inlet chambers and an outlet sensitive chamber; the cross-sectional area of a guide hole of the upper silicon board is greater than that of a cavity orifice of the pump cavity, but less than that of a confluence opening; a piezoelectric pump driving circuit of the PCB supplies excitation voltage to the piezoelectric ceramic vibrator on the upper cover board; a pair of long parallel hot lines is arranged on the surface of the lower silicon board in the outlet sensitive chamber as two arms of a Wheatstone bridge in the PCB. The hot lines in the outlet sensitive chamber are longer, the resistance is large, the angular velocity output voltage is high under the condition of the same hot line current is supplied, and the sensor is high in sensitivity and practicability.

Description

technical field [0001] The invention belongs to the technical field of measuring the angular velocity and posture of a moving body by using the principle of Coriolis force, in particular to the technical field of a micro airflow angular velocity sensor produced by combining high-precision laser cutting and micro-mechanical technology. Stabilization systems for micro-carriers such as drones, wearable devices, helmets, smart robots, cameras, etc. Background technique [0002] In the prior art, there are generally vibration beams and suspension devices in the sensitive element of the micro angular velocity sensor represented by the micromechanical vibration gyroscope, which will cause damage due to excessive inertial force during large impact or strong vibration, so the impact resistance is weak; Its structure and manufacturing process are complicated, and the sensitive components are not easy to drive, resulting in weak output signal of the sensor. The jet angular velocity se...

AI Technical Summary

Problems solved by technology

The high-sensitivity piezoelectric jet angular velocity sensor proposed in Chinese patent 89105999.7 is composed of a housing of a sensitive device, a nozzle body, a sensitive element, a piezoelectric pump, a pump seat, a disc spring, a lock nut, an external circuit system, and a mechanical system. The sensitive element of a one-dimensional angular velocity sensor is made of copper, aluminum or stainless steel and other materials by traditional machining. The sensitive element is large in size and high in power, and cannot be used in the field of micro-carrier attitude measurement and control. It is difficult to ensure the parallelism and perpendicularity of the hot wires, so the cross-coupling is large, the consistency is poor, it is difficult to mass produce, and the cost is high

In the prior art, MEMS technology is used to etch the gas flow network in a silicon chip. The size of the gas flow network is usually less than half of the thickness of the silicon chip. Since the thickness of the silicon chip is only about 300 μm, the gas capacity of the gas flow network is small. At the same angular velocity input The inertia it receives is small, the deflection of the airflow beam is small, and the sensitivity of the angular velocity sensor is very small; in addition, due to the lack of design, the airflow network is made along the surface of the silicon wafer, in order to ensure that the deformation direction (vibration direction) of the piezoelectric pump vibrator is consistent with the The length and direction of the airflow network are consistent. The piezoelectric pump driving the gas flow is generally installed at the silicon wafer section perpendicular to the silicon wafer surface. The effective deformation area of ​​the piezoelectric pump vibrator corresponds to the cross-sectional area of ​​the airflow network, which is usually smaller than that of the silicon wafer. Cross-sectional area, due to the large difference between the cross-sectional area and the surface area of ​​the silicon wafer, the size of the corresponding piezoelectric pump vibrator is generally less than 1mm×1mm, so its ability to drive gas flow is very weak, and the sensitivity of the angular velocity sensor is low. It is difficult to achieve bonding in the actual process, and it cannot be practical and mass-produced

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