KR100338802B1 - Tuning fork gyroscope using electrostatic force - Google Patents

Abstract

PURPOSE: A tuning fork gyroscope is provided to allow for mass production and low cost, while achieving improved accuracy of detection of angular velocity. CONSTITUTION: A tuning fork gyroscope comprises a base member(21); a pair of fixed electrode members(22,22') facing each other on the base member with a predetermined gap between the two electrode members; sensing members(27,27') mounted on the base member and spaced apart from the fixed electrode members; an operating plate member(24) interposed between the sensing members and the fixed electrode members and extended into the gap formed between the fixed electrode members; and a support member(26) coaxially connected to the operating plate member, and which supports a detection member(25) extended upward from the sensing member. The operating plate member operates by the electrostatic force generated between the operating plate member and the fixed electrode members.

Description

Tuning Fork Gyroscope with Constant Power

The present invention relates to a gyroscope (Gyroscope) for detecting the inertial angular velocity of an object, and more particularly to the electrostatic force for detecting the angular velocity by signal processing the Coriolis force obtained by the product of the mass and the angular velocity of the mass body. The tuning fork gyroscope used.

In general, the angular velocity sensor has been used as a key component for navigation devices such as missiles, ships, and aircrafts for a long time, and is now gradually applied to the navigation devices of automobiles or the camera shake detection device of high magnification camcorders. The station is on the rise.

However, the angular velocity sensor used for military use in the prior art can achieve precise performance because tens of thousands of parts are made through precision machining and assembly processes, but the manufacturing cost is high, and the bulky structure can be large. There is a disadvantage that it is not easy to apply for general industrial use.

Recently, Japan's Murata has developed a small gyroscope with a piezoelectric element attached to a triangular prism-shaped beam to detect camera shake in camcorders of consumer electronics makers such as Sony and Matsushita. It is used as a sensor. In addition, Tokin Corp. has developed a small gyroscope having an improved cylindrical beam structure to overcome difficulties in manufacturing the gyroscope.

However, the two types of small gyroscopes as described above are made of small parts by precision processing, and thus, there are disadvantages in that manufacturing is difficult and expensive. At the same time, since it is essentially a mechanical component, it has a disadvantage in that it is difficult to develop and develop a circuit.

Meanwhile, in order to improve the disadvantages of gyroscopes as mentioned above, countries have made great efforts to develop more economical, precise and compact gyroscopes by using micro machining technology, which is emerging as a new technology. I'm doing it.

In general, the principle of the angular velocity sensor is a Coriolis force that occurs in a direction orthogonal to two axes when an object that vibrates or rotates constantly in any axial direction receives an angular velocity input in an axis perpendicular to the arbitrary axial direction. It works by detecting Coriolis Force.

1 and 2 show a conventional negative-pair gyroscope and a circuit arrangement of such gyroscopes.

This connects the rectangular piezoelectric elements 12 and 12 'to the predetermined structures 11 and 11' provided in the rotor in the X-axis direction, and rotates them in the X direction of the predetermined structures 11 and 11 '. The angular velocity is detected through the output signal of the piezoelectric element due to the Coriolis force in the Y-axis direction generated when there is an angular velocity w applied to the zero axis in the state of generating the vibration motion. This negative pair gyroscope is also known as a tuning fork type, and has many disadvantages in the fabrication of the structure, and at the same time, the reproducibility is not guaranteed in the process of attaching the piezoelectric element. The piezoelectric element is expensive and the production cost is high. There is an inherent problem of rising mass productivity.

3 and 4 schematically show a conventional cylindrical gyroscope and its circuit arrangement. This cylindrical gyroscope improves the disadvantages of the triangular prism-type gyroscope described above, by making the piezoelectric body 15 into a cylindrical piezoelectric ceramic and forming a plurality of electrodes 16 on the surface thereof. Cylindrical gyroscope having such a structure has the advantage that the manufacturing process is somewhat simple and excellent reproducibility, such as the process of adhering the piezoelectric body (15) can be eliminated, but there is a limit to the manufacture of small and light weight through micro-processing and its cost, In addition, there is a disadvantage that it is difficult to achieve integration with the circuit portion.

The present invention has been created to solve the above problems, it is advantageous to produce a compact and lightweight, and at the same time can obtain a high excitation force using a constant power, it is possible to detect the accurate angular velocity, the tuning fork using a constant power capable of mass production The purpose is to provide a gyroscope.

The present invention to achieve the above object,

With a base member,

At least a pair of fixed electrode members disposed to face each other at predetermined intervals on the base member;

Sensing means provided on the base member to be spaced apart from the fixed electrode member by a predetermined distance;

A seesaw is provided between the detection means and the fixed electrode member to support the movable plate member extending between the fixed electrode members and the detection member coaxially connected to the movable plate member to extend above the detection means. A support member; Equipped,

The movable plate member extends from one side of the support member to extend between the fixed electrode members, and is driven by an electrostatic force with the fixed electrode member.

The detection member is characterized in that it is configured to extend from the other side of the support member to extend above the detection member to cause a change in capacitance with the detection member.

In the present invention, the base member is made of a silicon wafer and the detection member has two elements branched in a horseshoe shape and two sensing means are provided.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The tuning fork gyroscope using the electrostatic force according to the present invention has a pair of fixed electrode members 22 so as to be spaced apart from each other by a predetermined interval on the upper surface of the base member 21 made of a silicon wafer as shown in FIGS. 22 'is provided. Leading portions 22a and 22a 'having a predetermined depth are formed on opposite surfaces of the fixed electrode members 22 and 22'. The fixed electrode members 22 and 22 'and the movable plate member 24 to be described later are connected with driving means 23 and 23' to which a predetermined potential is applied.

The protrusions 24a and 24a 'of the movable plate member 24 are positioned between the fixed electrode members 22 and 22'. The movable plate member 24 is supported in a seesaw form with respect to the base member 21 by a support member together with a detection member described later. Two protruding portions 24a and 24a 'extending in a direction orthogonal to the extending direction of the movable member provided at the distal end of the movable member 24 are provided. Each of these protrusions 24 and 24 'enters the respective leading portions 22a and 22a' of the corresponding fixed electrode members 22 and 22 '.

As described above, the other side of the movable plate member 24 is connected to the detection member 25, and a support member 26 is provided at a connection portion therebetween. The detection member 25 is formed in the shape of a horseshoe having two branches. The detection member 25 extends above two sensing means. The detecting member 25 and the sensing means 27, 27 'induce a change in capacitance while maintaining a predetermined distance. The support member 26 for supporting the detection member 25 and the movable plate member 24 in a seesaw type is maintained at a predetermined height from the base member 21, and the detection member 25 and the movable plate member 24 are supported. Is connected to the upper end thereof and is floating with respect to the base member 21.

Referring to the operation of the tuning fork gyroscope using the electrostatic force according to the present invention configured as described above are as follows.

In the gyroscope rope according to the present invention, when the AC voltage is applied between the movable plate member 24 to the fixed electrode members 22 and 22 'through the driving means 23 and 23', the movable plate member An electrostatic force is generated between the 24 and the fixed electrode members 22 and 22 ', causing the movable plate member 24 to vibrate as shown in FIG. In this state, when the external force makes a rotational movement (angular movement) of the W with respect to the Y axis, the detection members 25 of the two elements separated in the horseshoe shape are moved up and down with respect to the base plate member 21 by the Kooli force. Will move. This movement detects a change in capacitance by the electrostatic electrode, which is the sensing means 27, 27 ', and detects the amount of change (displacement of the detecting member). The amount of change in the detected capacitance is converted into the angular velocity via the signal processor.

The displacement can be obtained as follows.

(S: K; Spring constant of the system. Fx; Constant power in the X direction V _D : Driving voltage)

As described above, the gyroscope according to the present invention has the following effects.

first; Since the base member is manufactured by using micro-processing of the silicon surface, mass production by a batch process is possible, and thus the price can be reduced.

second; The movable plate member has a high excitation force using the electrostatic force, so accurate detection is possible.

third; Quality uniformity is possible.

fourth; By vibrating the movable plate member using the electrostatic force, ultra miniaturization is possible.

As described above, the tuning fork gyroscope using the electrostatic force according to the present invention is manufactured through a relatively simple semiconductor manufacturing process using a silicon wafer, and thus has excellent reproducibility, and also detects the angular velocity from the difference of two capacitances. It is possible to obtain an effect which is hardly affected by vibration and temperature. At the same time, because the ultra-small beam is driven, a large vibration can be obtained with a small constant power, while the beam itself has conductivity, and thus, an application of a driving voltage for obtaining a constant power is easy.

1 is a schematic configuration diagram showing a conventional negative pair type gyroscope,

2 is a schematic circuit diagram of the negative pair gyroscope shown in FIG.

3 is a schematic diagram showing a conventional cylindrical gyroscope,

4 is a schematic circuit diagram of the cylindrical gyroscope shown in FIG.

5 is a plan view of a tuning fork gyroscope using electrostatic force in the present invention,

6 is a view showing the visualized force acting between the fixed electrode member and the movable plate member.

* Explanation of symbols for main parts of the drawings

21; Base member 22; Fixed electrode member

23; Drive means 24; Movable plate member

25; Detection member 26; Support member

Claims (4)

With a base member, At least a pair of fixed electrode members disposed to face each other at predetermined intervals on the base member; Sensing means provided on the base member to be spaced apart from the fixed electrode member by a predetermined distance; A seesaw is provided between the detecting means and the fixed electrode member and supports a movable plate member extending between the fixed electrode members and a detection member connected coaxially with the movable plate member to extend above the detection means. Support member for doing; Equipped, The movable plate member extends from one side of the support member to extend between the fixed electrode members, and is driven by an electrostatic force with the fixed electrode member. And the detecting member extends from the other side of the supporting member to extend above the detecting member to cause a change in capacitance with the detecting member. The method of claim 1, The base member is a tuning fork gyroscope using a constant power, characterized in that formed of a silicon wafer. The method of claim 1, The detecting member has two elements (25) branched into a horseshoe shape, and correspondingly, two sensing means (27, 27 ') are provided. The method of claim 1, Inlet portions facing each other are formed on inner surfaces of the fixed electrode members, The movable plate member is a tuning fork gyroscope using a constant power, characterized in that it comprises a projection for entering both the inlet of the fixed electrode member.