JPH09210690A - Angular velocity detecting sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a rotary angular velocity working in various directions by means of a simplified and inexpensive structure. SOLUTION: A crystal Z board is etched to form a crystal board 4 which has integrally axial piece parts 4-1, 4-2 and 4-3 extending radially with an interval of 120 degrees toward its outer circumferential direction. Exciting parts R1, R2 and R3 and sensor parts S1, S2 and S3 are respectively provided to the tip end parts ST1, ST2 and ST3 of the axial piece parts 4-1, 4-2 and 4-3 of the crystal board 4, so that a rotary angular velocity working around Y1, Y2 and Y3 axial directions is detected by the exciting parts R1, R2 and R3 and the sensor parts S1, S2 and S3 provided on the axial piece parts 4-1, 4-2 and 4-3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity sensor formed by etching a quartz Z plate.

[0002]

2. Description of the Related Art A vibrating element vibrating along a predetermined direction,
For example, a vibrating element vibrating along the X axis in the orthogonal coordinate axis plane (XZ plane) is orthogonal to the XZ plane.
When rotating about the axis, Coriolis force is generated in the Z-axis direction on the vibrating piece due to the angular velocity of rotation. Since the Coriolis force is determined in proportion to the angular velocity, the Coriolis force is indirectly measured as the bending displacement amount of the vibrating element or directly as the strain amount by the piezoelectric effect of the piezoelectric element or the resistance change of the strain gauge. Then, the rotational angular velocity of the vibrating piece acting around the Y-axis direction can be obtained. For this reason, a vibrating vibrating element is mounted on a vehicle, an aircraft or the like as an angular velocity detecting element to record the traveling or flight trajectory of the vibrating element or to detect the yaw rate generated during turning. Further, the angular velocity detecting element is mounted on a robot, and is applied to attitude control and the like.

FIG. 8 shows a conventional "cantilever" using quartz.
It is a figure which shows the principal part of the angular velocity detection sensor of FIG. In the figure, (a) is a plan view, (b) is a view of FIG. 8 (a) viewed from the A direction, (c) is a view of FIG. 8 (a) viewed from the B direction,
8D is a view of FIG. 8A viewed from the C direction. In the figure, 1 is a crystal plate, 2-1 to 2-4 are electrodes for excitation,
3-1 to 3-4 are electrodes for detection, and electrodes 2 for excitation
-1 to 2-4 are on the upper, lower, left and right surfaces of one end 1-1 of the crystal plate 1, and the detection electrodes 3-1 to 3-4 are on the other side of the other end 1-2 of the crystal plate 1. It is provided on the surface. In this figure, the other end 1-2 side of the crystal plate 1 is a base end (fixed end).

In this angular velocity detection sensor, the electrodes 2-1 and 2-3 for excitation are commonly connected to the terminal P1,
Further, the excitation electrodes 2-2 and 2-4 are commonly connected to a terminal P2, and an AC voltage is applied between the terminals P1 and P2. Therefore, at some time, an electric field is generated as indicated by an arrow in FIG. 8B, and then an electric field in the opposite direction is generated, so that one end 1-1 of the crystal plate 1 vibrates left and right. .

Here, the vibration direction of the crystal plate 1 is defined as the X-axis direction,
A direction in the plane of the paper orthogonal to the X-axis direction (longitudinal direction of the crystal plate 1) is a Y-axis direction, and a direction orthogonal to the XY plane (a direction perpendicular to the plate surface of the crystal plate 1) is a Z-axis direction. If yes
When the rotational angular velocity acts around the axial direction, a Coriolis force causes a vibration component in the Z-axis direction. Since the magnitude of this vibration component is proportional to the Coriolis force, a polar charge corresponding to the direction of vibration is generated at the other end 1-2 of the crystal plate 1 in a magnitude proportional to the rotational angular velocity. Thereby, the terminal P3 to which the detection electrodes 3-1 and 3-4 are commonly connected,
A terminal P in which the detection electrodes 3-2 and 3-3 are commonly connected
4, a charge is generated in the direction of the arrow and then in the opposite direction at some time, and a voltage signal corresponding to the Coriolis force is obtained. From the magnitude of this voltage signal, the magnitude of the rotational angular velocity acting around the Y-axis direction can be known. Further, this voltage signal is basically obtained as a sine curve, and by comparing the waveform of this voltage signal and the excitation waveform in phase, the direction of the rotational angular velocity can be known from the advance or delay of the phase.

[0006]

However, such a conventional angular velocity detection sensor can detect only the rotational angular velocity of the quartz plate 1 acting in the Y-axis direction. That is, when the angular velocity detection sensor is mounted on a ship with the Y-axis direction up and down, for example, only the rotational angular velocity acting in the lateral direction can be detected. That is, the rotational angular velocity acting in various directions such as the vertical direction and the diagonal direction cannot be detected. By using a large number of these angular velocity detection sensors, it is possible to detect the rotational angular velocity acting in various directions. However, in this case, a large number of angular velocity detection sensors are required, which increases the cost.

The present invention has been made to solve the above problems, and an object thereof is to detect an angular velocity detecting sensor capable of detecting a rotational angular velocity acting in various directions with a simple and inexpensive structure. To provide.

[0008]

In order to achieve such an object, the first invention (the invention according to claim 1) is to subject a quartz Z plate to an etching process at 120 ° intervals in the outer peripheral direction. A crystal plate integrally having first, second and third shaft piece portions radially extending is formed, and the first and second crystal plates are formed.
And an exciting part and a sensor part are respectively constructed on the third shaft piece part, and the exciting part and the sensor part constructed on the first, second and third shaft piece parts respectively rotate around the extending direction of the shaft piece part. The rotational angular velocity acting on is detected.

A second invention (the invention according to claim 2) is that the Z plate of quartz is etched, and the first, second and third shaft pieces are radially extended at 120 ° intervals in the outer peripheral direction. Is integrally formed, and a crystal plate is formed by bifurcating the tip ends of the first, second and third shaft piece portions, and the first, second and third shaft pieces of the crystal plate are formed. Of the shaft portion by the excitation portion and the sensor portion constructed on the first, second and third shaft piece portions, respectively. The rotational angular velocity acting around the direction is detected.

A third invention (the invention according to claim 3) is a first, second and third invention in which a quartz plate is etched to form a Z plate of quartz and radially extends at intervals of 120 ° in the outer peripheral direction. The first, second, and third shaft piece portions of the crystal plate are integrally formed with an excitation portion, and the excitation portion is formed at the tip end portion, and the sensor portion is formed at the base end portion. With the excitation unit and the sensor unit constructed on the second and third shaft pieces, the rotational angular velocity acting around the extending direction of the shaft piece is detected.

A fourth invention (an invention according to claim 4) is that the first, second and third shaft piece portions are formed by etching a Z plate of quartz crystal and radially extending at intervals of 120 ° in the outer peripheral direction. Is integrally formed, and a crystal plate is formed by bifurcating the tip ends of the first, second and third shaft piece portions, and the first, second and third shaft pieces of the crystal plate are formed. The excitation part and the sensor part are respectively built on one and the other of the two forks of the tip part of the part, and the shaft part part is formed by the excitation part and the sensor part constructed on the first, second and third shaft piece parts. The rotational angular velocity acting around the stretching direction of is detected.

A fifth aspect of the invention (the invention according to claim 5) is that the Z plate of quartz is etched, and the first, second and third shaft piece portions are radially extended at 120 ° intervals in the outer peripheral direction. ,
And a quartz plate integrally having fourth, fifth and sixth shaft piece portions extending in a direction opposite to the extending direction with respect to the first, second and third shaft piece portions. , The excitation part and the sensor part are respectively constructed on the first to sixth shaft piece parts of the crystal plate, and the shaft piece is constructed by the excitation part and the sensor part constructed on the first, second and third shaft piece parts. The rotational angular velocity acting around the stretching direction of the section is detected, and the excitation section and the sensor section built in the fourth, fifth, and sixth shaft piece sections detect the direction perpendicular to the plate surface of the crystal plate. The rotational angular velocity acting around is detected.

Therefore, according to the first to fourth inventions, 1
Rotational angular velocities acting around the extending directions (Y1, Y2, Y3 axis directions) of the first, second and third shaft piece portions radially extending at 20 ° intervals are detected at once by one angular velocity detection sensor. To be done. According to the fifth aspect of the invention, the rotational angular velocity acting about the extending direction (Y1, Y2, Y3 axis direction) of the first, second and third shaft piece portions radially extending at 120 ° intervals, Direction perpendicular to the crystal plate surface (Z-axis direction)
The rotational angular velocity acting around the is detected at once by one angular velocity detection sensor.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail based on embodiments. [Embodiment 1: First Invention, Second Invention] FIG. 1 is a plan view showing a main portion of an angular velocity detection sensor according to an embodiment of the present invention. In the figure, 4 is a quartz plate, and the first shaft piece portion 4 radially extending at 120 ° intervals in the outer peripheral direction thereof.
-1, the second shaft piece portion 4-2, and the third shaft piece portion 4-3 are integrally provided. Shaft piece parts 4-1, 4-2, 4-3
The tip portions ST1, ST2, ST3 of the two are forked. The crystal plate 4 is formed by etching a Z plate of crystal. That is, the plate surface of the crystal plate 4 is the Z plate surface.

Tip portions S of the shaft pieces 4-1, 4-2 and 4-3.
Exciting portions R1 and R are provided on one of the two ends of T1, ST2 and ST3.
2, R3 are constructed, and the sensor parts S1, S2, S are provided on the other side.
3 are built. Excitation unit R (R1, R2, R3)
Shows its tip portion ST (ST1, ST2, ST3) in FIG.
As shown in enlarged form, the electrodes 5-1 to 5-4 for excitation are provided on the upper and lower surfaces and the left and right surfaces of one of the two forks of the tip portion ST, and the electrodes 6-1 to 6-4 for detection are provided on the tip portion. It is provided on the other left and right surfaces of the ST fork. Then, the electrode 5-1 for excitation
And 5-3 are commonly connected to the terminal T1, and the electrodes 5-2 and 5-4 for excitation are commonly connected to the terminal T2. Further, the detection electrodes 6-1 and 6-4 are commonly connected to the terminal T3, and the detection electrodes 6-2 and 6-3 are commonly connected to the terminal T4.

In order to make the quartz crystal bend and vibrate, NT-cu is used.
Although there are t and X-cut (Z plate), NT-cut is difficult to cut out (process) with a double rotation plate.
When manufacturing an angular velocity detecting element, the manufacturing accuracy of the element, especially the geometrical balance greatly influences the characteristics, and therefore it is desirable to process the element by etching using a photolithography method with high processing accuracy. In the etching process, the crystal of quartz has etching anisotropy, and the etching rate in the Z-axis direction is much faster than that of the other axes, so that processing with a high aspect ratio becomes possible. Therefore, in this embodiment, the quartz plate 4 is formed by etching the Z plate of quartz.

Further, a quartz Z plate is used because of the necessity of photolithography, but the quartz crystal is 3.2 crystal,
The X axis is symmetrical with respect to the Z axis three times and is arranged at 120 °. That is, when the crystal rotates once around the Z axis, the X axis has three times at every 120 ° and shows the same characteristics. When the elements are aligned in the axial direction, the etching anisotropy becomes the same and the characteristics become exactly the same, so that it is easy to control the processing and the characteristics. For this reason,
In this embodiment, the shaft pieces 4-1, 4-2, 4-3 are formed at 120 ° intervals to form three angular velocity detecting elements.

In this angular velocity detection sensor, an AC voltage is applied between the terminals T1 and T2 of the excitation units R1, R2 and R3. As a result, an electric field is generated in FIG.
Tip portions ST1, ST of the shaft piece portions 4-1, 4-2, 4-3
One of the two forks of ST2 and ST3 (excitation side) and the other (detection side) are also interlocked to vibrate left and right. Where the tip ST
1, ST2, ST3 vibrating directions are X1, X2, X3 axis directions, and directions in the plane of the paper orthogonal to the X1, X2, X3 axis directions, that is, stretching of the shaft piece portions 4-1, 4-2, 4-3. When the directions are Y1, Y2, Y3 axis directions, Y1, Y2, Y
When the rotational angular velocity acts around the three axes, the Coriolis force generates a vibration component in the Z axis direction.

Due to the bending vibration of this Z-axis direction component,
Electric charges are generated at the two ends of the tip portions ST1, ST2, ST3. This is done by connecting the terminals T3 and T of the sensor units S1, S2 and S3
It is taken out as a voltage signal according to the Coriolis force between 4 and 4. Depending on the magnitude of this voltage signal, Y1, Y2, Y
It is possible to know at once the rotational angular velocities acting around the three axis directions. Also, this voltage signal is basically obtained as a sine curve, and by comparing the waveform of this voltage signal with the excitation waveform in phase, Y1 and Y
It is possible to know the direction of the rotational angular velocity acting around the Y3 axis direction.

Therefore, by using this angular velocity detection sensor, the rotational angular velocity acting in various directions can be detected all at once with a simple and inexpensive structure. If this angular velocity detection sensor is used, the sensor unit S1,
By processing the voltage signals obtained from S2 and S3 by the arithmetic circuit, not only the rotational angular velocity around each axis direction but also the inclination can be measured, and the position of a flying object or an object that moves in three dimensions such as a robot arm can be measured. It is possible to correct an error in the amount of position change due to a tilt component that is a problem during detection, and it is possible to perform highly accurate position detection.

[Second Embodiment: First Invention, Third Invention] In the first embodiment, the tip portions ST1, ST2, ST3 of the shaft piece portions 4-1, 4-2, 4-3 are bifurcated, respectively. The excitation units R1, R2 and R3 were constructed on one of the two forks, and the sensor units S1, S2 and S3 were constructed on the other. On the other hand, in the second embodiment, as shown in FIG.
-Excitation parts R1, R2, R3 are constructed on the front end parts ST1, ST2, ST3 of -2, 4-3, and base end parts BT1, BT2, B
The sensor units S1, S2 and S3 are constructed at T3. By doing so as well, the rotational angular velocities acting around the Y1, Y2, and Y3 axis directions can be detected all at once.

[Third Embodiment: First Invention, Fourth Invention] In the first embodiment, the tip portions ST1, ST2, ST3 of the shaft piece portions 4-1, 4-2, 4-3 are formed into two forks. The excitation units R1, R2 and R3 were constructed on one of the two forks, and the sensor units S1, S2 and S3 were constructed on the other. On the other hand, in the third embodiment, as shown in FIG.
Exciting section R is provided on each of the two forks of T2 and ST3.
1 and S1 are constructed.

That is, for the tip portion ST1, the exciting portion R1 ₁ and the sensor portion S1 ₁ are constructed on _one of the two forks, and the exciting portion R1 ₂ and the sensor portion S1 ₂ are constructed on the other end. Regarding the tip portion ST2, the exciting portion R2 ₁ and the sensor portion S2 ₁ are constructed on _one of the two forks, and the exciting portion R2 is formed on the other end.
2 ₂ and the sensor unit S2 ₂ are constructed. Regarding the tip portion ST3, the exciting portion R3 ₁ and the sensor portion S3 ₁ are constructed on _one of the two forks, and the exciting portion R3 ₂ and the sensor portion S3 ₂ are constructed on the other end. In this case, the excitation units R1 ₁ and R1 ₂ and the sensor units S1 ₁ and S1 ₂ are connected in parallel (see FIG. 5). Similarly, the excitation unit R2
₁ and R2 ₂ , sensor units S2 ₁ and S2 ₂ , excitation units R3 ₁ and R3 ₂ , and sensor units S3 ₁ and S3 ₂ ,
Connect each in parallel.

[Fourth Embodiment: Fifth Invention] First Embodiment
Then, the crystal plate 4 integrally includes a first shaft piece portion 4-1, a second shaft piece portion 4-2, and a third shaft piece portion 4-3 that radially extend at intervals of 120 ° in the outer peripheral direction. To have it.
On the other hand, in the fourth embodiment, as shown in FIG.
In addition to the first shaft piece portion 4-1, the second shaft piece portion 4-2 and the third shaft piece portion 4-3, with respect to the shaft piece portions 4-1, 4-2 and 4-3 The fourth stretched in the direction opposite to the stretching direction
The quartz plate 4 ′ integrally includes the shaft piece portion 4-4, the fifth shaft piece portion 4-5, and the sixth shaft piece portion 4-6. That is, the crystal plate 4 ′ has shaft piece portions 4-1 to 4-6 radially extending at 60 ° intervals in the outer peripheral direction.

The tip portions ST4, ST5, ST6 of the shaft piece portions 4-4, 4-5, 4-6 are bifurcated, and the excitation portions R4, R5, R6 are constructed on one of the bifurcated portions. On the other hand, sensor parts S4, S5 and S6 are constructed. However, in this embodiment, by applying an AC voltage to the exciting portions R4, R5, R6, the tip portions ST4, ST5, ST
One of the two forks of 6 is made to vibrate in the Z-axis direction in conjunction with the other. In addition, the excitation units R4, R5, R6
, The electrodes are attached to the tip portions ST4, ST5, ST.
The sensor portions S4, S are provided on the upper and lower surfaces of one of the two forks.
In S5 and S6, the respective electrodes are connected to the tips ST4 and ST.
5, ST6 are provided on the upper, lower, left and right surfaces of the other of the two forks.

In this angular velocity detection sensor, by applying an AC voltage to the excitation portions R1, R2, R3, the tip portions ST1, ST2 of the shaft piece portions 4-1, 4-2, 4-3 are applied.
The fork of ST3 vibrates in the X1, X2, and X3 axis directions. Here, when the rotational angular velocity acts around the Y1, Y2, and Y3 axis directions, Coriolis force is generated in the Z axis direction. As a result, a voltage signal corresponding to the Coriolis force is obtained from the sensor units S1, S2, S3, and the rotational angular velocity acting around the Y1, Y2, Y3 axis directions can be known at once.

Further, by applying an AC voltage to the exciting portions R4, R5, R6, the shaft piece portions 4-4, 4-5, 4-6.
The forks of the tip portions ST4, ST5, ST6 of the oscillate in the Z-axis direction. Here, when the rotational angular velocity acts around the Z-axis direction, Coriolis force is generated in the X4, X5, and X6 axial directions due to the rotational angular velocity. As a result, the sensor units S4, S
From 5, S6, the voltage signal according to the Coriolis force is obtained,
It is possible to know the rotational angular velocity acting around the Z-axis direction. Note that this element has ST4, S
Although three branches of T5 and ST6 are used, it is possible to measure even one of them as a sensor.

In this embodiment, the shaft piece portion 4-1 is used.
4 to 6 are provided with two forked ends ST1 to ST6,
Although the excitation units R1 to R6 are constructed on one of the two forks and the sensor units S1 to S6 are constructed on the other, the construction method as shown in FIGS. 3 and 4 may be adopted. Further, in this embodiment, in the excitation parts R4, R5, R6, the respective electrodes are arranged on the upper and lower surfaces of one of the two forks of the tip parts ST4, ST5, ST6 as shown in FIG. 7B. , FIG. 7 (a) and FIG.
It may be arranged as shown in (c). In this case, the connection structure is the same, and all vibrate similarly.

[0029]

As is apparent from the above description, according to the present invention, one quartz plate formed by etching a Z plate of quartz is used, and in the first to fourth inventions, 120
The rotational angular velocities acting around the extending directions (Y1, Y2, Y3 axis directions) of the first, second, and third shaft piece portions radially extending at intervals of ° can be detected all at once. Then, the rotational angular velocity acting around the extending direction (Y1, Y2, Y3 axis direction) of the first, second and third shaft piece portions radially extending at intervals of 120 °, and the vertical direction to the plate surface of the quartz plate. The rotational angular velocities acting around various directions (Z-axis direction) can be detected all at once, and the rotational angular velocities acting in various directions can be detected with a simple and inexpensive structure.

[Brief description of drawings]

FIG. 1 is a plan view showing a main part of an angular velocity detection sensor according to an embodiment of the present invention.

FIG. 2 is an enlarged view showing a tip portion of a shaft piece portion of the angular velocity detection sensor.

FIG. 3 is a plan view showing a main part of another embodiment (second embodiment) of this angular velocity detection sensor.

FIG. 4 is a plan view showing a main part of another embodiment (Embodiment 3) of this angular velocity detection sensor.

5 is a diagram showing a parallel connection state of each of the excitation units R1 ₁ and R1 ₂ and the sensor units S1 ₁ and S1 ₂ in FIG.

FIG. 6 is a plan view showing a main part of another embodiment (fourth embodiment) of this angular velocity detection sensor.

FIG. 7 is a diagram showing an arrangement example of electrodes in excitation units R4, R5, and R6 in FIG.

FIG. 8 is a diagram showing a main part of a conventional “cantilevered” angular velocity detection sensor.

[Explanation of symbols]

4, 4 '... Crystal plate, 4-1 to 4-6 ... Shaft piece part, ST (S
T1 to ST6) ... Tip part, BT (BT1 to BT3) ... Base part, R (R1 to R6) ... Excitation part, S (S1 to S6) ...
Sensor part, 5-1 to 5-4 ... Electrodes for excitation, 6-1 to 6
-4 ... Electrode for detection.

Claims (5)

[Claims] 1. A quartz plate integrally formed with first, second and third shaft piece portions formed by etching a quartz Z plate and radially extending at intervals of 120 ° in the outer peripheral direction thereof. An excitation part and a sensor part respectively constructed on the first, second and third shaft piece parts of the crystal plate, and an excitation part constructed on the first, second and third shaft piece parts, and An angular velocity detection sensor, wherein the sensor unit detects a rotational angular velocity acting around the extending direction of the shaft piece. 2. A quartz Z plate is formed by etching and integrally has first, second and third shaft piece portions radially extending at 120 ° intervals in the outer peripheral direction. 1, a quartz plate with the tip of each of the second and third shaft pieces being bifurcated, and one of the two forks of the tip of the first, second, and third shaft piece of this quartz plate A built-in excitation part and a sensor part built in the other are provided, and by the excitation part and the sensor part built in the first, second and third shaft piece parts, the rotation in the extending direction of the shaft piece part is achieved. An angular velocity detection sensor, which detects a rotational angular velocity that acts on a. 3. A quartz plate which is formed by etching a Z plate of quartz and integrally has first, second and third shaft piece portions radially extending at 120 ° intervals in the outer peripheral direction thereof, The first, second and third shaft parts of the crystal plate are provided with an exciting part built at the tip end part and a sensor part built at the base end part of the first, second and third shaft part parts. An angular velocity detection sensor, characterized in that an excitation unit and a sensor unit constructed in one unit detect a rotational angular velocity acting around the extending direction of the shaft unit. 4. A quartz Z plate is formed by etching and integrally has first, second and third shaft piece portions radially extending at 120 ° intervals in the outer peripheral direction. 1, a crystal plate in which the tips of the second and third shaft pieces are bifurcated, and one of the two forks of the tip of the first, second, and third shaft pieces of the crystal plate, and On the other hand, an exciting part and a sensor part each built are provided, and the exciting part and the sensor part built in the first, second, and third shaft piece parts are used to extend around the extending direction of the shaft piece part. An angular velocity detection sensor, which detects an acting rotational angular velocity. 5. A first, second and third shaft piece portions formed by etching a quartz Z plate and radially extending at intervals of 120 ° in the outer peripheral direction, and the first, second and third shaft piece portions. A crystal plate integrally having fourth, fifth and sixth shaft piece portions extending in a direction opposite to the extending direction with respect to the third shaft piece portion, and first to sixth crystal plates of the crystal plate. Of the shaft piece portion, the excitation portion and the sensor portion are respectively constructed, and by the excitation portion and the sensor portion built in the first, second and third shaft piece portions, Rotation that acts around a direction perpendicular to the plate surface of the quartz plate by detecting the rotational angular velocity that acts around, and by the excitation unit and the sensor unit that are constructed on the fourth, fifth, and sixth shaft pieces. An angular velocity detection sensor characterized by detecting an angular velocity.