JP2686209B2 - Vibrating gyro - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

This invention relates to a pair of piezoelectric elements,
The present invention relates to a vibrating gyroscope that can always perform stable self-excited vibration and detection by exerting functions of driving, feedback, and detection.

[0002]

2. Description of the Related Art As a conventional vibrating gyroscope, for example,
The ones shown in block diagrams in FIGS. 5 and 6 are known. Here, in the vibrating gyroscope shown in FIG. 5, the driving piezoelectric element 52 is attached to one side surface of the vibrating body 51 having a quadrangular cross section, and the feedback piezoelectric element 52 is provided on the side surface opposite to the side surface. The element 53 is attached, and on the other two side surfaces orthogonal to these, the respective piezoelectric detection elements 54,
The vibrator 56 is configured by attaching 55,
By supplying the output from the driving device 57 to the driving piezoelectric element 52 and returning the output of the feedback piezoelectric element 53 to the driving device 57, the vibrator 56 moves in the X-axis direction of the orthogonal three-dimensional coordinate system. A predetermined self-excited vibration is performed. Then, under the self-excited vibration, when the oscillator 56 is rotated around the Z axis, the oscillator 56 generates Y due to the Coriolis force.
Axial vibration is induced, and a voltage associated with this Y-axis vibration is generated in each of the detecting piezoelectric elements 54 and 55. Therefore, these voltages are applied to the differential amplifier 58, the synchronous detector 59 and the DC amplifier. By sequentially passing through 50, the angular velocity of the oscillator 56 is obtained as a DC output.

Further, in the vibrating gyro shown in FIG. 6, driving piezoelectric elements 71 and 72 are attached to each of two side surfaces of a vibrating body 61 having a triangular cross section, and the other side surface is used for returning. The piezoelectric element 63 is attached, and the output from the driving device 67 is applied to the driving piezoelectric element 7 via the resistors 73 and 74, respectively.
The oscillator 66 is configured to be self-oscillated in the X-axis direction by supplying the output to the drive device 67 by supplying the output from the return piezoelectric element 63 to the drive device 67. Here, the oscillator 66 is rotated around the Z axis by differentially amplifying the voltage generated in each of the driving piezoelectric elements 71 and 72 that also serve as the detecting piezoelectric element, performing synchronous detection, and then performing DC amplification. It is possible to detect the Coriolis force in the Y-axis direction, which is generated by the above, and thus the angular velocity.

By the way, in the vibration gyro shown in FIG. 5, since the respective piezoelectric elements 52, 53, 54, 55 are adhered to the vibrating body 51 by an epoxy resin or other adhesive, the ambient temperature The strength of the adhesive caused by the change of, the elastic properties and other changes, for example, the characteristic difference between the driving piezoelectric element 52 and the feedback piezoelectric element 53 is changed, the vibration conditions fluctuate, This causes a problem that the self-excited vibration of the vibrator 56 becomes unstable. Also, when a temperature cycle is applied, the adhesive properties will change over time.
There are also problems caused hysteresis varying to driving conditions, further, there is a problem in that the change in adhesive strength of the detecting piezoelectric elements 54, 55 also causes drift.

Further, due to variations in the characteristics of the piezoelectric elements 52, 53, 54, 55 and the asymmetry of the sectional shape of the vibrating body 51,
Ideally, vibration in the Y-axis direction that does not occur when the vibrator 56 does not rotate actually occurs and causes a so-called leakage voltage. However, there is a problem in that the magnitude of the leakage voltage also changes depending on the driving voltage and other driving conditions and causes drift. Further, in the case of this conventional technique, there is a problem that the assembling work of the vibrator 56 is extremely troublesome because each piezoelectric element needs to be bonded to each side surface of the vibrating body 51 with high accuracy.

In the prior art shown in FIG. 6, since the driving piezoelectric elements 71, 72 are also used as the detecting piezoelectric elements, the change in leakage voltage due to the change in adhesive is shown in FIG. It can be less than that of technology. However, also in this conventional technique, the feedback piezoelectric element 63 is separately provided as in the case shown in FIG.
Regarding the vibration condition, the same problem as described above remains.

[0007]

The present inventor once found that
In order to advantageously solve the above-mentioned problems that the above-mentioned conventional technology has, the work of assembling the vibrator is facilitated and the fluctuation of the driving condition due to the influence of the adhesive is effectively reduced, and the change of the leakage voltage is sufficiently suppressed. We proposed a vibration gyro that can be suppressed small (Japanese Patent Application No. 3-162330).

This vibrating gyro, previously proposed by the present inventor, is as shown in the block diagram of FIG. In the vibrating gyro shown in FIG. 4, one piezoelectric element 2 is attached to one side surface of the vibrating body 1 having a quadrangular cross-sectional shape, and the electrodes of the piezoelectric element 2 are arranged in the width direction of the vibrating body 1. The vibrator 3 is configured by dividing the electrodes into the divided electrodes 2a and 2b.

Further, here, the drive unit 4 is connected to the respective divided electrodes 2a and 2b via the impedance elements Z ₆ and Z ₇ , and also to the capacitive element 5 via the other impedance element Z _8. By connecting them, an AC voltage from the driving device 4 can be simultaneously applied to each of them.

On the other hand, each of the impedance elements Z ₆ , Z
₇ and connecting portions 6, 7 between the respective divided electrodes 2a, 2b
Is connected to the differential amplifier 9 via the adder 8 and the adder 8
Then, the outputs from both the connecting portions 6 and 7 are added, and in the differential amplifier 9, the output from the connecting portion 10 between the impedance element Z ₈ and the capacitive element 5 and the output from the adder 8 are added. In addition to differential amplification, the output from the amplifier is fed back to the drive unit 4. Further, both the connecting portions 6 and 7 are connected to another differential amplifier 11, and this differential amplifier 11 is sequentially connected to the synchronous detector 12 and the DC amplifier 13.

According to the vibrating gyroscope constructed as described above, the drive device 4 drives the respective divided electrodes 2a, 2b.
By applying an AC voltage to the vibrator 3, the vibrator 3 can be self-oscillated in the X-axis direction. In this vibrating state, the output from each of the connecting portions 6 and 7 is the drive device 4
Is a combined output of the voltage supplied from the device and the voltage output through the divided electrodes 2a and 2b with the strain of the piezoelectric element 2. Therefore, by adding the two combined outputs by the adder 8 and inputting them to the differential amplifier 9, only the voltage generated with the vibration in the X-axis direction is extracted, and the extracted voltage is supplied to the drive device 4. By feeding back, the self-excited vibration of the vibrator 3 can be made stable.

Under the self-excited vibration of the vibrator 3, when the vibrator 3 is rotated around the Z axis, the vibrator 3 moves in the Y axis direction based on the Coriolis force. Vibration is generated, which causes a difference in the output voltage of the connecting portions 6 and 7. Therefore, by differentially amplifying both of these output voltages with the differential amplifier 11, it is possible to separately detect the voltage associated with the generation of the Coriolis force.

By the way, in the above-proposed vibration gyro shown in FIG. 4, the electrodes of one piezoelectric element 2 attached to one side surface of the vibrating body 1 are arranged in the width direction of the vibrating body 1. Since the electrodes are divided into the divided electrodes 2a and 2b, the width of each divided electrode is less than half the width of the vibrating body 1, and the divided electrodes 2a and 2b are formed on the same side surface of the vibrating body 1. Since it is positioned above, there is a problem that both the driving force of the vibrator 3 and the detection sensitivity of the Coriolis force decrease and the S / N decreases. The present invention has been made as a result of studying as a subject to solve the problems of the prior proposed technique, and an object of the present invention is to facilitate the assembling work of a vibrator and to provide an adhesive agent.
The fluctuation of driving conditions due to the influence of
The change in the drive
In addition to reducing the output during movement, the detection sensitivity of Coriolis force, and thus of angular velocity, is sufficiently increased to improve the S / N ratio.
It is to provide a vibration gyro with greatly improved values.

[0014]

A vibrating gyroscope according to the present invention has a first piezoelectric element on a first side surface of a vibrating body having a polygonal transverse cross section, and a second piezoelectric element parallel to the first side surface. The second piezoelectric elements are attached to the side surfaces of the piezoelectric element while being biased to one side of each of the side surfaces, and the width of each piezoelectric element is set to the width of the attached side surface.
As a dimension exceeding half the width constitutes a vibrator, each of the first and second piezoelectric elements of the transducer, in conneted to one vibrator vibrating drive means via a respective impedance element While connecting the connecting portion of each piezoelectric element and the impedance element to the driving means through, for example, an adder and a differential amplifier that performs a differential between the addition output from the piezoelectric element and the reference AC voltage in order, Each connection is also connected to a differential amplifier that performs the differential of the outputs of those connections.

According to another vibrating gyroscope of the present invention, a first piezoelectric element is provided on a first side surface of a vibrating body having a polygonal cross-sectional shape, and a second side surface parallel to the first side surface. The second piezoelectric element is attached to one side of each side so that the width of each piezoelectric element is half the width of the attached side surface.
As a dimension exceeding the amount constitutes a vibrator, each of the first and second piezoelectric elements of the transducer, in conneted to one vibrator vibrating drive means via a respective impedance elements, each The connection portion between the piezoelectric element and the impedance element is connected to the driving means through the respective differential amplifiers and adders that perform the differential between the output of each connection portion and each reference AC voltage, while each of the connection portions is connected. Section is also connected to a differential amplifier that performs a differential operation of the outputs of these connection sections, or the connection section between each piezoelectric element and the impedance element is connected to the output of each connection section and each reference AC voltage. Each of the differential amplifiers and the adder for performing the differential of the above is sequentially connected to the driving means, while the respective differential amplifiers are connected to each other and the differential outputs of the respective differential amplifiers are connected to each other. Other differential to do Which are connected to a width unit.

In each of the above-mentioned vibration gyros, more preferably, each reference AC voltage is a voltage at a connecting portion between the capacitive element connected to the driving means via the impedance element and the impedance element.

[0017]

In the vibrating gyroscope as described above, the first piezoelectric element is provided on the first side surface of the vibrating body having a polygonal cross section.
Then, the second side surface is parallel to the first side surface and the second side surface is formed.
By sticking together the piezoelectric elements on one side of each of the side surfaces, and by configuring the vibrator so that the width dimension of each piezoelectric element exceeds half the width of the sticking side surface. , the vibrator is allowed dynamic driving the side surface parallel to the direction in which the bonding the two piezoelectric elements. In this case , each piezoelectric element having a width exceeding half the width of the sticking side surface must be positioned across the neutral plane of the vibration in the driving direction of the vibrator. At the time of vibration, each piezoelectric element simultaneously generates an electric charge associated with its extension and an electric charge associated with compression, and a large part of those charges having mutually opposite signs are canceled out within each piezoelectric element. So
It is possible to effectively reduce the piezoelectric element output with respect to the driving vibration of the vibrator. Moreover, both the first and second piezoelectric element in this case, Propelled by one a width exceeding half the width of the bonded sides of each of them to vibration Doko, the direction of which is perpendicular to that of the driving direction When Coriolis force is generated,
That each piezoelectric element detects the Coriolis force in a posture perpendicular to the direction of action of the Coriolis force, in opposite directions of the piezoelectric elements to each other, and each piezoelectric element is distorted in the same direction throughout its Together with this, the output of each piezoelectric element can be made sufficiently large, and thereby the detection sensitivity for the Coriolis force of the vibration gyro can be increased. Therefore, while making the output voltage due to the Coriolis force sufficiently large as described above, by advantageously reducing the output voltage for vibration in the driving direction, which is essentially unnecessary for detecting the Coriolis force, S / N
Can be much higher than in the prior art.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, in which the same parts as those described in FIG. 4 are designated by the same reference numerals. In this embodiment, as well as adhering the first piezoelectric element 20 on one side 1a of the vibration member 1 which cross-sectional shape forms a rectangle, the opposing side surface 1b which forms a parallel to the side surface 1a, the second piezoelectric element 21 And both the piezoelectric elements 20 and 21 are positioned so as to be offset to one side of the respective side surfaces 1a and 1b , and the width dimension of each piezoelectric element 20 and 21 is adjusted.
Of the piezoelectric element 20 and 21 and the impedance element of each of the piezoelectric elements 20 and 21.
By connecting the driving device 4 via Z ₁ and Z ₂ and also connecting the driving device 4 to the capacitive element 23 via another impedance element Z ₃ , the AC voltage from the driving device 4 is The piezoelectric elements 20 and 21 and the capacitive element 23 can be applied simultaneously.

[0019] On the other hand, each of the impedance element Z _1, Z
₂ and the connecting portions 24 and 25 between the piezoelectric elements 20 and 21,
It is connected to the differential amplifier 9 via the adder 8, and the adder 8 adds the outputs from both of the connecting portions 24 and 25. Then, in the differential amplifier 9, the impedance element Z ₃ and the capacitive element 23 are added. The output from the connection section 26 and the output from the adder 8 are differentially amplified, and the differential output therefrom is fed back to the drive unit 4. By the way, as each of the impedance elements Z ₁ , Z ₂ and Z ₃ here, any type of resistance type, capacitance type and inductive type can be used.

Further, a connecting portion between the impedance elements Z ₁ and Z ₂ and the piezoelectric elements 20 and 21 is connected.
24 and 25 are replaced with other differential amplifiers 11 as in the prior art.
The differential amplifier 11 is sequentially connected to the synchronous detector 12 and the DC amplifier 13.

In such a vibrating gyro, the vibrator 22 can be self-oscillated in the X-axis direction of the three-dimensional orthogonal coordinate system by applying an AC voltage from the driving device 4 to the respective piezoelectric elements 20, 21. In such a self-excited vibration state, the output from each of the connection portions 24 and 25 is the drive device 4
And a voltage output from each of the piezoelectric elements 20 and 21 due to the strain of each of the piezoelectric elements 20 and 21. Therefore, by adding both combined outputs by the adder 8 and passing them through the differential amplifier 9, the piezoelectric elements 20, 21 are caused based on the vibration in the X-axis direction.
It is possible to extract only the voltage generated from the above, and by feeding back it to the drive device 4, the self-excited vibration of the vibrator 6 can be made sufficiently stable. In addition, here
The outputs from the piezoelectric elements 20 and 21 are as described above.
In addition, both piezoelectric elements 20 and 21
Small enough based on being located across the midplane
Becomes

Under such self-excited vibration of the vibrator 22, when the vibrator 22 is rotated around the Z axis, the vibrator 22 vibrates in the Y axis direction based on the Coriolis force. Occurs, which causes a difference in the output voltage of the connection portions 24 and 25. Therefore, both of these output voltages are differentially amplified by the differential amplifier 11 and sequentially passed through the synchronous detector 12 and the DC amplifier 13, whereby the voltage associated with the generation of Coriolis force can be separated and detected. .

Here, according to this vibrating gyroscope, in particular, the attachment area is large and the action direction of the Coriolis force is
In addition to detecting the Coriolis force by the two piezoelectric elements 20 and 21 positioned in the orthogonal posture , those piezoelectric elements
20, 21 are arranged on two side surfaces of the vibrating body 1 facing each other and are distorted in the opposite directions, and the same piezoelectric element is formed as a whole.
By distorting in the same direction over , the detection sensitivity can be sufficiently enhanced. Moreover, with this vibrating gyro
Are the piezoelectric elements of the vibrator 22 during self-excited vibration.
Combined with the small output from 20, 21, increase S / N
Can be improved.

FIG. 2 is a block diagram showing another embodiment of the present invention. In this example, the driving device 4 is connected to each piezoelectric element via each impedance element Z ₁ and Z _2.
20 and 21, and connected to the respective capacitive elements 31 and 32 via the other respective impedance elements Z ₄ and Z ₅ , and then to the impedance elements Z ₁ and Z ₂ and the piezoelectric element 2
1 in that the respective connection portions 24 and 25 with 0 and 21 are connected to the adder 35 via the respective differential amplifiers 33 and 34 which perform differential with the reference AC voltage. Be different.

Here, the differential amplifier 33 includes an output from the connecting portion 36 of the impedance element Z ₄ and the capacitive element 31, and a connecting portion
And an output from the 24 differentially amplified, the differential amplifier 34, the output from the connection portion 37 of the impedance element Z ₅ and the capacitor 32, and an output from the connection 25 to the differential amplifier. In addition, the adder 35 separates and detects only the voltage generated by the vibration of the vibrator 22 in the X-axis direction by adding both differential amplified outputs, and feeds back the detected voltage to the drive device 4. The stable self-excited vibration of the vibrator 22 is brought about.

In such a vibrating gyro, the Coriolis force during rotation of the vibrator 22 is
The output of 25 can be separately detected by inputting it to another differential amplifier 11 and making it differential.

Also by the vibrating gyroscope as described above, the respective piezoelectric elements 20 and 21 cause the self-excited vibration of the vibrator 22.
With position across the neutral plane, with a sufficiently large area, enhanced because it is attached to each of the opposing sides of the vibrating body 1, similarly to the embodiment described above, the detection sensitivity of the Coriolis force Rutotomoni , S / N can be effectively improved.

In the above description, in the detection system, the outputs of the connection parts 24 and 25 are directly input to the differential amplifier 11. However, as shown in FIG. By inputting the outputs from 33 and 34 to the differential amplifier 11, it is possible to detect the Coriolis force, and thus the angular velocity, as in the case shown in FIG. Further, in the present invention, the cross-sectional shape of the vibrating body 1 may be a polygonal shape of any even angle other than a quadrangle.

[0029]

As is apparent from the above description, according to the present invention, each piezoelectric element having a width dimension that exceeds half of the side surface width of two side surfaces of the vibrating body that are parallel to each other. and Ri by the be disposed in polarized allowed on one side of each side, it is possible to detect angular velocity at not sensitive, yet, reducing the output of each of the piezoelectric elements to the driving direction vibration of the vibrator Therefore , the S / N can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram showing another embodiment of the present invention.

FIG. 3 is a block diagram showing still another embodiment of the present invention.

FIG. 4 is a block diagram of a proposal of the present inventor prior to the present invention.

FIG. 5 is a block diagram showing a conventional example.

FIG. 6 is a block diagram showing another conventional example.

[Explanation of symbols]

1 vibrating body, 1a, 1b side surface, 4 driving device, 8, 35 adder, 9, 11, 33, 34 differential amplifier 12 synchronous detector, 13 DC amplifier, 20, 21 piezoelectric element, 22 oscillator, 23, 31, 32 Capacitance element 24, 25, 26, 36, 37 Connection Z ₁ , Z ₂ , Z ₃ , Z ₄ , Z ₅ Impedance element

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-58-160809 (JP, A) Fukukaihei 4-38513 (JP, U) 1986 Grant-in-Aid for Scientific Research (General Research (B)) Research Results Report (Subject Number: No. 60460142), "Piezoelectric Vibration Gyro-Directional Sensor", March 1987, Principal Investigator Tadashi Kino (Faculty of Engineering, Yamagata University), p. 8-12 NIKKEI ELECTRONIC S 1992.5.11 (No.553) P. 90-91, "Akai Denki to Murata Manufacturing to Launch Small Piezoelectric Vibratory Gyro"

Claims (4)

(57) [Claims] 1. A first vibrating body having a polygonal cross section.
A first piezoelectric element on a side surface of the first piezoelectric element, a second piezoelectric element on a second side surface parallel to the first side surface, and both sides thereof.
Stick it on one side of the surface and set the width of each piezoelectric element to
Oscillator formed by a dimension that exceeds half of the width of the bonded sides,
When each of the first and second piezoelectric elements is connected to one vibration driving means via each impedance element, the sum of the respective outputs of the connecting portion of each piezoelectric element and the impedance element is defined as the reference AC voltage. A vibrating gyro, wherein the output of the connecting portion is differentially extracted from each other while being differentially fed back to the driving means. 2. A first vibrating body having a polygonal cross section.
A first piezoelectric element on a side surface of the first piezoelectric element, a second piezoelectric element on a second side surface parallel to the first side surface, and both sides thereof.
Stick it on one side of the surface and set the width of each piezoelectric element to
Oscillator formed by a dimension that exceeds half of the width of the bonded sides,
When each of the first and second piezoelectric elements is connected to one vibration driving means via each impedance element, each output of the connection portion between each piezoelectric element and the impedance element is differentiated from the reference AC voltage. Then, the sum of the respective differential outputs is fed back to the driving means, while the respective outputs of the connecting portion are differentially extracted from each other and taken out. 3. A first vibrating body having a polygonal cross section.
A first piezoelectric element on a side surface of the first piezoelectric element, a second piezoelectric element on a second side surface parallel to the first side surface, and both sides thereof.
Stick it on one side of the surface and set the width of each piezoelectric element to
Oscillator formed by a dimension that exceeds half of the width of the bonded sides,
When each of the first and second piezoelectric elements is connected to one vibration driving means via each impedance element, each output of the connection portion between each piezoelectric element and the impedance element is differentiated from the reference AC voltage. Then, the sum of the respective differential outputs is fed back to the driving means, while the respective differential outputs are differentially extracted from each other. 4. The reference AC voltage is a voltage at a connecting portion between a capacitive element connected to a driving means via an impedance element and the impedance element. The vibrating gyroscope according to item.