JPH0791959A - Vibration gyroscope - Google Patents

Abstract

PURPOSE:To make it possible to compensate the temperature characteristic of detection sensitivity at a low cost. CONSTITUTION:A vibration gyroscope 10 contains a vibrator 12 which comprises a triangle pole shaped vibrator 14 an piezo-electric elements 16a, 16b and 16c. An oscillation circuit 26 is connected between the piezo-electric elements 16a and 16b and the piezo-electric element 16c. Moreover, output signals of the piezo-electric elements 16a and 16b are inputted to a differential circuit 28. The differential circuit 28 is connected to a synchronous detection circuit 30, which 30 is connected to a smoothing circuit 32. A capacitor 34 for temperature compensation is connected to between the piezo-electric element 16a and 16b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration gyro,
In particular, for example, the present invention relates to a vibration gyro utilizing bending vibration of a columnar vibrating body.

[0002]

2. Description of the Related Art FIG. 7 is an illustrative view showing one example of a conventional vibrating gyro. The vibrating gyro 1 includes a vibrating body 2 having, for example, a regular triangular prism shape. Piezoelectric elements 3a, 3b, 3c are formed on the side surfaces of the vibrating body 2, respectively. Piezoelectric elements 3a, 3
b is used for driving to vibrate and vibrate the vibrating body 2, and is also used for detecting to detect a signal corresponding to the rotational angular velocity. The piezoelectric element 3c is
It is used for feedback to drive the vibrator 2. The oscillation circuit 4 is connected between the piezoelectric elements 3a and 3b and the piezoelectric element 3c. The piezoelectric elements 3a and 3b are connected to the input ends of the differential circuit 5. The output terminal of the differential circuit 5 is connected to the synchronous detection circuit 6, and the synchronous detection circuit 6 is further connected to the smoothing circuit 7.

In the vibrating gyro 1, the vibrating body 2 flexurally vibrates in the direction orthogonal to the surface on which the piezoelectric element 3c is formed by the drive signal from the oscillating circuit 4. In this state, when rotating around the axis of the vibrating body 2, the vibrating body 2 is caused by Coriolis force.
Vibration direction changes. Thereby, the piezoelectric element 3 for detection
A difference between the output signals occurs between a and 3b, and the difference between the output signals is output from the differential circuit 5. Then, the output signal of the differential circuit 5 is detected and smoothed, so that the vibration gyro 1
It is possible to detect a signal corresponding to the rotational angular velocity applied to the.

[0004]

However, in such a vibration gyro, the detection sensitivity changes due to the change in the ambient temperature. The temperature characteristic of such detection sensitivity is determined by a combination of the temperature characteristics of the vibrating body portion, the oscillation circuit portion, and the detection circuit portion. Conventionally, it has been difficult to correct the temperature characteristic of the detection sensitivity of such a vibration gyro.

Therefore, a main object of the present invention is to provide a vibrating gyroscope capable of compensating the temperature characteristic of detection sensitivity at low cost.

[0006]

According to the present invention, a columnar vibrating body, a plurality of detection pieces formed on a side surface of the vibrating body for detecting a signal corresponding to a rotational angular velocity, and between the plurality of detection pieces. A vibration gyro including a temperature compensation capacitor connected thereto.

[0007]

The capacitance of the temperature compensating capacitor changes due to the change of the ambient temperature. The temperature characteristic of the detection sensitivity of the vibration gyro changes due to the change in capacitance.

[0008]

According to the present invention, by selecting the temperature compensating capacitor so as to have a characteristic opposite to the temperature characteristic of the vibration gyro, the temperature change of the detection sensitivity of the vibration gyro due to the change of the ambient temperature is canceled. You can Therefore, the detection sensitivity of the vibration gyro can be kept substantially constant regardless of changes in the ambient temperature. Moreover, the temperature compensating capacitor is inexpensive, and the cost for temperature compensation can be suppressed.

The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the drawings.

[0010]

1 is an illustrative view showing one embodiment of the present invention. The vibrating gyro 10 includes a vibrator 12. Oscillator 1
As shown in FIGS. 2 and 3, the reference numeral 2 includes a vibrating body 14 having, for example, a regular triangular prism shape. The vibrating body 14 is formed of a material that generally causes mechanical vibration, such as elinvar, iron-nickel alloy, quartz, glass, crystal, or ceramic.

Piezoelectric elements 16a, 16b and 16c are formed on three side surfaces of the vibrating body 14, respectively. The piezoelectric element 16a includes a piezoelectric layer 18a made of, for example, porcelain, and electrodes 20a and 22a are formed on both main surfaces of the piezoelectric layer 18a, respectively. Then, the one electrode 20a is bonded to the side surface of the vibrating body 14. Similarly, the piezoelectric element 16
b and 16c include piezoelectric layers 18b and 18c.
The electrodes 20b and 22b and the electrode 2 are provided on both main surfaces of b and 18c.
0c and 22c are formed. Then, one electrodes 20b and 20c of the piezoelectric elements 16b and 16c are bonded to the side surface of the vibrating body 14. Further, the ridgeline portion near the node point of the vibrating body 14 is supported by the supporting members 24a and 24b made of, for example, metal wires. These support members 24
The a and 24b are fixed to the vibrating body 14 by welding, for example.

The piezoelectric elements 16a and 16b are used as a drive for bending and vibrating the vibrating body 14, and also as a detection for detecting a signal according to the rotational angular velocity. The piezoelectric element 16c is used for feedback to drive the vibrating body 14. An oscillation circuit 26 is connected between the driving piezoelectric elements 16a and 16b and the feedback piezoelectric element 16c. The vibrating body 14 is flexibly vibrated by the drive signal from the oscillation circuit 26. Further, the piezoelectric elements 16a and 16b are connected to the differential circuit 28.
Connected to the input end of. The output terminal of the differential circuit 28 is connected to the synchronous detection circuit 30, and the synchronous detection circuit 30 is further connected to the smoothing circuit 32. In the synchronous detection circuit 30, the output signal of the differential circuit 28 is detected in synchronization with the signal from the oscillation circuit 26. In addition, the two piezoelectric elements 16 of the vibrator 12
A temperature compensating capacitor 34 is connected between a and 16b.

In this vibrating gyro 10, the oscillation circuit 26
Thus, the vibrating body 14 is flexibly vibrated in a direction orthogonal to the surface on which the piezoelectric element 16c is formed. At this time, the piezoelectric element 16
Since the excitation signals input to a and 16b are the same signal, no signal is output from the differential circuit 28. When rotating around the axis of the vibrating body 14 in this state, the vibration direction of the vibrating body 14 changes due to the Coriolis force. This causes a difference in output signal between the piezoelectric elements 16a and 16b,
A signal is output from the differential circuit 28. The output signal of the differential circuit 28 is detected by the synchronous detection circuit 30 and further smoothed by the smoothing circuit 32. The output signal of the differential circuit 28 is the vibrating body 1.
4 corresponds to the change in the vibration direction, the smoothing circuit 32
By measuring the output signal of, the rotational angular velocity applied to the vibration gyro 10 can be detected.

In order to correct the temperature characteristic of the detection sensitivity of the vibration gyro 10, a temperature compensating capacitor 34 is connected between the piezoelectric elements 16a and 16b. As shown in FIG. 4, the temperature compensating capacitor 34 has various characteristics, and a temperature compensating capacitor having appropriate characteristics is selected as necessary. In FIG. 4, CH is 0 ±
60ppm / ℃, PH is -150 ± 60ppm / ℃, R
H is -220 ± 60ppm / ℃, SH is -330 ± 60
It has characteristics of ppm / ° C., TH of −470 ± 60 ppm / ° C., and UJ of −750 ± 120 ppm / ° C.

In this vibrating gyroscope 10, as shown in FIG. 5, the detection sensitivity decreases as the capacitance of the temperature compensating capacitor 34 increases. On the contrary, when the capacitance of the temperature compensating capacitor 34 becomes smaller, the detection sensitivity becomes higher. Therefore, as the temperature rises, the capacitance of the temperature compensating capacitor 34 decreases and the detection sensitivity increases. Further, when the temperature becomes low, the capacitance of the temperature compensating capacitor 34 becomes large and the detection sensitivity becomes low.
Therefore, as shown in FIG. 6A, even in the vibration gyro having the characteristic that the detection sensitivity becomes lower as the temperature becomes higher, the temperature compensation capacitor having the characteristic shown in FIG. As shown in, it is possible to obtain the characteristic that the change of the detection sensitivity due to the change of the temperature is small.

If a temperature compensating capacitor whose capacitance increases as the temperature rises is used, FIG.
As shown in C of No. 1, it is possible to obtain the characteristic that the detection sensitivity decreases as the temperature increases. Therefore, if such a temperature compensating capacitor is used, it is possible to improve the characteristics of the vibration gyro that the detection sensitivity increases as the temperature increases. As described above, by selecting the temperature compensating capacitor having an appropriate characteristic, it is possible to reduce the fluctuation of the detection sensitivity of the vibration gyro due to the temperature change.

As described above, by connecting the temperature compensating capacitor 34 between the piezoelectric elements 16a and 16b, the temperature characteristic of the sensitivity of the vibration gyro 10 can be corrected. Such a temperature compensating capacitor is inexpensive and can reduce the cost of parts as compared with the case of using an expensive part such as a thermistor for temperature compensation.

Although the vibrating body 14 is formed in the regular triangular prism shape in the above-mentioned embodiments, it may be formed in another prismatic shape such as a quadrangular prism shape. A piezoelectric body may be used as the material of the vibrating body 14. In this case, an electrode is formed on the side surface of the vibrating body 14 instead of the piezoelectric element. In such a vibrator, a cylindrical shape can be used as the shape of the vibrating body. Even when using such a vibrator,
By connecting a temperature compensating capacitor between the detection electrodes, it is possible to obtain a vibration gyro having substantially constant sensitivity to changes in the ambient temperature.

[Brief description of drawings]

FIG. 1 is an illustrative view showing one embodiment of the present invention.

FIG. 2 is a perspective view showing a vibrator used in the vibrating gyro shown in FIG.

3 is a cross-sectional view of the vibrator shown in FIG.

FIG. 4 is a graph showing temperature characteristics of a temperature compensating capacitor used in the vibration gyro of FIG.

FIG. 5 is a graph showing the relationship between the capacitance of the temperature compensation capacitor and the sensitivity change rate of the vibration gyro.

FIG. 6 is a graph showing a sensitivity change rate of the vibration gyro and a sensitivity change rate of the vibration gyro when a temperature compensation capacitor is used.

FIG. 7 is an illustrative view showing one example of a conventional vibrating gyro.

[Explanation of symbols]

 10 Vibration Gyro 12 Vibrator 14 Vibrators 16a, 16b, 16c Piezoelectric Element 34 Temperature Compensating Capacitor

Claims (1)

[Claims] 1. A columnar vibrating body, a plurality of detection pieces formed on a side surface of the vibrating body for detecting a signal corresponding to a rotational angular velocity, and a temperature compensating capacitor connected between the plurality of detection pieces. Vibrating gyro including.