JPH08320233A - Sensitivity temperature characteristic adjusting method for vibrating gyroscope - Google Patents

Abstract

PURPOSE: To provide a adjusting method that can adjust the sensitivity temperature characteristic of a vibrating gyroscope easily at a low cost. CONSTITUTION: A vibrating gyroscope 10 includes a vibrator of equilateral triangle pole shape, for instance. Piezoelectric elements 14a, 14b, 14c are formed at the side face of a vibrator 12. An oscillating circuit 24 is connected between the piezoelectric elements 14a, 14b and the piezoelectric element 14c, and the vibrator 12 is bendingly vibrated in an orthogonal direction to the face with the piezoelectric element 14c formed. A ridgeline part of the vibrator 12 opposed to the piezoelectric element 14c is chipped to adjust resonance frequency, oscillating frequency, anti-resonance frequency or anti-resonance frequency in the bending vibrating direction at the non-rotating time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of adjusting the sensitivity temperature characteristic of a vibration gyro, and more particularly to a method of adjusting the sensitivity temperature characteristic of a vibration gyro for adjusting the relationship between the detection sensitivity of rotational angular velocity and temperature.

[0002]

2. Description of the Related Art FIG. 1 is a perspective view showing an example of a vibrating gyro, and FIG. 2 is a sectional view thereof. Vibrating gyro 10
Includes a vibrating body 12 having, for example, a regular triangular prism shape. Vibrating body 1
The material 2 is generally made of a material that causes mechanical vibration, such as elinvar, iron-nickel alloy, quartz, glass, crystal, and ceramic.

Piezoelectric elements 14a, 14b and 14c are formed on three side surfaces of the vibrating body 12, respectively. The piezoelectric element 14a includes a piezoelectric layer 16a made of, for example, piezoelectric ceramic, and electrodes 18a, 20 are provided on both surfaces of the piezoelectric layer 16a.
a is formed. Then, one electrode 20a is bonded to the vibrating body 12. Similarly, the piezoelectric elements 14b and 14c include piezoelectric layers 16b and 16c, and electrodes 18b and
20b and electrodes 18c and 20c are formed. Then, one electrode 20 of these piezoelectric elements 14b, 14c
b and 20c are bonded to the vibrating body 12.

When using the vibrating gyroscope 10, as shown in FIG. 3, resistors 22 are provided on the piezoelectric elements 14a and 14b.
a and 22b are connected. These resistors 22a, 22b
The oscillation circuit 24 is connected between the piezoelectric element 14c and the piezoelectric element 14c. The output signal of the oscillation circuit 24 is used as a drive signal for causing the vibrating body 12 to flexurally vibrate.
4b. Then, the signal output from the piezoelectric element 14c due to the bending vibration of the vibrating body 12 is transmitted to the oscillation circuit 2
Returned to 4. Further, the piezoelectric elements 14a and 14b are
It is connected to the differential circuit 26. The differential circuit 26 is connected to the detection circuit 28, and the detection circuit 28 is connected to the smoothing circuit 30. The output signal of the smoothing circuit 30 is, if necessary,
It is amplified by the amplifier circuit.

When not rotating, the vibrating body 12 flexurally vibrates in the direction orthogonal to the surface on which the piezoelectric element 14c is formed. In this state, the bending states of the piezoelectric elements 14a and 14b are the same, and the signals output from the piezoelectric elements 14a and 14b by this bending are the same. Therefore, no signal is output from the differential circuit 26 during non-rotation. When the vibrating gyro 10 rotates about the axis of the vibrating body 12, a Coriolis force acts in a direction orthogonal to the vibrating direction when it is not rotating. This Coriolis force changes the direction of flexural vibration of the vibrating body 12. Since the piezoelectric elements 14a and 14b are arranged so as to be symmetrical with respect to the bending vibration direction of the vibrating body 12 when there is no rotation, the piezoelectric elements 14 due to the Coriolis force.
The changes in the bent states of a and 14b are opposite to each other. Therefore, the piezoelectric elements 14a and 14b output signals of opposite polarities corresponding to the Coriolis force. Therefore, the differential circuit 2
From 6, a large output signal corresponding to the Coriolis force is obtained. The output signal of the differential circuit 26 is detected by the detection circuit 28 and further smoothed by the smoothing circuit 30. The output signal of the smoothing circuit 30 is a signal corresponding to the Coriolis force, and by measuring the output signal of the smoothing circuit 30, the rotational angular velocity applied to the vibration gyro 10 can be detected.

[0006]

In such a vibration gyro, the detection sensitivity varies depending on the change in ambient temperature. The variation of the detection sensitivity is, for example, that the detection sensitivity becomes larger as the temperature rises, conversely the detection sensitivity becomes smaller as the temperature rises, or the detection sensitivity becomes smaller even if the temperature rises or falls. . To adjust the sensitivity temperature characteristic of the vibration gyro,
For example, a temperature sensitive element such as a thermistor is used as a gain determining resistance of an amplifier circuit, or a thermistor is inserted between two piezoelectric elements for detection, and the sensitivity temperature characteristic of a vibration gyro is adjusted by changing the resistance of these thermistors. is there.

However, in such a method, an expensive element such as a thermistor must be used, which results in high cost. Further, in order to adjust the sensitivity temperature characteristic of the vibration gyro to a desired state, it is necessary to select an appropriate thermistor, and it is difficult to adjust the characteristic.

Therefore, a main object of the present invention is to provide an adjusting method capable of easily and inexpensively adjusting the sensitivity temperature characteristic of the vibration gyro.

[0009]

SUMMARY OF THE INVENTION The present invention is a method for adjusting the sensitivity temperature characteristic of a vibrating gyroscope including a columnar vibrating body for flexural vibration, wherein the resonance frequency in the flexural vibration direction of the vibrating body when not rotating. It is a method of adjusting the sensitivity temperature characteristic of the vibration gyro, in which the oscillation frequency, anti-resonance frequency or detuning frequency is adjusted. In this method of adjusting the sensitivity temperature characteristic of the vibrating gyroscope, the resonance frequency, the oscillation frequency, the anti-resonance frequency or the detuning frequency in the bending vibration direction of the vibrating body during no rotation is adjusted by changing the cutting amount of the vibrating body. .

[0010]

[Function] By adjusting the resonance frequency, the oscillation frequency, the anti-resonance frequency or the detuning frequency in the bending vibration direction of the vibrating body at the time of no rotation, the point where the detection sensitivity of the vibration gyro becomes maximum is the high temperature side or the low temperature side. Move to. When the point at which the maximum detection sensitivity is moved to the high temperature side, the graph shows the temperature on the horizontal axis and the detection sensitivity on the vertical axis, the detection sensitivity shows an upward trend. When the point at which the maximum detection sensitivity is moved to the low temperature side, the detection sensitivity shows a downward sloping tendency. Such adjustment is possible by adjusting the cutting amount of the vibrating body.

[0011]

According to the present invention, a vibrating gyro having desired characteristics can be obtained only by changing the cutting amount of the vibrating body. Therefore, it is not necessary to use an expensive element such as a thermistor. Further, it is only necessary to adjust the cutting amount of the vibrating body while measuring the characteristics of the vibration gyro, and it is possible to easily adjust the sensitivity temperature characteristics of the vibration gyro.

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

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the vibration gyroscope 10 shown in FIGS. 1 and 2, in order to adjust its sensitivity temperature characteristic, the resonance frequency, the oscillation frequency, the anti-resonance frequency or the detuning frequency of the flexural vibration of the vibrating body 12 at the time of no rotation Is adjusted. As an adjusting method, the ridgeline portion of the vibrating body 12 facing the surface on which the piezoelectric element 14c is formed is scraped with a file or the like. The frequency is adjusted by adjusting the cutting amount of the vibrating body 12.

In the vibration gyro 10, the piezoelectric element 14
The frequency in the direction orthogonal to the a-forming surface is f _L , and the piezoelectric element 14
b, the frequency in the direction orthogonal to the formation surface is f _R , and the piezoelectric element 14
If the frequency in the direction orthogonal to the c-forming surface is f _C and the frequencies in all directions are the same, (f _L , f _C ,
f _R ) = (0,0,0). Here, assuming that f _C is a variable and (f _L , f _C , f _R ) = (0, x, 0), x> 0, that is, the frequency in the direction orthogonal to the surface on which the piezoelectric element 14c is formed is 2 When the frequency is greater than the frequency in the direction,
As shown in, the point where the detection sensitivity is maximized moves to the high temperature side. Further, when x <0, that is, when the frequency in the direction orthogonal to the surface on which the piezoelectric element 14c is formed is smaller than the frequencies in the other two directions, the point at which the detection sensitivity becomes maximum moves to the low temperature side. Therefore, when centering on a constant temperature, when x> 0, the sensitivity temperature characteristic of the vibrating gyroscope shows an upward tendency, and when x <0, it shows a downward tendency. Further, when x = 0, almost flat characteristics are exhibited.

As an experimental example, for the detuning frequency, (f
_L , f _C , f _R ) = (0, 0, 0), (f _L , f _C , f
_R ) = (0, 20, 0), (f _L , f _C , f _R ) =
The sensitivity temperature characteristic at (0, -20, 0) was measured, and the result is shown in FIG. FIG. 6 shows how the detection sensitivity fluctuates with respect to temperature changes, with reference to the sensitivity at room temperature, 25 ° C. As can be seen from FIG. 6, when f _C is higher than f _L and f _R by 20 Hz, the detection sensitivity of the vibration gyro is high on the high temperature side and low on the low temperature side. Also, f _C is 20 H from f _L and f _R
When z was low, the detection sensitivity of the vibration gyro was low on the high temperature side and high on the low temperature side. Furthermore, f _L , f _C ,
When f _R was the same, the point at which the sensitivity became maximum was around 25 ° C., and almost flat characteristics were exhibited within the operating temperature range of the vibration gyro.

In this way, the ridgeline portion of the vibrating body 12 is shaved,
The detection sensitivity of the vibration gyro 10 can be set to a desired tendency by adjusting the frequency in the vibration direction during non-rotation. Therefore, unlike the conventional method, it is not necessary to use an expensive element such as a thermistor, and the detection sensitivity of the vibration gyro can be adjusted at low cost. Furthermore, since the cutting amount can be adjusted while observing the characteristics of the vibration gyro 10, desired characteristics can be easily obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a vibration gyro whose sensitivity temperature characteristic is adjusted.

FIG. 2 is a cross-sectional view of the vibrating gyro shown in FIG.

3 is an illustrative view showing a circuit for using the vibrating gyro shown in FIG. 1. FIG.

FIG. 4 is a graph showing a change in sensitivity when a frequency in a vibration direction during non-rotation becomes higher than frequencies in other vibration directions.

FIG. 5 is a graph showing a change in sensitivity when a frequency in a vibration direction during non-rotation becomes smaller than a frequency in another vibration direction.

6 is a graph showing sensitivity when the detuning frequency of the vibration gyro shown in FIG. 1 is changed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vibration gyro 12 Vibration body 14a, 14b, 14c Piezoelectric element 24 Oscillation circuit 26 Differential circuit 28 Detection circuit 30 Smoothing circuit

Claims (2)

[Claims] 1. A method of adjusting the sensitivity temperature characteristic of a vibration gyro including a columnar vibrating body for flexural vibration, comprising: a resonance frequency, an oscillation frequency, and an anti-resonance frequency in a flexural vibration direction of the vibrating body when not rotating. Alternatively, the detuning frequency is adjusted to adjust the sensitivity temperature characteristic of the vibration gyro. 2. The resonance frequency, the oscillation frequency, the anti-resonance frequency or the detuning frequency in the bending vibration direction of the vibrating body during non-rotation is adjusted by changing the cutting amount of the vibrating body. A method for adjusting the sensitivity temperature characteristic of the vibration gyro described.