JP2583701B2 - Vibrating gyroscope and adjustment method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrating gyroscope used for detecting an angular velocity, and more particularly, to an excellent angular velocity detection sensitivity.
The present invention relates to a vibrating gyroscope having stable detection performance and a method for adjusting the same.

[0002]

2. Description of the Related Art Conventional vibration gyros of this type include:
FIG. 7 shows an example. The vibrator 5 is configured by attaching each of the piezoelectric elements 2, 3, and 4 to three sides of a vibrating body 1 having a triangular cross-sectional shape, and one of those piezoelectric elements, for example, A drive AC voltage is applied to the piezoelectric element 4 to vibrate the vibrator 5 in the direction indicated by the arrow 6 in the figure, and the output voltage from the piezoelectric elements 2 and 3 is fed back to the drive circuit to reduce the vibration. It is controlled to be constant.

In such a vibrating gyroscope, when the vibrator 5 is rotated around the axis of the vibrating body 1 while being vibrated in the direction of arrow 6, the vibrator 5 Due to the Coriolis force, the piezoelectric elements 2 and 3 vibrate in a direction indicated by an arrow 7 orthogonal to the vibration direction. , 9 are detected.

In such a vibrating gyroscope, due to a difference in processing dimensions of the vibrating body 1, non-uniformity of the vibrating body structure, a sticking accuracy of the piezoelectric element, an unbalance of the vibrator support, and the like.
The resonance frequency of the vibration direction 6, wherein a large part to the resonant frequency does not match the direction 8,9, since the detection sensitivity by this is reduced, while scraped corners of the vibration member 1, This problem has been dealt with by adjusting and matching the resonance frequencies of the vibration direction 6 and the directions 8 and 9 .

[0005]

The adjustment of the resonance frequency according to the prior art is performed by independently adjusting the resonance frequency of each of the piezoelectric elements 2, 3, and 4 to achieve the adjustment. And, for example,
First, an AC voltage was applied only to the piezoelectric element 4, and the impedance and the phase angle at this time were measured by the output voltage of the piezoelectric element itself, and the piezoelectric element 4 was attached.
The corner portion 10 opposing the side surface is scraped off to provide a predetermined resonance frequency. Hereinafter, the other piezoelectric elements 2 and 3 are similarly set so that the resonance frequency in each direction becomes a predetermined value. This is done by cutting off the parts.

However, even if the vibration direction is the same, the resonance frequency of the vibrator 5 is slightly different depending on the magnitude of the amplitude of the bending vibration. In general, as the amplitude of the bending vibration increases, the resonance frequency increases. The resonance frequency will decrease.

[0007] In this connection, FIG.
Regarding the prior art shown in FIG. 1, in actual use of the vibrator 5, the vibration amplitude in the vibration direction indicated by the arrow 6 is
The detection direction indicated by the arrow 7 , ie, the action of the Coriolis force
It is substantially greater than the direction of the vibration amplitude, the resonance frequency of the vibration direction where much smaller than the resonance frequency of the detected direction, as described above, quite possible to consider the difference in amplitude due to the vibration direction of the difference When the resonance frequency is adjusted independently for each of the attachment surfaces of the piezoelectric elements 2, 3, and 4, even if the vibrator 5 is actually operated using a vibrating gyroscope, It is impossible to expect an exact coincidence between the resonance frequency in the driving direction and the resonance frequency in the detection direction. Therefore, the detection sensitivity has to be reduced. There is a problem that the phase of the output voltage tends to fluctuate.

The present invention has been made in view of the above-mentioned problems of the prior art. In particular, the present invention is to make the resonance frequency of the vibrator coincide with high accuracy in each of the driving direction and the detection direction. The present invention provides a vibration gyro having high angular velocity detection sensitivity and a small variation in the phase of a detection voltage, and a method of adjusting the vibration gyro.

[0009]

SUMMARY OF THE INVENTION A vibrating gyroscope according to the present invention comprises a vibrating body having a polygonal cross section having at least two sides that are not parallel to each other, for example, two sides adjacent to each other across a corner . A piezoelectric element is formed by attaching each of the piezoelectric elements, and the piezoelectric elements are used for driving,
In a vibrating gyroscope that functions for feedback and detection, the resonance frequency in the driving direction of the vibrator and the driving direction
And the resonance frequency in the detection direction orthogonal to the above.

[0010] The adjustment method of this invention, particularly, the resonance frequency in the driving direction, strike the match detection direction of the resonance frequency perpendicular to the driving direction, the same phase AC voltage
Mutual alternating AC voltage is inverted with and phase, it
While simultaneously applying the voltage to each of the piezoelectric elements, the output voltage of each of the piezoelectric elements is measured, and a required portion is cut in accordance with the measurement result, for example, a phase difference.

[0011]

According to the adjusting method of the present invention, a pair is attached to at least two sides of the vibrating body that are not parallel to each other.
By simultaneously applying an AC voltage to each of the piezoelectric elements to be formed , the combined vibration state in the bending direction and the vibration component in the direction orthogonal to the respective side surfaces to which the piezoelectric elements are attached are converted by the piezoelectric elements. Since observation can be performed simultaneously, fine adjustment of the resonance frequency in each direction can be performed easily and sufficiently accurately.

According to the vibrating gyroscope adjusted by this method, the resonance frequency in the driving direction and the resonance frequency in the detecting direction match with high accuracy, so that the detection sensitivity of the angular velocity can be greatly improved and Stable detection performance with little phase fluctuation can be provided.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing an embodiment of the present invention. Here, the vibrating body 1 having a square cross section is
A pair of piezoelectric elements 11 and 12 is attached to two sides that are not parallel to each other to form a vibrator 5, and these piezoelectric elements 11 and 12 are used for driving, Used for feedback and detection.

In order to bring the resonance frequency of the vibrator 5 into coincidence with the adjustment, first, a driving AC voltage is applied to the terminals 13 and 14 of the piezoelectric elements 11 and 12, respectively. By driving the vibrator 5 and differentiating the output voltage of the terminals 13 and 14 from the reference AC voltage, the voltage generated at the piezoelectric elements 11 and 12 is measured by, for example, an oscilloscope.

[0015] Here, the differential output voltage, for example, as shown in FIG. 2 one of the piezoelectric element 11 as an example, with connecting the piezoelectric element 11 to the driving means 15 through an impedance element Z _1, the capacitor 16 is connected to the drive means 15 via another impedance element Z _2, and the output voltage of the terminal 17 as the reference alternating voltage, performed by the output voltage of the terminal 13 at the same differential, in which According to this, it is possible to measure the voltage generated in the piezoelectric element 11 due to the drive vibration caused by the application of the drive AC voltage.

When a driving AC voltage having the same phase is applied to the terminals 13 and 14, the vibrator 5 is driven by the piezoelectric element.
Based on the resultant force of 11, 12, the bending vibration occurs in the direction of arrow 18 in the figure, and each terminal is located near the resonance point of the bending vibration.
The output voltages of 13, 14 increase.

In this case, if there is a difference in the resonance frequency in the direction orthogonal to the respective side surfaces to which the piezoelectric elements 11 and 12 are attached,
Differences occur in the magnitudes and positions of the generated voltages of the piezoelectric elements 11 and 12. FIG. 3 is a diagram exemplifying this. When the driving AC voltage having the same phase is applied, for example, the resonance frequency in the direction orthogonal to the side surface on which the piezoelectric element 11 is attached has the piezoelectric element 12 attached. When the resonance frequency is higher than the resonance frequency in the direction orthogonal to the side surface, the phase of the voltage generated by the piezoelectric element 11
Of the generated voltage.

Therefore, in such a case, either the side surface of the vibrating body to which the piezoelectric element 11 is adhered or the side surface 19 opposed to the side surface to which the piezoelectric element 11 is adhered as shown in FIG. By doing so, the phase of the voltage generated by both piezoelectric elements 11 and 12,
Consequently, the resonance frequencies in the respective directions orthogonal to the sticking side surfaces of the respective piezoelectric elements 11 and 12 are matched.

Thereafter, a driving AC voltage having a phase inverted to each other is applied to each of the terminals 13 and 14, and the vibrator 5 is driven.
In the direction of arrow 20 in the figure , that is, the generation of Coriolis force.
Is vibrated in the raw direction in this, the phase of the generated voltage of the piezoelectric element 11, 12, when caused to vibrate in the direction of arrow 18, piezoelectric element
The phases of the generated voltages 11 and 12 are compared, for example, as shown in FIG. According to the example illustrated in FIG.
Since the vibration frequency in the 18 directions has a higher resonance frequency and the phase of the generated voltage is advanced, in this case, by cutting the corner 21 of the vibrating body 1 as shown in FIG. Arrow 18
The resonance frequency of the vibration in the direction is matched with the resonance frequency of the vibration in the direction of arrow 20.

Further, an in-phase driving AC voltage is applied to the respective terminals 13 and 14 to drive and vibrate the vibrator 5 in the direction of arrow 18, while driving the vibrator 5 in the direction indicated by arrow 22 in FIG. And each piezoelectric element during this rotation
The generated voltages of 11, 12
In relation to the generated voltages 11 and 12, a voltage waveform line as shown in FIG. 5 is formed, where the point A where all the voltage waveforms intersect and the phase does not move, and the generated voltage at the time of driving vibration is zero. Is measured, and as shown in the figure, when the phase of the point A where the phase does not move is advanced, as shown in the figure, the corner 23 or 24 of the vibrating body 1 in one diagonal direction. Is finely adjusted to bring the two points A and B into agreement. Here, when the phase of the zero cross point B is advanced,
Similar fine adjustment is performed by deleting one corner in the other diagonal direction.

As described above, the resonance frequencies in the respective directions are adjusted in accordance with the actual operation of the vibrator 5 so that the respective resonance frequencies in the driving direction and the detection direction can be matched with high accuracy. Therefore, according to the vibrating gyroscope constituted by the vibrator 5, it is possible to enhance the detection sensitivity of the angular velocity and to provide stable detection performance.

FIG . 6 is a view showing still another embodiment of the present invention. In this embodiment, piezoelectric elements 11 and 12 are attached to two side surfaces of a vibrating body 1 having a triangular cross section. When the vibrator 5 is configured, the two piezoelectric elements 11 and 12 function as driving, feedback, and detection.

[0023] Again, each of the terminals 13, 14 by applying a driving AC voltage while driving the vibrator 5, the generated voltage of the piezoelectric element 11, 12, be determined based on the reference alternating voltage Adjusts the resonance frequency.

When a driving AC voltage having the same phase is applied to the terminals 13 and 14, the vibrator 5 bends and vibrates in the direction of arrow 25 in FIG. In the vicinity of the vibration resonance point, the voltage generated by the piezoelectric elements 11 and 12 increases. At this time, if there is a difference between the resonance frequencies in the directions of arrows 26 and 27, which are orthogonal to the respective side surfaces to which the piezoelectric elements 11 and 12 are attached, a difference occurs in the magnitude and phase of the generated voltage of the piezoelectric elements 11 and 12. .

[0025] Therefore, the corners against the side surface which is bonded a piezoelectric element is advanced in phase, by cutting the corner portion 28 where shown in FIG. 6 (b), the resonance of the respective directions of arrows 26 and 27 Produces a frequency match.

[0026] and then, each of the terminals 13, 14
The driving AC voltages whose phases are mutually inverted are respectively applied to oscillate the vibrator 5 in the direction of arrow 29 in the figure, and the phase of the voltage generated by the piezoelectric elements 11 and 12 at this time is changed to the direction of arrow 25. 6, the vibrating body corners in the vibration direction in which the phase is advanced compared to the phases of the generated voltages when vibrated in the direction of FIG.
At (c), the corner 30 is cut off, so that the resonance frequency in the direction of arrow 25 is sufficiently close to that in the direction of arrow 29, preferably resulting in a coincidence of the two resonance frequencies.

Furthermore, terminals 13, 14 by applying a driving AC voltage of the same phase, when rotating the vibrator 5 in the direction of arrow 22, the resonance frequency of the driving direction and a resonance frequency of the detected direction By making fine adjustments in the same manner as in the above-described example, the two resonance frequencies are matched with excellent accuracy.

[0028] Therefore, when using such vibrator 5 to the vibration gyro, also as described above, can provide a high detection sensitivity to angular velocity, moreover, it can result in constantly stable detection performance .

[0029]

As described above, according to the present invention, the oscillator
The resonance frequency in the drive direction and the resonance frequency in the detection direction are
It is possible to easily match with high accuracy, and as a result, the detection sensitivity of angular velocity is sufficiently increased, and the phase fluctuation of the output voltage of the piezoelectric element during the rotation of the vibrator is effectively removed, and stable. It can provide detection performance.

[Brief description of the drawings]

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

FIG. 2 is a circuit diagram showing a differential example of an output voltage.

FIG. 3 is a diagram showing voltage waveforms of respective generated voltages.

FIG. 4 is a diagram showing a voltage waveform of a generated voltage.

FIG. 5 is a diagram showing a voltage waveform of a detection voltage.

FIG. 6 is a front view showing another embodiment.

FIG. 7 is a front view showing a conventional example.

[Explanation of symbols]

1 vibrator 5 vibrator 11, 11a, 12 pressure conductive elements 13, 14 terminal 19 side 21, 23, 24, 28, 30 corner

Claims (2)

(57) [Claims] 1. A vibrating body having a polygonal cross-sectional shape has a pair formed on at least two sides that are not parallel to each other.
The to each of the piezoelectric elements by sticking constitutes a vibrator, their piezoelectric element, for driving, a vibrating gyroscope used for the feedback and detection, the vibrator, the resonance frequency in the driving direction, that Direction to drive direction
A vibrating gyroscope that matches the resonance frequency in the intersecting detection direction. 2. A pair of vibrating bodies having a polygonal cross section are formed on at least two side surfaces which are not parallel to each other.
The to each of the piezoelectric elements by sticking constitutes a vibrator, their piezoelectric element, for driving, the vibration gyro is used for the feedback and detection, the resonant frequency in the driving direction, driving the
In order to match the resonance frequency in the detection direction orthogonal to the moving direction , the in-phase AC voltage and the AC voltage whose phases are inverted from each other
The vibrating gyroscope is characterized in that, while simultaneously applying the alternation to the respective piezoelectric elements forming a pair, the output voltages of the piezoelectric elements are measured, and a required portion of the vibrating body is cut in accordance with the measurement result. Adjustment method.