JPH03150409A - Vibration gyro - Google Patents

Abstract

PURPOSE:To prevent the position precision between vibrators from deteriorating and to prevent the lateral vibration of an arm member from expanding by joining a single vibrator for driving with each arm member. CONSTITUTION:Vibrators 28 for driving which can be joined with arm members 1 and 2 of the gyro are provided with electrodes 30 and 31 over the entire surfaces of piezoelectric materials which cross a Y axis at right angles, and one electrode 31 is cut in a Z-axis direction at the width-directional center part into two divided electrodes 31A and 31B which are separated in an X-axis direction. Those vibrators 28 for driving are joined with the arm members 1 and 2, the electrode 30 is grounded, and the divided electrodes 31A and 31B are connected to an oscillator 33 through variable resistors 32A and 32B, and 32C and 32D for use.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vibrating gyroscope that detects Coriolis force for the purpose of detecting angular velocity, and in particular to a driving vibration gyroscope that effectively reduces offset output. It's about children.

[Conventional technology]

As a conventionally known vibrating gyroscope, there is one shown in FIG. 8, for example.

This means that the lower ends of two arm members 41 and 42, which extend parallel to each other in the Z-axis direction of the three-dimensional coordinate system and are located at a predetermined interval in the Y-axis direction, are connected to the base part 43. The integrally connected vibrating structure 44 is attached to the base 4 via a support member 45.
6, and a detection means 47 protruding in the X-axis direction is provided on the base portion 43 of the vibrating structure 44, and one surface of each arm member 41, 42 perpendicular to the Y-axis, the outer surface in the figure. It is constructed by providing drive vibrators 48 and 49, respectively.

In such a vibrating gyroscope, for example, the driving vibrator 48
．． When an AC voltage is applied to 49 and the arm members 41 and 42 are vibrated symmetrically in the Y-axis direction by a piezoelectric method, an electromagnetic method, etc., the vibrating structure 44 is rotated around two axes at an angular velocity ω. Coriolis forces Fc in opposite directions in the X-axis direction are generated in each of the arm members 41 and 42 that are moving at a speed of {circle around (2)} at a certain moment.

Here, since the speeds of the arm members 41 and 42 alternately change, the Coriolis force Fc is generated in a manner modulated by the frequency of the arm members 41 and 42, and the vibrating structure 44 is On the other hand, it vibrates torsionally around the Z-axis, and the torsional angle is proportional to the Coriolis force FC and, in turn, to the angular velocity ω.

Therefore, in this conventional device, the magnitude of the torsional vibration is
A piezoelectric method,
Detection is performed using an electromagnetic method or the like. For example, in a piezoelectric method using a bimorph element or the like, torsional vibration is converted into bending vibration of the detection means 47, and the charge generated by the bimorph element according to the amount of deflection is converted into a voltage. It is decided to extract and detect as follows.

However, in this conventional technique, vibrations of the arm members 41 and 42 are caused to be caused by the vibration of the arm members 41 and 42 due to unbalance of mass and unbalance of length of each arm member 41 and 42.
3, the detection means 47 outputs a signal generated by the unnecessary vibration, even though the angular velocity ω is zero. First, there is a problem in that a state similar to that in which Coriolis force is being detected, that is, an offset occurs, resulting in a decrease in the S/N ratio and, ultimately, in the detection sensitivity.

For this reason, the applicant previously proposed a vibrating gyroscope as shown in perspective views in FIGS. 9 and 10 as a vibrating gyroscope that causes less offset.

In the structure shown in FIG. 9, two extending arm members 1.2 are interconnected at their lower ends by a base portion 3 to form a vibrating structure 4, as described in the prior art. , a support member 5 which also serves as a detection means is attached to the base portion 3 of the vibrating structure 4.
is provided to protrude downward in the Z-axis direction, and the lower end of the support member 5 is fixed to the base 7, and each arm member 1, 2
Drive vibrators 8 and 9 are provided on one surface facing in the direction perpendicular to the Y-axis, which is also the outer surface in the figure, and the detection means here, that is, the support member 5, is Electrodes are provided on each opposing surface perpendicular to the Y-axis or the X-axis of the piezoelectric material 10 polarized in the direction, in this example, on the opposing surface perpendicular to the Y-axis, and each of the electrodes is divided into two in the X-axis direction. Two divided electrodes 12, 13 and 14.
15 (not shown).

In addition, the vibrating gyroscope shown in FIG.
The detection means 16 is fixed to the support member 6 on either one of the surfaces orthogonal to the Y axis or the The structure is somewhat different from that of the vibrating gyroscope shown in FIG. 9 in that it is provided with.

Note that the detection means 16 in this example has electrodes 18 and 19 formed on each opposing surface of a piezoelectric material 17 that has been polarized in the Z-axis direction and perpendicular to the Y-axis.

In these vibrating gyroscopes, the driving vibrator 8.9
When an alternating current voltage is applied to the oscillating gyroscope and the vibrating gyroscope is rotated around the Z axis while symmetrically vibrating each arm member 1.2 in the Y-axis direction, each arm member 1. , 2, Coriolis forces Fc in opposite directions are generated in the X-axis direction, and as a result, a torsional moment ML is generated in the vibrating structure 4, and the vibrating structure 4 is rotated around the Z-axis. , vibrates torsionally with respect to the base 7.

Therefore, here, the angular velocity ω is detected by extracting the torsional shear stress acting on each of the support members 5 and 6 due to the torsional moment Mt as a voltage using the respective detection means 5.16 shown in Fig. 9.10. do.

Thus, according to these vibrating gyroscopes, the arm members 1.
Due to the unbalanced mass and unbalanced length of the arm members 1.2 and 2, vibrations of the arm members 1.2 cause unnecessary vibrations of the base part 3 in the Y-axis direction. Even if bending vibrations occur in the members 5, 6, the detection means 5, 16 have no sensitivity in principle to such bending vibrations, so even though the angular velocity ω is zero, , the occurrence of a situation as if the Coriolis force Fc is being detected, that is, the occurrence of offset is small, and the tolerance range for the unbalance of the arm members 1 and 2 can be widened, which is advantageous for the production efficiency of the vibrating gyroscope. can be improved.

[Problem to be solved by the invention]

However, even in these vibrating gyroscopes, when the driving vibrators 8.9 are bonded to the surfaces of the arm members 1 and 2 perpendicular to the Y axis using adhesive, for example, variations in the thickness of the adhesive layer may occur. For other reasons, as illustrated in the plan view of FIG. 12, when the driving vibrator 8 is joined at an angle θ to the plane of the arm member 1 orthogonal to the Y axis, the driving vibrator 8. When an AC voltage is applied to the arm member 9 to vibrate the arm member 1.2, in addition to the vibration in the Y-axis direction, a lateral vibration as shown by the arrow φ in the figure is generated in the arm member l, in the X-axis direction. This acts as a torsional vibration on the support members 5, 6, causing a slight offset in the detection means 5.16.

Note that, as shown in FIG. 13, this means that the drive vibrator 8 is joined in a state where it is deviated by a distance δ in the X-axis direction with respect to the center line of the arm member l and thus the vibrating structure 4. The same is true in this case, and in this case, lateral vibration as shown by the arrow φ is likely to occur, and the performance of the vibrating gyroscope is forced to deteriorate.

Therefore, in order to reduce such offsets, the general method is to synchronously detect and rectify the output from the detection means 5.16 to convert it into DC, and then add or subtract the remaining DC component to a separately provided reference voltage to make it zero. It has been adopted.

However, since the sensitivity of the detection means 5 and 16 changes sensitively as the environmental temperature changes, and the amount of offset also changes accordingly, it is originally preferable to reduce the lateral vibration itself, and for this purpose, For example, as disclosed in Japanese Unexamined Patent Publication No. 19713/1983, two drive units are provided on the outer surface of each arm member, spaced apart from each other in a direction (X-axis direction) perpendicular to the vibration direction of the arm member. A vibrating gyroscope has been proposed in which a vibrator is attached and the driving voltage of each vibrator is adjusted.

By the way, according to this proposed technology, it is necessary to join each of the two drive vibrators at predetermined separated positions with high precision, but in reality, when joining them,
In addition to the accuracy in the X-axis direction, it is also extremely difficult to ensure accuracy in the Z-axis direction, and in particular, there is a problem that a decrease in the joining accuracy in the Z-axis direction amplifies the lateral vibration of the arm member.

The present invention advantageously solves the problems of the prior art, and can effectively prevent the lateral vibration of the arm member and effectively reduce the offset output even when the environmental temperature changes. This provides a high-performance vibrating gyroscope.

[Means to solve the problem]

The vibrating gyro of this invention particularly includes two arm members,
In a vibrating structure consisting of a base section interconnecting one end of each of these arm members, each driving vibrator to be joined on the outer surface perpendicular to the Y-axis of both arm members is made of a negative piezoelectric material. , an electrode is provided on each plane perpendicular to the Y-axis, and at least one of these electrodes is divided into two or three parts in the X-axis direction, and the voltage applied to these divided electrodes can be freely adjusted. That is.

[For production]

According to the vibrating gyroscope of the present invention, it is sufficient to connect a single driving vibrator to each arm member of the vibrating structure.
It is possible to effectively eliminate the joining error in the Z-axis direction of the drive vibrator as in the proposed technique, and therefore, the possibility of expansion of lateral vibration is sufficiently eliminated.

Furthermore, the occurrence of lateral vibrations in the arm member is advantageously reduced by adjusting the alternating current voltage applied to the split electrodes of the single drive vibrator, and as a result, the offset output is also sufficiently reduced. It turns out.

Thus, with this vibrating gyroscope, the Coriolis force can be detected with high accuracy at all times without being affected by the environmental temperature and with a relatively easy joining operation of the drive vibrator.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a perspective view illustrating a driving vibrator which is a main part of the present invention, and this driving vibrator is shown in FIGS.
It can be applied to the vibrating gyroscope shown in FIG.

Drive vibrator 2 of this example that can be connected to each arm member
8 is a piezoelectric material 29 having a rectangular hexahedral shape, for example.
, electrodes 30 and 31 are provided over the entire surface of each surface perpendicular to the Y axis, and one electrode, here electrode 31, is moved in the Z axis direction at the center of its width direction. 2 cut and separated in the X-axis direction
31A of divided electrodes.

31B, and here, these divided electrodes 31A, 31B are formed by providing grooves 29A in the Z-axis direction from the electrode 31 to the piezoelectric material 29 using a precision cutting machine or the like. can do.

Note that it goes without saying that the divided electrodes 31A and 31B can be formed directly by printing, photo-etching, etc. the electrode material without providing the electrode 31 in advance.

The drive vibrator 28 configured in this manner can be applied in place of each of the drive vibrators 8 and 9 shown in FIGS. 9 and 10, and its applied state is shown in a plan view. It will look like Figure 2.

Under such application conditions, one undivided electrode 30 of each drive vibrator 28 is grounded, while each divided electrode 31A, 31B is connected to each variable resistor 32A, 32B, 32C, 32D. and the respective divided electrodes 31A,
31B. The AC voltage from the oscillator 33 is controlled by variable resistors 32A and 32B so that the offset output from the detection means 5 and 16 is the lowest when the angular velocity ω is zero.
, 32C, and 32D, respectively.

Therefore, here, as shown in FIG. 12, for example, when at least one driving vibrator 28 is joined to the arm member at an angle with respect to the plane perpendicular to the Y axis, and when the first
As shown in Figure 3, even when the vibration structure 4 is joined to one side with respect to the center line, the lateral vibration of the arm member can be sufficiently reduced to improve the accuracy of Coriolis force detection. It can be greatly improved.

FIG. 3 is a perspective view showing another embodiment of the driving vibrator, in which a single piezoelectric material 29 is provided with electrodes 30, 31 respectively in the same manner as in the previously described embodiment. , one electrode 31 is divided into three divided electrodes 31A, 31
B, 31C, and here are equally divided in the X-axis direction.

Such a driving oscillator 28 can be applied as shown in FIG. As mentioned, one of the undivided electrodes 3
0 are mutually grounded, and each divided electrode 31A, 3
1B is a variable resistor 32A.

Grounded to the oscillator 33 via 328, 32C, 32D,
The voltage supplied to each divided electrode 31A, 31B is adjusted by variable resistors 32A, 32B, 32C, 32D so that the offset output of the detection means 5.16 is the lowest, while each divided electrode 31C is connected to an oscillator 33. By connecting, the vibration of the arm member 1.2 in the Y-axis direction is extracted as a voltage and fed back to the oscillator 33, thereby making it possible to control the vibration amplitude and other parameters.

FIG. 5 is a perspective view showing still another embodiment of the present invention, in which a bimorph type vibrator is used not only as a driving vibrator but also as an arm member and a vibration state extraction means. It is what makes it work.

Here, a drive vibrator 28 having the same configuration as that described in FIG.
An electrode 30 is provided on one surface perpendicular to the Y-axis, and an electrode 31 is provided on the other surface, and the electrode 31 is divided into two divided electrodes 31A and 31B separated in the X-axis direction.
A drive vibrator 28 is bonded to the piezoelectric material 35, and electrodes 36 and 37 are provided on the other surface of the thin plate 34 perpendicular to the Y-axis, and on each surface of the piezoelectric material 35 perpendicular to the Y-axis. Extraction element: □ Bimorph type oscillator 39 by joining the element 38
Configure.

Such a bimorph type vibrator 39, as shown in the plan view in FIG. 3 to form a vibrating structure 4 including a driving vibrator 28 and an extraction element 38.

Here, one electrode 30 of each drive vibrator 28 that is not divided is grounded, while each divided electrode 31A, 3
1B, variable resistors 32A, 32B, 32C, 32D
, one electrode 36 of the extraction element 38 is connected to the oscillator 33 through the
It can be made to function in the same manner as shown in FIG.
, 32B, 32C, and 32D, the vibration of each bimorph vibrator 39 in the Y-axis direction is fed back to the oscillator 33 by the extraction element 38, thereby generating a bimorph vibrator. 39 vibration amplitudes, etc. can be controlled.

Thus, according to these embodiments, the offset output of the detection means 5.16 provided on the support portion of the vibrating structure 4 can be extremely effectively reduced, and a highly accurate and high-performance vibrating gyroscope can be provided.

Although the present invention has been described above based on the illustrated examples, the present invention is also applicable to a vibrating gyroscope having another structure, such as a vibrating gyroscope having a conventional structure as shown in FIG. It can also be applied to a vibrating gyroscope having a structure in which the vibrating structure 4 shown in FIG. An X
The present invention can also be applied to a vibrating gyroscope having a structure provided with a Coriolis force detection means 40 that flexibly vibrates in the axial direction.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, when a plurality of drive vibrators are bonded to the negative arm member by bonding a single drive vibrator to each arm member, Therefore, the drive vibrator can be easily and efficiently attached to the arm member without causing a decrease in the positional accuracy of the transducers, and without the risk of expanding the lateral vibration of the arm member. can be attached.

Moreover, by appropriately adjusting the voltage applied to the divided electrodes of the drive vibrator, the offset output of the detection means can be adjusted to
Extremely effective reduction without being affected by environmental temperature,
A high-performance vibration gyroscope with high detection accuracy can be provided.

[Brief explanation of the drawing]

FIG. 1 is a perspective view illustrating a driving vibrator which is a main part of the present invention; FIG. 2 is a plan view showing an application example of the driving vibrator shown in FIG. 1 together with an electric circuit; The figure is a perspective view showing another example of the drive vibrator, □r+
7. FIG. 4 is a plan view showing an application example similar to FIG. 2, FIG. 5 is a perspective view showing a bimorph vibrator equipped with a driving vibrator, and FIG. 6 is also similar to FIG. 2. 7 is a perspective view illustrating a vibrating gyroscope with another structure to which the present invention can be applied; FIG. 8 is a perspective view illustrating a conventional vibrating gyroscope; FIG. 9 is a perspective view illustrating a conventional vibrating gyroscope; Fig. 10 is a perspective view showing a vibrating gyroscope to which the present invention can be applied, as previously proposed by the applicant; Fig. 11 is a front view showing the influence of unbalance of both arm members; Figs. 12 and 13. 2A and 2B are plan views illustrating causes of lateral vibration of the arm member, respectively. 1.2... Arm member, 3-... Base portion, 4... Vibration structure, 5, 1 Row... Detection means, 28... Drive vibrator, 29... Piezoelectric material, 30. 31... Electrode, 31A, 31B, 31C... Divided electrode, 32
A, 32B, 32C, 32D --- variable resistor, 33
... Oscillator, 34... Thin plate, 35... Piezoelectric material, 36, 37... Electrode, 38... Extraction element, 3
9... Bimorph type resonator, 40... Detection means

Claims (1)

[Claims] 1. Extending parallel to each other in the Z-axis direction of the three-dimensional coordinate system
Two arm members located at intervals in the axial direction, a base portion interconnecting these arm members at one end of each, and each arm member provided on a surface perpendicular to the Y axis. A vibrating gyroscope comprising a driving vibrator and a detection means for detecting the Coriolis force generated in each arm member and acting in the X-axis direction, wherein each of the driving vibrators is made of a single piezoelectric material. A vibrating gyroscope constructed by providing electrodes on each plane perpendicular to the Y-axis and dividing at least one of these electrodes in the X-axis direction, so that the voltage applied to the divided electrodes can be freely adjusted.