JPS58221109A - Gyro device - Google Patents

Abstract

PURPOSE:To improve the sensitivity of detection with simple constitution and to eliminate the influence of an external acceleration, by mounting two flat plates having inertial mass symmetrically orthogonally with a shaft which oscillates alternately, and drawing out differentially the axial displacement of the flat plates generated by Coriolis forces. CONSTITUTION:Thin platelike members 13, 13' having a weight 14 are mounted symmetrically to a shaft 11, and a driving device 16 is driven by the output of a driving amplifier 5 to oscillate the plates 13, 13' alternately at an angular speed omega. When the weights 14, 14' move in opposite directions at a velocity (v), an angular speed OMEGA is inputted around an axis X and the upward and downward Coriolis forces FC act on the weights. The rates of deflection in the opposite directions at the forward ends of the plates 13, 13' which are generated as a result of said action are detected with a displacement detector 17, whereby the input angular speed OMEGA is detected. Since the Coriolis forces are detected as the direct displacement, the sensitivity of detection is high and since the thin plates are used as a sensing part, the influence of the external acceleration in the axial direction of the oscillation is eliminated and the construction is made simple and rigid.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gyro device, particularly a frequency gyro device.

Conventionally, as this type of vibrating gyro device, one shown in FIG. 1, for example, has been provided.

In the conventional gyro device shown in FIG. 1, the tuning fork 11)
is attached to the base (2) via the flexible shaft (3). A displacement detector (6) and a drive coil (4) are installed near the upper end of the tuning fork (1), and the output of the displacement detector (6) is passed through a drive amplifier (5) to the drive coil (4). I input it and keep the vibration amplitude of tuning fork +11 constant. When an angular velocity Ω is input around the axis (2-2) of the deflection axis (3) of the tuning fork (11), a Coriolis force Fc corresponding to the vibration velocity v1 of the tuning fork (1) and the human force angular velocity Ω is generated. , thereby causing the entire tuning fork (1) to alternately rotate around the axis (2-2).

That is, torsional vibration occurs in the tuning fork fil.

In the conventional example shown in FIG. 1, this torsional vibration of the tuning fork (1) is detected by a torsion detector (8), and the detected output and the output of the drive amplifier (5) are combined by a demosulator (7). The input angular velocity Ω is detected by synchronous rectification.

However, in such conventional vibrating gyro devices, the Coriolis force Fc corresponding to the input angular velocity Ω is extracted as a tuning fork (130 rotation angle) having a large moment of inertia, so the sensitivity to the input angular velocity Ω is poor ( ,
If you try to increase this, the entire device will become a large building, and the unbalance of the tuning fork [11] will directly affect the detection accuracy, so the requirements for processing accuracy will be strict, so this should be avoided. If the driving frequency of the tuning fork (1) is lowered, the disturbance due to the imbalance of the tuning fork (1) will increase, the frequency characteristics will decrease, and since the tuning fork (11) is supported in a cantilevered manner, the bending axis (3) will be lowered. ) has to have a large load capacity, which has the problem (disadvantage) of increasing the size of this part.

Therefore, the main purpose of the present invention is to focus on the problems (defects) of such conventional devices, and to install two flat plates having an inertial mass at positions 1800 degrees symmetrical about the axis of alternating vibration. To provide a gyro device which solves the above problems by installing the two flat plates so that their surfaces are perpendicular to the axis and differentially extracting the axial displacement or distortion of the two flat plates caused by the Coriolis force. is in

Therefore, the gist of the present invention is to provide a base, a shaft member rotatably attached to the base, and a surface that is substantially perpendicular to the axis of the shaft member, and whose respective longitudinal directions are aligned. two strip-shaped members attached to the shaft member so as to be axially symmetrical with respect to the axis; a detection device that differentially detects deflection of the two strip-shaped members in the axial direction; The gyro device comprises a drive device for applying alternating angular vibration (torsional vibration) around the axis to the base to the shaft member having a strip-shaped member.

Hereinafter, the present invention having the above-mentioned gist will be explained based on the drawings.

FIG. 2 is a diagram showing an embodiment of a gyro device according to the present invention. In the example shown in FIG. 2, one end of the axis αυ is attached to the base OI so that the axis αυ is approximately perpendicular to the base OI (rotationally attached), and the other end is attached via the attachment member 0. Two, e.g., strip-shaped thin plate members C13J and am are attached. In this case, the plate member 03° (Ij is a member whose plate surface is approximately perpendicular to the axis (2-2) of the axis αυ). , and their longitudinal directions are symmetrical with respect to the axis tiυ. Weights (141, (141) are attached to the free ends of the plate members (131, ai, respectively. Q9
and a drive device (161) are attached around the axial circle, and the drive device ae is driven by the output from the external drive amplifier (5), and the mounting member α2, the plate member (13, a: 4 and the heavy The weights (141, (141) are alternately vibrated around the axis (2-2) in the figure at an angular velocity ω.Displacement detector (17)
, αh are placed on the base 01, and the weights Q41 and a4 are provided below the weights ■.

Detects the displacement in the axis (2-2) direction with respect to the base (11) of the 0 stone.Due to design considerations, the weight circle, Q41
is a plate member 0. It can also be replaced by the weight of αj itself.

Next, the operation of the embodiment of the present invention shown in FIG. 2 will be explained. Now, when the weights I and (141) are moving in mutually opposite directions at a speed V, the driving device ue causes the weights I and (141 to move around the axis (X) perpendicular to the axis (2-2) of the device. Assuming that the measured angular velocity Ω is input and the device is rotating in inertial space, an upward Coriolis force Fc acts on the weight I and a downward Coriolis force Fc acts on the weight 0. As a result, due to the flexibility of the plate member (1:1.a, 4), the amount of deflection ΔX in the opposite direction as shown in FIG.
: Occurs in j. Therefore, this is the displacement detector surface, (17)
After passing through a differential amplifier, the detected outputs are input to the demoscillator (7), whereby an output proportional to the input angular velocity Ω can be obtained. That is, the angular velocity Ω can be detected. In addition, the axis line (
2-2) Depending on the acceleration in the direction, the displacement detector (17)
, (17) generate displacement outputs, but since these are displacements in the same direction, they are canceled out by the differential amplifier a81 and do not become outputs.

FIG. 4 shows another embodiment of the invention. In this figure, the same members as those in FIG. 2 are designated by the same reference numerals, and the explanation thereof will be omitted. In the embodiment of FIG. 4, the second
In place of the displacement detector fRaD (17) shown in the figure, a piezoelectric element (18a) made of barium titanate, crystal, etc.
(1B'a) is used. That is, the piezoelectric element (18a)
, (18'a) are mounted on the plate members α row and aj, respectively, and the Coriolis force Fc is detected based on the bending distortion of the plate members as and ai, and the result is the same as the example in Fig. 2. It was designed to achieve a similar purpose. Therefore, although not shown, elements similar to those in the example of FIG. 2 are used.

In the example shown in FIG. 4, the piezoelectric elements (18a), (
Depending on how the differential amplifier (18'a) is connected, the differential amplifier (1a
l can be omitted.

FIG. 5 shows another embodiment of the invention. In this case as well, the same members as in FIG. 2 are given the same reference numerals, and detailed explanation thereof will be omitted. In this example, the annular member (to) and the shaft-like member 311 inside the annular member are attached to the base Ql at their lower ends. The annular member and the shaft member Ci! A flexible member made of, for example, four thin plates is placed between the annular member and the annular member.
Four pieces are arranged in the radial direction at an angular interval of 0°, and each end portion of each is fixed to the inner circumferential surface of the annular member (a) and the outer circumferential surface of the shaft-like member 01J, for example, by welding or the like. A pair of flexible members 4 on the same diameter include a driving piezoelectric element (c),
However, on the other pair of flexible members 4 on the same diameter, there is a strain detector c! made of a piezoelectric element or the like for detecting angular displacement. a, c
! 4 are attached to each other by adhesive or the like, and these are connected to the axis line (
Z-Z) Controlled to maintain constant amplitude torsional vibration. On the outer peripheral surface of the annular member (a), there is a thin strip-shaped piezoelectric element c! made of bimorph. The breasts are mounted such that their planes are perpendicular to the axis (2-2).

One output terminal of the piezoelectric element (c) and - is connected to the short-circuit wire (to)
, and an output corresponding to the input angular velocity Ω is electrically taken out from the other output terminal (5).

In this example, the piezoelectric element (c), - consisting of a bimorph is, for example, the plate member Q31, a, in the example of FIG.
4 and a displacement detection device (L?). In addition, in Figure 5, Figure 3, ! Weight I shown in Figure 4.

Although the sieve is omitted, depending on the design, it is of course possible to construct a structure in which these are attached in the same way.

FIG. 6 shows yet another embodiment of the invention. In this example, the drive piezoelectric element (C) of 1 ([1i1) is provided on one side of the pair of flexible members, the detection strain detector 041 is provided on the other side, and the Coriolis force detection means is , the displacement detector αη, (L?l shown in Fig. 3),
Further, in place of the bimorph piezoelectric elements (c) and (c) of FIG. 5, plate-like members Q31 and am similar to those shown in FIG. 2 are used.

FIG. 7 shows yet another embodiment of the invention.

In this example, a bimorph piezoelectric element (c) (251) is used as the detection part for the Cori-Olis force Fc, as in FIG. 5, but the difference is that the bimorph piezoelectric element is used in the vibration driving part.
This is different from the example in Figure 5. That is, the driving bimorph piezoelectric element 0
υ, cl+:+ and bimorph piezoelectric element 0a for detecting angle of change
, os, and the base (
At the same time, their upper ends are fixed to a disc-shaped mounting member (to), and a piezoelectric element eω, 051 for detecting Coriolis force is attached at an axially symmetrical position of this disc-shaped mounting member (to). Attach. Here, the driving bimorph piezoelectric element C (υ
, 06 are arranged so as to have a symmetrical curve with respect to the axis (2-2), so that the disc-shaped mounting member (7) can be bent around the axis (2-2). Alternating rotational vibration is applied. This torsional vibration is detected isometrically by bimorph piezoelectric cords oc and a'a for detecting displacement angle,
By forming a loop with an external drive amplifier (not shown), the amplitude is controlled to be constant at all times. In this example, a bimorph piezoelectric element C3U for driving and angle detection is used.

It is also possible to use four thin plate-like flexible members and a plate-like piezoelectric element attached to each of them instead of the zero stiffness.

FIG. 8 shows yet another embodiment of the invention. In this example, the drive bimorph piezoelectric element 81) in FIG.
Instead of C311, a torsionally vibrating piezoelectric element shown in FIG. It is glued crosswise to both sides of □. The rest is substantially the same as the example shown in FIG.

In each of the embodiments of the present invention described above, a control loop consisting of a displacement angle detector, a drive device, and a drive amplifier is used as the alternating vibration drive means, but if it is permissible in terms of performance,
It is also possible to drive the drive device directly by an alternating current power supply.

Further, it goes without saying that various means such as light, capacitance, electromagnetism, etc. can be used as means for detecting the deflection of the plate member in FIGS. 3, 6, etc.

Furthermore, it is also possible to use a cylindrical torsionally vibrating element instead of the plate-like torsionally vibrating piezoelectric element shown in FIG.

According to the present invention described above, the effects listed below can be obtained.

■ Since the structure directly extracts the Coriolis force acting on the weight as displacement or strain, the detection sensitivity is high and high frequency input angular velocities can be detected.

■ Since the alternating vibration drive unit and the Coriolis force detection system are completely independent, the vibration drive unit can be structured to be resistant to external vibrations and shocks while maintaining the sensitivity of the detection system. .

■ By constructing the Coriolis force sensing section with two thin plates and differentially outputting the displacement of each, it is possible to completely eliminate the influence of external acceleration in the direction of the vibration axis.

■ It has a simple structure, can be manufactured at low cost, and can be made robustly.

■ Unlike the tuning fork type, the distance between the Coriolis force detection unit and the alternating vibration drive unit in the drive axis direction is short (or can be almost zero), so the drive shaft bearings do not need to receive moment loads. This allows the drive shaft and bearings to be made smaller.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a well-known tuning fork vibrating gyroscope, FIG. 2 is a perspective view showing an embodiment of the present invention, FIG. 3 is a route map showing the principle of the embodiment of FIG. FIG. 8 is a perspective view showing other embodiments of the present invention, and FIG. 9 is a perspective view of the torsionally vibrating piezoelectric element of the embodiment shown in FIG. In the figure, (5) is the driving amplifier, (7) is the demosulator, the mouse is the base, (1B is the shaft, the fin is the mounting member, (13, a
: i is a plate-shaped member, (141, 04+ C weight, a51.
pa, i are angle detectors, α days are drive devices, αn, (1η
is displacement detection device, tie tt differential amplifier, (18a)
, (18'a) , (23, (2j, CB, (24
, C3υ, 6υ, O). - is a piezoelectric element, (to) is an annular member, (c) is a flexible member,
(2 fathoms, - is the strain detector, (E) is the short-circuit wire, (5) is the output terminal, (to) is the mounting member, and the connection is the torsional vibration type piezoelectric element. Figure 1, Figure 2, Figure 3) Figure 9

Claims (1)

[Claims] A base, a shaft member rotatably attached to the base, and each surface thereof coincides with a surface substantially orthogonal to the axis of the shaft member, and each longitudinal direction is axially symmetrical with respect to the axis. two strip-shaped members attached to the shaft member, a detection device that differentially detects the deflection of the two strip-shaped members in the axial direction; Alternating angular vibration (torsional vibration) on the shaft member around the above axis with respect to the above base.
A gyro device consisting of a drive device and a drive device for giving