JPS63285412A - Gyroscopic apparatus - Google Patents

Abstract

PURPOSE:To obtain a high performance gyroscope with the equalization of vibration turbulence, by turning a vibration mode of a cylindrical vibrator. CONSTITUTION:A cylindrical vibrator 13 is supported with supports 12a and 12b fixed on a case 11, driving elements 14a-14h are arranged on the vibrator 13 to drive, and then, the vibrator 13 is driven radially with driving circuit 31a and 31b while turning the vibration mode thereof circumferentially. When an angular velocity acts on a gyroscopic apparatus in the Z-Z axis of the cylindrical vibrator 13, turning angular velocity of the vibration mode of the vibrator 13 changes according to the angular velocity inputted. So, this change in the speed is measured by a computing section 16 from a time difference between displacement detectors 15, and moreover, the computing section 16 detects the max. phase advance angle of a mode turning angle. To maintain the phase advance angle, a driving system of the vibrator 13 is controlled and the angular velocity and an angle are computed from a phase difference detected as mentioned above.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gyro device, particularly a vibration type gyro device.

[Conventional technology]

Although the present invention is different in principle from various types of gyros conventionally used, a vibrating gyro whose principles and structure are relatively similar to the present invention will be explained with reference to FIG. 6 as a conventional example. . In the example shown in the figure, the tuning fork (1) is
Attach to the base (2) via the flexible shaft (31). Tuning fork (1
), install the displacement detector @ (6) and the drive coil (4), input the output of the displacement detector (6) to the drive coil (4) through the drive amplifier (5), and connect the tuning fork (
1) The vibration amplitude is kept constant.

When the angular velocity Ω is input around the axis (Z - Z) of the deflection axis (3) of the tuning fork (+1), the vibration J velocity of the tuning fork (1) is
Coriolis force Fc corresponding to one input angular velocity Ω is generated,
This causes the entire tuning fork (1) to alternately rotate around the axis (Z-Z). That is, torsional vibration occurs in the tuning fork (11).

In the conventional example shown in FIG. 6, this torsional vibration of the tuning fork (1) is detected by a torsion detector (8), and this detection output and the output of a drive amplifier (5) are synchronized by a demogierator (7). By rectifying the input angular velocity Ω, the input angular velocity Ω is detected and a gyro device is constructed.

[Problems to be Solved by the Invention] However, in such conventional vibrating gyro devices, the Coriolis force generated by input angular velocity acting on a vibrating body such as the tuning fork (1) is converted into angular displacement. Since this displacement is detected by torsion detection B+8), the detection sensitivity is low.

Furthermore, when a piezoelectric element or the like is used as the torsion detector (81), the temperature has a large effect on the detection sensitivity.In addition, the unbalance of the tuning fork (1) itself is due to the A tuning fork (
1) It requires precise balancing and has many drawbacks, such as requiring a lot of time for balance adjustment.

Therefore, it is an object of the present invention to provide a new gyro device that eliminates the drawbacks of the conventional gyro device described above.

[Means for solving problems]

The gyro device according to the present invention supports a cylindrical vibrating body (13) by supports (12a) and (12b) fixed to an outer casing (11), and the vibrating body has a swing body for driving one body. The drive elements (14a) to (14h) are arranged, and the drive circuits (31a) and (31b)
The vibrating body is driven in the radial direction and also in the circumferential direction so that the vibration mode rotates. Also, the vibration body (
Z-Z) A detection element (15) for detecting the radial displacement of the end in the axial direction is installed in the outer casing, and its output is supplied to the calculation unit (16).

[Effect]

When an angular velocity acts on the above-mentioned gyro device of the present invention in the (Z-Z) axis direction of the cylindrical vibrating body (13), the turning angular velocity of the vibration mode of the vibrating body changes depending on the input angular velocity. Detect each displacement! (15) The maximum phase advance angle of the mode turning angle is detected, and in order to maintain this phase advance angle, the drive system of the vibrating body is controlled, and the angular velocity and Calculate angle.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 shows a vibrating section (
10) is a partially cutaway perspective view showing the inside thereof, and a wiring diagram of the circuit elements of the arithmetic unit (16) that performs drive, displacement detection, drive control, etc. of the vibrating unit (10). Vibrating part (l
O) is mainly composed of an outer casing (11) and a vibrating body (13) disposed inside the outer casing (11). The outer casing (11) is a cylindrical container whose openings at both ends are sealed so that the inside is almost vacuum. They are arranged so that the longitudinal axes, in other words, the central axes (2-Z), coincide with each other. (2
-Z) axis, and the longitudinal direction of the outer casing (11) and the vibrating body (13) are along one common diameter of the vibrating body (13).
13) A pair of supports (12a) and (12b) are arranged approximately at the center in the (Z-Z) axis direction between them as follows. That is, both supports (12a), (1
2b) is fixed to the inner peripheral surface of the cylindrical outer casing (11), and the inner end is fixed to the outer peripheral surface of the cylindrical vibrating body (13).

Therefore, the vibrating body (13) is supported by both supports (12a) and (12b) in the cylindrical outer casing (11) so that it can freely vibrate (deform) as described below. .

The cylindrical vibrating body (13) is made of, for example, a metal such as a constant elastic material, and the wall thickness of the cylindrical portion is substantially uniform. Further, on the outer circumferential surface of the central part of the vibrating body (13), for example, eight piezoelectric elements (14a) to 8 are arranged at equal intervals on the same circumference.
(14h) is glued.

For example, eight capacitive displacement detectors are installed at one end of the vibrating body (13) in the (Z-Z) axis direction, in the example shown in FIG. 1, facing the outer peripheral surface of the upper end with a gap. (15) are fixed to the inner peripheral surface of the outer casing (11) at equal intervals, and are structured to detect displacement of the vibrating body (13).

In addition, the eight piezoelectric elements (14a) to (14h
) and the eight displacement detectors (15) are both connected to the calculation unit (16
), and is configured to detect the drive and displacement of the vibrating body (13) and perform angle or angular velocity control.

The driving of the vibrating body (work 3) will be explained using FIG. 2. FIG. 2 is a side view of the vibrating body (13) where CZ-Z>W at the center in the axial direction and a wiring diagram of the drive circuits (31a) and (31b) of the piezoelectric elements (14a) to (14h). As shown in the figure, piezoelectric elements (14a) to (14
b), there are eight second
They are bonded in the direction of the polarization axis shown in the figure.

And 4 (lAl piezoelectric elements (14a)) every 90°
, (14c)(14e), (14g
) are connected to the output side of the drive circuit (31b), and the piezoelectric elements (14b) and (14b) adjacent to the piezoelectric element are
14d), (14f), and (14h) are connected to the output side of the drive circuit (31a), and both drive circuits (31
The signal phase difference between the outputs of a) and (31b) is 9
It is 0゛. In this way, B: type element (14a) ~
When each piezoelectric element (14a) to (14h) is driven with a signal having a phase difference of 90° from the adjacent piezoelectric element at a driving position rotated by 45°, the input 4m of (14h) is not all the same, and the third
As shown in the figure, the vibration mode of the oscillatory body (13) rotates at 1/2 of the angular velocity ω of the drive power source.

Figure 3 shows the vibration mode at the <Z - Z) axial end of the vibrating body (13). Figure A shows the vibration mode when ωt=Q, and Figure 3 shows the vibration mode when ω is equal to π. /2, same figure C
represent the vibration modes at ωt−π, respectively.

In Figure 3, for a 'W3 car, there is a -shaft and a 45mm
Although the illustration shows that voltage is applied to positions forming an angle of
This is the deformation mode of the vibrating body (13) driven in 4a) to (14h). As is clear from FIG. 3, by using this drive method, the vibration mode of the vibrating body (13) can be easily rotated. The overall vibration mode of the vibrating body (13) at this time is as shown in FIG.
3) The vibration modes of both end faces in the (Z-Z) axis direction are in phase, and the overall shape is an elliptical serpentine shape. Therefore, the center of the vibrating body 13) in the (Z-Z) axis direction is a vibration node. Therefore, if this point is supported, the influence of the support on the vibration mode can be removed, so the pillars (12a) and (12b) are
As mentioned above, it is desirable to arrange it at the vibration node of the vibrating body (13). Consider a case where an angular velocity Q acts in the (Z-Z) axis direction of the vibrating body (13) during the rotation of the vibration mode of the vibrating body (13).

Figure 5 shows the mode rotation when the angular velocity Ω acts on the gyro when viewed from the coordinate system that rotates at the angular velocity ω/2 while the vibrating body (13〉) is rotating at the angular velocity ω/2. In the case of Ω-〇 In , the peak position of the amplitude of the vibrating body (13) at a certain moment is, when the angular velocity acts on the gyro in the same direction as the mode rotation direction, the peak position of the amplitude advances only when the angular velocity acts, and in the opposite direction. When angular velocity acts, there is a delay only when angular velocity acts.The maximum value of the phase lead (or lag) angle at this peak position is proportional to the input angular velocity Ω, so by detecting this maximum phase angle, you can know the input angular velocity. be able to.

One end of the angular velocity or angle input to the actual gyro is
As shown in Fig. 1, eight capacitive type sensors are installed at equal angles in order to detect the displacement of the end of the vibrating body (13) in the (Z-Z) axis direction. The displacement detector (15) is driven by a power supply (18), and the output thereof is converted into a voltage value in a displacement detection circuit (17) consisting of a bridge circuit, a filter circuit, etc. Since the displacement output voltage seen by each displacement detector (15) during the rotation of the vibration mode of the vibrating body (13) is chemotactic in a sinusoidal manner, the peak detection circuit (19) detects the ) is differentiated, and the peak time of vibration of the vibrating body (13) is detected from the voltage output from the displacement detection circuit (17) at the zero-crossing of the rising signal of the differential value. The displacement voltage at this peak time is held by a peak hold circuit (20) and used as a displacement for @width control, which will be described later.

On the other hand, the peak time detected by the peak detection circuit (19) is supplied to the peak cycle hand side circuit (21). At this time, the counter counts the reference clock based on the output of the peak detection circuit (19), and
The time at which the peak passes through the position of each displacement detector (15) is measured. Therefore, in this method, the first
A displacement detection circuit (17) shown in the dashed line block in the figure,
Peak detection circuit (19), peak hold circuit (20)
) and peak cycle measuring circuits (21) are required as many groups as there are displacement detectors (15), although not shown in the figure.
In the example shown in the figure, there are 8 channels of moromi and kana. The peak passing time interval of the vibrating body (13) measured by the peak period measuring circuit (21) is inputted to the phase difference calculating section (26) for all channels. Phase difference calculation section (
In 26), when no angular velocity is input in the input axis direction of the gyro, the mode turning angular velocity of the vibrating body (13) is
It is determined by the reference frequency from the reference frequency generator (29) and is constant. Therefore, adjacent displacement detectors (15
) The peak time of the vibrating body (13) passing between the two regions becomes constant. However, when the angular velocity Ω is input in the direction of the input axis of the gyro, that is, the (Z-Z) axis, the peak turning velocity of the vibrating body (13) is as shown in Fig. 5. It changes only between. The tip position of this changed peak is determined by successively comparing the times during which the peak passes through each displacement detector (15). In this way, it is possible to detect the phase difference of the peak of the vibrating body (13) seen from the sewn yarn rotating at the mode rotation angular velocity with respect to when no angular velocity is input. The part that performs this calculation is a phase difference calculation unit (26).

Since the maximum value of the phase difference is proportional to the input angular velocity, the angular velocity calculation section (32) applies a scale factor determined by the moment of inertia of the vibrating body (13) to the phase difference from the phase difference calculation section (26). By shifting, the input angular velocity Ω can be obtained.

Further, the shark-sized phase difference obtained by the phase difference calculation section (26) is added to the phase difference one time before in the phase addition section (27). Then, the bigonal function generator (28) uses the phase difference value φ obtained by the phase difference adder (27) to calculate As1n (ωt+φ).

A function Acos (ωt+φ) is generated. Here, A is the drive amplitude of the vibrating body (13), which is determined by a vibrating body amplitude control circuit, which will be described later. Also, ω is the vibrating body (1
3) is the vibration reference angular frequency of the reference frequency generator (2).
9). The output of this trigonometric function generator (28) is converted into D/A converter 3B (30a), (30b)
After D/A conversion, the piezoelectric elements (14a) to (14
The piezoelectric elements (14a) to (14h) are driven through drive circuits (31a) and (31b) consisting of current amplification and bypass filters for driving the piezoelectric elements (14a) to (14h).

When the angular velocity detection system is configured in this way, the mode turning angular velocity of the vibrating body (13) changes depending on the input angular velocity,
This can be regarded as a change in phase angle, and the phase angle obtained by integrating the change values of this phase angle is proportional to the angle input around the input axis of the gyro. Therefore, in the angle calculation section (33), the input angle can be obtained by multiplying the phase difference obtained by the phase difference addition section (27) by a scale factor.

In this way, the rotation angle input to the gyro is changed to the vibrating body (1
3) The point that the phase difference of the mode turning can be detected as the phase difference at the original position of the vibration mode turning angle and the measured phase difference is returned to the drive system to measure the phase difference of the mode turning as an integral value is the present invention. This is a feature of the gyro device.

On the other hand, the drive system of the vibrating body (13) is affected by changes in internal damping and Young's modulus of the vibrating body (13) due to changes in ambient temperature, damping due to gas molecules in the outer casing (11), etc.
3) The vibration mode of the vibrating body changes due to disturbances caused by non-uniform changes in manufacturing. Due to this, the time difference in which the peak of the vibrating body (13) passes through each displacement detector (15) changes, and this time difference directly becomes a detection error. Therefore, in the embodiment of the present invention, where it is necessary to control the vibration mode so that it is always constant, the height of the peak of the vibrating body (13) obtained by the peak hold circuit (20) described above is calculated using a computer ( 16'), the switch (22) switches, the output of each displacement detection 'a (15) is A/D converted by the A/D converter (23), and the average value calculation section (24) The average value of the peak amplitude of the vibrating body (13) is determined. This average value is compared with a reference amplitude from a reference amplitude source (25) by a comparator (25'), and based on the comparison result, the amplitude value of the trigonometric function generator (28) is determined. By constructing such a control loop, the peak amplitude value of the vibrating body (13) is controlled so as to always match the reference amplitude.

By configuring the gyro device as described above, a highly accurate gyro can be obtained with a simple configuration.

In addition, in FIG. 1, the wall thickness of the cylindrical part of the vibrating body (13) is uniform, but it may be non-uniform in the (Z-Z) axis direction of the vibrating body (13). The vibration mode in the (Z-Z) axis direction of the vibrating body (■3) was configured to be symmetrical with respect to the center in the (Z-Z) axis direction, but the piezoelectric element (1
By providing sets of 4a) to (14b) at the upper and lower parts of the (Z-Z) axis direction, respectively, and making the polarities opposite to each other,
The vibrating body (13) may be separately moved by one rotation with a phase difference of 180 degrees in the upper and lower parts of the vibrating body (13) in the (Z-Z) axis direction.

[Effect of the invention] Since the vibration mode of the cylindrical vibrating body is rotated, vibration disturbances caused by non-uniformity of the vibrating body can be averaged.
A high-performance gyro can be obtained. Also, since the structure is @car,
A high-performance gyro can be obtained at a low cost. Unlike a gyro with a rotating body, there are no wear parts such as ball bearings, so it is possible to manufacture a gyro that is highly reliable and has a long life.

Historically, since the detection system does not use elements with large temperature fluctuations such as piezoelectric elements, it is possible to obtain a gyro with excellent temperature characteristics. Furthermore, by processing the output of the displacement detector, not only the angular velocity signal but also the angle signal can be output.

[Brief explanation of the drawing]

Fig. 1 is a route map of an embodiment of the present invention, Fig. 2 is a sectional view of the central part of the vibrating body including the drive section, and Fig. 3 is a diagram of the vibration mode of a cross section perpendicular to the input axis of the vibrating body. , FIG. 4 is a diagram of the vibration mode of the vibrating body seen from the side, FIG. 5 is a diagram of the vibration mode of the vibrating body when there is an angular velocity input, and FIG. 6 is a perspective view of a conventional vibrating gyroscope. In the figure, (10) is the vibrating part, (11) is the outer casing, and (12) is the vibrating part.
a), (12b) are supports, (13) are vibrating bodies, (14a) to (14h) are piezoelectric elements, (15
) indicates a displacement detector, (16) a calculation unit, and (16') a calculator, respectively.

Claims (1)

[Claims] 1. An outer casing, a cylindrical vibrating body disposed within the outer casing,
a support whose both ends are fixed to the outer casing and the vibrating body;
a driving element provided on the vibrating body so as to give vibration in the radial direction to the vibrating body and to rotate a vibration mode of the vibrating body in the circumferential direction; a driving circuit that drives the driving element; and the outer casing. a detector that detects the radial displacement of the vibrating body relative to the radial direction; and a detector that receives the output signal from the detector as input, detects a change in the rotational angular velocity of the vibration mode of the vibrating body, and detects the rotation phase angle of the vibration mode of the vibrating body. A gyro device comprising: a calculation unit that calculates the input angle or angular velocity by adding the input angle or angular velocity to the phase of the previous time. 2. The gyro device according to claim 1 is characterized in that the cylindrical vibrating body is supported by its vibration nodes.