JPH0926322A - Angular-velocity detection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an angular-velocity detection apparatus by which an angular- velocity detection value is obtained with high accuracy and whose assembling operation is performed easily. SOLUTION: A driving signal is input between a pedestal 200 and a diaphragm 201, and it is applied across piezoelectric elements 202a, 202b, for driving, which are arranged between them and which comprise a thickness slip vibration mode so as to be vibrtaed. The piezoelectric elements are vibrated in directions in which the surface on the side of the pedestal 200 at the piezoelectric elements 202a, 202b for driving and the surface on the side of the diaphragm 201 are the X-axis direction and which are different by 180 deg.. The diaphragm 201 is turned repeatedly and vibrated at a fine angle on X-plane and Y-plane by taking a part near the center of gravity of the disphragm 201 as the center. Piezoelectric elements 203a to 203d, for angular- velocity detection, which are bonded to the part of a vibrating arm, are vibrated repeatedly with reference to the direction of a rotation. When an angular velocity ωis applied during their vibration, Coriolis' force acts on the diaphragm 201, the vibrating arm is bent, Coriolis' force is detected from detection signals which are output by the piezoelectric elements 203a to 203d for angular-velocity detection, it is computed and processed, and the angular velocity ω is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity detecting device for use in a car navigation system or the like for detecting the angular velocity of a moving body (vehicle) mounted on the vehicle.

[0002]

2. Description of the Related Art Conventionally, a vibration type angular velocity detecting device is a tuning fork or a complicated structure, and a highly accurate one is used.

FIG. 3 is a perspective view showing the structure of such a conventional angular velocity detecting device. In FIG. 3, this example is
The pedestal 100 is fixed with a support rod 102. The tuning fork type vibrator 104 includes two driving vibrators 104a and 10a.
4b are joined by sandwiching the base block 103, and further,
The detection oscillators 106a and 106b are connected to the drive oscillator 104.
They are arranged on top of a and 104b and shifted by 90 degrees. Driving piezoelectric elements 105a and 105b are attached to the driving vibrators 104a and 104b. In addition, the detection piezoelectric element 10 is attached to the detection vibrators 106a and 106b.
7a and 107b are attached. Driving piezoelectric elements 105a and 105b and detection piezoelectric elements 107a and 10
7b are terminals 101a, 101b and 101, respectively.
It is connected to c, 101d, 101e and 101f by a connection line not shown. Terminals 101a to 101f are pedestal 10
It projects from the lower part of 0 and is connected to an external circuit board (not shown). The driving piezoelectric elements 105a and 105b are driven by the driving signals supplied to the two terminals 101a to 101f.
Are excited to vibrate the driving vibrators 104a and 104b.

The operation of the angular velocity detecting device constructed as above will be described below.

FIG. 4 is a perspective view showing an operating state of the driving vibrators 104a and 104b. In FIG. 4, the driving vibrators 104a and 104b vibrate toward and away from the central axis P. As a result, the detection oscillators 106a and 106b also vibrate toward and away from the central axis P. When this device rotates at an angular velocity ω during this vibration, the Coriolis force is generated in the direction perpendicular to the member planes of the detection vibrators 106a and 106b as shown by the following equation (1).

F = 2 mvω (1) The detection oscillators 106 a and 106 are generated by this Coriolis force.
b will bend in a direction perpendicular to the plane of this member. Due to this deflection, the detection vibrators 106a and 106a
Electric charges are generated in the detecting piezoelectric elements 107a and 107b on the line b, and signal processing is performed on the output of the electric charges.

FIG. 5 is a block diagram showing a signal processing circuit for performing such signal processing. In FIG. 5, the charges of the detection piezoelectric elements 107a and 107b are changed to the charge amplifier 15
0 is amplified and converted into a voltage change, and the synchronous detection circuit 151
The excitation signal component is removed by, and the offset adjustment circuit 152, the level adjustment circuit 153, and the low-pass filter (L
PF) 154 to remove unnecessary signal components, and
The angular velocity ω can be obtained by adjusting the output sensitivity to the specified value. Further, the excitation vibration detection charge amplifier 155
Detects the vibration of the driven tuning fork portion from one of the driving piezoelectric elements 105a and 105b, and generates a constant level drive signal by an AGC (automatic gain adjustment circuit) 156,
Through the drive circuit 157, the driving piezoelectric element 105
It is output to the other of a and 105b. That is, the vibration is held constant by feedback control.

[0008]

However, in the angular velocity detection device of the conventional example, the driving vibrators 104a, 104 are used.
If b and the transducers for detection 106a and 106b are not arranged at accurate vertical positions, correct detection values cannot be obtained, and therefore highly accurate arrangement (assembly) is required. Further, in the case of the tuning fork type, the driving frequency is determined by the mechanical resonance frequency, and therefore, trimming for setting the frequency is required after assembly. That is, the conventional angular velocity detection device has the drawbacks that it is difficult to obtain a highly accurate detection value, and that assembly is time-consuming and costly.

The present invention solves the above-mentioned conventional problems, and it is possible to reliably obtain a highly accurate detected value, and
It is an object of the present invention to provide an excellent angular velocity detection device that facilitates assembly work and enables cost reduction.

[0010]

In order to achieve the above object, an angular velocity detecting device according to claim 1 has a thickness-sliding vibration mode between a pedestal and a diaphragm, and a pedestal-side vibration mode is generated by a drive signal. The surface and the surface on the diaphragm side are in the X-axis direction and 18
Driving elements that vibrate in directions different from each other by 0 degrees are joined and arranged, and at least one set of angular velocity detecting elements is joined and arranged on a vibrating arm that is provided with the center of the diaphragm symmetric. In addition, the drive signal supplied to the pedestal and the diaphragm causes the angular velocity detecting element to repeatedly rotate about the center of gravity of the diaphragm by an angle on the XY plane and vibrate. The vibrating arm is bent by the action of the Coriolis force when an angular velocity is applied, and the angular velocity detecting element outputs a detection signal corresponding to this Coriolis force.

According to a second aspect of the present invention, there is provided an angular velocity detecting device in which piezoelectric elements are used as the driving element and the angular velocity detecting element.

[0012]

With such a structure, in the angular velocity detecting device according to the first and second aspects, the driving element, for example, the driving piezoelectric element vibrates in response to the driving signal supplied to the pedestal and the vibration plate. Further, the angular velocity detecting element, for example, the angular velocity detecting piezoelectric element, repeatedly rotates about the center of gravity of the diaphragm and vibrates at an angle on the XY plane. The vibrating arm bends due to the action of the Coriolis force when an angular velocity is applied during this vibration,
The angular velocity detecting element outputs a detection signal corresponding to the Coriolis force. That is, the vibrating body vibrates in the direction perpendicular to the Coriolis force generation direction, and the troublesome and highly accurate assembly work for accurately arranging the driving vibrator and the detecting vibrator as described above is not required. . In addition, the frequency of the drive signal depends only on the driving element and is not affected by the mechanical resonance of the diaphragm, so the drive frequency is no longer determined by the mechanical resonance frequency as described above, and the frequency adjustment There is no need for trimming. Therefore,
A highly accurate detected value can be reliably obtained, and the assembling work becomes easy.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an angular velocity detecting device of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a perspective view showing the configuration of an embodiment of the angular velocity detecting device of the present invention. In FIG. 1, in this example, driving piezoelectric elements 202a and 202b having a thickness-shear vibration mode are joined and arranged between a pedestal 200 and a diaphragm 201. A drive signal is supplied from a drive circuit (not shown) between the base 200 and the diaphragm 201, and this input drive signal is applied to each of the drive piezoelectric elements 202a and 202b. Also, the angular velocity detecting piezoelectric elements 203a, 203b, 203c, 203d
Are joined to the vibrating arms of the vibrating plate 201, respectively, and perform repetitive vibration (repetitive motion) in the rotation direction.

Next, the operation of this embodiment will be described. FIG. 2 is a diagram for explaining an operating state of the configuration shown in FIG. 1 and 2, when a drive signal is supplied between the pedestal 200 and the diaphragm 201, this input drive signal is applied to each of the drive piezoelectric elements 202a and 202b, and the drive signal is applied by applying this input drive signal. The piezoelectric elements 202a and 202b vibrate. This vibration vibrates in the X-axis direction and in a direction different by 180 degrees between the surface of the drive piezoelectric elements 202a and 202b on the base 200 side and the surface of the vibration plate 201 side. The vibrating plate 201 is repeatedly rotated about the center of gravity of the plate around the center of gravity of the plate on the XY plane at a delicate angle and vibrates as shown in FIGS. Also, the angular velocity detecting piezoelectric element 203 joined to the vibrating arm portion of the vibrating plate 201.
a to 203d perform repetitive vibration in the rotation direction. Due to this repetitive vibration, the angular velocity detecting piezoelectric elements 203a, 2a
03d vibrate with respect to the center line of the diaphragm 201 in the Y-axis direction so that if the angular velocity detecting piezoelectric element 203a is separated, the angular velocity detecting piezoelectric element 203d is also separated, as shown in FIG. 2A. Further, as shown in FIG. 2B, when the angular velocity detecting piezoelectric element 203a approaches, the angular velocity detecting piezoelectric element 203d also vibrates so as to approach. Similarly, the angular velocity detecting piezoelectric elements 203b and 203c are also separated from the center line of the diaphragm 201 in the Y-axis direction as shown in FIG. 203c also vibrates away. Then, as shown in FIG. 2A, the angular velocity detecting piezoelectric element 20
When 3b approaches, the angular velocity detecting piezoelectric element 203c also vibrates so as to approach.

Piezoelectric element 203a for detecting angular velocity in this portion
When the angular velocity ω is applied during the vibration of ~ 203d, the vibration plate 20
Coriolis force acts on 1 and the vibrating arm bends. That is,
It becomes possible to detect the Coriolis force from the detection signals of the angular velocity detecting piezoelectric elements 203a to 203d, and the angular velocity ω is detected with high accuracy by calculating the detection signal.

In this embodiment, one vibrating arm is provided for each vibrating plate 201. However, a plurality of vibrating plates 201 are provided and an angular velocity detecting piezoelectric element is arranged to detect the Coriolis force with high sensitivity. You can also do it.

[0018]

As is apparent from the above description, according to the angular velocity detecting device of the first and second aspects, the driving piezoelectric element is vibrated by the driving signal supplied to the pedestal and the diaphragm, and the angular velocity is increased. The detecting piezoelectric element repeatedly rotates about the center of gravity of the vibration plate and vibrates at an angle on the XY plane. The vibrating arm is bent by the action of the Coriolis force when an angular velocity is applied during this vibration, and the angular velocity detection element outputs a detection signal corresponding to the Coriolis force. That is, the vibrating body vibrates in the direction perpendicular to the Coriolis force generation direction, its accurate arrangement is no longer required, and the frequency of the drive signal depends only on the driving element and is not affected by the mechanical resonance of the diaphragm. For,
Trimming for adjustment is not necessary, highly accurate detection values can be reliably obtained, and the assembly work is facilitated, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration in an embodiment of an angular velocity detecting device of the present invention.

FIG. 2 is a plan view showing an operating state of the configuration shown in FIG. 1, FIG. 2 (a) is a plan view showing an operating state in which an angular velocity detecting piezoelectric element is separated, and FIG. 2 (b) is a plan view showing an operating state in which an angular velocity detecting piezoelectric element is approaching.

FIG. 3 is a perspective view showing a configuration of a conventional angular velocity detection device.

FIG. 4 is a perspective view showing an operating state of the conventional example shown in FIG.

FIG. 5 is a block diagram showing a signal processing circuit in a conventional example.

[Explanation of symbols]

 200 pedestal 201 diaphragm 202a, 202b driving piezoelectric element 203a-203d angular velocity detecting piezoelectric element

Claims (2)

[Claims] 1. A driving device having a thickness-shear vibration mode between a pedestal and a diaphragm, and a pedestal-side surface and a diaphragm-side surface vibrating in directions different from each other in the X-axis direction and 180 degrees by a drive signal. At least one set of angular velocity detecting elements are arranged so as to be joined to an oscillating arm that is arranged such that the elements are joined together and the center of the diaphragm is symmetrical, and is supplied to the pedestal and the diaphragm. The drive signal generated causes the angular velocity detecting element to move the X-axis centering around the center of gravity of the diaphragm.
While vibrating by repeatedly rotating at an angle on the Y plane, the vibrating arm is deflected by the action of the Coriolis force when an angular velocity is applied during this vibration, and the angular velocity detecting element outputs a detection signal corresponding to this Coriolis force. An angular velocity detection device characterized by: 2. The angular velocity detecting device according to claim 1, wherein a piezoelectric element is used as the driving element and the angular velocity detecting element.