JP3430711B2 - Angular velocity sensor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity sensor.

[0002]

2. Description of the Related Art For example, a tuning fork type angular velocity sensor is provided with a detection plate at the tip of both drive plates of a tuning fork type drive section in a direction orthogonal to the driving plates, and the angular velocity is kept constant while the drive plates are constantly driven. When added, the angular velocity is detected by the output from the detection plate which vibrates in the opposite directions in response thereto.

[0003]

A problem in the above-mentioned conventional example is a function of detecting whether or not the characteristics reach stable operation after the sensor is activated, or an attachment body of an angular velocity sensor, for example, a vehicle. As a result of a large impact such as a collision with a part of the part, the part is damaged and a normal detection operation cannot be performed. Therefore, an object of the present invention is to make it possible to detect a state in which a part of the angular velocity sensor is damaged and a normal detection operation cannot be performed.

[0004]

In order to achieve this object, the angular velocity sensor of the present invention comprises a pair of tuning fork drive plates.
And make an orthogonal relationship with the tips of each of the pair of drive plates.
A vibrating body consisting of a detection plate provided on the
Driving means provided in the driving body for driving vibration
And an angle generated in a direction orthogonal to the driving direction of the vibrating body
Detection means provided on the detection plate to obtain a velocity output
And a mechanical coupling signal resulting from mechanical coupling between the detection plate and the drive plate is detected by the detection means, and a failure determination is performed using this mechanical coupling signal.

[0005]

With the above configuration, the detection means detects the mechanical coupling signal resulting from the mechanical coupling between the detection plate and the drive plate ,
Since the failure is determined using this mechanical coupling signal, it becomes possible to detect whether or not the angular velocity sensor is in a state in which normal detection operation can be performed. Also, it is not necessary to separately provide a means for generating this mechanical coupling signal.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 denotes a case made of resin and having one end opened, and a lid 2 made of resin is attached to the opening of the case 1 to form a sealed space.

Inside the sealed space, the circuit board 3 and
A weight plate 4 made of metal is stored. That is, the support pins 5 are planted at the four inner corners of the case 1, and the weight plate 4 and the circuit board 3 are elastically supported and fixed by the support pins 5. In order to elastically support the weight plate 4, dampers 6 made of rubber are attached to the four corners, and support legs 7 made of resin are provided between the damper 6 and the circuit board 3, and the support pins 5 are provided. Has penetrated the damper 6, the support leg 7, and the circuit board 3 from below, and its tip is crushed toward the circuit board 3 side, whereby the circuit board 3 and the weight plate 4 are elastically supported and fixed. . As shown in FIG. 2, metal support pins 8 are vertically press-fitted and fixed to the weight plate 4 on the circuit board 3 side, and metal support pins 8 are horizontally supported on the support pins 8 in the horizontal direction. One end of the pin 9 is press-fitted and fixed. The diameter of the support pin 9 is as small as about one fifth of the diameter of the support pin 8, and the material is made of a metallic material having a spring property such as a piano wire.
A metal substrate 10 is fixed to the other end by soldering.

One end of metal drive plates 11 and 12 is fixed to both sides of the support pin 8 and 9 of the substrate 10, and plate-shaped piezoelectric elements 11a and 12a are fixed to the surfaces thereof. Thereby forming a tuning fork-shaped drive unit.
Further, as shown in FIG. 2, the other ends of the drive plates 11 and 12 are bent in a direction orthogonal to the piezoelectric elements 11a and 12a, and then the detection plates 13 and 14 formed by extension are plate-shaped piezoelectric elements 13a and 14a is fixed, and the detector is configured by this.

FIG. 3 shows a control circuit, in which the piezoelectric element 11a of the driving plate 11 is connected to the driver 15 by about 1VP-P, 1.5.
An alternating current signal of kHz is applied. Thereby, the drive plate 1
The tuning fork vibrations of the support pins 1 and 12 start inward and outward with respect to the support pin 9. A voltage proportional to the applied signal is induced in the piezoelectric element 12a of the drive plate 12 by the tuning fork vibration, which passes through the current amplifier 16 and the bandpass filter 17,
Signal A. This is the full wave rectifier 18, AGC
It is fed back to the driver 15 via the circuit 19,
AGC control of the drive signal is being performed. In the detection unit, when the piezoelectric elements 13a and 14a detect the angular velocity, the piezoelectric elements 13a and 14a both output an angular velocity signal of + Q, which is shown as an angular velocity signal in B and C of FIG. Is synthesized at point D in FIG. 3 and D in FIG.
The angular velocity signal is as follows. This angular velocity signal is then supplied to the charge amplifier 20, bandpass filter 21, and synchronous detection 2
2. Output from the output terminal 24 through the low pass filter 23. The signal waveforms at points E, F, and G in the meantime are shown in FIG.
E, F, and G are shown as angular velocity signals.

In the present embodiment, the drive plates 11,
Although the detection plates 13 and 14 must be provided in a direction orthogonal to the position 12, it is practically difficult to make this a true orthogonal direction, and the size of the piezoelectric elements 13a and 14a and the mounting method thereof are completely different. Since they cannot be the same, as a result, the mechanical coupling signals shown in B and C of FIG. 4 are always generated from the piezoelectric elements 13a and 14a. In this case, the piezoelectric elements 13a and 14a are attached to the same surface of the detection plates 13 and 14, and the centers of gravity of the detection plates 13 and 14 are slightly displaced to the attachment sides of the piezoelectric elements 13a and 14a. When it vibrates, for example, when it spreads outward, it flexes and spreads toward the piezoelectric elements 13a and 14a. Therefore, the mechanical coupling signals generated in these piezoelectric elements 13a and 14a are in the opposite phases as shown in B and C of FIG. 4, and therefore, when the mechanical coupling signals are combined at point D of FIG. The mechanical coupling signal is small. The mechanical coupling signal is amplified by the charge amplifier 20 and the amplifier 25, rectified by the rectifier 26, smoothed by the smoother 27, and then level-determined by the determiner 28, and the determination result is output from the monitor signal terminal 29. To be done. H, I, in FIG.
The output of each J point is shown in FIG. That is, when the output I of the smoother 27 is between a and b, the output of the monitor signal terminal 29 becomes a low level as indicated by J in FIG. On the other hand, for example, when the detection plate 14 shown in FIG. 3 is damaged or its lead wire is broken, both the angular velocity signal and the mechanical coupling signal become zero level, as shown in C of FIG. As a result, at point D, a mechanical coupling signal is generated only from the piezoelectric element 13a, and the mechanical coupling signal level becomes much higher than before. Therefore, at this time, the output of the smoother 27 becomes larger than the point a as shown by I in FIG. 4, and as a result, the decision unit 28 produces a high level output as shown by J in FIG. When both the detection plates 13 and 14 are damaged or both lead wires are broken, the output of the smoother 27 is smaller than the point b of I in FIG. 4, and the output of the determiner 28 is high at this time as well. It will output the level. When such a high level output is output, it is determined that the angular velocity sensor has failed and information is transmitted to the device used.

FIG. 5 shows another embodiment. In this embodiment, a synchronous detector 30 is provided between an amplifier 25 and a smoother 27.
, The synchronous detection is performed by the feedback signal of the drive signal feedback circuit, that is, the signal from the point A in FIG. That is, since the angular velocity signal is also mixed in the mechanical coupling signal flowing into the amplifier 25, this angular signal is canceled and the mechanical coupling signal level is brought close to an accurate value. Therefore, as described above, the signal of A in FIG. 6 flowing to the point A in FIG. 5 is delayed by 90 degrees in the phase shifter 31, and the output from the amplifier 25 is synchronously detected by the signal having the 90 degree phase delay. If
As shown by I in FIG. 6, the angular velocity signal is canceled and the mechanical coupling signal level can be brought close to an accurate value.

FIG. 7 shows another embodiment. In this embodiment, as an initial setting, the mechanical coupling signals obtained from the piezoelectric elements 13a and 14a are set to 0 when added at point D in FIG. It is a thing. That is, while the addition shown in FIGS. 3 and 5 is in a state other than 0, in this embodiment, the detection plates 13 or 14 are trimmed to generate the piezoelectric elements 13a and 14a. The sum of the mechanical coupling signals is initialized to 0. FIG. 8D shows that, for example, the mechanical coupling signal is not generated until the detection plate 14 is damaged or the lead wire is disconnected. However, after this failure, the mechanical coupling signal is not generated from the piezoelectric element 14a, so that the mechanical coupling signal appears as shown in D of FIG. As a result, as shown in J of FIG. 8, the output of the determiner 28 becomes high level, and this is a signal from the monitor signal terminal 29 via the logical sum circuit 32 to inform that the angular velocity sensor has failed as shown in L of FIG. Will be output. Further, in the present embodiment, the feedback signal of the drive signal, that is, the output of the full-wave rectifier 18 is supplied to the OR circuit 32 via the determiner 33. this is,
In the present embodiment, the purpose is to notify the failure from the monitor signal terminal 29 even when the drive plates 11 and 12 are not driven. Therefore, in the present embodiment, the drive signal is supplied to the logical sum circuit 32 through the judging device 33, and the judging device 33 outputs a high level when the feedback signal is 0, which is a logical value. The failure can be notified by being output from the monitor signal terminal 29 via the summing circuit 32. FIG. 9 shows another embodiment. Also in this embodiment, the detection plate 13 or 14 is trimmed and initialized so that it becomes 0 when the mechanical coupling signals obtained from the piezoelectric elements 13a and 14a are added. The signal from the piezoelectric element 13a is amplified by the charge amplifier 20a, the signal from the piezoelectric element 14a is amplified by the charge amplifier 20b, and the signals obtained by adding them by the adder 34 are output from the output terminal 24 to the angular velocity output. Is taken out as. Further, the subtractor 35 subtracts the output of the charge amplifier 20b from the output of the charge amplifier 20a, and the subsequent processing outputs the monitor signal from the monitor signal terminal 29 as a monitor signal. The waveform of each part is shown in FIG. Although some examples have been shown in the above embodiment, the amplifier 2
5, the rectifier 26 and the smoother 27 may be omitted. Also, I explained using a tuning fork type angular velocity sensor, but it is a triangular prism type,
Since mechanical coupling signals are always generated in the angular velocity sensors of the cylinder type, the sound piece type, and the cylindrical type, it is possible to detect a failure by using the mechanical coupling signal.

[0013]

As described above, according to the angular velocity sensor of the present invention, a pair of tuning fork drive plates and a tip of each of the pair of drive plates are provided.
Vibration consisting of a detection plate installed in an orthogonal relationship
Body and the drive plate for vibrating the vibrating body.
The drive means provided and the drive direction of the vibrating body are orthogonal to each other.
In order to obtain the angular velocity output generated in the direction
A detection means provided, the detection means detects a mechanical coupling signal resulting from mechanical coupling between the detection plate and the drive plate, and the failure determination is performed using the mechanical coupling signal. Since it is configured, it becomes possible to detect whether or not the angular velocity sensor is in a state capable of performing a normal detection operation. Also, it is not necessary to separately provide a means for generating this mechanical coupling signal.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an embodiment of the present invention.

FIG. 2 is an enlarged perspective view of a main part of FIG.

3 is a control circuit diagram of FIG.

FIG. 4 is a waveform diagram of FIG.

FIG. 5 is a control circuit diagram of another embodiment of the present invention.

6 is a waveform diagram of FIG.

FIG. 7 is a control circuit diagram of still another embodiment of the present invention.

8 is a waveform diagram of FIG. 7.

FIG. 9 is a control circuit diagram of still another embodiment of the present invention.

10 is a waveform diagram of FIG.

[Explanation of symbols]

11 Drive plate 11a piezoelectric element 12 Drive plate 12a Piezoelectric element 13 Detection plate 13a Piezoelectric element 14 Detection plate 14a Piezoelectric element 24 output terminals 29 Monitor signal terminal

─────────────────────────────────────────────────── --Continued from the front page (56) Reference JP-A-2-266214 (JP, A) JP-A-6-58760 (JP, A) JP-A-4-215017 (JP, A) JP-A-6- 18267 (JP, A) JP-A-6-207946 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01C 19/56 G01P 9/04

Claims (8)

(57) [Claims] 1. A pair of tuning fork drive plates and a pair of drives
Detection provided at the tip of each plate in an orthogonal relationship
A vibrating body consisting of a plate and a vibrating body
Drive means provided on the drive plate for
To obtain the angular velocity output generated in the direction orthogonal to the driving direction
And a detection means provided on the detection plate for
An angular velocity sensor configured to detect a mechanical coupling signal resulting from mechanical coupling between a knowledge plate and the drive plate by the detection means and to determine a failure using the mechanical coupling signal. 2. A material in which the driving means and the detecting means have piezoelectricity.
The angular velocity sensor according to claim 1, which comprises a charge. 3. A mechanical coupling signal obtained from a pair of detecting means.
Signal is amplified by a charge amplifier, rectified, smoothed, and then supplied to the decision unit.
The angular velocity sensor according to claim 1, wherein the angular velocity sensor is configured to be supplied . 4. A structure in which the sum of mechanical coupling signals obtained from a pair of detection means is initialized to a predetermined value other than 0.
The angular velocity sensor according to Item 3 . 5. The angular velocity sensor according to claim 3 , wherein the sum of the mechanical coupling signals obtained from the pair of detecting means is initialized to 0 . 6. An output and a machine of a judging device connected to a driving means.
The output of the discriminator to which the mechanical coupling signal is input is supplied to the logical sum circuit.
The angular velocity sensor according to claim 5 , wherein the angular velocity sensor is configured to be supplied . 7. A mechanical coupling signal obtained from a pair of detecting means.
Initialize the sum of the numbers to a predetermined value other than 0, and
Of the mechanically coupled signal obtained from these detection means.
Mechanical coupling amplified by this charge amplifier
Feed the signal to the drive signal feedback circuit
The back signal is phase-converted with a 90-degree phase shifter
2. A structure in which the detection is performed and smoothed before being supplied to the judging device.
The angular velocity sensor described in. 8. The sum of the mechanical coupling signals obtained from the pair of detecting means is initialized to 0, and the sum of the mechanical coupling signals is set to 0 .
The mechanical coupling signal obtained from each
Amplify with and subtract the output of these other charge amplifiers
The signal is rectified, smoothed, and then supplied to the judgment device.
The angular velocity sensor according to claim 1 .