JPH0656300B2 - Vibration type angular velocity detector - Google Patents

Description

The present invention relates to a vibration type angular velocity detecting device.

[Prior art]

Conventionally, as a vibration type angular velocity detecting device of this type, as disclosed in Japanese Patent Application Laid-Open No. 59-188561, a first device that extends from a movable body and vibrates in the vibration direction of the movable body is disclosed.
A vibrating piece, a second vibrating piece extending from the first vibrating piece and vibrating in a direction perpendicular to the first vibrating piece when an angular velocity is generated in the movable body, and the first vibrating piece in the vibrating direction. A first piezoelectric element that is fixed so as to be distorted to vibrate the first vibrating piece by performing a piezoelectric conversion action, and a second piezoelectric element that is fixed so as to be distorted in the direction of vibration in the vibrating direction and that performs a piezoelectric conversion action and is necessary for defining the angular velocity. Second piezoelectric element that generates a different detection signal,
There is a structure in which the detection signal is synchronously detected based on the result of the piezoelectric conversion action of the first piezoelectric element, and the synchronous detection result is generated as a synchronous detection signal generated as an output signal representing the angular velocity.

[Problems to be solved by the invention]

However, in such a configuration, since the piezoelectric conversion characteristics of the above-described piezoelectric elements fluctuate sensitively with changes in ambient temperature, the sensitivity to angular velocity fluctuates according to changes in ambient temperature, or the angular velocity is zero. In spite of this, there is a problem that the value of the output signal, that is, the offset amount changes. Further, if the first vibrating reed described above is simply vibrated at a frequency near its resonance point, it is difficult for the phase difference between both inputs to the synchronous detection means to be 90 degrees, and the offset amount is added to the output signal. There is also a problem that a large error is mixed in.

Therefore, in the present invention, in order to deal with these problems, the third piezoelectric element is newly fixed to the first vibrating piece, and the result of the piezoelectric conversion action of the third piezoelectric element becomes constant. It is an object of the present invention to provide a vibration type angular velocity detection device which drives the first piezoelectric element and maintains the phase difference between both inputs to the synchronous detection means at 90 degrees.

[Means for solving problems]

In solving such problems, the structural features of the present invention are as follows.
A vibrating member having a first piezoelectric element and a second piezoelectric element is provided, and when the vibrating member is vibrated by the first piezoelectric element, a vibration component orthogonal to the vibrating direction is output to the output signal from the second piezoelectric element. A vibration-type angular velocity detection device configured to detect the angular velocity applied to the vibrating member based on the first piezoelectric element, the vibrating angular velocity detecting device having the same characteristics as the second piezoelectric element. A third piezoelectric element that outputs an alternating-current signal corresponding to the vibration of the vibrating member in the vibration direction, a phase-shift control unit that shifts the alternating-current signal output from the third piezoelectric element by 90 degrees, and the third piezoelectric element The amplitude of the AC signal that is phase-shifted by 90 degrees is adjusted by the phase control means so that the amplitude of the AC signal output from the first piezoelectric element is the drive signal. Drive means for applying the voltage, and synchronous detection means for synchronously detecting the output signal of the second piezoelectric element based on the alternating signal shifted by 90 degrees by the phase control means to generate an angular velocity signal. I am trying.

[Action effect]

In the above structure, when the vibrating member is vibrated by the first piezoelectric element, if an angular velocity is applied to the vibrating member in a direction orthogonal to the vibrating direction, the output signal from the second piezoelectric element is synchronously detected by the synchronous detecting means. , The angular velocity applied to the vibrating member is detected.

Further, in the above configuration, a third piezoelectric element having the same characteristics as the second piezoelectric element is provided in the vibrating member, and an AC signal corresponding to the vibration in the vibrating direction of the vibrating member by the first piezoelectric element is output, and the phase control is performed. The AC signal is phase shifted by 90 degrees by means. Furthermore, the drive means adjusts the amplitude of the AC signal that is phase-shifted by 90 degrees, applies the adjusted AC signal as a drive signal to the first piezoelectric element, and the amplitude of the AC signal output from the third piezoelectric element. To be constant.

Therefore, since the third piezoelectric element and the second piezoelectric element have the same characteristics, the constant amplitude of the AC signal from the third piezoelectric element means that the output signal output from the second piezoelectric element is constant. Is controlled to be constant, and as a result, even if the ambient temperature changes, the fluctuation of the offset amount contained in the output signal of the second piezoelectric element is suppressed. Furthermore, the control of the output signals of the second piezoelectric element and the third piezoelectric element in the above relationship means that the phase relationship of the output signals of the second piezoelectric element and the third piezoelectric element is kept constant. That is, as a result, the phase relationship between the two inputs for the synchronous detection in the synchronous detection means can be kept constant, and the error in the synchronous detection can be reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 2 and FIG. 2 show a vibration type angular velocity detecting device according to the present invention applied to detection of angular velocity of a roll angle of a vehicle,
This angular velocity detecting device is composed of a vibrating mechanism M mounted on a vehicle body of a vehicle and an electric circuit E connected to the vibrating mechanism M. The vibrating mechanism M includes a rectangular parallelepiped metal base 1
0, the vibrator 20, and the piezoelectric elements 30a, 30b, 40
a, 40b, 50a, 50b, and a metal base 1
0 extends rearward from a part of the vehicle body with both upper and lower surfaces 11 and 12 thereof being horizontal.

The vibrating body 20 includes a vibrating plate 21 formed in a U shape from a strip-shaped metal plate and a pair of vibrating pieces 2 formed of a strip-shaped metal plate.
2 and 23, the diaphragm 21 is
The base portion 21a is vertically soldered to the support portion 13a extending horizontally rearward from the rear surface 13 of the metal substrate 10, and both vibrating portions 21a and 21b facing each other are extended horizontally rearward of the vehicle body. Then, the metal base 10 is assembled. In such a case, the vibrating portion 21b is located directly above the vibrating portion 21c, and both upper and lower surfaces of each vibrating portion 21b, 21c are horizontal. The vibrating bar 22 extends in a longitudinal shape from the center of the tip of the vibrating part 21b in the same manner as the vibrating part 21b with its plate width direction orthogonal to the plate width direction of the vibrating part 21b. The direction is orthogonal to the plate width direction of the vibrating portion 21c, and the vibrating portion 21c is moved from the center of the tip of the vibrating portion 21c.
Like c, it extends longitudinally. In addition, each vibrating unit 21
b and 21c vibrate in the X direction (see FIG. 1), and the vibrating pieces 22 and 23 vibrate in the Y direction (see FIG. 1) under Coriolis force according to the angular velocity ω of the vehicle. The left side surfaces of both vibrating bars 22 and 23 are both in the same vertical plane.

The piezoelectric element 30a is attached to the lower surface of the vibrating portion 21b of the vibrating plate 21 by its one side electrode to vibrate the vibrating portion 21b under its piezoelectric conversion action, while the piezoelectric element 30b
Is attached to the upper surface of the vibrating portion 21c of the vibrating plate 21 by its one side electrode so as to vibrate the vibrating portion 21c based on its piezoelectric conversion action. , 30b is grounded at one side electrode (second
See figure). The piezoelectric element 40a is attached to the left side surface of the vibrating piece 22 by its one side electrode, while the piezoelectric element 40b is
The one side electrode is attached to the left side surface of the vibrating piece 23, and the piezoelectric elements 40a and 40b are connected to each other at the other side electrodes to form a common terminal.
A detection voltage necessary for defining the angular velocity ω is generated from the common terminal based on the piezoelectric conversion action according to the vibration of 3 in the Y direction. Note that one electrode of each piezoelectric element 40a, 40b is grounded. The various characteristics of the piezoelectric elements 40a and 40b are the same, including the characteristics with respect to the ambient temperature.

The piezoelectric element 50a is attached to the upper surface of the vibrating portion 21b of the vibrating plate 21 by one electrode thereof, while the piezoelectric element 50b is attached.
Is attached to the lower surface of the vibrating portion 21c of the vibrating plate 21 at its one side electrode, and both piezoelectric elements 50a and 50b are connected to each other at their other side electrodes to form a common terminal. , Each of the vibrating portions 21b, 21c based on the piezoelectric conversion action corresponding to the vibration of the both vibrating portions 21b, 21c in the X direction.
The vibration of c is detected and generated as a detection voltage from the common terminal. In this case, the piezoelectric elements 50a and 50b have the same characteristics as those of the piezoelectric elements 40a and 40b. One electrode of each of the piezoelectric elements 50a and 50b is grounded.

The electric circuit E is, as shown in FIG.
amplifier 60 connected to a and 40b, and both piezoelectric elements 50
The amplifier 70 is connected to a and 50b, and these amplifiers 60 and 70 have the same characteristics as each other.
It is fixed to the upper and lower surfaces 11 and 12 of 0 (see FIG. 1). As a result, unnecessary electrical coupling between the amplifiers 60 and 70 and other elements can be reduced, and the piezoelectric elements 40a, 40b, 50a and 50b can be connected to the metal substrate 10 via the amplifiers 60 and 70, respectively. Can be thermally coupled. Further, the amplifier 60 receives the detection voltage from the common terminal of both piezoelectric elements 40a and 40b and amplifies it to generate an amplified detection voltage, while the amplifier 70 receives the detection voltage from the common terminal of both piezoelectric elements 50a and 50b and amplifies it. Then, an amplified detection voltage is generated.

In response to the amplified detection voltage from the amplifier 70, the phase shift circuit 80 shifts the phase of this amplified detection voltage by about 90 degrees to generate a phase shift voltage. The rectifier circuit 90 responds to the amplified detection voltage from the amplifier 70 and rectifies the amplified detection voltage to generate a rectified voltage. The reference voltage generating circuit 100 uses both piezoelectric conversion elements 30a and 30a to keep the amplified detection voltage from the amplifier 70 constant.
Generate a reference voltage to control the input voltage to b.
The differential amplifier 110 amplifies the difference between the rectified voltage from the rectifying circuit 90 and the reference voltage from the reference voltage generating circuit 100 to generate a differential amplified voltage. The multiplying circuit 120 multiplies the phase shift voltage from the phase shift circuit 80 by the differential amplification voltage from the differential amplifier 110, and uses the multiplication result as a feedback voltage corresponding to the input voltage on the other side electrodes of the piezoelectric elements 30a and 30b. Apply to.

The synchronous detection circuit 130 responds to the phase shift voltage from the phase shift circuit 80 and synchronously detects the amplified detection voltage from the amplifier 60 in association with the phase shift voltage and generates the synchronous detection result as a synchronous detection voltage. The filter 140 removes frequency components other than the low frequency component of the synchronous detection voltage from the synchronous detection circuit 130, and generates the low frequency component as a filter voltage. The amplifier circuit 150 amplifies the filter voltage from the filter 140, and generates the amplification result as an angular velocity voltage representing the angular velocity ω.

In the present embodiment configured as described above, if the vehicle is run at the angular velocity ω = 0 under the operation of the device of the present invention, each vibrating portion 21 of the vibrating plate 21 of the vibrating mechanism M is driven.
a and 21b are piezoelectric elements 30 based on the base 21a.
The piezoelectric elements 50a and 50b generate a detection voltage from their common terminals in response to the vibrations of the vibrating portions 21b and 21c by vibrating in the X direction in cooperation with a and 30b, and the amplifier 70 applies the detected voltage. Amplified as an amplified detection voltage, the phase shift circuit 80 phase shifts the amplified detection voltage by 90 degrees in response to the amplified detection voltage from the amplifier 70 to generate a phase shift voltage. The amplified detection voltage is rectified to generate a rectified voltage.

Then, the differential amplifier 110 amplifies the difference between the rectified voltage from the rectifier circuit 90 and the reference voltage from the reference voltage generation circuit 100 as a differential amplification voltage, and the multiplication circuit 120.
The phase shift voltage from 0 is multiplied by the differential amplification voltage from the differential amplifier 100 to generate a feedback voltage, which is applied to each piezoelectric element 30a, 30b. This means that each piezoelectric conversion action of both piezoelectric elements 30a and 30b, that is, the vibration of each oscillating portion 21b and 21c is feedback-controlled by the feedback voltage from the multiplication circuit 120 so that the amplification detection voltage from the amplifier 70 is made constant. Means that.

Further, since the angular velocity ω = 0 at this stage, the Y-direction vibration component of each of the vibrating pieces 22 and 23 of the vibrating mechanism M is zero, but the piezoelectric elements 40a and 40b are piezoelectrically converted by various disturbances. An offset amount based on the disturbance is generated as a detection voltage from its common terminal, and the amplifier 60 amplifies the detection voltage from both piezoelectric elements 40a and 40b as an amplified detection voltage. Then, the synchronous detection circuit 130 synchronously detects the amplification detection voltage from the amplifier 60 based on the phase shift voltage from the phase shift circuit 80 to generate a synchronous detection voltage, and in response thereto, the filter 140 generates a filter voltage. In addition, the amplifier circuit 150 generates an angular velocity voltage in response to the filter voltage. In such a case, the phase of the phase shift voltage from the phase shift circuit 80 is 90 times greater than the phase of the amplified detection voltage from the amplifier 70.
Since they are deviated by a degree, the synchronous detection in the synchronous detection circuit 130 is made to reduce the influence of the amplified detection voltage (that is, the offset amount) from the amplifier 60 on the synchronous detection output. As a result, The angular velocity voltage from the amplifier circuit 150 has a value corresponding to approximately ω = 0 without being mixed as an error of the drift amount.

In such a state, if the ambient temperature changes, the vibration-voltage conversion ratio of each piezoelectric element 40a, 40b, 50a, 50b changes. Therefore, as described above, each amplifier 6
0 and 70 have the same temperature characteristics, and the piezoelectric elements 40a, 40b, 50a and 50b have the same temperature characteristics, and are thermally coupled by the metal substrate 10 via the amplifiers 60 and 70. Therefore, the temperature characteristics of the amplifiers 60, 70 change in the same state as the ambient temperature changes, and the temperature characteristics of the piezoelectric elements 40a, 40b, 50a, 50b become the same as the ambient temperature changes. It changes with the state. This means that each piezoelectric element 40a, 40b, 50
It means that the vibration-voltage conversion ratios of a and 50b change with the values which match each other according to the change of the ambient temperature.

Further, if the vibration speed of each of the vibrating portions 21b and 21c of the diaphragm 21 is Vs, the detection voltage from both piezoelectric elements 50a and 50b is E1, and the detection voltage from both piezoelectric elements 40a and 40b is E2, Generally, E1∝V ... (1) E2∝ω × V ... (2) holds. Therefore, each piezoelectric element 40a, 40b, 50
Assuming that the vibration-voltage conversion ratios of a and 50b both fluctuate K times due to changes in ambient temperature, the amplified detection voltage E1 from the amplifier 70 is fed back to the piezoelectric elements 30a and 30b of the multiplication circuit 120 as described above. Since it is controlled and is always constant, the amplification detection voltage E2 does not change even when the vibration speed V becomes (1 / K) because the vibration-voltage conversion ratio changes to K times. This means that both the amplified detection voltage from the amplifier 60 and the phase shift voltage from the phase shift circuit 80, which are both inputs to the synchronous detection circuit 130, are always kept unchanged regardless of changes in the ambient temperature. To do. Therefore, the output of the synchronous detection circuit 130, that is, the angular velocity voltage from the amplifier circuit 150 is maintained at a value corresponding to approximately ω = 0, regardless of the characteristic change of each piezoelectric element with respect to the change in ambient temperature. In addition, the above effects
In the case of ω ≠ 0, substantially the same can be achieved.

Next, a modification of the first embodiment will be described with reference to FIG. 3. In this modification, instead of the phase shift circuit 80 described in the above embodiment, a phase comparison circuit 80A and a filter 80B are used.
A characteristic of the configuration is that the PLL circuit including the voltage-controlled oscillation circuit 80C is adopted. Phase comparison circuit 80
A compares the phase of the feedback voltage generated from the multiplication circuit 120 as described later with the phase of the amplified detection voltage from the amplifier 70, and generates the difference between these two phases as a phase difference voltage. The filter 80B filters the phase difference voltage from the phase comparison circuit 80A to generate a filter voltage. Voltage controlled oscillator circuit 8
0C corresponds to the filter voltage from the filter 80B,
The phase difference between the amplified detection voltage from the amplifier 70 and the phase is 90.
Generates an alternating voltage with a frequency. The multiplication circuit 120 converts the AC voltage from the voltage controlled oscillator circuit 80C into the differential amplifier 1
The differential amplified voltage from 10 is multiplied and the multiplication result is generated as a feedback voltage. The synchronous detection circuit 130 synchronously detects the amplified detection voltage from the amplifier 60 based on the phase voltage from the voltage controlled oscillation circuit 80C and generates a synchronous detection voltage. The rest of the configuration is similar to that of the above embodiment.

Therefore, in this modified example configured as described above, when the vehicle is run at the angular velocity ω = 0, the amplifiers 60 and 70 generate amplified detection voltages, respectively, as in the case of the above embodiment. The differential amplifier 110 generates a differential amplified voltage. Then, the phase comparison circuit 80A causes the multiplication circuit 12
When the phase difference voltage is generated by comparing the phases of the feedback voltage from 0 and the amplified detection voltage from the amplifier 70, the filter 80
B generates a filter voltage, and the voltage controlled oscillator 80C has a phase difference of 90 from the phase of the amplified detection voltage from the amplifier 70.
The multiplying circuit 120 multiplies the AC voltage by a differential amplification voltage from the differential amplifier 110, generates a feedback voltage, and applies it to the piezoelectric elements 30a and 30b. This means that each piezoelectric conversion action of both piezoelectric elements 30a and 30b, that is, the vibration of each oscillating portion 21b and 21c is feedback-controlled by the feedback voltage from the multiplication circuit 120 so that the amplification detection voltage from the amplifier 70 is made constant. Means that.

Further, as described above, when the amplifier 60 generates an amplification detection voltage (corresponding to the offset amount) and the voltage controlled oscillation circuit 80C generates an AC voltage, the synchronous detection circuit 130 causes the AC detection voltage to be based on the amplification detection voltage. Is synchronously detected to generate a synchronous detection voltage, and the amplifier circuit 150 cooperates with the filter 140 to generate an angular velocity voltage. In such a case, the AC voltage from the voltage controlled oscillation circuit 80C in cooperation with the phase comparison circuit 80A and the filter 80B is deviated from the amplified detection voltage from the amplifier 70 by 90 degrees in phase, so that the synchronous detection circuit 130. The coherent detection in FIG. 6 reduces the influence of the amplified detection voltage (that is, the offset amount) from the amplifier 60 on the coherent detection output, and as a result, the angular velocity voltage from the amplifier circuit 150 is the offset amount. Is a value corresponding to approximately ω = 0 without being mixed as an error of. The other operational effects are substantially the same as in the above embodiment.

In addition, in the embodiment and the modified example, both vibrating portions 21b and 21c of the vibrating mechanism M are integrally formed by the vibrating plate 21, but instead of this, two vibrating portions corresponding to the vibrating portions 21b and 21c are vibrated. Alternatively, the vibrating pieces may be independently adopted and each of these vibrating pieces may be fixed to the metal substrate 10.

Further, in the embodiment and the modified example, both the vibrating portions 21b and 21c and the both vibrating pieces 22 and 23 are provided in the vibrating mechanism M, but the present invention is not limited to this, and the vibrating portion 21c and the vibrating piece 23 may be omitted. Alternatively, in this case, a vibrating piece corresponding to the vibrating portion 21b may be adopted and fixed to the metal base 10.

Further, in the above-mentioned embodiments and modified examples, an example in which the present invention is applied to a vehicle has been described, but the present invention is not limited to this, and the present invention is applied to detect angular velocities of various movable bodies such as ships, aircraft, and the like. Good.

In addition, as for the correspondence relationship between each constituent element described in the claims and the embodiment, the vibrating body 20 corresponds to a vibrating member, and the piezoelectric elements 30a and 30b, the piezoelectric elements 40a and 40b, and the piezoelectric elements 50a and 50b are They correspond to the first, second and third piezoelectric elements, respectively. The phase shift circuit 80 corresponds to the phase control means, and the rectifier circuit 90, the reference voltage generation circuit 100, the operational amplifier 110, and the multiplication circuit 120 correspond to the drive means. Further, the synchronous detection circuit 130 corresponds to the synchronous detection means.

[Brief description of drawings]

1 and 2 are overall configuration diagrams showing an embodiment of the present invention, and FIG. 3 is an electric circuit diagram showing a modified example of the embodiment. Explanation of reference numerals 20 ... Vibrating body, 21b, 21c ... Vibrating section, 22, 2
3 ... Resonator, 30a, 30b, 40a, 40b, 50
a, 50b ... Piezoelectric element, 80 ... Phase shift circuit, 80A ...
... Phase comparison circuit, 80C ... Voltage controlled oscillator circuit, 90 ...
… Rectifier circuit, 100 …… Reference voltage generation circuit, 110 ……
Differential amplifier, 120 ... Multiplier circuit, 130 ... Synchronous detection circuit.

Claims (1)

[Claims] 1. A vibrating member having a first piezoelectric element and a second piezoelectric element, wherein when the vibrating member is vibrated by the first piezoelectric element, a vibrating component orthogonal to a vibrating direction thereof is generated by the second piezoelectric element. A vibration-type angular velocity detecting device configured to detect an angular velocity applied to the vibrating member by detecting based on an output signal from the vibrating member, the vibrating member having the same characteristics as the second piezoelectric element, A third piezoelectric element that outputs an alternating-current signal corresponding to the vibration of the vibrating member in the vibration direction of the first piezoelectric element, and a phase control unit that shifts the alternating-current signal output from the third piezoelectric element by 90 degrees. The phase control means adjusts the amplitude of the AC signal that is phase-shifted by 90 degrees so that the amplitude of the AC signal output from the third piezoelectric element is constant, and the adjusted AC signal is used as a drive signal. (1) a driving means for applying to the piezoelectric element, and a synchronous detecting means for synchronously detecting the output signal of the second piezoelectric element based on the AC signal phase-shifted by 90 degrees by the phase control means to generate an angular velocity signal Vibration type angular velocity detector.