JP2005055255A - Gyroscope output detection method and gyroscope output detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gyroscope output detection method and a gyroscope output detection device which reduce a drift or a noise. <P>SOLUTION: This gyroscope output detection method is a method for detecting an output from a oscilating gyroscope 1 including detection pieces 3a, 3b where a oscilator 2 is formed. In the method, output signals from the detection pieces 3a, 3b are differentially amplified, and a signal at least on the lower band side than a frequency band wherein a signal corresponding to an angular velocity signal including a resonance frequency appears remarkably is removed from the differentially-amplified output signal, and the output signal after removing the signal on the lower band side is synchronously detected, and the angular velocity signal from which a noise generated in the output from the oscilating gyroscope 1 is removed is detected. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to detection of a gyroscope used for detecting camera shake of a video camera, direction detection of a car navigation system, attitude control of a moving body such as an automobile, and the like, and in particular, output of a columnar vibration gyro using bending vibration. TECHNICAL FIELD The present invention relates to a gyro output detection method for measuring a gyro and a gyro output detection device using the method.

  In recent years, a vibration gyro has been widely used for detecting a camera shake of a video camera, a traveling position of a car navigation, or for controlling a posture of a moving body. Conventionally, as such a vibrating gyroscope, a piezoelectric element pasted on a quadrangular prism-shaped vibrator, a piezoelectric element pasted on a triangular prism-shaped vibrator, an electrode printed on a cylindrical vibrator, etc. Is in practical use. FIG. 12 shows an example of a vibration gyro using a conventional quadrangular columnar vibrator. 12A is a perspective view, and FIG. 12B is a cross-sectional view. The vibrating gyroscope 1 is attached to the first side surface of the quadrangular columnar vibrator 2 so that the piezoelectric elements 3a and 3b are arranged. FIG. 13 shows a conventional circuit block for detecting the output of the vibration gyro 1, that is, a vibration gyro detection circuit 111. A second side surface facing the first side surface of the vibrating gyroscope 1 is connected to the reference potential Vref. The output of the oscillation circuit 106 is connected to the piezoelectric element 3a and the piezoelectric element 3b through the resistor 104a and the resistor 104b, respectively. Outputs from the respective piezoelectric elements 3 a and 3 b are input to the adder circuit 105, and an output of the adder circuit 105 is input to the oscillation circuit 106. The outputs of the piezoelectric element 3 a and the piezoelectric element 3 b are input to the differential amplifier circuit 107, synchronously detected by the synchronous detector circuit 108, and the signal is amplified by the DC amplifier circuit 109. A timing signal is supplied from the oscillation circuit 106 to the synchronous detection circuit 108.

  The vibration gyro 1 oscillates by a self-excited oscillation circuit formed by the vibration gyro 1, the resistor 104 a, the resistor 104 b, the adder circuit 105, and the oscillation circuit 106, and bends and vibrates in a direction perpendicular to the first side surface and the second side surface. To do. In this state, when the vibratory gyroscope 1 is rotated around the long axis, the direction of the bending vibration is changed by the Coriolis force. As a result, an output difference is generated between the piezoelectric element 3 a and the piezoelectric element 3 b, and an output is obtained from the differential amplifier circuit 107. At this time, the signal for driving the vibrating gyroscope 1 is a signal having the same phase and the same magnitude in the piezoelectric element 3a and the piezoelectric element 3b. For this reason, the signal for driving the vibration gyro 1 is canceled by the differential amplifier circuit 107. That is, only a signal corresponding to the magnitude of the rotational angular velocity is output from the differential amplifier circuit 107. Therefore, the rotational angular velocity applied to the vibrating gyroscope 1 can be measured by measuring the direct current amplified output after synchronous detection of this output. The piezoelectric element 3a and the piezoelectric element 3b are used as a shared drive piece and detection piece.

FIG. 14 shows another example of a vibration gyro using a conventional triangular prism-shaped vibrator. 1A is a perspective view, and FIG. 1B is a cross-sectional view. The vibration gyro 21 is formed by forming a piezoelectric element 23a, a piezoelectric element 23b, and a piezoelectric element 23c on a side surface of a triangular prism-shaped vibrator 22.
FIG. 15 shows a conventional circuit block for detecting the output of the vibration gyro 21, that is, a vibration gyro detection circuit 131. In the vibration gyro detection circuit 131, the oscillation circuit 126 is connected to the piezoelectric element 23a and the piezoelectric element 23b through the resistor 124a and the resistor 124b, and is also connected to the piezoelectric element 23c. Further, the outputs of the piezoelectric element 23 a and the piezoelectric element 23 b are input to the differential amplifier circuit 127. The output of the differential amplifier circuit 127 is synchronously detected by the synchronous detector circuit 128, and the signal is amplified by the DC amplifier circuit 129. A timing signal is supplied from the oscillation circuit 126 to the synchronous detection circuit 128.
In the vibration gyro detection circuit 131, the vibration gyro 21 oscillates by a self-excited oscillation circuit formed by the vibration gyro 21 and the resistor 124 a, the resistor 124 b and the oscillation circuit 126, and is used as a driving piece. Flexurally vibrates in a direction perpendicular to the forming surface. In this state, when the vibration gyro 21 is rotated around the long axis, the direction of the bending vibration is changed by the Coriolis force. As a result, an output difference is generated between the piezoelectric element 23 a and the piezoelectric element 23 b used as the detection piece, and an output is obtained from the differential amplifier circuit 127. At this time, the signal for driving the vibrating gyroscope 21 is a signal having the same phase and the same magnitude in the piezoelectric element 23a and the piezoelectric element 23b. For this reason, the signal for driving the vibration gyro 21 is canceled by the differential amplifier circuit 127. That is, only a signal corresponding to the magnitude of the rotational angular velocity is output from the differential amplifier circuit 127. Therefore, the rotational angular velocity applied to the vibration gyro 21 can be measured by synchronously detecting this output and measuring the direct current amplified output.

FIG. 16 shows still another example of a vibration gyro using a conventional columnar vibrator. 1A is a perspective view, and FIG. 1B is a cross-sectional view. In the vibration gyro 41, six electrodes 43a, 43b, 43c, 43d, 43e, and 43f are sequentially formed on the side surface of the columnar vibrator 22.
FIG. 17 shows a conventional circuit block for detecting the output of the vibration gyro 41, that is, a vibration gyro detection circuit 151. The electrodes 43a, 43b, and 43c are independent of each other, and the electrodes 43d, 43e, and 43f are connected to a common ground. The output of the oscillation circuit 146 is connected to the electrode 43c. Further, the outputs of the electrodes 43 a and 43 b are input to the adder circuit 145. The output of the adder circuit 145 is input to the oscillation circuit 146. The outputs of the electrodes 43a and 43b are input to the differential amplifier circuit 147. The output of the differential amplifier circuit 147 is synchronously detected by the synchronous detector circuit 148, and the signal is amplified by the DC amplifier circuit 149. A timing signal is supplied from the oscillation circuit 146 to the synchronous detection circuit 148.
In the vibration gyro detection circuit 151, the vibration gyro 41 oscillates by a self-excited oscillation circuit formed by the vibration gyro 41, the addition circuit 145, and the oscillation circuit 146, in a direction orthogonal to the side surface of the electrode 43 c used as a drive piece. Bends and vibrates. In this state, when the vibration gyro 41 is rotated around the long axis, the direction of the bending vibration is changed by the Coriolis force. As a result, an output difference is generated between the electrode 43a and the electrode 43b used as the detection piece, and an output is obtained from the differential amplifier circuit 147. At this time, signals for driving the vibrating gyroscope 41 have the same phase and the same magnitude in the electrodes 43a and 43b. For this reason, the signal for driving the vibration gyro 41 is canceled by the differential amplifier circuit 147. That is, only a signal corresponding to the magnitude of the rotational angular velocity is output from the differential amplifier circuit 147. Therefore, the rotational angular velocity applied to the vibration gyro 41 can be measured by synchronously detecting this output and measuring the direct current amplified output.

FIG. 18 shows another example of a vibrating gyroscope having one detection piece in a conventional vibrating body. 1A is a perspective view, and FIG. 1B is a cross-sectional view. The vibration gyro 61 is formed by forming a piezoelectric element 63a and a piezoelectric element 63b on side surfaces orthogonal to each other of a quadrangular columnar vibrator 62.
FIG. 19 shows a conventional circuit block for detecting the output of the vibration gyro 61, that is, a vibration gyro detection circuit 171. In the vibration gyro detection circuit 171, the vibrator 62 is connected to a common ground. The output of the oscillation circuit 166 is connected to the piezoelectric element 63a. Further, the output from the piezoelectric element 63 b is input to the AC amplifier circuit 167, and the output from the AC amplifier circuit 167 is input to the oscillation circuit 166. The output from the AC amplifier circuit 167 is synchronously detected by the synchronous detector circuit 168, and the signal is amplified by the DC amplifier circuit 169. A timing signal is supplied from the oscillation circuit 166 to the synchronous detection circuit 168.
In the vibration gyro detection circuit 171, the vibration gyro 61 oscillates by a self-excited oscillation circuit formed by the vibration gyro 61, the AC amplification circuit 167, and the oscillation circuit 166, and is orthogonal to the side surface of the piezoelectric element 63a used as a drive piece. Bends and vibrates in the direction of In this state, when the vibration gyro 61 is rotated around the long axis, the direction of the bending vibration is changed by the Coriolis force. As a result, the output of the piezoelectric element 63b used as the detection piece changes. This amount of change is a signal corresponding to the magnitude of the rotational angular velocity. Therefore, the rotational angular velocity applied to the vibration gyro 61 can be measured by AC amplification of this signal, synchronous detection, and measurement of the DC amplified output.

In addition, as described in Patent Documents 1 to 5, various types of vibration gyro detection methods have been proposed.
Japanese Patent No. 2801013 Japanese Patent Laid-Open No. 11-118492 Japanese Patent Laid-Open No. 11-257969 Japanese Patent Laid-Open No. 11-83495 Japanese Patent Laid-Open No. 11-83396

  In the above-described conventional method for detecting the output of a vibration gyro, the phase difference or potential difference between the outputs of the two detection pieces due to a change in ambient temperature or the vibration of the vibrator, even when the detector is stationary. Caused drift and noise. In addition, drift and noise generated in a differential amplifier circuit, a synchronous detection circuit, and the like cannot be ignored because they are DC amplified.

FIG. 20 is an example of a characteristic diagram in which an output of a vibration gyro used for camera shake detection of a video camera is detected. The vertical axis represents the magnitude of the angular velocity signal S and the noise N, and the horizontal axis represents the magnitude of the frequency f. The frequency required for camera shake detection of a video camera is about 10 to 100 Hz, but there are noise components in the same frequency band, and it has been difficult to improve the S / N by removing the noise.
FIG. 21 is an example of a characteristic diagram in which the output of a vibration gyro used for detecting the direction of the car navigation system is detected. The vertical axis represents the magnitude of the angular velocity signal S and the noise N, and the horizontal axis represents the magnitude of the frequency f. The frequency required for the direction detection of the car navigation system is about 0 to 10 Hz, but there is also a noise component in the same frequency band, and it is similarly difficult to improve the S / N by removing the noise. It was.

  In view of the above, the present invention provides a gyro output detection method and a gyro output detection device that reduce drift and noise.

A gyro output detection method according to the present invention is a method for detecting an output of a vibration gyro including a detection piece on which a vibrating body is formed. The output signal of the detection piece is differentially amplified, and the differentially amplified output signal is detected. From the frequency band at least lower than the frequency band in which the signal corresponding to the angular velocity signal including the resonant frequency appears prominently, synchronously detect the output signal after removing this low-frequency signal,
An angular velocity signal from which noise generated in the output of the vibration gyro is removed is detected.

  A gyro output detection device according to the present invention is a method for detecting an output of a vibration gyro including a detection piece on which a vibrating body is formed, a differential amplifier circuit for inputting an output signal of the detection piece, and the differential amplification A removal circuit that removes at least a signal in a lower frequency range than a frequency band in which a signal corresponding to an angular velocity signal including a resonance frequency appears prominently from an output signal of the circuit, and a synchronous detection circuit that synchronously detects the output signal of the removal circuit And detecting an angular velocity signal from which noise generated in the output of the vibration gyro is removed.

  According to the gyro output detection method of the present invention, the output signal from the vibration gyro detection piece is in a state where the signal S and the noise component N in the necessary frequency band are separated. From the output signal after differential amplification, a filter circuit or the like removes a signal (a signal including a noise component N) at least on the lower frequency side than the frequency band in which the signal S corresponding to the angular velocity signal including the resonance frequency appears prominently. Thus, the angular velocity signal from which the noise component generated in the output of the vibration gyro is removed is detected by the subsequent synchronous detection.

  According to the gyro output detection device of the present invention, an output signal in which the signal S and the noise component N in the necessary frequency band are separated is output from the differential amplifier circuit that receives the output signal of the detection piece of the vibration gyro. Is done. By providing a removal circuit such as a filter circuit between the differential amplifier circuit and the synchronous detection circuit, a signal at least on a lower frequency side than a frequency band in which a signal corresponding to an angular velocity signal including a resonance frequency appears prominently by the removal circuit. (A signal including a noise component) can be removed. Therefore, by detecting the output signal from the removal circuit synchronously with the synchronous detection circuit, the angular velocity signal from which the noise component generated in the output of the vibration gyro is removed is detected.

According to the gyro output detection method of the present invention, it is possible to detect an angular velocity signal from which noise and drift generated in the output of the vibration gyro are removed. Therefore, it is suitable for application to, for example, camera shake detection of a video camera, direction detection in a car navigation system, or posture control of a moving body such as an automobile.
By using the high-pass filter, it is possible to remove a signal (a signal including a noise component) on a lower frequency side than a frequency band in which a signal corresponding to the angular velocity signal including the resonance frequency appears prominently.
By using the band pass filter, it is possible to remove signals on the low frequency side and high frequency side (signals including noise components) from the frequency band in which a signal corresponding to the angular velocity signal including the resonance frequency appears prominently.
By using the band elimination filter, it is possible to remove signals on the low frequency side and high frequency side (signals including noise components) from the frequency band in which a signal corresponding to the angular velocity signal including the resonance frequency appears prominently. .
When two detection pieces are formed on the vibrator and the output signals from the two detection pieces are input to the differential amplification, the angular velocity signal from which the noise component has been removed can be detected practically and reliably.

The gyro output detection device according to the present invention detects an angular velocity signal from which noise and drift generated in the output of the vibration gyro are removed by a simple configuration in which a removal circuit is provided between the differential amplifier circuit and the synchronous detection circuit. can do. Therefore, it is suitable for application to, for example, camera shake detection of a video camera, direction detection in a car navigation system, or posture control of a moving body such as an automobile.
By using a high-pass filter circuit for the removal circuit, it is possible to remove a signal (a signal including a noise component) on the lower frequency side than a frequency band in which a signal corresponding to an angular velocity signal including a resonance frequency appears prominently.
By using a band-pass filter circuit for the removal circuit, signals on the lower and higher frequencies (signals containing noise components) than the frequency band in which signals corresponding to angular velocity signals including the resonance frequency appear prominently are removed. be able to.
By using a band elimination filter circuit in the removal circuit, signals on the low and high frequencies (signals containing noise components) are removed from the frequency band in which signals corresponding to angular velocity signals including the resonance frequency appear prominently. can do.
When two detection pieces are formed on the vibrating body and the output signals from the two detection pieces are input to differential amplification, a gyro output detection device that can detect angular velocity signals from which noise components have been removed practically and reliably is constructed. can do.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an embodiment of a gyro output detection method and a gyro output detection device according to the present invention. The gyro output detection device 11 according to the present embodiment uses the vibration gyro 1 having the same configuration as that shown in FIG. In other words, the vibrating gyroscope 1 is configured such that the piezoelectric elements 3a and 3b are arranged side by side on the first side surface of the quadrangular columnar vibrator 2. The material of the vibrator 2 is generally formed of a material that causes mechanical vibration, such as Elinba, iron-nickel, quartz, glass, quartz, and ceramic. In the vibrator 2, the second side surface facing the first side surface on which the piezoelectric elements 3 a and 3 b are formed is connected to the reference potential Vref. The piezoelectric elements 3 a and 3 b of the vibration gyro 1 are each connected to an adding circuit 5, and the adding circuit 5 is connected to an oscillation circuit 6. The output side of the oscillation circuit 6 is connected to the piezoelectric elements 3a and 3b via the resistors 4a and 4b, respectively. On the other hand, the piezoelectric elements 3a and 3b are respectively connected to a differential amplifier circuit 7, and a filter circuit 10, a synchronous detection circuit 8 and a DC amplifier circuit 9 which are sequentially removed circuits are sequentially connected to the output side of the differential amplifier circuit 7, An output terminal t1 is derived from the DC amplifier circuit 9. The synchronous detection circuit 8 is connected to the oscillation circuit 6 so that a timing signal is supplied from the oscillation circuit 6. The filter circuit 10 serving as a removal circuit, which will be described later, is a signal at least on the lower side of the frequency band in which a signal corresponding to the angular velocity signal including the resonance frequency appears prominently from the output signal of the differential amplifier circuit 7. A circuit to be removed.

  In this gyro output detection device 11, the output Vgo of the oscillation circuit 6 is input to the piezoelectric elements 3a and 3b through the resistors 4a and 4b, and the outputs Vgr and Vgl of the piezoelectric elements 3a and 3b are input to the adder circuit 5, The output VSa of the addition circuit 5 is input to the oscillation circuit 6. On the other hand, the output Vgr of the piezoelectric element 3 a and the output Vgl of the piezoelectric element 3 b are input to the differential amplifier circuit 7, and the output Vda of the differential amplifier circuit 7 is input to the filter circuit 10. The output Vfo of the filter circuit 10 is synchronously detected by the synchronous detection circuit 8, and the timing is performed using the clock signal Vck generated by the oscillation circuit 6. The synchronous detection output Vsd is amplified by the DC amplifier circuit 9 and output from the output terminal t1.

  Next, a method for detecting the gyro output by the gyro output detection device 11 of the present embodiment will be described in detail. FIG. 2 shows a time chart of voltage waveforms in each part of the gyro output detection device 11 of FIG. FIG. 2 shows the case where the vibration gyro 1 (see FIG. 12) does not rotate around the long axis as stationary, and the case where rotation around the vibration long axis is applied as the rotational angular velocity is applied. Represents.

In the gyro output detection device 11, the vibration gyro 1 oscillates by the self-excited oscillation circuit formed by the vibration gyro 1, the resistors 4 a and 4 b, the adder circuit 5, and the oscillation circuit 6. Bends and vibrates in a direction perpendicular to.
When the vibrating gyroscope 1 is in a bending vibration state, when the vibrating gyroscope 1 is rotated around the major axis, the direction of the bending vibration is changed by the Coriolis force. By changing the direction of the bending vibration, an output difference Vgl−Vgr (see FIGS. 2B2 and C2) is generated between the piezoelectric element 3a and the piezoelectric element 3b, so that the output Vda (see FIG. 2E2) from the differential amplifier circuit 7. Is obtained. At this time, the signals for driving the vibrating gyroscope 1 are the outputs Vgl and Vgr of the piezoelectric element 3a and the piezoelectric element 3b at rest, and are signals having the same phase and the same magnitude in the piezoelectric element 3a and the piezoelectric element 3b. For this reason, the signals Vgl and Vgr for driving the vibration gyro 1 are canceled by the differential amplifier circuit 7. Next, signals corresponding to the Coriolis force are signals Vcl and Vcr having the same magnitude in opposite phases in the piezoelectric element 3a and the piezoelectric element 3b. Therefore, the output Vda of the differential amplifier circuit 7 is a signal proportional to Vcl−Vcr. That is, when a rotational angular velocity is applied to the vibration gyro 1, the piezoelectric element 3a outputs a signal Vgl (solid line) including a stationary signal Vgl (dashed line) for driving the vibration gyro and a signal Vcl (one-dot chain line) corresponding to the Coriolis force. And a signal Vgr (solid line) including a stationary signal Vgr (dashed line) for driving the vibrating gyroscope and a signal Vcr (dashed line) corresponding to the Coriolis force are output from the piezoelectric element 3b (FIG. 2B2, FIG. 2). 2C2). Accordingly, both signals Vgl (broken line) and Vgr (broken line) are canceled by the differential amplifier circuit 7 and a signal Vda (see FIG. 2E2) proportional to the signal Vcl−Vcr is output from the differential amplifier circuit 7.

  By removing only the low-frequency noise component included in the output Vda of the differential amplifier circuit 7 by the filter circuit 10, a signal Vfo (see FIG. 2F2) having a significantly improved S / N is obtained. Next, the output Vfo of the filter circuit 10 is converted into a DC signal VSd (see FIG. 2H2) by synchronous detection. The synchronous detection circuit 8 converts the output Vfo of the filter circuit 10 into a signal Vfr by full-wave rectification at the timing of the clock signal Vck, and then integrates it to obtain a DC signal Vsd. Only the angular velocity signal generated by the rotation can be detected by DC-amplifying the signal Vsd to a predetermined magnitude by the DC amplifier circuit 9.

  The output Vsa of the adder circuit 5 is the sum of the outputs Vgl and Vgr from the piezoelectric element 3a and the piezoelectric element 3b at rest because the signals Vcl and Vcr corresponding to the Coriolis force are canceled. An oscillation circuit is formed by a positive feedback loop including the adding circuit 5, the vibration gyro 1, the resistor 4 a, the resistor 4 b, and the oscillation circuit 6, and self-oscillates at the resonance frequency of the vibration gyro 1. Each piezoelectric element 3a, 3b uses a drive piece and a detection piece in common.

Next, the relationship between the angular velocity signal generated by the rotation and the low frequency noise will be described in more detail.
In the case of the conventional example without the filter circuit 10 described above, as described above, drift and noise caused by changes in ambient temperature, vibration of the vibrator, and the like, and drift caused by a differential amplifier circuit and a synchronous detection circuit, etc. And noise cannot be ignored. Then, as shown by the output of the vibration gyro used for the camera shake detection of the video camera of FIG. 20 or the output of the vibration gyro used for the direction detection in the car navigation system of FIG. There are an angular velocity signal S and a noise component N having a large level, and it is difficult to improve the S / N ratio.

  On the other hand, paying attention to the output of the differential amplifier circuit 7 described above, since the signals Vcl and Vcr corresponding to the Coriolis force are modulated at the self-excited oscillation frequency, the output Vda of the differential amplifier circuit 7 is similarly modulated. Has been. By utilizing this, it is possible to remove only noise in the frequency band necessary for detecting the angular velocity signal S.

  FIG. 3 is an example of a characteristic diagram at the output Vda of the differential amplifier circuit 7 described above. The vertical axis represents the magnitude of the signal S and noise N corresponding to the Coriolis force, and the horizontal axis represents the magnitude of the frequency f. The signal S is modulated with a frequency fo, and this frequency fo is a self-excited oscillation frequency and is usually set to about 10 k to 100 kHz. In addition, since the frequency band of camera shake detection is about 10 to 100 Hz and the frequency band of direction detection is about 0 to 10 Hz, it can be said that the signal S and the noise component of the necessary frequency band are separated.

  FIG. 4 is an example of a characteristic diagram showing the filter circuit output Vfo when a high-pass filter is used in the filter circuit 10 of FIG. The vertical axis represents the magnitude of the signal S and noise N corresponding to the Coriolis force, and the horizontal axis represents the magnitude of the frequency f. For example, it is a characteristic when the cut-off frequency fc of the filter circuit 10 is selected as 1 kHz, and only the noise component in the frequency band necessary for camera shake detection and direction detection is reduced without reducing the signal S corresponding to the Coriolis force. be able to.

Similarly, by using a band-pass filter in the filter circuit 10 of FIG. 1, only the noise component in the frequency band necessary for camera shake detection and direction detection is reduced without reducing the signal S corresponding to the Coriolis force. be able to.
By demodulating the output Vfo of the filter circuit 10 into the DC signal VSd by the synchronous detection circuit 8, the required frequency band drift and noise can be reduced.

  FIG. 5 is an example of a characteristic diagram showing an output characteristic of a vibration gyro in which noise is reduced by the filter circuit 10 of the gyro output detection device according to the present invention, and is particularly used for camera shake detection of a video camera. The vertical axis represents the magnitude of the angular velocity signal S and the noise N, and the horizontal axis represents the magnitude of the frequency f. The frequency required for the hand shake detection is about 10 to 100 Hz, but the noise component in the same frequency band is reduced, so that the S / N is greatly improved.

  FIG. 6 is an example of a characteristic diagram showing an output characteristic of a vibration gyro in which noise is reduced by the filter circuit of the gyro output detection device according to the present invention, and is used particularly for direction detection in a car navigation system. The vertical axis represents the magnitude of the angular velocity signal S and the noise N, and the horizontal axis represents the magnitude of the frequency f. The frequency necessary for direction detection is about 0 to 10 Hz, but the noise component in the same frequency band is reduced, so that the S / N is greatly improved.

  FIG. 7 is an example of a characteristic diagram showing the filter circuit output Vfo when a band-pass filter is used for the filter circuit 10 of the gyro output detection device according to the present invention. The vertical axis represents the magnitude of the signal S and the noise N corresponding to the Coriolis force, and the horizontal axis represents the magnitude of the frequency f. For example, it is a characteristic when the cut-off frequency fc of the filter is selected to be the same frequency as the self-excited oscillation frequency fo, and the signal S corresponding to the Coriolis force is not reduced, but the noise in the frequency band necessary for camera shake detection and direction detection Only the components can be reduced.

  FIG. 8 is an example of a characteristic diagram showing the filter circuit output Vfo when a band elimination filter is used for the filter circuit 10 of the gyro output detection device according to the present invention. The vertical axis represents the magnitude of the signal S and noise N corresponding to the Coriolis force, and the horizontal axis represents the magnitude of the frequency f. For example, it is a characteristic when the cut-off frequency fc of the filter is selected to be 30 Hz, and only the noise component in the frequency band necessary for camera shake detection and direction detection can be reduced without reducing the signal S corresponding to the Coriolis force. it can.

  Furthermore, by increasing the gain of the differential amplifier circuit 7 and setting the gain of the DC amplifier circuit 9 small, drift and noise generated in the differential amplifier circuit 7 are reduced by the filter circuit 10. The generated drift and noise are not greatly amplified by the DC amplifying circuit 9 and can be kept low.

FIG. 9 shows another embodiment of the gyro output detection method and the gyro output detection device according to the present invention. The gyro output detection device 21 according to the present embodiment has the same configuration as that shown in FIG. 15 described above, that is, the piezoelectric elements 23 [23a, 23b, 23c] are formed on each side surface of the triangular prism-shaped vibrator 22, A vibration gyro 21 using two piezoelectric elements 23a and 23b as detection pieces, an oscillation circuit 26, resistors 24a and 24b, a differential amplifier circuit 27, a synchronous detection circuit 28, and a DC amplifier circuit 29 are further provided. A filter circuit 30 similar to the filter circuit 10 in the present invention is connected between the differential amplifier circuit 27 and the synchronous detection circuit 28. The mutual connection relationship of each vibration gyro 21, except for the filter circuit 30, resistors 24a and 24b, oscillation circuit 26, differential amplifier circuit 27, synchronous detection circuit 28, and DC amplifier circuit 29 is the same as in FIG. Because of this, duplicate explanation is omitted.
According to the gyro output detection method and the gyro output detection device 31 according to the present embodiment, by adding the filter circuit 30 between the differential amplifier circuit 27 and the synchronous detection circuit 28, the same as in the above-described embodiment. In addition, drift and noise can be reduced without impairing the angular velocity signal.

FIG. 10 shows another embodiment of the gyro output detection method and the gyro output detection device according to the present invention. The gyro output detection device 51 according to the present embodiment has the same configuration as that shown in FIG. 16 described above, that is, electrodes 43 [43a, 43b, 43c, 43d, 43e, 43f] on each side surface of the columnar vibrator 42. And the piezoelectric element 43a, 43b of which is a detection piece, a vibration gyro 41, an addition circuit 45, an oscillation circuit 46, a differential amplification circuit 47, a synchronous detection circuit 48, and a DC amplification circuit 49, And a filter circuit 50 similar to the filter circuit 10 in the present invention described above is connected between the differential amplifier circuit 47 and the synchronous detection circuit 48. The mutual connection relationship of each vibration gyro 41 except the filter circuit 50, the addition circuit 49, the oscillation circuit 46, the differential amplifier circuit 47, the synchronous detection circuit 48, and the DC amplifier circuit 49 is the same as that of FIG. Therefore, duplicate explanation is omitted.
According to the gyro output detection method and the gyro output detection apparatus 51 according to the present embodiment, by adding the filter circuit 50 between the differential amplifier circuit 47 and the synchronous detection circuit 48, the same as in the above-described embodiment. In addition, drift and noise can be reduced without impairing the angular velocity signal.

FIG. 11 shows another embodiment of the gyro output detection method and the gyro output detection device according to the present invention. The gyro output detection device according to the present embodiment has the same configuration as that shown in FIG. 19 described above, that is, the piezoelectric element 63a and the piezoelectric element 63b are formed on the side surfaces of the quadrangular prism-shaped vibrator 62 that are orthogonal to each other. A vibration gyro 61 using the element 63b as a detection piece, an oscillation circuit 66, an AC amplification circuit 67, a synchronous detection circuit 68, and a DC amplification circuit 69 are provided. Further, the AC amplification circuit 67 and the synchronous detection circuit 68 are A filter circuit 70 similar to the filter circuit 10 in the present invention described above is connected in between. The mutual connection relationships of the vibration gyro 61, the oscillation circuit 66, the AC amplifier circuit 67, the synchronous detection circuit 68, and the DC amplifier circuit 69 other than the filter circuit 70 are the same as those in FIG. To do.
According to the gyro output detection method and the gyro output detection device 71 according to the present embodiment, by adding the filter circuit 70 between the AC amplifier circuit 67 and the synchronous detection circuit 68, the same as in the above-described embodiment. Drift and noise can be reduced without impairing the angular velocity signal.

  According to the gyro output detection method according to the above-described embodiment, the output signals Vgl and Vgr of the two detection pieces (piezoelectric element, electrode) of the vibration gyro are input to the differential amplifier circuit, and the output signal Vda is input to the filter circuit. By removing the signal, the signal on the lower frequency side than the frequency band where the signal S corresponding to the angular velocity signal including the resonance frequency appears prominently, or the signal on the lower and higher frequency sides of this frequency band, particularly the noise signal N, is removed. can do. This low-frequency signal or the signal S from which the low-frequency and high-frequency noise signals N have been removed is synchronously detected by a synchronous detection circuit so that the noise and drift generated in the output of the vibration gyro are removed. Can be detected. This gyro output detection method is suitable for application to camera shake detection of a video camera, direction detection in a car navigation system, or posture control of a moving body such as an automobile.

  According to the gyro output detection device according to the above-described embodiment, the differential amplification circuit that differentially amplifies the output signals Vgl and Vgr of the two detection pieces (piezoelectric element, electrode) of the vibration gyro, and the synchronous detection circuit By connecting a filter circuit between them, the output of the filter circuit includes a signal on the lower frequency side than the frequency band in which the signal S corresponding to the angular velocity signal including the resonance frequency appears prominently, or the lower frequency side of this frequency band and A signal S from which a signal on the high frequency side, particularly the noise signal N is removed, is obtained. By synchronously detecting this signal S with a synchronous detection circuit, it is possible to detect an angular velocity signal from which noise and drift generated in the output of the vibration gyro are removed. This gyro output detection device is suitable for application to camera shake detection of a video camera, direction detection in a car navigation system, or attitude control of a moving body such as an automobile.

  The gyro output detection method and the gyro output detection device of the present invention can also be applied to a case where a vibration gyro having a single detection piece is provided as a vibration gyro.

  Needless to say, the present invention is not limited to the above-described embodiments, and modifications can be made without departing from the scope of the present invention.

The circuit block diagram which shows an example of the gyro output detection method to which this invention is applied is shown. The time chart figure of the voltage waveform in each part of the gyro output detection method shown in FIG. 1 is shown. It is an example of the characteristic view in the differential amplifier circuit output of the gyro output detection method shown in FIG. It is an example of the characteristic figure in the filter circuit output when a high pass filter is used for the filter circuit of the gyro output detection method shown in FIG. It is an example of the characteristic view when using the gyro output detection method shown in FIG. 1 for camera shake detection. FIG. 2 is an example of a characteristic diagram when the gyro output detection method shown in FIG. 1 is used for direction detection. It is an example of the characteristic figure in the filter circuit output when a band pass filter is used for the filter circuit of the gyro output detection method shown in FIG. It is an example of the characteristic figure in the filter circuit output when a band elimination filter is used for the filter circuit of the gyro output detection method shown in FIG. It is a circuit block diagram which shows the other example of the gyro output detection method to which this invention is applied. It is a circuit block diagram which shows the other example different from FIG. 1 of the gyro output detection method to which this invention is applied. It is a circuit block diagram which shows the other example different from FIG. 1 of the gyro output detection method to which this invention is applied. A A perspective view showing an example of a vibrating gyroscope is shown. B shows a cross-sectional view of FIG. The circuit block diagram which shows an example of the conventional gyro output detection method is shown. A A perspective view showing another example of a vibrating gyroscope is shown. B shows a cross-sectional view of FIG. 14A. The circuit block diagram which shows the other example of the conventional gyro output detection method is shown. A The perspective view which shows the other example different from FIG. 14 of a vibration gyro is shown. B shows a cross-sectional view of FIG. 16A. The circuit block diagram which shows the other example different from FIG. 13 of the conventional gyro output detection method is shown. A The perspective view which shows the other example different from FIG. 14 of a vibration gyro is shown. B shows a cross-sectional view of FIG. 18A. The circuit block diagram which shows the other example different from FIG. 13 of the conventional gyro output detection method is shown. It is an example of the characteristic diagram which detected the output of the vibration gyro used for camera shake detection. It is an example of the characteristic diagram which detected the output of the vibration gyro used for direction detection.

Explanation of symbols

1, 2, 41, 61 ..Vibrating gyros 2, 22, 42, 62 ..Vibrators 3 a, 3 b, 23 a, 23 b, 23 c, 63 a, 63 b. .. Electrodes 4a, 4b, 24a, 24b, 104a, 104b, 124a, 124b ..Resistance 5, 45, 105, 145 ..Adder circuits 6, 26, 46, 106, 126, 146, 166 ..Oscillator circuit 7 27, 47, 107, 127, 147 ... Differential amplifier circuits 8, 28, 48, 108, 128, 148, 168 ... Synchronous detection circuits 9, 29, 49, 109, 129, 149, 169 ... DC Amplifier circuit 167 .. AC amplifier circuit 10, 30, 50, 70 ..Filter circuit 11, 31, 51, 71, 111, 131, 151, 171 ..Gyro output detection device

Claims (10)

A method for detecting an output of a vibrating gyroscope including a detecting piece on which a vibrating body is formed,
Differentially amplifying the output signal of the detection piece,
From the differentially amplified output signal, a signal at least on a lower frequency side than a frequency band in which a signal corresponding to an angular velocity signal including a resonance frequency appears prominently is removed,
Synchronously detect the output signal after removing the low-frequency side signal,
Detecting an angular velocity signal from which noise generated in the output of the vibrating gyroscope has been removed;
The gyro output detection method characterized by the above-mentioned. The gyro output detection method according to claim 1, wherein a high-pass filter removes a signal at least on a lower frequency side than a frequency band in which a signal corresponding to the angular velocity signal including the resonance frequency appears prominently. 2. The gyro output detection according to claim 1, wherein a band-pass filter removes signals on a low frequency side and a high frequency side from a frequency band in which a signal corresponding to an angular velocity signal including the resonance frequency appears prominently. Method. The gyro output detection method according to claim 1, wherein a band elimination filter removes at least a signal on a lower frequency side than a frequency band in which a signal corresponding to an angular velocity signal including the resonance frequency appears prominently. The gyro output detection method according to claim 1, wherein two detection pieces are formed on the vibrating body, and an output signal from the two detection pieces is differentially amplified. An apparatus for detecting an output of a vibrating gyroscope including a detecting piece on which a vibrating body is formed,
A differential amplifier circuit for inputting an output signal of the detection piece;
A removal circuit that removes at least a low-frequency side signal from a frequency band in which a signal corresponding to an angular velocity signal including a resonance frequency appears prominently from the output signal of the differential amplifier circuit;
A synchronous detection circuit for synchronously detecting the output signal of the removal circuit,
Detecting an angular velocity signal from which noise generated in the output of the vibrating gyroscope has been removed;
A gyro output detection device characterized by the above. The gyro output detection device according to claim 6, wherein the removal circuit is a high-pass filter circuit. The gyro output detection device according to claim 6, wherein the removal circuit is a band-pass filter circuit. The gyro output detection device according to claim 6, wherein the removal circuit is a band elimination filter circuit. The gyro output detection device according to claim 6, wherein two detection pieces are formed on the vibrating body, and output signals from the two detection pieces are input to a differential amplifier circuit.

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