JP2005114436A - Vibration gyro drive and detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the angular velocity while reducing the noise. <P>SOLUTION: The vibration gyro 1 containing piezoelectric elements 3a, 3b formed on the oscillator 2 is driven by a self excitation oscillation circuit including the impedance conversion circuit 4 connected with the piezoelectric elements 3a, 3b, the angular velocity applied on the vibration gyro 1 is detected by the output of the vibration gyro 1 by the detection system circuit including the differential amplifier circuit 7 connected with the piezoelectric elements 3a, 3b. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  Conventionally, as such a vibrating gyroscope, those in which a piezoelectric element is attached to a triangular prism-shaped vibrator and those in which electrodes are printed on a cylindrical vibrator have been put into practical use.

  FIG. 7 is a block diagram showing a configuration of a conventional vibration gyro drive detection device 100 using the vibration gyro 1 in which the piezoelectric element 103a, the piezoelectric element 103b, and the piezoelectric element 103c are formed on the side surface of the triangular prism-shaped vibrator 102. is there.

  The vibration gyro drive detection device 100 includes an impedance conversion circuit 104 connected to the piezoelectric elements 103a and 103b of the vibration gyro 101, an addition circuit 105 and a differential amplification circuit 107 connected to the impedance conversion circuit 104, and the above An oscillation circuit 106 connected to the adder circuit 105, a synchronous detection circuit 108 connected to the oscillation circuit 106 and the differential amplifier circuit 107, and a DC amplifier circuit 109 connected to the synchronous detection circuit 108 are provided. An oscillation circuit 106 is connected to the piezoelectric element 103 c of the vibration gyro 101.

  In the vibration gyro drive detection device 100, the vibration gyro 101 oscillates by a self-excited oscillation circuit formed by the vibration gyro 101, the impedance conversion circuit 104, the addition circuit 105, and the oscillation circuit 106, and the piezoelectric element 103c used as a drive piece. Flexurally vibrates in a direction perpendicular to the formation surface. In this state, when the vibratory gyro 101 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 103 a and the piezoelectric element 103 b used as the detection piece, and a detection output is obtained from the differential amplifier circuit 107. At this time, the signal for driving the vibrating gyroscope 101 is a signal having the same phase and the same magnitude in the piezoelectric element 103a and the piezoelectric element 103b. Therefore, the signal for driving the vibration gyro 101 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. The synchronous detection circuit 108 synchronously detects a signal corresponding to the magnitude of the rotational angular velocity output from the differential amplifier circuit 107 with the output of the oscillation circuit 106, that is, a signal for driving the vibration gyro 101.

  The rotational angular velocity applied to the vibration gyro 1 can be measured by qs that the synchronous detection output from the synchronous detection circuit 108 is amplified by the DC amplification circuit 109 and measured.

  Here, the impedance conversion circuit 104 has an input having a high impedance Z2 and an output having a low impedance Z3, and separates the impedance Z1 between the piezoelectric elements 103a and 103b and the impedance Z4 between the inputs of the adder circuit 105. It is used to If the impedance conversion circuit 104 is not provided, the impedance Z1 between the piezoelectric elements 103a and 103b and the impedance Z4 between the inputs of the adding circuit 105 are not separated, and an output difference generated between the piezoelectric elements 103a and 103b. Becomes a size obtained by multiplying by Z4 / (Z1 + Z4), and becomes smaller than the case where the impedance conversion circuit 104 is provided.

  8 shows a configuration of a conventional vibration gyro drive detection device 110 using a vibration gyro 111 in which six electrodes 113a, 113b, 113c, 113d, 113e, and 113f are formed on the side surface of a columnar vibrator 112. FIG.

  In this vibration gyro drive detection device 110, the electrodes 113a, 113b, 113c of the vibration gyro 111 are independent of each other, and the electrodes 113d, 113e, 113f are connected to a common ground. The impedance conversion circuit 114 is connected to the electrodes 113a and 113b of the vibration gyro 111, the addition circuit 115 and the differential amplification circuit 117 are connected to the impedance conversion circuit 114, and the oscillation circuit 116 is connected to the addition circuit 115. A synchronous detection circuit 118 is connected to the oscillation circuit 116 and the differential amplification circuit 117, a DC amplification circuit 119 is connected to the synchronous detection circuit 118, and the oscillation circuit 116 is connected to the electrode 113 c of the vibration gyro 111. Yes.

  In the vibration gyro drive detection device 110, the vibration gyro 111 oscillates by the self-excited oscillation circuit formed by the vibration gyro 111, the impedance conversion circuit 114, the adder circuit 115, and the oscillation circuit 116, and the electrode 113c used as a drive piece. Flexurally vibrates in a direction perpendicular to the side surface. In this state, when the vibratory gyro 111 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 113a and the electrode 113b used as the detection piece, and a detection output is obtained from the differential amplifier circuit 117. At this time, the signals for driving the vibrating gyroscope 111 have the same phase and the same magnitude in the electrodes 113a and 113b. Therefore, the signal for driving the vibration gyro 111 is canceled by the differential amplifier circuit 117. That is, only a signal corresponding to the magnitude of the rotational angular velocity is output from the differential amplifier circuit 117. The synchronous detection circuit 118 synchronously detects a signal corresponding to the magnitude of the rotational angular velocity output from the differential amplifier circuit 117 with the output of the oscillation circuit 116, that is, a signal for driving the vibration gyro 111.

  The rotational angular velocity applied to the vibration gyro 111 can be measured by amplifying and measuring the synchronous detection output by the synchronous detection circuit 118 by the DC amplification circuit 119.

  Here, the impedance conversion circuit 114 has an input having a high impedance Z12 and an output having a low impedance Z13, so that the impedance Z11 between the electrodes 113a and 113b and the impedance Z14 between the inputs of the adder circuit 115 are separated. It is used for. If the impedance conversion circuit 114 is not provided, the impedance Z11 between the electrodes 113a and 113b and the impedance Z14 between the inputs of the addition circuit 115 are not separated, and the output difference generated between the electrodes 113a and 113b is Z14 / ( Z11 + Z14), which is smaller than when the impedance conversion circuit 114 is provided (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 9-15456

  By the way, in the vibration gyro drive detection device that detects the output of the vibration gyro known as described above, the power supply noise causes a potential difference between the outputs of the impedance conversion circuit 14, and the output noise of the differential amplifier circuit is reduced. It was one of the increasing factors.

  Therefore, the present invention has been proposed in view of such a conventional situation, and an object of the present invention is to provide a vibration gyro drive detection device that can detect angular velocity with reduced noise.

  The present invention is a vibration gyro drive detection device that drives a vibration gyro including a detection piece formed on a vibrating body and detects the output thereof, an impedance conversion circuit connected to the detection piece, and this impedance conversion An addition circuit connected to the circuit; an oscillation circuit connected to the addition circuit; a self-excited oscillation circuit constituted by the vibration gyro; and a detection system circuit including a differential amplifier circuit connected to the detection piece; The vibration gyro is driven by a self-excited oscillation circuit including an impedance conversion circuit connected to the detection piece, and the vibration gyro is connected to the vibration gyro by a detection system circuit including a differential amplifier circuit connected to the detection piece. A vibration gyro drive detecting device characterized in that an applied angular velocity is detected from the output of the vibration gyro.

  In the present invention, the vibration gyro including the detection piece formed on the vibrating body is driven by the self-excited oscillation circuit including the impedance conversion circuit connected to the detection piece, and the difference connected to the detection piece is detected. By detecting the angular velocity applied to the vibration gyro from the output of the vibration gyro by a detection system circuit including a dynamic amplification circuit, it is possible to provide a vibration gyro drive detection device designed to reduce noise.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  Note that the present invention is not limited to the following examples, and it goes without saying that modifications can be made without departing from the scope of the present invention.

  FIG. 1 is a block diagram showing a configuration of a vibration gyro drive detection device 10 using a vibration gyro 1 in which a piezoelectric element 3a, a piezoelectric element 3b, and a piezoelectric element 3c are formed on a side surface of a triangular prism-shaped vibrator 2. As shown in FIG.

  Here, as shown in the perspective view of FIG. 2A and the cross-sectional view of FIG. 2B, the vibrating gyroscope 1 is generally mechanical such as Elinba, iron-nickel, quartz, glass, crystal, ceramic, and the like. A triangular prism-shaped vibrator 2 made of a material that generates vibrations is provided, and a piezoelectric element 3a, a piezoelectric element 3b, and a piezoelectric element 3c are formed on a side surface of the vibrator 2.

  The vibration gyro drive detection device 10 includes an impedance conversion circuit 4 and a differential amplifier circuit 7 connected to the piezoelectric element 3a and the piezoelectric element 3b of the vibration gyro 1, and an addition circuit 5 connected to the impedance conversion circuit 4. An oscillation circuit 6 connected to the adder circuit 5; a synchronous detection circuit 8 connected to the oscillation circuit 6 and the differential amplifier circuit 7; and a DC amplifier circuit 9 connected to the synchronous detection circuit 8. The oscillation circuit 6 is connected to the piezoelectric element 3 c of the vibration gyro 1.

  FIG. 3 shows a time chart of voltage waveforms in each part of the vibration gyro drive detection device 10. In FIG. 3, the case where there is no rotation around the major axis of the vibrating gyroscope 1 is shown as stationary, and the case where the rotation around the major axis is added is shown as when the rotational angular velocity is added.

  In this vibration gyro drive detection device 10, the vibration gyro 1 oscillates by a self-excited oscillation circuit formed by the vibration gyro 1, the impedance conversion circuit 4, the addition circuit 5, and the oscillation circuit 6, and the piezoelectric element 3 c used as a drive piece. Flexurally vibrates in a direction perpendicular to the forming surface.

  That is, the vibration gyro 1 is driven by the oscillation output Vgo of the oscillation circuit 6 applied to the piezoelectric element 3c. Then, the output Vgl of the piezoelectric element 3a and the output Vgr of the piezoelectric element 3b of the vibration gyro 1 are input to the adder circuit 5 as Vzl and Vzr via the impedance conversion circuit 4, and the addition circuit 5 adds the Vzl and Vzr. The output Vsa is fed back to the oscillation circuit 6.

  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 Vgl−Vgr is generated between the piezoelectric element 3 a and the piezoelectric element 3 b used as the detection piece, and an output Vda is obtained from the differential amplifier circuit 7. At this time, the signal for driving the vibrating gyroscope 1 is the output of the piezoelectric element 3a and the piezoelectric element 3b at rest, and 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 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.

  The output Vda of the differential amplifier circuit 7 is converted into a DC signal Vsd by synchronous detection by the synchronous detection circuit 8. The synchronous detection circuit 8 converts the output Vda of the differential amplifier circuit 7 into a signal Vdr by full-wave rectification at the timing of the clock signal Vck, and 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.

  Here, the impedance conversion circuit 4 has an input having a high impedance Z2 and an output having a low impedance Z3, and separates the impedance Z1 between the piezoelectric elements 3a and 3b and the impedance Z4 between the inputs of the adder circuit 5 from each other. It is used to If the impedance conversion circuit 4 is not provided, the impedance Z1 between the piezoelectric element 3a and the piezoelectric element 3b and the impedance Z4 between the inputs of the adder circuit 5 are not separated, and an output difference generated between the piezoelectric element 3a and the piezoelectric element 3b. Becomes a size obtained by multiplying by Z4 / (Z1 + Z4), and becomes smaller than the case where there is an impedance conversion circuit.

  Since the impedance conversion circuit 4 only converts the impedance at the input and output and does not affect the magnitude of the signal, the output Vgl of the piezoelectric element 3a and one output Vzl of the impedance conversion circuit 4 have the same magnitude. Thus, the output Vgr of the piezoelectric element 3b and the other output Vzr of the impedance conversion circuit 4 have the same magnitude. Therefore, at the output Vsa of the adder circuit 5, the signal corresponding to the Coriolis force is canceled out and becomes the sum of the outputs of the piezoelectric element 3a and the piezoelectric element 3b at rest. An oscillation circuit is formed by a positive feedback loop including the adder circuit 5, the vibration gyro 1, the impedance conversion circuit 4, and the oscillation circuit 6, and self-oscillates at the resonance frequency of the vibration gyro 1.

  When the output voltage of a switching regulator made with an oscillation frequency of several hundred kilohertz or more is supplied to the power source of the vibration gyro drive detection device 10 as described above, power source noise jumps between the two outputs of the impedance conversion circuit 4. Signal noise. Here, when there is a difference in the way in which power supply noise jumps into the two outputs of the impedance conversion circuit 4, a potential difference due to noise occurs between the two outputs Vzl and Vzr. The two outputs Vzl and Vzr of the impedance conversion circuit 4 including the signal noise are added by the addition circuit 5 and input to the vibration gyro 1 through the oscillation circuit 6.

  Of course, the signal noise is also present on the output Vgo of the oscillation circuit 6, but the vibration gyro 1 functions in the same manner as the band pass filter, and therefore components other than the resonance frequency of the vibration gyro 1 are removed. Therefore, since the signal noise is removed from the outputs of the piezoelectric elements 3a and 3b, the output Vda of the differential amplifier circuit 7 does not include the signal noise and is not affected by power supply noise. The detection device 10 can be provided.

  Here, an example of a characteristic diagram showing the output of the vibration gyroscope 1 is shown in FIG. FIG. 4 shows the output Vgl of the piezoelectric element 3a or the output Vgr of the piezoelectric element 3b. The vertical axis represents the signal magnitude, and the horizontal axis represents the frequency f. The output of the vibration gyro 1 is modulated with a frequency fo, and this frequency fo is normally set to about 10 k to 100 kHz. From this characteristic diagram, it can be seen that the vibrating gyroscope functions in the same manner as a band-pass filter.

  FIG. 5 is a block diagram showing a configuration of a vibration gyro drive detection device 20 using the vibration gyro 11 in which six electrodes 13a, 13b, 13c, 13d, 13e, and 13f are formed on the side surface of the columnar vibrator 12. It is.

  Here, as shown in the perspective view of FIG. 6A and the cross-sectional view of FIG. 6B, the vibration gyro 11 generally generates mechanical vibrations such as crystal and ceramic and has piezoelectric characteristics. A columnar vibrator 12 made of a material is provided, and six electrodes 13a, 13b, 13c, 13d, 13e, and 13f are formed on the side surface of the vibrator 12.

  In this vibration gyro drive detection device 20, the electrodes 13a, 13b, 13c of the vibration gyro 11 are independent from each other, and the electrodes 13d, 13e, 13f are connected to a common ground. The impedance conversion circuit 14 and the differential amplifier circuit 17 are connected to the electrodes 13 a and 13 b of the vibration gyro 11, and the addition circuit 15 is connected to the impedance conversion circuit 14. The oscillation circuit 16 is connected to the addition circuit 15. A synchronous detection circuit 18 is connected to the oscillation circuit 16 and the differential amplifier circuit 17, a DC amplification circuit 19 is connected to the synchronous detection circuit 18, and the oscillation circuit 16 is connected to the electrode 13 c of the vibration gyro 11. Has been.

  As described above, the output signals of the electrodes 13a and 13b, which are detection pieces, are input to the impedance conversion circuit 14, the output of the impedance conversion circuit 14 is input to the addition circuit 15, and the electrodes 13a and 13b, which are detection pieces, are also input. By inputting the output signal to the differential amplifier circuit 17, it is possible to provide a vibration gyro drive detection device that is not affected by power supply noise.

  The circuits 14, 15, 16, 17, 18, 19 in the vibration gyro drive detection device 20 have the same function as the circuits 4, 5, 6, 7, 8, 9 in the vibration gyro drive detection device 10 described above. The details thereof will not be described.

It is a block diagram which shows the structure of the vibration gyro drive detection apparatus using the vibration gyro provided with a triangular prism-shaped vibrator. It is a figure which shows the structure of a vibration gyro provided with the said triangular prism-shaped vibrator | oscillator. It is a time chart of the voltage waveform in each part of the above-mentioned vibration gyro drive detection device. It is a characteristic view showing the output of the said vibration gyro. It is a block diagram which shows the structure of the vibration gyro drive detection apparatus using the vibration gyro provided with a column-shaped vibrator. It is a figure which shows the structure of a vibration gyro provided with the said cylindrical vibrator. It is a block diagram which shows the structure of the conventional vibration gyro drive detection apparatus using the vibration gyro provided with a triangular prism-shaped vibrator. It is a block diagram which shows the structure of the conventional vibration gyro drive detection apparatus using the vibration gyro provided with a circular prism-shaped vibrator.

Explanation of symbols

 1,11 vibrating gyroscope, 2,12 vibrator, 3a, 3b, 3c piezoelectric element, 4,14 impedance conversion circuit, 5,15 addition circuit, 6,16 oscillation circuit, 7,17 differential amplification circuit, 8,18 Synchronous detection circuit, 9, 19 DC amplification circuit, 10, 20 Vibration gyro drive detection device, 13a, 13b, 13c, 13d, 13e, 13f electrode

Claims (1)

A vibration gyro drive detection device for driving a vibration gyro including a detection piece and a drive piece formed on a vibrating body and detecting an output thereof,
An impedance conversion circuit connected to the detection piece; an addition circuit connected to the impedance conversion circuit; an oscillation circuit connected to the addition circuit; and a self-excited oscillation circuit configured by the vibration gyro;
A detection system circuit including a differential amplifier circuit connected to the detection piece,
The vibration gyro is driven by a self-excited oscillation circuit including an impedance conversion circuit connected to the detection piece, and applied to the vibration gyro by a detection system circuit including a differential amplifier circuit connected to the detection piece. A vibration gyro drive detection device characterized by detecting an angular velocity from the output of the vibration gyro.

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