JPH0650760A - Signal processing circuit for vibrating gyro - Google Patents

Abstract

PURPOSE:To obtain the signal processing circuit, of an equilateral-triangular sound-reed type vibrating gyro, wherein a drift voltage is eliminated and the correction of a phase and the fine correction of an amplitude are not required. CONSTITUTION:Piezoelectric elements 22, 23 are used for driving and a driving signal is supplied from an oscillation circuit 25. A piezoelectric element 24 is used for feed-backing, and its output is input to the oscillation circuit 25. The piezoelectric elements 22, 23 are used also for detection, and their outputs are input to a differential complification circuit 28 via AC coupling circuits 80a, 80b, full-wave rectification circuits 27a, 27b and smoothing circuits 81a, 81b. Thereby, a Coriolis' force which is proportional to the angular velocity of rotation of a vibrator 21 can be detected from the output of the differential amplification circuit 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing circuit for a gyro that detects the rotational angular velocity of a moving body, and more particularly to a signal processing circuit for an equilateral triangular vibrating gyro.

[0002]

2. Description of the Related Art A gyro is used in dead-reckoning navigation of a navigation system, for example, when determining a rotational angular velocity of a vehicle body. Dead reckoning of a navigation system measures the movement (azimuth) of the vehicle body to obtain the current position. The gyro includes a "coma gyro" that uses rotational inertia, an "optical fiber gyro" that uses light interference and phase difference, and a "gas rate gyro" that uses gas flow and temperature difference. However, all of them are large devices that require maintenance and start-up time, and are extremely expensive and not suitable for consumer use. Therefore, a vibration gyro has been developed and commercialized for consumer use. "Vibration gyro", "Tone piece type vibration gyro", "Tuning fork type vibration gyro"
There are also "equal triangle sound piece type vibrating gyro" and the like. Among them, "equal triangle sound piece type vibrating gyro" is high in sensitivity and excellent.

FIG. 11 is a block diagram showing a schematic electrical configuration of a signal processing circuit in a conventional equilateral triangular vibrating gyro. The piezoelectric elements 2 and 3 on the left and right sides of the vibrator 1 of the vibrating gyro are used for driving, and the remaining piezoelectric elements 4 on one side are used for feedback and the output thereof is input to the oscillation circuit 5. Further, the piezoelectric elements 2 and 3 also serve as detection. A drive signal is applied from the oscillation circuit 5 to the piezoelectric elements 2 and 3 via the phase correction circuit 6 to excite the vibrator 1. In that state, when the vibrator 1 is rotated in the direction of reference numeral 7, the voltage generated by the Coriolis force proportional to the rotation angular velocity is superimposed on the drive signal, and the output voltage 8 of the piezoelectric element 2 is increased.
And the output voltage 9 of the piezoelectric element 3 is generated. At this time, the detected voltages on the left and right due to the Coriolis force have opposite phases, so that a difference occurs in the voltage outputs, like the output voltages 8 and 9. The output voltages 8 and 9 of the piezoelectric element are compared with the amplitude correction circuit 1
When the correction signal is corrected to 0 and differentially amplified by the differential amplifier circuit 11, the drive signals of the piezoelectric elements 2 and 3 are canceled out, so that only the voltage 12 generated by the Coriolis force can be taken out. Voltage 1 generated by this Coriolis force
Half-wave rectification of the signal 2 is performed by the synchronous detection circuit 13 to obtain a voltage output 14. The voltage output 14 can be smoothed by the DC amplification circuit 15 to obtain the voltage output 16 proportional to the rotational angular velocity.

[0004]

In the above-described equilateral triangular vibrating gyroscope shown in FIG. 11, the piezoelectric elements 2 and 3 are used.
When a drive signal is applied to the oscillator 1 and the vibrator 1 is rotated in that state, not only the voltage generated by the Coriolis force but also the drift voltage is superimposed on the drive signal. The drift voltage is a voltage generated as a result of the vibrator 1 and the piezoelectric elements 2 and 3 being distorted by an external environment such as temperature and vibration. In the conventional vibration gyro, this drift voltage cannot be removed and is output as it is as an error factor. Further, due to the size of the vibration gyro processing circuit, the size or mounting accuracy of the piezoelectric element, or the variation in the voltage output coefficient of the element itself, a phase difference and an amplitude difference occur in the output voltage of the piezoelectric elements 2 and 3. Therefore, the phase correction circuit 6 and the amplitude correction circuit 10 shown in FIG. 11 are required for the phase correction and the minute amplitude correction.

An object of the present invention is to eliminate drift voltage,
It is an object of the present invention to provide a signal processing circuit of an equilateral triangular piece vibrating gyro, which does not require phase correction and minute amplitude correction.

[0006]

According to the present invention, among the output voltages from the left and right piezoelectric elements of an equilateral triangular vibrating gyro,
In a signal processing circuit of a vibration gyro that detects the Coriolis force and detects the angular velocity corresponding to the Coriolis force, a pair of full-wave rectifier circuits that full-wave rectify the output voltages from the left and right piezoelectric elements A vibration gyro signal processing circuit, comprising: a differential amplifier circuit that amplifies a difference in output voltage from a rectifier circuit.

Further, according to the present invention, a signal processing circuit for a vibration gyro that detects the output voltage from the left and right piezoelectric elements of the equilateral triangular vibrating gyro by the Coriolis force and detects the angular velocity corresponding to the Coriolis force. In, in the output voltage from the left and right piezoelectric elements, a pair of AC coupling circuits for respectively extracting the AC components, a pair of full-wave rectification circuits for full-wave rectifying the AC output voltage from each AC coupling circuit, and each full-wave A vibrating gyro signal processing circuit comprising: a pair of smoothing circuits for respectively smoothing outputs from the rectifier circuits; and a differential amplifier circuit for amplifying a difference between output voltages from the respective smoothing circuits.

[0008]

According to the present invention, the processing circuit of the equilateral triangular vibrating gyro includes a pair of full-wave rectifier circuits and a differential amplifier circuit. The pair of full-wave rectification circuits perform full-wave rectification on the voltages from the left and right piezoelectric elements, respectively. The differential amplifier circuit amplifies the difference in output voltage from each full-wave rectifier circuit.

According to the invention, the processing circuit of the vibration gyro includes a pair of AC coupling circuits, a pair of full-wave rectification circuits, a pair of smoothing circuits, and a differential amplifier circuit. The AC coupling circuit respectively extracts the AC component of the output voltage from the left and right piezoelectric elements. The pair of full-wave rectifier circuits respectively full-wave rectify the AC output voltage from each AC coupling circuit. The pair of smoothing circuits respectively smooth the output from each full-wave rectifier circuit. The differential amplifier circuit amplifies the difference in output voltage from each smoothing circuit. Therefore, in the processing circuit of the vibration gyro, the drift voltage is removed by canceling the drift voltage of the positive phase and the negative phase, and the phase correction and the minute correction of the amplitude become unnecessary.

[0010]

1 is a block diagram showing a schematic electrical configuration of a signal processing circuit in an equilateral triangular vibrating gyroscope according to an embodiment of the present invention. Piezoelectric elements 22 and 23 on the left and right sides of a vibrator 21 of an equilateral triangular vibrating gyroscope.
Is used for driving, and the output of the remaining piezoelectric element 24 on one side is input to the oscillation circuit 25 for feedback. Further, the piezoelectric elements 22 and 23 on the two right and left sides are also used for detection. A drive signal is applied to the piezoelectric elements 22 and 23 from the oscillation circuit 25 via the phase correction circuit 26 to excite the vibrator 21. When the oscillator 21 is rotated in the direction of reference numeral 31 in that state, the voltage generated by the Coriolis force proportional to the rotational angular velocity is superimposed on the drive signal. In addition to the voltage generated by the Coriolis force, the drift voltage is also superimposed on the drive signal.

The output voltage of the piezoelectric element 22 at this time is shown in FIG.
It shows in (1). The important point here is that the first output voltage
A drift voltage is superimposed on the + side of the drive signal with respect to the wave 40, and − with respect to the drive signal with respect to the second wave 41 of the output voltage.
The drift voltage is superimposed on the side. Therefore, FIG.
As shown in (2), the output voltages 40 and 4 of the piezoelectric element
If 1 is full-wave rectified and converted into the output voltages of reference numerals 42 and 43, and this output voltage is smoothed, the drift voltages of the first wave 40 and the second wave 41 cancel each other, so the drift voltage is removed. can do. From the above, the output voltages of the piezoelectric elements 22 and 23 are full-wave rectified by the full-wave rectifier circuits 27a and 27b as shown in FIG. Next, the outputs of the full-wave rectifier circuits 27a and 27b are input to the differential amplifier circuit 28. Differential amplifier circuit 28 in this case
The output voltages of the piezoelectric elements 22 and 23 in FIG. 3 are shown in FIGS. 3 (1) and 3 (2), respectively. There is a voltage difference between the output R signal 45 of the right piezoelectric element 23 and the output L signal 46 of the left piezoelectric element 22. This is because the Coriolis forces work in opposite phases in the right piezoelectric element 23 and the left piezoelectric element 22. Further, the difference in drift voltage between the piezoelectric elements 22 and 23 is also superimposed on the voltage difference. Therefore, by performing differential amplification by the differential amplifier circuit 28, the output 47 in which the voltage generated by the Coriolis force and the drift voltage are superimposed can be taken out. Reference numeral 48 indicates output signals of the piezoelectric elements 22 and 23 in a state where the vibrator 21 is not rotating. Next, the output of the differential amplifier circuit 28 is smoothed by the DC amplifier circuit 29, whereby the drift voltage can be removed and only the voltage output generated by the Coriolis force can be taken out.

FIG. 4 is a perspective view of an equilateral triangular vibrating gyro. Parts corresponding to those in FIG. 1 are designated by the same reference numerals. A drive signal is applied to the vibrating gyroscope to the piezoelectric elements 22 and 23 to excite the vibrator 21 in the x-axis direction of the reference numeral 50. When the oscillator 21 is rotated at the rotational angular velocity ω in the direction of the reference numeral 31, a Coriolis force is generated in the direction of the y-axis of the reference numeral 51. The vibrating direction of the vibrator itself is the direction of reference numeral 52 because it is in the composite mode of the x-axis and the y-axis. Since the piezoelectric element 23 is arranged so as to easily receive the Coriolis force in that direction, the Coriolis force can be detected with high sensitivity. Reference numeral 55 indicates a support pin of the vibrating gyro.

FIG. 5 is an electric circuit diagram of the circuit block 30 shown in FIG. Parts corresponding to those in FIG. 1 are designated by the same reference numerals. A drive signal from an operational amplifier 60 is applied to the piezoelectric elements 22 and 23 of the equilateral triangular vibrating gyro sensor. The piezoelectric element 24 is used for feedback and is input to the operational amplifier 60 to form an oscillation circuit. Further, the drive signal from the operational amplifier 60 is phase-corrected and applied to the piezoelectric elements 22 and 23. Further, the piezoelectric elements 22 and 23 also serve for detection, and the outputs thereof are input to the full-wave rectifier circuits 27a and 27b, respectively.

FIG. 6 shows a full-wave rectification circuit 27a shown in FIG.
27b shows an electric circuit diagram of 27b. Full-wave rectifier circuits 27a, 27
The absolute value of b can be output as a voltage of the same polarity regardless of the polarity of the input voltage eIN. The operational amplifier 70 and the diodes D1 and D2 form an inverting ideal diode. The signal of reference numeral 72 is input voltage eI
When input as N, the output of reference numeral 73 is obtained by inverting and rectifying the point eQ. This output is input to the operational amplifier 71 forming the inverting addition circuit via the resistor R4. On the other hand, the input voltage eIN is directly input to the operational amplifier 71 via the resistor R3. A full-wave rectified output of reference numeral 74 can be obtained at the output eO obtained by adding both inputs of the operational amplifier 71. Vref is input as a reference voltage to one input of the operational amplifiers 70 and 71.

FIG. 7 is a block diagram showing a schematic electrical configuration of a signal processing circuit in an equilateral triangular vibrating gyroscope according to another embodiment of the present invention. This embodiment is similar to the embodiment shown in FIG. 1, and the corresponding parts bear the same reference numerals. The piezoelectric elements 22 and 23 on the left and right sides of the vibrator 21 of the equilateral triangular vibrating gyroscope are used for driving, and the remaining piezoelectric elements 24 on one side are used for feedback, and the output thereof is input to the oscillation circuit 25. Further, the piezoelectric elements 22 and 23 on the two right and left sides are also used for detection. A drive signal is applied to the piezoelectric elements 22 and 23 from the oscillation circuit 25 via the phase correction circuit 26 to excite the vibrator 21. When the oscillator 21 is rotated in the direction of reference numeral 31 in that state, the voltage generated by the Coriolis force proportional to the rotational angular velocity is superimposed on the drive signal. In addition to the voltage generated by the Coriolis force, the drift voltage is also superimposed on the drive signal.

The output voltage of the piezoelectric element 23 at this time is shown in FIG.
Shown in. The point to be noted here is that the first wave 90 of the output voltage is
, The drift voltage is superimposed on the + side of the drive signal,
In the second wave 91 of the output voltage, the drift voltage is superimposed on the − side of the drive signal. In this case, the reference voltage Vref
If Vrefd 93, which is obtained by adding a drift voltage component to 92, is set as the reference voltage, the drift voltage is canceled. That is, if the output voltage of the piezoelectric element 23 is AC-coupled with Vrefd93, the drift voltage can be removed.

FIG. 9 shows an alternating current (abbreviated as “AC”) coupling circuit 8.
It is an electric circuit diagram of a bootstrap used for 0a and 80b. In this circuit, the AC output signal of the piezoelectric element and the drift voltage are AC-coupled. Further, since the input impedance of this circuit is set to a very high value, AC coupling can be performed without affecting the current of the external element such as the piezoelectric element on the input side.

FIG. 10 shows the output R signal 10 of the piezoelectric element 23.
3 is a diagram showing the relationship between 0 and the output L signal 101 of the piezoelectric element 22. FIG. FIG. 10A is a diagram showing an ideal state in which there is no phase difference between the R signal 100 and the L signal 101 when the vibrator 21 is in the rotating state. When differential amplification is performed in this state, a differential output 103 of the R signal 100 and the L signal 101 is output.
Can be obtained. However, in reality, when the vibrator 21 is not rotating at room temperature, the phase is slightly corrected, and the R signal 100 and the L signal 101 are denoted by reference numeral 102.
Even if the phase difference between the two is set so that there is no phase difference, the phase difference occurs when the vibrator 21 is rotated. This is because a phase difference occurs due to the distribution of the R signal 100 and the L signal 101 of the Coriolis force, the temperature characteristic of the oscillator section, and the temperature characteristic of the phase correction circuit 26 when the oscillator 21 is rotating and at low and high temperatures. The relationship between the R signal 104 and the L signal 105 in FIG. Therefore, in the differential output between the R signal 100 and the L signal 101, the error of the reference numeral 106 occurs. Therefore, when the R signal 100 and the L signal 101 are full-wave rectified and smoothed, differential amplification is performed.
As shown in (c), the error due to the phase difference can be eliminated. Further, the correction of the phase becomes unnecessary, and the conversion efficiency is improved because the full-wave rectification is performed. In the example of FIG. 10C, the full-wave rectified output 110 of the R signal 100 and the full-wave rectified output 111 of the L signal 101 are smoothed to obtain outputs of reference numerals 112 and 113. When differential amplification is performed in that state, the R signal 10
A differential output 114 of 0 and the L signal 101 can be obtained.

From the above, as shown in FIG. 7, the R signal 1
00 and L signal 101 are output to AC coupling circuit 80a,
80b, full-wave rectifier circuits 27a and 27b, and smoothing circuit 8
When differential amplification is performed by the differential amplifier circuit 28 via 1a and 81b, respectively, the drift voltage can be removed,
The phase correction of the R signal and the L signal becomes unnecessary. Also, R
A potentiometer and resistance adjustment are generally required in the amplitude correction of the signal and the L signal. However, the life of the potentiometer, vibration resistance or temperature characteristics of resistance,
Also, considering that the amplitude difference with respect to the drive signal is small, it is difficult to adjust the amplitude of the R signal 100 and the L signal 101. Therefore, as shown in FIG. 7, if the amplitude is adjusted after AC coupling, full-wave rectification and smoothing, the amplitude can be adjusted without being affected by the drift voltage and the phase difference. In this case, only the variation of the output voltage coefficient of the piezoelectric element and the influence of the temperature characteristic remain, so that the adjustment accuracy is improved, and the amplitude correction circuit 82 can perform the amplitude correction by the rough adjustment.

The simple vibrator shape of the equilateral triangular vibrating gyro has high productivity, small size and high sensitivity.
Resistant to vibration and shock. Further, the angular velocity can be known simply by placing it on an arbitrary place of the moving body such that the center of rotation always moves, without being affected by the mounting position and direction. Therefore, it has a wide range of applications and is used in a wide range of applications such as navigation systems and 4WS (four-wheel steering) for preventing tilt due to cross wind, attitude control of ships and train antennas, robots, and automated guided vehicles.

[0021]

As described above, according to the present invention, by using a pair of full-wave rectifier circuits and a differential amplifier circuit in the signal processing circuit of the equilateral triangular vibrating gyro, the output voltage of the piezoelectric element is reduced. The drift voltage can be removed.

Further, according to the present invention, by using a pair of AC coupling circuits, a pair of full-wave rectification circuits, a pair of smoothing circuits, and an amplification circuit in the signal processing circuit of the equilateral triangular vibrating gyro. The drift voltage can be removed from the output voltage of the piezoelectric element. Furthermore, it is not necessary to correct the phase of the output voltage of the piezoelectric element, improving the adjustment accuracy of amplitude correction,
Correction can be performed by rough adjustment. Therefore, a highly accurate vibration gyro signal processing circuit can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic electrical configuration of a signal processing circuit in a vibrating gyro having an equilateral triangular sound piece according to an embodiment of the present invention.

2 shows the voltage output of the piezoelectric element in the signal processing circuit of FIG.

3 shows inputs and outputs in the differential amplifier circuit 28 of FIG.

FIG. 4 is a perspective view of an equilateral triangular vibrating gyro.

5 is an electric circuit diagram of a circuit block 30 shown in FIG.

6 is an electric circuit diagram of a full-wave rectifier circuit 27 shown in FIG.

FIG. 7 is a block diagram showing a schematic electrical configuration of a signal processing circuit in a vibrating gyro of an equilateral triangular sound piece according to another embodiment of the present invention.

8 shows the voltage output of the piezoelectric element in the signal processing circuit of FIG.

9 is an electric circuit diagram of the AC coupling circuit 80 shown in FIG.

10 is a diagram showing a relationship between an output signal R and an output signal L of a piezoelectric element in the signal processing circuit of FIG.

FIG. 11 is a block diagram showing a schematic electrical configuration of a signal processing circuit in a conventional equilateral triangular vibrating gyro.

[Explanation of symbols]

 21 oscillator 22-24 piezoelectric element 25 oscillation circuit 26 phase correction circuit 27a, 27b full wave rectification circuit 28 differential amplification circuit 29 direct current amplification circuit 80a, 80b AC coupling circuit 81a, 81b smoothing circuit 82 amplitude correction circuit

Claims (2)

[Claims] 1. A signal processing circuit of a vibrating gyroscope, which detects an output voltage from a left and right piezoelectric element of an equilateral triangular vibrating gyro by a Coriolis force and detects an angular velocity corresponding to the Coriolis force. A vibration gyro signal including a pair of full-wave rectifier circuits for full-wave rectifying the output voltage from each piezoelectric element and a differential amplifier circuit for amplifying the difference between the output voltages from each full-wave rectifier circuit. Processing circuit. 2. A signal processing circuit for a vibrating gyroscope, which detects the output voltage from the left and right piezoelectric elements of an equilateral triangular vibrating gyro by the Coriolis force and detects the angular velocity corresponding to the Coriolis force. A pair of AC coupling circuits for extracting the AC components of the output voltage from the piezoelectric element, a pair of full-wave rectification circuits for full-wave rectifying the AC output voltages from the AC coupling circuits, and a pair of full-wave rectification circuits. A signal processing circuit for a vibrating gyroscope, comprising a pair of smoothing circuits for respectively smoothing the outputs of the above, and a differential amplifier circuit for amplifying a difference between output voltages from the respective smoothing circuits.