JPH05264280A - Gyro device - Google Patents

Abstract

PURPOSE:To correct a bias temperature error by reading the bias temperature error from a bias error memory part in conformation to the temperature provided by a temperature sensor, and outputting and adding the correction value of the bias temperature error. CONSTITUTION:An error correcting device 70 is formed of a first A/D converter 51 for digitally converting the output obtained from a temperature sensor 40 provided near a sound or 1, a bias temperature error memory part 55 for storing a bias temperature error, and an A/D converter 53 for analoge-converting this output. The memory part 55 can store the bias temperature error to each temperature over the use temperature range and read the bias temperature error in conformation to the output of the converter 51. The output of the error correcting device 70 is added to an adder 42, and a gyro output having no bias temperature error can be provided through a filter 36.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gyro device suitable for application to, for example, a gyro device (angular velocity detecting device) using a tuning fork.

[0002]

2. Description of the Related Art Conventionally, as a gyro device of this type,
For example, there is one as shown in JP-A-63-38110. Here, an example of a conventional gyro device will be described with reference to FIGS. 4 to 9. In the conventional example shown in FIG. 4, the tuning fork 1 is composed of a vibrating mass section 1-1, which has a large mass.
1-1 and the bending portions 1-2, 1- that are respectively connected to these
2 and the base portion 1-3 connecting the free ends of the both flexible portions 1-2 and 1-2, and the both flexible portions 1-2 and 1-2 from the base portion 1-3.
The space between them is composed of a connecting portion 1-4 extending in a non-contact manner with both.

Reference numeral 80 denotes a hinge. The hinge 80 includes a central connecting portion 80-2, strip-shaped hinge portions 80-1 and 80-3 extending vertically from the connecting portion 80-2, and the two hinge portions 8.
It is composed of a base portion or an annular portion 80-4 that integrally connects and connects the free ends of 0-1 and 80-3. Hinge part 80-
1 and 80-3 are piezoelectric elements 81-1 and 81- for detecting the bending of the tuning fork 2 due to the angular velocity Ω input around the input shaft (Z-Z) of the tuning fork 1, and hence the bending of the hinge 80.
2 are fixed respectively. Also, the connecting portion 80-2 of the hinge 80
Is fitted into the U-shaped recess 1-4a of the connecting portion 1-4 of the tuning fork 1.

The base portion of the hinge 80, that is, the annular portion 80-
The openings of the cylindrical bodies 21-1 and 21-2, which are closed at one end and have substantially the same shape and the same size, are airtightly fixed to the both open ends of No. 4, respectively. In this case, the annular portion 80-4 and the tubular body 21-
The axes 1 and 21-2 are tuning fork axes or input axes (Z-
Z). Cylindrical body 21-1,
L-shaped metal fittings 23 whose bottom ends are fixed to the mounting base 2 via cylindrical elastic members 22-1 and 22-2, respectively. -1,23
-Fix to the upper end of -2.

FIG. 5 illustrates the principle of the conventional example shown in FIG.
FIG. 4 is an explanatory view for explaining the main part of the axis (Z-Z) direction of FIG.
It is seen from the direction. As shown in the figure, this gyro
When an angular velocity Ω is applied to the device around the axis (ZZ), the
Coriolis force F corresponding to this _CAre both vibration mass parts 1-1,
1-1 occurs in parallel to each other and in opposite directions.
Luk is hinged through the connecting portion 80-2 of the hinge 80.
80-1, 80-3, as shown in the figure, S-shaped bending
Give rise to shape. In this case, the piezoelectric elements 81-1 and 81-
No. 2 has the same polarization direction as shown by + and-in the figure.
Hinge parts 80-1, 80-
Since it is fixed to 3, both piezoelectric elements 81-1 and 81-
One output V by connecting 2 in parallel_P1And this is tuning fork 1
Phase output V of control device 35 to be driven_P2′ Together with the detector
By synchronously rectifying to 7, the input angular velocity Ω is detected,
Therefore, a gyro device can be obtained.

On the other hand, in order to detect the displacement of the tuning fork 1, the outputs of the displacement detectors (piezoelectric elements) 6 and 6A attached to both the bending portions 1-2 and 1-2 of the tuning fork 1 are output via the control device 35. 1
Are input to the drive elements 4 and 4A made of, for example, piezoelectric elements attached to the two flexures 1-2 and 1-2, thereby forming the self-oscillation system of the tuning fork 1.

FIGS. 6 and 7 are block diagrams showing conventional examples of a self-excited oscillation system 35A including the control device 35 shown in FIG. 4 and a detection system 7A including the detection device 7, respectively. Figure 6
The self-excited oscillation system 35A and the detection system 7A in FIG.
It is connected via 4a and 10a. In FIG. 6, 10 indicates a mechanical vibration system of the tuning fork 1, that is, a control symmetry (tuning fork system of a vibration gyro), and the transfer function is shown in the block. 11B shows the displacement detectors 6 and 6A as a whole, and G ₂ is the gain thereof.

The output voltage V _P2 of this displacement detector 11B is
It is added to the preamplifier 34 of the control device 35, and outputs the control signal V _C as the output of the control device 35 via the 45 ° phase shifter 37 and the multiplier 12, and the output V _C is the drive element 4,
A mechanical vibration system 10 is provided via a drive unit 4B composed of 4A.
And is configured to close the control loop.

The output V _P3 of the 45 ° phaser 37 is AC-DC
It is also added to the conversion unit 16. The AC-DC converter 16 is
The input voltage V _p3 is full-wave rectified, and a DC voltage corresponding to the amplitude of V _P3 is output by an appropriate smoothing circuit (not shown). V _P3
DC voltage of the reference voltage V and a set voltage V _I obtained through a setting element 15 such as a potentiometer,
The deviation signal is compared by the adder AD1, and the deviation signal is added to the deviation amplifier 18. The deviation amplifier 18 amplifies the applied deviation signal and supplies its output to the multiplier 12.

The closed loop of the self-excited oscillating system 35A including the control device 35 constructed as described above has a characteristic of divergent oscillation, produces sinusoidal oscillation, and its amplitude gradually increases. This means that the signal of one round of the loop increases while vibrating as such, so that the tuning fork 1 also vibrates mechanically at the frequency and increases the vibration. Accordingly, the input voltage V _{P3 of} the AC → DC converter 16 also increases, so that the difference between the set voltage V _I and the output voltage of the AC → DC converter 16 gradually decreases, and the deviation amplifier added to the multiplier 12 is gradually reduced. The output voltage of 18 also decreases. Therefore, the multiplier 1
The output of 2 becomes a small value due to the influence of the decrease of the output voltage of the deviation amplifier 18 with the increase of V _P3 , and eventually the signal of one loop loop and the amplitude of the tuning fork 1 are constant.

FIG. 8 is a connection diagram showing parts of the preamplifier 34 and the piezoelectric elements 6 and 6A as the displacement detector 11B of the control device 35 of the self-excited oscillation system 35A shown in FIG. For example, each of the displacement detectors 6 and 6A formed of a piezoelectric element has a tuning fork 1
Is approximately represented by a voltage source 6-1 having a voltage V _P2 = K _V2 φ proportional to the swing angle φ of each leg of C and the capacitance C ₂ . Here, the following equation is established.

[0012]

[Equation 1] φ = Φ sin ω ₀ t

On the other hand, the preamplifier 34 includes an input resistor 34-1 having a resistance value R ₂ , an operational amplifier 34-2, a resistance value R ₃ ,
It is composed of R ₄ feedback resistors 34-3 and 34-4. The following relationship exists between the input voltage V _i2 of the operational amplifier 34-2 and the output voltage V _P2 of the piezoelectric elements 6 and 6A.

[0014]

## EQU2 ## V _i2 = R ₂ C ₂ S / (R ₂ C ₂ S + 1) V _P2

However, S is a plus operator. Where V
_P2 is expressed by the following equation 3.

[0016]

[Formula 3] V _P2 = K _V2 Φ sin ω ₀ t

(Φ; vibration amplitude, ω ₀ ; angular frequency of tuning fork) By substituting this equation 3 into equation 2 and converting it into the time domain, the following equation is obtained.

[0018]

[Equation 4]

Here, δ ₂ is a phase angle determined by R ₂ C _{2 and the} like. On the other hand, the gain K _V2 of the displacement detectors 6 and 6A is given by the following equation.

[0020]

[Formula 5] K _V2 = Kh ₂ Kb ₂ / √C ₂

However, Kh ₂ is a constant determined by the size of the displacement detector, and Kb ₂ is the electric device coupling count of the displacement detectors 6 and 6A. By substituting equation 5 into equation 4, the following equation is obtained.

[0022]

[Equation 6]

In equation (6), the one that is easily affected by temperature changes is the electrostatic capacitance C ₂ of the displacement detectors 6 and 6A composed of, for example, piezoelectric elements. The formula needs to hold.

[0024]

## EQU7 ## R ₂ = 1 / C ₂ ω ₀

However, the self-excited oscillation system 35A shown in FIG.
Then, the condition of the above equation is that the amplitude φ of tuning fork 1 is topologically
45 ° ahead of (equation 6 δ ₂ =
45 °), the condition of advancing by 90 ° as an ideal oscillation system is not satisfied. Therefore, the first 45 ° phase shifter 37, which is generally composed of ordinary R and C circuits, is provided at the output stage of the preamplifier 34. There is.

Further, the vibration amplitude φ of the tuning fork 1 is 45 ° with the conditional expressions relating to the phase detectors 6 and 6A and the preamplifier 34.
The signal V _P3 advanced by 90 ° in combination with the phase shifter 37 becomes
This phase signal V _P3 is a differential value dφ / of the vibration amplitude φ of the tuning fork 1.
This corresponds to dt (rate). From equation 1, the following formula is established.

[0027]

## EQU8 ## dφ / dt = Φω ₀ cosω ₀ t

For simplicity, the gains of the preamplifier 34 and the 45 ° phase shifter 37 are set to 1, and the 45 ° phase shifter 37 sets the phase 45.
The output V _P3 of the 45 ° phase shifter 37 is expressed by the following equation.

[0029]

[Equation 9]

Further, for simplicity, the AC → DC converter 16
If the gain of the tuning fork is set to 1, the amplitude of the equation 9 becomes equal to the set voltage V _I as will be described later.
φ / dt · ω ₀ is expressed by the following equation.

[0031]

[Equation 10]

Includes controller 35 of FIG. 6 as described above.
The loop of the self-oscillation system 35A has a constant amplitude rate.
It has an automatic control function like
It also has a function to maintain the resonance frequency of the biological vibration system.
It can be seen that this is a self-excited oscillation system. The constant amplitude is
Set voltage V_IIs determined by the gain of the deviation amplifier 18 and
As the transfer function of the deviation amplifier 18 decreases as the frequency decreases,
Characteristics such that the gain is increased (for example, “proportional + integral”)
Characteristic), the steady value of the amplitude is the set voltage V _IOnly
It is decided accordingly. From this, the setting element 15 V_Ichange
By doing so, the amplitude can be arbitrarily determined.

Next, the detection system 7A shown in FIG. 7 will be described.
As described above, when the tuning fork 1 is operated and the angular velocity indicated by Ω is input around the tuning fork axis (ZZ) shown in FIG. 4, the two vibrating mass sections 1-1 and 1-1 are supplied to the two vibrating mass sections 1-1 and 1-1. Respectively, a Coriolis force F _C proportional to the product of the velocity v and the input angular velocity Ω is generated, and the tuning fork 1 is oscillated alternately around the tuning fork axis (ZZ) at the same frequency as the tuning fork 1. The angle variation of the alternating vibration is converted into an electric signal by the angular vibration detector 81 including the piezoelectric elements 81-1 and 81-2, and becomes a voltage output.

In this case, as shown in the detection system 7A of FIG.
The output voltage V of this angular vibration detector 81 _P1The preamplifier 3
Input to the didger 33 via 2 and synchronous rectification
After that, if necessary, the tuning fork is passed through the filter 36.
Ratio of angular velocity Ω input around the tuning fork axis (Z-Z) of 1
The example voltage Y is output, and the gyro device is configured.
That is, the mass of both vibration mass parts 1-1 and 1-1 of the tuning fork 1,
The product of the distances between the oscillating mass parts 1-1 and 1-1 is the proportional constant K_T
Shall be represented by. Input angle around tuning fork axis (Z-Z)
Speed Ω and proportional constant K_TAnd the speed of tuning fork 1, that is, amplitude φ = Φ
sin ω₀Coriolis force F multiplied by what differentiated t_C
Alternating torque due to ΩK_TΦω₀cos ω₀t is all tuning forks 1
The body is vibrated at an alternating angle around the tuning fork axis (Z-Z).

Reference numeral 31 in FIG. 7 is a (ZZ) axis including the tuning fork 1.
In the surrounding mechanical system, the transmission relationship is inside the block.
The declination θ of the alternating angular vibration is detected by the angular vibration detector 81.
Issue V _P1Converted to the preamplifier 32 of the detection device 7
Be done. After AC amplification with the preamplifier 32, demodulation
Data is synchronously rectified in the motor 33 and passed through the filter 36.
The voltage Y proportional to the angular velocity Ω can be output from the detection device 7.
Will be. Here, the reference signal of the demodulator 33
As a preamplifier in the control device 35 of the self-excited oscillation system 35A,
Output V_P29'in the detection device 7 of the detection system 7A
It is supplied via a 0 ° phaser 50.

Note that K _V1 is the deflection angle-voltage conversion constant of the piezoelectric elements 81-1 and 81-2 forming the angular vibration detector 81, and K ₁
Is the gain of the preamplifier 32. In the transfer function in the block 31, I is the inertia factor of the tuning fork system around the tuning fork axis (ZZ), C ₁ is the equivalent viscous drag coefficient of the tuning fork system, and K is the piezoelectric elements 81-1 and 81-2. , A torque spring constant around the tuning fork axis (Z-Z), and S indicates a Laplace operator.

Incidentally, FIG. 9 shows a piezoelectric element 81 constituting the preamplifier 32 and the angular vibration detector 81 of each of the detections 7 of the detection system 7A.
-1, 81-2 is a connection diagram showing an example, in which the angular vibration detector 81 composed of a piezoelectric element is a detection system 7A.
When it is used for, the voltage source 81-10 of the voltage V _P1 = K _V1 θ proportional to the deflection angle θ of the mechanical system 31 and the electrostatic capacitance C ₁ are approximately represented. On the other hand, the preamplifier 32 has a resistance value R
Input resistor 32-1, operational amplifier 32-2, resistance value R
_5, composed of a feedback resistor 32-3 and 32-4 of R _6. Between the input voltage V _i1 of the operational amplifier 32-2 and the output voltage V _P1 of the piezoelectric elements 81-1 and 81-2,
There is a relationship of the following formula.

[0038]

V _i1 = R ₁ C ₁ S / (R ₁ C ₁ S + 1) V _P1

However, S is a Laplace operator.

By the way, the mechanical system 31 has ΩK _T Φω ₀ co
Let s ω ₀ t be a function represented by the transfer function shown in FIG. Since the resonance point is usually selected to be lower than the resonance point of the mechanical vibration system 10 of the self-excited oscillation system 35A, the gain of the mechanical system 31 is smaller than 1 and the phase is 180 at the resonance frequency of the vibration system 10. ° Late. If the gain is K ₂ , the argument θ is given by the following equation.

[0041]

[Equation 12] θ = −K ₂ ΩK _T Φω ₀ cos ω ₀ t

Therefore, when Expression 11 is expressed in the time domain, the following expression is obtained.

[0043]

[Equation 13]

Here, δ ₁ is a phase angle determined by R ₁ , C _1, etc. On the other hand, the piezoelectric element 81 of the angular vibration detector 81-
The gain K _V1 of 1, 81-2 is expressed by the following equation.

[0045]

[Formula 14] K _V1 = Kh ₁ Kb ₁ / √C ₁

However, Kh ₂ represents a constant determined by the size of the voltage element, and Kb ₁ represents the electrical device coupling count of the voltage element. Substituting equation 14 into equation 13, the following equation is obtained.

[0047]

[Equation 15]

Among the equations (15), those that are easily affected by the temperature change are the piezoelectric element 81- which constitutes the angular vibration detector 81.
The electrostatic capacitance C ₁ is ₁ , 81-2, and the following formula must be established in order for this to be unaffected by temperature changes.

[0049]

## EQU16 ## R ₁ = 1 / C ₁ ω ₀

However, this condition advances the signal phase of the input voltage V _i1 of the preamplifier 32 of FIG. 9, that is, the output V _P1 ′ of the preamplifier 32 by 45 ° (Equation 15; δ ₁ = 45 °).
Means).

On the other hand, when the cane of the preamplifier 34 of the control device 35 of the self-excited oscillation system 35A is set to 1, its output V _P2 ′.
Is expressed by Expression 6, and assuming that the gain of the preamplifier 32 of the detection device 7 of the detection system 7A is 1, its output V _P1 ′ is expressed by Expression 15, and the phase difference between the two signals is 90 °. Therefore,
A 90 ° phase shifter 50 for inputting the output V _P2 ′ of the preamplifier 34 of the control device 35 is provided in the detection device 7, and the signal output V _F having a total phase difference of 90 ° is used as a reference signal of the demodulator 33. 33, and the reference signal V
_F and the output V _P1 ′ of the preamplifier 32 have the same phase or 18
It is configured to have a 0 ° phase.

Therefore, for simplicity, assuming that the gains of the preamplifier 32, the demodulator 33, and the filter 36 are 1, the output Y of the detection device 7 is expressed by the following equation from the equation (15).

[0053]

[Equation 17]

By substituting the expression 10 representing the vibration rate φω of the tuning fork 1 into the expression 17, the following expression is obtained.

[0055]

[Equation 18]

Equations 7 and 16 not affected by temperature change
Is applied to Equation 18, the following equation is obtained.

[0057]

[Formula 19]

From the above equation, it is known that the gyro device shown in FIGS. 6 and 7 is not affected by the temperature change.

To describe this operationally briefly, the vibration rate dφ / dt · ω of the tuning fork system is detected by the piezoelectric element 6 which detects its amplitude Φ by the action of the control device 35 so that its value becomes constant. , 6A, the gain increases, on the contrary, it decreases. On the other hand, when the gains of the piezoelectric elements 81-1 and 81-2 of the detection system 7A increase, their outputs increase. The gyro output depends on the product of the vibration rate of the tuning fork system and the output of the detection system.Therefore, by minimizing the temperature characteristics of the piezoelectric elements including the preamplifier of the tuning fork system and the detection system, the influence of temperature change can be reduced. It is possible to obtain a gyro device that does not receive the gyro.

Although the gyro having a small scale factor temperature change can be obtained by the above-mentioned configuration, in reality, a slight temperature change of the scale factor remains,
In addition, it is unavoidable that the bias itself is affected by temperature due to imbalance in production of tuning fork 1.

Reference numeral 40 in the detection device 7 of FIG.
Is a temperature sensor provided in the vicinity of, and a signal proportional to the difference between the detected temperature T _i and the reference temperature T _R , that is, ΔT = T _i −T _R is obtained from the subtractor 40A, and this signal is supplied to the gain adjuster 41. Supply. The gain adjuster 41 generates a voltage V ₃ proportional to the input signal and can adjust the proportional gain K ₂ thereof, and the output V ₃ thereof is added to the output of the demodulator 33 and input by the adder 42. Then, the output V ₃ is added to the output of the demodulator 33 by the adder 42 to compensate for the primary change of the bias value with respect to the temperature.

In FIG. 7, reference numeral 43 is a bias correction circuit for correcting a fixed bias output due to unbalance of the tuning fork 1. In this conventional example, the detection piezoelectric elements 6 and 6 of the vibration system of the tuning fork 1 are used for the gyro output.
The output transfer function of A and the piezoelectric elements 81-1 and 81 of the detection system
Pay attention to the fact that the output transfer function of -2 has a denominator / numerator relationship, and these are composed of elements of the same kind, and the input resistance value of each preamplifier is R ₁ = 1 / (C ₁ ω ₀ ). , R
_By setting ₂ = 1 / (C ₂ ω ₀ ), and by providing a 45 ° phaser 37 after the preamplifier of the self-excited oscillation system of the tuning fork, the operation as the self-excited oscillation system is secured and at the same time, the detection system 90 ° phase shifter 50 for the reference output to the demodulator
By providing the gyro device, a high-precision gyro device that does not exist in the temperature characteristics of the piezoelectric element is obtained.

[0063]

In the conventional gyro device as described above, the temperature characteristics of the piezoelectric elements including the preamplifier of the tuning fork system and the detection system are minimized so that they are not affected by the temperature. However, the temperature sensitivity of the remaining slight bias (the output when the input angular velocity is 0) was subjected to the primary correction with respect to the temperature by using the gain adjuster 41 in the detection device 7, but in reality, Since the bias output Y changes in a high order with respect to the outside air temperature, the temperature sensitivity of the bias output Y cannot be completely eliminated only by the correction by the conventional gain adjuster 41. One of the causes of the above-mentioned problems is that the temperature coefficient of capacitance of the detection piezoelectric elements 6 and 6A of the vibration system of the tuning fork 1 and the hinge 8
This may be caused by the fact that the zeros for angular vibration detection voltage elements 81-1 and 81-2 do not completely match the temperature coefficient of capacitance.

The bias is an output when the input angular velocity is 0, and if Ω in the equation 18 is set to 0, the bias output Y should be 0 regardless of the temperature, but actually, the tuning fork 1 and The vibration direction of the tuning fork 1 is not completely orthogonal to the hinge portions 80-1 and 80-3 due to problems such as the processing accuracy of the hinge 80, and a certain force is applied to the hinge portions 80-1 and 80-3.
3 is added, it is as if there is an angular velocity input. If this is called "residual vibration" in the future, the variation of this residual vibration with respect to temperature also causes the temperature sensitivity of the bias output Y.

Hereinafter, this problem will be described in some detail. A piezoelectric element 81-1 for detecting angular vibration of the hinge 80,
The capacitance temperature coefficient α ₁ of 81-2 is expressed by the following equation 20,

[0066]

[Equation 20]

The temperature coefficient α ₂ of the capacitance of the detection piezoelectric elements 6 and 6A of the tuning fork 1 is represented by the following equation 21.

[0068]

[Equation 21]

Then, assuming that the residual angular vibration Ω is constant,
If is differentiated once with respect to temperature, the following equation is obtained.

[0070]

[Equation 22]

If the electrostatic capacitances C ₁ and C ₂ of the piezoelectric elements 81-1, 81-2 and 6, 6A change linearly with temperature,

[0072]

[Expression 23] C ₁ = C ₁₀ (1 + α ₁ ΔT) C ₂ = C ₂₀ (1 + α ₂ ΔT)

(C ₁₀ : capacitance at reference temperature),
(C ₂₀ : capacitance at the reference temperature), and the following formula is obtained by substituting the formula 23 and the formula 7 and the condition 16 which is the condition without the temperature sensitivity of the scale factor due to the capacitance change into the formula 22, and rearranging them. To be obtained.

[0074]

[Equation 24]

Further, the denominator of the equation 23 and the term of ΔT ² of the numerator can be ignored, and if 1 + α ₁ ΔT≈1, 1 + α ₂ ΔT≈1, then

[0076]

[Equation 25]

This is shown in FIG. 10.

As shown in FIG. 10, the piezoelectric elements 6 and 6A for detecting the tuning fork 1 and the piezoelectric element 81-for detecting the angular vibration of the hinge 80-
If there is a difference in the capacitance temperature coefficient between 1 and 81-2, the temperature gradient (1 / Y) · (d
Y / dT) has a positive or negative slope, and as a result, the bias output Y of the detection device 7 has a quadratic distribution with respect to temperature. Further, the residual angular vibration Ω may change the vibration direction of the tuning fork 1 with respect to the hinge portions 80-1 and 80-3 due to changes in internal stress with respect to the temperature of the tuning fork 1 and the hinge 80. Is linearly changed with respect to temperature, the bias output Y is the product of the secondary change shown in FIG. 11 and the primary change of the residual angular vibration.
As shown in FIG. 12, it exhibits a three-dimensional change with respect to temperature. When the residual angular vibration Ω changes to the second-order and the third-order with respect to the temperature, the bias output Y changes to the fourth-order and the fifth-order with respect to the temperature. For this reason, when the gyro device is used for in-vehicle navigation, for example, when the operating temperature range of the gyro device is wide, there is a problem that large bias fluctuations occur particularly on the low temperature side and the high temperature side.

Further, with respect to the scale factor, due to the above-mentioned causes, a secondary scale factor error with respect to temperature may occur, and a large error may occur on the low temperature side and the high temperature side. In order to solve this, there is also a means for directly correcting the output of the demodulator 33 using a multiplier based on the temperature sensor 40, but it has to be performed for a wide range of input angular velocity, and an expensive analog multiplier is required. However, it was difficult to reduce the cost, and the accuracy was poor.

On the other hand, at a constant temperature, the input angular velocity Ω
As shown in FIG. 13, the gyro output Y with respect to the angular velocity Ω is not a straight line and may have an error. If this is called linearity error, the input angular velocity Ω
As a result, the magnitude of this nearness error also changes, which is a problem when used for navigation.

The present invention has been made in view of the above points.
It is an object of the present invention to provide a novel gyro device that eliminates the above-mentioned conventional problems.

[0082]

A gyro device according to the present invention includes, for example, a tuning fork 1 as shown in FIGS. 1 and 4, a detecting portion (hinge 80) for detecting a moment due to the Coriolis force F _C generated in the tuning fork 1, and A control device 35 for causing the tuning fork 1 to self-oscillate, a demodulator 33 for processing a signal generated from the detection unit (hinge 80), an adder 42 for inputting the output of the demodulator 33, and this detection In the gyro device having the temperature sensor 40 for measuring the temperature of the part (hinge 80), the gyro device includes a first A / D converter 51, a bias temperature error storage unit 55, and a D / A converter 53, the output of which is the adder. 42 is provided with an error correction device 70, and the output of the temperature sensor 40 is input to the first A / D converter 51, and the bias temperature error corresponding to the output is input. The bias temperature error storage unit 5
5, the data is input to the D / A converter 53, and its output is the output of the error correction device 70.

The gyro device of the present invention is, for example, as shown in FIGS.
As shown in FIG. 3, in the above description, the error correction device 70 further includes the second A / D converter 52, the first multiplier 57, the adder 56, the scale factor temperature error storage unit 54, and the second multiplier.
Of the second A / D converter 5
Input the output of the gyro to 2 and output it and the first A / D
The scale factor temperature error signal corresponding to the output of the converter 51 is read from the scale factor temperature error storage unit 54, the scale factor temperature error signal is input to the first multiplier 57, and the first A / D converter 5 is supplied.
The bias temperature error signal corresponding to 1 is read from the bias temperature error storage unit 55, and the bias temperature error signal and the scale factor temperature error calculation signal read from the scale factor temperature error storage 54 are input to the second multiplier 58. Then, the output of the multiplier and the bias temperature error signal are input to the adder 56, and the output of the adder 56 is input to the D / A converter 53.

The gyro device of the present invention is shown in FIG.
As shown in FIGS. 2 and 3, in the above description, the error correction device 70 further includes a third multiplier 59 and a linearity error storage unit 60, and corresponds to the output of the second A / D converter 52. The linearity error signal from the linearity error storage unit 60 and the second A / D converter 52
And the output of the above are input to the third multiplier 59, the output thereof is input to the adder 56, and the linearity error is corrected.

[0085]

According to the present invention, the temperature T _i obtained from the temperature sensor 40 is taken in, and the bias error storage unit 5 is accordingly read.
5, the bias temperature error is read out, and the scale factor temperature error storage unit 55 reads the scale factor temperature error according to the temperature T _i , and the calculation is performed to output the bias temperature error correction value and the scale factor temperature error correction value. Then, by adding to the adder 42, the bias temperature error and the scale fat temperature error in the gyro output Y can be eliminated.

Further, according to the present invention, the gyro output Y is taken in, and the linearity error storage unit 60 is accordingly read.
The linearity error is read out, the calculation is performed, the linearity error correction value is output, and the linearity error is added to the adder 42, whereby the linearity error can be eliminated in the gyro output Y.

[0087]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the gyro device of the present invention will be described below with reference to the drawings. The basic configuration and operation of the gyro device in this example are those in which the detection system of the gyro device shown in FIG. 7 is configured as shown in FIGS. 1, 2 and 3 in the conventional gyro device shown in FIGS. Is. Since the basic configuration and operation of the gyro device in this example are the same as those of the conventional gyro device of FIGS. 4 to 9, description thereof will be omitted, and hereinafter, FIG. 1, FIG. 2, and FIG.
Will be described.

To describe FIG. 1, FIG. 2 and FIG. 3, parts corresponding to those in FIG. 7 are designated by the same reference numerals, and detailed description thereof will be omitted.

First, referring to FIG. 1, the difference between the detection system of the gyro device shown in FIG. 1 and the detection system of FIG. 7 is that in the example of FIG. 1, the gain adjuster 41 and the bias correction circuit 43 shown in FIG. This means that the error correction device 70 is newly provided without providing.

The error correction device 70 includes a first A / D converter 51 for converting the output T _i obtained from the temperature sensor 40 provided in the vicinity of the tuning fork 1 into a digital signal, and the first A / D converter 51.
The bias temperature error storage unit 55 stores a bias temperature error corresponding to the output of the / D converter 51, and a D / A converter 53 that converts the output ΔΩ into an analog signal. The bias temperature error storage unit 55 stores the bias temperature error for each temperature over the operating temperature range, and is a part for reading the bias temperature error ΔΩ according to the output of the first A / D converter 51. .. The output V ₅ of the error correction device 70 is added to the adder 42, and the gyro output Y having no bias temperature error is obtained through the filter 36. Others are the same as those in FIG. 7.

FIG. 2 shows another block diagram of the detection system of the gyro device of the present invention. In FIG. 2, in addition to the example of FIG. 1 described above, a second A / D converter 52 and a first A / D converter are newly added.
The multiplier 57, the adder 56, the scale factor temperature error storage unit 54, and the second multiplier 58 are provided.
The output Y of the gyro is input to the second A / D converter 52, digitally converted, and the scale factor temperature error ΔSF corresponding to the output and the output of the first D / A converter 51 is stored in the scale factor temperature error storage. The scale factor temperature error signal ΔSF is read from the unit 54 and is input to the first multiplier 57.

Further, the bias temperature error signal ΔΩ corresponding to the first A / D converter 51 is read from the bias temperature error storage section 55, and the bias temperature error signal ΔΩ is read.
And the scale factor temperature error signal ΔSF read from the scale factor temperature error storage unit 54 are input to the second multiplier 58, and the output of the multiplier 58 is input to the adder 56 together with the bias temperature error signal ΔΩ. Then, the output is input to the D / A converter 53, and the output V ₅ of the D / A converter 53 is input to the adder 42. By doing so, the gyro output Y having no scale factor temperature error can be obtained. Others are the same as those in FIG. 7.

FIG. 3 shows a block diagram of still another example of the detection system of the gyro device of the present invention. In FIG. 3, in addition to the example of FIG. 2 described above, a third multiplier 59 and a linearity error storage unit 60 are newly provided, and a second A / D converter 52 is provided.
Corresponding to the linearity error signal ΔLN read from the linearity error storage unit 60 and the second A / D
The output of the converter 52 is input to this third multiplier 59, its output is input to this adder 56, and its output is D
Input to the A / A converter 53, and the D / A converter 5
The output V ₅ of No. 3 can be input to the adder 42 to obtain a gyro output signal having no linearity error. Others are the same as those in FIG. 7.

The error correction device 70 will be described in detail below by taking the error correction device of FIG. 3 including the examples of FIGS. 1 and 2 as an example. For simplicity, the gain of the filter 36 is set to 1 bias temperature error ΔΩ (temperature function) scale factor temperature error Δ
SF (temperature function) linearity error ΔLN (Ω function)
If expressed using

[0095]

Y ′ = (1 + ΔSF) (Ω + ΔΩ) (1 + ΔLN)

It becomes Decomposing this number 26

[0097]

[Equation 27] Y ′ = Ω + ΔSFΩ + ΔΩ + ΔSF · ΔΩ +
Ω ・ ΔLN + ΔSF ・ ΩΔLN + ΔΩ ・ ΔLN + ΔSF
・ ΔΩ ・ ΔLN

There is The right side of the number 27, the seventh term, the eighth
The term is so small that it can be ignored. If you rewrite it again

[0099]

[Equation 28] Y ′ = Ω + ΔSF · Ω + ΔΩ + ΔSF · ΔΩ
+ Ω ・ ΔLN

It becomes On the other hand, the error correction device 7 of FIG.
The output V ₅ of 0 is

[0101]

[Formula 29] V ₅ = Ω + Y · ΔSF + Y · ΔLN + ΔSF · ΔΩ

Next

[0103]

## EQU30 ## Y = Y'-V ₅

Substituting Eqs. 28 and 29 into Eq.

[0105]

[Expression 31] Y = Ω

Therefore, only the term proportional to the input angular velocity Ω remains, and the bias temperature error ΔΩ scale factor temperature error ΔSF and the linearity error ΔLN that is a function of the input angular velocity Ω are the functions of temperature. You can get a high precision gyro.

As described above, as shown in FIGS. 1, 2 and 3, for example, a CPU is used to perform temperature correction of all patterns, so that the bias temperature error and the scale factor temperature error are high in order of temperature. However, the correction can be done easily.

Further, when correcting the scale factor temperature error and the linearity temperature error in the related art, an expensive analog multiplier is used, for example, after the output of the demodulator 33, so that the cost cannot be reduced. Moreover, the input angular velocity of the gyro is, for example, 0.001 ° / S to 200 ° / S.
However, there was a problem with the accuracy during correction,
According to this example, since the scale factor error storage unit 54 and the linearity error storage unit 60 are provided in the CPU and the gyro signal is taken in and multiplied, the scale factor temperature error and the linearity error are corrected in the form of a bias error. The cost can be reduced without using an expensive analog multiplier, and since only the error is handled, a CPU with a small number of bits is sufficient and the calculation accuracy can be secured.

That is, as in the case of correcting the bias temperature error, only the error signal is stored, the correction signal is created and added to the demodulator output in an analog manner. Therefore, the number of bits is small and the cost is low. The CPU can be used.

As described above, according to the example of the present invention, by using the inexpensive CPU, the bias temperature error, the scale factor temperature error, and the linearity error can be eliminated, and not only the cost reduction but also the navigation etc. It is possible to realize a highly accurate gyro device as used in.
It is needless to say that the present invention can be applied to not only the above-mentioned vibrating gyro but also other gyro devices. Further, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0111]

According to the present invention, since temperature correction of any pattern can be performed, even if the bias temperature error and the scale factor temperature error are high-order with respect to temperature, there is an advantage that the correction can be easily performed.

Further, according to the present invention, since the scale factor error storage unit and the linearity error storage unit are provided and the gyro signal is taken in and multiplied to correct the scale factor temperature error and the linearity error in the form of the bias error, it is expensive. There is an advantage that the cost can be reduced without using such an analog multiplier, and a CPU having a small number of bits is sufficient because only an error amount is handled, and calculation accuracy can be secured.

Further, according to the present invention, by using an inexpensive CPU, the bias temperature error, the scale factor temperature error, and the linearity error can be eliminated, and not only the cost can be reduced but also the navigation can be used. There is a benefit of realizing a highly accurate gyro.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a detection system of a gyro device according to the present invention.

FIG. 2 is a block diagram showing an example of a detection system of the gyro device according to the present invention.

FIG. 3 is a block diagram showing an example of a detection system of the gyro device according to the present invention.

FIG. 4 is a perspective view of a conventional gyro device with a part removed.

5 is a side view of the main part of FIG. 4 viewed from the axis (Z-Z) direction.

FIG. 6 is a block diagram showing an example of a conventional self-oscillation system.

FIG. 7 is a block diagram showing an example of a conventional detection system.

8 is a diagram showing the preamplifier 34 and the piezoelectric elements 6 and 6 in FIG.
It is a connection diagram of A.

9 is a diagram showing a preamplifier 32 and a piezoelectric element 81- in FIG.
It is a connection diagram of 1 and 81-2.

10 is a diagram showing the relationship between the temperature and the first-order differential of the temperature of the bias output Y of the detection device 7. FIG.

11 is a diagram showing the relationship between temperature and the bias output of the detection device 7. FIG.

12 is a diagram showing the relationship between temperature and bias output Y of the detection device 7. FIG.

FIG. 13 shows the relationship between the input angular velocity Ω and the gyro output Y.

[Explanation of symbols]

 1 Tuning Fork 7 Detection Device 33 Demodulator 40 Temperature Sensor 70 Error Correction Device 54 Scale Factor Temperature Error Storage Unit 55 Bias Temperature Error Storage Unit 60 Linearity Error Storage Unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryohiro Cho, 2-16-46 Minami Kamata, Ota-ku, Tokyo Tokimec Co., Ltd.

Claims (3)

[Claims] 1. A tuning fork, a detecting section for detecting a moment due to Coriolis force generated in the tuning fork, a control device for causing the tuning fork to self-oscillate, and a demodulator for processing a signal generated by the detecting section. In a gyro device having an adder for inputting the output of the demodulator and a temperature sensor for measuring the temperature of the detection unit, a first A / D converter, a bias temperature error storage unit, and a D
A / A converter, which is provided with an error correction device for sending its output to the adder, inputs the output of the temperature sensor to the first A / D converter, and outputs a bias temperature error corresponding to the output to the bias temperature. A gyro device characterized in that it is read from an error storage unit, input to a D / A converter, and the output thereof is the output of an error correction device. 2. The gyro device according to claim 1,
The error correction device further includes a second A / D converter and a first A / D converter.
And a scale factor temperature error storage unit and a second multiplier, inputting the output of the gyro to the second A / D converter, and outputting the output and the first D / A converter. The scale factor temperature error signal corresponding to the output is read from the scale factor temperature error storage unit, the scale factor temperature error signal is input to the first multiplier, and the first A
A bias temperature error signal corresponding to the / D converter is read from the bias temperature error storage unit, and the bias temperature error signal and the scale factor temperature error signal read from the scale factor temperature error temperature unit are input to the second multiplier. Then, the output of the multiplier is input to the adder together with the bias temperature error signal, and the output of the adder is input to the D / A converter. 3. The gyro device according to claim 2,
The error correction device further includes a third multiplier and a linearity error storage unit, and a linearity error signal from the linearity error storage unit corresponding to the output of the second A / D converter and a second A / D converter. A gyro device, wherein the output of the / D converter is input to the third multiplier, and the output is input to the adder to correct the linearity error.