JPH0378567B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an error correction device for a gyro compass used as a direction reference for ships.

[Conventional technology]

Referring to FIG. 2, as an example of a gyroscope to which the error correction device according to the present invention can be applied,
Gyroscope compass by the applicant (Japanese Patent No.
885730).

In Figure 2, 1 is a gyro case with a built-in gyro rotor that rotates at high speed.
This is made into a liquid-tight structure. 2 is a tank-like container surrounding the gyro case 1; 3 is the gyro case 1;
The upper end thereof is fixed to the tank 2 and the lower end thereof is fixed to the gyro case 1 with a suspension line supporting the . 4N, 4
S, 5N and 5S are the primary and secondary sides of the non-contact displacement detection device 6, respectively, and the primary sides 4N and 4S are, for example, the surface of the gyro case 1, and the intersection with the extension of the gyro's spin axis, that is, the north of the gyro. and the south side respectively. On the other hand, the secondary sides 5N and 5S are attached to the corresponding positions of the primary sides 4N and 4S of the tank 2. 7
The tank 2 is filled with a highly viscous liquid such as damping oil. A pair of horizontal axes 8 are located at positions (east and west) orthogonal to the equatorial spin axis of the tank 2,
Attach one end of 8′ and attach their other ends to horizontal ring 12.
It is rotatably fitted into bearings 13, 13' provided at corresponding positions. 10 is a horizontal tracking servo motor, which is attached to the horizontal ring 12. One horizontal axis 8
A horizontal gear 9 is attached to the servo motor 10, and this is meshed with a horizontal pinion 11 attached to the rotating shaft of the servo motor 10. Gimbal shafts 14 and 14' are respectively attached to the horizontal ring 12 at positions orthogonal to the horizontal shaft bearings 13 and 13', and these are mounted to corresponding positions of the follower ring 16 and gimbal shaft bearings 15 and 15', respectively. Rotatably fit. Follower shafts 17, 17' are mounted above and below the follower ring 16, and their free ends are rotatably fitted into follower shaft bearings 25, 25' provided at corresponding positions on the plate 24. A direction gear 21 is attached to one of the following shafts 17. Reference numeral 19 denotes an azimuth following servo motor attached to the board 24, and 20 an azimuth pinion attached to its rotating shaft, which meshes with the azimuth gear 21. 22 is a compass card, which is attached to the follower shaft 17'. 23
is a base plate attached to the upper surface of the board 24 so as to correspond to the compass card 22, and by the base line 26 drawn in the center and the compass card 22,
Read the course of the navigation vehicle equipped with this device.

Reference numeral 28 denotes an azimuth transmitter which is attached to the rotor of the azimuth gear 21 and meshed with a pinion 29, which transmits the heading direction of a vessel such as a ship to the outside.

Next, a specific example of the above-mentioned non-contact displacement detection device 6 will be explained with reference to FIG. 3. Figure 3 is N (north)
This is one set of sides taken out. As shown in the figure, the primary side 4N is made into one primary side coil, and its winding is in a plane perpendicular to the spin axis of the gyro, and is usually excited by an alternating current shared with the gyro power supply PS, and is indicated by the dashed line. Create an alternating magnetic field indicated by a1 and a1. The secondary side 5N also has four rectangular coils 5.
Consisting of NW, 5NE, 5NU, and 5NL, a pair of coils 5NW and 5NE are arranged in parallel in the horizontal direction,
The other pair of coils 5NL and 5NU are arranged vertically. The winding start of the coil pair 5NW, 5NE and the winding start of the coil pair 5NU, 5NL are connected to each other. Now, considering the case where the primary coil 4N, that is, the gyro case 1 is located at the center of the secondary coil 5N, that is, the tank 2, each of the four secondary coils 5NW, 5NE, 5NU, 5NL, As the magnetic flux from the primary coil 4N passes through, a corresponding voltage is induced in each of the four coils.
The magnetic flux changes in the next coil are almost the same, and each coil pair is differentially connected as described above, so no voltage is generated at the output terminals 2-1 and 2-2. . For example, if we consider the case where the primary coil 4N is biased to the east (E in the figure), the magnetic flux passing through the coil 5NE increases, and the magnetic flux passing through the coil 5NW decreases, so the output terminal 2- A voltage is generated at terminal 1, but there is no output at terminal 2-2. On the other hand, if the primary coil 4N deviates to the west (W in the same figure), the coil 5NW
The induced voltage of coil 5NE increases, the induced voltage of coil 5NE decreases, and a voltage with the opposite phase to that in the case of eastward bias is generated at terminal 2.
-1 occurs. In this case, coil 5NU, 5
Since NL is arranged in the vertical direction, no voltage is generated at its output terminal 2-2, as described above. On the other hand, in response to the vertical displacement of the primary coil 4N, the horizontally arranged coil 5
Although no voltage is generated in NW and 5NE, voltage is generated in the coils 5NL and 5NU arranged in the vertical direction, so an output voltage is generated at the terminal 2-2. That is, with the structure shown in FIG. 3, displacement of the N end of the gyro case 1 relative to the tank 2 in the east-west direction and the vertical direction can be detected.

FIG. 4 shows only the east-west detection device, and is a layout diagram of the gyroscope case 1 viewed from above. In other words, the primary coil 4S is connected to the displacement detection device on the S side.
and secondary coils 5SE and 5SW, and when the gyro case 1 deviates to the east, the coil 5
The magnetic flux passing through SE increases, the magnetic field of coil 5SW decreases, and a voltage is induced at terminal 3-1, and the phase of this voltage is made equal to that of the voltage generated at terminal 2-1 of coils 5NW and 5NE. . In addition, as shown in Fig. 3, coils 5SE, 5SW and coils 5NE,
5NW is further differentially connected, when the gyro case 1 is displaced in the east-west direction, there is no voltage generated at the terminal 3-2, but the gyro case 1 is connected to the vertical axis 0 (perpendicular to the drawing). ), an output voltage whose phase is reversed by 180 degrees is generated at the terminal 3-2 depending on the direction of rotation. This output voltage is applied to the control winding of the azimuth servo motor 19 via (or without) a servo amplifier 30. The rotation of the servo motor 19 is transmitted to the tank 2 via the azimuth pinion 20, the azimuth gear 21, the follower ring 16 and the horizontal ring 12, and the tank 2 is controlled so that the angular displacement around the vertical axis is zero. be done. That is, the gyro case 1
No matter what direction it takes, this servo system causes no torsion in the suspension line 3, so that no disturbance torque is applied to the gyro with respect to the vertical axis. In addition, in Figure 4, 3-
3 is a signal generator for error correction, which generates a voltage corresponding to the speed or latitude of the ship, shifts the tracking of the azimuth tracking system, twists the suspension line 3, and applies torque around the vertical axis of the gyro to correct the error. I do.

Figure 5 shows the horizontal tracking system, with secondary side 5
N and 5S coils 5NU, 5NL and 5SU, 5
SL is connected differentially as mentioned above, and for this reason, the terminals 4-1 of coils 5NU and 5NL are
For vertical translational movement of the gyro case 1 relative to the tank 2, no output voltage is generated, but for angular movement about the horizontal axis, a voltage is generated at the terminal 4-1, which is applied via the servo amplifier 31. (or without) the control winding of the horizontal tracking servo motor 10. The rotation of the horizontal follow-up servo motor 10 rotates the tank 2 via the horizontal pinion 11 and the horizontal gear 9, thereby making the angular displacement of the tank 2 equal to zero.

Figure 6 schematically shows the inside of the tank 2, indicating the extension of the spin axis of the gyro in the gyro case 1 on the north end A side (located on the gyro case 1).
is raised by an angle θ with respect to the horizontal plane H-H'. Here, the center of gravity of the gyro case 1 is
O ₁ , the connection point Q between the suspension line 3 and the gyroscope case 1;
The connection point between the suspension line 3 and the tank 2 is P, the center of the tank 2 is _O2 , and when the spin axis of the rotor in the gyro case 1 is horizontal (θ=O), _O1 and _O2 are coincident. It is assumed that there is Also, point A to the north end, B and A
A′,
Let B' be the point on tank 2 corresponding to A and B. Since the suspension line 3 actually has bending rigidity,
Since it exhibits a deflection curve like the dotted line in the figure, tank 2
The axial movement of the gyro case 1 relative to both ξ (O ₂
~O ₁ ) should decrease very slightly, but in practical design this effect is extremely small, and here we will proceed with the explanation assuming that the suspension line 3 is completely flexible. As mentioned above, due to the action of the servo system, points A' and B' on the tank 2 and points A and B on the gyro case 1 are
Since B is always on a straight line,
Like the gyro case 1, the tank 2 is also inclined by θ with respect to the horizontal plane H-H'. Now, assuming that there is no external acceleration, no external force is acting on the spin axis direction of the gyro case 1, so the suspension line 3
coincides with the vertical line. Let T be the tension of the suspension line 3,
If the residual weight of the gyro case 1 after removing the buoyant force due to the damper fluid 7 is mg, then the tension T of the suspension line 3 creates a moment M around the point _O1 as follows: M=Tr sin θ=mg r sinθ, and this is the gyro torque. It will join the rest of its horizontal axis (perpendicular to the plane of the paper through O ₁ ). Here, r is the distance between the center of gravity _O1 of the gyro case 1 and the connection point Q between the suspension line 3 and the gyro case 1, as shown in the figure. That is, with this method, it is possible to ``apply a torque around the horizontal axis of the gyro that is proportional to the inclination of the spin axis with respect to the horizontal plane'', just like the conventional gyro compass.
A gyroscope compass can be obtained by selecting the distance r, the residual mass mg, and the angular momentum of the gyroscope, and setting the period of the northing motion to between several tens of minutes and hundreds of tens of minutes.

Next, the damping device in the above-mentioned gyro compass will be explained. Its basis is the principle of ``applying a torque around the vertical axis of the gyro that is proportional to the inclination of the gyro's spin axis with respect to the horizontal plane'', which is already used in many conventional gyro compasses. This concerns its practical means. When the spin axis of the gyro compass configured as explained in connection with FIGS. 2 to 6 is inclined by θ with respect to the horizontal plane H-H', the tank 2
is also tilted by the same angle θ as the gyro in the gyro case 1 due to the action of the horizontal tracking system, and the gyro case 1 moves by O ₁ − O ₂ = ξ in the direction of B' until the suspension line 3 coincides with the vertical line. and stand still. That is,
The gyro inclination angle θ and the amount of movement ξ of the gyro case 1 relative to the tank 2 in the spin axis direction are in a completely proportional relationship. Therefore, by electrically detecting this amount of movement ξ, biasing the follow-up position of the vertical follow-up system in accordance with this detected amount, and twisting the suspension line 3, a desired damping effect can be provided.

FIG. 7 is a specific example of implementing the above-mentioned principle, and is an embodiment applied to the example of FIG. , 5S, two new coils 14-2, 14-3 are newly installed on the north and south sides of the coils 14-2 and 14-3, respectively, so that their respective winding frame surfaces are parallel to the conventional two pairs of coils 5NE, 5NW and 5SE, 5SW. After additionally installing coils 2 and 14-3 and connecting them differentially, connect the output ends 14-1 of coils 14-2 and 14-3 additively to the signal terminal 3-2 of the vertical tracking system. After that,
Azimuth servo motor 19 via servo amplifier 30
control winding. In this case, the vertical tracking system will cause a servo error by the signal voltage at the terminal 14-1 which is proportional to ξ, and the tank 2 and the gyro case 1 will have a deviation angle by the signal at the terminal 14-1. Therefore, the suspension wire 3 is twisted in proportion to ξ, and since this twisting torque is proportional to ξ, it is proportional to the inclination θ of the gyro spin axis, and can provide a damping effect to the gyro.

FIG. 8 shows the motion of the spin axis of the above-mentioned gyroscope spin axis in block diagram form using the Laplace operator and the transfer function, with the azimuth error φ from the true north of the north end A of the gyroscope spin axis and the inclination angle θ as variables. This is expressed in In the figure, g is the gravitational acceleration, R is the radius of the earth, Ω is the angular velocity of the earth's rotation, H is the angular momentum of the gyroscope, λ is the latitude of that point, and τ _G is the motion of the gyroscope case 1 in the spin axis direction with respect to the tank 2. The time constant when approximated as the next lag,
K is the designated north constant mrg, μ is the damping constant, the torque generated by twisting the suspension line 3 for a unit inclination angle θ, α _N is the acceleration acting on the gyroscope case in the north-south direction due to the ship's motion, V _N is the ship's north-south velocity.

The sum of the inclination angle θ of the gyro and the north-south acceleration divided by the gravitational acceleration is the value of the gyro case 1 and tank 2.
tank 2
Create the displacement ξ of the gyroscope case 1 in the north-south direction with respect to (is the actual displacement ξ and the length a of the suspension line 3
(It is made dimensionless by dividing it by ).

The torque K51 around the horizontal axis, which is multiplied by the designated north constant K (i.e. mrg), acts around the horizontal axis of the gyro case 1 together with the vertical component Ωsinλ of the earth's rotational angular velocity Ω52, causing azimuth movement around the vertical axis, An orientation error φ occurs. The azimuth error φ multiplied by the horizontal component Ωcosλ53 of the earth's rotational angular velocity Ω is input as an angular velocity input around the horizontal axis 54 of the gyro, producing a gyro inclination angle θ.

The above is the part called the pointing north loop of the gyroscope, and since there are two poles expressed as 1/S in the loop, it is an oscillating solution. The torque μθ around the vertical axis, which is ξ multiplied by the damping constant μ, is
Together with the equivalent angular velocity V _N /R obtained by dividing the ship's north-south velocity V _N by the earth's radius R, it is input to the gyroscope element 54 around the horizontal axis to reduce the gyroscope inclination angle θ,
It is called a damping loop because it can have the effect of damping the above-mentioned pointing north motion.

The north-south velocity V _N is the azimuth error φv proportional to the latitude sec expressed by the following formula with respect to the above-mentioned north loop.
give rise to

θ _v =V _N /RΩcosλ=VcosC/RΩcosλ where C is the heading angle.

Figure 9 shows that the ship has been traveling straight for a long time with a course of 0°, and the gyro compass is statically fixed at the speed error φv ₁ at that time. At time t ₁ , the ship turns 180°, and then the ship returns to a course of 180°. This figure shows the motion of the gyro when it travels straight, and the effects of the basic acceleration of the gyro can be deduced in general cases.

The azimuth change φB caused by the acceleration between times t ₁ and t ₂ is proportional to the change in the north-south speed of the ship before and after the acceleration is applied. φB is called the varistorage amount. The method of designing this φB to be equal to the difference in velocity error before and after acceleration is an important condition called Schuler tuning in a gyroscope, and corrects the influence of acceleration in the form of velocity error (this Due to the conditions, the gyroscope's north pointing period is long, 1 to 1.5 hours). That is, φB = φv ₁ - φv In _{the two} places, the varistake amount φB is a function of the speed difference, but the difference in speed error is also a function of latitude as shown in the above equation, so the conditions of the above equation are as follows. Strictly speaking, this only holds true at a specific latitude (referred to as the reference latitude); at other latitudes, the error of Δφ shown in Figure 9 will occur immediately after turning, and then the error will occur according to the basic motion characteristics of the gyro compass. , the process of performing vibration damping motion toward the speed error φv ₂ after turning is taken.

[Problem that the invention seeks to solve]

The gyroscope compass corrects the influence of acceleration as a speed error using a method called Schuler tuning, which eliminates it so that it does not pose a problem for general ships in practice, but it is useful for survey ships, observation ships, and high-speed ships. , or in the case of military ships, etc., more accurate orientation is required, but because the Schuler tuning condition is not strictly satisfied at latitudes other than the reference latitude, immediately after acceleration motion,
The drawback is that some errors occur and accurate orientation cannot be obtained.

Therefore, the present invention can easily correct errors in the gyroscope caused by accelerated motion of a navigation vehicle such as a survey ship or high-speed boat that requires accurate orientation.
The present invention aims to provide an error correction device for a gyro compass.

[Means for solving problems]

An error correction device for a gyro compass that solves the above problems according to the present invention includes: a gyro case containing a gyro whose spin axis is approximately horizontal; a support device that supports the gyro case with three degrees of freedom; a pointing device that applies a torque to the gyro case that is proportional to the inclination of the horizontal plane of the spin shaft; a tilt converter that converts a signal corresponding to the inclination of the gyro case with respect to the horizontal plane of the spin axis into an electrical inclination angle signal; An error correction device is provided for inputting the inclination angle signal of the inclination converter and the speed signal of the navigation object to a gyro compass that includes an azimuth transmitter that transmits the direction of the spin axis with respect to the navigation object. The azimuth error caused by the motion of the azimuth oscillator is estimated, and the output error of the azimuth oscillator is corrected using the estimated azimuth error.

[Effect]

An error correction device is provided that receives as input a north-south inclination signal proportional to the inclination angle of the spin axis of the gyro compass with respect to the horizontal plane and a speed signal of the navigation object. By estimating the azimuth error of the compass, inputting the estimated azimuth error into the azimuth oscillator, and correcting the azimuth transmission output, errors caused by the movement of the navigation object are corrected.

〔Example〕

Hereinafter, an example of the error correction device for a gyroscope according to the present invention will be explained with reference to FIG. This is the gyroscope compass shown. Therefore, a gyro compass to which the present invention is applied is not shown in FIG.

FIG. 1 is a block diagram showing an embodiment of a gyro compass error correction device 90 according to the present invention. Heading direction from the direction transmitter 28 shown in FIG.
C' and a log speed signal V' from a speedometer (log) of the ship (not shown) are supplied to a north-south speed calculation section 100 and a north-south acceleration calculation section 101, and from these, a north-south speed signal V _N ' and a north-south acceleration are obtained. A signal α _N ′ is generated, and these signals V _N ′ and α _N ′ are input to the disturbance input calculation unit 102 along with the latitude information λ′ of the current location of the ship, and the output Du is input to the state variable estimation calculation unit 103. do.
In addition to the above-mentioned inputs, the state variable estimation calculation unit 103 receives a signal FZ obtained from its own output Z through the control coefficient calculation unit 104, an axial movement amount (north-south tilt signal) from the compass system shown in FIG.
A signal Gy obtained by passing y= through the observed value input calculation unit 105 is input.

The output Z of the state variable estimation calculation unit 103 is inputted to the estimated azimuth error calculation unit 106 together with the above-mentioned north-south tilt signal to generate a compass azimuth error correction signal φ′,
This is output to the direction transmitting section 107. The heading transmitter 107 adds the heading error correction signal φ' to the heading signal C' from the heading transmitter 28, and outputs the true heading C.

The error correction device 90 described above is based on an error estimation method called an observer, and the procedure of the method will be described below.

The motion of the gyro compass shown in FIG. 6 is expressed by the following differential equation with respect to a state variable matrix x whose elements are the north-south tilt signal, the azimuth error φ, and the gyro tilt angle θ.

x = Ax + Bu ... (1) y = Ex ... (2) In the above equation, A is the 3 x 3 system matrix, B is the 3 x 3 disturbance input matrix, and u is the north-south acceleration α _N and the earth's angular velocity. Vertical component Ωsinλ of Ω,
The disturbance input has the north-south velocity V _N as a component, y is the observation value vector, and since only the north-south tilt can be observed with the gyroscope shown in Figure 6, y==x(1), E is the observation coefficient and generally Although it is a matrix, the 6th
In the system shown in the figure, E=1 as a scalar quantity.

The system matrix A is divided into observable columns as follows.

x = A ₁₁ A ₁₂ A ₂₁ A ₂₂ x + B ₁ B ₂ ^u ... (3) y = ... (4) Here, A ₁₁ and B ₁ are each scalar quantities.

With the disturbance u as input, the following equation holds true regarding the state variable estimated value Z corresponding to each element of the state variable x.

Z = FZ + Gy + Du ... (5) where F is a 3x3 estimated gain matrix and G is an input matrix to the observer.

Also, using the matrix L determined from the responsiveness (time constant a) of the observer system expressed by equation (5), each matrix in equation (5) is F=A ₂₂ −LA ₁₂ ...(6) G= It is given by F+A ₂₁ −LA ₁₁ ...(7) D=B ₂ −LB ₁ ...(8).

In equation (5), the disturbance input equivalent to the compass system
The part that creates Du is the output of the north-south velocity calculation unit 100
This is a disturbance input calculation unit 102 which receives as inputs V _N ′, the output α _N ′ of the north-south acceleration calculation unit 101, and the latitude λ′.
In addition, the observation value input calculation unit 105 generates Gy from the north-south slope signal, and the control coefficient calculation unit 104 generates Fz.
This is the part that generates and feeds back to the state variable estimation calculation unit 103. The orientation error correction signal φ' can be obtained as follows: φ'=Z+Ly =Z(2)+L(2)...(9) This is performed by the estimated orientation error calculation unit 106, and the output φ' is calculated as the orientation. Transmission part 1
07 along with the ship's heading C', and the correct ship's heading C is output.

In the above explanation, the present invention has been described with respect to the Sperry type gyro compass which adopts the simplest vertical axis damping method as shown in FIG. In addition, it can be immediately applied to a method that eliminates latitude errors and a horizontal axis damping method.In short, it is a type of compass that outputs a signal corresponding to the inclination angle θ of the spin axis with respect to the horizontal plane. All of these are applicable to the gyro compass.

Furthermore, when the specific gravity and viscosity of the damping oil 7 shown in FIG. 2 change with temperature, the designated north constant K and the north-south time constant τ _G shown in FIG.
If there is a difference between the system matrix A and the system matrix A, an error will occur in the direction estimation, making it impossible to correct the error correctly.

A temperature detection element is inserted into the gyro compass to compensate for this, and the signal T thereof is input to the observed value input calculation unit 105 and state variable estimation calculation unit 103 in the error correction device 90 shown in FIG. By correcting the correction value of Tux A, the influence of temperature change can be removed.

〔Effect of the invention〕

An error correction device is provided that receives as input a north-south inclination signal corresponding to the inclination angle of the spin axis of the gyro compass and a log signal proportional to the speed of the ship, and in this device, the acceleration error and speed error of the gyro compass are estimated and calculated. At the same time, by adding this heading estimation error to the heading signal of the heading transmitter and outputting it, it corrects the error of the gyroscope caused by the movement of the ship at any latitude except near the poles on the earth. Therefore, a high-performance gyro compass can be obtained without making any mechanical modifications to the gyro compass body.

Also, due to temperature changes, the designated north constant K and north-south time constant τ _G
By installing a temperature sensor in the mechanical part of the compass and using this output temperature signal to correct the value of the system matrix A in the error correction device, the direction estimation error caused by the fluctuation of the compass is corrected. It is possible to eliminate the occurrence of correction errors due to temperature changes.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
The figure is a partially cutaway schematic diagram of an example of a gyro compass to which the present invention is applied, FIG. 3 is a schematic diagram of an example of its displacement detection device, and FIGS. 4 and 5 are schematic diagrams of its tracking system. Fig. 6 is an explanatory diagram of its principle, Fig. 7 is a schematic diagram illustrating an example of the vibration damping device, Fig. 8 is a block diagram showing the motion of the gyro compass, and Fig. 9 is a navigation diagram. It is a graph used to explain the error of the gyroscope due to the movement of the body. In the figure, 1 is a gyroscope case, 28 is a direction transmitter, 90 is an error correction device, 100 is a north-south velocity calculation section, 101 is an acceleration calculation section, 102 is a disturbance input calculation section, 103 is a state variable estimation calculation section, 104
105 is a control coefficient calculation unit, 105 is an observed value input calculation unit,
Reference numeral 106 indicates an estimated orientation error calculation section, and reference numeral 107 indicates an orientation transmission section.

Claims (1)

[Claims] 1. A gyro case containing a gyro with a substantially horizontal spin axis, a support device that supports the gyro case with three degrees of freedom, and a finger that applies a torque to the gyro case in proportion to the inclination of the horizontal plane of the spin axis. It consists of a north device, an inclination converter that converts a signal corresponding to the inclination of the spin axis of the gyro case with respect to the horizontal plane into an electrical inclination angle signal, and an azimuth transmitter that transmits the azimuth of the spin axis with respect to the navigation object. The gyro compass is equipped with an error correction device that inputs the inclination angle signal of the inclination converter and the speed signal of the navigation object, and estimates the azimuth error caused by the movement of the navigation object, and also corrects the error based on the estimated azimuth error. An error correction device for a gyro compass, characterized in that it corrects errors in the output of the azimuth transmitter.