JPH11264728A - Gyrocompass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the error in acceleration or deceleration and in turning by providing a primary delay filter on a speed error compensator, and correcting the output of an azimuth transmitter after the speed error correction angle is passed through the primary delay filter. SOLUTION: An error correction part has a speed error arithmetic part 36, a time delay arithmetic part 37 and an azimuth correction part 38. The speed error arithmetic part 36 calculates the speed error correction angle. The output of the speed error arithmetic part 36 is supplied to the time delay arithmetic part 37. The time delay arithmetic part 37 substantially consists of a primary delay filter, and outputs the speed error correction angle with a time delay corresponding to its time constant. The time constant is set to a value close to the time constant of a north-indicating device. The output of the time delay arithmetic part 37 is supplied to the azimuth correction part 38, where the azimuth supplied from a master compass is corrected. The azimuth correction part 38 outputs the azimuth corrected by the speed error correction angle as the output of this gyrocompass. Thus, a gyrocompass usable for a high-speed vessel of 70-knot class can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gyrocompass for ships and the like that require high accuracy, and more particularly to a gyrocompass for ships operating at high speed.

[0002]

2. Description of the Related Art As an example of a conventional gyro compass, Japanese Patent No. 885730 owned by the same person as the present applicant.
(Japanese Patent Publication No. 52-10017). Hereinafter, the gyro compass will be described. For details, refer to the patent gazette.

As shown in FIG. 3, the gyro compass is
A gyro rotor (shown by a broken line) that rotates at a high speed, a gyro sphere or a gyro case 1 containing the gyro rotor and having a liquid-tight structure, a tank 2 surrounding the gyro case 1, and a suspension line 3 supporting the gyro case 1. And The upper end of the suspension line 3 is connected to the tank 2, and the lower end is connected to the gyro case 1. The tank 2 is filled with a liquid 7 such as high-viscosity damping oil.

The gyro case 1 and the tank 2 are each provided with a non-contact displacement detecting device 6. The non-contact displacement detecting device 6 is mounted on the outer surface of the gyro case 1.
Secondary side 4N, 4S and secondary side 5 mounted on the inner surface of tank 2
N, 5S. These primary sides 4N, 4S and 2
The secondary sides 5N and 5S are mounted on the north and south sides of the gyro, that is, mounted at positions where an extension of the spin axis of the gyro rotor horizontally arranged along the meridian direction intersects the gyro case 1 and the tank 2. Is done.

[0005] The relative displacement between the gyro case 1 and the tank 2, that is, the rotational deviation about the vertical axis and the horizontal axis of the tank 2 with respect to the gyro case 1 is detected by the non-contact displacement detecting device 6. Please refer to the above-mentioned patent publication for details.

A pair of horizontal shafts 8 and 8 ′ are mounted at a position orthogonal to the spin axis on the equator of the tank 2, and the horizontal shafts 8 and 8 ′ are arranged on a horizontal ring 1 surrounding the tank 2.
2 are mounted on the inner rings of the horizontal bearings 13 and 13 'mounted thereon. A horizontal gear 9 is mounted on one horizontal shaft 8,
The horizontal gear 9 meshes with a horizontal pinion 11 of a horizontal tracking servo motor 10 mounted on a horizontal ring 12.

The horizontal ring 12 has horizontal bearings 13, 13 '.
The gimbal shafts 14 and 14 'are mounted at positions orthogonal to
The gimbal shafts 14 and 14 ′ are attached to a gimbal bearing 1 mounted on a vertical ring 16 arranged so as to surround the tank 2.
It is mounted on the inner rings 5, 15 '. Vertical shafts 17, 17 ′ are attached to the upper and lower ends of the vertical ring 16, respectively.
Reference numerals 7 and 17 'are mounted on inner rings of vertical bearings 25 and 25' of the panel device 24.

An azimuth gear 21 is mounted on the lower vertical shaft 17, and this azimuth gear 21 meshes with an azimuth pinion 20 of an azimuth tracking servo motor 19 mounted on a board 24. A compass card 22 is mounted on the upper vertical shaft 17 '. Compass card 22
The substrate 23 is mounted so as to correspond to the above. Substrate 2
Reference numeral 3 indicates a base line 26 indicating the bow direction.

The azimuth gear 21 further includes an azimuth transmitter 35.
Is installed. The azimuth transmitter 35 transmits a bow direction indicated by the gyro compass.

An azimuth tracking system and a horizontal tracking system of the gyro compass will be described. When the tank 2 rotates around the vertical axis with respect to the gyro case 1, the amount of the rotation is detected by the non-contact displacement detecting device 6, and the voltage signal is
It is applied to the control winding of the azimuth servomotor 19. The rotation of the azimuth servomotor 19 is transmitted to the tank 2 via the azimuth pinion 20, the azimuth gear 21, the vertical ring 16 and the horizontal ring 12. Thereby, the tank 2 rotates around the vertical axis, and the relative rotational deviation between the tank 2 and the gyro case 1 around the vertical axis becomes zero.

Thus, the direction of the tank 2 always follows the direction of the spin axis of the gyro rotor by the direction tracking system. Therefore, the N-character of the compass card 22 always follows the direction of the spin axis of the gyro rotor. Therefore, the heading can be read from the deviation between the N-character of the compass card 22 and the baseline 26.

Further, since the relative rotational deviation between the tank 2 and the gyro case 1 about the vertical axis is always zero,
No torsional stress is generated in the suspension line 3 connecting the tank 2 and the gyro case 1. Therefore, with this azimuth tracking system,
No disturbance is applied to the gyro case 1.

Next, the horizontal tracking system will be described. When the tank 2 is rotationally displaced around the horizontal axis with respect to the gyro case 1, the amount of this rotational deviation is detected by the non-contact displacement detecting device 6, and a voltage signal is applied to the control winding of the horizontal servomotor 10. The rotation of the horizontal servo motor 10 is transmitted to the tank 2 via the horizontal pinion 11 and the horizontal gear 9. Thereby, the tank 2 rotates around the horizontal axis, and the relative rotational deviation between the tank 2 and the gyro case 1 around the horizontal axis becomes zero. Thus, the inclination of the tank 2 always coincides with the inclination of the gyro case 1 by the horizontal tracking system.

The gyro's finger north action will be described with reference to FIG. FIG. 4 schematically shows a state in which the gyro case 1 is disposed in the tank 2. The tank 2 is filled with a high-viscosity damping liquid 7. In a state of being immersed in water.

Here, the position of the center of gravity of the gyro case 1 is O ₁ , and the center position of the tank 2 is O ₂ . The connection point between the suspension line 3 and the tank 2 is P, and the connection point between the suspension line 3 and the gyro case 1 is Q. The central axis of the tank 2 through line PO _2. The points at which the spin axis of the gyro rotor (the dashed rectangular portion) intersects the gyro case 1 are A and B, and the points on the tank 2 corresponding to the two points A and B are A 'and B'.
Further, the horizontal plane is HH '.

When the spin axis of the gyro rotor is horizontal (θ = 0 °), the north-south line A'B 'of the tank 2 is arranged at a position aligned with the spin axis, and the position O ₁ of the center of gravity of the gyro case 1 is set. Corresponds to the center position O ₂ of the tank 2.

The spin axis of the gyro rotor is in a horizontal plane H-
Assume that the gyro case 1 is inclined at an inclination angle θ with respect to H ′, and the A side at the north end of the finger of the gyro case 1 is elevated with respect to the horizontal plane HH ′. As described above, the tank 2 rotates and tilts around the horizontal axis by following the tilt angle θ of the gyro rotor by the horizontal tracking servo system. Therefore, the center axis PO of the tank 2
₂ is inclined by an inclination angle θ with respect to the vertical line.

When no external force acts, the suspension line 3 coincides with the vertical line. Gyro case 1 by tension T of the suspension line 3
, A moment M around the center of gravity O ₁ is generated. The distance between the center of gravity O ₁ and attachment point Q of the gyro case 1 and r, if mg residue excluding weight of the buoyancy by the damper fluid 7 of the gyro case 1, the moment M is the following acting on the gyro case 1 Is represented as

[0019]

## EQU1 ## M = Trsin θ = mgr sin θ

This moment M acts as a torque on the gyro rotor around a horizontal axis (a line passing through the center of gravity O ₁ and perpendicular to the paper). In this way, it is possible to “apply a torque proportional to the angle of inclination of the spin axis with respect to the horizontal plane around the horizontal axis of the gyro”, so that fingering force is generated,
Gyro compass can be obtained. The above distance r,
By selecting the weight mg and the angular momentum of the gyro, the period of the finger north movement can be set to several tens of minutes to one hundred and several tens of minutes.

Next, a vibration damping device provided in the gyro compass will be described. The vibration damping device used in the gyro compass as described above is configured to “apply a torque about the vertical axis of the gyro in proportion to the inclination angle of the spin axis with respect to the horizontal plane”. As described above, the spin axis of the gyro rotor has the inclination angle θ with respect to the horizontal plane HH ′.
When tilted only, the tank 2
Are also inclined by an inclination angle θ with respect to the horizontal plane HH ′.

As shown in FIG. 4, the gyro case 1
Is a distance ξ (O ₁ -O _{1) in the} direction of point B ′ on tank 2 relative to tank 2 until suspension line 3 coincides with the vertical line.
₂ ) Just move. This movement amount ξ is proportional to the inclination angle θ of the spin axis of the gyro rotor with respect to the horizontal plane HH ′. Therefore, the relative movement amount of the gyro case 1 ξ
Is electrically detected, the follow-up position of the azimuth follow-up system is deviated in accordance with the detected amount, and the suspension line 3 is twisted to obtain a desired vibration damping action.

Since the suspension line 3 has a slight rigidity,
When the gyro case 1 is inclined with respect to the horizontal plane HH ′, it actually draws a bending curve as shown by a broken line. Therefore, the movement amount of the gyro case 1 in the direction of the line A′B ′ '(O
₁ -O ₂₎ is also slightly decreased. However, the suspension line 3 is sufficiently flexible, such a change in the amount of movement is small, and the effect is small in a practical design. Therefore, the description will be made here ignoring such a change in the movement amount.

The non-contact displacement detecting device 6 is provided with a displacement detecting coil for detecting the relative movement amount ξ of the gyro case 1. The output terminal of the displacement detection coil outputs a differential voltage proportional to the amount of movement の of the gyro case 1.

This voltage signal is supplied to the control winding of the azimuth servomotor 19. Therefore, the azimuth servomotor 19
This voltage signal is applied excessively to the control winding of
The azimuth following operation of the tank 2 with respect to the gyro case 1 is biased.

The tank 2 is rotationally displaced around the vertical axis so as to be deviated from the operation of the azimuth tracking system, and a torsional torque is generated in the suspension line 3. Gyro case 1
Receives a torsional torque proportional to the amount of movement の of the gyro case 1. In this way, a gyro damping action is generated.

In the gyro compass, "speed error" and "acceleration error" pose problems. The speed error is an error caused by the movement of the ship, and occurs regardless of the structure or type of the gyro compass. The fact that a ship moves along the surface of a sphere called the earth is that the ship makes a circular motion about the center of the earth. Therefore, the ship is rotating around the other rotation axis simultaneously with the rotation about the earth rotation axis. The spin axis of the gyro rotor is directed not in the direction of the earth's rotation vector but in this “composite direction of two rotation vectors”. The difference between the two is the speed error δ, which is expressed by the following equation.

[0028]

Δ = VcosC / (RΩcosλ + VsinC)

Where V is the speed of the ship, R is the radius of the earth,
Ω is the rotation angle velocity of the earth, λ is latitude, and C is azimuth.
The azimuth angle C is a deviation of the heading with respect to the true north direction (meridian), and is positive in the clockwise direction.

A description will be given with reference to FIG. FIG. 5A shows a route when a ship 80 traveling north is turning clockwise by 180 ° and the bow is turned to the south. Figure 5B shows the change in the error δ of heading phi _M indicated gyrocompass. Since acceleration error is zero when the ship is sailing at a constant speed, heading phi _M indicated gyro compass indicating the direction in which offset by the speed error δ represented by Expression 2. The speed error δ ₁ when the ship is traveling north and the speed error δ _{2 when the} ship is traveling south are given by the formulas of Equation 2 as azimuths C = 0 and C = 18, respectively.
It is obtained by substituting 0 °.

[0031]

Equation 3] _{δ 1 = V / (RΩcosλ)} δ 2 = -V / (RΩcosλ)

[0032] When the ship is in northward at a constant speed, and Nishihen angle [delta] _1, represented by the formula heading phi _M is the number 3 indicated by gyro compass, when a ship is in southward at a constant speed, The heading direction φ _M indicated by the gyro compass is settled in the azimuth direction eastward by the angle δ ₂ represented by the equation (3).

At time t _{1, the} ship 80 starts turning,
At time t _2, and has finished turning. The error of the heading φ _M indicated by the gyro compass at the end point t ₂ of the turn is larger than the angle δ ₂ represented by the equation (3), as shown in FIG. 5B. This is because an acceleration error due to turning has occurred. The amount of variation of speed error before and after the turning are referred to as ballistic error [delta] _B.

[0034]

## EQU4 ## δ _B = (δ ₂ + Δδ) −δ ₁

The heading φ _M indicated by the gyro compass is
It is to settle toward the direction that Higashihen angle [delta] ₂ expressed by the equation (3), the point at t ₃ when between the end t ₂ than the predetermined settling of turning has elapsed.

The acceleration error is a transient error that occurs when the ship accelerates / decelerates, turns, or the like, and the acceleration acts on the finger north device in the horizontal direction. The ship receives acceleration during the turn. In the above example, while turning 180 ° clockwise, the ship receives an acceleration α from south to north as a north-south component of the centrifugal force. For this reason, in FIG. 4, the gyro gyro case 1 is pushed out in the north direction (the direction from B to A), and an inclination θ = α / g proportional to the acceleration α occurs. The torque applied to the gyro case 1 by this inclination can be obtained by substituting the angle α / g into the equation (1).

[0037]

## EQU5 ## T _S = mgr sin (α / g)

R is the length of the arm of the moment, α is the northward acceleration, and g is the gravitational acceleration. This torque acts on a horizontal axis passing through the point O and perpendicular to the spin axis of the gyro, similarly to the torque generating the fingering action. Thus, the gyro spin axis produces a clockwise precession about a vertical axis (gravity axis) passing through point O.
This is the acceleration error.

[0039] Therefore, if it is possible to adjust the value of the acceleration error during turning can be ballistic error [delta] _B is set to be equal to the difference of the velocity error before and after turning.

[0040]

Δ _B = δ ₂ −δ ₁ = −2V / (RΩcosλ)

It is known that in order to satisfy this condition, the finger north period of the spin axis of the gyro rotor only needs to be about 84.3 minutes. In an ordinary ship, it takes about 3 to 4 hours from starting the gyrocompass to settling since the gyrocompass is designed so that the equation (6) is satisfied.

However, the finger north period of the spin axis of the gyro rotor is a function of the latitude λ, and the equation of Expression 6 holds only at a specific latitude λ. This latitude is called a reference latitude. The reference latitude is selected to be about 53 degrees in a normal design. This is set so as to minimize the error even if the position of the ship deviates from the reference latitude in an area at a latitude of 60 degrees from the equator which is a normal ship navigation range.

An example of a conventional method for correcting a speed error will be described with reference to FIG. Ships usually have a gyrocompass,
It has many repeater compasses in addition to the master compass. The relationship between the master compass and the repeater compass is like the relationship between the master clock and the slave clock, and the repeater compass synchronously indicates the azimuth supplied from the master compass. The ship is steered using a steering repeater compass.

Although there are various methods for correcting the speed error, an example is shown here. First, a speed error correction angle [delta] _V by the number 2 in formula. Repeater compass indicates the value obtained by correcting the heading phi _M indicated master compass by speed error correction angle [delta] _V.

As is apparent from the equation (2), when the azimuth angle C of the ship exceeds 90 degrees, the sign of the speed error correction angle δ _V changes. Therefore, the heading φ _R indicated by the repeater compass
Magnitude of heading phi _M indicated master compass and changes. Note that when the azimuth angle C of the ship is 90 degrees, that is, when the heading is facing east, the speed error correction angle δ _V is zero. Thus heading phi _M indicated heading phi _R and master compass indicated by repeater compass are equal.

[0046]

Equation 7] _{0 <C <90 ° δ V} > 0, φ R <φ M C = 90 ° δ V = 0, φ R = φ M C> 90 ° δ V <0, φ R> φ M

It should be noted that the velocity error correction angle δ _{V is} calculated by the equation (2).
Is required, the azimuth C of the ship is required, but the exact azimuth C of the ship has not yet been determined. Therefore, the heading φ _M indicated by the master compass, that is, the output of the azimuth transmitter 35 is used as the azimuth C of the ship to be substituted into the equation (2).

A description will be given with reference to FIG. In FIG.
The symbols used are defined as follows:

[0049]

Δ _V = ∠POH: Velocity error correction angle δ _A = ∠n ₀ On: Acceleration error C = ∠NOH: Actual bow azimuth of the ship φ _M = ∠nOH: Bow azimuth indicated by master compass φ _R = ∠nOP: Heading azimuth indicated by the repeater compass φ _GS = ∠nON: Gyro spin axis azimuth

FIG. 6A shows a state where the ship 80 is traveling north at a constant speed. The origin O is set at the center position of the master compass provided on the ship 80. The line segment GS represents the spin axis of the gyro rotor, and the line segment NS represents the meridian. Ship 80
Is heading north, and the heading OH of ship 80 is
N. The azimuth On _{0 of the} master compass is deviated west from the true north direction ON by an angle Δn ₀ ON.

[0051] While the ship 80 is northward at a constant speed, because the acceleration error does not occur, this west polarization angle ∠n ₀ O
N is the velocity error correction angle δ _V obtained from the calculation of the equation (2).
be equivalent to. As described above, the repeater compass indicates the azimuth obtained by correcting the azimuth angle ∠n ₀ ON of the master compass with the speed error correction angle δ _V obtained by the calculation of the equation (2). Therefore, the repeater compass indicates the true north direction ON.

FIG. 6B shows that the vessel 80 starts turning clockwise and the heading OH is located in the first quadrant of the plane coordinates. During the turn, the gyro case leans in response to the north-south acceleration α, and the gyro rotor performs a pre-session. The spin axis GS of the gyro rotor rotates clockwise from On ₀ to On by precession. Change ∠n ₀ On the spin axis GS of gyro rotor according to the pre-session is acceleration error [delta] _A.

At this time, the heading φ _M indicated by the master compass is ΔnOH. This azimuth angle φ _M = ∠nOH
Is substituted into the equation (2), the velocity error correction angle δ _{V obtained} is δ _V = ∠POH. The repeater compass has an azimuth φ _M = ∠nOH indicated by the master compass.
Is corrected by the velocity error correction angle δ _V = ∠POH. Therefore, repeater compass indicates the ∠nOP as heading phi _R. As mentioned above,
Since the azimuth angle phi _M indicated master compass is less than 90 degrees, heading phi _R indicated by repeater compass azimuth angle phi _M is smaller than indicated by master compass.

FIG. 6C shows that the vessel 80 has turned further and the heading OH is located in the second quadrant. Due to the acceleration error δ _A , the spin axis GS of the master compass
Further rotates to On, and the heading φ _M indicated by the master compass becomes ΔnOH. The heading φ _R = ∠nOP indicated by the repeater compass is a value obtained by correcting the heading φ _M = ∠nOH indicated by the master compass by the velocity error correction angle δ _V = ∠POH. As described above, since the azimuth angle phi _M indicated master compass exceeds 90 degrees, the heading phi _R indicated by repeater compass greater than the azimuth angle phi _M indicated master compass.

FIG. 6D shows a state in which the turning of the boat 80 has been completed and the heading OH has turned to the true south direction OS. The acceleration error [delta] _A of the turning, the spin axis GS master compass rotates to On, heading phi _M indicated master compass is ∠nOH = 180 ° -∠nON. The heading φ _R = ∠nOP indicated by the repeater compass is a value obtained by correcting the heading φ _M = ∠nOH indicated by the master compass by the velocity error correction angle δ _V = ∠POH.

The speed error correction angle δ _V = 旋回 PO at the end of the turn
H is equal in magnitude and opposite in sign to the speed error correction angle δ _V = ∠n ₀ ON at the start of the turn, as determined by the equation (3).

[0057]

∠n ₀ ON = V / (RΩcosλ) ∠POH = −V / (RΩcosλ)

Therefore, the following relationship is established.

[0059]

１０n ₀ ON = ∠nON = V / (RΩcosλ)

Therefore, the heading φ _M indicated by the master compass is φ _M = ΔnOH = 180 ° −Δn ₀ ON = 18
0 ° −V / (RΩcosλ). The heading direction φ _R = ∠nOP indicated by the repeater compass is a direction obtained by correcting the heading direction φ _M indicated by the master compass by a speed error correction angle ΔPOH = -V / (RΩcosλ) obtained by calculation. Therefore, the heading φ _R = ∠nOP indicated by the repeater compass is 180 °.

Thus, before and after the turn, the heading φ _M indicated by the master compass shifts westward and eastward by the speed error represented by the equation (3), but the heading φ _R indicated by the repeater compass is correctly set to 0. ° and 180 °.

[0062]

The conventional gyrocompass exhibits a predetermined excellent performance without any problem in a normal ship having a navigation speed of about 20 to 30 knots. However, in recent years, the number of high-speed ships of the 70 knot class has increased, and there are plans to establish standards for gyrocompasses mounted on high-speed ships. For example, there is a plan to establish a gyrocompass standard that can handle up to 70 knots.

In such a high-speed ship, the acceleration in the north-south direction applied to the gyro compass during acceleration / deceleration and turning becomes large, which affects the finger north device and the like. For example, when using the gyro ball type finger north device as described above, the gyro case 1 in the tank 2 may collide with the inner surface of the tank 2. In order to prevent the collision of the gyro case 1,
What is necessary is just to increase the viscosity of the liquid 7 and reduce the amount of movement of the gyro case 1 in the north-south direction. However, it has been clarified here that a new problem occurs that is not known with the conventional gyrocompass.

A description will be given with reference to FIG. FIG. 7 shows a state in which a ship traveling north is turning 180 degrees clockwise and then traveling south similarly to FIG. FIG. 7A is identical to FIG. 6A and shows a ship traveling north at a constant speed. The azimuth direction On _{0 of the} master compass is westwardly deviated from the true north direction ON by an angle 北 n ₀ ON, and the repeater compass is corrected by the west deviation angle ∠n ₀ ON to indicate the true north direction ON.

FIG. 7B shows that the ship starts turning clockwise,
The state where it is arranged in the first quadrant is shown. The gyro case 1 moves to the north (in the direction from B to A in FIG. 4) due to the north-south acceleration α, and the gyro case 1 is inclined. However, since the viscosity of the liquid 7 is high, the gyro case 1
Is small, and the inclination angle θ of the gyro case 1 is small. The inclination angle θ of the gyro case 1 increases in proportion to the north-south acceleration α in the conventional liquid 7, but has a small value in a liquid having a higher viscosity.

Therefore, the torque acting on the gyro case 1
Is smaller than the torque expressed by the equation (5), and the acceleration is
Error ∠n₀The value of On is smaller than in the case of FIG.
Heading φ indicated by master compass_M= ∠nOH is good
The value becomes larger. However, the master compass
Show heading φ_MSpeed error correction angle δ to correct _V
= HOP is obtained by the calculation formula of the equation (2).
6B. Therefore, the repeater compass
Show heading φ_R= ∠nOP is greater than in FIG. 6B
Value.

FIG. 7C shows a state where the ship turns further clockwise and is located in the second quadrant. Similarly, the value of the acceleration error Δn ₀ On is smaller than in the case of FIG. 6C, and the azimuth On of the master compass is still the angle ΔnO from the true north direction ON.
It is west biased by N.

The heading φ _M indicated by the master compass is 9
The sign of the speed error correction angle δ _V that is larger than 0 degrees is negative,
Heading phi _R indicated by repeater compass therefore, greater than heading phi _M indicated master compass.

FIG. 7D shows a state where the ship has turned further clockwise. Even in this state, the direction of the master compass On
Is westwardly deviated by a slight angle ΔnON from the true north direction ON, but is close to the true north direction ON. The speed error correction angle δ _V = VHOP is substantially equal to the value calculated in the case of FIG. 6D. Therefore, the heading φ _R = ∠nOP indicated by the repeater compass is close to 180 degrees. At this time, the driver switches from turning to straight traveling, but the actual heading OH is not facing south.

In this way, the ship takes a course deviated from the true south direction OS even though the ship is to go south.
The spin axis G of the gyro rotor of the master compass
S gradually rotates clockwise, and when the heading OH travels in the true south direction, it is finally located at the same rotation position as in FIG. 6D.

This is because the acceleration error δ _A does not immediately become zero even if the vehicle ends and turns south. The inclined gyro case 1 is disposed in the liquid 7 having a high viscosity, and does not immediately return to the original position even when the acceleration α becomes zero. Therefore, until the gyro case is completely returned to its original position, the torque due to the inclination is applied to the gyro case 1, the acceleration error [delta] _A is generated.

In any case, an error occurs every time the vehicle is accelerated / decelerated or turned, and the error is not deleted unless a predetermined time, several minutes to several tens minutes, has elapsed after switching to the navigation at a constant speed.

The gyro compass having the gyro ball type fingering device has been described as an example.
This is common not only to the gyroscopic finger pointing device but also to a finger pointing device that generates an acceleration error and has a relatively large time constant.

In view of the above, an object of the present invention is to eliminate acceleration and deceleration and turning errors in a gyrocompass having a finger north device that generates an acceleration error and has a relatively large time constant.

[0075]

According to the present invention, there is provided a gyro case incorporating a gyro rotor having a substantially horizontal spin axis, a support device for supporting the gyro case with three degrees of freedom, and the gyro. A fingering device for applying a torque with a time delay of a predetermined time constant in proportion to the inclination angle of the spin axis of the rotor with respect to the horizontal plane around the horizontal axis orthogonal to the spin axis with respect to the gyro case;
An azimuth transmitter for detecting the heading with respect to the spin axis, a speed error correction angle calculated from the output of the azimuth transmitter, the speed and the latitude of the vehicle, and correcting the output of the azimuth transmitter based on the speed error correction angle In the gyro compass having a speed error correction device, the speed error correction device has a first-order lag filter having a time constant substantially equal to the time constant of the finger north device, and the speed error correction angle is equal to the first-order lag filter. It is configured to correct the output of the azimuth transmitter after passing through.

According to the present invention, the time constant of the first-order lag filter is set such that the speed error correction angle is substantially equal to the angle between the spin axis and the meridian during acceleration or deceleration or turning.

Therefore, in a gyro compass having a finger northing device that generates an acceleration error and has a relatively large time constant, errors during acceleration / deceleration and turning can be completely eliminated.

[0078]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a gyro compass of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of an error correction unit of a gyro compass according to the present invention. The main body of the gyro compass may be the same as the configuration of the conventional gyro compass described with reference to FIGS. In the case of the present example, the viscosity of the liquid 7 loaded in the tank 2 of the fingering apparatus shown in FIG. 4 is higher than that of the conventional one.

The gyro compass is the master compass, and the output of the gyro compass is supplied to the repeater compass. The repeater compass indicates the output of the error correction unit.

The error correcting section of the present example comprises a speed error calculating section 36
And a time delay calculating unit 37 and a direction correcting unit 38. The speed error calculation unit 36 calculates the speed error correction angle δ _V by substituting the speed V, the latitude λ, and the azimuth C into the equation (2). The azimuth C may be the azimuth φ _M supplied from the master compass. That is, the azimuth angle C may be supplied from the azimuth transmitter 35 attached to the master compass.

Azimuth angle φ supplied from master compass
_{Since M} has not yet been corrected, it includes an error. Therefore, the speed error correction angle δ _V obtained by the equation (2) is not accurate, but the error is small and can be ignored.

The output of the speed error calculator 36 is supplied to a time delay calculator 37. The time delay calculation unit 37 is substantially a first-order delay filter, and outputs the speed error correction angle δ _V with a delay corresponding to the time constant T _P. Time constant T
_P is set to a value close to the constant T _G when ubiquitous device,
The setting method will be described later in detail.

If the output of the speed error calculator 36 is a digital signal, the time delay calculator 37 may be constituted by appropriate software. If the output of the speed error calculating section 36 is an analog signal, the time delay calculating section 37 may be constituted by a circuit including a suitable operational amplifier or an OP amplifier.

The output of the time delay calculation unit 37 is
8 to correct the azimuth angle φ _M supplied from the master compass. According to the present embodiment, the azimuth angle phi _M indicated master compass, not by the speed error correction angle [delta] _V in the same time, is corrected by the speed error correction angle [delta] _V at the time delayed by a time corresponding to a time constant T _P You.

The azimuth correcting unit 38 outputs the azimuth corrected by the velocity error correction angle δ _V as an output of the gyro compass. When the gyro compass is a master compass and the master compass is connected to the repeater compass, the output of the azimuth correction unit 38 is supplied to the repeater compass 40, and the repeater compass 40 removes the error from the azimuth δ. Indicate _R.

The azimuth correction unit 38 has a signal conversion function as well as an error correction calculation function. For example, it converts the velocity error correction angle δ _V output from the time delay calculation unit 37 into a signal that can be added to the output of the azimuth transmitter 35 of the master compass. Further, when the repeater compass 40 is configured to instruct the azimuth [delta] _R by rotating the card in step motors, the azimuth correcting unit 38
Are configured to have the function of a converter that outputs a step signal.

Referring to FIG. 2, the function of the error correction device according to the present invention will be described. FIG. 2A shows the azimuth of the ship traveling northward at a constant speed and the master compass, that is, the spin axis GS of the gyro rotor. 6A and 7A,
Detailed description is omitted.

FIG. 2B shows that the ship starts turning clockwise and the heading OH is in the first quadrant of the plane coordinates. The magnitude of the acceleration error δ _A = ∠n ₀ On is the same as in FIG. 7B. Therefore, the heading φ _M indicated by the master compass
= ∠nOH is also the same as in FIG. 7B. However, the speed error correction angle δ _V = ∠POH is larger than in FIG. 7B. This is because the speed error correction angle δ _V calculated by the speed error calculation unit 36 in FIG. 1 is output via the time delay calculation unit 37, and thus becomes a value close to the value before turning. Therefore, the magnitude of the heading φ _R = ∠nOP indicated by the repeater compass 40 is smaller than the case of FIG. 7B.

FIG. 2C shows that the ship turns further and the heading OH
Indicates a state in the second quadrant. Acceleration error δ_A= ∠n₀
The magnitude of On is the same as in FIG. 7C. Therefore trout
Heading φ indicated by tur compass_M= ∠nOH size
This is the same as the case of FIG. 7C. However, speed error correction
Regular angle δ_VIs different from the case of FIG. 7C. In the case of FIG.
Degree error correction angle δ_VIs negative, but the field of FIG.
Speed error correction angle δ _VIs still positive. Follow
And the heading φ indicated by the repeater compass 40_R= ∠nO
P is the heading φ indicated by the master compass_M= ∠nOH
Smaller than that of FIG. 7C.

FIG. 2D shows a state in which the ship turns further and the heading φ _R = ∠nOP indicated by the repeater compass 40 approaches 180 degrees. The sign of the velocity error correction angle δ _V is still positive, and the heading φ _R = ∠ indicated by the repeater compass 40 is
nOP is the heading φ _M = ∠nO indicated by the master compass
Smaller than H. At this time, if there is the following relationship, the actual heading OH of the ship is pointing to the true south direction OS.

[0091]

１１nON = ∠POH

[0092] It is to azimuth ∠nON gyro spin axis GS is equal to the speed error correction angle [delta] _V.

FIG. 2D shows a state in which the ship has finished turning and traveling south at a constant speed. At this point, the north-south acceleration α acting on the gyro case 1 is zero,
The gyro case 1 has not returned to the center position of the tank 2 yet. Therefore, there is a torque due to the inclination of the gyro case 1, and the magnitude of the acceleration error δ _A = ∠n ₀ On increases. However, the speed error correction angle δ _V changes from positive to negative, and the heading φ _R indicated by the repeater compass 40
= ∠nOP is the heading φ _M indicated by the master compass.
It becomes larger than nOH. Eventually, the state becomes the same as the state of FIG. 6D. Heading φ _R indicated by repeater compass 40 =
∠nOP is 180 degrees.

[0094] described a method for setting the constant T _P when the filter. Constant T _P when filters are over before and after the turning of the vessel and turning, as the numerical formula 11 is satisfied, are selected. In the case of FIG. 6, the relationship of Expression 11 does not hold, but in the case of this example, Expression 11 holds during and before and after the turning of the boat. Filter time constant T _P
Is set to a value equal to or close to the time constant _TG of the north-south movement of the gyro case 1, for example.

As described above, the acceleration error δ _A is caused by the inclination of the gyro case 1. Therefore, the acceleration error δ _A
Is caused by the north-south acceleration α acting on the gyro case while the ship is turning, but the gyro case 1 can be operated even when the turning is completed and the north-south acceleration α becomes zero.
Exist until it returns to the center position of the tank 2. However, in the case of the presence of the north-south direction of the acceleration alpha, in case the acceleration alpha north-south direction is zero, strictly speaking, different equations of motion for pre-session, the change in acceleration error [delta] _A is different.

On the other hand, the speed error correction angle δ_Vby
The correction is a continuous operation, and the two do not match. However
According to the research of the inventor of the present invention, the time
Number T _PIs the time constant T of the north-south motion of gyro case 1.
_GBy setting it equal to or close to
To correct the azimuth angle of the gyro spin axis GS
Angle δ_VCan be substantially equal to

In the above, the case where the present invention is applied to a gyro compass having a gyro-ball type finger north device has been described. However, the present invention is applicable to a gyro compass having a finger north device causing a similar acceleration error. .

At present, the world's first unshooted gyrocompass and 191 that were successfully commercialized in 1908
Four to five types of gyrocompasses have been put into practical use, in addition to the Sperry gyrocompass that was successfully commercialized for the first time in one year. However, all gyrocompasses for civil use are configured to be used in a speed range of 30 knots or less, and a gyrocompass usable for a high-speed ship of 70 knot class has not yet been realized.

According to the present invention, a gyrocompass which can be used for a high speed ship of a 70 knot class can be realized, which will be good news for sailors in the world.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described examples, and it is understood by those skilled in the art that various changes, modifications, and substitutions can be made within the scope of the present invention. It would be obvious.

[0101]

According to the present invention, there is an advantage that a gyro compass that can be used for a high-speed ship of a 70 knot class can be provided.

According to the present invention, a simple device can be added to the conventionally used gyro compass, and
There is an advantage that a gyro compass that can be used for a 0 knot class high-speed ship can be provided.

According to the present invention, the time constant of the first-order lag element is increased and the arithmetic unit including the first-order lag filter corresponding thereto is added to the gyrocompass provided with the finger device having the first-order lag element. There is an advantage that it is possible to provide a gyro compass that can be used for high-speed ships of 70 knot class.

[Brief description of the drawings]

FIG. 1 is a block diagram of an error correction unit of a gyro compass according to the present invention.

FIG. 2 is an explanatory diagram illustrating a gyro compass error correction method according to the present invention.

FIG. 3 is a diagram showing a configuration of a conventional gyrocompass.

FIG. 4 is a view showing a configuration of a conventional fingering device of a gyrocompass.

FIG. 5 is an explanatory diagram for explaining a ballistic error when a ship turns.

FIG. 6 is an explanatory diagram for explaining a conventional gyro compass error correction method.

FIG. 7 is an explanatory diagram for explaining a principle of generating a gyrocompass error in a high-speed ship.

[Explanation of symbols]

1 gyro case (gyro ball), 2 tank,
3 Suspension line, 4N, 4S Primary coil, 5N, 5S
Secondary coil, 6 non-contact displacement detector, 7 liquid,
8, 8 'horizontal axis, 9 horizontal gear, 10 horizontal servo motor, 11 horizontal pinion, 12 horizontal ring,
13, 13 'horizontal bearing, 14, 14' gimbal shaft, 15, 15 'gimbal bearing, 16 vertical ring, 17, 17' vertical shaft, 19 direction servo motor, 20 direction pinion, 21 direction gear, 22
Compass card, 23 boards, 24 board instruments, 25,
25 'vertical bearing, 26 baseline, 35 direction transmitter, 36 speed error calculator, 37 time delay calculator, 38 direction corrector, 40 repeater compass

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Michio Fukano 2-16-46 Minami Kamata, Ota-ku, Tokyo Inside Tokimec Co., Ltd.

Claims (2)

[Claims] A gyro case having a built-in gyro rotor having a substantially horizontal spin axis;
A supporting device for supporting the shaft with a degree of freedom; a horizontal axis perpendicular to the spin axis with respect to the gyro case; A finger pointing device for applying around the axis, a heading detector for detecting the heading with respect to the spin axis, a speed error correction angle calculated from the output of the heading transmitter, the speed and the latitude of the navigation body, A gyro compass having a speed error correction device that corrects the output of the bearing transmitter according to an error correction angle, wherein the speed error correction device has a first-order lag filter having a time constant substantially equal to the time constant of the finger north device. A gyro-conversion device, wherein the speed error correction angle is configured to correct the output of the azimuth transmitter after passing through the first-order lag filter. path. 2. The gyro according to claim 1, wherein the time constant of the first-order lag filter is set such that the speed error correction angle is substantially equal to the angle between the spin axis and the meridian during acceleration or deceleration or turning. compass.