JPS59163508A - North directing and statically determining method of gyrocompass for vessel, and its control device - Google Patents

Abstract

PURPOSE:To shorten the time required before a gyro spin shaft direct to the north and is statically determined after a gyro is started, and to avoid an unnecessary operation when a vessel is at anchor by increasing the gain of a differential operating part and shortening a period of a precession of the gyro spin shaft, before sailing of a vessel, and decreasing the gain and setting it to a period of a necessary precession at the time of navigation. CONSTITUTION:A gyro 12 is rotated. When a gyro spin shaft 5 is inclined from a horizontal surface 9 of the earth in a state that the gyro 12 is rotated at a high speed, its inclined angle beta is detected as an electrical signal by an inclined angle detector 6. This inclined angle signal is feeble, therefore, it is amplified, and proportional and differential operations are executed by a proportional and differential operating part 18, and its output is inputted to a torque motor 8. A torque being proportional to inputted voltage is applied to a vertical frame 3, and the gyro spin shaft 5 executes a precession. As for this precession, a torque of the same phase and a control torque which leads by a phase angle of 90 deg. are applied, therefore, it is attenuated gradually without executing a sustained oscillation-like motion, and the gyro spin shaft 5 is directed to the due north and statically determined.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for determining north direction for a marine gyro compass and a control device therefor. The present invention relates to a method for determining north direction of a marine gyro compass and a control device thereof.

The high-speed rotating gyro of the gyro compass has the property of continuing to point in the same direction in absolute space, regardless of the rotation of the earth, unless it receives an external force. Furthermore, when a force is applied to the gyro from the outside, it has the property of rotating in the direction perpendicular to the force (hereinafter referred to as precession). Therefore, the gyro compass makes use of these two properties to enable the pointing of the gyro spin axis to the north.

- In conventional marine gyro compasses, the center of gravity of the entire vertical frame including the gyro case that rotates at high speed is located below the horizontal axis for supporting the freely rotatable vertical frame. Therefore, if the gyro spin axis is tilted vertically from the horizontal plane of the earth due to the rotation of the earth, the precession of the gyro spin axis will be the gyro spin axis caused by the gravitational action due to the tilt of the entire vertical frame. This is done by direct torque about the vertical frame supporting horizontal axis perpendicular to . Further, the damping action for statically fixing the gyro spin axis to the true north can be achieved by applying a torque proportional to the tilt angle around the vertical axis of the gyro case using a tamping weight, or
The inclination of the vertical frame support horizontal axis in the distributed oil bath is achieved by applying torques of \90 different degrees, each relying on a mechanical direct torque associated with the inclination angle.

However, in a gyro compass with such a configuration, the period of precession of the gyro spin axis is fixed, so if you want to change the period, you need to change the rotation speed of the gyro.

On the other hand, in the gyro compass 1 as shown in FIG. 1, the center of gravity of the entire vertical frame 3 including the gyro case 2 is located at a position that coincides with the rotatable vertical frame supporting horizontal axis 4, so the gyro pin Even if the shaft 5 is tilted at an angle β from the horizontal plane 9 of the earth, the gravitational effect due to the tilt of the entire vertical frame 3 does not work, and around 1 the tilt angle detector 6, the electronic control device 7, and the torque motor 8 driven thereby As a result, torque is generated around the horizontal shaft 4 for supporting the vertical frame, and the gyro spin shaft 5 is statically fixed to the true north N.

However, in such a marine gyro compass, in order to reduce the pointing error of the gyro spin axis that occurs when the ship changes course or speed, conventionally, the precession period of the gyro spin axis or the inherent 1 The theoretical value is 84.4 minutes, but 1JTi usually
A value between 70 and 90 minutes is adopted. therefore,
The above-mentioned natural period is also applied before the ship departs, that is, when the ship is anchored at a port or the like, from the time the gyro is started until the gyro spin axis is fixed to the north. As a result, it takes a long time of 3 to 4 hours to determine the north direction, and the time required for the ship to prepare for departure and the time it takes to set sail may become longer (or, in order to avoid this, the gyro must be operated even while at anchor). There are drawbacks that must be avoided.

The present invention was made in order to solve the above-mentioned problems, and it shortens the time from starting the gyro until the gyro spin axis is fixed to the north, thereby shortening the time required from preparation for sailing to sailing. It is an object of the present invention to provide a method for determining the north direction of a gyro compass for a ship, and a control device thereof, which can avoid unnecessary operation while at anchor.

Its characteristic is that when the center of gravity of the entire vertical frame including the gyro case is placed at the same position as the horizontal axis for supporting the vertical frame, which can freely rotate, the gyro spin axis moves around the earth due to the earth's rotation. The inclination angle with respect to the horizontal plane is electrically detected by the inclination angle detector attached to the vertical frame, the output signal is calculated by the proportional/differential calculation section, and the output drives the torque motor attached to the horizontal frame. In a marine gyro compass, the gyro spin axis is pointed by applying 1-lux to the vertical frame, and the movement of the gyro spin axis is servo-tracked by the tracking frame to avoid twisting the suspension line. In order to fix the gyro spin axis to the north in a short time, the key of the proportional/differential calculation section is increased to shorten the period of precession of the gyro spin axis. In order to reduce the fluctuation in the index of the gyro spin axis, a method for determining the north direction of a marine gyro compass has been developed in which the gain is reduced to provide the necessary precession period. In order to carry out the method, a control circuit for ships is equipped with a gain setting section that outputs two different types of gains to the proportional/derivative calculation section, and a gain switching section that selects one of the two types of gains. This is a gyro compass pointing north static control device.

Hereinafter, the present invention will be explained in detail based on examples thereof.

FIG. 2 is a sequence block diagram for stably fixing the gyro spin axis to true north, which will be described without reference to each component of the gyro compass 1 shown in FIG. 1. Figure 2 shows a circuit 10 that converges the precession of the gyro spin axis 5 by using the inclination angle β with the horizontal plane 8 of the earth due to the earth's rotation, and a suspension line 13 that suspends the gyro case 2 so that it does not twist. The circuit 11 drives the follow-up frame 24 based on the declination angle between the gyro case 2 and the vertical frame 3. 12 is a gyro that rotates at high speed, and is located at the upper part 3a of the vertical frame 3.
The gyro case 2 is housed in a gyro case 2 which has a vertical shaft 14 supported by an IU suspension wire 13 and rotatably supported by the upper and lower parts 3b and 3C of the vertical frame 3. 6 of the circuit 10 is an inclination angle detector which electrically detects the inclination angle β between the gyro spin axis 5 and the horizontal plane 9 of the earth due to the rotation of the earth from the gyro 12, and is mounted on the vertical frame 3. Reference numeral 15 designates a cane setting unit that outputs two different types of canes to a proportional/differential calculation unit 18 in a control circuit 16, which will be described next, provided in the electronic control device 7. a cane switch for selecting one of the seed gains;
18 performs proportional and differential calculations based on the selected gain,
This is a proportional/differential calculation unit that outputs a drive control signal for the torque motor 8, which will be described later. Note that the cane switching unit 17 is switched when starting the gyro while the ship is at anchor and when leaving the ship.When I] in the figure is connected, a large gain is selected, and when L is connected, the gain is selected. A small gain is selected. Reference numeral 8 denotes a torque motor mounted on the horizontal frame 19, which is an AC or DC motor driven by a signal calculated based on the tilt angle β electrically detected by the tilt angle detector 6. .

On the other hand, 20 of the circuit 11 is the vertical frame 3 of the gyro spin shaft 5.
This is a follow-up sensor that detects the declination angle of the gyro spin axis 5, and is mounted inside the vertical frame 3 facing a reference plane 2a parallel to the gyro spin axis 5 provided outside the gyro case 2. This is to detect the declination angle of the gyro case 2 with respect to the vertical frame 3. 21 is a servo motor 2 based on the declination detected by the tracking sensor 20.
2 is a servo motor controller provided in the electronic control device 7 that outputs a drive signal, and 23 is a follower gear that decelerates the movement of the servo motor 22 and transmits the same to the follower frame 24. In addition, 25 is an azimuth scale board fixedly installed on the upper surface of the follower frame 24, and the vertical frame 3 is connected to the horizontal direction outside the vertical frame 3 via a vertical frame supporting horizontal shaft 4 that is orthogonal to the vertical axis 14. The horizontal frame 19 is supported by a frame 19, and the horizontal frame 19 is supported by a follower frame 24 on the outside of the horizontal frame 19 via a horizontal frame support horizontal shaft 26 which is perpendicular to the vertical frame support horizontal shaft 4.

Therefore, the vertical frame 3 is also rotated by the motor 22 to track the gyro spin axis 5.

Since the present invention has been constructed as described above, the operation sequence for determining the pointing north position of the gyro compass 1 will be explained next.

First, the operation of stabilizing the gyro spin shaft 5 to the north before the ship departs will be explained. First, rotate the gyro 12. When the gyro spin axis 5 is tilted from the horizontal plane 9 of the earth while the gyro 12 is rotating at high speed, the tilt angle β is detected as an electric signal by the tilt angle detector 6 mounted on the vertical frame 3. This tilt angle signal is weak, so
This is amplified and proportional and differential calculations are performed by the proportional/differential calculation section 18, and the output thereof is input to the torque motor 8. A torque proportional to the voltage input to the torque motor 8 is applied to the vertical frame 3, causing the gyro spin shaft 5 to precess. The direction of this movement depends on whether the tilt angle signal is positive or negative.
That is, the gyro spin axis 5 is /
It differs depending on the direction of the output torque, which is determined by whether it forms an rl'l angle or an depression angle. This precession is affected by the in-phase torque proportional to the inclination angle and the so-called braking torque, which is 90 degrees ahead of the phase, so it gradually attenuates without a sustained oscillatory motion, and after a certain period of time, the gyro The spin axis 5 is statically fixed facing due north.

The state of this damping can be easily understood because it can be expressed by linear approximation of the equation of motion of a commonly used gyro, and is expressed in the form of a damped vibration differential equation of a quadratic system.

Now, let α be the declination angle from the true north of the gyro spin axis 5, β be the inclination angle from the horizontal plane, and linearly approximate the declination angle α and the J'J oblique angle β as infinitesimal angles, then the gyro spin axis 5 The motion with respect to the direction of is H((dα/dt) −t
−ωasinLl =T---11) The motion related to the tilt of the gyro spin axis 5 is H(ωα*cosl−+(d
β/dt) = 0 (2) The relationship between the inclination angle β and the output torque 'F of the torque motor 8 is T=B (β
+Td(dβ/at) l −(3).

In addition, in formulas (1) to (3), H is gyro 12
, ω is the angular velocity of the earth's rotation, L is the latitude, T is the output I-lux of the torque motor 8, and Td is the
The differential time constant of the differential circuit, B, is a constant, which is Cain, which indicates the ratio of the output torque to the unit inclination angle of the torque motor 8.

From the above equations (1) to (3), the declination α of the gyro spin axis 5 from the due north is summarized as follows: H((d'α/dt2) +BTdω・(dα/dt)
, cos L+ B ωα association cos L = O---(
41, and the damping curve can be found by giving the initial conditions.

Therefore, even if the gyro spin axis 5 deviates from true north, it gradually approaches true north and eventually converges to true north, that is, the declination angle α is zero. Note that, as is clear from equation (4), since there is no constant term, the gyro compass using the control described later has the characteristic that no error in latitude occurs.

This attenuating state is shown in a block diagram as shown in FIG. By the way, dβ/dt in the figure is dβ/dt--ω・cos L・α obtained from equation (2),
dα/dt is obtained from equations (1) to (3).
dt-βB/H-ω-5rnL-BTdω・cosL・
α/H. α1 and β1 in the figure are initial conditions of α and β, respectively.

In the above equation (4), the natural frequency ω0 of undamped vibration
is, ω0-j stone 3 er>-cosL) The natural period To is To=2π West [1 penalty;=100 The damping coefficient ζ of the damped vibration is ζ − (Td/2); The damping period Ta is Ta = To/W〒]716-, and the torque cane B of the torque motor and the differential time Td
If we take an appropriate value, the natural period TO and the damping coefficient ζ
can be selected arbitrarily.

Therefore, if the above-mentioned gain B is made large, the natural period To becomes small, so the time from the activation of the gyro until the gyro spin axis 5 is statically fixed to the true north becomes shorter.On the other hand, if the gain B is made small, , the natural period To becomes larger, so it is possible to lengthen the time it takes to settle to true north.

In order to facilitate understanding, the explanation will be made with reference to a block diagram shown in FIG. 3 in which the gyro spin axis 5 is statically fixed to the true north.

When contact I] is artificially selected by the gain switching section 17 shown in FIG.

When the tilt angle detector 6 detects the tilt angle β in this state, a torque is applied to the vertical frame 3 as described above, and the motion of the gyro spin axis 5 with respect to the deflection angle α continues as shown by the line M in FIG. This results in a rapidly damped motion as shown by line N, which oscillates. On the other hand, the declination angle of the gyro spin axis 5 that occurs at this time, that is, the declination angle between the gyro case 2 and the vertical frame 3, is detected by the follow-up sensor 20, and after being calculated by the servo motor controller 21, the servo motor controller 21 drives the serhomoke 22. The follower frame 24 is rotated via the follower carrier 23 to prevent the suspension line 13 from being twisted by the movement of the gyro spin shaft 5.

Next, as mentioned above, while the ship is sailing, in order to reduce the pointing error of the gyro spin axis 5 that occurs when changing direction or speed, the period of precession of the gyro spin axis 5 that has been conventionally adopted is as follows. When the contact is selected in the cane switching unit 17 just before departure so that the value of 70 to 90 minutes is obtained, the smaller of the two types of gains output from the gain setting unit 15 is set to the proportional/differential calculation unit 18. is input.

The subsequent operations and calculations are no different from those at the time of startup described above. As a result, the motion of the gyro spin axis 5 with respect to the deflection angle α becomes a sustained oscillation as indicated by line I) in FIG. 4, and a slow-damped motion as indicated by line Q.

As can be seen from the above explanation, by switching the gain, it is possible to avoid errors in changing the direction or speed of the gyro compass when the ship is sailing, and to shorten the time from startup to fixing the designated north. .

As explained in detail above, the present invention increases the gain of the proportional/differential calculation section to fix the gyro spin axis to the north in a short time before the ship departs. By shortening the period of differential motion, during navigation,
In order to reduce the fluctuation of the finger speed of the gyro spin axis,
Since we have created a marine gyro compass that reduces the gain to achieve the necessary precession period, the time from starting the gyro until the gyro spin axis is fixed to the north is shortened, making it easier to prepare for sailing. The time required for departure can be shortened. Therefore, it is possible to facilitate the start-up of a ship, especially the departure of a small ship, and to avoid unnecessary power consumption by eliminating the need for operation while at anchor. Moreover, since it generates the necessary north static fixing torque electrically, the entire device can be made smaller and lighter than a gyro compass that generates torque purely mechanically, which in turn allows for smaller installation space. There is.

[Brief explanation of drawings]

Figure 1 is a perspective view of the electric gyro compass, Figure 2 is a sequence block diagram for determining north direction, Figure 3 is a block diagram showing the state of attenuation of the gyro spin axis, and Figure 4 is the gyro spin axis. is an oscillation diagram of the precession of 1-gyro compass, 2-gyro case, 3-vertical frame, 3a-upper part, 3b, 3C-upper and lower parts, 4-horizontal axis for vertical frame support, 5-gyro spin axis, 6-tilt angle detector,
8-1~lux motor, 9-horizontal plane, 12-gyro, 1
3-suspension line, 14-vertical axis, 15-gain setting section, 16
-Control circuit, 17-Gain switching section, 18=-Proportional/differential calculation section, 19-Horizontal frame, 24-Following frame, 26-Water shaft for supporting horizontal frame, β-Inclination angle Patent applicant Kawasaki Heavy Industries, Ltd.

Claims (2)

[Claims] (1) A gyro case housing a gyro that rotates at high speed is supported by a suspension line from the top of a vertical frame, and is supported at the top and bottom of the vertical frame so that the vertical axis of the gyro case can rotate freely, and , the vertical frame is supported by a horizontal frame outside the vertical frame via a vertical frame supporting horizontal axis perpendicular to the vertical axis, and further, the horizontal frame is perpendicular to the vertical frame supporting horizontal axis. It is supported by a follower frame outside this horizontal frame via a horizontal frame support horizontal shaft,
The inclination angle that the gyro spin axis makes with the horizontal plane of the earth due to the rotation of the earth when the center of gravity of the entire vertical frame including the gyro case is placed in the same position as the rotatable horizontal axis for supporting the vertical frame. is electrically detected by a tilt angle detector attached to the vertical frame, the output signal is calculated by a proportional/differential calculation section, and the output is used to drive a torque motor attached to the horizontal frame. , in a marine gyro compass in which a torque is applied to the vertical frame to point the gyro spin axis, and a movement of the gyro spin axis is servo-tracked by a tracking frame so that the suspension line is not twisted; In order to fix the gyro spin axis to the north in a short time, the gain of the proportional/differential calculation section is increased to shorten the period of precession of the gyro spin axis (and also to reduce the period of precession of the gyro spin axis). In order to reduce the fluctuation of the index of the gyro spin axis, the gain is made smaller to obtain a period of precession necessary for the precession period. (2) A gyro case housing a gyro that rotates at high speed is supported by a suspension line from the top of the vertical frame, and the vertical axis of the gyro case is rotatably supported at the top and bottom of the vertical frame, and , the vertical frame is supported by a horizontal frame outside the vertical frame via a vertical frame supporting horizontal axis perpendicular to the vertical axis; The outer follower frame of this horizontal frame is supported via a horizontal shaft for supporting the horizontal frame,
The inclination angle that the gyro spin axis makes with the horizontal plane of the earth due to the rotation of the earth when the center of gravity of the entire vertical frame including the gyro case is placed in the same position as the rotatable horizontal axis for supporting the vertical frame. is electrically detected by a bevel detector mounted on the vertical frame, its output signal is calculated by a proportional differential calculation section, and the output drives the torque motor mounted on the horizontal frame. Because of this, 1) j1
A torque is applied to the vertical frame to point the gyro spin axis north, and the movement of the gyro spin axis is tracked by the tracking frame so as not to twist the suspension line. A guide to a marine gyro compass, characterized in that it is equipped with a control circuit having a gain setting section that outputs two different types of gains to the section, and a gain switching section that selects one of the two types of gains. Static control device.