Gyrocompass

Abstract

To provide a technique capable of inexpensively shortening a settling time until becoming an operable state as a gyrocompass.SOLUTION: A gyro case having a gyro rotor built therein, a tank accommodating the gyro case therein, and degrees of freedom of three axes including a first axis oriented in a spin axis direction of the gyro rotor, a second axis orthogonal to the first axis and parallel to a horizontal plane, and a third axis orthogonal to the first axis and the second axis, and a horizontal tracking system that causes the tank to track around the second axis so as to maintain a relative posture of the tank with respect to the gyro case based on a displacement amount that is a displacement of the posture of the gyro case around the second axis detected by the detection unit, the horizontal tracking system including a horizontal movement amount calculation unit that controls a movement detection amount that is a movement amount of the tank detected by the detection unit to a movement target amount.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a gyrocompass. [Background technology]

[0002] Gyrocompasses have traditionally been used as a means for determining accurate direction. These gyrocompasses have a north-guiding function, where the direction of the rotation axis of the gyro always points north-south, in addition to the direction retention function, where the direction of the rotation axis of the gyro always maintains a fixed direction in space, i.e., one end of the rotation axis always points north.

[0003] Furthermore, because gyrocompasses are mounted on moving vehicles such as ships, high accuracy is required in both static and dynamic aspects. Static accuracy is affected by the ratio between the angular momentum of the gyro housed in the gyro case and harmful torque, such as friction, applied to the gyro case. Therefore, in order to improve static accuracy without increasing angular momentum, known technologies include gyro cases that are not supported by ball bearings or the like but are supported by methods that apply less friction, and technologies that detect deviations of the gyro case without contact.

[0004] One known example of such a gyrocompass is a gyro device that includes a gyro case with a built-in gyro, a tank that houses the gyro case together with a liquid, a first support device that supports the gyro case in the tank by connecting the tank and gyro case with a suspension body, a second support device that supports the gyro case so that it has three degrees of freedom, and a vertical follow-up device that causes the tank to follow the gyro case around the line of gravity (see Patent Document 1). Here, the three axes of the second support device are the spin axis of the gyro, a vertical axis that is perpendicular to the spin axis and faces vertically, and a horizontal axis that is perpendicular to the spin axis and the vertical axis and faces in the east-west direction.

[0005] Generally, the gyro device used in a gyrocompass has an orientation tracking system and a horizontal tracking system that cause the tank to follow the gyro case around the vertical axis and the horizontal axis, and is configured to calculate and output an orientation signal based on the displacement of the gyro case detected by these orientation tracking system and horizontal tracking system.

[0006] Also known as technology related to such gyro devices is a gyro device equipped with a horizontal tracking system that corrects the amount of rotational displacement of the gyro case relative to the tank around the horizontal axis and maintains the tank's relative attitude with respect to the gyro case based on the corrected amount of rotational displacement (see Patent Document 2).Also known is a gyro device that starts operating as a compass with the north end of the gyro compass pointing due north (see Patent Document 3). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 0885730 specification [Patent Document 2] Patent No. 6985906 specification [Patent Document 3] Patent No. 3467633 specification Summary of the Invention [Problem to be solved by the invention]

[0008] The problem to be solved by the embodiments of the present invention is to provide a technology that can reduce the settling time required for a gyrocompass to become operable at low cost. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the gyrocompass of this embodiment includes a gyro case that incorporates a gyro rotor, a tank that houses the gyro case, a support unit that supports the tank and has degrees of freedom about three axes, including a first axis that faces the spin axis direction of the gyro rotor, a second axis that is perpendicular to the first axis and parallel to a horizontal plane, and a third axis that is perpendicular to the first axis and the second axis, a detection unit that detects displacement of the attitude and position of the gyro case relative to the tank in a non-contact manner, and a horizontal tracking system that causes the tank to follow the tank around the second axis so as to maintain the attitude of the tank relative to the gyro case based on the displacement amount that is the displacement of the attitude of the gyro case about the second axis detected by the detection unit, and has a horizontal movement amount calculation unit that controls the movement detection amount, which is the movement amount of the tank detected by the detection unit, to a movement target amount. [Effects of the Invention]

[0010] According to an embodiment of the present invention, the settling time required for the gyrocompass to become operable can be reduced at low cost. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic perspective view showing a gyrocompass according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the configuration of a detection unit according to the first embodiment. [Figure 3] FIG. 2 is a schematic diagram showing the configuration of an azimuth tracking system according to the first embodiment. [Figure 4] FIG. 2 is a schematic diagram showing the configuration of a horizontal tracking system according to the first embodiment. [Figure 5] 2 is a schematic diagram showing the north-pointing action of the gyro rotor according to the first embodiment. FIG. [Figure 6] FIG. 1 is a schematic diagram showing the configuration of a vibration damping system according to a first embodiment. [Figure 7] FIG. 2 is a block diagram showing the configuration of a control unit according to the first embodiment. [Figure 8]FIG. 2 is a schematic diagram showing a gyro case inside the tank when an offset θoff is applied according to the first embodiment. [Figure 9] FIG. 2 is a control block diagram showing the configuration of a horizontal deviation signal processing unit according to the first embodiment using a Laplace operator. [Figure 10] 10 is a flowchart showing the operation of a horizontal movement amount control process according to the first embodiment. [Figure 11] FIG. 10 is a block diagram showing the configuration of a control unit according to a second embodiment. [Figure 12] FIG. 10 is a control block diagram showing the configuration of a horizontal deviation signal processing unit according to a second embodiment using a Laplace operator. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] First Embodiment (Gyrocompass configuration) The configuration of a gyrocompass according to a first embodiment will be described. Fig. 1 is a schematic perspective view showing a gyrocompass according to this embodiment. For the sake of explanation, Fig. 1 shows a state in which a tank and a panel are partially cut away. In this embodiment, a gyrocompass mounted on a ship as a navigation body is shown.

[0014] As shown in FIG. 1, the gyrocompass according to this embodiment includes a gyro case 1, a tank 2, a horizontal ring 12, a vertical ring 16, a roughly cylindrical panel 24 defining an internal space, and a control unit 33 (not shown in FIG. 1, see FIG. 7) that controls the gyrocompass. The gyro case 1, the tank 2, the horizontal ring 12, and the vertical ring 16 are housed in the internal space of the panel 24. The horizontal ring 12 is formed in an annular shape and is disposed so as to surround the tank 2 in the horizontal direction. The vertical ring 16 is formed in an annular shape and is disposed so as to surround the tank 2 in the vertical direction.

[0015] Gyro case 1 is formed in a liquid-tight sphere that defines an internal space, and gyro rotor G is housed within the internal space of gyro case 1. Tank 2 is a container that houses gyro case 1, and gyro case 1 is supported by being suspended within tank 2 by catenary wire 3. The upper end of catenary wire 3 is connected to tank 2, and the lower end is connected to gyro case 1. The internal space of tank 2 is filled with a highly viscous liquid 7, such as damping oil. The spin axis of gyro rotor G is configured to face the north-south direction. Detectors 6A and 6B are attached to gyro case 1 and tank 2, respectively, for contactlessly detecting displacement of the relative position and attitude of gyro case 1 with respect to tank 2.

[0016] Horizontal shafts 8A and 8B are connected to two opposing points on the equator of the tank 2 that intersect with a line perpendicular to the spin axis of the gyro rotor G, and the axes of the horizontal shafts 8A and 8B are oriented in the east-west direction, i.e., in a direction perpendicular to the spin axis and the vertical direction. The horizontal shafts 8A and 8B are each journaled by horizontal bearings 13A and 13B that are provided at two opposing points on a horizontal ring 12. A horizontal servo motor 10 that rotates a horizontal pinion 11 is attached to the horizontal ring 12, and a horizontal gear 9 that meshes with the horizontal pinion 11 is provided on the horizontal shaft 8A.

[0017] Gimbal shafts 14A and 14B are connected to two opposing points on horizontal ring 12 that intersect a line perpendicular to the axes of horizontal shafts 8A and 8B. The axes of gimbal shafts 14A and 14B are oriented in the direction of the spin axis, and gimbal shafts 14A and 14B are supported by gimbal bearings 15A and 15B that are provided at two opposing points on vertical ring 16.

[0018] Vertical shafts 17A and 17B are connected to the vertical ring 16 at two opposing locations that intersect a line perpendicular to the axes of the gimbal shafts 14A and 14B. The axes of the vertical shafts 17A and 17B are oriented vertically, and the vertical shafts 17A and 17B are supported by vertical bearings 25A and 25B, which are provided at two opposing locations in the up-down direction. The vertical bearings 25B are provided on the top surface of the disc unit 24. The vertical bearing 25A is provided on the vertical shaft 17A, which is fixed to the top surface of the azimuth gear 21 or the bottom surface of the disc unit 24. Note that FIG. 1 shows the vertical bearing 25A provided on the top surface of the azimuth gear 21.

[0019] An azimuth servomotor 19 for rotating an azimuth pinion 20 is attached to the bottom surface of the panel 24, and an azimuth gear 21 meshing with the azimuth pinion 20 is provided on the vertical shaft 17A.

[0020] A compass card 22, which is connected to the vertical shaft 17B so as to be rotatable integrally with the panel 24, is provided on the upper surface of the panel 24 so as to be rotatable relative to the panel 24. Also, a board 23, on which a baseline 26 indicating the bow direction of the ship on which the gyrocompass according to this embodiment is mounted, is provided in correspondence with the compass card 22. The gyrocompass is installed on the ship so that the baseline 26 faces the bow direction.

[0021] The gyrocompass is configured so that the tank 2 is supported with degrees of freedom about three axes: horizontal axes 8A and 8B, gimbal axes 14A and 14B, and vertical axes 17A and 17B. A portion of the detectors 6A and 6B and the azimuth servo motor 19 constitute an azimuth tracking system (described later), and the azimuth servo motor 19 is driven to maintain the positional relationship between the gyro case 1 and the tank 2 around the axis of the vertical axes 17A and 17B (hereinafter referred to as around the vertical axis). In addition, a portion of the detectors 6A and 6B and the horizontal servo motor 10 constitute a horizontal tracking system (described later), and the horizontal servo motor 10 is driven to maintain the positional relationship between the gyro case 1 and the tank 2 around the axis of the horizontal axes 8A and 8B (hereinafter referred to as around the horizontal axis).

[0022] (Configuration of the detection unit) The configuration and detection operation of the detection unit according to the first embodiment will be described. Fig. 2 is a schematic diagram showing the configuration of the detection unit according to this embodiment. Since the two detection units have the same configuration, Fig. 2 shows the north side detection unit 6A as a representative.

[0023] As shown in FIG. 2, the detection unit 6A includes a primary coil 4N, a secondary coil 5N, and a vibration-damping coil 40N. The primary coil 4N is provided on the outer surface of the gyro case 1, north of the axis of the spin axis. The secondary coil 5N is provided on the inner surface of the tank 2, corresponding to the primary coil 4N. The vibration-damping coil 40N is provided on the inner surface of the tank 2, similar to the secondary coil 5N. As described above, although not shown in FIG. 2, the detection unit 6B includes a primary coil 4S, a secondary coil 5S, and a vibration-damping coil 40S. The primary coil 4S is provided on the outer surface of the gyro case 1, south of the axis of the spin axis. The secondary coil 5S is provided on the inner surface of the tank 2, corresponding to the primary coil 4S. The vibration-damping coil 40S is provided on the inner surface of the tank 2, similar to the secondary coil 5S.

[0024] The secondary coil 5N has four rectangular coils 5NW, 5NE, 5NU, and 5NL, and similarly, the secondary coil 5S has four rectangular coils 5SW, 5SE, 5SU, and 5SL. Here, the rectangular coils 5NW and 5NE are arranged side by side in the east-west direction, and the rectangular coils 5NU and 5NL are arranged side by side in the vertical direction. Similarly, the rectangular coils 5SW and 5SE are arranged side by side in the east-west direction, and the rectangular coils 5SU and 5SL are arranged side by side in the vertical direction. Furthermore, the rectangular coils 5NW and 5NE are differentially connected to each other, and the rectangular coils 5NU and 5NL are differentially connected to each other. Similarly, the rectangular coils 5SW and 5SE are differentially connected to each other, and the rectangular coils 5SU and 5SL are differentially connected to each other.

[0025] Here, detection of the displacement of the tank 2 relative to the gyro case 1 will be described using the north-side detector 6A as an example. As shown in Figure 2, the winding of the primary coil 4N is located in a plane perpendicular to the spin axis, and is normally excited by an alternating current shared with the gyro power supply PS, generating an alternating magnetic field indicated by the dashed arrow a1.

[0026] When the primary coil 4N is positioned at the center of the four rectangular coils 5NW, 5NE, 5NU, and 5NL of the secondary coil 5N, the magnetic flux from the primary coil 4N passes through the four rectangular coils 5NW, 5NE, 5NU, and 5NL, and the same voltage is induced in the four rectangular coils 5NW, 5NE, 5NU, and 5NL. Therefore, no output voltage is generated at the output terminals 2-1 of the rectangular coils 5NW and 5NE and the output terminals 3-1 of the rectangular coils 5NU and 5NL, which are differentially connected to each other.

[0027] If the secondary coil 5N is displaced horizontally westward (in the direction of arrow W in Figure 2) relative to the primary coil 4N, the magnetic flux from the primary coil 4N that passes through the eastern rectangular coil 5NE increases, increasing its induced voltage, while the magnetic flux that passes through the western rectangular coil 5NW decreases, decreasing its induced voltage. Therefore, a differential voltage is generated at output terminal 2-1 for rectangular coils 5NW and 5NE, but no output voltage is generated at output terminal 3-1 for the vertical rectangular coils 5NU and 5NL.

[0028] If the secondary coil 5N is displaced horizontally eastward relative to the primary coil 4N (in the direction of arrow E in Figure 2), the opposite state occurs to when it is displaced westward. That is, of the magnetic flux generated by the primary coil 4N, the magnetic flux penetrating the western rectangular coil 5NW increases, increasing its induced voltage, while the magnetic flux penetrating the eastern rectangular coil 5NE decreases, decreasing its induced voltage. Therefore, a differential voltage of the opposite polarity to that in the case of westward displacement is generated at output terminal 2-1 for rectangular coils 5NW and 5NE, but no output voltage is generated at output terminal 3-1 for the vertical rectangular coils 5NU and 5NL.

[0029] When the secondary coil 5N is displaced in the vertical direction relative to the primary coil 4N (in FIG. 2, a direction perpendicular to the arrows EW and NS), the magnetic flux from the primary coil 4N that passes through the upper rectangular coil 5NU decreases or increases, and the magnetic flux that passes through the lower rectangular coil 5NL increases or decreases. In this case, the induced voltage in the upper rectangular coil 5NU decreases or increases, and the induced voltage in the lower rectangular coil 5NL increases or decreases, resulting in a differential voltage across the output terminals 3-1 of the vertical rectangular coils 5NU and 5NL.

[0030] In this way, when the north end of the tank 2 on which the primary coil 4N is provided is displaced in the east-west and up-down directions relative to the gyro case 1, a differential voltage is generated at the output terminals 2-1 and 3-1 of the two pairs of rectangular coils 5NW and 5NE, and 5NU and 5NL in the secondary coil 5N. The polarity and magnitude of this differential voltage indicate the direction and magnitude of displacement of the N end of the tank 2. Similarly to the secondary coil 5N, a differential voltage is also generated at the output terminals of the two pairs of rectangular coils 5SW and 5SE, and 5SU and 5SL in the secondary coil 5S, but the voltages due to the rectangular coils 5SW and 5SE and the rectangular coils 5SU and 5SL have polarities opposite to those of the voltages due to the output terminals 2-1 and 3-1.

[0031] (Configuration of the azimuth tracking system) An explanation will be given of the azimuth tracking system according to the first embodiment. Fig. 3 is a schematic diagram showing the configuration of the azimuth tracking system according to this embodiment.

[0032] When the tank 2 undergoes rotational displacement around the vertical axis relative to the gyro case 1, as shown in Figure 3, a differential voltage is generated at the output terminal 2-1 of the rectangular coils 5NW, 5NE and the output terminal 2-2 of the rectangular coils 5SW, 5SE, and a voltage signal is generated at the azimuth output terminal 4-1, which is the output terminal of the rectangular coils 5NW, 5NE, 5SW, and 5SE. This voltage signal generated at the azimuth output terminal 4-1 is applied to the control winding of the azimuth servomotor 19, with or without passing through the azimuth servo amplifier 30. 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. As a result, the tank 2 rotates around the vertical axis, and the relative rotational displacement between the tank 2 and the gyro case 1 becomes zero.

[0033] In this way, the heading tracking system ensures that the heading of the tank 2 always follows the heading of the spin axis of the gyro rotor G, and the N-shape of the compass card 22 always follows the heading of the spin axis of the gyro rotor G. Therefore, the heading of the ship is read from the deviation between the N-shape of the compass card 22 and the baseline 26.

[0034] (Horizontal tracking system configuration) A description will now be given of the horizontal tracking system according to the first embodiment. Fig. 4 is a schematic diagram showing the configuration of the horizontal tracking system according to this embodiment.

[0035] When the tank 2 undergoes rotational displacement around the horizontal axis relative to the gyro case 1, a voltage signal is generated at the horizontal output terminal 5-1, which is the output terminal of the rectangular coils 5NU, 5NL, 5SU, and 5SL. This voltage signal generated at the horizontal output terminal 5-1 is applied to the control winding of the horizontal servo motor 10, with or without passing through the horizontal servo amplifier 31. The rotation of the horizontal servo motor 10 is transmitted to the tank 2 via the horizontal pinion 11 and horizontal gear 9. As a result, the tank 2 rotates around the horizontal axis, and the relative rotational displacement between the tank 2 and the gyro case 1 becomes zero.

[0036] (Guide and vibration control system configuration) The north-pointing and vibration-damping system according to the first embodiment will now be described. FIG. 5 is a schematic diagram showing the north-pointing action of the gyro rotor according to this embodiment. FIG. 6 is a schematic diagram showing the configuration of the vibration-damping system according to this embodiment. Note that FIG. 5 is a schematic diagram showing the gyro case placed inside the tank as seen from the side. Also, FIG. 6 is a schematic diagram showing the detection units provided on the tank and the gyro case.

[0037] The vibration suppression system of the gyrocompass is composed of vibration suppression coils 40N and 40S in the detection units 6A and 6B, respectively, which detect the distance from the primary coils 4N and 4S to detect the amount of movement ξ of the gyro case 1 relative to the tank 2. Therefore, first, this amount of movement ξ will be explained together with the north-pointing action of the gyro rotor G.

[0038] As shown in Figure 5, tank 2 is filled with highly viscous liquid 7, and gyro case 1 is suspended by catenary line 3 while immersed in liquid 7. Here, the center of gravity of gyro case 1 is O1, the center of tank 2 is O2, the connection point between catenary line 3 and tank 2 is P, the connection point between catenary line 3 and gyro case 1 is Q, and the central axis of tank 2 is line PO2 passing through connection point P and center position O2. Furthermore, the points where the spin axis of gyro rotor G intersects with gyro case 1 are A and B, and the two points on tank 2 corresponding to these two points A and B, i.e., the points where the spin axis intersects with tank 2, are A' and B', and the horizontal plane is H-H'. Note that for points A, B, A', and B', points A and A' are designated as the north-facing sides of gyro rotor G.

[0039] When the spin axis of the gyro rotor G is horizontal (θ = 0°), the north-south line A'B' of the tank 2 is aligned with the spin axis, and the center of gravity O1 of the gyro case 1 coincides with the center position O2 of the tank 2. Meanwhile, assume that the spin axis of the gyro rotor G is tilted by an inclination angle θ with respect to the horizontal plane H-H', and that point A on the north side of the gyro case 1 is elevated relative to the horizontal plane H-H'. In this case, the central axis PO2 of the tank 2 is tilted by an inclination angle θ with respect to the vertical line. To reduce this tilt, the tank 2 rotates and tilts around the horizontal axis, following the inclination angle θ of the gyro rotor G, using the horizontal tracking system described above.

[0040] When no external force is acting, the catenary line 3 coincides with the vertical line, and the tension T of the catenary line 3 generates a moment M about the center of gravity O1 for the gyro case 1. If the distance between the center of gravity O1 of the gyro case 1 and the connection position Q of the catenary line 3 on the gyro case 1 is r, and the residual weight of the gyro case 1 excluding the buoyancy due to the liquid 7 is mg, then the moment M acting on the gyro case 1 can be expressed by the formula M = Tr sin θ = mgr sin θ. Here, mgr = K, and K is a northing constant used to correct the horizontal deviation value, which will be described later.

[0041] This moment M acts as a torque on the gyro rotor G around the axis of horizontal axes 8A and 8B passing through the center of gravity O1. In this way, a torque proportional to the tilt angle of the spin axis relative to the horizontal plane can be applied around the horizontal axis of the gyro, generating a north-pointing force. By adjusting the distance r, residual weight mg, and angular momentum of the gyro, the period of the north-pointing motion can be set to several tens to several hundred minutes.

[0042] The gyrocompass vibration damping system is configured to apply a torque around the vertical axis of the gyrocompass proportional to the tilt angle of the spin axis relative to the horizontal plane. The gyro case 1 moves relative to the tank 2 in the direction of point B' on the tank 2 by an amount ξ (O1-O2) until the catenary line 3 coincides with the vertical line. This amount ξ is proportional to the tilt angle θ of the spin axis of the gyro rotor G relative to the horizontal plane H-H'. Therefore, the relative amount ξ of the gyro case 1 is detected by the vibration damping coils 40N, 40S, and the tracking position of the azimuth tracking system is shifted based on this detection amount, twisting the catenary line 3, thereby achieving the desired vibration damping effect.

[0043] Note that because the suspension line 3 has a slight rigidity, when the gyro case 1 tilts with respect to the horizontal plane H-H', it actually describes a bending curve as shown by the suspension line 3'. Therefore, the amount of movement ξ(O1-O2) of the gyro case 1 in the direction of the line A'B' also decreases slightly. However, because the suspension line 3 has sufficient flexibility, the change in this amount of movement is slight, and in practical designs, its impact is small, so the following explanation will ignore this change in the amount of movement.

[0044] As shown in Fig. 6, the vibration suppression system is additionally provided to the azimuth tracking system. Of the detection units 6A and 6B, the primary coils 4N and 4S attached to the outer surface of the gyro case 1 and four pairs of rectangular coils 5NW, 5NE, 5SW, 5SE, 5NU, 5NL, 5SU, 5SL attached to the inner surface of the tank 2 are shown. In addition, the detection units 6A and 6B have a pair of vibration suppression coils 40N and 40S for detecting the above-mentioned amount of movement ξ further north and south of the secondary coils 5N and 5S including these rectangular coils.

[0045] The vibration damping coils 40N, 40S are arranged in parallel with the rectangular coils 5NW, 5NE and 5SW, 5SE arranged in parallel in the horizontal direction in the secondary coils 5N, 5S, and are differentially connected. The vibration damping output terminals 6-1, which are the output terminals of the vibration damping coils 40N, 40S, output a differential voltage proportional to the amount of movement ξ of the gyro case 1. s Output as

[0046] The vibration suppression output terminal 6-1 is additively connected to the azimuth output terminal 4-1, and is connected to the control winding of the azimuth servo motor 19 via the azimuth servo amplifier 30. As a result, the voltage signal applied to the control winding of the azimuth servo motor 19 becomes an excessive voltage signal by the voltage signal from the vibration suppression output terminal 6-1, and the azimuth tracking operation of the tank 2 relative to the gyro case 1 is controlled by the movement detection amount ξ s Displace based on

[0047] The tank 2 is rotated around the vertical axis by the vibration control system by the amount of deviation relative to the operation of the azimuth tracking system, and a torsional stress is generated in the catenary wire 3. As a result, the gyro case 1 detects the amount of movement ξ of the gyro case 1 relative to the tank 2. s The gyro rotor G receives a torsional torque proportional to the rotational speed, and generates a vibration damping effect.

[0048] (Configuration of control unit) The configuration of the control unit according to the first embodiment will be described. FIG. 7 is a block diagram showing the configuration of the control unit according to this embodiment. FIG. 8 shows the offset θ off FIG. 1 is a schematic diagram showing a gyro case in a tank when

[0049] 7, the control unit 33 provided in the gyrocompass has an orientation deviation signal conversion unit 330, a horizontal deviation signal conversion unit 331, a movement amount signal conversion unit 333, an orientation calculation unit 334, a horizontal deviation correction unit 335, a horizontal deviation signal processing unit 336, and an orientation deviation signal processing unit 337. Of these, the orientation calculation unit 334 and the horizontal deviation correction unit 335 are functions realized by calculations performed by the control unit 33.

[0050] The azimuth deviation signal conversion unit 330 converts the voltage output from the azimuth output terminal 4-1, which is the output terminal of the rectangular coils 5NW, 5NE, 5SW, and 5SE, into the azimuth deviation φ s The horizontal deviation signal conversion unit 331 converts the voltage output from the horizontal output terminal 5-1, which is the output terminal of the rectangular coils 5NW, 5NE, 5NU, and 5NL, into the horizontal deviation θ sThe movement amount signal converter 333 converts the voltage output from the vibration suppression output terminal 6-1, which is the output terminal of the vibration suppression coils 40N and 40S, into the movement detection amount ξ s The horizontal deviation signal processing unit 336 receives the horizontal deviation θ corrected by the horizontal deviation correction unit 335 and inputs it to the azimuth calculation unit 334. s ‐ to the horizontal servo amplifier 31. The azimuth deviation signal processing unit 337 converts the azimuth deviation φ output by the azimuth deviation signal conversion unit 330 into s and the detected movement amount ξ output by the movement amount signal conversion unit 333 s is used as input, and the movement detection amount ξ s The azimuth deviation is corrected by the azimuth error correction signal, and the corrected azimuth deviation is output to the azimuth servo amplifier 30.

[0051] The azimuth calculation unit 334 calculates the azimuth deviation φ s and the detected movement amount ξ, which is the detected value in the vibration control system. s Based on the ship's speed V and latitude λ input from an external device of the gyrocompass, the gyrocompass calculates and outputs the direction Φ.

[0052] The horizontal deviation correction unit 335 calculates the offset θ off In addition, the horizontal deviation θ is calculated based on the angular momentum H of the gyro rotor G, the northing constant K, the Earth's rotation speed Ω, and the latitude λ of the current position. s Correct the horizontal deviation θ s ‐ and inputs it to the horizontal deviation signal processing unit 336 as

[0053] The offset θ input to the horizontal deviation correction unit 335 off The horizontal deviation θ corrected by s ‐ is given to the horizontal servo amplifier 31 via the horizontal deviation signal processor 336, and as shown in FIG. 8, the tracking point in the horizontal tracking system is off At this time, the spin axis direction of the gyro case 1 does not change, and the gyro case 1 moves by the movement amount ξ. In other words, the offset θ of the horizontal tracking system offThe amount of movement ξ of the gyro case 1 can be changed by the following. The amount of movement ξ of the gyro case 1 and the tilt angle θ are proportional to each other, so the offset θ of the horizontal tracking system that becomes the desired amount of movement ξ of the gyro case 1 is off is required in advance.

[0054] (Horizontal deviation signal processing section) The configuration of the horizontal deviation signal processor according to the first embodiment will be described below. Fig. 9 is a control block diagram showing the configuration of the horizontal deviation signal processor according to this embodiment using a Laplace operator.

[0055] As shown in FIG. 9, the horizontal deviation signal processing unit 336 converts the horizontal deviation θ s ‐ is the target value, and the horizontal deviation θ s The horizontal servo gain K a , horizontal servo controller C1(s) including PID control, and horizontal servo motor gain K VF and horizontal movement gain K x and a horizontal displacement controller C2(s) including PID control. x 9, 1 / N is the horizontal gear ratio, which is the ratio between the horizontal pinion 11 and the horizontal gear, and τ G is the time constant of the first delay.

[0056] The offset θ input to the horizontal deviation correction unit 335 off The detected movement amount ξ of the gyro case 1 is output via the horizontal deviation signal processing unit 336. s However, it takes several seconds to several minutes after tracking starts for the amount of movement ξ and the tilt angle θ to become proportional to each other.

[0057] Horizontal deviation θ of Tank 2 relative to Gyro Case 1 sEven in a gyrocompass equipped with a horizontal tracking system that maintains a relative attitude based on the horizontal displacement, a change in the displacement at the start of tracking causes a transient disturbance torque to act on the gyro case 1 via the viscosity of the liquid 7 in the tank 2, and the movement amount ξ also changes, and it takes time for the proportional relationship between the movement amount ξ, which is not subject to control by the gyro case 1, and the tilt angle θ to be established. The horizontal movement amount calculation unit 336A can shorten the time until such a proportional relationship is established.

[0058] The horizontal movement amount calculation unit 336A calculates the detected movement amount ξ s is input, and the offset ξ of the preset movement amount ξ off Based on the northing constant K, the angular momentum H of the gyro rotor G, and the Earth's rotation speed Ω, the horizontal movement amount gain Kx and the horizontal movement amount controller C2(s) calculate the movement detection amount ξ s The target value is the moving target amount ξ s ‐ Here, the target movement amount ξ s ‐ teeth,

[0059]

number

[0060] As will be described later, the horizontal movement amount calculation unit 336A establishes a proportional relationship between the movement amount ξ and the tilt angle θ so that the transient response after tracking starts converges, prior to the calculation of the direction Φ by the direction calculation unit 334. This allows the gyrocompass to start compass calculation from the desired north-pointing attitude, and the amplitude of the north-pointing motion is suppressed. Furthermore, because there is no need to add a separate hardware element to the gyrocompass to establish a proportional relationship between the movement amount ξ and the tilt angle θ, the gyrocompass can be used as a compass at low cost and in a short time.

[0061] (Horizontal movement amount control processing) The operation of the horizontal movement amount control processing according to the first embodiment will be described. Fig. 10 is a flowchart showing the operation of the horizontal movement amount control processing. In the flowchart shown in Fig. 10, the operation of the horizontal deviation signal processing unit and the azimuth deviation signal processing unit has already started, and the operation shown in Fig. 10 is executed before the azimuth calculation unit calculates the azimuth.

[0062] 10, the horizontal deviation signal processor 336 determines whether the elapsed time t from the start of operation of the horizontal deviation signal processor 336 and the azimuth deviation signal processor 337 is less than a preset time threshold t1 (S101). Here, the time threshold t1 is set to, for example, between 0 seconds and 10 minutes.

[0063] If the elapsed time t is less than the time threshold value t1 (S101, YES), the horizontal deviation signal processing unit 336 outputs the above-mentioned movement detection amount ξ s (S102), and the control of the detected movement amount ξ s It is determined whether or not the value is within a first range set in advance (S103).

[0064] Movement detection amount ξ s is within the first range (S103, YES), the horizontal deviation signal processing unit 336 calculates the horizontal deviation θ s It is determined whether or not the value is within a second range set in advance (S104).

[0065] Horizontal deviation θ s is within the second range (S104, YES), the horizontal deviation signal processing unit 336 outputs the detected movement amount ξ s The control is then terminated (S105), and the horizontal movement amount control process is terminated.

[0066] On the other hand, the horizontal deviation θ s If the horizontal deviation signal processing unit 336 determines again whether the elapsed time t is less than the preset time threshold value t1 (S101), the horizontal deviation signal processing unit 336 determines whether the elapsed time t is less than the preset time threshold value t1 (S101).

[0067] In step S103, the detected movement amount ξ s is not within the first range (S103, NO), the horizontal deviation signal processing unit 336 again determines whether the elapsed time t is smaller than the preset time threshold value t1 (S101).

[0068] In step S101, if the elapsed time t is not less than the time threshold value t1 (S101, NO), the horizontal deviation signal processing unit 336 outputs the detected movement amount ξ s The control is then terminated (S105), and the horizontal movement amount control process is terminated.

[0069] According to this horizontal movement amount control process, the detected movement amount ξ s , horizontal deviation θ s When the movement detection amount ξ approaches a desired value that falls within a set range, or exceeds a time threshold t1, s As a result, even if the elapsed time t exceeds the time threshold t1, the movement detection amount ξ s , horizontal deviation θ s If is not within the range, the direction calculation unit 334 calculates the direction Φ.

[0070] Second Embodiment A gyrocompass according to a second embodiment will be described. Fig. 11 is a block diagram showing the configuration of a control unit according to this embodiment. Fig. 12 is a control block diagram showing the configuration of a horizontal deviation signal processing unit according to this embodiment using a Laplace operator.

[0071] As shown in FIGS. 11 and 12, the gyrocompass according to this embodiment includes a horizontal deviation signal processor 336 that processes the moving target amount ξ calculated by the equation (1). s ‐ Instead of the set value ξ stored in advance in the storage device 39, m The target amount of movement is ξ s ‐ The gyrocompass according to the first embodiment differs from the gyrocompass according to the first embodiment in that the storage device 39 may be a storage device that stores various data required for the processing operations of the control unit 33, and a part of the storage device 39 stores the set value ξm The set value ξ may be stored. m is the amount of movement detected when the ship equipped with the gyrocompass is stopped, the gyrocompass is stopped, and the ship is pointing north. s As a result, the horizontal deviation signal processing unit 336 according to this embodiment calculates the moving target amount ξ s ‐ It is possible to make the gyrocompass usable without calculating

[0072] The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. These novel embodiments may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0073] 1 Gyro Case 2 Tanks 3 Suspension line (support part) 336 Horizontal deviation signal processing unit 336A Horizontal movement amount calculation section

Claims

1. a gyro case with a built-in gyro rotor; a tank that houses the gyro case therein; a support unit that supports the tank and has degrees of freedom about three axes including a first axis that faces a spin axis direction of the gyro rotor, a second axis that is orthogonal to the first axis and parallel to a horizontal plane, and a third axis that is orthogonal to the first axis and the second axis; a detection unit that detects a displacement of the attitude and position of the gyro case relative to the tank in a non-contact manner; a horizontal tracking system that causes the tank to track around the second axis so as to maintain the attitude of the tank relative to the gyro case based on a displacement amount that is a displacement of the attitude of the gyro case around the second axis detected by the detection unit, the horizontal tracking system having a horizontal movement amount calculation unit that controls a movement detection amount that is a movement amount of the tank detected by the detection unit to a movement target amount; A gyrocompass equipped with a

2. The horizontal movement amount calculation unit is ｓ is the detected movement amount, ξ ｓ ‐ is the moving target amount, λ is the latitude of the current position of the gyrocompass, and ξ ｏｆｆ is a preset offset of the movement amount, H is the angular momentum of the gyro rotor, K is a north-pointing constant, and Ω is the Earth's rotation speed, [Equation 1] 2. The gyrocompass according to claim 1, wherein the detected amount of movement is controlled to the target amount of movement expressed by:

3. The tank is filled with a liquid, the support portion is a string-like member, the gyro case is suspended and supported by the support portion while being immersed in the liquid and is housed in the tank, 3. The gyrocompass according to claim 2, wherein the north-pointing constant is expressed as K=mgr, where r is the distance between the center of gravity of the gyro case and the connection position of the string-like member on the gyro case, and mg is the remaining weight of the gyro case excluding the buoyancy of the liquid.

4. 2. The gyrocompass according to claim 1, wherein the horizontal movement amount calculation unit sets the movement amount stored when the gyrocompass is stopped and pointing north as the movement target amount.

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