IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0211788
(1980-12-01)
|
우선권정보 |
DE-0048051 (1979-11-29) |
발명자
/ 주소 |
- Riethmuller, Heinz
- Sindlinger, Rainer
- Schultz, Peter
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
6 인용 특허 :
3 |
초록
▼
A gyrocompass including a first gimbal, a gyro motor mounted in the first gimbal and including a gyro rotor mounted to rotate about a horizontally alignable spin axis, a pendulous body in which the first gimbal is mounted to be rotatable about a vertically alignable axis of rotation, a housing in wh
A gyrocompass including a first gimbal, a gyro motor mounted in the first gimbal and including a gyro rotor mounted to rotate about a horizontally alignable spin axis, a pendulous body in which the first gimbal is mounted to be rotatable about a vertically alignable axis of rotation, a housing in which the body is rotatably suspended, a verticality device associated with the body for allowing the body to assume an orientation in the housing in which the axis of rotation is vertical, and a follow-up device including a pickup mounted for sensing the angular position, about the axis of rotation, of the gimbal relative to the body and a drive connected for rotating the body relative to the housing about the axis of rotation in dependence on the position sensed by the pickup. The drive can be constituted by a stepping motor constructed to rotate in highly uniform steps and simultaneously serving to provide an indication of the angular position of the body relative to the housing about the axis of rotation. Alternatively, the drive can be constituted by a stepping motor constructed to rotate in highly uniform steps, the follow-up device can include a restraining circuit and a torquer connected between the pickup and the first gimbal for restraining the first gimbal at a defined angular position, about the axis of rotation, relative to the body, the restraining circuit providing a signal representative of the angular velocity of the first gimbal about the axis of rotation, and the gyrocompass can further include a unit for determining the direction to true north from signals representative of the angular velocity.
대표청구항
▼
1. In a gyrocompass including a first gimbal, a gyro motor mounted in the first gimbal and including a gyro rotor mounted to rotate about a horizontally alignable spin axis, a body in which the first gimbal is mounted to be rotatable about a vertically alignable axis of rotation, a housing in which
1. In a gyrocompass including a first gimbal, a gyro motor mounted in the first gimbal and including a gyro rotor mounted to rotate about a horizontally alignable spin axis, a body in which the first gimbal is mounted to be rotatable about a vertically alignable axis of rotation, a housing in which the body is rotatably suspended, a verticality device associated with the body for allowing the body to assume an orientation in the housing in which the axis of rotation is vertical, and a follow-up device including a pickup mounted for sensing the angular position, about the axis of rotation, of the gimbal relative to the body and a drive connected for rotating the body relative to the housing about the axis of rotation in dependence on the position sensed by the pickup, the improvement wherein said drive comprises a stepping motor constructed to rotate in highly uniform steps and simultaneously serving to provide an indication of the angular position of said body relative to said housing about said axis of rotation. 2. Gyrocompass as defined in claim 1 further comprising a cardan joint suspending said body in said housing. 3. Gyrocompass as defined in claim 2 wherein said cardan joint is firmly connected to said housing and said stepping motor is diposed between said cardan joint and said body. 4. Gyrocompass as defined in claim 2 or 3 wherein said stepping motor is a flat plate motor having a stator connected to said cardan joint, a rotor connected to said body, and a bearing rotatably supporting both said rotor and said body. 5. Gyrocompass as defined in 1, 2 or 3 claim wherein said stepping motor is provided with meshing rings of teeth on said stator and said rotor, each ring being composed of a large number of teeth, with the teeth on one ring differing from those on the other ring by at least one, and the ring of teeth of said rotor being arranged to be yielding in the direction of the axis of rotation and to be stiff in the circumferential direction of said motor. 6. Gyrocompass as defined in claim 1, 2 or 3 wherein said verticality device comprises an electrically actuatable electromagnet which is disposed at the lower end of said body being pendulous body and having an armature and said housing has a calotte-shaped part with which said armature is in contact temporary. 7. In a gyrocompass including a first gimbal, a gyro motor mounted in the first gimbal and including a gyro rotor mounted to rotate about a horizontally alignable spin axis, a body in which the first gimbal is mounted to be rotatable about a vertically alignable axis of rotation, a housing in which the body is rotatably suspended, a verticality device associated with the body for allowing the body to assume an orientation in the housing in which the axis of rotation is vertical, a follow-up device including a pickup mounted for sensing the angular position, about the axis of rotation, of the gimbal relative to the body, and a drive connected for rotating the body relative to the housing about the axis of rotation in dependence on the position sensed by the pickup, the improvement wherein: said drive comprises a stepping motor for rotating the body with highly uniform steps in defined positions; said follow-up device further comprises a restraining circuit and a torquer connected between said pickup and said first gimbal for restraining said first gimbal at a defined angular position, about the axis of rotation, relative to said body, said restraining circuit providing a signal representative of the angular velocity of said first gimbal about the axis of rotation; and said gyrocompass further comprises means for determining the direction to true north from signals representative of said angular velocity. 8. Gyrocompass as defined in claim 7 wherein said determining means comprise a data processor connected to receive signals representative of said angular velocity and of the angular position of said body about the axis of rotation, and to provide an indication of the north direction from such signals. 9. Gyrocompass as defined in claim 7 or 8 wherein the length of each step rotation imposed on said body by said stepping motor is relatively large, while the reproduceable setting accuracy is of the order of magnitude of the desired measuring accuracy of said gyrocompass. 10. Gyrocompass as defined in claim 7 wherein said follow-up device comprises an electronic actuating system connected for supplying drive signals to said stepping motor and a zero position pickup connected for providing an indication when said motor is at a predetermined zero angular position, the actual angular position of said motor being determined from the signals from said electronic actuating system and from said zero position pickup. 11. Method for operating a gyrocompass which is composed of a first gimbal, a gyro motor mounted in the first gimbal and including a gyro rotor mounted to rotate about a horizontally alignable spin axis, a body in which the first gimbal is mounted to be rotatable about a vertically alignable axis of rotation, a housing in which the body is rotatably suspended, a verticality device associated with the body for allowing the body to assume an orientation in the housing in which the axis of rotation is vertical, a follow-up device including a pickup mounted for sensing the angular position, about the axis of rotation, of the first gimbal relative to the body, and a drive connected for rotating the body relative to the housing about the axis of rotation in dependence on the position sensed by the pickup, and in which said drive comprises a stepping motor for rotating said body with highly uniform steps in defined positions, said follow-up device further includes a restraining circuit and a torquer connected between said pickup and said first gimbal for restraining said first gimbal at a defined angular position, about the axis of rotation, relative to said body, said restraining circuit providing a signal representative of the angular velocity of said first gimbal about the axis of rotation, and said gyrocompass further includes means for determining the direction to true north from signals representative of said angular velocity, said method comprising: rotating said body, by means of said stepping motor, about the axis of rotation, to at least two successive, mutually spaced, arbitrary angular positions; effecting first measurements of the angular velocity of said first gimbal about the axis of rotation at each of the angular positions; deriving from the angular velocity measurements a first estimated value for the azimuth angle between the spin axis and north for one of the arbitrary angular positions; and thereafter rotating said gyro motor by means of said stepping motor about the axis of rotation through an angle dependent of the estimated azimuth angle value in such a manner as to achieve a rough alignment of the spin axis with the north direction. 12. Method as defined in claim 11 wherein said step of rotating is carried out to rotate said body between two angular positions which are about 90° apart and said step of deriving the first estimated value is carried out by determining the value of ##EQU## where ω 1 and ω 2 are the angular velocity values measured at the two angular positions, respectively, and D* is representative of the value of gyro drift. 13. Method as defined in claim 11 or 12 wherein the stepping motor can be rotated over a finite angular range of equal to or greater than 360° and said step of rotating is carried out to cause the second angular position to be at least approximately in the area of the middle of the angular range. 14. Method as defined in claim 11 or 12 wherein said first measurement at each angular position is made over a preselected period of time of a few seconds, and is obtained by deriving a number of individual measured values at regular intervals and deriving each angular velocity value by filtering and/or average formation of the associated individual measured values. 15. Method as defined in claim 12 further comprising deriving an approximate value for the horizontal component of the earth's rotation by determining the value of ##EQU## 16. Method as defined in claim 11 further comprising, after said step of rotating said gyro motor to achieve a rough alignment, restraining the spin axis in this position by means of said restraining circuit; effecting a first fine measurement of the angular velocity of said first gimbal; and making a first determination of the north deviation of said spin axis by determining the value of ##EQU## where ω 3 is the angular velocity value obtained by said first fine measurement, D* is representative of gyro drift, and Ω H is an at least approximate value for the horizontal component of the earth's rotation. 17. Method as defined in claim 16 wherein said first fine measurement is made over a preselected period of time and is obtained by deriving a number of individual measured values at regular intervals and deriving the associated angular velocity value by filtering and/or average formation of the individual measured values. 18. Method as defined in claim 17 wherein said step of deriving the associated angular velocity values is carried out by smoothing the individual measured values in a lowpass filter. 19. Method as defined in claim 18 further comprising increasing the time constant of the lowpass filter during the preselected period of time. 20. Method as defined in claim 17, 18 or 19 wherein said step of deriving the associated angular velocity value is carried out by disregarding each individual measured value which differs from the filtered average of all preceding measured values by more than a predetermined amount. 21. Method as defined in claim 20 wherein said step of deriving the associated angular velocity value comprises reducing the magnitude of the predetermined amount during the preselected period of time. 22. Method as defined in claim 20 wherein said step of deriving the associated angular velocity value comprises determining the magnitude of the predetermined amount for at least one measured value as a function of the range covered by the preceding individual values. 23. Method as defined in claim 20 wherein said step of deriving the associated angular velocity value comprises varying the duration of the preselected period of time as a function of the range covered by the preceding measured values. 24. Method as defined in claim 16 further comprising, after said step of determining the north deviation: rotating said body by means of said stepping motor, about the axis of rotation through a predetermined angle; effecting a second fine measurement of the angular velocity of said first gimbal; and determining constant components of interfering moments in the measured values from the first and second fine measurements. 25. Method as defined in claim 24 wherein the predetermined angle is 180°. 26. Gyrocompass as defined in claim 24 wherein said second fine measurement is made over a preselected period of time and is obtained by deriving a number of individual measured values at regular intervals and deriving the associated angular velocity value by filtering and/or average formation of the individual measured values. 27. Method as defined in claim 24, 25 or 26 further comprising, after said step of effecting a second fine measurement, making a second determination of the north deviation of said spin axis by determining the value of ##EQU## where ω 4 is the angular velocity value obtained by said second fine measurement. 28. Method as defined in claim 24, 25 or 26 further comprising after said step of effecting a second fine measurement: determining the value of gyro drift by determining the value of (ω 3 +ω 4 )/2, where ω 4 is the angular velocity value obtained by said second fine measurement; and using the determined gyro drift value in subsequent determinations which take account of gyro drift. 29. Method as defined in claim 11 further comprising, after said step of deriving: rotating said first gimbal about the axis of rotation to at least an angular position which is offset from north by a selected angle; and effecting a further measurement of the angular velocity of said first gimbal about the axis of rotation, and wherein each said step of effecting measurement is carried out by generating, in an A/D converter, a digital value representative of an associated angular velocity value, and additionally comprising using the digital value associated with the further measurement to determine the incremental change in digital values. 30. Method as defined in claim 29 wherein each said step of effecting measurement is carried out in a circuit which includes the A/D converter and which has a total gain represented by the ratio of each angular velocity value to its associated digital value, and further comprising determining the value of the total gain by determining the ratio of the difference between two measured angular velocity values and the difference between the two corresponding digital values. 31. A method as defined in claim 11 or 12 further comprising, after said step of making a first determination: rotating said body about the axis of rotation, to two successive further angular positions corresponding exactly to the estimated value plus and minus 90°, respectively; effecting measurement of the angular velocity of said first gimbal at each further angular position by generating a digital value representative of each angular velocity value, in a circuit which includes an A/D converter and which has a total gain represented by the ratio of each angular velocity value to its associated digital value; and determining the value of such total gain by determining the value of the ratio of two times the horizontal component of the earth's rotation to the difference between the digital values generated for each further angular position. 32. Method as defined in claim 11 wherein said steps of deriving and rotating are performed by the operation of a microprocessor.
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