US3813067A
Expired / Lapsed
US
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Attitude stabilization system
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1972-06-29
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Granted: 1974-05-28
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Expires: 1992-06-29
Abstract
Abstract An attitude stabilization and control system is disclosed for providing accurate control and stabilization of a space vehicle traveling in a circular or near circular orbit relatively to a body such as the earth. A reaction wheel operated at a modulated bias speed is mounted in a gimbal system having two axes of freedom. The speed of the wheel and the gimbal angles are controlled by electronically implemented logic based upon only two-axis attitude error sensing to provide three-axis stabilization and control in the presence of disturbances. Secular disturbances cause growth in the gimbal angles and the wheel speed and are intermittently compensated by actuation of small thrusters or magnetic coils.
Inventors
- 👤 H Mork
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:53
CPC Classifications
B; B64; B64G; B64G1/00; B64G1/22; B64G1/24; B64G1/36; B64G1/28; B64G1/283; B64G1/285
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
284 words
An attitude stabilization and control system for a space vehicle traveling in an orbit about a body, the vehicle having orthogonal axes defined such that a pitch axis is nominally perpendicular to the orbit plane, a yaw axis nominally intercepts the center of the orbited body, and a roll axis nominally coincides with the velocity vector, the axes to have a preferred position with respect to the body, the system comprising: a pitch orientation sensor having an output representative of the angular deviation of the vehicle from a stabilized position about the pitch axis; a roll orientation sensor having an output representative of the angular deviation of the vehicle fromthe stabilized position about a roll axis; a source of momentum directed along each of the reference axes and having a bias value along the pitch axis; means operable on said momentum source for independently changing the momentum along each of the reference axes; momentum measuring means associated with said momentum source for providing momentum output signals representative of the instantaneous momentum along the reference axes; pitch control logic means having inputs coupled to said pitch sensor, to the output of s aid momentum measuring means representative of pitch momentum, and an output coupled to said momentum source, through said pitch momentum changing means, for variably controlling the pitch momentum; and yaw and roll control logic means coupled to said roll sensor and to the outputs of said mementum measuring means representative of yaw and pitch momentum, and having outputs coupled to said momentum source, through said yaw and roll momentum changing means, for variably controlling the roll and yaw momenta thereby producing reaction torques which substantially reorientate the vehicle to the preferred stabilized orientation.
Claim 2
Dependent Claim
284 words
An attitude stabilization and control system for a space vehicle traveling in an orbit about a body, the vehicle having orthogonal axes defined such that a pitch axis is nominally perpendicular to the orbit plane, a yaw axis nominally intercepts the center of the orbited body, and a roll axis nominally coincides with the velocity vector, the axes to have a preferred position with respect to the body, the system comprising: a pitch orientation sensor having an output representative of the angular deviation of the vehicle from a stabilized position about the pitch axis; a roll orientation sensor having an output representative of the angular deviation of the vehicle fromthe stabilized position about a roll axis; a source of momentum directed along each of the reference axes and having a bias value along the pitch axis; means operable on said momentum source for independently changing the momentum along each of the reference axes; momentum measuring means associated with said momentum source for providing momentum output signals representative of the instantaneous momentum along the reference axes; pitch control logic means having inputs coupled to said pitch sensor, to the output of s aid momentum measuring means representative of pitch momentum, and an output coupled to said momentum source, through said pitch momentum changing means, for variably controlling the pitch momentum; and yaw and roll control logic means coupled to said roll sensor and to the outputs of said mementum measuring means representative of yaw and pitch momentum, and having outputs coupled to said momentum source, through said yaw and roll momentum changing means, for variably controlling the roll and yaw momenta thereby producing reaction torques which substantially reorientate the vehicle to the preferred stabilized orientation.
Claim 3
Dependent Claim
110 words
The attitude stabilization and control system of claim 1 wherein said pitch control logic means and said yaw and roll control logic means include means for generating momentum command signals in accordance with: Hwxc K1 phi + Integral (K2 phi + omega oHwz)dt, Hwyc - HB K5 theta + K6 Integral theta dt, Hwzc HB phi - omega o Integral (Hwx + K4''(-Hwz + HB phi ))dt - K4'' Hwx where Hwxc, Hwyc, Hwzc are commanded momenta along roll, pitch and yaw, respectively, Hwx, Hwz are measured roll and yaw momenta, respectively, HB is pitch momentum bias, omega o is orbital rate, K1, K2, K4'', K5, K6 are control gains.
Claim 4
Dependent Claim
57 words
The attitude stabilization and control system of claim 2 further comprising: reaction means for producing control torque on the vehicle, and momentum unloading logic means coupled to said reaction means, to said pitch control logic means, and to said yaw and roll control logic means for actuating said reaction means in response to predetermined stored momentum conditions.
Claim 5
Dependent Claim
120 words
The attitude stabilization and control system of claim 1 wherein: said source of momentum includes a reaction wheel; said yaw and roll momentum changing means comprises: yaw and roll gimbal means coupled to said reaction wheel and imparting two degrees of freedom thereto; and yaw and roll gimbal drive means coupled to each said gimbal means for selectively positioning each gimbal means; said pitch momentum changing means comprises drive means coupled to said reaction wheel for operating the wheel at selected angular speeds; and said momentum measuring means includes: sensing means for generating a signal representative of wheel speed; and indicating means coupled to each said gimbal means for generating signals representative of the position of each said gimbal means.
Claim 6
Dependent Claim
57 words
The attitude stabilization and control system of claim 4 further comprising: reaction means for producing control tOrques on the vehicle, and momentum unloading logic means coupled to said reaction means, to said pitch control logic means, and to said yaw and roll control logic means for actuating said reaction means in response to predetermined stored momentum conditions.
Claim 7
Dependent Claim
79 words
The attitude stabilization and control system of claim 5 wherein said reaction means includes: pitch thrusters, and roll thrusters and said momentum unloading logic means includes: a first threshold circuit coupled to said pitch control logic means responsive to the differential wheel speed, and a second threshold circuit coupled to said yaw and roll control logic means responsive to a yaw gimbal position signal whereby said thrusters may be actuated at predetermined values of the yaw gimbal position signal.
Claim 8
Dependent Claim
142 words
The attitude stabilization and control system of claim 4 wherein said yaw and roll control logic means includes means for generating the yaw and roll gimbal command signal in accordance with: gamma zc K1'' phi + Integral (K2'' phi - omega o gamma x)dt + (1/HB) Integral Tau mxdt gamma xc - phi K4'' gamma z - Integral ( omega o gamma z + omega oK4'' ( gamma x + phi ) - Tau mz/HB - K4'' Tau mx/HB) dt where phi is a roll axis deviation angle, gamma x and gamma z are deviations of the gimbal means from a predetermined position, omega o is the orbital rate of the vehicle about the body, HB is the bias momentum of the reaction wheel, and gamma mx and gamma mz are momentum control torques on the vehicle produced by said reaction means.
Claim 9
Dependent Claim
40 words
The attitude stabilization and control system of claim 7 further comprising: torque compensation logic means coupled to said yaw and roll control logic means for generating signals representative of estimated torques on the vehicle due to disturbances not otherwise measured.
Claim 10
Dependent Claim
89 words
The attitude stabilization and control system of claim 8 wherein said yaw and roll control logic means includes further means for generating the yaw and roll gimbal command signals in accordance with: gamma zc K1'' phi + Integral (K2'' phi - omega o gamma x)dt + (1/HB) Integral ( Tau dx + Tau mx)dt and gamma xc - phi - K4'' gamma z - Integral ( omega o gamma z + omega oK4''( gamma x + phi ) (1/HB)( Tau dz Tau mz) -(K4'' /HB)( Tau dx Tau mx))dt
Claim 11
Dependent Claim
57 words
The attitude stabilization and control system of claim 1 further comprising: reaction means for producing control torque on the vehicle, and momentum unloading logic means coupled to said reaction means, to said pitch control logic means, and to said yaw and roll control logic means for actuating said reaction means in response to predetermined stored momentum conditions.
Claim 12
Dependent Claim
157 words
The attitude stabilization and control system of claim 10 wherein said pitch control logic means and said yaw and roll control logic means includes means for generating momentum command signals in accordance with: H=hd wxc K1 phi + Integral (K2 phi + omega oHwz)dt + Integral Tau mxdt + Integral Tau dxdt, Hwyc - HB K5 theta + K6 Integral theta dt, Hwzc HB phi - omega o Integral (Hwx + K4''(- Hwz + HB phi )) dt, - K4''Hwx + Integral ( Tau mz + K4'' Tau mx)dt + Integral ( Tau dz + K4'' Tau dx)dt, where Hwxc, Hwyc, Hwzc are commanded momenta along roll, pitch and yaw, respectively, H=wx, Hwz are measured roll and yaw momenta, respectively, HB is pitch momentum bias, omega o is orbital rate, K1, K2, K4'', K5, K6 are control gains, Tau my and Tau mz are momentum unloading torques, and Tau dx and Tau dz are estimated disturbance torques.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-27 | 1977-11-26 | 1978-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-27 | 1981-11-26 | 1982-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-27 | 1985-11-26 | 1986-05-28 | $7700.00 | Window Closed / Lapsed |