IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
UP-0595621
(2004-10-29)
|
등록번호 |
US-7661627
(2010-04-03)
|
우선권정보 |
FR-03 12914(2003-11-04) |
국제출원번호 |
PCT/FR2004/002800
(2004-10-29)
|
§371/§102 date |
20060614
(20060614)
|
국제공개번호 |
WO05/045366
(2005-05-19)
|
발명자
/ 주소 |
- Defendini, Ange
- Ghezal, Mehdi
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
4 인용 특허 :
4 |
초록
▼
A method of controlling the attitude of a satellite (1) including two gyrodynes (3,4) and a third main actuator (2) which delivers torques at least along the Z axis. The method includes: fixing the gimbal axes, A1 and A2, of the gyrodynes (3, 4) parallel to Z; setting a non-zero bias (α) betwe
A method of controlling the attitude of a satellite (1) including two gyrodynes (3,4) and a third main actuator (2) which delivers torques at least along the Z axis. The method includes: fixing the gimbal axes, A1 and A2, of the gyrodynes (3, 4) parallel to Z; setting a non-zero bias (α) between the angular momentum vectors (Formula I) of the gyrodynes; using the measurements provided by the sensors on board the satellite to estimate the kinematic and dynamic variables necessary in order to control the attitude of the satellite (1); calculating set variables in order to the objectives assigned to the satellite (1) attitude control system; and using the deviations between the estimated variables and the set variables to calculate control orders and to send same to the main actuators (2, 3, 4).
대표청구항
▼
The invention claimed is: 1. A method for controlling the attitude of a satellite equipped with an attitude control system in a reference coordinate system (X, Y, Z) fixed with respect to the satellite for positioning the satellite, the method comprising: providing the attitude control system that
The invention claimed is: 1. A method for controlling the attitude of a satellite equipped with an attitude control system in a reference coordinate system (X, Y, Z) fixed with respect to the satellite for positioning the satellite, the method comprising: providing the attitude control system that comprises: only three primary actuators including two control moment gyros and one Z-axis actuator, the two control moment gyros each comprising: a rotor connected to a steerable gimbal, each rotor having a fixed axis with respect to the steerable gimbal, each gimbal having a fixed axis with respect to the satellite, the fixed axis of each rotor being perpendicular with respect to the fixed axis of its connected gimbal, the gimbal axes being parallel to each other and the Z-axis, each rotor driven to rotate about its fixed axis to orient its connected steerable gimbal about the fixed axis of said gimbal, the Z-axis actuator delivering torque in at least one direction not lying in a (X, Y) plane, the angular momentum vectors (H1, H2) of the control moment gyros move in the (X, Y) plane and define between them an angle (α) which is related to a skew angle (ε), wherein ε=180−α between the angular momentum vectors (H1, H2) when α is greater than 0° and less than 180°; wherein the method further comprises the following steps: providing a set of secondary actuators used to achieve the offloading of the primary actuators; the secondary actuator being chosen among magnetic torquers, jet actuators, steerable reflecting ailerons or tabs; the method comprises an initialization phase during which the secondary actuators are operated in order to generate an angular momentum in at least one direction in the (X,Y) plane for bringing the pair of control moment gyros into a configuration in which the angle (α) has a value different from 0° and 180°; the method further comprising the steps of: using the Z-axis actuator for delivering torques in at least one direction not lying in the (X, Y) plane; imparting nonzero skew angle (ε) between the angular momentum vectors (H1, H2) of the control moment gyros; estimating kinematic and dynamic variables of the satellite along the X, Y and Z axes from measurements provided by sensors disposed on board the satellite; calculating setpoint variables for controlling a desired attitude of the satellite with respect to the three axes of the (X, Y, Z) coordinate system; and calculating control commands from differences between said estimated kinematic and dynamic variables and said setpoint variables, the control commands comprising commands to vary the orientation of the gimbal axes of the control moment gyros; sending the calculated control commands to the three primary actuators; sending commands to the secondary actuators to modify the angle (α) between the angular momentum vectors (H1 and H2) of the control moment gyros so that said angle (α) remains within a specified range that includes neither 180° nor 0°. 2. The control method as claimed in claim 1, wherein the Z-axis actuator comprises one reaction wheel. 3. The control method as claimed in claim 1, wherein a total angular momentum of the two control moment gyros, resulting from the skew (ε) angle between the angular momentum vectors (H1, H2) of said control moment gyros, is oriented in a direction normal to the orbital plane of the satellite. 4. The control method as claimed in claim 1, wherein a total angular momentum of the two control moment gyros, resulting from the skew (ε) angle between the angular momentum vectors (H1, H2) of the two control moment gyros, is compensated for by the projection in the (X,Y) plane of the cumulative specific moment by the Z-axis actuator. 5. The control method as claimed in claim 1 further comprising: establishing a setpoint configuration for the two control moment gyros from initial and final conditions of the satellite so that an angular momentum exchange between the satellite and the two control moment gyros is brought into said setpoint configuration and generating a desired attitude maneuver with the Z-axis actuator, the Z-axis actuator comprising a reaction wheel; and rotating the rotors using an open-loop servocontrol to orient each gimbal within the setpoint configuration; and generating a Z-axis angular momentum profile by varying a speed of the reaction wheel. 6. The control method as claimed in claim 5, further comprising: adding closed-loop commands to the open-loop servocontrol. 7. The control method as claimed in claim 1, further comprising: using the at least one secondary actuator to generate torques along one or more of the X, Y or Z, axes of the reference coordinate system, and desaturating the Z-axis actuator. 8. The control method of claim 1, wherein the kinematic and dynamic variables comprise attitude angles and angular velocities of the satellite. 9. The control method as claimed in claim 1, wherein the commands to vary the orientation of the gimbal axes of the control moment gyros comprise gimbal angular position setpoints that have been generated by a local feedback control in position or electric current setpoints, for currents that have been injected into motors for orientating the gimbal axes.
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