Saturation control based redundant reaction flywheel torque adaptive allocation method

Abstract

The application discloses a redundant reaction flywheel torque adaptive distribution method based on saturation control, which comprises the following steps: (1) starting, setting saturation threshold and reset threshold of each flywheel; (2) starting control mode; (3) detecting attitude error and angular velocity error of the aircraft, and calculating expected torque by PID; (4) detecting rotating speed of each flywheel; (5) comparing the rotating speed with the saturation threshold and the reset threshold, and screening available flywheels; (6) prioritizing the flywheels; (7) distributing torque according to the expected torque and the flywheel priority, when it is single-flywheel mode, executing step (8); when it is multi-flywheel mode, executing step (9); when it is degradation mode, executing step (10); (8) enabling the flywheel with the highest priority to output the expected torque, and jumping to step (10); (9) distributing the expected torque to each flywheel averagely, and jumping to step (11); (10) enabling all available flywheels to output at full power; and (11) ending.

Description

Technical Field

[0001] This invention relates to the technical field of attitude control for spacecraft, and in particular to an adaptive distribution method for redundant reaction flywheel torque based on saturation control. Background Technology

[0002] Spacecraft attitude control systems often use reaction flywheels as actuators. By changing the rotational speed of the reaction flywheel, control torque is generated to achieve attitude adjustment and stability maintenance of the spacecraft on three axes. To improve reliability, redundant reaction flywheels are usually set on each attitude axis so that the system still has control capability when some reaction flywheels are active or saturated. The reaction flywheel has a maximum torque and a maximum allowable speed (protection speed) limit. When the speed approaches the protection speed, measures such as momentum unloading or reaction flywheel switching need to be taken to prevent the reaction flywheel from being overloaded and damaged.

[0003] In existing technologies, multi-reaction flywheel redundancy systems typically employ a fixed master / slave mode or a simple switching strategy. This means that only one master reaction flywheel is activated for each attitude axis, with the backup flywheel only being used after the master flywheel fails or becomes saturated. This approach presents two problems: first, switching lag can lead to insufficient attitude control torque, affecting control accuracy; second, redundant reaction flywheels remain idle during normal operation, resulting in low resource utilization. Furthermore, when multiple reaction flywheels simultaneously approach saturation or fail, existing methods lack a dynamic allocation mechanism for the remaining reaction flywheels, failing to automatically optimize output when reaction flywheels are insufficient.

[0004] Therefore, there is an urgent need for a method that can detect the saturation state of reaction flywheels in real time and dynamically allocate them, so as to achieve efficient utilization of redundant resources of multiple reaction flywheels and still output the maximum available torque when reaction flywheels are insufficient, thereby improving the reliability of spacecraft attitude control system and mission completion rate. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, the technical problem to be solved by this invention is to provide a redundant reaction flywheel torque adaptive allocation method based on saturation control. This method can improve the timeliness of reaction flywheel saturation detection and switching, avoid insufficient attitude control torque, rationally allocate the workload of redundant reaction flywheels, extend the overall life of the system and improve reliability, dynamically optimize torque allocation when reaction flywheels are insufficient, ensure the maximum available torque output, and maintain control continuity.

[0006] The technical solution of this invention is: a redundant reaction flywheel torque adaptive distribution method based on saturation control, which includes the following steps:

[0007] (1) Initially, set the saturation threshold and reset threshold of each reaction flywheel according to its own performance parameters;

[0008] (2) Activate the redundant attitude torque control mode of the reaction flywheel;

[0009] (3) Detect the attitude error and angular velocity error of the aircraft, and use the proportional-integral-derivative (PID) controller to calculate the desired torque for attitude adjustment;

[0010] (4) Detect the rotational speed of each reaction flywheel;

[0011] (5) Compare the rotational speed of each reaction flywheel with the saturation threshold and the reset threshold to select the usable reaction flywheel;

[0012] (6) Prioritize the reaction flywheels according to their operating status;

[0013] (7) Distribute torque according to the desired torque and the priority of the reaction flywheel. When it is a single reaction flywheel mode, execute step (8); when it is a multi-reaction flywheel mode, execute step (9); when it is a degraded mode, execute step (10).

[0014] (8) Activate the reaction flywheel with the highest priority to output the desired torque, and jump to step (11).

[0015] (9) Distribute the desired torque evenly among each reaction flywheel, and jump to step (11).

[0016] (10) All available reaction flywheels are powered at full capacity to the output;

[0017] (11) End.

[0018] The beneficial technical effects of the present invention are as follows:

[0019] 1. Monitor the flywheel saturation state in real time and dynamically distribute the control torque to ensure that each flywheel does not work in a saturated state for too long;

[0020] 2. It operates within the available range, thereby improving attitude control accuracy. It is applicable to various flywheel configurations and task requirements. Even if some flywheels are saturated or fail, the system can still maintain attitude control function.

[0021] Another method for adaptive torque distribution of redundant reaction flywheels based on saturation control is also provided, which includes the following steps:

[0022] (I) Several reaction flywheels are configured on each of the three attitude axes of roll, pitch and yaw. The saturation state of the reaction flywheels is determined by the protection speed, and the available set of reaction flywheels is maintained in real time.

[0023] (II) After the proportional-integral-derivative controller (PID) outputs the axial control torque, it adaptively calculates the required number of reaction flywheels and allocates the torque based on the maximum torque of the single reaction flywheel and the number of available reaction flywheels. When the number of available flywheels is insufficient to meet the demand, it enters the degraded mode and outputs the maximum available torque, thereby ensuring the continuity and reliability of control. Attached Figure Description

[0024] Figure 1 A flowchart of a redundant reaction flywheel torque adaptive allocation method based on saturation control according to the present invention is shown. Detailed Implementation

[0025] like Figure 1 As shown, this adaptive torque distribution method for redundant reaction flywheels based on saturation control includes the following steps:

[0026] (1) Initially, set the saturation threshold and reset threshold of each reaction flywheel according to its own performance parameters;

[0027] (2) Activate the redundant attitude torque control mode of the reaction flywheel;

[0028] (3) Detect the attitude error and angular velocity error of the aircraft, and use the proportional-integral-derivative (PID) controller to calculate the desired torque for attitude adjustment;

[0029] (4) Detect the rotational speed of each reaction flywheel;

[0030] (5) Compare the rotational speed of each reaction flywheel with the saturation threshold and the reset threshold to select the usable reaction flywheel;

[0031] (6) Prioritize the reaction flywheels according to their operating status;

[0032] (7) Distribute torque according to the desired torque and the priority of the reaction flywheel. When it is a single reaction flywheel mode, execute step (8); when it is a multi-reaction flywheel mode, execute step (9); when it is a degraded mode, execute step (10).

[0033] (8) Activate the reaction flywheel with the highest priority to output the desired torque, and jump to step (11).

[0034] (9) Distribute the desired torque evenly among each reaction flywheel, and jump to step (11).

[0035] (10) All available reaction flywheels are powered at full capacity to the output;

[0036] (11) End.

[0037] The beneficial technical effects of the present invention are as follows:

[0038] 1. Monitor the flywheel saturation state in real time and dynamically distribute the control torque to ensure that each flywheel does not work in a saturated state for too long;

[0039] 2. It operates within the available range, thereby improving attitude control accuracy. It is applicable to various flywheel configurations and task requirements. Even if some flywheels are saturated or fail, the system can still maintain attitude control function.

[0040] Preferably, in step (1), several reaction flywheels are configured on each of the three attitude axes of roll, pitch, and yaw, with their geometric axes aligned with the control axes; assuming the required control torque for a single axis is... Maximum torque of a single reaction flywheel The number of the reaction flywheel on this shaft , i represents the speed of the i-th reaction flywheel. In step (1), the saturation threshold is set to... The reset threshold is set to For example, three reaction flywheels are configured on each of the roll, pitch, and yaw attitude axes, for a total of nine reaction flywheels. Their geometric axes are aligned with the control axes. The specifications of each reaction flywheel are: angular momentum 1.35 Nm, maximum torque 0.1 Nm, rated speed 6000 rpm, and protection speed 5500 rpm. Assume the required control torque for a single axis is... Maximum torque of a single reaction flywheel The three reaction flywheels on this shaft are numbered Rotation speed .

[0041] The following examples illustrate in detail how the desired axial moment is calculated using PID control. .

[0042] In an optional embodiment, a cascaded PID (dual-loop PID) controller is employed. The outer loop controller outputs a target angular velocity based on the angular error to achieve the target angle. The inner loop controller determines the torque required to achieve the target angular velocity given by the outer loop.

[0043] Detect its own angle information, compare it with the target angle information, and obtain the angle error. Angular error integral ;

[0044] The formula for calculating the outer loop-angle loop is: Target angular velocity = ; The ratio of the angle ring, Integral of the angle ring;

[0045] Detect its own angular velocity information, compare it with the target angular velocity information, and obtain the angular velocity error. Angular velocity error integral Angular velocity error differential ;

[0046] The calculation formula for the inner loop - angular velocity loop: ; The proportion of the angular velocity loop, Integral of the angular velocity loop.

[0047] In step (5), the saturation threshold Reset threshold All reaction flywheels are initially in a usable state. ;

[0048] like Flag position This indicates that the system is saturated and unavailable.

[0049] If the previous saturation was followed by a speed that is not greater than the reset threshold, i.e. , This indicates that the reset is available;

[0050] The available set of reaction flywheels is obtained as the available set S. .

[0051] Preferably, in step (6), the required quantity Actual available quantity ;

[0052] Selection strategy: Select the top option from S based on priority. Platform, forming a distribution set ;

[0053] Priority metrics:

[0054] momentum margin This means that the one with the greater margin will be given priority;

[0055] Based on temperature and power constraints, those with low temperature and low power consumption are given priority;

[0056] Those with fewer cumulative working hours will be given priority.

[0057] Preferably, in step (7), if and Then it enters single flywheel mode; in step (8), only the single flywheel mode is enabled. The highest priority unit is assigned the following value:

[0058] ;

[0059] In step (7), if and Then, it enters the multi-flywheel mode; in step (9), the desired torque is evenly distributed to the allocation set. In the flywheel, assign the following value:

[0060] .

[0061] Preferably, in step (7), if Then it enters the degraded mode; in step (10), all available reaction flywheels output full power in the same direction, and are assigned the following values:

[0062] .

[0063] Another method for adaptive torque distribution of redundant reaction flywheels based on saturation control is also provided, which includes the following steps:

[0064] (I) Several reaction flywheels are configured on each of the three attitude axes of roll, pitch and yaw. The saturation state of the reaction flywheels is determined by the protection speed, and the available set of reaction flywheels is maintained in real time.

[0065] (II) After the proportional-integral-derivative controller (PID) outputs the axial control torque, it adaptively calculates the required number of reaction flywheels and allocates the torque based on the maximum torque of the single reaction flywheel and the number of available reaction flywheels. When the number of available flywheels is insufficient to meet the demand, it enters the degraded mode and outputs the maximum available torque, thereby ensuring the continuity and reliability of control.

[0066] Preferably, in step (I), the saturation threshold is determined based on one of the following: the actual output torque of the flywheel, the motor drive current, the motor temperature, the flywheel angular acceleration, and the vibration level, or a combination of these parameters.

[0067] Preferably, in step (II), the torque distribution adopts sequential distribution, equal distribution strategy, minimum residual torque difference distribution, priority low-speed flywheel distribution, weighted distribution based on flywheel health status, or solves the optimal distribution through intelligent algorithms such as linear programming, genetic algorithm, and particle swarm optimization; reaction flywheel state balance control is added during the distribution process so that each reaction flywheel works in a relatively close speed range for a long time.

[0068] Preferably, in step (II), after the reaction flywheel of a certain axis is saturated, the torque is compensated by a magnetic torque generator, chemical thruster or micropulse thruster, in addition to being shared by another reaction flywheel on the same axis; or before the reaction flywheel of a certain axis is saturated, the required torque is reduced by changing the maneuver path through an attitude trajectory replanning algorithm.

[0069] Furthermore, the number of reaction flywheels per shaft can be 2 to 4, and the total number of reaction flywheels in the system can be 4, 6, 8, or other combinations. The reaction flywheels can be arranged in different ways (such as Cartesian arrangement, offset arrangement, or mounted on non-orthogonal shafts), and the method of this invention is applicable to all of them.

[0070] This invention can achieve the following functions:

[0071] 1. Improve the timeliness of reaction flywheel saturation detection and switching to avoid insufficient attitude control torque;

[0072] 2. Rationally allocate the workload of redundant reaction flywheels to extend the overall lifespan of the system and improve reliability;

[0073] 3. When the reaction flywheel is insufficient, dynamically optimize the torque distribution to ensure the maximum available torque output and maintain control continuity.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for adaptive torque distribution of redundant reaction flywheels based on saturation control, characterized in that: It includes the following steps: (1) Initially, set the saturation threshold and reset threshold of each reaction flywheel according to its own performance parameters; (2) Activate the redundant attitude torque control mode of the reaction flywheel; (3) Detect the angle error and angular velocity error of the aircraft, and use the proportional-integral-derivative (PID) controller to calculate the desired torque for attitude adjustment; (4) Detect the rotational speed of each reaction flywheel; (5) Compare the rotational speed of each reaction flywheel with the saturation threshold and the reset threshold to select the usable reaction flywheel; (6) Prioritize the reaction flywheels according to their operating status; (7) Distribute torque according to the desired torque and the priority of the reaction flywheel. When it is a single reaction flywheel mode, execute step (8); when it is a multi-reaction flywheel mode, execute step (9); when it is a degraded mode, execute step (10); if and Then it enters single flywheel mode; if and Then it enters multi-flywheel mode; if If so, it will enter downgrade mode; among them, For the required control torque of a single axis, This represents the maximum torque of a single reaction flywheel. For the required quantity, , This refers to the actual available quantity. (8) Activate the reaction flywheel with the highest priority to output the desired torque, and jump to step (11). (9) Distribute the desired torque evenly among each reaction flywheel, and jump to step (11). (10) All available reaction flywheels are powered at full capacity to the output; (11) End.

2. The adaptive torque distribution method for redundant reaction flywheel based on saturation control according to claim 1, characterized in that: In step (1), several reaction flywheels are configured on each of the three attitude axes: roll, pitch, and yaw, with their geometric axes aligned with the control axes; assuming the required control torque for a single axis is... Maximum torque of a single reaction flywheel The number of the reaction flywheel on this shaft , where i represents the speed of the i-th reaction flywheel. In step (1), the saturation threshold is set to... The reset threshold is set to .

3. The adaptive torque distribution method for redundant reaction flywheel based on saturation control according to claim 2, characterized in that: In step (3), the self-attitude information is detected and compared with the target attitude information to obtain the angle error. Angular velocity error ; All reaction flywheels are initially in an operational state. ; like Flag position This indicates that the system is saturated and unavailable. like Flag position This indicates that the reset is available; The available set of reaction flywheels is obtained as the available set S. .

4. The adaptive torque distribution method for redundant reaction flywheel based on saturation control according to claim 3, characterized in that: In step (6), the required quantity Actual available quantity ; Selection strategy: Select the top option from S based on priority. Platform, forming a distribution set ; Priority measure: momentum margin This means that the one with the greater margin will be given priority; Based on temperature and power constraints, those with low temperature and low power consumption are given priority; Those with fewer cumulative working hours will be given priority.

5. The adaptive torque distribution method for redundant reaction flywheel based on saturation control according to claim 4, characterized in that: In step (7), if and Then it enters single flywheel mode; in step (8), only the single flywheel mode is enabled. The highest priority unit is assigned the following value: ； In step (7), if and Then, it enters the multi-flywheel mode; in step (9), the desired torque is evenly distributed to the allocation set. In the flywheel, assign the following value: 。 6. The adaptive torque distribution method for redundant reaction flywheel based on saturation control according to claim 5, characterized in that: In step (7), if Then it enters the degraded mode; in step (10), all available reaction flywheels output full power in the same direction, and are assigned the following values: 。 7. A method for adaptive torque distribution of redundant reaction flywheels based on saturation control, characterized in that: It includes the following steps: (I) Several reaction flywheels are configured on each of the three attitude axes of roll, pitch and yaw. The saturation state of the reaction flywheels is determined by the protection speed, and the available set of reaction flywheels is maintained in real time. (II) After the proportional-integral-derivative controller (PID) outputs the axial control torque, it adaptively calculates the required number of reaction flywheels and distributes the torque based on the maximum torque of the single reaction flywheel and the number of available reaction flywheels. When the available quantity is insufficient to meet demand, it enters degrade mode and outputs the maximum available torque to ensure control continuity and reliability; if and Then it enters single flywheel mode; if and Then it enters multi-flywheel mode; if If so, it will enter downgrade mode; among them, For the required control torque of a single axis, This represents the maximum torque of a single reaction flywheel. For the required quantity, , This represents the actual available quantity; when in single-reaction flywheel mode, the highest priority reaction flywheel is activated to output the desired torque. In multi-reaction flywheel mode, the desired torque is distributed evenly among the reaction flywheels; in degraded mode, all available reaction flywheels are powered at full capacity to the output.

8. The adaptive torque distribution method for redundant reaction flywheel based on saturation control according to claim 7, characterized in that: In step (I), the saturation threshold is determined based on one of the following: the actual output torque of the flywheel, the motor drive current, the motor temperature, the flywheel angular acceleration, and the vibration level, or a combination of these parameters.

9. The adaptive torque distribution method for redundant reaction flywheel based on saturation control according to claim 8, characterized in that: In step (II), the torque distribution adopts sequential distribution, equal distribution strategy, minimum residual torque difference distribution, priority low-speed flywheel distribution, weighted distribution based on flywheel health status, or solves the optimal distribution through intelligent algorithms such as linear programming, genetic algorithm, and particle swarm optimization; during the distribution process, reaction flywheel state balance control is added so that each reaction flywheel works in a relatively close speed range for a long time.

10. The adaptive torque distribution method for redundant reaction flywheel based on saturation control according to claim 9, characterized in that: In step (II), after the reaction flywheel of a certain axis is saturated, the torque is shared by another reaction flywheel on the same axis, and the torque is compensated by a magnetic torque generator, a chemical thruster or a micro-pulse thruster; or before the reaction flywheel of a certain axis is saturated, the required torque is reduced by changing the maneuver path through an attitude trajectory replanning algorithm.

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