Satellite flywheel control method and system under frequent yaw maneuvering working condition

Abstract

The application discloses a kind of frequent yaw maneuvering condition under satellite flywheel control method and system, according to the reliability of flywheel system, at least four non-coplanar reaction wheels work simultaneously, the optimal configuration quantity of flywheel system is five reaction wheels, five reaction wheels are arranged in flywheel system using three orthogonal+two oblique installation mode, when any one reaction wheel fails, four non-coplanar reaction wheels work simultaneously can still guarantee the high reliability of satellite, solve the problem that traditional four reaction wheel scheme will lead to other three reaction wheels frequent zero speed when any one flywheel fails, make satellite attitude jitter, simultaneously also reduce the service life of flywheel, simultaneously, five reaction wheels adopt three orthogonal+two oblique installation scheme, most conducive to satellite integration, simultaneously three orthogonal installation is attached to satellite cabin wall, beneficial to flywheel heat dissipation, five reaction wheel configuration scheme guarantees the high reliability of satellite, prolongs service life, with higher use value and popularization value.

Description

Technical Field

[0001] This invention relates to the field of aerospace vehicle attitude control technology, specifically to a satellite flywheel control method and system under frequent yaw maneuvers. Background Technology

[0002] Traditional satellite and on-orbit spacecraft control strategies mostly employ a zero-momentum three-axis stabilized active wheel control scheme, utilizing magnetic torque converters as the primary flywheel unloading method, which is economical and energy-saving. To ensure a certain level of reliability, the three-axis wheel control flywheel configuration typically uses four flywheels. However, if one flywheel malfunctions during satellite operation, only the remaining three flywheels can be used for control, causing the flywheel speed to return to near zero. During maneuvers, this inevitably leads to frequent zero-crossing of the flywheels. After a certain number of zero-crossings, the accumulated heat causes lubrication abnormalities, damaging the flywheel bearings. This type of failure is relatively common in large flywheels in China; therefore, flywheel operation must avoid frequent zero-crossings.

[0003] Regarding the above issues, the public account is... CN114036678A The patent, titled "A Dynamic Adjustment and Life Extension Method for Satellite Control Based on Flywheel Unit Reliability Dynamics," addresses the degradation and failure problem of satellite attitude control systems under prolonged unattended operation and lack of maintenance. It establishes a stochastic degradation process model for the flywheel and, based on this model, builds a flywheel reliability assessment model. Then, it simultaneously integrates the satellite attitude dynamics equations, the flywheel degradation stochastic process model, and the flywheel reliability assessment model to establish an extended flywheel degradation model. An attitude-coupled dynamics model is proposed; finally, a dynamic adjustment strategy for the weighting coefficients corresponding to satellite attitude and flywheel degradation under the model predictive control framework is designed to achieve a trade-off between control performance and lifespan. The drawback of this method is that improving wheel control lifespan through algorithmic strategies inevitably sacrifices some control and maneuverability performance.

[0004] Public account is CN115817858A The patent is titled "Installation Method and Design Method of Three Orthogonal Oblique Mounting Configuration for Remote Sensing Satellite Flywheel Assembly". It adopts the traditional four-flywheel installation method and design method of three orthogonal + one oblique mounting configuration of flywheel assembly. It solves the problem of needing to provide a flywheel installation method to avoid the flywheel speed crossing zero during satellite imaging. The disadvantage of this method is that if one flywheel fails, it will cause the flywheel to cross zero. If the satellite moves frequently, the frequent crossing of zero will reduce the satellite's lifespan. Therefore, this solution is not suitable for long-life satellites that move frequently.

[0005] Therefore, for on-orbit spacecraft with a lifespan requirement of more than 5 years, if the spacecraft frequently maneuvers, the wheel control configuration strategy needs to be optimized. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a satellite flywheel control method and system under frequent yaw maneuvers, which adopts an orthogonal and oblique mounting configuration strategy to improve the reliability and service life of the spacecraft under frequent yaw maneuvers.

[0007] This invention is achieved through the following technical solution:

[0008] A satellite flywheel control method under frequent yaw maneuvers includes the following processes:

[0009] Based on the reliability of the flywheel system, the optimal number of reaction wheels in the flywheel system is determined when at least four non-coplanar reaction wheels are working simultaneously in each flywheel system.

[0010] By adopting a three-orthogonal + two-oblique arrangement, the arrangement position of each reaction wheel in the optimal configuration is determined;

[0011] A four-degree-of-freedom flywheel system was adopted, and the arrangement angles of the four reaction wheels, three orthogonally and one obliquely mounted, were determined.

[0012] Based on the optimal number of reaction wheels and the installation angle of the four reaction wheels, a structural matrix is ​​constructed for multiple types of four non-coplanar reaction wheels to work simultaneously. Based on the constructed structural matrix, the optimal triaxial angular momentum envelope average value is determined, and the installation angle of another obliquely mounted reaction wheel is obtained.

[0013] Preferably, the optimal number of reaction wheels is determined as follows:

[0014] The reliability of each flywheel system is compared with a set threshold. The flywheel system with the lowest number of reaction wheels and the highest reliability is selected as the optimal configuration.

[0015] Preferably, the reliability calculation method for the flywheel system is as follows:

[0016]

[0017] in, m The number of non-coplanar reaction wheels that work simultaneously. n This represents the number of reaction wheels in the flywheel system.

[0018] Preferably, the optimal configuration of the flywheel system is five reaction wheels.

[0019] Preferably, the arrangement angles of the four reaction wheels, three orthogonal and one oblique, are as follows:

[0020] X-axis reaction wheel: (0, 90°, 90°), Y-axis reaction wheel: (90°, 0, 90°), Z-axis reaction wheel: (90°, 90°, 0), and the installation angle of the oblique reaction wheel S1 is (-54.74°, 57.74°, -54.74°).

[0021] Preferably, a combination of multiple structural matrices with four non-coplanar reaction wheels working simultaneously is constructed, the average value of the triaxial angular momentum envelope of each structural matrix is ​​solved, the largest average value of the triaxial angular momentum envelope is taken as the optimal average value of the triaxial angular momentum envelope, and the installation angle of another obliquely mounted reaction wheel is determined based on the optimal average value of the triaxial angular momentum envelope.

[0022] Preferably, the expressions for the various structure matrices are as follows:

[0023]

[0024] Preferably, the installation angle of the other inclined reaction wheel is... , ;

[0025] in, The angle between the reaction wheel axis and the Z-axis. The angle between the projection of the axis onto the XOY plane and the X-axis.

[0026] A satellite flywheel system for frequent yaw maneuvers includes five reaction wheels, with at least four non-coplanar reaction wheels operating simultaneously. The five reaction wheels are arranged in the flywheel system in a three-orthogonal + two-oblique configuration.

[0027] Preferably, the installation angles of the five reaction wheels are as follows:

[0028] The X-axis reaction wheel is (0, 90°, 90°), the Y-axis reaction wheel is (90°, 0, 90°), and the Z-axis reaction wheel is (90°, 90°, 0). The installation angle of the obliquely mounted reaction wheel S1 is (-54.74°, 57.74°, -54.74°), and the installation angle of the obliquely mounted reaction wheel S2 is... , ;

[0029] in, The angle between the reaction wheel axis and the Z-axis. The angle between the projection of the axis onto the XOY plane and the X-axis.

[0030] Compared with the prior art, the present invention has the following beneficial technical effects:

[0031] This invention provides a satellite flywheel control method for frequent yaw maneuvers. Based on the reliability of the flywheel system, when at least four non-coplanar reaction wheels are working simultaneously, the optimal configuration for the flywheel system is five reaction wheels. These five reaction wheels are arranged in a three-orthogonal + two-oblique configuration. Even if any one reaction wheel fails, the simultaneous operation of the four non-coplanar reaction wheels still ensures high satellite reliability. This solves the problem of the traditional four-reaction-wheel scheme, where a flywheel failure leads to frequent zero-speed crossings of the other three reaction wheels, causing satellite attitude jitter and reducing flywheel lifespan. Furthermore, the three-orthogonal + two-oblique mounting configuration of the five reaction wheels is most conducive to satellite integration, and the three-orthogonal mounting close to the satellite bulkhead facilitates flywheel heat dissipation. The five-reaction-wheel configuration ensures high satellite reliability and a long lifespan. Attached Figure Description

[0032] Figure 1 This is a schematic diagram showing the installation angle of the reaction flywheel of the present invention;

[0033] Figure 2 This is a simulation diagram of the triaxial average envelope angular momentum of the other four flywheels in the satellite flywheel system of this invention when one flywheel fails. The diagram shows that the angular momentum envelope is optimal when a=30° and B=60°.

[0034] Figure 3 This is a schematic diagram of the structure of the five reaction flywheels of the present invention. Detailed Implementation

[0035] The present invention will now be described in further detail with reference to the accompanying drawings. These descriptions are intended to explain the invention and not to limit it.

[0036] A method for configuring a satellite flywheel under frequent yaw maneuvers includes the following steps:

[0037] Step 1: Determine the reliability of each flywheel system. Each flywheel system includes multiple reaction wheels, and at least 4 non-coplanar reaction wheels work simultaneously. Compare the reliability of each flywheel system with the given threshold of the flywheel system. The flywheel system with the reliability greater than the threshold and the fewest number of reaction wheels is the optimal flywheel system, and its number of reaction wheels is the optimal configuration.

[0038] Specifically, the reliability of each reaction wheel is equal to The flywheel system must ensure n There are reaction wheels in m With two non-coplanar reaction wheels working simultaneously, the reliability index of the flywheel system... It can be represented as:

[0039]

[0040] To achieve three-axis zero-momentum control for a satellite, not only must all three principal axes of inertia possess attitude control capabilities, but the flywheel speed must also be guaranteed not to exceed zero. Therefore, at least four reaction wheels not on the same plane should operate simultaneously. Under these conditions, the reliability index of the wheel control system... It can be represented as:

[0041]

[0042] If only three non-coplanar reaction wheels are effective, the system can still be kept controllable, but the flywheel speed will frequently cross zero. On the one hand, due to attitude jitter, it will be difficult to guarantee the required attitude pointing accuracy; on the other hand, due to the mechanical limitations of the flywheel itself, the number of times the speed crosses zero within a single machine's lifespan is limited, thus causing unnecessary wear and tear on the flywheel's lifespan. In this case, the reliability index of the wheel control system will be affected. It can be represented as:

[0043]

[0044] Table 1 below compares the reliability of a flywheel system with 4 reaction wheels with that of a flywheel system with 5 reaction wheels.

[0045] Table 1

[0046]

[0047] The analysis results in Table 1 show that, under the premise of ensuring control indicators, to guarantee the continuous operation of at least four reaction wheels throughout the lifespan, when the reliability of a single reaction wheel is 0.97, the flywheel system composed of five reaction wheels has a higher reliability, reaching 0.9915, while the flywheel system composed of four reaction wheels can only reach 0.8853. Therefore, the five-reaction wheel configuration of this invention ensures the use of satellites with a lifespan of more than five years.

[0048] Step 2: Using a three-orthogonal + two-oblique arrangement scheme, design the installation positions of the five reaction wheels.

[0049] The reaction flywheel is a relatively high-power component in the attitude control unit. In order to meet the constraints of structural installation, and taking into account the use of attitude control and heat dissipation, as well as the overall satellite structural layout constraints and prioritizing the reliability of the flywheel system, a "three orthogonal + two oblique mounting" flywheel installation scheme was designed.

[0050] The four reaction wheels adopt a four-degree-of-freedom flywheel system arrangement, namely a three-orthogonal + one-oblique arrangement. The three reaction wheels are orthogonal to each other, and their axes are perpendicular to each other on the same plane. The axis of the fourth reaction wheel is at a certain angle to the axes of the other three reaction wheels.

[0051] The four-degree-of-freedom flywheel system is used to balance engine vibrations to reduce their impact on the fuselage. Three orthogonal reaction wheels balance vibrations in three directions (X, Y, and Z) respectively, while a fourth reaction wheel further balances vibrations in other directions. By adjusting the weight and moment of inertia of the four reaction wheels, effective balancing and regulation of vibrations in different directions can be achieved.

[0052] See Figure 1 The installation angles of the three orthogonal reaction wheels are X: (0, 90°, 90°), Y: (90°, 0, 90°), and Z: (90°, 90°, 0). The installation angle of the obliquely mounted reaction wheel S1 is (-54.74°, 57.74°, -54.74°). The angle between the axis of the obliquely mounted reaction wheel S2 and the Z-axis is... The projection of the axis onto the XOY plane makes an angle with the X-axis. The installation angle of the inclined reaction wheel S2 is determined according to the content of step 3.

[0053] The installation matrix of the five reaction wheels is as follows:

[0054]

[0055] Step 3: Based on the optimal number of reaction wheels and the installation angle of the four reaction wheels, construct various combination structures of four non-coplanar reaction wheels. Determine the optimal triaxial angular momentum envelope average value based on the constructed combination structures to obtain the installation scheme of the oblique reaction wheel S2.

[0056] Specifically, the design concept of the installation scheme for the inclined reaction wheel S2, as proven in step 1 above, is that five reaction wheels constitute the optimal configuration. Simultaneously, four non-coplanar reaction wheels need to operate. Assuming that any one reaction wheel malfunctions, the other four non-coplanar reaction wheels must provide the optimal triaxial angular momentum envelope average. Through permutations and combinations, various combination structure matrices of four non-coplanar reaction wheels operating simultaneously are constructed, and the triaxial angular momentum envelope average of each structure matrix is ​​calculated. The optimal triaxial angular momentum envelope average is obtained through comparison. The optimal triaxial angular momentum envelope average corresponds to... Angle and The angle is the installation angle of the reaction wheel S2.

[0057] Table 1 shows the differences ( , The average angular momentum of the three axes of the four-reaction wheel under the following condition

[0058]

[0059] As can be seen from Table 1, the installation angle of the inclined reaction wheel S2 is... , The optimal installation angle. Figure 2 This is a simulation diagram of the three-axis average envelope angular momentum of the other four flywheels in the satellite flywheel system of this invention when one flywheel fails. The diagram shows... =30°, =60° is the optimal angular momentum envelope.

[0060] See Figure 3 A satellite flywheel system for frequent yaw maneuvers includes five reaction wheels, with at least four non-coplanar reaction wheels operating simultaneously; the five reaction wheels are arranged in the flywheel system in a three-orthogonal + two-oblique configuration.

[0061] The installation angles of the five reaction wheels are as follows: the installation angles of the three orthogonal reaction wheels are: reaction wheel X: (0, 90°, 90°), reaction wheel Y: (90°, 0, 90°), reaction wheel Z: (90°, 90°, 0); the installation angle of the obliquely mounted reaction wheel S1 is (-54.74°, 57.74°, -54.74°); and the installation angle of the obliquely mounted reaction wheel S2 is... , .

[0062] This invention provides a satellite flywheel control method for frequent yaw maneuvers. Based on the reliability of the flywheel system, when at least four non-coplanar reaction wheels are working simultaneously, the optimal configuration for the flywheel system is five reaction wheels. These five reaction wheels are arranged in a three-orthogonal + two-oblique mounting configuration. This five-reaction-wheel configuration ensures high satellite reliability and long lifespan, avoiding the common problem of three reaction wheels frequently crossing zero speeds and causing satellite attitude jitter if one flywheel fails, thus reducing the flywheel's lifespan. Furthermore, installing too many obliquely mounted reaction wheels would require significant space on the satellite platform; therefore, the three-orthogonal + two-oblique mounting configuration is most conducive to satellite integration. Additionally, the three orthogonal mountings close to the satellite cabin wall facilitate flywheel heat dissipation.

[0063] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A satellite flywheel control method under frequent yaw maneuvering conditions, characterized in that, Includes the following processes: Based on the reliability of the flywheel system, determine the optimal number of reaction wheels in the flywheel system when at least four non-coplanar reaction wheels are working simultaneously in each flywheel system. By adopting a three-orthogonal + two-oblique arrangement, the arrangement position of each reaction wheel in the optimal configuration is determined; A four-degree-of-freedom flywheel system was adopted, and the arrangement angles of the four reaction wheels, three orthogonally and one obliquely mounted, were determined. Based on the optimal number of reaction wheels and the installation angle of the four reaction wheels, a structural matrix is ​​constructed for multiple types of four non-coplanar reaction wheels to work simultaneously. Based on the constructed structural matrix, the optimal triaxial angular momentum envelope average value is determined, and the installation angle of another obliquely mounted reaction wheel is obtained.

2. The satellite flywheel control method under frequent yaw maneuvers as described in claim 1, characterized in that, The optimal number of reaction wheels is determined as follows: The reliability of each flywheel system is compared with a set threshold. The flywheel system with the lowest number of reaction wheels and the highest reliability is selected as the optimal configuration.

3. The satellite flywheel control method under frequent yaw maneuvers according to claim 1, characterized in that, The reliability calculation method for the flywheel system is as follows: in, m The number of non-coplanar reaction wheels that work simultaneously. n The number of reaction wheels in the flywheel system. This is a reliability indicator for the reaction wheel.

4. The satellite flywheel control method under frequent yaw maneuvers according to claim 1, characterized in that, The optimal configuration for the flywheel system is five reaction wheels.

5. The satellite wheel control configuration method under frequent yaw maneuvering conditions according to claim 4, characterized in that, The arrangement angles of the four reaction wheels, consisting of three orthogonal and one oblique mounting, are as follows: X-axis reaction wheel: (0, 90°, 90°), Y-axis reaction wheel: (90°, 0, 90°), Z-axis reaction wheel: (90°, 90°, 0), and the installation angle of the oblique reaction wheel S1 is (-54.74°, 57.74°, -54.74°).

6. The satellite wheel control configuration method under frequent yaw maneuvering conditions according to claim 5, characterized in that, A variety of structural matrices with four non-coplanar reaction wheels working simultaneously are constructed by permutation and combination. The average value of the triaxial angular momentum envelope of each structural matrix is ​​solved. The maximum average value of the triaxial angular momentum envelope is taken as the optimal average value of the triaxial angular momentum envelope. The installation angle of another obliquely mounted reaction wheel is determined based on the optimal average value of the triaxial angular momentum envelope.

7. A satellite flywheel control method under frequent yaw maneuvers as described in claim 6, characterized in that, The expressions for the various structure matrices are as follows: in, and This refers to the installation angle of the reaction wheel.

8. A satellite flywheel control method under frequent yaw maneuvers as described in claim 6, characterized in that, The installation angle of the other inclined reaction wheel is , ; in, The angle between the reaction wheel axis and the Z-axis. The angle between the projection of the axis onto the XOY plane and the X-axis.

9. A satellite flywheel system for frequent yaw maneuvers, characterized in that, It includes five reaction wheels, with at least four non-coplanar reaction wheels working simultaneously. The five reaction wheels are arranged in a three-orthogonal + two-oblique configuration in the flywheel system.

10. A satellite flywheel system for frequent yaw maneuvers according to claim 9, characterized in that, The installation angles of the five reaction wheels are as follows: The five reaction wheels include an X-axis reaction wheel, a Y-axis reaction wheel, a Z-axis reaction wheel, an oblique reaction wheel S1, and an oblique reaction wheel S2; The X-axis reaction wheel is (0, 90°, 90°), the Y-axis reaction wheel is (90°, 0, 90°), and the Z-axis reaction wheel is (90°, 90°, 0). The installation angle of the obliquely mounted reaction wheel S1 is (-54.74°, 57.74°, -54.74°), and the installation angle of the obliquely mounted reaction wheel S2 is... , ; in, The angle between the reaction wheel axis and the Z-axis. The angle between the projection of the reaction wheel axis onto the XOY plane and the X-axis.

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