Satellite magnetic torquer control capability analysis method

Abstract

The invention discloses a satellite magnetic torquer control capability analysis method, and belongs to the technical field of satellite attitude and orbit control. The method comprises the following steps: firstly, acquiring triaxial magnetic field intensity data under a satellite body system; then, traversing all specified torque directions, for each specified torque direction, firstly calculating the average value of the maximum magnetic torques under different magnetic field intensities, and then calculating the corresponding magnetic torquer control capability; and finally, based on the control capability of the magnetic torquer in each specified torque direction, analyzing whether the magnetic torquer meets the control requirement or not. According to the method, the control capability of the magnetic torquer can be accurately obtained, and a decision basis is provided for configuration selection of the magnetic torquer.

Description

Technical Field

[0001] The invention relates to a satellite magnetic torquer control capability analysis method, belonging to the technical field of satellite attitude and orbit control. Background Art

[0002] Magnetic torquers are commonly used actuators for satellites. The magnetic torque of the magnetic torquer interacts with the geomagnetic field to generate magnetic torque that acts on the satellite to achieve attitude control of the satellite. The magnetic torquer does not consume fuel when working, but only consumes electrical energy. The magnetic torque generated as an external torque can change the angular momentum of the entire satellite. Therefore, magnetic torquers are often used to unload the angular momentum of the satellite. The torque that the magnetic torquer can provide is small and there is an error in the output torque. When used to directly control the satellite attitude, the magnetic torquer is only suitable for scenarios where the control torque demand is not large and the control accuracy requirement is not high.

[0003] The control capability of the magnetic torquer is an important factor in determining the selection and configuration of the satellite magnetic torquer. When analyzing the control capability of the magnetic torquer, the existing technology often roughly estimates it through the magnetic field modulus value, or analyzes the maximum control capability of the magnetic torquer on a certain axis of the body. These methods are not accurate enough in calculating the control capability, and do not consider the mutual influence between the three axes when the three axes are controlled simultaneously. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, a satellite magnetic torquer control capability analysis method is proposed, a specified torque direction is introduced, and the magnetic torquer control capability is calculated based on the maximum magnetic torque average value during the on-orbit magnetic field change.

[0005] The technical solution of the present invention is:

[0006] A satellite magnetic torquer control capability analysis method, comprising:

[0007] Obtain the three-axis magnetic field intensity data of the satellite system;

[0008] Traverse all specified torque directions, and for each specified torque direction, first calculate the average value of the maximum magnetic torque under different magnetic field strengths, and then calculate the corresponding magnetic torquer control capability;

[0009] Based on the control capability of the magnetic torquer in each specified torque direction, analyze whether the magnetic torquer meets the control requirements.

[0010] Furthermore, for each specified torque direction, the average value of the maximum magnetic torque is calculated as follows:

[0011] Calculate the magnetic moment m:

[0012]

[0013] Where B is the magnetic field strength in this system, t0 is the specified moment direction;

[0014] The maximum magnetic moment T is:

[0015] T=km×B

[0016]

[0017] Among them, M limx 、M limy 、M limz They are the three-axis magnetic moment limits, which are determined by the configuration of the magnetic torquer;

[0018] For multiple magnetic field intensities B, multiple maximum magnetic moments T are calculated respectively, and the average value of the maximum magnetic moments is calculated and recorded as T mean .

[0019] Furthermore, the method for calculating the control capability of the magnetic torquer is:

[0020] According to the average value of the maximum magnetic moment T mean The control capability of the magnetic torquer is described by the angular momentum that the magnetic torquer can provide within one orbital period, that is, the control capability of the magnetic torquer H m for:

[0021]

[0022] Among them, t orbit is the orbital period of the satellite.

[0023] Furthermore, the control capability of the magnetic torquer corresponding to each specified torque direction is analyzed using contour plots, specifically:

[0024] The spherical coordinates θ specifying the direction of the moment, The horizontal and vertical coordinates are the control capabilities of the magnetic torquer H in each specified torque direction. m The three components of are used as data to draw contour maps;

[0025] According to the disturbance torque conditions and magnetic control requirements of the satellite, the lower limit of the control capability of the magnetic torquer of the satellite's three axes is set, and the contour lines corresponding to the lower limit of the control capability and the area that meets the control capability requirements are marked on the contour map;

[0026] If there is a common part in the area where the three axes meet the control capability requirements, the magnetic torquer can meet the control requirements.

[0027] Furthermore, for different magnetic torquers, the control capability H of each magnetic torquer is marked on the same contour map. m The three components are compared to determine the advantages and disadvantages of each magnetic torquer.

[0028] Furthermore, the specified moment direction is expressed as:

[0029]

[0030] Among them, θ, are spherical coordinates that specify the direction of the moment.

[0031] Furthermore, we take θ∈[-90°,90°], Traverse all possible θ at set intervals, Achieve coverage of all specified torque directions.

[0032] Furthermore, the three-axis magnetic field strength data of the satellite system is obtained. The data should cover at least three orbital periods of the satellite, and at least 500 data points should be taken in each orbital period.

[0033] The advantages of the present invention compared with the prior art are:

[0034] The method proposed in the present invention improves the existing technology, proposes an algorithm for calculating the maximum magnetic torque in a specified torque direction, calculates the control capability of the magnetic torquer by obtaining the average value of the maximum magnetic torque of multiple tracks and traversing the specified torque direction, and vividly displays the control capability of the magnetic torquer by drawing a contour map. The method in the present invention can comprehensively reflect the three-axis control capability of the magnetic torquer, especially the mutual influence and mutual restriction of the three-axis control capability, and provide a decision-making basis for the configuration of the magnetic torquer. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0036] Figure 1 A schematic diagram of calculating the maximum magnetic moment in a specified direction according to an embodiment of the present invention;

[0037] Figure 2 This is a flow chart of a method for analyzing the control capability of a satellite magnetic torquer according to an embodiment of the present invention;

[0038] Figure 3 is a contour map of the control capability of the magnetic torquer under the first magnetic torque configuration of the embodiment of the present invention;

[0039] Figure 4 It is a contour map of the control capability of the magnetic torquer under the second magnetic torque configuration of an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0041] The present invention proposes a satellite magnetic torquer control capability analysis method, such as Figure 2 As shown, the following steps are included:

[0042] Step S1: Obtain the three-axis magnetic field strength data of the satellite system

[0043] The three-axis magnetic field strength data of the satellite system in the long-term operation state of the satellite in orbit is obtained through on-orbit measurement data or magnetic field theoretical formula calculation. To ensure the accuracy of subsequent calculation results, the data should cover at least three orbital periods of the satellite, and at least 500 data points should be taken in each orbital period.

[0044] Step S2: Determine the direction of the specified torque

[0045] Specify the torque direction t 0 It can be expressed as a unit vector in spherical coordinates:

[0046]

[0047] Select θ, is the spherical coordinate that specifies the direction of the moment. For the specific value of , please refer to step S4.

[0048] Step S3: Calculate the control capability of the magnetic torquer in the specified torque direction

[0049] Use the specified moment direction t determined in step S2 0 , the magnetic field strength B takes each set of data obtained in step S1 in turn, and calculates the maximum magnetic moment T:

[0050] The magnetic moment T is obtained by cross-producting the magnetic moment M and the magnetic field strength B, so the magnetic moment must be located in the plane β perpendicular to B. Figure 1 As shown, when the torque direction t is specified 0 When it is not perpendicular to B, the actual magnetic moment direction will be different from the specified moment direction. In this case, if the actual magnetic moment is along t 0 Projection t in the β plane 1 =(B×t 0 )×B, the error between the actual magnetic torque direction and the specified torque direction is the smallest. Among them, B×t 0It can be regarded as a magnetic moment. By scaling it proportionally according to the magnetic moment limit, the control capability of the magnetic torquer under the current specified torque direction and magnetic torquer configuration can be calculated. Therefore, when the magnetic field strength B of the system and the specified torque direction t are known, 0 Under the conditions, calculate in sequence:

[0051]

[0052] The maximum magnetic moment is:

[0053] T=km×B

[0054] Among them, M limx 、M limy 、M limz They are the three-axis magnetic torque limits, which are determined by the configuration of the magnetic torquer.

[0055] For each magnetic field strength B, the corresponding maximum magnetic moment T can be calculated. Step S1 obtains the magnetic field strength data including multiple magnetic field strengths B, and calculates multiple maximum magnetic moments T respectively, and calculates the average value of these maximum magnetic moments, which is recorded as T mean .

[0056] The control capability of the magnetic torquer is described by the angular momentum that the magnetic torquer can provide within one orbital period, that is, the control capability of the magnetic torquer is:

[0057]

[0058] Among them, t orbit is the orbital period of the satellite.

[0059] Step S4: traverse the specified torque direction

[0060] In step S2, the specified moment direction t is calculated. 0 When θ∈[-90°,90°], All possible directions of the specified torque can be covered. All possible θ, Repeat steps S2 to S3 to calculate the control capability H of the magnetic torquer with different specified torque directions. m .

[0061] Step S5: Draw contour map

[0062] After step S4, each group of θ, There are corresponding magnetic torquer control capabilities H m . θ, As the horizontal and vertical coordinates, and then H m The three components H mx , H my , H mzFor the data, draw a contour plot on the same graph.

[0063] Step S6: Data analysis

[0064] Analyze the data based on the contour map. According to the interference torque conditions and magnetic control requirements of the satellite, set the lower limit of the control capability of the satellite's three axes' magnetic torquer, and mark the contour lines corresponding to the lower limit of the control capability and the area that meets the control capability requirements on the contour map. If there is a common part in the area where the three axes meet the control capability requirements, the magnetic torquer can meet the control requirements, and the larger the common part, the greater the control capability margin. For different magnetic torquer configurations, set different three-axis magnetic torque limits for separate analysis to compare the advantages and disadvantages of each configuration.

[0065] The present invention will be further described below by specific embodiments:

[0066] Taking a satellite in a sun-synchronous orbit at an altitude of 700 km and working on the earth for a long time as an example, in step S1, the three-axis magnetic field strength of the satellite system is calculated at intervals of 10 seconds, and a total of 2000 sets of data are obtained; in step S2, according to θ, Determine the specified torque direction; in step S3, use 2000 sets of magnetic field strengths to calculate the maximum magnetic torque T and calculate the magnetic torquer control capability H m In step S4, repeat steps S2 to S3, and calculate different θ, The control capability of the magnetic torquer under the combination is H m ; Through step S5, a contour map is drawn.

[0067] Three-axis magnetic moment limit M limx =30A·m 2 、M limy =60A·m 2 、M limz =30A·m 2 The contour map drawn when Figure 3 As shown, the three-axis magnetic moment limit M limx =60A·m 2 、M limy =30A·m 2 、M limz =30A·m 2 The contour map drawn when Figure 4 As shown, the units of the horizontal and vertical axes of the two contour maps are degrees, and the units of the data in the figures are Nms / track.

[0068] If the satellite's requirements for the magnetotorque control capability are at least -2Nms / track for the roll axis, at least 6Nms / track for the pitch axis, and at least 2Nms / track for the yaw axis, then mark the corresponding contour lines in the contour map (indicated in Figure 3 and Figure 4 The area that meets the control capability requirements is represented by the bold line in Figure 3 and Figure 4 It can be seen that the areas where the three axes of the two magnetic torquer configurations meet the control capability requirements have common parts and can both meet the control requirements.

[0069] If the constant disturbance torque on the satellite pitch axis is much greater than that on the other two axes, the magnetic torquer needs to have stronger control capability on the pitch axis. Figure 3 and Figure 4 The corresponding two magnetic torquer configurations are attached. Figure 4 The magnetic torquer configuration is better. While ensuring the pitch axis magnetic torquer control capability of 10Nms / track, it can also ensure that the roll axis and yaw axis have a control capability of at least ±1Nms / track at the same time.

[0070] The above-described embodiments are only preferred specific implementations of the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A satellite magnetic torquer control capability analysis method, characterized in that: include: Obtain the three-axis magnetic field intensity data of the satellite system; Traverse all specified torque directions, and for each specified torque direction, first calculate the average value of the maximum magnetic torque under different magnetic field strengths, and then calculate the corresponding magnetic torquer control capability; Based on the control capability of the magnetic torquer in each specified torque direction, analyze whether the magnetic torquer meets the control requirements.

2. The satellite magnetic torquer control capability analysis method according to claim 1, characterized in that: For each specified torque direction, calculate the average value of the maximum magnetic torque as follows: Calculate the magnetic moment m: Among them, B is the magnetic field strength in this system, t0 is the specified torque direction; The maximum magnetic moment T is: T=km×B Among them, M limx 、M limy 、M limz They are the three-axis magnetic moment limits, which are determined by the configuration of the magnetic torquer; For multiple magnetic field intensities B, multiple maximum magnetic moments T are calculated respectively, and the average value of the maximum magnetic moments is calculated and recorded as T mean .

3. The satellite magnetic torquer control capability analysis method according to claim 1, characterized in that: The method for calculating the control capability of the magnetic torquer is: According to the average value of the maximum magnetic moment T mean The control capability of the magnetic torquer is described by the angular momentum that the magnetic torquer can provide within one orbital period, that is, the control capability of the magnetic torquer H m for: Among them, t orbit is the orbital period of the satellite.

4. The satellite magnetic torquer control capability analysis method according to claim 1, characterized in that: The control capability of the magnetic torquer corresponding to each specified torque direction is analyzed using contour plots, specifically: The spherical coordinates θ specifying the direction of the moment, The horizontal and vertical coordinates are the control capabilities of the magnetic torquer H in each specified torque direction. m The three components of are used as data to draw contour maps; According to the disturbance torque conditions and magnetic control requirements of the satellite, the lower limit of the control capability of the magnetic torquer of the satellite's three axes is set, and the contour lines corresponding to the lower limit of the control capability and the area that meets the control capability requirements are marked on the contour map; If there is a common part in the area where the three axes meet the control capability requirements, the magnetic torquer can meet the control requirements.

5. The satellite magnetic torquer control capability analysis method according to claim 4, characterized in that: For different magnetic torquers, the control capability H of each magnetic torquer is marked on the same contour map. m The three components are compared to determine the advantages and disadvantages of each magnetic torquer.

6. The satellite magnetic torquer control capability analysis method according to claim 1, characterized in that: The specified moment direction is expressed as: Among them, θ, are spherical coordinates that specify the direction of the moment.

7. The satellite magnetic torquer control capability analysis method according to claim 6, characterized in that: Take θ∈[-90°,90°], Traverse all possible θ at set intervals, Achieve coverage of all specified torque directions.

8. The satellite magnetic torquer control capability analysis method according to claim 1, characterized in that: The three-axis magnetic field strength data of the satellite system shall be obtained. The data shall cover at least three orbital periods of the satellite, and at least 500 data points shall be taken in each orbital period.

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