Affine transformation-based spacecraft on-orbit service maneuvering collision avoidance method and system

Abstract

The invention relates to a spacecraft on-orbit service maneuvering collision avoidance method and system based on affine transformation, and the method comprises the steps: carrying out the affine transformation of a collision avoidance ellipsoid through employing the affine transformation design of a three-dimensional collision avoidance region model and employing a translation-rotation-zooming-translation-rotation transformation sequence; a collision avoidance ellipsoid of a service spacecraft is converted into a ball, and the collision avoidance ellipsoid of a target spacecraft is kept to be still an ellipsoid model, and in an actual approaching maneuvering task, the sight angle constraint enabling the mass center of the target spacecraft to be located in the sight range of the service spacecraft is combined. By means of the method, the collision avoidance judgment condition of the two ellipsoids obtained after affine transformation becomes more simplified, and therefore under the condition that collision avoidance judgment is more accurate, the calculated amount of collision avoidance judgment is greatly reduced, the safety, operation precision and operation efficiency of spacecraft on-orbit service are effectively improved, and smooth proceeding of the on-orbit service is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of spacecraft maneuver control, and relates to a spacecraft on-orbit service maneuver collision avoidance method and system based on affine transformation. Background Art

[0002] On-Orbit Servicing (OOS) technology refers to the use of specific service spacecraft to repair, refuel, upgrade equipment, and adjust the orbit of target spacecraft in orbit. With the increase in the number of spacecraft and the complexity of missions, the importance of on-orbit servicing technology has become increasingly prominent. The maneuvers involved in on-orbit servicing are usually more complex, requiring precise control of the orbit and attitude of the service spacecraft in three-dimensional space to ensure that it can approach and operate the target spacecraft. During this process, the service spacecraft must perform multiple precise orbit and attitude adjustments to avoid collisions with the target spacecraft and other surrounding space objects.

[0003] However, the existing on-orbit service spacecraft collision avoidance technology is usually not designed specifically for close maneuvers between two spacecraft, and its collision avoidance judgment model is relatively rough. For close maneuvers within a few dozen meters of the service spacecraft and the target spacecraft, a more sophisticated collision avoidance judgment model needs to be designed to achieve more sophisticated collision avoidance judgment and control, so as to fully ensure the mission safety of on-orbit service during close maneuvers. Therefore, the existing on-orbit service spacecraft collision avoidance technology still has technical problems of insufficient safety and operation accuracy in actual close maneuvering applications. Summary of the invention

[0004] In response to the problems existing in the above-mentioned traditional methods, the present invention proposes a spacecraft on-orbit servicing maneuvering collision avoidance method based on affine transformation and a spacecraft on-orbit servicing maneuvering collision avoidance system based on affine transformation, which can effectively improve the safety and operational accuracy of spacecraft on-orbit servicing and ensure the smooth progress of space missions.

[0005] In order to achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0006] On the one hand, a method for avoiding collision of spacecraft on-orbit servicing maneuvers based on affine transformation is provided, comprising the steps of:

[0007] Obtain the position parameters of the service spacecraft and the target spacecraft obtained in the current sampling; the position parameters include the coordinates of the service spacecraft and the coordinates of the target spacecraft;

[0008] According to the position parameters and the size parameters of the service spacecraft and the target spacecraft, a collision avoidance ellipsoid of the service spacecraft and a collision avoidance ellipsoid of the target spacecraft are respectively constructed in the three-dimensional body coordinate system;

[0009] Performing affine transformation on the collision avoidance ellipsoids of the service spacecraft and the target spacecraft respectively, to obtain a collision avoidance sphere of the service spacecraft in the target spacecraft body coordinate system, and a collision avoidance ellipsoid of the target spacecraft whose center is located at the origin of the target spacecraft body coordinate system;

[0010] According to the collision avoidance sphere of the service spacecraft and the collision avoidance ellipsoid of the target spacecraft in the target spacecraft body coordinate system, collision avoidance discrimination is performed using the collision avoidance discrimination conditions of the service spacecraft and the target spacecraft;

[0011] The service spacecraft is subjected to collision avoidance control based on the result of collision avoidance judgment.

[0012] On the other hand, a spacecraft on-orbit service maneuver collision avoidance system based on affine transformation is also provided, comprising:

[0013] A data sampling module is used to obtain the position parameters of the service spacecraft and the target spacecraft obtained by the current sampling; the position parameters include the coordinates of the service spacecraft and the coordinates of the target spacecraft;

[0014] An ellipsoid construction module, used to construct a collision avoidance ellipsoid of the service spacecraft and a collision avoidance ellipsoid of the target spacecraft in a three-dimensional body coordinate system according to position parameters and size parameters of the service spacecraft and the target spacecraft;

[0015] An affine transformation module is used to perform affine transformation on the collision avoidance ellipsoids of the service spacecraft and the target spacecraft respectively, so as to obtain a collision avoidance sphere of the service spacecraft in the target spacecraft body coordinate system and a collision avoidance ellipsoid of the target spacecraft whose center is located at the origin of the target spacecraft body coordinate system;

[0016] A collision discrimination module, for performing collision avoidance discrimination based on the collision avoidance sphere of the service spacecraft and the collision avoidance ellipsoid of the target spacecraft in the target spacecraft body coordinate system, and using collision avoidance discrimination conditions of the service spacecraft and the target spacecraft;

[0017] The collision avoidance control module is used to perform collision avoidance control on the service spacecraft according to the results of collision avoidance judgment.

[0018] One of the above technical solutions has the following advantages and beneficial effects:

[0019] The above-mentioned spacecraft on-orbit service maneuver collision avoidance method and system based on affine transformation adopts the affine transformation design of the three-dimensional collision avoidance region model, constructs the collision avoidance ellipsoid of the service spacecraft and the collision avoidance ellipsoid of the target spacecraft based on affine transformation in the three-dimensional body coordinate system, and based on the relationship between the relative posture of the two spacecraft and the rotational affine transformation, adopts the transformation sequence of translation-rotation-scaling-translation-rotation to perform the affine transformation of the collision avoidance ellipsoid, transforms the collision avoidance ellipsoid of the service spacecraft into a sphere and keeps the collision avoidance ellipsoid of the target spacecraft as an ellipsoid model. In the actual proximity maneuvering mission, it combines the line of sight angle constraint that makes the center of mass of the target spacecraft within the line of sight of the service spacecraft, so that the collision avoidance judgment condition between the two ellipsoids obtained after the affine transformation becomes simpler, thereby greatly reducing the calculation amount of collision avoidance judgment while ensuring that the collision avoidance judgment is more accurate, effectively improving the safety, operation accuracy and operation efficiency of the on-orbit service of the spacecraft under the proximity maneuvering condition, and ensuring the smooth progress of the on-orbit service. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 A schematic diagram of a flow chart of a method for avoiding collision during on-orbit servicing maneuvers of a spacecraft based on affine transformation in one embodiment;

[0022] Figure 2 A schematic diagram of modeling a spacecraft collision avoidance zone in a two-dimensional plane in one embodiment;

[0023] Figure 3 A schematic diagram of modeling a spacecraft collision avoidance zone in a three-dimensional plane in one embodiment;

[0024] Figure 4 The present invention is a schematic diagram of the module structure of a spacecraft on-orbit service maneuver collision avoidance system based on affine transformation in one embodiment. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0027] It should be noted that the reference to "embodiment" in this article means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The presentation of this phrase at various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It will be appreciated by those skilled in the art that the embodiments described herein may be combined with other embodiments. The term "and / or" used in the specification of the present invention and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0028] The following will describe the implementation of the present invention in detail with reference to the accompanying drawings in the embodiment diagram of the present invention.

[0029] Although affine transformation is a commonly used geometric transformation method in mathematics and computer graphics, it can describe operations such as translation, rotation, scaling and shearing of objects in space. However, the application of affine transformation to the close-proximity maneuvering control scenario of spacecraft in orbit service has limited research results. This paper studies the use of affine transformation to describe and calculate the orbit and attitude changes of spacecraft, so as to achieve accurate collision avoidance judgment and control of spacecraft close-proximity maneuvers.

[0030] In one embodiment, Figure 1 As shown, a method for avoiding collision of spacecraft on-orbit servicing maneuvers based on affine transformation is provided, which may include the following processing steps S12 to S20:

[0031] S12, obtaining the position parameters of the service spacecraft and the target spacecraft obtained by the current sampling; the position parameters include the coordinates of the service spacecraft and the coordinates of the target spacecraft.

[0032] S14, constructing a collision avoidance ellipsoid of the service spacecraft and a collision avoidance ellipsoid of the target spacecraft in a three-dimensional body coordinate system according to the position parameters and the size parameters of the service spacecraft and the target spacecraft respectively; the three-dimensional body coordinate system may include a body coordinate system with the center of mass coordinates of the service spacecraft as the origin and a body coordinate system with the center of mass coordinates of the target spacecraft as the origin. The size parameters may be inherent size data such as the length, width and height of the spacecraft body and its solar sail panels in the unfolded state, which may be read and used according to actual calculation needs.

[0033] S16, performing affine transformation on the collision avoidance ellipsoids of the service spacecraft and the target spacecraft respectively, to obtain a collision avoidance sphere of the service spacecraft in the target spacecraft body coordinate system, and a collision avoidance ellipsoid of the target spacecraft whose center is located at the origin of the target spacecraft body coordinate system.

[0034] S18, performing collision avoidance determination based on the collision avoidance sphere of the service spacecraft and the collision avoidance ellipsoid of the target spacecraft in the target spacecraft body coordinate system and utilizing collision avoidance determination conditions of the service spacecraft and the target spacecraft.

[0035] S20, performing collision avoidance control on the service spacecraft according to the result of the collision avoidance determination.

[0036] It can be understood that, assuming that the spacecraft collision avoidance zone modeling adopts the ellipsoid model, the expression formula of the ellipsoid model in the three-dimensional coordinate system of the two spacecraft is:

[0037]

[0038] Among them, x1, y1 and z1 represent the coordinates of the ellipsoid in the three-dimensional coordinate system where the target spacecraft is located, a1, b1 and c1 represent the major semiaxis, minor semiaxis and polar axis of the ellipsoid model where the target spacecraft is located, respectively; x2, y2 and z2 represent the coordinates of the ellipsoid in the three-dimensional coordinate system where the service spacecraft is located, a2, b2 and c2 represent the major semiaxis, minor semiaxis and polar axis of the ellipsoid model where the service spacecraft is located, respectively.

[0039] In the actual application of spacecraft collision avoidance zone modeling and collision avoidance judgment, the two coordinate systems need to be unified so as to perform modeling and analysis in one coordinate system. This requires the use of the offset and relative attitude of the center of mass of the two spacecraft.

[0040] In order to better understand the final collision avoidance judgment conditions of the spacecraft in the close maneuvering scenario, this embodiment will be explained in the order of two-dimensional modeling to three-dimensional modeling. Figure 2 As shown, it is a schematic diagram of modeling the spacecraft collision avoidance area in a two-dimensional plane, which includes the service spacecraft A2 and the target spacecraft A1. The origin of the coordinate system where the service spacecraft is located can be recorded as (x0, y0), and θ is the angle between the x2 axis of the coordinate system where the service spacecraft is located and the x1 axis of the coordinate system where the target spacecraft is located, which can be used to characterize the relative attitude of the service spacecraft with respect to the target spacecraft.

[0041] In order to facilitate intuitive display and understanding, modeling and analysis are performed in a two-dimensional plane. Figure 2 As shown in Figure 2, taking the body coordinate system of the target spacecraft as the reference, the collision avoidance area model of the target spacecraft can be expressed as:

[0042]

[0043] The above model is written in matrix form as:

[0044]

[0045] Among them, T represents the transpose, and S1 represents the collision area ellipse coefficient matrix of the target spacecraft:

[0046]

[0047] For the coordinates of a point in coordinate system 2 (i.e., the three-dimensional coordinate system where the service spacecraft is located), its expression in coordinate system 1 (i.e., the three-dimensional coordinate system where the target spacecraft is located) is:

[0048]

[0049] Among them, R 12 Represents the coordinate transformation matrix from coordinate system 2 to coordinate system 1:

[0050]

[0051] The collision avoidance ellipse model of the service spacecraft in coordinate system 2 is:

[0052]

[0053] Therefore, substituting equations (6) and (7) into equation (8), the collision avoidance ellipse model of the service spacecraft can be expressed in coordinate system 1 as:

[0054]

[0055] The available matrix can be expressed as:

[0056]

[0057] Among them, S2 represents the collision area ellipse coefficient matrix of the service spacecraft:

[0058]

[0059] In accordance with the need for attitude and track integration control after collision avoidance judgment, this embodiment uses the affine transformation technology. Affine transformation does not change the coordinate axes of the coordinate system, but only translates, rotates, and scales the graphics in the original coordinate system, which is fundamentally different from the coordinate changes caused by coordinate system transformation. Figure 1The service spacecraft in the affine transformation needs to go through the following process: translation-rotation-scaling-translation-rotation. The ultimate goal is to transform the collision avoidance ellipse of the service spacecraft into a circle while keeping the center of mass of the target spacecraft at its original position. At this time, the collision avoidance ellipse of the target spacecraft is correspondingly transformed into another ellipse. The orientation and size of the ellipse need to be calculated. The specific processing process can be as follows:

[0060] The first step is translation transformation: translate the center of the collision avoidance ellipse of the service spacecraft to the origin. The transformation matrix M1 at this time is:

[0061]

[0062] Then, the collision avoidance ellipse of the service spacecraft after the translation transformation is obtained as:

[0063]

[0064] The second step is rotation transformation, which transforms the orientation of the collision avoidance ellipse of the service spacecraft shown in equation (12) to the nominal orientation (e.g., the same orientation as A1). That is, it rotates -θ around the z1 axis (i.e., the direction perpendicular to the x1 axis and the y1 axis). At this time, the transformation matrix M2 is:

[0065]

[0066] Then, the collision avoidance ellipse of the service spacecraft after the rotation transformation is obtained as:

[0067]

[0068] The third step is scaling transformation: convert the collision avoidance ellipse of the service spacecraft shown in equation (14) into a circle. The transformation matrix M3 at this time is:

[0069]

[0070] Then, the collision avoidance circle of the service spacecraft after scaling transformation is obtained as:

[0071]

[0072] At this time, after the above series of transformations, the center of the original service spacecraft at the origin is transformed to:

[0073]

[0074] Step 4: Translation transformation: The center of the collision avoidance circle of the service spacecraft shown in equation (17) is translated. The translation coordinates are shown in equation (18). The transformation matrix M4 at this time is:

[0075]

[0076] Expanding equation (18), we can obtain that the center of the collision avoidance circle of the service spacecraft after the transformation is -(x * ,y * ), the collision avoidance circle of the service spacecraft after the above series of transformations is obtained as:

[0077]

[0078] After explaining the affine transformation processing of the collision avoidance ellipse of the service spacecraft, the transformation formula is obtained as follows:

[0079]

[0080] Based on the model formula (4) of the collision avoidance ellipse of the target spacecraft, the above affine transformation processing is applied to the collision avoidance ellipse of the target spacecraft, and the following can be obtained:

[0081]

[0082] in,

[0083] After the above processing, the size and direction of the ellipse determined by formula (21) can be further analyzed. Since formula (21) is equivalent to the following formula (22):

[0084]

[0085] Therefore, we can further define:

[0086]

[0087] According to formulas (22) and (23), the collision avoidance ellipse of the target spacecraft can be written as:

[0088]

[0089] The collision avoidance ellipse of the target spacecraft is centered on the origin of its coordinate system. After rotation and scaling, the size and direction of the major and minor semi-axes of the collision avoidance ellipse need to be further calculated and determined, so it needs to undergo another rotation transformation at this time.

[0090] Step 5: Rotation transformation: The above matrix M can be expressed as follows: M = blkdiag(M*, 0). blkdiag() is a function for creating a block diagonal matrix. By performing a diagonal transformation on the matrix M*, we can obtain:

[0091]

[0092] Among them, V* The matrix composed of eigenvectors is a unit orthogonal matrix, D * is a diagonal matrix. Define V = blkdiag(V*,1), D = blkdiag(D*,0), and combine formulas (24) and (25) to obtain:

[0093]

[0094] Therefore, after another rotation transformation:

[0095]

[0096] The collision avoidance ellipse of the target spacecraft can be transformed into:

[0097]

[0098] That is:

[0099]

[0100] Since the matrix D * is a diagonal matrix, and it can be determined that the collision avoidance ellipse of the target spacecraft is already in the nominal position.

[0101] Based on the service spacecraft collision avoidance circle shown in formula (19), the service spacecraft collision avoidance circle after another rotation transformation is:

[0102]

[0103] According to formula (30), the collision avoidance ellipse of the service spacecraft becomes a collision avoidance circle after the above series of transformations, and the center of the circle is Then, the collision avoidance criteria can be used directly to determine whether the two spacecraft will collide.

[0104] According to the collision avoidance ellipse shown in formula (29), since D * Let D be a diagonal matrix. * = diag(a,b), diag() is a function used to create a diagonal matrix or extract the diagonal elements of a matrix; assuming a>b, according to the sufficient conditions for avoiding collision between ellipse and circle, D can be defined # =diag(a+a / b,b+1), then the judgment condition for collision avoidance between the ellipse of the service spacecraft and the ellipse of the target spacecraft is:

[0105]

[0106] Affine transformation of the three-dimensional collision avoidance region model: When explaining the affine transformation processing of the three-dimensional collision avoidance region model, the overall understanding can refer to the affine transformation processing process of the two-dimensional collision avoidance region model mentioned above, that is, the transformation sequence of translation-rotation-scaling-translation-rotation is adopted. If the coordinate transformation matrix from the three-dimensional body coordinate system of the service spacecraft to the three-dimensional body coordinate system of the target spacecraft is R 12 , then the coordinate transformation matrix caused by the affine transformation is

[0107] According to the collision avoidance ellipsoid of the service spacecraft A2 and the target spacecraft A1, that is, formulas (1) and (2), it is assumed that the coordinates of the ellipsoid center of the service spacecraft A2 in the three-dimensional coordinate system of the target spacecraft A1 are (x0, y0, z0), and the relative posture of the service spacecraft A2 and the target spacecraft A1 can be expressed by the coordinate transformation matrix R 12 Then the spacecraft collision avoidance zone model in the three-dimensional plane can be expressed as Figure 3 shown.

[0108] The coordinates of a point (x2, y2, z2) on the service spacecraft on the target spacecraft can be expressed as:

[0109]

[0110] Then the collision avoidance ellipsoid of the service spacecraft in the target spacecraft body coordinate system is expressed as:

[0111]

[0112] Among them, the ellipsoid coefficient matrix S2 of the target spacecraft collision area is written as:

[0113]

[0114] The collision avoidance ellipsoid of the target spacecraft is expressed in the target spacecraft body coordinate system as follows:

[0115]

[0116] Among them, the ellipsoid coefficient matrix S1 of the service spacecraft collision area is written as:

[0117]

[0118] The affine transformation of translation-rotation-scaling-translation-rotation is used to perform affine transformation on the collision avoidance ellipsoids of the service spacecraft and the target spacecraft. The translation transformation matrix M1 translates the center of the collision avoidance ellipsoid of the service spacecraft to the origin of the target spacecraft body coordinate system, which can be written as:

[0119]

[0120] The rotation transformation matrix M2 transforms the collision avoidance ellipsoid of the service spacecraft to the nominal position of the target spacecraft body coordinate system, which can be written as:

[0121]

[0122] The scaling transformation matrix M3 transforms the collision avoidance ellipsoid of the service spacecraft into a sphere, which can be written as:

[0123]

[0124] At this point, after the above series of transformations, the center of the original target spacecraft at the origin is transformed to:

[0125]

[0126] Finally, another translation transformation M4 is performed to translate the center of the collision avoidance ellipsoid of the transformed target spacecraft to the origin:

[0127]

[0128] After the above series of affine transformations, the coordinate relationship between the transformed point and the point before the transformation in the three-dimensional coordinate system of the target spacecraft is:

[0129]

[0130] Substituting formula (42) into formula (33) and (35), and replacing (x1, y1, z1) with (x1′, y1′, z1′), we can obtain the equations of the collision avoidance ellipsoid of the service spacecraft and the collision avoidance ellipsoid of the target spacecraft after affine transformation in the three-dimensional coordinate system of the target spacecraft:

[0131]

[0132] Where S 1+ =blkdiag(S1,0). According to formula (43), the collision avoidance ellipsoid of the service spacecraft has been transformed into a sphere after affine transformation, and the coordinates of the center of the sphere in the three-dimensional coordinate system of the target spacecraft are (-x * , -y * , -z * ).

[0133] According to formula (44), the collision avoidance ellipsoid of the target spacecraft is still an ellipsoid after affine transformation, and the center position of the ellipsoid should be at the origin of the three-dimensional coordinate system of the target spacecraft; after scaling and rotation, the collision avoidance ellipsoid of the target spacecraft is in a non-nominal position.

[0134] Assumptions:

[0135]

[0136] According to formula (44), the collision avoidance ellipsoid of the target spacecraft is:

[0137]

[0138] Since the matrix M can be expressed in the form of M = blkdiag(M*,0), a diagonal transformation of M* can be obtained:

[0139]

[0140] Among them, V * The matrix composed of eigenvectors is a unit orthogonal matrix, D * is a diagonal matrix. Define V = blkdiag(V*,1), D = blkdiag(D*,0), and combine formulas (46) and (47) to obtain:

[0141]

[0142] Therefore, after another rotation transformation:

[0143]

[0144] The collision avoidance ellipsoid of the target spacecraft can be transformed into:

[0145]

[0146] That is:

[0147]

[0148] Since the matrix D * is a diagonal matrix. It can be seen that the collision avoidance ellipsoid of the target spacecraft is already in the nominal position. According to the collision avoidance sphere of the service spacecraft shown in formula (43), the collision avoidance sphere of the service spacecraft after another rotation transformation is obtained as:

[0149]

[0150] According to formula (52), the collision avoidance ellipsoid of the service spacecraft becomes a sphere after the above series of transformations, and the center of the sphere is Furthermore, the collision avoidance criteria can be used directly to determine whether two spacecraft will collide.

[0151] Further, according to the collision avoidance ellipsoid shown in formula (51), due to D *Let D be a diagonal matrix. * =diag(a,b,c), assuming a>b>c, based on the sufficient condition for collision avoidance between the ellipsoid and the sphere, define D # =diag(a+a / c,b+b / c,1), then the collision avoidance judgment condition between the service spacecraft and the target spacecraft corresponding to the current data sampling is:

[0152]

[0153] The collision avoidance judgment condition between the two ellipsoids is shown in formula (53). During the approach maneuver of the on-orbit service, the collision avoidance judgment condition of formula (53) can be directly used for collision avoidance judgment and control. By repeatedly executing the calculation and control processes such as collision avoidance ellipsoid construction, affine transformation, collision avoidance judgment and control after each position data sampling, the smooth progress of the on-orbit service can be fully ensured.

[0154] The above-mentioned spacecraft on-orbit service maneuver collision avoidance method based on affine transformation adopts the affine transformation design of the three-dimensional collision avoidance region model, constructs the collision avoidance ellipsoid of the service spacecraft and the collision avoidance ellipsoid of the target spacecraft based on affine transformation in the three-dimensional body coordinate system, and based on the relationship between the relative posture of the two spacecraft and the rotational affine transformation, adopts the transformation sequence of translation-rotation-scaling-translation-rotation to perform the affine transformation of the collision avoidance ellipsoid, transforms the collision avoidance ellipsoid of the service spacecraft into a sphere and keeps the collision avoidance ellipsoid of the target spacecraft as an ellipsoid model. In the actual proximity maneuvering mission, it combines the line of sight angle constraint that makes the center of mass of the target spacecraft within the line of sight of the service spacecraft, so that the collision avoidance judgment condition between the two ellipsoids obtained after the affine transformation becomes simpler, thereby greatly reducing the calculation amount of collision avoidance judgment while ensuring that the collision avoidance judgment is more accurate, effectively improving the safety, operation accuracy and operation efficiency of the on-orbit service of the spacecraft under the proximity maneuvering condition, and ensuring the smooth progress of the on-orbit service.

[0155] It should be understood that although the above process Figure 1 The steps in the flowchart are shown in the order indicated by the arrows, but the steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of the steps, and the steps can be executed in other orders. Figure 1 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequentially, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0156] In one embodiment, Figure 4 As shown, a spacecraft on-orbit service maneuver collision avoidance system 100 based on affine transformation is also provided, including a data sampling module 11, an ellipsoid construction module 13, an affine transformation module 15, a collision discrimination module 17 and a collision avoidance control module 19. Among them, the data sampling module 11 is used to obtain the position parameters of the service spacecraft and the target spacecraft obtained by the current sampling; the position parameters include the coordinates of the service spacecraft and the coordinates of the target spacecraft. The ellipsoid construction module 13 is used to construct the collision avoidance ellipsoid of the service spacecraft and the collision avoidance ellipsoid of the target spacecraft in the three-dimensional body coordinate system according to the position parameters and the size parameters of the service spacecraft and the target spacecraft. The affine transformation module 15 is used to perform affine transformation on the collision avoidance ellipsoids of the service spacecraft and the target spacecraft respectively, to obtain the collision avoidance sphere of the service spacecraft in the body coordinate system of the target spacecraft, and the collision avoidance ellipsoid of the target spacecraft whose center is located at the origin of the body coordinate system of the target spacecraft. The collision discrimination module 17 is used to perform collision avoidance discrimination based on the collision avoidance sphere of the service spacecraft and the collision avoidance ellipsoid of the target spacecraft in the target spacecraft body coordinate system, and to use the collision avoidance discrimination conditions of the service spacecraft and the target spacecraft. The collision avoidance control module 19 is used to perform collision avoidance control on the service spacecraft according to the result of the collision avoidance discrimination.

[0157] The above-mentioned spacecraft on-orbit service maneuver collision avoidance system 100 based on affine transformation adopts the affine transformation design of the three-dimensional collision avoidance area model, constructs the collision avoidance ellipsoid of the service spacecraft and the collision avoidance ellipsoid of the target spacecraft based on affine transformation in the three-dimensional body coordinate system, and based on the relationship between the relative posture of the two spacecraft and the rotational affine transformation, adopts the transformation sequence of translation-rotation-scaling-translation-rotation to perform the affine transformation of the collision avoidance ellipsoid, transforms the collision avoidance ellipsoid of the service spacecraft into a sphere and keeps the collision avoidance ellipsoid of the target spacecraft as an ellipsoid model. In the actual proximity maneuvering mission, it combines the line of sight angle constraint that makes the center of mass of the target spacecraft within the line of sight of the service spacecraft, so that the collision avoidance judgment condition between the two ellipsoids obtained after the affine transformation becomes simpler, thereby greatly reducing the calculation amount of collision avoidance judgment while ensuring that the collision avoidance judgment is more accurate, effectively improving the safety, operation accuracy and operation efficiency of on-orbit service in the case of spacecraft proximity maneuvering, and ensuring the smooth progress of on-orbit service.

[0158] In one embodiment, the collision avoidance judgment condition is:

[0159]

[0160] The coordinates of the center of the collision avoidance sphere of the service spacecraft in the target spacecraft body coordinate system are (-x* , -y * , -z * ), T represents transpose, V * The matrix composed of eigenvectors is a unit orthogonal matrix, D # =diag(a+a / c,b+b / c,1), is a diagonal matrix. diag() is an operation function used to create a diagonal matrix or extract the diagonal elements of a matrix. a, b and c represent the major semiaxis, minor semiaxis and polar axis of the ellipsoid where the target spacecraft is located, respectively.

[0161] It can be understood that for the specific explanation of the spacecraft on-orbit servicing maneuvering collision avoidance system 100 based on affine transformation, please refer to the corresponding explanation of the various embodiments of the spacecraft on-orbit servicing maneuvering collision avoidance method based on affine transformation in the above text, which will not be repeated here. The various modules in the above-mentioned spacecraft on-orbit servicing maneuvering collision avoidance system 100 based on affine transformation can be fully or partially implemented by software, hardware and their combination. The above-mentioned modules can be embedded in or independent of a device with data processing function in the form of hardware, or can be stored in the memory of the aforementioned device in the form of software, so that the processor can call and execute the operations corresponding to the above modules. The aforementioned device can be but not limited to various types of spacecraft measurement and control equipment already available in the art.

[0162] In one embodiment, a spacecraft control device is also provided, including a memory and a processor, the memory storing a computer program, and the processor implementing the following processing steps when executing the computer program: obtaining position parameters of the service spacecraft and the target spacecraft obtained by the current sampling; the position parameters include the coordinates of the service spacecraft and the coordinates of the target spacecraft; constructing a collision avoidance ellipsoid of the service spacecraft and a collision avoidance ellipsoid of the target spacecraft in a three-dimensional body coordinate system according to the position parameters, the size parameters of the service spacecraft and the target spacecraft respectively; performing affine transformation on the collision avoidance ellipsoids of the service spacecraft and the target spacecraft respectively to obtain a collision avoidance sphere of the service spacecraft in the body coordinate system of the target spacecraft, and a collision avoidance ellipsoid of the target spacecraft with its center at the origin of the body coordinate system of the target spacecraft; performing collision avoidance discrimination using collision avoidance discrimination conditions of the service spacecraft and the target spacecraft according to the collision avoidance sphere of the service spacecraft and the collision avoidance ellipsoid of the target spacecraft in the body coordinate system of the target spacecraft; and performing collision avoidance control on the service spacecraft according to the result of the collision avoidance discrimination.

[0163] It can be understood that the above-mentioned spacecraft control device, in addition to the memory and processor mentioned above, also includes other software and hardware components not listed in this specification. The specific components can be determined according to the model of the specific spacecraft collision avoidance control device in different application scenarios, and this specification will no longer list them in detail one by one.

[0164] In one embodiment, when the processor executes the computer program, it can also implement the steps or sub-steps added in each embodiment of the above-mentioned spacecraft on-orbit servicing maneuver collision avoidance method based on affine transformation.

[0165] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus dynamic random access memory (RambusDRAM, referred to as RDRAM) and interface dynamic random access memory (DRDRAM).

[0166] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0167] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and all of them belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A spacecraft on-orbit servicing maneuver collision avoidance method based on affine transformation, It is characterized in that Includes steps: Acquire the position parameters of the service spacecraft and the target spacecraft obtained by the current sampling; the position parameters include the coordinates of the service spacecraft and the coordinates of the target spacecraft; Constructing a collision avoidance ellipsoid of the service spacecraft and a collision avoidance ellipsoid of the target spacecraft in a three-dimensional body coordinate system according to the position parameters and the size parameters of the service spacecraft and the target spacecraft; Performing affine transformation on the collision avoidance ellipsoids of the service spacecraft and the target spacecraft respectively to obtain a collision avoidance sphere of the service spacecraft in the target spacecraft body coordinate system and a collision avoidance ellipsoid of the target spacecraft whose center is located at the origin of the target spacecraft body coordinate system; According to the collision avoidance sphere of the service spacecraft and the collision avoidance ellipsoid of the target spacecraft in the target spacecraft body coordinate system, collision avoidance discrimination is performed using collision avoidance discrimination conditions of the service spacecraft and the target spacecraft; The service spacecraft is subjected to collision avoidance control according to the result of the collision avoidance determination.

2. The spacecraft on-orbit service maneuver collision avoidance method based on affine transformation according to claim 1, It is characterized in that The collision avoidance judgment condition is: The coordinates of the center of the collision avoidance sphere of the service spacecraft in the target spacecraft body coordinate system are (-x * , -y * , -z * ), T represents transpose, V * The matrix composed of eigenvectors is a unit orthogonal matrix, D # =diag(a+a / c,b+b / c,1), is a diagonal matrix. diag() is an operation function used to create a diagonal matrix or extract the diagonal elements of a matrix. a, b and c represent the major semiaxis, minor semiaxis and polar axis of the ellipsoid where the target spacecraft is located, respectively.

3. A spacecraft on-orbit service maneuver collision avoidance system based on affine transformation, It is characterized in that include: A data sampling module is used to obtain the position parameters of the service spacecraft and the target spacecraft obtained in the current sampling; The position parameters include the coordinates of the service spacecraft and the coordinates of the target spacecraft; an ellipsoid construction module, configured to respectively construct a collision avoidance ellipsoid of the service spacecraft and a collision avoidance ellipsoid of the target spacecraft in a three-dimensional body coordinate system according to the position parameters and the size parameters of the service spacecraft and the target spacecraft; an affine transformation module, configured to perform affine transformation on the collision avoidance ellipsoids of the service spacecraft and the target spacecraft, respectively, to obtain a collision avoidance sphere of the service spacecraft in the target spacecraft body coordinate system, and a collision avoidance ellipsoid of the target spacecraft whose center is located at the origin of the target spacecraft body coordinate system; A collision determination module, configured to perform collision avoidance determination based on the collision avoidance sphere of the service spacecraft and the collision avoidance ellipsoid of the target spacecraft in the target spacecraft body coordinate system and using collision avoidance determination conditions of the service spacecraft and the target spacecraft; The collision avoidance control module is used to perform collision avoidance control on the service spacecraft according to the result of collision avoidance discrimination.

4. The spacecraft on-orbit service maneuver collision avoidance system based on affine transformation according to claim 3, It is characterized in that The collision avoidance judgment condition is: The coordinates of the center of the collision avoidance sphere of the service spacecraft in the target spacecraft body coordinate system are (-x * , -y * , -z * ), T represents transpose, V * The matrix composed of eigenvectors is a unit orthogonal matrix, D # =diag(a+a / c,b+b / c,1), is a diagonal matrix. diag() is an operation function used to create a diagonal matrix or extract the diagonal elements of a matrix. a, b and c represent the major semiaxis, minor semiaxis and polar axis of the ellipsoid where the target spacecraft is located, respectively.

Images