A self-centering clamping assembly and an on-orbit assembly method

Abstract

This invention discloses a self-centering clamping assembly and an on-orbit assembly method, relating to the field of space on-orbit assembly technology. It includes a first connector, with a first docking structure on one side for docking with an external component and a first connecting portion on the other side; a second connector, with a second docking structure on one side for docking with an external component and a second connecting portion on the other side; and a third connector, with a first docking portion and a second docking portion respectively on both sides. The first connecting portion can engage with the first docking portion, and the second connecting portion can engage with the second docking portion, so that the first and second connectors are configured to position and lock the third connector. The self-centering clamping assembly provided by this invention can solve the problem of difficult precise docking and assembly due to relative pose deviations during the on-orbit assembly of large flexible structural modules, ensuring efficient, reliable, and stable on-orbit assembly operations.

Description

Technical Field

[0001] This invention relates to the field of on-orbit assembly technology, and in particular to a self-centering clamping assembly and an on-orbit assembly method. Background Technology

[0002] Autonomous on-orbit assembly of space structures is a cutting-edge technology with profound significance and great challenges. Using a space robotic arm, basic units such as structural modules, components, or small spacecraft launched into orbit in one or more launches can be autonomously assembled into large or super-large spacecraft in sequence, which has advantages such as low construction, operation and maintenance costs and strong scalability.

[0003] Currently, significant breakthroughs have been achieved in the on-orbit assembly of rigid structural modules, playing a crucial role in fields such as space station construction. However, the larger-scale aerospace structures of the future are characterized by high flexibility, low fundamental frequency, and easy deformation, posing significant challenges to on-orbit assembly technology based on space robotic arms. First, limited by the measurement accuracy of space sensors and onboard computing resources, the measurement and positioning accuracy of the robotic arm's end effector is low, and its real-time performance is poor, resulting in significant relative pose deviations between the robotic arm and the gripped component during the grasping operation. Second, both the gripped component and the space robotic arm are in a microgravity environment with relative velocities and angular velocities; the relative pose deviation between the robotic arm's end effector and the gripped component changes over time, further increasing the difficulty of grasping. Third, during the grasping operation, contact and collisions between the robotic arm's end effector and the gripped component are inevitable. This can couple with the flexible vibrations of large flexible structural modules, causing dynamic deviations in the docking positions of the assembled structure. However, the assembly process of large flexible structural modules requires precise alignment of the two modules to be assembled at the docking mechanism, which has stringent requirements. Therefore, it is an urgent problem to solve to achieve relative pose error correction of large flexible structural modules during the gripping process in order to achieve precise assembly. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the aforementioned technical problems in the prior art. To this end, embodiments of the present invention provide a self-centering clamping assembly to address the problem of difficulty in precise docking and assembly caused by relative pose deviations during the on-orbit assembly of large flexible structural modules, ensuring efficient, reliable, and stable on-orbit assembly operations.

[0005] This invention also provides an on-orbit assembly method.

[0006] According to an embodiment of a first aspect of the present invention, a self-centering clamping assembly is provided, comprising a first connector having a first mating structure for mating with an external surface on one side and a first connecting portion on the other side; a second connector having a second mating structure for mating with an external surface on one side and a second connecting portion on the other side; and a third connector having a first mating portion and a second mating portion respectively on both sides, wherein the first connecting portion can engage with the first mating portion and the second connecting portion can engage with the second mating portion, such that the first connector and the second connector are configured to position and lock the third connector.

[0007] The aforementioned self-centering gripping assembly has at least the following advantages: the self-centering gripping assembly using the combination of the first connector, the second connector, and the third connector has advantages such as strong tolerance, high precision, and error correction. When using a dual-arm robotic system for on-orbit assembly, due to various reasons, there is often a certain relative pose error between the end effector of the robotic arm and the large flexible structure module. Using the self-centering gripping assembly of this application to grasp the clamped structure on-orbit, specifically, during gripping, the third connector is fixed to the clamped structure, and the first and second connectors are driven by the robotic arm, allowing them to move closer or further apart. When the first and second connectors move closer together and the first connecting part engages with the first mating part and the second connecting part engages with the second mating part, the six degrees of freedom of the third connector can be locked, and self-centering positioning can be achieved during the gripping process, thereby correcting the pose error of the large flexible structure module. This type of structure can effectively solve the problems of difficult docking, long time consumption, and large impact vibration during on-orbit assembly caused by factors such as the low frequency of large flexible structural modules and their susceptibility to spatial disturbances, ensuring the efficiency, accuracy and stability of the assembly process.

[0008] According to a first aspect embodiment of the present invention, when the first connector and the second connector are used together, the first connecting portion is disposed along a first direction and the second connecting portion is disposed along a second direction, wherein the first direction and the second direction intersect.

[0009] According to a first aspect of the present invention, the self-centering clamping assembly has the first direction and the second direction perpendicular.

[0010] According to the self-centering clamping assembly of the first aspect of the present invention, the radial cross section of the first connecting portion is an isosceles triangle or an isosceles trapezoid, and the first mating portion is a slot adapted to the first connecting portion.

[0011] According to the self-centering clamping assembly of the first aspect of the present invention, the radial cross-section of the second connecting portion is an isosceles triangle or an isosceles trapezoid, and the second mating portion is a notch that matches the second connecting portion.

[0012] According to the self-centering clamping assembly of the first aspect of the present invention, both the surface of the first connecting portion and the surface of the second mating portion are provided with a buffer structure.

[0013] According to a first aspect of the present invention, the self-centering clamping assembly includes a buffer structure comprising a plurality of steel balls arranged in an array, wherein a portion of the steel balls can extend beyond the surface of the first connecting portion or the surface of the second mating portion under the action of a spring.

[0014] According to a first aspect of the present invention, the self-centering clamping assembly includes a first positioning surface and a first through hole for a bolt to pass through, and the second docking structure includes a second positioning surface and a second through hole for a bolt to pass through.

[0015] According to the self-centering clamping assembly of the first aspect of the present invention, the end of the third connector is provided with a connecting groove for docking with the outside, and the third connector is also provided with a third through hole for a bolt to pass through, the third through hole extending through both sides of the third connector and communicating with the connecting groove.

[0016] According to an embodiment of a second aspect of the present invention, an on-orbit assembly method is provided, using the above-described self-centering clamping assembly, comprising the following steps:

[0017] S1. The end effectors of the first and second robotic arms are both equipped with the first connector and the second connector, and the first and second large flexible structure modules to be assembled are both fixed with the third connector.

[0018] S2. By trajectory planning, the change law of the joint angles of the first and second robotic arms during the on-orbit assembly process is obtained. The initial position joint angles of the first and second robotic arms are adjusted by the control algorithm to ensure that the first and second connecting parts at the end and the third connecting part are within the grasping range.

[0019] S3. Drive the first connector and the second connector to move closer to each other through the first robotic arm or the second robotic arm, so that the first connecting part is engaged with the first docking part and the second connecting part is engaged with the second docking part, so as to complete the positioning and locking of the third connector, thereby realizing the attitude correction of the first large flexible structure module or the second large flexible structure module.

[0020] S4. The first robotic arm and the second robotic arm execute assembly commands, causing the first large flexible structure module and the second large flexible structure module to move closer to each other, so as to complete the on-orbit assembly of the large flexible structure module through quick-connect couplings.

[0021] The above-mentioned on-orbit assembly method has at least the following beneficial effects: the above assembly scheme, combined with the practical application of the self-centering clamping component, can effectively solve the problems of difficult docking, long time consumption, and large impact vibration caused by factors such as the low frequency of large flexible structure modules and their susceptibility to spatial disturbances, thus ensuring the efficiency, accuracy and stability of the assembly process. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0023] Figure 1 This is a schematic diagram of the structure of the third connector in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the structure of the first connector in an embodiment of the present invention. Figure 1 ;

[0025] Figure 3 This is a schematic diagram of the structure of the second connector in an embodiment of the present invention. Figure 1 ;

[0026] Figure 4 This is a schematic diagram of the structure of the first connector in an embodiment of the present invention. Figure 2 ;

[0027] Figure 5 This is a schematic diagram of the structure of the second connector in an embodiment of the present invention. Figure 2 ;

[0028] Figure 6 This is a cross-sectional view of the third connector in an embodiment of the present invention;

[0029] Figure 7 This is a schematic diagram of the self-centering clamping component in use in an embodiment of the present invention. Figure 1 ;

[0030] Figure 8 This is a schematic diagram of the self-centering clamping component in use in an embodiment of the present invention. Figure 2 ;

[0031] Figure 9 This is a schematic diagram of the self-centering clamping component in use in an embodiment of the present invention. Figure 3 ;

[0032] Figure 10 This is a schematic diagram of the self-centering clamping component in use in an embodiment of the present invention. Figure 4 . Detailed Implementation

[0033] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0034] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0035] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0036] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0037] Reference Figures 1 to 3 , combined Figure 7 As understood, the self-centering clamping assembly provided in this application includes a first connector 200, a second connector 300, and a third connector 100. The first connector 200 has a first docking structure for docking with the outside on one side and a first connecting portion 210 on the other side. The second connector 300 has a second docking structure for docking with the outside on one side and a second connecting portion 310 on the other side. The third connector 100 has a first docking portion 120 and a second docking portion 110 on both sides. The first connecting portion 210 can engage with the first docking portion 120, and the second connecting portion 310 can engage with the second docking portion 110, so that the first connector 200 and the second connector 300 are configured to position and lock the third connector 100.

[0038] Specifically, the self-centering clamping assembly using the combination of the first connector 200, the second connector 300, and the third connector 100 has advantages such as strong tolerance, high precision, and error correction. When using a dual-arm robotic system for on-orbit assembly, due to various reasons, there is often a certain relative pose error between the end effector of the robotic arm and the large flexible structural module. The self-centering gripping assembly of this application is used to perform on-orbit gripping of the gripped structure. Specifically, during gripping, the third connector 100 is fixed to the gripped structure, the first docking structure of the first connector 200 is docked and fixed to the end of one of the robotic arms, and the second docking structure of the second connector 300 is docked and fixed to the end of another robotic arm. This allows the first connector 200 and the second connector 300 to be driven by the robotic arms, enabling them to move closer or further apart. When the first connector 200 and the second connector 300 move closer together and the first connecting part 210 engages with the first docking part 120 and the second connecting part 310 engages with the second docking part 110, the six degrees of freedom of the third connector 100 can be locked, and self-centering positioning can be achieved during the gripping process, thereby completing the correction of the pose error of the large flexible structure module. This type of structure can effectively solve the problems of difficult docking, long time consumption, and large impact vibration during on-orbit assembly caused by factors such as the low frequency of large flexible structural modules and their susceptibility to spatial disturbances, ensuring the efficiency, accuracy and stability of the assembly process.

[0039] In a preferred embodiment, when the first connector 200 and the second connector 300 are used together, the first connecting portion 210 is arranged along the first direction, and the second connecting portion 310 is arranged along the second direction. The first and second directions intersect; it should be noted that this intersection refers to the projection lines of the first and second directions onto the same plane intersecting. Preferably, the first and second directions are perpendicular. Correspondingly, the first mating portion 110 and the second mating portion 120 on the third connector 100 also intersect, that is, the first mating portion 110 and the second mating portion 120 form a cross-shaped structure. The first connecting portion 210 and the second connecting portion 310 also form a cross-shaped structure. When the first connector 200, the third connector 300, and the third connector 100 are clamped together, they form a bidirectional cross-shaped positioning system for large flexible structural modules, thereby achieving self-centering correction during the clamping process and improving clamping accuracy.

[0040] In some embodiments, such as Figure 2 As shown, the radial cross-section of the first connecting part 210 is an isosceles triangle or an isosceles trapezoid, such as... Figure 1 As shown, the first docking part 120 is a slot that is adapted to the first connecting part 210.

[0041] like Figure 3As shown, the radial cross-section of the second connecting part 310 is an isosceles triangle or an isosceles trapezoid, and the second mating part 110 is a notch that matches the second connecting part 310. The triangular or trapezoidal cross-section of the slot, notch, first connecting part 210, and second connecting part 310 facilitates rapid docking and connection stability after docking. At the same time, it enables the self-centering clamping assembly of this application to have the characteristics of large tolerance and multi-angle assembly in different directions.

[0042] Furthermore, such as Figure 4 and Figure 5 As shown, both the surface of the first connecting portion 210 and the surface of the second docking portion 110 are provided with a buffer structure. The buffer structure includes a plurality of steel balls 211 arranged in an array. Parts of the steel balls 211 can extend beyond the surface of the first connecting portion 210 or the second docking portion 110 under the action of springs. During the insertion of the first connecting portion 210 and the second docking portion 110 into the first docking portion 120 and the second docking portion 110 respectively, the steel balls 211 on the surface of the first connecting portion 210 or the second docking portion 110 are compressed by external force. The steel balls 211 compress the springs disposed inside the first connecting portion 210 or the second docking portion 110, causing elastic expansion and contraction, thereby minimizing the impact vibration during contact and collision, which is beneficial to the stability of the docking process.

[0043] In other embodiments, the first docking structure includes a first positioning surface and a first through hole 220 for bolts to pass through, and the second docking structure includes a second positioning surface and a second through hole 320 for bolts to pass through. When the first connector 200 docks with the robotic arm, the first positioning surface fits against the positioning surface on the robotic arm, and then the two are connected together by bolts. Similarly, when the second connector 300 docks with the robotic arm, the second positioning surface fits against the positioning surface of the robotic arm, and then the two are connected together by bolts to complete the docking assembly.

[0044] In other embodiments, such as Figure 6 As shown, the end of the third connector 100 is provided with a connecting groove 130 for docking with the outside. The third connector 100 is also provided with a third through hole 140 for bolts to pass through. The third through hole 140 extends through both sides of the third connector 100 and connects to the connecting groove 130. When fixing the third connector 100 to the large flexible structure, the connecting groove 130 is used for positioning and limitation, and then the bolts are used to pass through the third through hole 140 to achieve locking.

[0045] in, Figure 7 and Figure 8This is an embodiment of a ground test for on-orbit assembly of a large flexible space structure module using a self-centering clamping assembly. The embodiment includes a first large flexible structure module 600, a second large flexible structure module 601, a first robotic arm 400, a second robotic arm 401, and an elastic rope 500 for simulating a microgravity environment. Both the first robotic arm 400 and the second robotic arm 401 are mounted on the same fixed base so that they can work collaboratively. Figure 9 As shown, the side of the first large flexible structure module 600 is equipped with a quick-connect connector 610 that mates with the second large flexible structure module 601, so that the first large flexible structure module 600 and the second large flexible structure module 601 can be quickly connected and assembled to achieve modular assembly.

[0046] Specifically, this application also provides an on-orbit assembly method for a large flexible structure module 600 using the aforementioned self-centering clamping assembly. The method involves first mounting the first large flexible structure module 600 and the second large flexible structure module 601 to an aluminum frame via elastic ropes 500. The horizontal and vertical alignment of the first and second large flexible structure modules 600 and 601 is then adjusted using an adjuster and a trolley assembly. Finally, the first robotic arm 400 and the second robotic arm 401 are mounted on a fixed base, with the center of the fixed base positioned between the first and second robotic arms 400 and 401. The method includes the following steps:

[0047] S1, such as Figure 7 As shown, the end effectors of the first robotic arm 400 and the second robotic arm 401 are both equipped with the first connector 200 and the second connector 300, and the first large flexible structure module 600 and the second large flexible structure module 601 to be assembled are both fixed with the third connector 100.

[0048] S2. By trajectory planning, the change law of the joint angle of the first robotic arm 400 and the second robotic arm 401 during the on-orbit assembly process is obtained. The initial position joint angle of the first robotic arm 400 and the second robotic arm 401 is adjusted by the control algorithm to ensure that the first connector 200 and the second connector 300 at the end are within the grasping range of the third connector 100.

[0049] S3, such as Figure 8As shown, the first connecting member 200 and the second connecting member 300 are driven to move closer together by the first robotic arm 400 or the second robotic arm 401, so that the first connecting part 210 engages with the first docking part 120 and the second connecting part 310 engages with the second docking part 110, thereby completing the positioning and locking of the third connecting member 100, and thus realizing the attitude correction of the first large flexible structure module 600 or the second large flexible structure module 601. Specifically, the first robotic arm 400 drives the first connecting member 200 and the second connecting member 300 to move closer together, so that the first robotic arm 400 clamps the first large flexible structure module 600 through the cooperation of the first connecting part 210, the first docking part 120 and the third connecting member 100. The second robotic arm 401 drives the first connecting member 200 and the second connecting member 300 to move closer together, so that the second robotic arm 401 clamps the second large flexible structure module 601 through the cooperation of the first connecting part 210, the first docking part 120 and the third connecting member 100. Structural module 601; wherein, the end-effector coordinate systems of the first robotic arm 400 and the second robotic arm 401 are parallel, and their relative positional relationship with the fixed base coordinate system can be obtained through a transformation matrix. Assuming that before the self-centering clamping assembly closes, the first large flexible structural module 600 or the second large flexible structural module 601 has a certain positional deviation X = 0.15mm in the X direction, the center coordinate system of the third connector 100 is not parallel. After the first connector 200, the second connector 300 and the third connector 100 are clamped and connected, the first large flexible structural module 600 or the second large flexible structural module 601 will be deflected. The center coordinate system of the third connector 100 coincides with the end-effector coordinate system of the robotic arm 400, and the correction of the relative pose error of the first large flexible structural module 600 or the second large flexible structural module 601 is completed (X = 0). At this time, the first large flexible structural module 600 and the second large flexible structural module 601 are coplanar and at the same horizontal vertical height.

[0050] S4, such as Figure 9 and Figure 10 The first robotic arm 400 and the second robotic arm 401 execute assembly instructions, driving the first large flexible structure module 600 and the second large flexible structure module 601 to move closer to each other, so as to complete the on-orbit assembly ground test of the large flexible structure module through the quick-connect joint 610.

[0051] The above assembly scheme, combined with the practical application of the self-centering clamping component, can effectively solve the problems of difficult docking, long time consumption, and large impact vibration during on-orbit assembly caused by factors such as the low frequency of large flexible structural modules and their susceptibility to spatial disturbances, thus ensuring the efficiency, accuracy, and stability of the assembly process.

[0052] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. An on-orbit assembly method, comprising a self-centering clamping assembly, the self-centering clamping assembly including... The first connector (200) has a first docking structure on one side for docking with the outside and a first connecting part (210) on the other side. The second connector (300) has a second mating structure on one side for mating with the outside, and a second connecting part (310) on the other side; and The third connector (100) has a first mating part (120) and a second mating part (110) on both sides respectively. The first connecting part (210) can be engaged with the first mating part (120), and the second connecting part (310) can be engaged with the second mating part (110), so that the first connector (200) and the second connector (300) are configured to position and lock the third connector (100). Its features are: Includes the following steps: S1. The end effectors of the first robotic arm (400) and the second robotic arm (401) are both equipped with the first connector (200) and the second connector (300). The first large flexible structure module (600) and the second large flexible structure module (601) to be assembled are both fixed with the third connector (100). S2. By trajectory planning, the change law of the joint angle of the first robotic arm (400) and the second robotic arm (401) during the on-orbit assembly process is obtained. The initial position joint angle of the first robotic arm (400) and the second robotic arm (401) is adjusted by the control algorithm to ensure that the first connector (200) and the second connector (300) at the end are within the grasping range of the third connector (100). S3. The first connecting member (200) and the second connecting member (300) are driven to move closer to each other by the first robotic arm (400) or the second robotic arm (401) so that the first connecting part (210) is engaged with the first docking part (120) and the second connecting part (310) is engaged with the second docking part (110) to complete the positioning and locking of the third connecting member (100), thereby realizing the attitude correction of the first large flexible structure module (600) or the second large flexible structure module (601); S4. The first robotic arm (400) and the second robotic arm (401) execute assembly instructions, driving the first large flexible structure module (600) and the second large flexible structure module (601) to move closer to each other, so as to complete the on-orbit assembly of the large flexible structure module through the quick-connect connector (610).

2. The on-orbit assembly method according to claim 1, characterized in that: When the first connector (200) and the second connector (300) are used together, the first connecting part (210) is arranged along a first direction and the second connecting part (310) is arranged along a second direction, wherein the first direction and the second direction intersect.

3. The on-orbit assembly method according to claim 2, characterized in that: The first direction and the second direction are perpendicular.

4. The on-orbit assembly method according to claim 1, characterized in that: The radial cross section of the first connecting part (210) is an isosceles triangle or an isosceles trapezoid, and the first mating part (120) is a slot adapted to the first connecting part (210).

5. The on-orbit assembly method according to claim 1, characterized in that: The radial cross section of the second connecting part (310) is an isosceles triangle or an isosceles trapezoid, and the second mating part (110) is a notch that matches the second connecting part (310).

6. The on-orbit assembly method according to claim 1, characterized in that: Both the surface of the first connecting part (210) and the surface of the second docking part (110) are provided with a buffer structure.

7. The on-orbit assembly method according to claim 6, characterized in that: The buffer structure includes a plurality of steel balls (211) arranged in an array. Parts of the steel balls (211) can extend out of the surface of the first connecting part (210) or the surface of the second docking part (110) under the action of the spring.

8. The on-orbit assembly method according to claim 1, characterized in that: The first docking structure includes a first positioning surface and a first through hole (220) for bolts to pass through, and the second docking structure includes a second positioning surface and a second through hole (320) for bolts to pass through.

9. The on-orbit assembly method according to claim 1, characterized in that: The end of the third connector (100) is provided with a connecting groove (130) for docking with the outside. The third connector (100) is also provided with a third through hole (140) for bolts to pass through. The third through hole (140) extends through both sides of the third connector (100) and connects to the connecting groove (130).

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