A test device and method for quantifying uncertainty in a large flexible module assembly process

Abstract

This invention discloses an experimental apparatus and method for quantifying the uncertainty of the assembly process of a large flexible module. The apparatus includes a large flexible module, a free-boundary suspension system, a non-contact motion capture system, and a disassembly / removal robotic arm. The large flexible module is the test object. The free-boundary suspension system provides boundary conditions for the free movement of the large flexible module, featuring adjustable static position and attitude, and dynamic free boundaries. The non-contact motion capture system is used to measure the position and attitude responses during the assembly process. The disassembly / removal robotic arm is used for assembling and disassembling multiple large flexible modules. The apparatus of this invention provides a ground-based experimental scheme for studying the assembly and disassembly process of large flexible modules in an on-orbit microgravity environment, and can repeat the assembly and disassembly process multiple times. The method of this invention can identify the dynamic characteristics of the structure using the vibration response generated by the large flexible module during the assembly process, and then quantify the uncertainty of the structural dynamic parameters using data from multiple assembly and disassembly processes.

Description

Technical Field

[0001] This invention relates to the field of environmental simulation testing technology and testing methods for aerospace assembly structures, specifically to a testing device and method for quantifying the uncertainty of the assembly process of large flexible modules. Background Technology

[0002] Large aerospace structures can be constructed through modular design, multiple rocket launches, and on-orbit assembly. However, unlike typical aerospace structures, large modular aerospace structures are lightweight and large in size, exhibiting low-frequency and high-frequency characteristics, making them susceptible to the effects of gravity during ground testing. Furthermore, it is difficult to ensure completely consistent contact and compression at the joints between modules during assembly, resulting in uncertainties in the overall dynamic parameters of the assembled structure. These uncertainties pose fundamental challenges to existing dynamic testing theories and methods based on deterministic models.

[0003] For ground-based simulation test devices for the on-orbit assembly of large flexible space modules, no similar technology has been found or reported. Furthermore, no similar domestic or international data has been collected on experimental methods for quantifying the uncertainties in dynamic parameters introduced during the assembly process. Summary of the Invention

[0004] To address the lack of suitable ground-based simulation test devices for the on-orbit assembly dynamics of large flexible aerospace modules and the absence of methods for quantifying the uncertainty of dynamic parameters in the prior art, this invention discloses a test device and method for quantifying the uncertainty of the assembly process of large flexible modules. The test device of this invention includes a large flexible module, a free-boundary suspension system, a non-contact motion capture system, and a disassembly / assembly robotic arm. The large flexible module, as the test object, is characterized by its large geometric dimensions, low natural frequency, and is equipped with quick-connect joints for docking with other large flexible modules. The free-boundary suspension system provides boundary conditions for the free movement of the large flexible module, featuring adjustable static position and attitude, and dynamic free boundaries. The non-contact motion capture system is used to measure the position and attitude response of the large flexible module during assembly. The disassembly / assembly robotic arm is used for assembling and disassembling multiple large flexible modules. The test method of this invention mainly uses the disassembly / assembly robotic arm to assemble and disassemble the module multiple times, during which working modal analysis is used to analyze multiple sets of response data measured by the non-contact motion capture system to quantify the uncertainty of dynamic parameters introduced by the assembly process. The apparatus of this invention provides a ground-based experimental scheme for studying the assembly and disassembly process of large flexible modules in a microgravity environment, and can repeat the assembly and disassembly process multiple times. The method of this invention can identify the dynamic characteristics of the structure by utilizing the vibration response generated by the large flexible module during the assembly process, and then quantify the uncertainty of the structural dynamic parameters from the data of multiple assembly and disassembly tests. This invention provides theoretical and technical support for quantitatively characterizing the assembly dynamic characteristics of large flexible modules.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention provides a large flexible module assembly test device, comprising a large flexible module (a first large flexible module, a second large flexible module, ..., an Nth large flexible module), a free boundary suspension system, a non-contact motion capture system, and a disassembly and assembly robotic arm;

[0007] The large flexible module is the test object, which is suspended on the free boundary suspension system and has the characteristics of large geometric size and low natural frequency.

[0008] The free boundary suspension system is fixed to the ground and is used to provide boundary conditions for the free movement of the large flexible module. It has the characteristics of adjustable static position and attitude and dynamic free boundary.

[0009] The non-contact motion capture system is fixed at a position suitable for observing the large flexible module, and is used to measure the position and attitude response of the large flexible module during the assembly process;

[0010] The assembly / disassembly robotic arm is freely movable and is used for assembling and disassembling multiple large flexible modules.

[0011] Furthermore, the side of the large flexible module in the large flexible module assembly test device is equipped with a quick-connect connector for docking with other large flexible modules. The quick-connect connector can realize the modular assembly or disassembly of the large flexible modules.

[0012] Furthermore, the number of the large flexible modules is N (N is equal to or greater than 2), which can be increased according to actual needs.

[0013] Furthermore, the free boundary suspension system in the large flexible module assembly test device includes: a support truss, a guide rail, a trolley assembly, a self-locking winder, and a soft elastic rope;

[0014] The guide rail is mounted on the support truss;

[0015] The trolley assembly is mounted on a guide rail and can slide freely along the guide rail. A rod structure with the self-locking winders at both ends is suspended below it by a steel wire rope.

[0016] The soft elastic rope is connected in series with the self-locking winder, and the large flexible module is suspended by two soft elastic ropes passing through the top two sides of the large flexible module.

[0017] Furthermore, the self-locking winder of the free boundary suspension system mainly includes a ratchet and a steel wire rope;

[0018] The wire rope is wound on the ratchet to adjust the length of the wire rope in the self-locking winder;

[0019] One end of the steel wire rope is connected in series with the soft elastic rope using a wire locking device.

[0020] Furthermore, in the large flexible module assembly test device, the free boundary suspension system adjusts the static position and attitude of the free boundary suspension system by rotating the ratchet to adjust the length of the steel wire rope in the self-locking winder.

[0021] Furthermore, the free boundary suspension system in the large flexible module assembly test device achieves the dynamic free boundary of the free boundary suspension system through guide rails and trolley components that can slide freely along the guide rails, as well as by using ultra-low stiffness soft elastic ropes in the vertical direction; the dynamic free boundary refers to the fact that the modal frequency of the rigid body motion of the large flexible module caused by the suspension of the soft elastic ropes does not exceed 1 / 5 of the fundamental frequency of the flexible vibration of the large flexible module.

[0022] Furthermore, the guide rails in the free boundary suspension system should be installed using a suitable method based on the assembly method of the large flexible module.

[0023] Furthermore, the non-contact motion capture system in the large flexible module assembly test device measures the three-dimensional coordinates of reflective markers pasted on the large flexible module using an infrared lens.

[0024] Furthermore, the disassembly and assembly robotic arm in the large flexible module assembly test device can also perform operations such as grabbing and transporting the large flexible module.

[0025] Secondly, the present invention provides an experimental method for quantifying the uncertainty in the assembly process of large flexible modules, comprising the following steps:

[0026] S1. Suspend the N large flexible modules on the free boundary suspension system using soft elastic ropes;

[0027] S2. Adjust the N large flexible modules to a horizontal position and to the same vertical height using the self-locking winder;

[0028] S3. The N large flexible modules are assembled using the assembly / disassembly robotic arm via quick-connect couplings;

[0029] S4. Utilize the non-contact motion capture system to measure the time-domain response data of vibrations generated during structural assembly and docking, and identify the modal parameters of the assembled structure;

[0030] S5. Use the aforementioned disassembly and assembly robotic arm to disassemble N large flexible modules via quick-connect couplings;

[0031] S6. Repeat steps S3 to S5 M times (M is equal to or greater than 3);

[0032] S7. Quantify the uncertainty of dynamic parameters brought about by the assembly process by measuring the data.

[0033] Furthermore, the test apparatus and the test method can be applied to coplanar assembly and non-coplanar assembly;

[0034] When performing coplanar assembly, the types of guide rails in the free boundary suspension system should include at least transverse guide rails;

[0035] When performing non-coplanar assembly, the guide rails in the free boundary suspension system should include at least transverse guide rails and longitudinal guide rails.

[0036] Furthermore, the specific steps of step S2 in the experimental method for quantifying the uncertainty of the large flexible module assembly process are as follows:

[0037] S2-1. Using a linear laser as an indicator, rotate the ratchet of the self-locking winder to adjust the length of the steel wire rope and adjust the N large flexible modules to a horizontal position;

[0038] S2-2. Using a linear laser as an indicator, rotate the ratchet of the self-locking winder to adjust the length of the steel wire rope and adjust the N large flexible modules to the same vertical height.

[0039] Furthermore, the specific steps of step S3 in the experimental method for quantifying the uncertainty of the large flexible module assembly process are as follows:

[0040] S3-1. Capture: Move the disassembly and assembly robotic arm to a suitable position in front of the large flexible module assembly test device, and use the non-contact motion capture system to measure the position of the two large flexible modules to be assembled, obtaining the relative distance between the two large flexible modules in the spatial rectangular coordinate system, and the position coordinates of the grippers of the two large flexible modules in the working coordinate system of the disassembly and assembly robotic arm; input the target position coordinates to the disassembly and assembly robotic arm to move it to the gripper position to form a capture; during capture, the gripper of the disassembly and assembly robotic arm is fixedly connected to the gripper, and it is ensured that the two do not slide relative to each other during the assembly test;

[0041] S3-2. Perception: Measure and calculate the position and orientation of the two large flexible modules to be assembled relative to the disassembly and assembly robot arm in the working coordinate system, and obtain the angle data of each joint of the disassembly and assembly robot arm;

[0042] S3-3. Trajectory Planning: Based on the data measured in S3-2 and the expected trajectories of the two large flexible modules to be assembled during the assembly process, the trajectory required for each joint of the robotic arm to be assembled and disassembled during the assembly process is planned. The expected trajectory of the two large flexible modules to be assembled during the assembly process should aim to minimize the displacement in the outward direction of the plate to ensure the smoothness of the assembly process.

[0043] S3-4. Assembly Implementation: Input the trajectory obtained from S3-3 into the disassembly and assembly robot arm. Under the condition that the entire system is in a stable posture and there is no obvious external disturbance, start the assembly process by gradually pulling the two large flexible modules to be assembled closer until they dock.

[0044] S3-5. Repeat steps S3-1 to S3-4 until N large flexible modules are assembled.

[0045] Furthermore, the specific steps of step S5 in the experimental method for quantifying the uncertainty of the large flexible module assembly process are as follows:

[0046] S5-1. Capture: Move the disassembly and assembly robotic arm to a suitable position in front of the large flexible module assembly test device. Use a non-contact motion capture system to measure the position of the grippers of the two large flexible modules to be disassembled, and obtain the position coordinates of the grippers in the working coordinate system of the disassembly and assembly robotic arm. Input the target position coordinates into the disassembly and assembly robotic arm to move it to the gripper position to form a capture. During capture, the gripper of the disassembly and assembly robotic arm is fixedly connected to the gripper, and it is ensured that the two do not slide relative to each other during the assembly test.

[0047] S5-2. Perception: Measure and calculate the position and orientation of the two large flexible modules to be disassembled relative to the disassembly and assembly robot arm in the working coordinate system of the disassembly and assembly robot arm, and obtain the angle data of each joint of the disassembly and assembly robot arm;

[0048] S5-3. Disassembly: Based on the data measured in S5-2, the two large flexible modules are disassembled by using the quick-connect joint between them.

[0049] S5-4. Repeat steps S5-1 to S5-3 until all N large flexible modules have been disassembled.

[0050] Furthermore, in step S4 of the experimental method for quantifying the uncertainty of the large flexible module assembly process, the data of the non-contact motion capture system is analyzed using the working mode analysis method.

[0051] Furthermore, step S4 of the experimental method for quantifying the uncertainty of the large flexible module assembly process is more specifically to process the data measured by the non-contact motion capture system using methods including but not limited to the temporal random subspace method.

[0052] Furthermore, step S7 of the experimental method for quantifying the uncertainty of the large flexible module assembly process is more specifically to calculate the uncertainty of the first n modal frequencies (n takes the value equal to or greater than 3) and modal damping ratio of the structure after the large flexible module assembly by repeating the measured data M times, thereby quantifying the uncertainty of the first n modal frequencies and modal damping ratio brought about by the assembly process.

[0053] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0054] The device of the present invention provides a ground test scheme for the study of the assembly and disassembly process of large flexible modules in a microgravity environment in orbit, and can repeat the assembly and disassembly process multiple times, solving the problem of the lack of ground simulation test device for the on-orbit assembly of large flexible aerospace modules.

[0055] The method of this invention can identify the dynamic characteristics of a structure by utilizing the vibration response generated by a large flexible module during the assembly process. Furthermore, it quantifies the uncertainty of structural dynamic parameters from data from multiple assembly and disassembly tests, solving the problem of the lack of experimental methods in existing technologies for quantifying the uncertainty of dynamic parameters introduced during the assembly process. This invention provides theoretical and technical support for quantitatively characterizing the assembly dynamics of large flexible modules. Attached Figure Description

[0056] Figure 1 This is a system diagram of the large flexible module assembly test device of the present invention;

[0057] Figure 2 This is a flowchart of the experimental method for quantifying the uncertainty in the assembly process of large flexible modules according to the present invention;

[0058] Figure 3 This is a schematic diagram of the unassembled module in an embodiment of the coplanar assembly of the present invention;

[0059] Figure 4 This is a schematic diagram showing the completed module assembly in an embodiment of the coplanar assembly of the present invention;

[0060] Figure 5 This is a schematic diagram of the unassembled module in a non-coplanar assembly embodiment of the present invention;

[0061] Figure 6 This is a schematic diagram showing the completed module assembly in a non-coplanar assembly embodiment of the present invention.

[0062] In the figure, there are: large flexible module 1, free boundary suspension system 2, non-contact motion capture system 3, disassembly and assembly robotic arm 4, first large flexible module 11, second large flexible module 12, support truss 21, guide rail 22, trolley assembly 23, self-locking winder 24, soft elastic rope 25, infrared lens 31, and reflective marker 32. Detailed Implementation

[0063] To enable those skilled in the art to better understand the technical solution of the present invention, the present application will be described in detail below with reference to the accompanying drawings and specific embodiments. The description in this part is only exemplary and explanatory, and should not be used to limit the scope of protection of the present application in any way.

[0064] Example 1

[0065] Please see Figure 1 The present invention provides a system diagram of a large flexible module assembly test device, which includes a large flexible module 1 (a first large flexible module 11, a second large flexible module 12, a third large flexible module 13, ..., an Nth large flexible module), a free boundary suspension system 2, a non-contact motion capture system 3, and a disassembly and assembly robotic arm 4.

[0066] The large flexible module 1 is the test object, which is suspended on the free boundary suspension system 2 and has the characteristics of large geometric size and low natural frequency.

[0067] The free boundary suspension system 2 is fixed on the ground and is used to provide boundary conditions for the free movement of the large flexible module 1. It has the characteristics of adjustable static position and attitude and dynamic free boundary. The free boundary suspension system 2 includes: support truss 21, guide rail 22, trolley assembly 23, self-locking winder 24, and soft elastic rope 25.

[0068] The non-contact motion capture system 3 is fixed at a position suitable for observing the large flexible module 1, and is used to measure the position and attitude response of the large flexible module during the assembly process;

[0069] The assembly / disassembly robotic arm 4 can move freely and is used for assembling and disassembling multiple large flexible modules 1.

[0070] Figure 2 The flowchart of the test method of the present invention includes the following steps:

[0071] S1. Suspend the N large flexible modules on the free boundary suspension system using the soft elastic ropes;

[0072] S2. Adjust the N large flexible modules to a horizontal position and to the same vertical height using the self-locking winder;

[0073] S3. The N large flexible modules are assembled using the assembly / disassembly robotic arm via quick-connect couplings;

[0074] S4. Utilize the non-contact motion capture system to measure the time-domain response data of vibrations generated during structural assembly and docking, and identify the modal parameters of the assembled structure;

[0075] S5. Use the aforementioned disassembly and assembly robotic arm to disassemble N large flexible modules via quick-connect couplings;

[0076] S6. Repeat steps S3 to S5 M times (M is equal to or greater than 3);

[0077] S7. Quantify the uncertainty of dynamic parameters brought about by the assembly process by measuring the data.

[0078] Example 2

[0079] Please see Figure 3 , Figure 4 , combined Figure 1 and Figure 2 ,

[0080] This embodiment is a coplanar assembly method. The large flexible module assembly test device in this embodiment includes a large flexible module 1, a free boundary suspension system 2, a non-contact motion capture system 3, and a disassembly and assembly robotic arm 4.

[0081] In this embodiment, there are two large flexible modules, including a first large flexible module 11 and a second large flexible module 12;

[0082] The first large flexible module 11 and the second large flexible module 12 are the test objects, which have the characteristics of large geometric size and low natural frequency, and are suspended on the free boundary suspension system 2.

[0083] The free boundary suspension system 2 is fixed on the ground and is used to provide boundary conditions for the free movement of the first large flexible module 11 and the second large flexible module 12. It has the characteristics of adjustable static position and attitude and dynamic free boundary.

[0084] The non-contact motion capture system 3 is used to measure the position and attitude response of the first large flexible module 11 and the second large flexible module 12 during the assembly process, and is fixed at a position suitable for observing the two large flexible modules;

[0085] The assembly / disassembly robotic arm 4 is freely movable and is used for assembling and disassembling the first large flexible module 11 and the second large flexible module 12. It can also capture and transport the large flexible modules. In this embodiment, the assembly / disassembly robotic arm is a mobile robotic arm.

[0086] The large flexible module assembly test device has a length of 2000mm, a width of 500mm, and a thickness of 2mm. The side is equipped with a quick-connect connector for docking with other large flexible modules. The quick-connect connector can realize the modular assembly or disassembly between the first large flexible module 11 and the second large flexible module 12.

[0087] The free boundary suspension system 2 in the large flexible module assembly test device includes: a support truss 21, a guide rail 22, a trolley assembly 23, a self-locking winder 24, and a soft elastic rope 25. The guide rail 22 is mounted on the support truss 21. The trolley assembly 23 is mounted on the guide rail 22 and can slide freely along the guide rail 22. A rod structure with the self-locking winder 24 at both ends is suspended below it by a steel wire rope. The soft elastic rope 25 is connected in series with the self-locking winder 24. Two soft elastic ropes 25 are used to suspend the large flexible module through the top sides of each large flexible module.

[0088] The assembly method in this embodiment is a coplanar assembly, therefore the types of guide rails 22 can include only horizontal guide rails, such as... Figure 3 and Figure 4 The guide rail 22 is shown in the figure.

[0089] The self-locking winder 24 of the free boundary suspension system mainly includes a ratchet and a steel wire rope; the steel wire rope is wound on the ratchet to adjust the length of the steel wire rope in the self-locking winder; one end of the steel wire rope is connected in series with the soft elastic rope 25 using a locking device.

[0090] The free boundary suspension system 2 in the large flexible module assembly test device adjusts the static position and attitude of the free boundary suspension system 2 by rotating the ratchet to adjust the length of the steel wire rope in the self-locking winder 24.

[0091] The free boundary suspension system 2 in the large flexible module assembly test device achieves the dynamic free boundary of the free boundary suspension system 2 through the guide rail 22 and the trolley assembly 23 that can slide freely along the guide rail, and by using the ultra-low stiffness soft elastic rope 25 in the vertical direction; the dynamic free boundary means that the rigid body motion mode frequency of the large flexible module 1 caused by the soft elastic rope suspension does not exceed 1 / 5 of the flexible vibration fundamental frequency of the large flexible module 1.

[0092] like Figure 3 and Figure 4 As shown, the non-contact motion capture system 3 in the large flexible module assembly test device measures the three-dimensional coordinates of reflective markers 32 affixed to the large flexible module using eight infrared lenses 31. Each large flexible module has six reflective markers affixed to it.

[0093] The experimental method of this embodiment includes the following steps:

[0094] S1. The first large flexible module 11 and the second large flexible module 12 are suspended on the free boundary suspension system 2 by soft elastic ropes 25;

[0095] S2. Adjust all the flexible modules to a horizontal position and to the same vertical height using the self-locking winder 24; the specific steps of step S2 are as follows:

[0096] S2-1. Using a linear laser as an indicator, rotate the ratchet of the self-locking winder 24 to adjust the length of the wire rope and adjust the first large flexible module 11 and the second large flexible module 12 to a horizontal position respectively.

[0097] S2-2. Using a linear laser as an indicator, rotate the ratchet of the self-locking winder 24 to adjust the length of the wire rope and adjust the first large flexible module 11 and the second large flexible module 12 to the same vertical height;

[0098] S3. Using the assembly / disassembly robotic arm 4, assemble the first large flexible module 11 and the second large flexible module 12 via quick-connect couplings; the specific steps of step S3 are as follows:

[0099] S3-1. Capture: Move the disassembly / assembly robotic arm 4 to a suitable position in front of the large flexible module assembly test device, and use the non-contact motion capture system 3 to measure the positions of the first large flexible module 11 and the second large flexible module 12, obtaining the positions of the first large flexible module 11 and the second large flexible module 12. Figure 3 and Figure 4 The relative distance d = 1000mm in the medium-space rectangular coordinate system, and the position coordinates of the grippers of the two large flexible modules in the working coordinate system of the disassembly and assembly robot arm; input the target position coordinates into the disassembly and assembly robot arm to move it to the gripper position to form a grasp; during the grasp, the gripper of the disassembly and assembly robot arm is fixedly connected to the gripper, and it is ensured that the two do not slide relative to each other during the assembly test;

[0100] S3-2. Perception: Measure and calculate the position and attitude of the first large flexible module 11 and the second large flexible module 12 relative to the disassembly and assembly robot arm in the working coordinate system, and obtain the angle data of each joint of the disassembly and assembly robot arm.

[0101] S3-3. Trajectory Planning: Based on the data measured in S3-2 and the expected trajectories of the first flexible module 11 and the second flexible module 12 during the assembly process, the trajectory required for each joint of the robotic arm to be assembled and disassembled during the assembly process is planned. The expected trajectory of the first flexible module 11 and the second flexible module 12 during the assembly process should aim to minimize the displacement in the outward direction of the plate to ensure the smoothness of the assembly process.

[0102] S3-4. Assembly Implementation: Input the trajectory obtained from S3-3 into the disassembly and assembly robotic arm. Begin the assembly process when the entire system is in stable posture and there are no significant external disturbances. Gradually pull the first large flexible module 11 and the second large flexible module 12 closer together until they are docked. Please refer to [link / reference] after assembly. Figure 4 .

[0103] S4. Utilize the non-contact motion capture system 3 to measure the time-domain response data of vibrations generated during structural assembly and docking, and identify the first three modes of the assembled structure; the specific steps of step S4 are as follows:

[0104] S4-1. Set the sampling rate of the non-contact motion capture system 3 to 90Hz, the acquisition duration to 60s, and the acquired data to be the time domain response data of 12 reflective markers. Use the working modal analysis method to analyze the data of the non-contact motion capture system 3.

[0105] S4-2. The data measured by the non-contact motion capture system 3 is processed using the temporal random subspace method to obtain the first three modes of the assembled structure;

[0106] S5. Using the assembly / disassembly robotic arm 4, the assembled first large flexible module 11 and second large flexible module 12 are disassembled via quick-connect couplings; the specific steps of step S5 are as follows:

[0107] S5-1. Capture: Move the disassembly and assembly robotic arm to a suitable position in front of the large flexible module assembly test device, and use a non-contact motion capture system to measure the position of the grippers of the first large flexible module 11 and the second large flexible module 12 to obtain the position coordinates of the grippers in the working coordinate system of the disassembly and assembly robotic arm; input the target position coordinates into the disassembly and assembly robotic arm to move it to the gripper position to form a capture; during capture, the gripper of the disassembly and assembly robotic arm is fixedly connected to the gripper, and it is ensured that the two do not slide relative to each other during the assembly test;

[0108] S5-2. Perception: Measure and calculate the position and attitude of the first large flexible module 11 and the second large flexible module 12 relative to the disassembly and assembly robot arm in the working coordinate system, and obtain the angle data of each joint of the disassembly and assembly robot arm.

[0109] S5-3. Disassembly: Based on the data measured in S5-2, the two large flexible modules are disassembled through the quick-connect joint between the first large flexible module 11 and the second large flexible module 12.

[0110] S6. Repeat steps S3 to S5 30 times;

[0111] S7. Calculate the uncertainty of the first three modal frequencies and modal damping ratio of the assembled structure by repeating the measurement 30 times, thereby quantifying the uncertainty of the first three modal frequencies and modal damping ratio brought about by the assembly process.

[0112] Example 3

[0113] Please see Figure 5 , Figure 6 , combined Figure 1 and Figure 2 ,

[0114] This embodiment uses a non-coplanar assembly method. The large flexible module assembly test device in this embodiment differs from that in Embodiment 2. The free boundary suspension system in this embodiment is equipped with transverse and longitudinal guide rails that meet the requirements for implementing non-coplanar assembly. Figure 5 , Figure 6 Guide rail 22 in the middle;

[0115] The type of disassembly and assembly robotic arm 4 used in this embodiment is different from that in Embodiment 1. The disassembly and assembly robotic arm 4 in this embodiment is a flying robotic arm. A marble air-floating platform is installed on the ground. The air supply of the flying robotic arm 4 lifts it up and suspends it on the marble air-floating platform through air suspension, thereby realizing operations such as assembly, disassembly, capture, and transportation of large flexible modules.

[0116] In sub-step S3-1, the non-contact motion capture system 3 is used to measure the positions of the first large flexible module 11 and the second large flexible module 12, obtaining the positions of the first large flexible module 11 and the second large flexible module 12. Figure 5 and Figure 6 In a medium-space rectangular coordinate system, the relative distance in the x-direction is dx = 1000 mm, and the relative distance in the y-direction is dy = 700 mm.

[0117] In the S3-3 sub-step, the relative distance between the first large flexible module 11 and the second large flexible module 12 in the out-of-plane direction is not 0. Therefore, during the trajectory planning process, the first large flexible module 11 and the second large flexible module 12 should have a certain deflection relative to their initial posture in order to reduce the vibration caused by the robotic arm during assembly and disassembly.

[0118] The other steps and parameter selections in this embodiment are the same as in Embodiment 2.

[0119] This invention discloses an experimental apparatus and method for quantifying the uncertainties in the assembly process of large flexible modules. The apparatus provides a ground-based experimental scheme for studying the assembly and disassembly processes of large flexible modules in an on-orbit microgravity environment, and can repeat the assembly and disassembly processes multiple times, addressing the current lack of ground-based simulation experimental apparatuses for the on-orbit assembly of large flexible aerospace modules. The method utilizes the vibration response generated by the large flexible module during assembly to identify the dynamic characteristics of the structure, and then quantifies the uncertainties of the structural dynamic parameters from data from multiple assembly and disassembly tests, solving the problem of the lack of experimental methods for quantifying the uncertainties of dynamic parameters brought about by the assembly process in existing technologies. This invention provides theoretical and technical support for quantitatively characterizing the assembly dynamics of large flexible modules.

[0120] The principles and implementation methods of the present invention have been described above through specific embodiments, and are only used to help understand the method and core ideas of the present invention. The two embodiments described are examples of the content of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements based on the present invention made without departing from the principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A large flexible module assembly test device, comprising a large flexible module, a free boundary suspension system, a non-contact motion capture system, and a disassembly and assembly robotic arm; The large flexible module is the test object and is suspended on the free boundary suspension system. The free boundary suspension system is fixed to the ground and is used to provide boundary conditions for the free movement of the large flexible module; The non-contact motion capture system is fixed at a position suitable for observing the large flexible module, and is used to measure the position and attitude response of the large flexible module during the assembly process; The assembly and disassembly robotic arm can move freely and is used for assembling and disassembling multiple large flexible modules; The number of the large flexible modules is N, among which, N is equal to or greater than 2; the side of the large flexible module is equipped with a quick-connect connector for docking with other large flexible modules, and the quick-connect connector can realize the modular assembly or disassembly of the large flexible modules. The assembly and disassembly robotic arm assembles N large flexible modules via quick-connect couplings; The non-contact motion capture system measures the time-domain response data of vibrations generated during structural assembly and docking, and uses working modal analysis to identify the modal parameters of the assembled structure. The uncertainty of dynamic parameters introduced by the assembly process is quantified by measuring the data.

2. The large flexible module assembly test device according to claim 1, characterized in that: The free boundary suspension system includes: a support truss, guide rails, a trolley assembly, a self-locking winder, and a soft elastic rope; The guide rail is mounted on the support truss, and the appropriate mounting method is selected for the guide rail according to the assembly method of the large flexible module; The trolley assembly is mounted on a guide rail and can slide freely along the guide rail. A rod structure with the self-locking winders at both ends is suspended below it by a steel wire rope. The soft elastic rope is connected in series with the self-locking winder, and the large flexible module is suspended by two soft elastic ropes passing through the top two sides of the large flexible module. The self-locking winder mainly includes a ratchet and a steel wire rope; The wire rope is wound on the ratchet to adjust the length of the wire rope in the self-locking winder; One end of the steel wire rope is connected in series with the soft elastic rope using a wire locking device.

3. The large flexible module assembly test device according to claim 2, characterized in that: The static position and attitude of the free boundary suspension system are adjusted by rotating the ratchet to adjust the length of the steel wire rope in the self-locking winder; the dynamic free boundary of the free boundary suspension system is achieved by using a guide rail and a trolley assembly that can slide freely along the guide rail, as well as by using an ultra-low stiffness soft elastic rope in the vertical direction; the dynamic free boundary refers to the fact that the modal frequency of the rigid body motion of the large flexible module caused by the suspension of the soft elastic rope does not exceed 1 / 5 of the fundamental frequency of the flexible vibration of the large flexible module; the non-contact motion capture system measures the three-dimensional coordinates of the reflective markers pasted on the large flexible module using an infrared lens.

4. A test method for quantifying the uncertainty of the large flexible module assembly process, utilizing the large flexible module assembly test apparatus described in claim 3, characterized in that, Includes the following steps: S1. Suspend the N large flexible modules on the free boundary suspension system using soft elastic ropes; S2. Adjust the N large flexible modules to a horizontal position and to the same vertical height using the self-locking winder; S3. The N large flexible modules are assembled using the assembly / disassembly robotic arm via quick-connect couplings; S4. Measure the time-domain response data of vibration generated by structural assembly and docking using the non-contact motion capture system, and identify the modal parameters of the assembled structure using the working modal analysis method; S5. Use the assembly / disassembly robotic arm to disassemble the assembled N large flexible modules via quick-connect couplings; S6. Repeat steps S3 to S5 M times, where M is equal to or greater than 3; S7. Quantify the uncertainty of dynamic parameters brought about by the assembly process by measuring the data.

5. The experimental method for quantifying the uncertainty of the assembly process of a large flexible module according to claim 4, characterized in that: The test method can be applied to both coplanar assembly and non-coplanar assembly. When performing coplanar assembly, the types of guide rails in the free boundary suspension system include at least transverse guide rails; When performing non-coplanar assembly, the guide rails in the free boundary suspension system include at least transverse guide rails and longitudinal guide rails.

6. The experimental method for quantifying the uncertainty of the assembly process of a large flexible module according to claim 4, characterized in that, The specific steps of step S2 are as follows: S2-1. Rotate the ratchet of the self-locking winder to adjust the length of the wire rope and adjust the N large flexible modules to a horizontal position; S2-2. Rotate the ratchet of the self-locking winder to adjust the length of the wire rope and adjust the N large flexible modules to the same vertical height.

7. The experimental method for quantifying the uncertainty of the assembly process of a large flexible module according to claim 4, characterized in that, The specific steps of step S3 are as follows: S3-1. Capture: Move the disassembly and assembly robotic arm to a suitable position in front of the large flexible module assembly test device, and use the non-contact motion capture system to measure the position of the two large flexible modules to be assembled, obtaining the relative distance between the two large flexible modules in the spatial rectangular coordinate system, and the position coordinates of the grippers of the two large flexible modules in the working coordinate system of the disassembly and assembly robotic arm; input the target position coordinates to the disassembly and assembly robotic arm to move it to the gripper position to form a capture; during capture, the gripper of the disassembly and assembly robotic arm is fixedly connected to the gripper, and it is ensured that the two do not slide relative to each other during the assembly test; S3-2. Perception: Measure and calculate the position and orientation of the two large flexible modules to be assembled relative to the disassembly and assembly robot arm in the working coordinate system, and obtain the angle data of each joint of the disassembly and assembly robot arm; S3-3. Trajectory Planning: Based on the data measured in S3-2 and the expected trajectories of the two large flexible modules to be assembled during the assembly process, the trajectory required for each joint of the robotic arm to be assembled and disassembled during the assembly process is planned. The expected trajectory of the two large flexible modules to be assembled during the assembly process should aim to minimize the displacement in the outward direction of the plate to ensure the smoothness of the assembly process. S3-4. Assembly Implementation: Input the trajectory obtained from S3-3 into the disassembly and assembly robot arm. Under the condition that the entire system is in a stable posture and there is no obvious external disturbance, start the assembly process by gradually pulling the two large flexible modules to be assembled closer until they dock. S3-5. Repeat steps S3-1 to S3-4 until N large flexible modules are assembled.

8. The experimental method for quantifying the uncertainty of the assembly process of a large flexible module according to claim 4, characterized in that, The specific steps of step S5 are as follows: S5-1. Capture: Move the disassembly and assembly robotic arm to a suitable position in front of the large flexible module assembly test device. Use a non-contact motion capture system to measure the position of the grippers of the two large flexible modules to be disassembled, and obtain the position coordinates of the grippers in the working coordinate system of the disassembly and assembly robotic arm. Input the target position coordinates into the disassembly and assembly robotic arm to move it to the gripper position to form a capture. During capture, the gripper of the disassembly and assembly robotic arm is fixedly connected to the gripper, and it is ensured that the two do not slide relative to each other during the assembly test. S5-2. Perception: Measure and calculate the position and orientation of the two large flexible modules to be disassembled relative to the disassembly and assembly robot arm in the working coordinate system of the disassembly and assembly robot arm, and obtain the angle data of each joint of the disassembly and assembly robot arm; S5-3. Disassembly: Based on the data measured in S5-2, the two large flexible modules are disassembled by using the quick-connect joint between the two large flexible modules to be disassembled. S5-4. Repeat steps S5-1 to S5-3 until all N large flexible modules have been disassembled.

9. The experimental method for quantifying the uncertainty in the assembly process of a large flexible module according to claim 4, characterized in that, The specific steps of step S7 are as follows: The uncertainty of the first n modal frequencies and modal damping ratio of the structure after the large flexible module is assembled is calculated by repeating the measured data M times, thereby quantifying the uncertainty of the first n modal frequencies and modal damping ratio brought about by the assembly process, where n is equal to or greater than 3.

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