A rope-driven flexible robotic arm for capturing space debris

Abstract

This utility model relates to the field of space robotic arm technology, and discloses a rope-driven flexible robotic arm for capturing space debris. It includes at least three arm segments connected end-to-end, a base unit, an end effector base, and multiple tethers. The end effector base is installed at the end of the arm segment furthest from the base unit. Each arm segment has a spindle-bellows coupling structure, with adjacent spindle joint units movably connected via bellows and universal joints. The arm segments have flexible deformation capabilities, allowing deformation to be controlled by manipulating the tethers passing through them, thus moving the end effector to a target position and direction. This utility model solves the problems of limited reach and rigid collision with space debris inherent in existing rigid robotic arms, as well as the shortcomings of discontinuous changes and low positioning accuracy in existing flexible robotic arms. It offers advantages such as flexible contact with space debris, continuous deformation, and high positioning accuracy.

Description

Technical Field

[0001] This utility model relates to the field of space robotic arm technology, specifically to a rope-driven flexible robotic arm for capturing space debris in a space environment. Background Technology

[0002] With the development of human spaceflight, space resources are becoming increasingly scarce and precious due to the deteriorating space debris environment. Space debris already poses a serious threat to the safety of space assets. If left unchecked, space debris will cascade and collide, its quantity increasing exponentially, eventually completely occupying near-Earth orbit. Therefore, capturing and removing space debris has become an urgent need.

[0003] Traditional discrete joint rigid robotic arms have been widely used in space missions, but in performing space debris capture tasks, their heavy weight, complex drive structure, and limited operating space are due to the motor-driven joints. Furthermore, rigid collisions with space debris can easily damage the robotic arm itself and generate new debris. Against this backdrop, the advantages of flexible robotic arms become apparent.

[0004] While flexible materials grant robotic arms high compliance, they also reduce their ability to perform external work. Some flexible robotic arms driven by sheet deformation, although ensuring a certain degree of bending and load capacity, exhibit discontinuous changes during movement and experience significant irregular vibrations, making it difficult to stably control their trajectory. Pneumatically driven flexible robotic arms, while exhibiting continuous and smooth deformation, suffer from low repeatability and positioning accuracy. Rope-driven systems, however, avoid the drawbacks of the aforementioned methods and are the preferred solution for clearing space debris. Utility Model Content

[0005] To address the need for high-precision and high-reliability capture technology in space debris removal, this invention provides a rope-driven flexible robotic arm for capturing space debris. This addresses issues in existing robotic arms such as limited reachability, rigid collisions with space debris, discontinuous deformation, and low positioning accuracy. It allows for flexible contact with space debris, continuous deformation, and high positioning accuracy.

[0006] The technical solution adopted by this utility model to solve its technical problem is:

[0007] A rope-driven flexible robotic arm for grasping space debris includes:

[0008] At least three arm segments connected end to end, each arm segment including at least two spindle joint units, and for each arm segment itself and between each arm segment, each pair of adjacent spindle joint units are movably connected by at least three bellows flexible components and a universal joint.

[0009] A base unit, wherein the base unit is movably connected to the arm segment via at least three of the bellows flexible components and one universal joint;

[0010] An end effector base, wherein the end effector base is movably connected to the arm segment via at least three of the bellows flexible components and one of the universal joints;

[0011] Multiple tethers are provided, with one end of each tether connected to the base unit and the other end passing through the spindle joint unit of each arm segment in sequence and being fixedly connected to the spindle joint unit of each arm segment furthest from the base unit, and finally fixedly connected to the end effector base. The arm segment can be kept in a straight state, kept in a bent state, or switched between a straight state and a bent state by adjusting the length of the tether.

[0012] Preferably, the spindle joint unit includes a hollow cylindrical structure along the axial direction, an outer ring structure, and a hollow rib plate for connecting the cylindrical structure and the outer ring structure. The cylindrical structure has circular grooves at both ends, and the inner diameter of the circular groove is equal to the outer diameter of the universal joint to achieve a fit. The sidewall of the circular groove has a through hole for fasteners to pass through and fix the universal joint in the circular groove.

[0013] Note: The hollow structure of the spindle joint unit reduces weight and allows the cables of the space debris capture device mounted on the end effector base to be connected to the satellite body through the hollow structure; the use of hollow ribs achieves weight reduction while maintaining sufficient strength.

[0014] Preferably, at least three sets of boss structures are evenly arranged circumferentially on the outer side of the outer ring structure. Each set of boss structures includes a circumferentially centered boss arranged along the circumferential direction and two second bosses located on both sides of the circumferentially centered first boss. The first boss has multiple axial through holes for passing through the tie rope, and each of the two second bosses has an axial through hole for fixing to the corrugated tube flexible component.

[0015] Note: The distance between the location where the bellows flexible component is installed and the center of the spindle joint unit needs to be equal to the radius of curvature of the bellows flexible component. Manufacturing an outer ring with a small radius and extending a boss structure from the outer ring to install the bellows flexible component can reduce weight as much as possible.

[0016] Preferably, the bellows flexible component includes connecting portions located at both ends in the axial direction. The longitudinal cross-section of the connecting portion is L-shaped and has through holes for fixing to the corresponding spindle joint unit, base unit or end effector base by fasteners.

[0017] Description: The main body of the bellows flexible component is made of flexible material, with a multi-layered corrugated structure and spring-like properties, but with better radial load bearing capacity than a spring; it can bend into the required shape when under force and transfer the force to the next bellows flexible component and spindle joint unit.

[0018] Preferably, the base unit includes a first joint structure having the same main structure as the spindle joint unit, and having the circular groove and a flat plate structure only at one axial end. Both the first joint structure and the flat plate structure have several through holes for passing through the tether and fixing to the corrugated tube flexible component.

[0019] Note: The flat panel structure has several through holes for connecting to the satellite and fixing the motor.

[0020] Preferably, the end effector base includes a second joint structure, a box-shaped actuator base, and a cylindrical transition structure. The second joint structure has the same main structure as the spindle joint unit, and the circular groove is provided only at one axial end. The second joint structure is fixedly connected to the box-shaped actuator base through the cylindrical transition structure.

[0021] Note: The square box actuator base is used to flexibly install different capture tools according to different mission objectives.

[0022] The rope-driven flexible robotic arm for grasping spatial debris provided by this utility model allows for the following behavior for each spindle joint unit: when the tether in one direction tightens, the spindle joint unit bends in the plane defined by the point of action of the tether and the axis; when the tethers in two directions tighten simultaneously, the spindle joint unit bends in the plane defined by the point of action of the unclenged tether and the axis; when the tethers on all three sides tighten simultaneously, the spindle joint unit does not compress along the axis. The bending and deformation of the flexible robotic arm are achieved by controlling the lengths of different tethers. For the flexible robotic arm as a whole, the lengths of several tethers (equal to the number of motor sets) are controlled through the drive of several sets of motors, adjusting the different postures of several arm segments to control the movement of the flexible robotic arm.

[0023] The beneficial effects of this utility model are reflected in the following aspects:

[0024] First, the flexible robotic arm for capturing space debris provided by this invention employs a corrugated flexible component combined with a universal joint to connect the spindle joint unit, resulting in extremely high flexibility. When contacting or capturing space debris, it can effectively absorb collision energy, achieving flexible contact and significantly reducing the risk of damage to the robotic arm itself or the debris caused by rigid collisions, thereby generating new space debris and fundamentally improving mission safety.

[0025] Secondly, the rope-driven flexible robotic arm for grasping space debris provided by this invention directly transmits tension through a rope drive, resulting in high driving efficiency and overcoming the shortcomings of low repeatability in pneumatic drives. By precisely controlling the rope length, high repeatability in joint angles and end effector base positions can be achieved.

[0026] Third, the spindle joint unit in the rope-driven flexible robotic arm for capturing space debris provided by this utility model adopts a hollow rib design, which effectively reduces the weight of the unit; the overall drive system is based on the tether and motor assembly, which significantly simplifies the drive structure and reduces the total weight and structural complexity of the system compared with the joint motor structure of the traditional rigid robotic arm and the pump and valve pipeline of the pneumatic system. Attached Figure Description

[0027] Figure 1 This is a perspective view of Embodiment 1 of the present utility model;

[0028] Figure 2 This is a three-dimensional schematic diagram of the flexible arm segment of Embodiment 1 of this utility model;

[0029] Figure 3 This is a three-dimensional schematic diagram of the base unit of Embodiment 1 of this utility model;

[0030] Figure 4 This is a three-dimensional schematic diagram of the end effector base of Embodiment 1 of this utility model;

[0031] Figure 5 This is a three-dimensional schematic diagram of the spindle joint unit of Embodiment 1 of this utility model;

[0032] Figure 6 This is a three-dimensional schematic diagram of the corrugated flexible component of Embodiment 1 of this utility model;

[0033] Figure 7 This is a schematic diagram of the arm segment bending principle in Embodiment 1 of this utility model;

[0034] 100 - Flexible robotic arm; 200 - Arm segment; 210 - Spindle joint unit; 211 - Hollow cylindrical structure; 212 - Circular groove; 213 - Hollowed-out rib plate; 214 - Outer ring structure; 215 - Central boss; 216 - Side bosses; 220 - Corrugated flexible component; 221 - Axial end connection; 230 - Universal joint; 240 - Tie rope; 300 - Base unit; 301 - Partial joint structure; 302 - Flat plate structure; 400 - End effector base; 401 - Partial joint structure; 402 - Box-shaped actuator base; 403 - Cylindrical transition structure. Detailed Implementation

[0035] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0036] It should be noted that, unless otherwise specified, when a feature is referred to as "fixed" or "connected" to another feature, it can be directly fixed or connected to the other feature, or it can be indirectly fixed or connected to the other feature. Furthermore, the descriptions of "upper," "lower," "left," "right," "top," and "bottom" used in this utility model are only relative to the relative positional relationships of the various components of this utility model in the accompanying drawings.

[0037] Furthermore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and not for limiting the scope of the invention. The term "and / or" as used herein includes any combination of one or more of the associated listed items.

[0038] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various elements, these elements should not be limited to these terms. These terms are only used to distinguish elements of the same type from one another. For example, without departing from the scope of this disclosure, a first element may also be referred to as a second element, and similarly, a second element may also be referred to as a first element.

[0039] Example 1:

[0040] like Figure 1 As shown, this embodiment discloses a rope-driven flexible robotic arm for capturing space debris. The robotic arm includes three arm segments 200 connected end to end, a base unit 300, an end effector base 400, and multiple tethers 240.

[0041] like Figure 2 As shown, in this embodiment, the arm segment 200 includes: 5 spindle joint units 210. For each arm segment 200 itself and between each arm segment 200, every two adjacent spindle joint units 210 are movably connected by 3 bellows flexible components 220 and 1 universal joint 230. The bellows flexible components 220 allow the tension applied to the tether fixing point to be evenly transmitted to each bellows flexible component 220, so as to realize the continuous and controllable deformation of the flexible robotic arm. The universal joint 230 provides flexible angle changing capability, and also provides a certain rigidity to improve the load-bearing capacity of the robotic arm.

[0042] The base unit 300 and the arm segment 200 are movably connected by at least three bellows flexible components 220 and a universal joint 230.

[0043] The end effector base 400 and the arm segment 200 are movably connected by at least three bellows flexible components 220 and a universal joint 230;

[0044] One end of each tether 240 is connected to the base unit 300, and the other end passes through the spindle joint unit 210 of each arm segment 200 in sequence and is fixedly connected to the spindle joint unit 210 of each arm segment 200 that is furthest from the base unit 300, and is finally fixedly connected to the end effector base 400. By adjusting the length of the tether 240, the arm segment 200 can be controlled to remain in a straight state, remain in a bent state, or switch between a straight state and a bent state.

[0045] like Figure 5 As shown, the spindle joint unit 210 of this embodiment includes a hollow cylindrical structure 211 along the axial direction, an outer ring structure 214, and a hollow rib plate 213 for connecting the cylindrical structure 211 and the outer ring structure 214. The hollow structural design of the cylindrical structure 211 can reduce weight and allow the cable attached to the space debris capture device installed on the end effector base 400 to be connected to the satellite body through the hollow cylindrical structure 211. The hollow rib plate 213 achieves the effect of weight reduction while having sufficient strength. The two ends of the cylindrical structure 211 have circular grooves 212. The inner diameter of the circular grooves 212 is equal to the outer diameter of the universal joint 230 to achieve a fit. The sidewall of the circular grooves 212 has through holes for fasteners (such as bolts) to pass through and fix the universal joint 230 in the circular grooves 212.

[0046] like Figure 5 As shown, three sets of boss structures are evenly arranged circumferentially on the outer side of the outer ring structure 214. Each set of boss structures includes a centrally located circumferentially arranged boss 215 and two second bosses 216 located on either side of the centrally located boss 215. The first boss 215 has multiple axial through holes for the rope 240 to pass through, and each of the two second bosses 216 has one axial through hole for fixing to the bellows flexible component 220. The distance between the location where the bellows flexible component 220 is installed and the center of the spindle joint unit 210 needs to be equal to the radius of curvature of the bellows flexible component 220. Manufacturing an outer ring with a small radius and extending the boss structure from the outer ring to install the bellows flexible component 220 can reduce weight as much as possible.

[0047] like Figure 6As shown, the bellows flexible component 220 includes connecting portions 221 located at both axial ends. The longitudinal cross-section of the connecting portion 221 is L-shaped and has through holes for fixing to the corresponding spindle joint unit 210, base unit 300, or end effector base 400 by fasteners (e.g., bolts). The main body of the bellows flexible component 220 is made of a flexible material (e.g., nylon). The bellows flexible component 220 has a multi-layered corrugated structure and spring-like properties, but has a better ability to withstand radial loads than a spring. When subjected to force, it can bend into the desired shape and transmit the force to the next bellows flexible component 220 and spindle joint unit 210.

[0048] like Figure 3 As shown, the base unit 300 includes a first joint structure 301, which has the same main structure as the spindle joint unit 210, and has a circular groove 212 only at one axial end, presenting a structure of half a spindle joint unit 210; and a flat plate structure 302. Both the first joint structure 301 and the flat plate structure 302 have several through holes for passing through the tether 240 and fixing to the corrugated flexible component 220. The flat plate structure 302 has several through holes for connecting to the satellite and fixing the motor. The motor is an external structure, which is in the prior art.

[0049] like Figure 4 As shown, the end effector base 400 includes a second joint structure 401, a box-shaped actuator base 402, and a cylindrical transition structure 403. The second joint structure 401 has the same main structure as the spindle joint unit 210, and only has a circular groove 212 at one axial end, which also presents the structure of half a spindle joint unit 210, for fixing to the bellows flexible component 220 and universal joint 230 at the end of the arm segment. The second joint structure 401 is fixedly connected to the box-shaped actuator base 402 through the cylindrical transition structure 403. The box-shaped actuator base 402 is used to flexibly install different capture tools according to different mission objectives.

[0050] like Figure 1 and Figure 2As shown, in this embodiment, one end of the tether 240 is connected to the base unit 300 and wound around the motor mounted on the base unit 300. The tether is contracted or extended by controlling the rotation of the motor. The other end is connected to the spindle joint unit 210 at one end of one of the arm segments 200 or the end effector base 400. The length of the tether 240 is adjusted to control the arm segment 200 to remain in a straight state, a bent state, or switch between straight and bent states. In this embodiment, there are three arm segments 200 and nine tethers 240. Three tethers are connected to the spindle joint unit at the end of the arm segment closest to the base unit 300, three tethers are connected to the spindle joint unit at the farthest end of the middle arm segment, and three tethers are connected to the end effector base 400. Each of the three arm segments can be bent in different directions to achieve flexible deformation.

[0051] Example 2: The difference from Example 1 is that the robotic arm includes 5 arm segments 200 connected end to end.

[0052] Example 3: The difference from Example 1 is that the robotic arm includes 8 arm segments 200 connected end to end.

[0053] Example 4: Unlike Example 1, each arm segment 200 includes 6 spindle joint units 210.

[0054] Example 5: Unlike Example 1, each arm segment 200 includes 10 spindle joint units 210.

[0055] Example 6: Unlike Example 1, each pair of adjacent spindle joint units 210 are movably connected by nine bellows flexible components 220 and two universal joints 230.

[0056] Example 7: Unlike Example 1, each pair of adjacent spindle joint units 210 are movably connected by 12 bellows flexible components 220 and 2 universal joints 230.

[0057] Example 8: The difference from Example 1 is that four sets of boss structures are evenly arranged circumferentially on the outer side of the outer ring structure 214.

[0058] Example 9: The difference from Example 1 is that five sets of boss structures are evenly arranged circumferentially on the outer side of the outer ring structure 214.

[0059] It should be noted that the above embodiments are merely examples, intended to illustrate one situation, and do not constitute a limitation on the scope of protection outlined in the claims. As for the parameters in the above embodiments, those skilled in the art can modify them as needed to conform to actual applications, and no special limitations are made here.

[0060] In the description of this specification, the references to terms such as "embodiment," "example," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, those skilled in the art can combine or combine the different embodiments or examples described in this specification and their features therein without creating contradiction.

[0061] While embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and alterations to the above embodiments within the scope of the present invention.

Claims

1. A rope-driven flexible robotic arm for grasping space debris, characterized in that, include: At least three arm segments (200) connected end to end, each arm segment (200) including at least two spindle joint units (210), and each pair of adjacent spindle joint units (210) are movably connected by at least three bellows flexible components (220) and a universal joint (230). The base unit (300) is movably connected to the arm segment (200) via at least three of the bellows flexible components (220) and one of the universal joints (230); An end effector base (400) is movably connected to the arm segment (200) via at least three of the bellows flexible components (220) and a universal joint (230); Multiple tethers (240) are provided, one end of each tether (240) is connected to the base unit (300), and the other end passes through the spindle joint unit (210) of each arm segment (200) in sequence and is fixedly connected to the spindle joint unit (210) of each arm segment (200) that is furthest from the base unit (300), and is finally fixedly connected to the end effector base (400). The arm segment (200) can be kept in a straight state, kept in a bent state, or switched between a straight state and a bent state by adjusting the length of the tether (240). The spindle joint unit (210) includes a hollow cylindrical structure (211) along the axial direction, an outer ring structure (214), and a hollow rib plate (213) for connecting the cylindrical structure (211) and the outer ring structure (214). The cylindrical structure (211) has circular grooves (212) at both ends. The inner diameter of the circular groove (212) is equal to the outer diameter of the universal joint (230) to achieve a fit. The side wall of the circular groove (212) has a through hole for fasteners to pass through and fix the universal joint (230) in the circular groove (212).

2. The rope-driven flexible robotic arm for capturing space debris according to claim 1, characterized in that, At least three sets of boss structures are evenly arranged circumferentially on the outer side of the outer ring structure (214). Each set of boss structures includes a circumferentially centered boss (215) and two second bosses (216) located on both sides of the circumferentially centered first boss (215). The first boss (215) has multiple axial through holes for passing through the tie rope (240). Each of the two second bosses (216) has an axial through hole for fixing to the corrugated flexible component (220).

3. The rope-driven flexible robotic arm for capturing space debris according to claim 1, characterized in that, The bellows flexible component (220) includes connecting portions (221) located at both ends of the axial direction. The longitudinal section of the connecting portion (221) is L-shaped and has through holes for fixing to the corresponding spindle joint unit (210), base unit (300) or end effector base (400) by fasteners.

4. The rope-driven flexible robotic arm for capturing space debris according to claim 1, characterized in that, The base unit (300) includes a first joint structure (301), which has the same main structure as the spindle joint unit (210), and is provided with the circular groove (212) only at one axial end, and a flat plate structure (302). The first joint structure (301) and the flat plate structure (302) are each provided with several through holes for passing through the tether (240) and fixing to the corrugated flexible component (220).

5. The rope-driven flexible robotic arm for grasping space debris according to claim 1, characterized in that, The end effector base (400) includes a second joint structure (401), a box-shaped actuator base (402), and a cylindrical transition structure (403). The second joint structure (401) has the same main structure as the spindle joint unit (210), and the circular groove (212) is provided only at one axial end. The second joint structure (401) is fixedly connected to the box-shaped actuator base (402) through the cylindrical transition structure (403).

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