A stable adhesion device for spacecraft on-orbit service and its working method

Abstract

The present invention provides a stable adhesion device for on-orbit service of spacecraft and its working method. The device includes a drive system, a flexible adhesion module and a variable stiffness damper. The drive system is installed on the variable stiffness damper and is connected to the flexible adhesion module. The external load device interface is located on the variable stiffness damper. The flexible adhesion module and the variable stiffness damper are provided with adhesion layers of different structures. According to the structural bearing capacity and adhesion establishment conditions of different adhesion layers, the adhesion order of different adhesion layers is adjusted to achieve stable adhesion and smooth detachment with the target surface. The present invention improves the adhesion stability between the load device and the target surface under collision conditions. The variable stiffness damper absorbs the vibration energy of the landing process and reduces the impact. The drive system provides continuous tangential force to the gecko-like bristles during the landing process. The combined force of the tangential force and the normal contact force during the landing collision process improves the adhesion effect of the gecko-like bristles. Finally, stable adhesion is achieved.

Description

Technical Field

[0001] The invention relates to a stable adhesion device for on-orbit service of a spacecraft and a working method thereof. Background Art

[0002] Spacecraft on-orbit services include target capture, fault inspection, and detection and identification. A key prerequisite for achieving these tasks is that the payload equipment can be stably attached to the spacecraft surface and prevent it from falling off due to the inertial impact of landing on the spacecraft surface. At the same time, the payload equipment itself and the spacecraft surface structure cannot be damaged or failed due to shock and vibration. This urgently requires an adhesion device that can not only provide a cushioning effect but also enhance the adhesion effect, achieving stable and reliable adhesion.

[0003] Existing dry-adhesion technologies and devices in space often use devices with gecko-like bristle structures to adhere and capture space targets. This increases the contact area between the bristles and the target surface, enhancing the van der Waals force and thus increasing normal adhesion. However, these technologies and devices do not adequately address the impact oscillations generated by the structure during landing and collision on the spacecraft surface, leading to adhesion failure and instability. This poses a risk of payload loss and loss. Summary of the Invention

[0004] Based on the aforementioned technical issues that existing dry adhesion technologies / devices do not adequately address adhesion failure and instability caused by the impact oscillations generated during landing and collision with the spacecraft surface, and that payload equipment may be at risk of detachment and loss, a stable adhesion device and operating method for spacecraft on-orbit service are provided. This invention primarily utilizes a variable-stiffness damper to absorb vibration energy during landing and reduce system amplitude. The drive system provides a continuous tangential force to the gecko-like bristles during landing. The combined force of this tangential force and the normal contact force during the landing collision enhances the adhesion of the gecko-like bristles, ultimately achieving stable adhesion.

[0005] The technical means adopted in the present invention are as follows:

[0006] A stable adhesion device for on-orbit spacecraft service comprises: a drive system, a flexible adhesion module, and a variable stiffness damper. The drive system is located above the flexible adhesion module and mounted on the variable stiffness damper located at the center. The drive system is connected to the flexible adhesion module to drive the flexible adhesion module to achieve movement. An interface for external load equipment is located on the variable stiffness damper.

[0007] The flexible adhesion module and the variable stiffness damper are both provided with adhesion layers of different structures. The adhesion order of the different adhesion layers is adjusted according to the structural bearing capacity and adhesion establishment conditions of the different adhesion layers to achieve stable adhesion and smooth detachment with the target surface.

[0008] Furthermore, a plurality of the flexible adhesion modules are provided and arranged around the circumference of the variable stiffness damper.

[0009] Furthermore, the drive system includes a one-way SMA spring I, a ceramic fiber rope, a plurality of drive brackets, a plurality of lever assemblies, and a plurality of ordinary springs; the one-way SMA spring I is electrically heated to achieve contraction, and is cooled when the power is turned off, and then extended under the tension of the ordinary spring;

[0010] The driving bracket includes a sleeve and a cantilever beam with a slotted hole, the cantilever beam is fixedly connected to one end of the sleeve, the sleeve is connected to the variable stiffness damper, a plurality of cantilever beams are circumferentially distributed around the central axis of the sleeve, and the four sides of the cantilever beam are penetrated by interconnected slots;

[0011] The lever assembly includes a lever with a through hole, a slot pin and a support frame, the power end of the lever is inserted into the slot, the through hole is located at the power end of the lever, the slot pin is located at the resistance end of the lever and is connected to the flexible adhesion module, the fulcrum of the lever is connected to the support frame and rotates, the support frame is fixedly connected to the other end of the sleeve, and multiple support frames are circumferentially distributed around the central axis of the sleeve; the flexible adhesion module is also connected to the lever and the support frame;

[0012] The ceramic fiber rope passes through the multiple through holes in sequence and is connected to both ends of the one-way SMA spring I to form a closed loop around the sleeve;

[0013] An ordinary spring is installed in each cantilever beam. The ordinary spring is always in a stretched recovery state. The two ends of the ordinary spring are respectively connected to the power end of the lever and the inner wall of the end of the slot away from the sleeve;

[0014] During operation, the one-way SMA spring I contracts after being energized and heated, and the diameter of the closed loop shrinks, thereby pulling the power end of the lever toward the sleeve; the stiffness of the one-way SMA spring I gradually decreases during the cooling process when the power is turned off. Under the action of the recovery force of the ordinary spring, the one-way SMA spring I gradually extends, and at the same time, the power end of the lever moves away from the sleeve. The one-way SMA spring I is then energized and heated and the process is repeated. The power end of the lever can swing back and forth in the slot, and under the action of the fulcrum, the resistance end of the lever is driven to swing back and forth, thereby driving the flexible adhesion module.

[0015] Furthermore, the flexible adhesion module includes a drawstring, a flexible foot, and an adhesion layer firmly attached to the sole of the foot. The adhesion layer is an array of gecko-like bristles, which is used to adhere to the target surface. The flexible foot includes a plurality of tooth grooves distributed on the dorsum of the foot, a support rod and a power rod connected to the heel, the tooth grooves are provided with holes, and one end of the power rod is provided with a guide groove.

[0016] The pull rope passes through the holes on the plurality of tooth grooves in sequence, and the two ends of the pull rope are respectively connected to the free end of the flexible foot and the power end of the lever. When the pull rope is pulled, the flexible foot bends to achieve the detachment of the gecko-like bristle array from the target surface;

[0017] The end of the support rod is inserted into the support frame and moves back and forth in the support frame along the circumferential radius of the sleeve;

[0018] The guide groove cooperates with the groove pin at the lever resistance end to form a groove pin pair, which converts the circular motion of the lever resistance end into linear motion, drives the flexible foot to reciprocate along the radius of the sleeve, and forms a tangential force on the gecko-like bristle array. When the tangential force points to the sleeve, adhesion occurs, and when the tangential force moves away from the sleeve, the adhesion is released; under the dual action of the pull rope and the lever resistance end, the desorption process of the gecko-like bristle array is easier.

[0019] Furthermore, the variable stiffness damper includes a piston buffer rod, a one-way SMA spring II and a cylinder; an adhesive layer is provided at the head end of the piston buffer rod, and the adhesive layer is a flexible dry rubber pad, which contacts the target surface and establishes initial adhesion during the landing collision process;

[0020] The tail end of the piston buffer rod is fixedly connected to the tail end of the one-way SMA spring II, and the head end of the one-way SMA spring II is fixedly connected to the upper surface of the driving bracket. The piston buffer rod passes through the one-way SMA spring II along the axis of the one-way SMA spring II. At the beginning of the landing collision, the piston buffer rod contacts the target surface, and the one-way SMA spring II tends to be stretched. The cylinder is placed on the upper surface of the driving bracket, the one-way SMA spring II is located in the cylinder, the tail end of the piston buffer rod is inserted into the cylinder, and the sleeve of the driving bracket is sleeved on the outer wall of the piston buffer rod.

[0021] By energizing the one-way SMA spring II, the one-way SMA spring II is contracted, and the piston buffer rod contacts the collision target surface, which causes the one-way SMA spring II to stretch; according to the pre-landing height, the energizing current of the one-way SMA spring II is adjusted. The stiffness of the one-way SMA spring II is different at different temperatures, and the buffering effect provided by the variable stiffness damper is also different.

[0022] Furthermore, the flexible foot is made of flexible elastic material; several of the tooth grooves are unevenly distributed on the back of the flexible foot, with different spacing and depths; the depth of several tooth grooves gradually decreases from the toe to the heel of the flexible foot, and the degree of curling of the flexible foot gradually decreases when the pull rope is pulled; when the pull rope is pulled, the flexible foot curls more at the toe, and as the depth of the tooth groove decreases, the degree of curling also gradually decreases.

[0023] Furthermore, the gecko-like bristles in the gecko-like bristle array are a directional structure. After a shear force in a specific direction is applied, the contact area between the directional structure and the target surface increases, thereby producing an adhesion effect; the gecko-like bristle array is unevenly distributed, and the array density gradually decreases from the toe to the heel of the flexible foot, that is, the adhesion area is mainly located in the area near the toe of the flexible foot; when the flexible adhesion module contacts the target surface, the flexible foot is in a curled state, and the area near the heel contacts the target surface first. The structural stress is greater than that of other parts, and failure damage is prone to occur. Based on this, a sparse gecko-like bristle density is set in the area near the heel to reduce the risk of failure and loss, and also helps desorption.

[0024] Furthermore, the flexible dry adhesive pad is formed by a micro-nano structure array, and the cross-sectional shape of the micro-nano structure is "⊥"-shaped, which can withstand a large normal impact force and produce adhesion, and the tangential force will not cause the micro-nano structure to produce adhesion.

[0025] Furthermore, the stable adhesion device is driven as a whole by a smart material shape memory alloy.

[0026] The present invention also provides a method for operating a stable adhesion device for on-orbit service of a spacecraft, comprising the following steps:

[0027] Before landing, the one-way SMA spring I is heated and contracts. Under the action of the pull rope and lever, the flexible foot curls and moves away from the sleeve. At this time, the projected area of the adhesion surface of the gecko-like bristle structure on the target surface increases, and the orientation of the gecko-like bristles is conducive to establishing adhesion.

[0028] During landing, the flexible dry rubber pad first contacts the landing surface and establishes initial adhesion under the action of normal preload. The one-way SMA spring II is stretched, absorbing the kinetic energy of the mechanism, stabilizing the system and reducing the instantaneous contact force generated by the collision between the flexible foot and the landing surface without damaging the microstructure of the gecko-like bristles. Afterwards, the heel of the flexible foot contacts the target surface. At the same time, as the one-way SMA spring I gradually cools and its stiffness decreases, the tension it provides is less than the restoring tension of an ordinary spring. The lever gradually resets, the flexible foot no longer curls and moves toward the sleeve, generating a tangential force on the gecko-like bristles. Under the combined action of the normal contact force and the tangential force, the adhesion of the gecko-like bristles is enhanced, and the amplitude of the mechanical system is significantly reduced by the action of the variable stiffness damper, achieving stable adhesion.

[0029] After landing, when it is necessary to detach from the adhesion, the one-way SMA spring II is energized and heated to cause it to contract. The piston buffer rod will not move normally due to contact with the target surface. Only the cylinder and the flexible foot can move away from the target surface. At the same time, the one-way SMA spring I is energized and heated to cause it to contract. Under the combined action of the two, the flexible foot can easily detach from the target surface.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1. The stable adhesion device and operating method provided by this invention for on-orbit spacecraft servicing improve the adhesion stability between payload equipment and target surfaces under collision conditions. A variable-stiffness damper absorbs vibration energy during landing, reducing system amplitude. The drive system provides a continuous tangential force to the gecko-like bristles during landing. The combined force of this tangential force and the normal contact force during the landing collision enhances the adhesion of the gecko-like bristles. Ultimately, stable adhesion is achieved.

[0032] 2. The stable adhesion device and working method provided by the present invention for on-orbit service of spacecraft propose a new method of detaching the gecko bristles. By pulling the rope to curl the flexible instep, using the lever to move the flexible foot outward, and relying on the piston buffer rod to move the flexible foot upward, the detachment process of the gecko bristles is easier.

[0033] 3. The stable adhesion device and working method for on-orbit service of spacecraft provided by the present invention are all driven by shape memory alloy (SMA), and the driving system is simple, which reduces the structural weight.

[0034] In summary, the application of the technical solution of the present invention can solve the problem that the existing dry adhesion technology / device does not fully pay attention to the adhesion failure and instability caused by the impact vibration generated when the structure lands and collides on the surface of the spacecraft, and the payload equipment is at risk of falling off and being lost.

[0035] Based on the above reasons, the present invention can be widely promoted in the fields of spacecraft and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0037] Figure 1 Schematic diagram of the overall structure of an embodiment of the present invention (taking four circular arrays of flexible adhesion modules and drive systems as an example).

[0038] Figure 2 It is a partially enlarged schematic diagram of the overall structure in an embodiment of the present invention (for ease of observation, redundant symmetrical structures are not shown).

[0039] Figure 3 Schematic diagram of the working principle of the device in an embodiment of the present invention, where (a) is before landing, (b) is during landing, and (c) is after landing.

[0040] In the figure: 1. Drive system; 101. One-way SMA spring I; 102. Ceramic fiber rope; 103. Drive bracket; 104. Lever assembly; 105. Ordinary spring; 103a. Sleeve; 103b. Slotted hole; 103c. Cantilever beam; 104a. Through hole; 104b. Lever; 104c. Slotted pin; 104d. Support frame;

[0041] 2. Flexible adhesion module; 201. Pull rope; 202. Flexible foot; 203. Gecko-like bristle array; 202a. Tooth groove; 202b. Support rod; 202c. Power rod; 202d. Guide groove;

[0042] 3. Variable stiffness damper; 301. Piston buffer rod; 302. One-way SMA spring II; 303. Cylinder; 301a. Flexible dry rubber pad. DETAILED DESCRIPTION

[0043] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0045] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0046] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0047] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0048] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0049] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0050] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a stable adhesion device that can reduce impact and enhance adhesion when landing on the surface of a spacecraft, thereby providing a guarantee for the payload equipment to carry out on-orbit services.

[0051] A self-loading stable adhesion device for on-orbit service of spacecraft includes a drive system, a flexible adhesion module and a variable stiffness damper; the drive system is located above the flexible adhesion module, and both are installed on the variable stiffness damper at the center position; the interface for external load equipment is located on the variable stiffness damper, and the flexible adhesion module and the variable stiffness damper are both provided with adhesion layers of different structures.

[0052] Preferably, the drive system includes a drive bracket, a lever assembly, an ordinary spring, a ceramic fiber rope and a one-way SMA spring I; the drive bracket includes a sleeve and a cantilever beam with a slotted hole; the lever assembly includes a lever with a through hole, a slot pin and a support frame, the through hole is located at the power end of the lever, the slot pin is located at the resistance end of the lever, and is used to connect the flexible adhesion module, and the fulcrum of the lever is located on the support frame; the two ends of the ordinary spring are respectively connected to the inner wall of the slot at the free end of the cantilever beam (that is, the inner wall of the end of the slot away from the sleeve) and the power end of the lever, and the power end of the lever swings in the slot; the ceramic fiber rope passes through the through hole and is connected to the two ends of the one-way SMA spring I to form a closed loop around the sleeve.

[0053] Preferably, the flexible adhesion module includes a flexible foot, a pull rope and an array of gecko-like bristles firmly attached to the sole of the foot; the flexible foot includes a support rod and a power rod distributed on the tooth groove and the heel of the dorsum of the foot, and a guide groove is provided at one end of the power rod; the pull rope passes through the hole on the tooth groove, and the two ends are respectively connected to the free end of the flexible foot and the power end of the lever, and when the pull rope is pulled, the flexible foot bends; the support rod moves back and forth in the support frame along the circumferential radius of the sleeve; the slot pin at the resistance end of the lever cooperates with the guide groove to form a slot pin pair, which converts the circular motion of the resistance end of the lever into linear motion, driving the flexible foot to reciprocate along the circumferential radius of the sleeve.

[0054] Preferably, the flexible foot is made of flexible elastic material; the tooth grooves are unevenly distributed on the flexible instep, with different spacing and depths; the depth of the tooth grooves gradually decreases from the toe to the heel of the flexible foot, and the curling degree of the flexible foot gradually decreases when the draw rope is pulled; when the draw rope is pulled, the flexible foot curls more at the toe, and as the depth of the tooth grooves decreases, the curling degree gradually decreases.

[0055] Preferably, the gecko-like bristles are a directional structure. After applying shear force in a specific direction, the contact area between the structure and the target surface increases, thereby producing an adhesion effect; the gecko-like bristle array is uneven, and the array density gradually decreases from the toe to the heel of the flexible foot.

[0056] Preferably, the variable stiffness damper includes a piston buffer rod, a one-way SMA spring II and a cylinder; a flexible dry rubber pad is provided at the head end of the piston buffer rod; the tail end of the piston buffer rod is fixedly connected to the tail end of the one-way SMA spring II, the head end of the one-way SMA spring II is fixedly connected to the upper surface of the driving bracket 103, and the piston buffer rod passes through along the axis of the one-way SMA spring II; the cylinder is placed on the upper surface of the driving bracket 103, the one-way SMA spring II is located in the cylinder, and the tail end of the piston buffer rod is inserted into the cylinder and moves along the axis of the cylinder.

[0057] Preferably, the flexible dry adhesive pad is formed by a micro-nano structure array, and the cross-sectional shape of the micro-nano structure is "⊥"-shaped, which can withstand a large normal impact force and produce adhesion, and the tangential force will not cause the micro-nano structure to produce adhesion.

[0058] Preferably, the flexible adhesion modules and the driving system may be arranged in multiple groups around the circumference of the sleeve.

[0059] Preferably, the self-loading stable adhesion devices for on-orbit service of spacecraft are all driven by smart material shape memory alloy (SMA).

[0060] Example 1

[0061] like Figure 1 As shown, an embodiment of the present invention provides a self-loading stable adhesion device for spacecraft on-orbit servicing, comprising a drive system 1, four flexible adhesion modules 2, and a variable stiffness damper 3. The drive system 1 is positioned above the flexible adhesion module 2, and both are mounted on the centrally located variable stiffness damper 3. The interface for external load equipment is located on the variable stiffness damper 3. Both the flexible adhesion module 2 and the variable stiffness damper 3 are provided with adhesion layers of varying structures. The adhesion order of the different adhesion layers is adjusted based on their structural load-bearing capacity and adhesion establishment conditions, achieving stable adhesion and smooth detachment. In this embodiment, the four flexible adhesion modules 2 are symmetrically distributed along the circumference.

[0062] like Figure 1 、 2As shown, the drive system 1 includes four one-way SMA springs I 101, a ceramic fiber rope 102, four drive brackets 103, four lever assemblies 104, and four conventional springs 105. The one-way SMA springs I 101 are electrically heated to contract, and then cooled when powered off, allowing them to extend under the tension of the conventional springs 105. Each drive bracket 103 includes a sleeve 103a and a cantilever beam 103c with a slot 103b. The cantilever beam 103c is fixedly connected to one end of the sleeve 103a, which is connected to a variable stiffness damper. The four cantilever beams 103c are evenly distributed circumferentially around the central axis of the sleeve 103a, and interconnected slots 103b are defined through all four sides of the cantilever beams 103c. The lever assembly 104 includes a lever 104b with a through hole 104a, a slot pin 104c and a support frame 104d. The power end of the lever 104b is inserted into the slot 103b. The through hole 104a is located at the power end of the lever 104b ( Figure 2 The slot pin 104c is located at the resistance end of the lever 104b ( Figure 2 The lower end of the lever 104b in the sleeve 103a) is connected to the flexible adhesion module 2, the fulcrum of the lever 104b is located on the support frame 104d (the fulcrum of the lever 104b is connected to the support frame 104d and rotates), the support frame 104d is fixedly connected to the other end of the sleeve 103a, and the four support frames 104d are evenly distributed circumferentially around the central axis of the sleeve 103a; the flexible adhesion module 2 is also connected to the lever 104b and the support frame 104d. The ceramic fiber rope 102 passes through the four through holes 104a in sequence and is connected to the two ends of the four one-way SMA springs Ⅰ 101 to form a closed loop around the sleeve 103a. An ordinary spring 105 is installed in each cantilever beam 103c. The ordinary spring 105 is always in a stretched recovery state. The two ends of the ordinary spring 105 are respectively connected to the power end of the lever 104b and the inner wall of the end of the slot 103b away from the sleeve 103a (such as Figure 2 The left end of the common spring 105 is connected to the power end of the lever 104b, and the right end is connected to the inner wall of the right end of the slot 103b. The power end of the lever 104b swings within the slot 103b. During operation, the one-way SMA spring I 101 contracts after being energized and heated, reducing the diameter of the closed loop and pulling the power end of the lever 104b toward the sleeve 103a. During the cooling process after the one-way SMA spring I 101 is powered off, its stiffness gradually decreases. Under the restoring tension of the common spring 105, the one-way SMA spring I 101 gradually extends, and the power end of the lever 104b moves away from the sleeve 103a. The one-way SMA spring I 101 is then energized and heated, and the process is repeated. The power end of the lever 104b can then swing back and forth within the slot 103b. Under the action of the fulcrum, the resistance end of the lever 104b can also swing back and forth, thereby driving the flexible adhesive module 2.

[0063] like Figure 1 、 2 As shown, the flexible adhesion module 2 includes a pull rope 201, a flexible foot 202, and an adhesion layer firmly attached to the sole of the foot. The adhesion layer is a gecko-like bristle array 203, which is used to adhere to the target surface; the flexible foot 202 includes a plurality of tooth grooves 202a distributed on the dorsum of the foot and a support rod 202b and a power rod 202c connected to the heel. The tooth grooves 202a are penetrated by holes, and one end of the power rod 202c is provided with a guide groove 202d; the pull rope 201 passes through the holes on the plurality of tooth grooves 202a in sequence, and the two ends are respectively connected to the free end ( Figure 2 The right end of the middle flexible foot 202 is connected to the power end of the lever 104b. When the pull rope 201 is pulled, the flexible foot 202 bends, thereby causing the gecko-like bristle array 203 to detach from the target surface; the end of the support rod 202b is inserted into the support frame 104d and moves back and forth in the support frame 104d along the circumferential radius direction of the sleeve 103a; the groove pin 104c at the resistance end of the lever 104b cooperates with the guide groove 202d to form a groove pin pair, which converts the circular motion of the resistance end of the lever 104b into linear motion, driving the flexible foot 202 to reciprocate along the circumferential radius direction of the sleeve 103a, forming a tangential force on the gecko-like bristle array 203. When the tangential force points to the sleeve 103a, adhesion occurs, and when the tangential force deviates from the sleeve 103a, detachment occurs; under the dual action of the pull rope 201 and the resistance end of the lever 104b, the desorption process of the gecko-like bristle array 203 is easier.

[0064] like Figure 2 As shown, the flexible foot 202 is made of a flexible elastic material; a plurality of tooth grooves 202a are unevenly distributed on the instep of the flexible foot 202, with different spacings and depths; the depth of the plurality of tooth grooves 202a gradually decreases from the toe to the heel of the flexible foot 202 ( Figure 2 When the pull rope 201 is pulled, the flexible foot 202 is greatly curled at the toe, and as the depth of the tooth groove 202a decreases, the curling degree also decreases.

[0065] like Figure 2 As shown, the gecko-like bristles are a directional structure that produces an adhesion effect only when a shear force in a specific direction is applied, and the adhesion force is mainly van der Waals force; the gecko-like bristle array 203 is uneven, and the array density gradually decreases from the toe to the heel of the flexible foot 202, that is, the adhesion area is mainly located in the area near the toe of the flexible foot 202; when the flexible adhesion module 2 contacts the target surface, the flexible foot 202 is in a curled state, and the area near the heel contacts the target surface first. The structural stress is greater than that of other parts, and failure damage is prone to occur. Therefore, setting a sparse gecko-like bristle density near the heel area can reduce the risk of failure and loss, and also facilitate desorption.

[0066] like Figure 1 、 2 As shown, further, the variable stiffness damper 3 includes a piston buffer rod 301, a one-way SMA spring II 302 and a cylinder 303; an adhesive layer is provided at the head end of the piston buffer rod 301, and the adhesive layer is a flexible dry rubber pad 301a, which contacts the target surface and establishes preliminary adhesion during the landing collision process; the tail end of the piston buffer rod 301 is fixedly connected to the tail end of the one-way SMA spring II 302, and the head end of the one-way SMA spring II 302 is fixedly connected to the upper surface of the driving bracket 103, and the piston buffer rod 3 01 passes through the one-way SMA spring II 302 along its axis. At the beginning of the landing collision, the piston buffer rod 301 contacts the target surface, and the one-way SMA spring II 302 tends to be stretched. The cylinder 303 is placed on the upper surface of the driving bracket 103. The one-way SMA spring II 302 is located within the cylinder 303. The tail end of the piston buffer rod 301 is inserted into the cylinder 303. The sleeve 103a of the driving bracket 103 is sleeved on the outer wall of the piston buffer rod 301. By electrically heating the one-way SMA spring II 302, it contracts. When the piston buffer rod 301 contacts the collision target surface, the one-way SMA spring II 302 is stretched. The current flowing through the one-way SMA spring II 302 is adjusted according to the pre-landing altitude. The stiffness of the one-way SMA spring II 302 varies at different temperatures, and the cushioning effect provided by the variable stiffness damper 3 also varies.

[0067] like Figure 2 As shown, the flexible dry adhesive pad 301a is formed by a micro-nano structure array, and the cross-sectional shape of the micro-nano structure is "⊥"-shaped, which can withstand a large normal impact force and produce adhesion, while the tangential force will not produce adhesion.

[0068] like Figure 1 As shown, multiple groups of flexible adhesion modules 2 and driving systems 1 can be arranged around the circumference of the sleeve 103a.

[0069] like Figure 1 、 2 As shown in the figure, the self-loading stable adhesion devices used for on-orbit service of spacecraft are all driven by the smart material shape memory alloy (SMA), with a simple structure and reduced weight of the whole machine.

[0070] like Figures 1 to 3 As shown, the working principle of the device of the present invention is as follows:

[0071] Before landing, the one-way SMA spring I 101 is heated and contracts. Under the action of the pull rope 201 and the lever 104b, the flexible foot 202 curls and moves away from the sleeve 103a. At this time, the projected area of the adhesion surface of the gecko-like bristle structure on the target surface increases, and the orientation of the gecko-like bristles is conducive to establishing adhesion.

[0072] During landing, first, the flexible dry rubber pad 301a contacts the landing surface and establishes initial adhesion under the action of the normal preload (contact force). The one-way SMA spring II 302 is stretched, absorbing the kinetic energy of the mechanism, stabilizing the system and reducing the instantaneous contact force generated by the collision of the flexible foot 202 with the landing surface without damaging the microstructure of the gecko-like bristles. Then, the heel of the flexible foot 202 contacts the target surface. At the same time, as the one-way SMA spring I 101 gradually cools down and its stiffness decreases, the tension provided is less than the restoring tension of the ordinary spring 105. The lever 104b gradually resets, and the flexible foot 202 no longer curls and moves toward the sleeve 103a, generating a tangential force on the gecko-like bristles. Under the combined action of the normal contact force and the tangential force, the adhesion of the gecko-like bristles is enhanced, and the amplitude of the mechanical system is significantly reduced under the action of the variable stiffness damper 3, achieving stable adhesion.

[0073] After landing, when it is necessary to release the adhesion, the one-way SMA spring II 302 is energized and heated to cause it to contract. Since the piston buffer rod 301 is in contact with the target surface and cannot move normally, only the cylinder 303 (with the drive system 1) and the flexible foot 202 can move away from the target surface. At the same time, the one-way SMA spring I 101 is energized and heated to cause it to contract. Under the combined action of the two, the flexible foot 202 can easily release the adhesion from the target surface.

[0074] The above process achieves stable adhesion and easy detachment, which helps the payload equipment to move and transfer on the target surface.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A stable adhesion device for spacecraft on-orbit service, characterized in that: include: A drive system (1), a flexible adhesion module (2) and a variable stiffness damper (3), wherein the drive system (1) is located above the flexible adhesion module (2) and is mounted on the variable stiffness damper (3) located at a central position; the drive system (1) is connected to the flexible adhesion module (2) and is used to drive the flexible adhesion module (2) to move; an interface for an external load device is located on the variable stiffness damper (3); Adhesion layers of different structures are provided on the flexible adhesion module (2) and the variable stiffness damper (3). The adhesion sequence of the different adhesion layers is adjusted according to the structural bearing capacity and adhesion establishment conditions of the different adhesion layers to achieve stable adhesion and smooth detachment with the target surface; The driving system (1) comprises a one-way SMA spring I (101), a ceramic fiber rope (102), a plurality of driving brackets (103), a plurality of lever assemblies (104) and a plurality of common springs (105); the one-way SMA spring I (101) is electrically heated to contract, and the one-way SMA spring I (101) is cooled when the power is turned off, and then extended under the tension of the common spring (105); The driving bracket (103) comprises a sleeve (103a) and a cantilever beam (103c) with a slotted hole (103b); the cantilever beam (103c) is fixedly connected to one end of the sleeve (103a); the sleeve (103a) is connected to the variable stiffness damper (3); a plurality of cantilever beams (103c) are circumferentially distributed around the central axis of the sleeve (103a); and the cantilever beam (103c) is provided with interconnected slotted holes (103b) on four sides thereof. The lever assembly (104) comprises a lever (104b) with a through hole (104a), a slot pin (104c) and a support frame (104d); the power end of the lever (104b) is inserted into the slot hole (103b); the through hole (104a) is located at the power end of the lever (104b); the slot pin (104c) is located at the resistance end of the lever (104b) and is connected to the flexible adhesion module (2); the fulcrum of the lever (104b) is connected to the support frame (104d) and rotates; the support frame (104d) is fixedly connected to the other end of the sleeve (103a); and a plurality of support frames (104d) are circumferentially distributed around the central axis of the sleeve (103a); the flexible adhesion module (2) is also connected to the lever (104b) and the support frame (104d); The ceramic fiber rope (102) passes through the plurality of through holes (104a) in sequence and is connected to both ends of the one-way SMA spring I (101) to form a closed loop surrounding the sleeve (103a); A common spring (105) is installed in each cantilever beam (103c). The common spring (105) is always in a stretched recovery state. The two ends of the common spring (105) are respectively connected to the power end of the lever (104b) and the inner wall of the end of the slot (103b) away from the sleeve (103a); During operation, the one-way SMA spring I (101) contracts after being energized and heated, and the diameter of the closed loop is reduced, thereby pulling the power end of the lever (104b) toward the sleeve (103a); the stiffness of the one-way SMA spring I (101) gradually decreases during the cooling process when the power is turned off, and the one-way SMA spring I (101) gradually extends under the restoring tension of the ordinary spring (105), and at the same time, the power end of the lever (104b) moves in a direction away from the sleeve (103a), and the one-way SMA spring I (101) is energized and heated again to repeat the process, and the power end of the lever (104b) can swing back and forth in the slot (103b), and under the action of the fulcrum, the resistance end of the lever (104b) is driven to swing back and forth, thereby driving the flexible adhesion module (2).

2. The stable adhesion device for on-orbit service of spacecraft according to claim 1, characterized in that: A plurality of the flexible adhesion modules (2) are provided and arranged in a circumferential direction around the variable stiffness damper (3).

3. The stable adhesion device for on-orbit service of a spacecraft according to claim 2, characterized in that: The flexible adhesion module (2) comprises a drawstring (201), a flexible foot (202), and an adhesion layer firmly adhered to the sole of the foot, wherein the adhesion layer is a gecko-like bristle array (203), and the gecko-like bristle array (203) is used to adhere to a target surface; the flexible foot (202) comprises a plurality of tooth grooves (202a) distributed on the dorsum of the foot, and a support rod (202b) and a power rod (202c) connected to the heel; a hole is formed through the tooth groove (202a), and a guide groove (202d) is provided at one end of the power rod (202c); The pull rope (201) passes through the holes on the plurality of tooth grooves (202a) in sequence, and the two ends of the pull rope (201) are respectively connected to the free end of the flexible foot (202) and the power end of the lever (104b). When the pull rope (201) is pulled, the flexible foot (202) bends, thereby achieving the detachment of the gecko-like bristle array (203) from the target surface. The end of the support rod (202b) is inserted into the support frame (104d) and reciprocates within the support frame (104d) along the circumferential radius of the sleeve (103a); The guide groove (202d) cooperates with the groove pin (104c) at the resistance end of the lever (104b) to form a groove pin pair, converting the circular motion of the resistance end of the lever (104b) into linear motion, driving the flexible foot (202) to perform reciprocating motion along the circumferential radius of the sleeve (103a), thereby generating a tangential force on the gecko-like bristle array (203); when the tangential force points toward the sleeve (103a), adhesion occurs; when the tangential force points away from the sleeve (103a), the adhesion is released; under the dual action of the pull rope (201) and the resistance end of the lever (104b), the detachment process of the gecko-like bristle array (203) is achieved more easily.

4. The stable adhesion device for on-orbit service of a spacecraft according to claim 3, characterized in that: The variable stiffness damper (3) comprises a piston buffer rod (301), a one-way SMA spring II (302) and a cylinder (303); an adhesive layer is provided at the head end of the piston buffer rod (301), the adhesive layer being a flexible dry rubber pad (301a), which contacts the target surface during the landing collision process and establishes initial adhesion; The tail end of the piston buffer rod (301) is fixedly connected to the tail end of the one-way SMA spring II (302), and the head end of the one-way SMA spring II (302) is fixedly connected to the upper surface of the driving bracket (103). The piston buffer rod (301) passes through the one-way SMA spring II (302) along the axis of the one-way SMA spring II (302). At the beginning of the landing collision, the piston buffer rod (301) contacts the target surface, and the one-way SMA spring II (302) tends to be stretched. The cylinder (303) is placed on the upper surface of the driving bracket (103), the one-way SMA spring II (302) is located in the cylinder (303), the tail end of the piston buffer rod (301) is inserted into the cylinder (303), and the sleeve (103a) of the driving bracket (103) is sleeved on the outer wall of the piston buffer rod (301); By applying electricity to the one-way SMA spring II (302) and heating it, the one-way SMA spring II (302) is contracted, and when the piston buffer rod (301) contacts the collision target surface, the one-way SMA spring II (302) is stretched; according to the height before landing, the current of the one-way SMA spring II (302) is adjusted, and the stiffness of the one-way SMA spring II (302) is different at different temperatures, and the buffering effect provided by the variable stiffness damper (3) is also different.

5. The stable adhesion device for on-orbit service of a spacecraft according to claim 3, characterized in that: The flexible foot (202) is made of a flexible elastic material; a plurality of tooth grooves (202a) are unevenly distributed on the instep of the flexible foot (202), with different spacings and depths; the depth of the plurality of tooth grooves (202a) gradually decreases from the toe to the heel of the flexible foot (202), and the degree of curling of the flexible foot (202) also gradually decreases when the pull rope (201) is pulled; when the pull rope (201) is pulled, the degree of curling of the flexible foot (202) is large at the toe, and as the depth of the tooth grooves (202a) decreases, the degree of curling also gradually decreases.

6. The stable adhesion device for on-orbit service of a spacecraft according to claim 3, characterized in that: The gecko-like bristles in the gecko-like bristle array (203) are a directional structure. After a shear force in a specific direction is applied, the contact area between the directional structure and the target surface increases, thereby generating an adhesion effect. The gecko-like bristle array (203) is unevenly distributed, and the array density gradually decreases from the toe to the heel of the flexible foot (202), that is, the adhesion area is mainly located in the area near the toe of the flexible foot (202). When the flexible adhesion module (2) contacts the target surface, the flexible foot (202) is in a curled state, and the area near the heel contacts the target surface first. The structural stress is greater than that of other parts, and failure damage is likely to occur. Based on this, a sparse gecko-like bristle density is set in the area near the heel to reduce the risk of failure and loss, and also facilitate desorption.

7. The stable adhesion device for on-orbit service of a spacecraft according to claim 4, characterized in that: The flexible dry adhesive pad (301a) is formed by a micro-nano structure array, the cross-section of the micro-nano structure is in a "⊥" shape, and is used to withstand a large normal impact force and produce an adhesion effect, while a tangential force will not cause the micro-nano structure to produce an adhesion effect.

8. The stable adhesion device for on-orbit service of a spacecraft according to claim 1, characterized in that: The stable adhesion device is driven as a whole by an intelligent material shape memory alloy.

9. A method for operating a stable adhesion device for on-orbit service of a spacecraft according to claim 4, characterized in that: The steps include: Before landing, the one-way SMA spring I (101) is heated and contracts, and under the action of the pull rope (201) and the lever (104b), the flexible foot (202) curls and moves away from the sleeve (103a). At this time, the projected area of the adhesion surface of the gecko-like bristle structure on the target surface increases, and the orientation of the gecko-like bristles is conducive to establishing adhesion; During landing, first, the flexible dry rubber pad (301a) contacts the landing surface and establishes initial adhesion under the action of normal preload, and the one-way SMA spring II (302) is stretched to absorb the kinetic energy of the mechanism, thereby stabilizing the system and reducing the instantaneous contact force generated by the collision between the flexible foot (202) and the landing surface without damaging the microstructure of the gecko-like bristles; thereafter, the heel of the flexible foot (202) contacts the target surface, and at the same time, as the one-way SMA spring I (101) gradually cools down and its stiffness decreases, the tension provided is less than the restoring tension of the ordinary spring (105), the lever (104b) gradually resets, and the flexible foot (202) no longer curls and moves toward the sleeve (103a), generating a tangential force on the gecko-like bristles; under the combined action of the normal contact force and the tangential force, the adhesion of the gecko-like bristles is enhanced, and the amplitude of the mechanical system is significantly reduced under the action of the variable stiffness damper (3), thereby achieving stable adhesion; After landing, when it is necessary to detach from the adhesion, the one-way SMA spring II (302) is electrically heated to cause contraction. The piston buffer rod (301) does not move normally due to contact with the target surface. Only the cylinder (303) and the flexible foot (202) can move away from the target surface. At the same time, the one-way SMA spring I (101) is electrically heated to cause contraction. Under the combined action of the two, the flexible foot (202) can easily detach from the target surface.

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