A space capture mechanism

Abstract

The present invention discloses a space capture mechanism, which relates to the field of aerospace technology. It includes an end effector. The end effector includes a damping element and a plurality of viscous elements. The viscous elements are arranged circumferentially around the damping element and are installed at the tip of the end effector. The viscous element includes a top seat, a disc, and a plurality of laminated plates. Both sides of the top seat are respectively connected to a clamping structure and the disc. The laminated plates are rotatably connected to the side of the disc away from the top seat, and a group of patches are installed on both the upper and lower sides of the laminated plates. The patch includes a shape memory alloy sheet and a heating film stacked up and down. A gecko dry adhesive layer is also provided on the lower end surface of the laminated plate. This space capture mechanism has a simple structure, convenient driving, stable clamping, and low power consumption.

Description

Technical Field

[0001] The present invention relates to the field of aerospace technology, and more particularly to a space capture mechanism. Background Art

[0002] With the development of aerospace technology, machines such as drones and robots are increasingly used for remote work in current space missions. For on-orbit targets, if we need to carry out some mission work, the prerequisite for carrying out these works is to capture the target first, and the machine that plays this role is the space capture mechanism.

[0003] Shape memory effect refers to the phenomenon that a solid material with a certain initial shape deforms under the action of an external force, and the deformation does not completely recover after the external force is removed. After being stimulated by heat energy, light energy, electrical energy or chemical reagents, it returns to the initial shape. Alloys composed of some metal elements have shape memory effects, so they are called Shape Memory Alloys (SMA). SMA actuators have been widely used because of their advantages such as large recoverable strain, large driving force, and simple triggering method. SMA-driven intelligent structures have monostable structures or bistable structures. The characteristic of the monostable structure is that the deformation of the structure needs to be maintained by continuous temperature excitation, which does not conform to the concept of energy conservation and environmental protection, and the preparation is difficult. The bistable composite laminate is used as the base structure and the SMA-driven sheet actuator to design and prepare a controllable bistable deformable structure, which can jump from one stable state to another after short-term excitation, and is a good controllable, energy-saving and efficient driving method.

[0004] The adhesion principle of geckos is very rare. Its feet are covered with nanoscale bristles, which allows the soles of the feet to have the largest contact area with the object surface. Van der Waals forces are generated between the bristles and the object surface, thus generating an adsorption effect. This adhesion effect does not change with the roughness and chemical composition of the object surface. Therefore, the gecko adhesive made based on this principle is an excellent adhesion material. Compared with traditional grasping methods (such as suction and magnets), this adhesive has several advantages, such as low power consumption and applicability to more materials. In addition, the microstructured adhesive can be used in unique environments, such as space. Due to the vacuum in space and the accompanying exhaust problems, suction and pressure-sensitive adhesives become useless.

[0005] The targets of the space capture mechanism are usually cooperative targets or non-cooperative targets. Cooperative targets usually have devices for cooperating with capture, so they are very easy to capture. However, the proportion of such targets in aviation missions is relatively small, and most mission targets are non-cooperative targets.

[0006] In most of the existing space capture mechanisms, mechanical structures are adopted, which are driven by motors. They have complex structures, are prone to failures, and are large in size and weight, seriously affecting the working stability and increasing the transportation cost at the same time. For example, a space capture robot and its capture mechanism device disclosed in the patent with the patent number CN202011270231.6 is composed of a complex space capture mechanism formed by a support component, a sliding plate, a transmission component, etc. The structure is very complex and the stability is not certain. At the same time, the patent with the patent number CN201710331076.6 proposes an underactuated space capture mechanism and a capture method, which sets two motors to drive the capture, with a large weight and a short endurance. Summary of the Invention

[0007] The purpose of the present invention is to provide a space capture mechanism to solve the problems existing in the above-mentioned prior art, with a simple structure, convenient driving, stable clamping and low power consumption.

[0008] To achieve the above purpose, the present invention provides the following solutions:

[0009] The present invention provides a space capture mechanism, including an end effector. The end effector includes a damping element and a plurality of viscous elements. The viscous elements are circumferentially arranged around the damping element and are installed at the tip of the end effector. The viscous element includes a top seat, a disc and a plurality of laminated plates. The two sides of the top seat are respectively connected to a clamping structure and the disc. The laminated plates are rotatably connected to the side of the disc away from the top seat, and a set of patches is installed on both the upper and lower sides of the laminated plates. The patch includes a shape memory alloy sheet and a heating film stacked up and down. A gecko dry adhesive layer is also provided on the lower end surface of the laminated plate.

[0010] Preferably, each set of the patches is two, and the two patches in the same group are symmetrically arranged, and the patches on the same laminated plate are arranged in a cross shape.

[0011] Preferably, the patch is fixed on the laminated plate by a high-temperature adhesive.

[0012] Preferably, the heating film is a polyimide heating film.

[0013] Preferably, round holes are provided on both the top seat and the disc, and the round holes are used for wires to pass through.

[0014] Preferably, there are three laminated plates, and the three laminated plates are evenly distributed around the center of the disc. The laminated plate is a composite material plate.

[0015] Preferably, there are four viscous elements, and the four viscous elements are all arranged towards the damping element.

[0016] Preferably, the gecko dry adhesive layer is made of gecko adhesive.

[0017] Preferably, the damping element includes a housing, a contact circular pad, a piston assembly, a sealing ring, a bearing retainer ring, and a magnetorheological fluid region. One side of the contact circular pad is fixed to one end of the piston assembly. The other end of the piston assembly extends into the housing and forms the magnetorheological fluid region between the inner bottom surface of the housing. The bearing retainer ring is provided at one end of the housing close to the contact circular pad. The bearing retainer ring is located on the outer periphery of the piston assembly. The sealing ring is located on the side of the bearing retainer ring away from the contact circular pad.

[0018] Preferably, the damping element further includes a first-end connector, and the first-end connector is provided with a hole groove for connecting a wire.

[0019] The present invention has achieved the following technical effects compared with the prior art:

[0020] The space capture mechanism provided by the present invention, the end effector includes a damping element and a plurality of viscous elements. The viscous elements are circumferentially arranged around the damping element and are installed at the tip of the end effector. The damping element can shock-absorb and buffer the capture target, enabling it to better contact the viscous elements. The viscous elements include a top seat, a disc, and a plurality of laminated plates. The two sides of the top seat are respectively connected to the clamping structure and the disc. The laminated plates are rotatably connected to the side of the disc away from the top seat, improving the overall application range. A set of patches are installed on both the upper and lower sides of the laminated plates. The patches include shape memory alloy sheets and heating films stacked up and down. Using the shape memory alloy sheets as actuators, the bistable structure of the laminated plates is utilized, making the structure simple and the driving convenient, reducing the energy consumption of the system, and increasing the battery life. A gecko dry adhesive layer is also provided on the lower end surface of the laminated plate. Since the adhesion principle of the gecko dry adhesive layer can eliminate the change in adhesion force caused by the roughness of the capture target surface and the change in chemical composition, the present invention has a large application range, can capture various types of targets, and at the same time has high stability and reliability. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 is a schematic structural diagram of the end effector in the present invention;

[0023] Figure 2 is a schematic structural diagram of the viscous element at an angle in the present invention;

[0024] Figure 3 It is a schematic structural diagram of the adhesive element in another angle in the present invention;

[0025] Figure 4 It is the front view of the laminate in the present invention;

[0026] Figure 5 It is the top view of the laminate in the present invention;

[0027] Figure 6 It is a schematic diagram of the laminate when the present invention is in the released target state;

[0028] Figure 7 It is a schematic external structure diagram of the damping element in the present invention;

[0029] Figure 8 It is a schematic internal structure diagram of the damping element in the present invention;

[0030] Figure 9 It is a schematic diagram of the process of using the space capture mechanism provided by the present invention;

[0031] In the figure: 1 - adhesive element, 2 - damping element, 3 - laminate, 4 - disc, 5 - top seat, 6 - patch, 7 - SMA driving sheet, 8 - polyimide heating film, 9 - gecko dry adhesive layer, 10 - sealing ring, 11 - contact circular pad, 12 - magnetorheological fluid area, 13 - bearing retainer, 14 - piston assembly, 15 - outer shell. Detailed implementation manners

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] The purpose of the present invention is to provide a space capture mechanism to solve the technical problems of the existing space capture devices with complex structures, unstable clamping, and high energy consumption.

[0034] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0035] As Figures 1-9As shown in the figure, this embodiment provides a space capture mechanism, including an end effector. The end effector includes a damping element 2 and a plurality of viscous elements 1. The viscous elements 1 are arranged circumferentially around the damping element 2 and are installed at the tip of the end effector. The damping element 2 can shock-absorb and buffer the captured target, enabling it to better contact the viscous elements 1. The viscous element 1 includes a top seat 5, a disc 4, and a plurality of laminates 3. The two sides of the top seat 5 are respectively connected to the clamping structure and the disc 4. The laminates 3 are rotatably connected to the side of the disc 4 away from the top seat 5, improving the overall applicable range. A group of patches 6 are installed on both the upper and lower sides of the laminate 3. The patch 6 includes a shape memory alloy sheet and a heating film stacked up and down. Using the shape memory alloy sheet (i.e., the SMA driving sheet 7) as a driver, taking advantage of the bistable structure of the laminate 3, makes the structure simple and the driving convenient, reduces the energy consumption of the system, and improves the battery life. A gecko dry adhesive layer 9 is also provided on the lower end surface of the laminate 3. Since the adhesion principle of the gecko dry adhesive layer 9 can eliminate the change in adhesion force caused by the roughness of the surface of the captured target and the change in chemical composition, the present invention has a large application range, can capture various types of targets, and at the same time has high stability and reliability.

[0036] Specifically, each group of patches 6 is two, and the two patches 6 within the same group are symmetrically arranged, and the patches 6 located on the same laminate 3 are arranged in a cross shape. The deformation of the laminate 3 has two local minimum energy potentials. After applying a load, it will jump into a kind of cylindrical shell and can still maintain in this steady state after the load is removed. Among the patches 6 on the same laminate 3, the patch 6 located on the lower side is responsible for the capture function of the viscous element 1, and the patch 6 located on the upper side is responsible for the release function of the viscous element 1.

[0037] The patch 6 is fixed on the laminate 3 through a high-temperature adhesive, that is, the patch 6 is adhered to the laminate 3 by an adhesive that cures at room temperature and is used at medium to high temperatures. The heating film is a polyimide heating film 8. When an electric current is passed through the polyimide heating film 8, it can control the heating of the SMA driving sheet 7 to make the SMA driving sheet 7 contract.

[0038] Both the top seat 5 and the disc 4 are provided with round holes for wires to pass through.

[0039] There are three laminates 3, and the three laminates 3 are evenly distributed around the center of the disc 4. The laminate 3 is a composite material plate, and the laminate 3 is an asymmetric laminated plate.

[0040] There are four viscous elements 1, and the four viscous elements 1 are all arranged towards the damping element 2.

[0041] The gecko adhesive layer 9 is made of gecko adhesive. The adhesion element 1 can imitate the principle of gecko adhesion. The steady-state jump of the laminate 3 increases the contact area between the gecko adhesive and the capture target. The gecko adhesive is shear-loaded, and the van der Waals force between the gecko adhesive and the capture target increases, generating viscosity. By switching between two steady states, it assists the end effector in capturing or releasing.

[0042] The damping element 2 includes a housing 15, a contact circular pad 11, a piston assembly 14, a sealing ring 10, a bearing retainer 13, and a magnetorheological fluid region 12. One side of the contact circular pad 11 is fixed to one end of the piston assembly 14. The other end of the piston assembly 14 extends into the housing 15 and forms a magnetorheological fluid region 12 with the inner bottom surface of the housing 15. A bearing retainer 13 is provided at one end of the housing 15 close to the contact circular pad 11. The bearing retainer 13 is located on the outer periphery of the piston assembly 14, and the sealing ring 10 is located on the side of the bearing retainer 13 away from the contact circular pad 11. When the contact circular pad 11 is about to collide with the capture target, the control system turns on the current. The magnetic fluid in the magnetorheological fluid region 12 can generate a field-related yield stress under the action of an external magnetic field or an electric arc, so that the energy generated by the collision is absorbed, achieving a buffering effect. The magnetic fluid is composed of magnetizable particles and a liquid base oil, preferably silicone oil.

[0043] The damping element 2 further includes a head connector, and the head connector is provided with a hole groove for connecting a wire.

[0044] Before performing the capture, first, the space capture mechanism in this embodiment needs to approach the capture target under the action of a thruster, and at the same time adjust its own attitude so that the end effector is facing the capture target. The end effector is started to fly with the target object, and at the same time the attitude angle is adjusted to achieve synchronous rolling.

[0045] The capture and release processes are as follows:

[0046] After the space capture mechanism is close to the surface of the target object, the polyimide heating film 8 located below the laminate 3 is controlled by current to release heat, thereby heating the SMA drive sheet 7 located below the laminate 3. The SMA drive sheet 7 shrinks when heated, driving the laminate 3 to jump, so that the laminate 3 bends. The contact area between the gecko adhesive layer 9 attached to the lower surface of the laminate 3 and the capture target increases significantly, and is tangentially loaded to generate adhesion, and the target is successfully captured.

[0047] If the target needs to be released, the polyimide heating film 8 above the laminate 3 is controlled by current to release heat, thereby heating the SMA drive sheet 7 located below the laminate 3. After the SMA drive sheet 7 shrinks when heated, it will drive the reverse jump of the laminate 3, and the elastic potential energy stored in the laminate 3 will cause the laminate 3 to return to its original position. The shear loading state of the gecko adhesive is removed, and after the end effector is released, the capture target can be easily released.

[0048] In this specification, specific examples are used to illustrate the principles and implementation manners of the present invention. The description of the above embodiments is only for helping to understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A spatial capture mechanism, including an end effector, characterized in that: The end effector includes a damping element and a plurality of viscous elements. The viscous elements are circumferentially arranged around the damping element and are installed at the tip of the end effector. The viscous element includes a top seat, a disc, and a plurality of laminates. Both sides of the top seat are respectively connected to a clamping structure and the disc. The laminates are rotatably connected to the side of the disc away from the top seat, and a set of patches is installed on both the upper and lower sides of the laminate. The patch includes a shape memory alloy sheet and a heating film stacked up and down. A gecko glue layer is further provided on the lower end surface of the laminate; Each set of the patches is two, and the two patches in the same group are symmetrically arranged. The patches located on the same laminate are arranged in a cross; The damping element includes a housing, a contact circular pad, a piston assembly, a sealing ring, a bearing retainer, and a magnetorheological fluid region. One side of the contact circular pad is fixed to one end of the piston assembly. The other end of the piston assembly extends into the housing and forms the magnetorheological fluid region with the inner bottom surface of the housing. The bearing retainer is provided at one end of the housing close to the contact circular pad. The bearing retainer is located on the outer periphery of the piston assembly. The sealing ring is located on the side of the bearing retainer away from the contact circular pad.

2. The spatial capture mechanism according to claim 1, wherein: The patch is fixed on the laminate by a high-temperature adhesive.

3. The space capture mechanism according to claim 1, characterized in that: The heating film is a polyimide heating film.

4. The space capture mechanism according to claim 1, wherein: Round holes are provided on both the top seat and the disc, and the round holes are used for wires to pass through.

5. The spatial capture mechanism according to claim 1, characterized in that: There are three laminates, and the three laminates are evenly distributed around the center of the disc. The laminate is a composite material plate.

6. The space capture mechanism according to claim 1, characterized in that: There are four viscous elements, and the four viscous elements are all arranged towards the damping element.

7. The space capture mechanism according to claim 1, characterized in that: The gecko glue layer is made of gecko adhesive.

8. The space capture mechanism according to claim 1, characterized in that: The damping element further includes a head connector, and a hole groove for connecting a wire is provided on the head connector.

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