Electrically controlled push button type docking and locking mechanism based on shape memory alloy

Abstract

This invention relates to the field of spacecraft docking and locking technology, and provides an electrically controlled button-type docking and locking mechanism based on shape memory alloy, which can achieve simple, controllable, and efficient unlocking. This invention combines shape memory alloy with a mechanical button-type docking and locking mechanism, ensuring a large clamping force while focusing on reducing the difficulty of the unlocking operation. The resulting button-type docking and locking mechanism possesses both high clamping force and electrically controlled automatic unlocking, solving the problem of high unlocking difficulty in the spacecraft docking and locking process with button-type locks.

Description

Technical Field

[0001] This invention relates to the field of spacecraft docking and locking technology, specifically to an electrically controlled button-type docking and locking mechanism based on shape memory alloy. Background Technology

[0002] With the development of aerospace technology and the increasing complexity of space missions, space structures are showing a trend towards larger sizes. On-orbit assembly, due to its strong scalability and sustainable upgradeability, has become an important method for constructing large space structures. Constructing large structures through on-orbit assembly involves multiple processes, including the transportation and assembly of modules to be assembled, in which the docking and locking mechanism plays a crucial role. The three common mechanical docking and locking mechanisms are the cone-bar type, the peripheral type, and the claw type, with the cone-bar type being the earliest and most mature technology among the three. The cone-bar type docking and locking mechanism consists of an active docking rod and a passive receiving cone. During docking, the docking rod and the receiving cone collide, guiding the space structure into the capture zone within a certain rendezvous error range.

[0003] Common mechanical locking devices are mainly classified into ball-type, knob-type, and push-button-type according to their locking method. Ball-type locking devices achieve centripetal installation of the docking rod through several balls arranged circumferentially along the receiving cone, and use the displacement of the balls to limit and lock the docking rod. Unlocking only requires applying a pulling force in the back direction, therefore the clamping force is relatively small and reliability is low. Knob-type and push-button-type locking devices, based on the ball-type locking device, add a locking safety mechanism. Unlocking requires rotating or continuously pressing a knob (or push button) at the tail of the receiving cone, thus significantly increasing the locking force of the locking mechanism. This increases the reliability of converting multiple spatial modules into a complete structure after docking, playing a crucial role in subsequent structural attitude adjustment and stability maintenance.

[0004] While existing rotary and button-type docking locking mechanisms possess high docking locking forces, their unlocking process places high demands on the operation of robotic arms. For example, using a button-type docking locker requires the on-orbit robot to continuously apply pressure during spacecraft unlocking, increasing the operational difficulty of on-orbit docking tasks. Furthermore, for large aerospace structures, the unlocking process typically requires rotating or pressing numerous locks. Unlocking a limited number of on-orbit robots one by one is time-consuming and inefficient, further increasing the time complexity of on-orbit docking tasks. Summary of the Invention

[0005] In view of this, the present invention provides an electrically controlled button-type docking locking mechanism based on shape memory alloy, which can achieve simple, controllable and efficient unlocking.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] An electrically controlled button-type docking and locking mechanism based on shape memory alloy includes an active docking mechanism and a passive docking mechanism. A pre-treated shape memory alloy wire is connected to the docking and locking mechanism via an inductor wire. The main body of the active docking mechanism is a guide rod, which is connected to an active connecting plate. One side of the active connecting plate has a through hole for connecting to a tracking satellite. The passive docking mechanism is installed on the target satellite. During the docking process, the active and passive docking mechanisms collide to guide the docking of the space mechanism and achieve locking. When unlocking, an electrically controlled auxiliary device is used to heat the shape memory alloy wire, causing the wire to contract and unlock.

[0008] The passive docking mechanism consists of a button-type locking device as its main body, with an unlocking button at the end. The front end of the locking device connects to the end of the receiving cone. The receiving cone is connected to a U-shaped limiting component with a through hole via a spring. This U-shaped limiting component is assembled with a Z-shaped connector and two L-shaped limiting plates. The through hole in the middle of the front side of the Z-shaped connector, in conjunction with a spring, is used to limit the rigid displacement of the receiving cone. The through hole in the middle of the rear side of the Z-shaped connector is assembled with a threaded connector and connected to the main circular truss of the spacecraft. The Z-shaped connector has four... Four pre-treated shape memory alloy wires pass through the four through holes, with one end knotted and fixed to the Z-shaped connector, and the other end connected to four rope locking devices. The ends of the rope locking devices and the knotted ends of the shape memory alloy wires are connected to wires, which are wound around the main truss and can be connected to the end gripper of the robotic arm to form a path for supplying power to heat the shape memory alloy wires when unlocking. The four rope locking devices are assembled with aluminum pressure plates, which are used to press the end button of the locking device to unlock. Two L-shaped limit plates are used to limit the lateral displacement of the aluminum pressure plate.

[0009] The pretreatment process of the shape memory alloy wire is as follows: at a low temperature, an axial external force is applied to the shape memory alloy wire to deform it, and after the axial external force is unloaded, the shape memory alloy wire will retain the pre-deformation.

[0010] When the active docking mechanism and the passive docking mechanism approach each other, the ball strip at the front end of the guide rod collides with the conical surface of the receiving cone. Guided by the inner surface of the receiving cone, it moves toward the button-type locking device. When the guide rod slides into the locking groove and locks, the docking and locking process is completed.

[0011] When the active docking mechanism and the passive docking mechanism separate, the end gripper of the robotic arm supplies power to the wires, and the four shape memory alloy wires connected to the other end of the wires are heated. When the temperature rises to the phase transition temperature of the shape memory alloy wires, the shape memory alloy wires shrink and deform. The other end of the rope lock moves the aluminum pressure plate towards the locking device. The aluminum pressure plate pushes the unlocking button 8 of the locking device to unlock the active docking mechanism. The end gripper of the on-orbit robotic arm grabs the passive docking mechanism and separates it from the other, thus completing the unlocking process.

[0012] Beneficial effects:

[0013] 1. This invention combines shape memory alloy with a mechanical button-type docking locking mechanism. While ensuring that the mechanism has a large clamping force, it also focuses on the difficulty of unlocking operation. This makes the constructed button-type docking locking mechanism have the characteristics of electronic automatic unlocking while ensuring a large clamping force, thus solving the problem of high unlocking operation difficulty of button-type lockers during spacecraft docking and locking.

[0014] 2. The button-type docking locking mechanism of this invention features electronically controlled automatic unlocking. During the unlocking process, only remote power supply is required from the end gripper of the on-orbit robotic arm; unlocking is no longer dependent on the robotic arm's own operation. This design not only reduces the potential safety risks associated with robotic arm unlocking but also significantly improves the unlocking efficiency of the docking mechanism.

[0015] 3. The button-type docking locking mechanism of the present invention adopts shape memory alloy as the unlocking auxiliary material. Shape memory alloy has the characteristics of small mass and simple mechanical deformation form, so that the cone-type docking mechanism still maintains its characteristics of simple structure, small size and small mass.

[0016] 4. The button-type docking locking mechanism of this invention has a simple and reliable unlocking principle: the elastic potential energy released by the shape memory alloy wire after being heated and contracted by electricity is converted into the kinetic energy of the aluminum pressure plate, thereby pushing the aluminum pressure plate to continuously press the unlocking button. The unlocking design is simple and ingenious, giving full play to the actuation potential of the shape memory alloy wire, and is easy to realize the application of ultra-large-scale docking tasks. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the active mechanism and the passive mechanism docking in an embodiment of the present invention.

[0018] Figure 2 This is an isometric view of the active mechanism in an embodiment of the present invention.

[0019] Figure 3 This is an isometric view of the passive mechanism in an embodiment of the present invention.

[0020] Figure 4 This is a top view of the passive mechanism in an embodiment of the present invention.

[0021] Figure 5 This is a cross-sectional view of the passive mechanism in the embodiment of the present invention.

[0022] In the figure, 1 - active docking mechanism, 2 - guide rod, 3 - threaded hole a, 4 - active connection flat plate, 5 - through hole a, 6 - passive docking structure, 7 - button-type locking device, 8 - locking device unlocking button, 9 - receiving cone, 10 - spring, 11 - "Ji"-shaped limiting part, 12 - Z-shaped connecting part, 13 - L-shaped limiting plate, 14 - threaded connector, 15 - round bar truss, 16 - shape memory alloy wire, 17 - rope locking device, 18 - wire, 19 - end gripper of the robotic arm, 20 - aluminum pressing plate, 21 - through hole b, 22 - through hole c, 23 - bolt c, 24 - nut c, 25 - through hole d, 26 - through hole e, 27 - bolt e, 28 - through hole f, 29 - thread g, 30 - threaded hole g, 31 - through hole h, 32 - bolt h, 33 - nut h. Specific embodiments

[0023] The following combines the accompanying drawings and gives embodiments to describe the present invention in detail.

[0024] The electric control button-type docking and locking mechanism based on shape memory alloy of the present invention includes an active docking mechanism 1 and a passive docking mechanism 6. The schematic diagram when the active mechanism docks with the passive mechanism is as Figure 1 shown.

[0025] The active docking mechanism 1 is installed on the tracking satellite. Specifically, the main body of the active docking mechanism 1 is a guide rod 2. The guide rod 2 is connected to the active connection flat plate 4 through the threaded hole a3. One side of the active connection flat plate 4 is provided with a through hole a5 for connecting with the tracking satellite. Figure 2 This is the isometric view of the active mechanism in the embodiment of the present invention.

[0026] The passive docking mechanism 6 is installed on the target satellite. During the docking process, contact and collision occur between the active docking mechanism 1 and the passive docking mechanism 6, thereby guiding the docking of the space mechanism and achieving locking. When unlocking, an electric control auxiliary device is used to assist in unlocking. Figure 3 This is the isometric view of the passive mechanism in the embodiment of the present invention, Figure 4 This is the top view of the passive mechanism in the embodiment of the present invention, Figure 5This is a cross-sectional view of the passive mechanism in an embodiment of the present invention. Specifically, the main body of the passive docking mechanism 6 is a button-type locking device 7, the end of which is an unlocking button 8. The front end of the locking device 7 is connected to the end of the receiving cone 9. The receiving cone 9 is connected to a U-shaped limiting member 11 with through holes b21 by four springs 10. The U-shaped limiting member 11 has four through holes c22 at both ends, which are assembled with Z-shaped connector 12 and two L-shaped limiting plates 13 by bolts c23 and nuts c24. The through hole d25 in the middle of the front side of the Z-shaped connector 12, in conjunction with the spring 10, is used to limit the rigid displacement of the receiving cone 9. The through hole e26 in the middle of the rear side of the Z-shaped connector is assembled with a threaded connector 14 by bolts e27 and connected to the main circular rod truss 15 of the spacecraft. The left and right sides of the front side of the Z-shaped connector have four through holes f28. A pre-treated shape memory alloy wire 16 passes through the four through holes f28, with one end knotted and fixed to the Z-shaped connector 12, and the other end connected to four rope locking devices 17. The ends of the rope locking devices 17 and the knotted ends of the shape memory alloy wires 16 are respectively connected to wires 18. The wires 18 are wrapped around the main truss 15 and can be connected to the end gripper 19 of the robotic arm to form a passage for powering and heating the shape memory alloy wires 16 when unlocking. The four rope locking devices 17 are assembled with the threaded holes g30 on the aluminum pressure plate 20 through the surface threads g29. The aluminum pressure plate 20 is used to press the end button 8 of the locking device 7 to unlock. The ends of the two L-shaped limiting plates 13 have through holes h31, which are assembled with bolts h32 and nuts h33 to limit the lateral displacement of the aluminum pressure plate 20.

[0027] The pretreatment process of the shape memory alloy wire 16 is as follows: at a low temperature, an axial external force is applied to the shape memory alloy wire to deform it. After unloading the axial external force, the shape memory alloy wire retains the pre-deformation. This process mainly utilizes the shape memory effect of shape memory alloys: shape memory alloys in the austenitic state exhibit a medullary martensite state under low-temperature cooling. After loading and unloading the medullary martensite, its pre-deformation is retained. After being heated again, the pre-deformation is released, and it returns to the initial austenitic state. Specifically, in the mechanism of this invention, the pretreated shape memory alloy wire 16 is connected to the docking and locking mechanism via a wire. When the end gripper 19 of the robotic arm heats the shape memory alloy wire 16, the shape memory alloy wire 16 in the non-medullary martensite state undergoes a phase transformation. During the phase transformation, the pre-strain retained at low temperature is released, and the shape memory alloy wire 16 contracts, thereby driving the aluminum pressure plate 20 to press the unlock button 8 at the end of the locking device 7.

[0028] The docking and locking process of the present invention is as follows: when the active docking mechanism 1 and the passive docking mechanism 6 approach each other, the ball band at the front end of the guide rod 2 collides with the conical surface of the receiving cone 9, and moves towards the button-type locking device 7 under the guidance of the inner surface of the receiving cone 9. The docking and locking process is completed when the guide rod 2 slides into the locking groove and locks.

[0029] The electrically controlled automatic unlocking process of the present invention is as follows: When the active docking mechanism 1 and the passive docking mechanism 6 separate, the end gripper 19 of the robotic arm supplies power to the wire 18, and the four shape memory alloy wires 16 connected to the other end of the wire are energized and heated. When the temperature rises to the phase transition temperature of the shape memory alloy wires 16, the shape memory alloy wires 16 shrink and deform. Since one end of the shape memory alloy wire 16 is knotted and fixed to the Z-shaped connector 12, the other end fixed to the rope locking device 17 drives the aluminum pressure plate 20 to move towards the locking device 7. The aluminum pressure plate pushes the unlocking button 8 of the locking device 7 to unlock the active docking mechanism 1. The end gripper 19 of the on-rail robotic arm grabs the passive docking mechanism 2 and separates it from each other, thus completing the unlocking process. In the above unlocking process, the elastic potential energy released by the shape memory alloy wires 16 after being energized and heated and contracted is converted into the kinetic energy of the aluminum pressure plate 20, thereby pushing the aluminum pressure plate 20 to continuously press the unlocking button 8, realizing the electrically controlled automatic unlocking process of the button-type locking device 7.

[0030] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An electrically controlled push-button docking and locking mechanism based on shape memory alloy, comprising an active docking mechanism and a passive docking mechanism, characterized in that, The pre-treated shape memory alloy wire is connected to the docking and locking mechanism via a wire. The main body of the active docking mechanism is a guide rod, which is connected to the active connecting plate. One side of the active connecting plate has a through hole for connecting to the tracking satellite. The passive docking mechanism is installed on the target satellite. During the docking process, the active docking mechanism and the passive docking mechanism make contact and collision, thereby guiding the docking of the space mechanism and achieving locking. When unlocking, the shape memory alloy wire is heated by an electronic control auxiliary device, causing the shape memory alloy wire to contract and thus unlock. The passive docking mechanism consists of a button-type locking device as its main body, with an unlocking button at the end. The front end of the locking device connects to the end of the receiving cone. The receiving cone is connected to a U-shaped limiting component with through holes via a spring. This U-shaped limiting component is assembled with a Z-shaped connector and two L-shaped limiting plates. The through hole in the middle of the front side of the Z-shaped connector, in conjunction with a spring, restricts the rigid displacement of the receiving cone. The through hole in the middle of the rear side of the Z-shaped connector is assembled with a threaded connector and connected to the main circular truss of the spacecraft. The Z-shaped connector has four through holes on its front left and right sides. Four pre-treated shape memory alloy wires pass through these four through holes, with one end knotted and fixed to the Z-shaped connector. On the connecting piece, four rope locking devices are connected to the other end; the ends of the rope locking devices and the knotted ends of the shape memory alloy wires are respectively connected to wires, which are wound around the main truss and can be connected to the end gripper of the robotic arm to form a path for supplying power to heat the shape memory alloy wires when unlocking; the four rope locking devices are assembled with aluminum pressure plates, which are used to press the end button of the locking device to unlock; two L-shaped limit plates are used to limit the lateral displacement of the aluminum pressure plate.

2. The mechanism as described in claim 1, characterized in that, The pretreatment process of the shape memory alloy wire is as follows: At low temperature, an axial external force is applied to the shape memory alloy wire to deform it. After the axial external force is unloaded, the shape memory alloy wire will retain the pre-deformation.

3. The mechanism as described in claim 1, characterized in that, When the active docking mechanism and the passive docking mechanism approach each other, the ball strip at the front end of the guide rod collides with the conical surface of the receiving cone. Guided by the inner surface of the receiving cone, it moves toward the button-type locking device. When the guide rod slides into the locking groove and locks, the docking and locking process is completed.

4. The mechanism as described in claim 1 or 3, characterized in that, When the active docking mechanism and the passive docking mechanism are separated, the end gripper of the robotic arm supplies power to the wires, and the four shape memory alloy wires connected to the other end of the wires are heated by electricity. When the temperature rises to the phase transition temperature of the shape memory alloy wires, the shape memory alloy wires shrink and deform. The other end of the rope locker drives the aluminum pressure plate to move towards the locking device. The aluminum pressure plate pushes the unlocking button (8) of the locking device to unlock the active docking mechanism. The end gripper of the on-orbit robotic arm grabs the passive docking mechanism to separate them from each other, thus completing the unlocking process.

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