Connecting mechanism for recovering fixed-wing unmanned aerial vehicle

Abstract

The invention discloses a connecting mechanism for recovering a fixed-wing unmanned aerial vehicle. The connecting mechanism comprises a harpoon landing assisting device and a grating platform. Wherein the harpoon auxiliary landing device is carried on the sub unmanned aerial vehicle and is integrally of a cylindrical structure, and clamping jaws are designed in the circumferential direction. The clamping jaw can be automatically opened and passively retracted under the elastic action of the spring; and meanwhile, the clamping jaw can be controlled by the vertical rod to be recycled. The harpoon landing assisting device of the structure can be inserted into a grid on a grid platform carried on an empty base platform in a matched mode, and the clamping jaws are passively recycled under the action of the edges of grid holes during insertion, so that the harpoon landing assisting device can be inserted into the grid holes; after being inserted, the clamping jaws are automatically unfolded under the elastic force of the springs and are locked with the grating platform. And during unlocking, the jack catches are controlled to retract through the vertical rod. The air-based landing device is simple in structure, low in cost, quicker in locking process, more convenient to produce and machine and more suitable for the air-based landing and releasing process of small and medium-sized unmanned aerial vehicles.

Description

Technical Field

[0001] The present invention relates to the field of aviation, and particularly to an air docking assistance system for mother and son unmanned aerial vehicles. Generally speaking, the present invention aims to provide a new docking mechanism to achieve efficient and safe docking of the son unmanned aerial vehicle with the mother unmanned aerial vehicle in the air. Background Art

[0002] In the field of unmanned aerial vehicle technology, especially in the mother and son unmanned aerial vehicle system, air docking is a complex process involving various special challenges, similar to the problems faced when a helicopter lands on a ship. These challenges specifically include: the impact of the turbulent airflow environment on the control of unmanned aerial vehicles: at high altitudes or under specific meteorological conditions, unmanned aerial vehicles may encounter unstable airflows such as gusts and turbulence, which may lead to abnormal flight responses, increasing the risk of collision or resulting in docking failure; the deviation of the allowable docking point: due to the movement of the mother unmanned aerial vehicle in the air and external environmental factors (such as wind speed, temperature changes, etc.), the safe docking range is constantly changing. The deviation of the docking point increases with the change of external conditions, which may cause the son unmanned aerial vehicle to be unable to dock accurately or even collide with obstacles on the mother unmanned aerial vehicle; the relative speed control problem: during the docking process, the relative speed between the son unmanned aerial vehicle and the mother unmanned aerial vehicle needs to be precisely controlled. If the speed is too high or the direction is inappropriate, it may cause hard contact, resulting in structural damage or equipment damage; the stability after docking: once the docking is completed, if there is no proper locking mechanism, the son unmanned aerial vehicle may slip on the mother unmanned aerial vehicle due to air resistance or other external forces, thus triggering the risk of collision or losing the docking state.

[0003] In summary, the air docking of the mother and son unmanned aerial vehicle system is affected by various factors such as the performance of the unmanned aerial vehicle, environmental conditions, and the accuracy of the control system. To ensure the safety and reliability of docking, it is usually necessary to rely on an auxiliary docking system to assist in achieving this process.

[0004] In view of the above challenges, the air docking of the mother and son unmanned aerial vehicle system also needs to rely on an auxiliary docking system to improve the success rate and safety of docking. The main functions of such a system are as follows:

[0005] 1. Keep the position of the son unmanned aerial vehicle unchanged during the process from touching to fully stable docking, without being affected by the movement of the mother unmanned aerial vehicle;

[0006] 2. Guide the son unmanned aerial vehicle to descend along the correct path to the predetermined docking point;

[0007] 3. Provide a temporary fixing device, which can play a role in mooring the son unmanned aerial vehicle under certain conditions to prevent it from sliding after docking.

[0008] 4. Be able to control the contact lock and achieve the takeoff of the unmanned aerial vehicle.

[0009] In the current market, there is already a design concept of the harpoon grid arresting system used for helicopter landing. This system consists of a "harpoon" installed on the sub-helicopter and a "grid" located on the landing deck. However, most of the existing designs adopt hydraulic drive or pneumatic drive methods. Such drive mechanisms are not only complex in structure and large in weight, but also usually require additional hydraulic or pneumatic systems, increasing the complexity and maintenance cost of the overall system. It is not suitable for direct application in the field of unmanned aerial vehicle (UAV) air-based landing. Summary of the Invention

[0010] Aiming at the existing problems of UAV air-based landing, the present invention is specifically optimized for the aerial docking requirements of mother and sub-UAVs to improve docking efficiency and safety. A connecting mechanism for recovering fixed-wing UAVs is proposed to be applicable to the docking, recovery, and release between fixed-wing UAVs and rotary-wing mother aircrafts, mainly solving the problems of low positioning accuracy in current UAV air-based landing; complex processing and production of UAV air-based landing devices; and difficult control of UAV air-based landing devices.

[0011] The connecting mechanism for recovering fixed-wing UAVs of the present invention includes a harpoon-assisted landing device installed on the sub-UAV and a grid platform installed on the air-based platform.

[0012] The harpoon-assisted landing device is of a cylindrical structure as a whole, and is fixedly connected to the sub-UAV at the top; inside, a coaxial vertical rod, a reset block, and a spring are arranged from top to bottom. At the same time, the harpoon-assisted landing device is equally spaced in the circumferential direction with openings, and claw pieces are designed at the openings. The bottom side of the claw piece has a convex part, and the whole is in a hook shape; the bottom of the claw piece is axially connected to the left and right side walls at the opening to form a rotating pair; at the same time, the outer coated parts of the claw pieces in the circumferential direction are opposite to each other and are located between the bottom of the vertical rod and the top of the reset block.

[0013] Thus, the vertical rod is driven and controlled to move downward by a driving motor installed in the sub-UAV. After the bottom of the vertical rod contacts the convex part of the claw piece, the convex part is pressed down, and at the same time, the bottom of the convex part presses down the reset block; during this process, the spring is compressed, and the claw piece rotates inward through the opening towards the inside of the harpoon-assisted landing device, and the whole is received into the outer cylinder. When the driving motor drives the vertical rod to move upward, the spring is released, and the reset block moves upward; during this process, the top of the reset block cooperates with the convex part of the claw piece to make the claw piece rotate outward through the opening towards the outside of the harpoon-assisted landing device until the claw piece contacts the bottom of the opening, and at this time, the claw piece reaches the maximum opening angle.

[0014] The size of the grid holes on the grid platform is adapted to the harpoon-assisted landing device, and only allows the harpoon-assisted landing device when the claw pieces are completely inside to pass through; after the harpoon-assisted landing device passes through the grid holes, the claw pieces are controlled to rotate outward, so that the outer claws cooperate with the grid platform to realize the fixation between the sub-UAV and the air-based platform.

[0015] The advantages of the present invention are as follows:

[0016] 1. The connecting mechanism for recovering fixed-wing unmanned aerial vehicles (UAVs) of the present invention has a certain anti-interference ability and can cope with the problem of inaccurate kinematic differential positioning caused by natural environment and other reasons. This is because the locking of the claw piece and the grille does not depend on too high precision, and the interaction between the two can make the harpoon automatically slide into the grille hole. In the face of low positioning accuracy, only a larger-sized grille needs to be replaced.

[0017] 2. The connecting mechanism for recovering fixed-wing UAVs of the present invention has high versatility and is convenient for modular design of the airborne platform. The harpoon device is simple to produce and process, and its flange joint with the sub-aircraft can be flexibly changed according to the shape of the sub-aircraft. The airborne platform only needs to adjust the grille size and platform size to adapt to the landing and release of sub-aircrafts of different sizes. This also means that the size of the airborne platform is no longer restricted, and modular design can be better carried out.

[0018] 3. The connecting mechanism for recovering fixed-wing UAVs of the present invention is greatly simplified compared with the existing helicopter harpoon grille assisted landing system on the market, with greatly reduced costs and a faster locking process, making it more convenient for production and processing, and more suitable for the airborne landing and release process of small and medium-sized UAVs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the overall structure of the connecting mechanism for recovering fixed-wing UAVs;

[0020] Figure 2 is a sectional view of the structure of the harpoon in the connecting mechanism for recovering fixed-wing UAVs in the open state;

[0021] Figure 3 is a sectional view of the structure of the harpoon in the connecting mechanism for recovering fixed-wing UAVs in the retracted state;

[0022] Figure 4 is a schematic diagram of the locking of the harpoon and the grille in the connecting mechanism for recovering fixed-wing UAVs.

[0023] In the figure:

[0024] 1 - Harpoon assisted landing device 2 - Grille platform 101 - Vertical rod

[0025] 102 - Outer cylinder 103 - Claw piece 104 - Reset block

[0026] 105 - Spring 102a - Cylindrical channel 102b - Flange structure

[0027] 102c - Blind hole 102d - Rectangular slot DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention will be further described in detail below with reference to the accompanying drawings.

[0029] As Figure 1 shown, the connecting mechanism of the present invention for recovering a fixed-wing unmanned aerial vehicle includes a harpoon-assisted landing device 1 and a grid platform 2, as Figure 1 shown.

[0030] A plurality of the harpoon-assisted landing devices 1 are carried on the sub-unmanned aerial vehicle and are respectively located symmetrically below the front part, the rear part, and the left and right wing bottoms of the unmanned aerial vehicle fuselage.

[0031] As Figure 2 , Figure 3 shown, the harpoon-assisted landing device 1 is composed of a vertical rod 101, an outer cylinder 102, claw pieces 103, a reset block 104, and a spring 105.

[0032] Among them, the outer cylinder 102 serves as the main body of the harpoon-assisted landing device 1 and has a cylindrical structure. A coaxial cylindrical channel 102a is opened axially at the top end, and the bottom end is a conical structure with a cone angle of 60 degrees for mating connection with the grid platform 2. The top surface of the outer cylinder 102 is a flange structure 102b for connecting the sub-unmanned aerial vehicle; the shape of the flange structure 102b can be flexibly adjusted according to the outer surface of the sub-unmanned aerial vehicle at the installation position of the harpoon-assisted landing device 1, so that the flange structure 102b fits the outer surface of the unmanned aerial vehicle and is fixedly connected by bolts to improve the versatility of the device; when the harpoon-assisted landing device 1 located on the wing is installed, the wing skin part at the connection position can be removed so that the flange structure 102b is connected to the internal beam of the wing (at this time, the structural dimensions of the flange should be equal to the removed part of the wing skin) to reduce the load on the wing.

[0033] In the above-mentioned outer cylinder 102, a blind hole 102c is also coaxially opened at the center position of the bottom surface of the cylindrical channel 102a. The bottom end of the blind hole 102c is located near the conical tip of the bottom end of the outer cylinder 102 and is used for arranging the vertical rod 101, the reset block 104, and the spring 105. At the same time, four rectangular slots 102d designed along the circumferential direction of the outer cylinder 102 are circumferentially and equally angularly spaced on the lower side wall of the outer cylinder 102, and the four rectangular slots 102d are all communicated with the blind hole 102c and are respectively used for arranging the four claw pieces 103.

[0034] The vertical rod 101 is coaxially arranged with the outer cylinder 102, and the bottom end is an arc surface and is inserted into the blind hole 102c at the bottom surface of the cylindrical channel 102a. A reset block 104 and a spring 105 are also arranged in the blind hole 102c from top to bottom. Among them, the bottom end of the spring 105 contacts the bottom end of the blind hole 102c, and the top end contacts the bottom surface of the reset block 104. The bottom end of the reset block 104 is designed as a cylindrical structure, and the circumferential cooperation with the side wall of the blind hole 102c realizes the radial positioning of the reset block 104.

[0035] The top end of the above-mentioned vertical rod 101 is connected to the output shaft of the driving motor. The driving motor is installed on the sub-unmanned aerial vehicle, and the vertical rod can be driven to move axially through the driving motor, thereby realizing the compression and release of the spring.

[0036] The claw 103 is a strip-shaped plate structure, and the inner side of the front end has an outward convex part 103a, making the whole in a shape like a fishhook, and the positions of all included angles are rounded; the four claws 103 of this structure are respectively located in four rectangular slots 102d on the side wall of the outer cylinder 102, and the outward convex parts are arranged oppositely, and the front ends of the four claws 103 and the two side walls below the rectangular slot 102d are connected by a rotating shaft and a self-lubricating bearing to form a rotating pair; at the same time, the outward convex parts of the four claws 103 are located between the bottom end of the vertical rod 101 and the top surface of the reset block 104. Then, by rotating the claw 103 around the rotating shaft, the rear part of the claw 103 can enter and exit the outer cylinder 102 through the rectangular slot 102d. At the same time, in order to save space, the rear part of the claw 103 is processed by cutting and is relatively thicker than the front end, so that it can bear sufficient shear force and is designed to be relatively thick.

[0037] Thus, by driving the driving motor to provide a moment for the claw 103 to open, the vertical rod 101 is controlled to move downward. After the bottom end of the vertical rod contacts the convex part of the claw 103, the convex part is pressed down, and at the same time the bottom end of the convex part presses down the reset block; during this process, the spring 105 is compressed, and the claw rotates around the rotating shaft and turns inward into the harpoon auxiliary landing device through the opening, and the whole is received into the inner part of the outer cylinder. At this time, it is the closed state of the claw 103, as Figure 3 shown. When the driving motor drives the vertical rod 101 to move upward, the spring 105 is released, providing a restoring force to move the reset block 104 upward. During this process, the top of the reset block cooperates with the convex parts of the four claws 103 to provide an outward rotation moment for the four claws 103, so that the four claws 103 rotate outward around the rotating shaft to the outside of the outer cylinder 102 until the four claws contact the bottom edge of the corresponding rectangular slot 102d. At this time, the four claws 103 reach the maximum opening angle, that is, the included angle between the inner sides of the four claws and the axis of the outer cylinder 102, and this angle is designed to be 60°. At this time, it is the open state of the claw 103, as Figure 2 shown; and in this state, if an external force acting towards the outer cylinder 102 is applied to the outside of the four claws 103, they will also be passively retracted into the inner part of the outer cylinder 102 through the rectangular slot 102d.

[0038] The upper part of the above-mentioned reset block 104 is in a frustum structure, and the axial section is an isosceles trapezoid. When the harpoon is in the retracted state, the top surface of the reset block 104 fits with the front end face of the claw 103; when the harpoon is opening, the circumferential edge of the top surface of the reset block 104 first contacts the position near the end of the outer convex part at the front end of the claw 103.

[0039] As Figure 1As shown, the grid platform 2 is made of metal and carried on an airborne platform. The grid holes on the grid platform 2 can be in various forms such as circular, square, triangular, rhombic, hexagonal, etc. The size of the grid holes is adapted to the outer cylinder 102, and only allows the outer cylinder 102 when the claw 103 is in the closed state to pass through. At the same time, according to the gap between adjacent grid holes on the grid platform 2 and the installation positions of the four outer cylinders 102 on the sub-unmanned aircraft, the grid platform 2 is designed to ensure that the sub-unmanned aircraft and the airborne platform face the same direction. Thus, after the outer cylinder 102 passes through the grid platform 2, the drive motor controls the four claws 102 to open, and then through the cooperation between the grid platform 2 and the outer cylinder 102 and the cooperation between the four claws 103 and the grid platform 2, the locking between the outer cylinder 102 and the grid platform 2 is realized, as Figure 4 shown.

[0040] The chamfer design at the edge of the grid holes on the above grid platform 2, combined with the conical structure at the bottom end of the outer cylinder 102, facilitates guiding the outer cylinder 102 into the grid holes, enabling the locking between the sub-unmanned aircraft and the airborne platform when there is a speed difference between the two. During the locking process of the two, through the internal structure design of the outer cylinder 102, the claw 103 can pass through the grid holes unidirectionally when the outer cylinder 102 is in the open state, automatically realizing the locking and not falling off; through this design, the sub-aircraft no longer relies on precise positioning and control systems to regulate the opening and closing of the recovery device during the landing process, which also means that compared with the existing auxiliary landing devices on the market, this device has low requirements for positioning and control and has strong wind resistance and the ability to resist other interference factors.

[0041] For the harpoon grid type fixed-wing unmanned aircraft airborne recovery and release device of the present invention, when performing the airborne recovery of the fixed-wing unmanned aircraft, first, the dynamic differential technology is used to locate the unmanned aircraft to be recovered. When it is detected by the dynamic differential technology that the unmanned aircraft is within the docking range (the docking range limit is between the grid plane 2 and one sub-wingspan length higher in the longitudinal height and within the coverage range of the grid platform 2 in the horizontal plane), the flight control and navigation module adjusts the unmanned aircraft to fly at the same speed in the same direction as the airborne platform.

[0042] Then, the air-based platform is controlled to have an upward speed relative to the sub-UAV, so that the four recovery and release devices 1 carried on the sub-UAV are in contact with the grille 2. By reasonably designing the installation positions of the four outer cylinders 102 on the sub-UAV and the gaps between the grille holes on the grille platform 2, it is ensured that the four outer cylinders 102 can be inserted into the four grille holes on the grille platform 2 at the same time. In the initial state, the claw piece 103 is in an open state due to the action of the spring 105 and the reset block 104. With the guidance of the chamfer of the edge of the grille hole, the outer cylinder 102 is inserted into the grille hole. During the process, the edge of the grille hole generates an inward torsional torque on the portion of the claw piece 103 extending out of the outer cylinder 102, so that the claw piece 103 is forced to shrink, the reset block 104 is pressed down, and the spring 105 is in a compressed state. When the outer cylinder 102 passes through the grille hole smoothly, the force generated by the edge of the grille hole on the portion of the claw piece 103 extending out of the outer cylinder 102 disappears, the spring 105 rebounds, and the reset block 104 rises, exerting an outward torsional torque on the claw piece 103, and the claw piece 103 opens and cooperates with the grille platform 2 to achieve the locking between the outer cylinder 102 and the grille platform 2, and the sub-UAV lands successfully.

[0043] During the release of the drone, the driving motor drives the vertical rod 101 to press the inner side of the claw piece 103 downward, giving the claw piece 103 an inward torsional torque, forcing the claw piece 103 to converge inward until the claw piece 103 is entirely located inside the outer tube 102. At this time, the outer tube 102 can pass through the grid holes of the grid platform 2 to release the lock with the grid platform 2. Then the flight control module controls the sub-drone and the air-based platform to generate a vertical speed difference, so that the sub-drone is separated from the air-based platform, and the sub-drone takes off.

Claims

1. A connection mechanism for recovering a fixed-wing UAV, characterized in that: These include a harpoon-assisted landing device mounted on the sub-UAV, and a grid platform mounted on the air-based platform; The harpoon-assisted landing device is a cylindrical structure as a whole, and the top end is connected and fixed to the drone; the inside is provided with coaxial vertical poles, reset blocks and springs from top to bottom; at the same time, openings are evenly spaced in the circumference, and claws are designed at the openings; the side of the bottom end of the claw has an outward convex part, and the whole is in a hook shape; the bottom end of the claw is axially connected with the left and right side walls of the opening to form a revolving pair; at the same time, the outer coating parts of the claws in the circumference are opposite and located between the bottom end of the vertical pole and the top end of the reset block; The driving motor installed in the sub-drone drives the control pole to move downward. After the bottom end of the pole contacts the raised part of the claw piece, the raised part is pressed down. At the same time, the bottom end of the raised part is pressed down and reset quickly. During the process, the spring is compressed, and the claw piece rotates around the rotation axis through the opening toward the inside of the harpoon auxiliary landing device, and the whole is retracted into the outer tube. When the driving motor drives the vertical rod to move upward, the spring is released and the reset block moves upward. During this process, the top of the reset block cooperates with the raised part of the claw piece, so that the claw piece rotates around the rotating shaft through the opening to the outside of the harpoon auxiliary landing device until the claw piece contacts the bottom of the opening, at which time the claw piece reaches the maximum opening angle; The size of the grille holes on the grille platform is adapted to the harpoon-assisted landing device, and the harpoon-assisted landing device is only allowed to pass through when the claws are completely inside; after the harpoon-assisted landing device passes through the grille holes, the claws are controlled to rotate outward so that the outer claws cooperate with the grille platform to achieve fixation between the sub-UAV and the air-based platform.

2. A connection mechanism for recovering a fixed-wing UAV as claimed in claim 1, characterized in that: There are multiple harpoon-assisted landing devices, which are installed in symmetrical positions under the front and rear of the drone fuselage and under the left and right wings; at the same time, it is ensured that the four harpoon-assisted landing devices on the sub-drone can be inserted into the four grille holes on the grille platform at the same time.

3. A connection mechanism for recovering a fixed-wing UAV as claimed in claim 1, characterized in that: When the harpoon-assisted landing device located on the wing is installed, a hole is opened in the wing portion at the connection position so that the top end of the harpoon-assisted landing device is connected to the internal beam of the wing.

4. A connection mechanism for recovering a fixed-wing UAV as claimed in claim 1, characterized in that: The bottom end of the harpoon assisted landing device is a conical structure with a cone angle of 60 degrees; at the same time, the edges of the grille holes are chamfered.

5. A connection mechanism for recovering a fixed-wing UAV as claimed in claim 1, characterized in that: The vertical rod is located in the internal channel of the harpoon auxiliary landing device, and the bottom end of the vertical rod, the reset block and the spring are arranged in the blind hole opened on the bottom surface of the channel for radial positioning.

6. A connection mechanism for recovering a fixed-wing UAV as claimed in claim 1, characterized in that: When the claw piece is at the maximum opening angle, the angle between the inner side of the claw piece and the axis of the outer cylinder is 60°.

7. A connection mechanism for recovering a fixed-wing UAV as claimed in claim 1, characterized in that: The thickness of the rear portion of the claw piece is greater than that of the front portion.

8. A connection mechanism for recovering a fixed-wing UAV as claimed in claim 1, characterized in that: The upper part of the reset block is a truncated cone structure, and the axial cross-section is an isosceles trapezoid. When the claw piece is completely located inside the harpoon assisted landing device, the top surface of the reset block fits against the front end surface of the claw piece; when the claw piece rotates toward the outside of the harpoon assisted landing device, the circumferential edge of the top surface of the reset block first contacts the front end of the claw piece near the end of the convex part.

9. A connection mechanism for recovering a fixed-wing UAV as claimed in claim 1, characterized in that: When performing air-based recovery of fixed-wing UAVs, the UAV to be recovered is first positioned with the aid of dynamic differential technology. When the dynamic differential technology detects that the UAV is within the docking range, the flight control and navigation module adjusts the UAV and the air-based platform to fly in the same direction and at the same speed. Then, the air-based platform is controlled to have an upward speed relative to the sub-UAV, so that the outer tube contacts the grille. In the initial state, the claw is in an open state due to the action of the spring and the reset block. As the harpoon auxiliary landing device is inserted into the grille hole, the edge of the grille hole generates an inward torsional torque on the part of the claw extending out of the outer tube, so that the claw is forced to contract, the reset block is pressed down, and the spring is in a compressed state. When the harpoon-assisted landing device passes through the grille hole, the force generated by the edge of the grille hole on the claw extending out of the harpoon-assisted landing device disappears, the spring rebounds, the reset block rises, and an outward torsional torque is applied to the claw, causing the claw to open. At this time, the harpoon-assisted landing device is locked with the grille platform, and the sub-UAV lands successfully. During the release of the drone, the driving motor drives the vertical rod downward to make the claws converge inward until the claws are completely located inside the harpoon assisted landing device. At this time, the harpoon assisted landing device is unlocked from the grid platform.

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