Extended-range unmanned aerial vehicle air refueling system

Abstract

The invention relates to the technical field of unmanned aerial vehicle air refueling, in particular to an extended-range unmanned aerial vehicle air refueling system which adopts a front-back high-low staggered refueling mode, a foldable and unfoldable refueling and oil receiving mechanism, a magnetic attraction auxiliary refueling pipe and an oil receiving pipe to be in butt joint, the safety and stability of an unmanned aerial vehicle are improved, and the refueling difficulty is reduced. Comprising an oiling machine, an oil bin, an oil receiving machine and an oil tank, the oiling machine is provided with an oiling mechanism, the oiling mechanism is provided with the oiling nozzle, the outer wall of the oiling nozzle is sleeved with the annular electromagnet, the oil receiving machine is provided with an oil receiving mechanism, the oil receiving mechanism is provided with the oil receiving nozzle, the electric push rod is installed on the oil receiving nozzle, and the annular positioning ring is arranged at the output end of the electric push rod. The positioning ring is matched with the positioning boss of the annular electromagnet, the annular electromagnet is electrified to attract the positioning ring, and the electric push rod contracts to enable the oil nipple and the oil receiving nipple to be in butt joint.

Description

Technical Field

[0001] The present invention relates to the technical field of aerial refueling of unmanned aerial vehicles, and in particular to an extended-range unmanned aerial vehicle aerial refueling system. Background Art

[0002] Extended-range agricultural drones are rotorcraft drones with batteries and engines, especially multi-rotor drones. Compared with pure electric drones, extended-range drones have longer endurance, so they can carry larger medicine boxes for spraying, and can also fly to more remote plots for spraying. Therefore, the application of extended-range drones is becoming more and more extensive.

[0003] However, since the load capacity of rotorcraft UAVs is limited, the amount of fuel they can carry is also limited. Therefore, if the extended-range UAV has the ability to refuel in the air, its flight endurance can be further extended.

[0004] A variety of UAV aerial refueling systems and methods have been proposed in the prior art. For example, a Chinese invention patent with publication number "CN114897984A" proposes a method for visually aligning a UAV autonomous aerial refueling refueling probe with a refueling cone sleeve.

[0005] The structures and arrangements of the refueling pipe and refueling cone of the refueling UAV and the refueling pipe of the receiving UAV in the prior art all imitate the aerial refueling system of manned aircraft. For example, the Chinese invention patent with publication number "CN115743573A" proposes a UAV refueling assembly and a UAV hard oil pipe docking assembly.

[0006] Since the multi-rotor wings of the refueling aircraft and the receiving aircraft will generate strong downward airflows, these airflows cause serious disturbances and interference to the refueling pipe, the refueling cone and the receiving pipe. In the prior art, the receiving pipe is usually designed to be very long so that it can extend laterally beyond the influence range of the rotor. Although this can reduce the impact of the airflow, it also makes it difficult for the multi-rotor drone to maintain balance, resulting in difficulty in refueling. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides an extended-range UAV aerial refueling system that adopts a front-to-back height-staggered refueling method, a foldable and unfoldable refueling and refueling mechanism, and a magnetic suction-assisted refueling pipe and a refueling pipe docking to improve the safety and stability of the UAV and reduce the difficulty of refueling.

[0008] The invention discloses an extended-range UAV aerial refueling system, comprising a refueling machine, an oil bunker, a refueling receiving machine and a fuel tank, wherein the refueling machine is provided with an oil bunker for carrying fuel, and the refueling receiving machine is provided with a fuel tank for supplying fuel to the engine, and both the refueling machine and the refueling receiving machine are multi-rotor UAVs; the invention also comprises a refueling nozzle, an annular electromagnet, a refueling nozzle, an electric push rod and a positioning ring, wherein the refueling machine is provided with a refueling mechanism which is folded in the middle and lower part of the belly of the machine and can be extended toward the rear of the tail of the machine, the input end of the refueling mechanism is connected to the oil bunker, and the output end of the refueling mechanism is provided with a refueling nozzle, and after the refueling mechanism is extended, the refueling nozzle faces downward, and an annular electromagnet is mounted on the outer wall of the refueling nozzle, and an annular positioning convex is arranged on the end face of the annular electromagnet facing the refueling nozzle. The receiving aircraft is provided with a refueling mechanism which is folded at the middle and lower part of the belly and can be extended to the upper part of the nose. The output end of the refueling mechanism is connected to the fuel tank, the input end of the refueling mechanism is provided with a refueling nozzle, an electric push rod is installed on the outer wall of the refueling nozzle, an annular positioning ring is provided on the output end of the electric push rod, and the concentric rings of the positioning ring are arranged outside the refueling nozzle. The positioning ring matches the positioning boss of the annular electromagnet. The annular electromagnet is energized to adsorb the positioning ring, and the electric push rod contracts to make the refueling nozzle and the refueling nozzle dock. When aerial refueling is needed, the refueling mechanism of the receiving aircraft is extended so that the refueling nozzle is located at the upper part of the nose of the receiving aircraft, which reduces the leverage of the refueling mechanism and makes it easier for the receiving aircraft to keep balance and refuel. The aircraft flies to the front upper part of the receiving aircraft, and the refueling mechanism of the tanker extends, so that the refueling nozzle is at the rear lower part of the tanker. The tanker and the receiving aircraft remain relatively stable. The tanker and the receiving aircraft can fly synchronously or hover. The speed, height and angle of the receiving aircraft are adjusted to make the positioning ring and the annular electromagnet close to each other. The annular electromagnet is energized to generate magnetism, so that the annular electromagnet and the positioning ring can actively adsorb and dock when they are close to a certain distance, so that the positioning protrusion of the annular electromagnet is inserted into the positioning ring. At this time, the refueling nozzle and the receiving nozzle are concentrically aligned, and the electric push rod is contracted, so that the positioning ring pulls the refueling nozzle toward the receiving nozzle through the annular electromagnet, so that the receiving nozzle The refueling mechanism and the refueling receiving mechanism are folded to the lower middle part of the belly of the refueling machine and the refueling receiving machine respectively. Compared with the prior art, this structural mode will not affect the flight and operation of the refueling machine and the refueling receiving machine, and the overall structure is more compact and has no protrusion, and has better balance, which greatly reduces the influence of the rotor airflow on the refueling pipe, and assists the refueling pipe and the refueling receiving pipe to dock by magnetic attraction, thereby reducing the difficulty of refueling.

[0009] Preferably, the refueling mechanism includes a tilting motor 1, a refueling hard pipe and an elastic oil pipe. The tilting motor 1 is installed at the lower part of the tail of the refueling machine. The output shaft of the tilting motor 1 is connected to the inner end of the refueling hard pipe through a clamp. The inner end of the refueling hard pipe is connected to the oil tank through a hose. The oil tank is provided with an oil pump for supplying oil to the refueling hard pipe. The tilting motor 1 drives the refueling hard pipe to be stored in the middle and lower part of the belly of the refueling machine or to extend out of the rear part of the tail of the refueling machine and extend out of the coverage range of the rotor. An elastic oil pipe is arranged at the outer end of the refueling hard pipe, and a refueling nozzle and an annular electromagnet are installed on the output end of the elastic oil pipe. When the refueling hard pipe extends out of the rear part of the tail of the refueling machine, the elastic oil pipe faces downward; in the non-refueling state, the tilting motor 1 drives the refueling hard pipe to be stored in the middle and lower part of the belly of the refueling machine or to extend out of the rear part of the tail of the refueling machine and extend out of the coverage range of the rotor. The dynamic refueling rigid pipe and elastic oil pipe are folded horizontally and stored in the lower middle part of the belly of the tanker, so that the overall structure of the tanker is compact without protrusions, which makes it easier to maintain flight stability. In the refueling state, the flip motor drives the refueling rigid pipe and the elastic oil pipe to rotate, so that the refueling rigid pipe and the elastic oil pipe are flipped to the rear of the tail of the tanker. Since the refueling rigid pipe is located between the two rotors at the center line of the tanker, it can minimize the impact of airflow. The elastic oil pipe faces downward, which makes it convenient to maintain a certain height difference between the tanker and the receiving aircraft, and can reduce the possibility of collision during refueling. During refueling, the oil pump in the oil tank transports oil to the receiving mechanism of the receiving aircraft through the hose, refueling rigid pipe and elastic oil pipe.

[0010] Preferably, it also includes a spring, which is sleeved on the elastic oil pipe and strengthens the elasticity of the elastic oil pipe; the spring is sleeved on the elastic oil pipe, so that the elastic oil pipe is less shaken when subjected to wind and airflow, thereby reducing the difficulty of docking during refueling.

[0011] Preferably, it also includes a tail group, and the tail group is arranged on the outer end of the refueling rigid pipe, and the tail group is provided with multiple wing surfaces; by arranging the tail group on the outer end of the refueling rigid pipe, when the tanker and the receiving aircraft are refueling in a flight state, horizontal airflow acts on the tail group, which has the effect of stabilizing the refueling rigid pipe.

[0012] Preferably, the oil receiving mechanism includes a second flip motor, an active arm, a driven arm, a pull rod and an oil receiving pipe. The second flip motor is installed in the middle and upper part of the nose of the oil receiving machine. The output end of the second flip motor is fixedly connected to one end of the active arm, and the other end of the active arm is rotatably connected to one end of the driven arm. One end of the driven arm is also rotatably connected to one end of the pull rod, and the other end of the pull rod is rotatably connected to the middle part of the nose of the oil receiving machine. The oil receiving pipe is installed on the driven arm, and the input end of the oil receiving pipe is connected to the oil tank through a hose, and the oil receiving nozzle is installed on the output end of the oil receiving pipe. When the second flip motor drives the active arm to rotate toward the lower part of the nose of the oil receiving machine, the supporting effect of the pull rod causes the driven arm and the oil receiving pipe to be horizontally folded and stored below the middle part of the belly of the oil receiving machine. When the upper part of the head of the oil machine rotates, the pulling action of the tie rod makes the driven arm and the oil receiving pipe extend vertically to the top of the head of the oil machine; the active arm, the driven arm and the tie rod form a connecting rod structure, and the positions of the output shaft A of the second flip motor, the connection point B of the tie rod and the oil machine, the connection point C of the active arm and the driven arm, and the connection point D of the driven arm and the tie rod are optimized, so that A is located above and behind B, and the circular motion trajectory of D is located inside the circular motion trajectory of C, so that when the second flip motor drives the active arm to move from vertical upward to vertical downward, the distance between C and B gradually decreases, and the distance between D and A gradually increases, so as to realize the conversion of the pull rod from pulling action to supporting action on the driven arm, and only one power source is needed for the two actions, thereby simplifying the structure and having good practicality.

[0013] Preferably, it also includes a liquid level sensor installed on the fuel tank, the liquid level sensor detects the oil level in the fuel tank, and the liquid level sensor is electrically connected to the control system of the receiving aircraft; when the liquid level sensor detects that the oil in the fuel tank has reached a low level, the control system sends a signal that refueling is required, and starts returning for refueling or performing aerial refueling; when the liquid level sensor detects that the oil in the fuel tank has reached a high level, the control system sends a signal to stop refueling, thereby improving the degree of automation.

[0014] Preferably, a one-way valve is also included. An oil inlet pipe is arranged on the oil inlet of the oil tank. The oil inlet pipe is connected to the oil receiving pipe through a hose. A one-way valve is arranged on the oil inlet pipe. The one-way valve blocks the backflow of oil in the oil tank. By setting the one-way valve, a siphon phenomenon causing backflow and leakage of oil can be avoided when the boom and the oil receiving pipe are folded and stored under the belly of the receiving machine.

[0015] Preferably, it also includes a vacuum pump, which is installed on the fuel tank. When refueling, the vacuum pump is started to pump the upper cavity of the fuel tank into a low-pressure state; the vacuum pump draws air to form a low-pressure state in the upper cavity of the fuel tank, so that the fuel can be quickly input into the fuel tank, thereby increasing the refueling speed.

[0016] Preferably, it also includes a raised portion, wherein the oil tank is provided with a raised portion protruding upward, the air pump is installed on the raised portion, and the air intake pipe of the air pump extends into the raised portion; by providing the raised portion, the air intake pipe opening of the air pump is located at the highest position of the internal cavity of the oil tank, thereby preventing the air pump from discharging the oil in the oil tank.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: when aerial refueling is required, the refueling mechanism of the receiving aircraft extends so that the refueling nozzle is located at the upper part of the nose of the receiving aircraft, reducing the lever effect of the refueling mechanism and making it easier for the receiving aircraft to maintain balance. The refueling aircraft flies to the upper front part of the receiving aircraft, and the refueling mechanism of the refueling aircraft extends so that the refueling nozzle is located at the lower rear part of the refueling aircraft. The refueling aircraft and the receiving aircraft remain relatively stable. The refueling aircraft and the receiving aircraft can fly synchronously or the refueling aircraft and the receiving aircraft hover. The speed, height and angle of the receiving aircraft are adjusted so that the positioning ring and the annular electromagnet are close to each other. The annular electromagnet is energized to generate magnetism, so that the annular electromagnet and the positioning ring can actively absorb and dock when they are close to a certain distance, so that the positioning protrusion of the annular electromagnet is inserted into the positioning ring. At this time, the refueling nozzle and the receiving aircraft are The fuel nozzle is concentrically aligned and the electric push rod contracts, so that the positioning ring pulls the fuel nozzle toward the fuel receiving nozzle through the annular electromagnet, so that the fuel receiving nozzle and the fuel nozzle are docked, and refueling begins. The fuel in the oil tank is input into the fuel tank through the fueling mechanism and the fuel receiving mechanism. After refueling is completed, the electric push rod extends and pushes the positioning ring outward, so that the fuel nozzle and the fuel receiving nozzle are separated, and the annular electromagnet is powered off, so that the annular electromagnet and the positioning ring are separated. The fueling mechanism and the fuel receiving mechanism are folded to the lower middle part of the belly of the fuel tanker and the fuel receiving aircraft respectively. Compared with the prior art, this structural method will not affect the flight and work of the fuel tanker and the fuel receiving aircraft, and the overall structure is more compact and has no protrusions, and has better balance. It reduces the influence of the rotor airflow on the fuel pipe to a greater extent, and assists the docking of the fuel pipe and the fuel receiving pipe by magnetic suction, thereby reducing the difficulty of refueling. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 is a side view structural schematic diagram of the aerial refueling state of the present invention; Figure 3 It is a schematic diagram of the axonometric structure of the present invention in an aerial refueling state when viewed from above; Figure 4 It is a structural schematic diagram of the receiving machine's oil receiving mechanism and other structures in a folded state; Figure 5 It is a side view structural diagram of the receiving machine's oil receiving mechanism and other structures in a folded state; Figure 6 yes Figure 5 A schematic diagram of the local enlarged structure at point A in the middle; Figure 7 yes Figure 3A schematic diagram of the local enlarged structure at B in the middle; Figure 8 It is a schematic diagram of the structure of the oil tank and the oil receiving mechanism; Fig. 9 It is a schematic diagram of the structure of the oil tank, the liquid level sensor, the one-way valve, the air pump and the raised part; Fig.10 It is a structural schematic diagram of the structure of the fuel dispenser and the fueling mechanism; Markings in the attached figure: 1. Fuel dispenser; 2. Oil tank; 3. Fuel receiving machine; 4. Fuel tank; 5. Fueling nozzle; 6. Ring-shaped electromagnet; 7. Fuel receiving nozzle; 8. Electric push rod; 9. Positioning ring; 10. Flip motor 1; 11. Fueling hard pipe; 12. Elastic oil pipe; 13. Spring; 14. Tail assembly; 16. Flip motor 2; 17. Active arm; 18. Driven arm; 19. Pull rod; 20. Fuel receiving pipe; 21. Liquid level sensor; 22. One-way valve; 23. Air pump; 24. Raised part. Implementation

[0019] In order to facilitate understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. Example

[0020] like Figures 1 to 7 As shown, an extended-range UAV aerial refueling system includes a refueling machine 1, an oil bunker 2, a refueling machine 3 and a fuel tank 4. The refueling machine 1 is provided with an oil bunker 2 for carrying oil, and the refueling machine 3 is provided with a fuel tank 4 for supplying oil to the engine. The refueling machine 1 and the refueling machine 3 are both multi-rotor UAVs; characterized in that they also include a refueling nozzle 5, an annular electromagnet 6, a refueling nozzle 7, an electric push rod 8 and a positioning ring 9. The refueling machine 1 is provided with a refueling mechanism folded in the middle and lower part of the belly of the machine and capable of extending toward the rear of the tail of the machine. The input end of the refueling mechanism is connected to the oil bunker 2, and the output end of the refueling mechanism is provided with a refueling nozzle 5. After the refueling mechanism is extended, the refueling nozzle 5 faces downward. An annular electromagnet 6 is mounted on the outer wall of the fueling nozzle 5, and an annular positioning boss is arranged on the end face of the annular electromagnet 6 facing the fueling nozzle 5. The fuel receiving machine 3 is provided with a fuel receiving mechanism which is folded in the middle and lower part of the belly and can be extended to the upper part of the head. The output end of the fuel receiving mechanism is connected with the fuel tank 4, and a fuel receiving nozzle 7 is arranged at the input end of the fuel receiving mechanism. An electric push rod 8 is installed on the outer wall of the fuel receiving nozzle 7, and an annular positioning ring 9 is arranged on the output end of the electric push rod 8. The concentric rings of the positioning ring 9 are arranged outside the fuel receiving nozzle 7, and the positioning ring 9 matches with the positioning boss of the annular electromagnet 6. The annular electromagnet 6 is energized to adsorb the positioning ring 9, and the electric push rod 8 contracts to make the fueling nozzle 5 and the fuel receiving nozzle 7 dock.

[0021] When aerial refueling is required, the refueling mechanism of the receiving aircraft 3 is extended so that the refueling nozzle 7 is located at the upper part of the nose of the receiving aircraft 3, reducing the leverage of the refueling mechanism and making it easier for the receiving aircraft 3 to maintain balance. The tanker 1 flies to the upper front part of the receiving aircraft 3, and the refueling mechanism of the tanker 1 is extended so that the refueling nozzle 5 is located at the lower rear part of the tanker 1. The tanker 1 and the receiving aircraft 3 remain relatively stable. The tanker 1 and the receiving aircraft 3 can fly synchronously or the tanker 1 and the receiving aircraft 3 can hover. The speed, height and angle of the receiving aircraft 3 are adjusted so that the positioning ring 9 and the annular electromagnet 6 are close to each other. The annular electromagnet 6 is energized to generate magnetism, so that the annular electromagnet 6 and the positioning ring 9 can actively absorb and dock when they are close to a certain distance, so that the positioning protrusion of the annular electromagnet 6 is inserted into the positioning ring 9. At this time, the refueling nozzle 5 and the receiving nozzle 7 are concentrically aligned. , the electric push rod 8 contracts, so that the positioning ring 9 pulls the fuel nozzle 5 toward the fuel receiving nozzle 7 through the annular electromagnet 6, so that the fuel receiving nozzle 7 and the fuel nozzle 5 are docked, and refueling begins. The fuel in the oil tank 2 is input into the fuel tank 4 through the fueling mechanism and the fuel receiving mechanism. After refueling is completed, the electric push rod 8 extends to push the positioning ring 9 outward, so that the fuel nozzle 5 and the fuel receiving nozzle 7 are separated, and the annular electromagnet 6 is powered off so that the annular electromagnet 6 and the positioning ring 9 are separated. The fueling mechanism and the fuel receiving mechanism are folded to the lower middle part of the belly of the fuel tanker 1 and the fuel receiving machine 3 respectively. Compared with the prior art, this structural method will not affect the flight and work of the fuel tanker 1 and the fuel receiving machine 3, and the overall structure is more compact and has no protrusions, and the balance is better. The influence of the rotor airflow on the fueling pipe is reduced to a greater extent, and the fueling pipe and the fuel receiving pipe are assisted to dock by magnetic attraction, which reduces the difficulty of refueling.

[0022] As shown in the figure of the flip motor 10, the refueling mechanism includes a flip motor 10, a refueling hard pipe 11 and an elastic oil pipe 12. The flip motor 10 is installed at the lower part of the tail of the refueling machine 1. The output shaft of the flip motor 10 is connected to the inner end of the refueling hard pipe 11 through a clamp. The inner end of the refueling hard pipe 11 is connected to the oil tank 2 through a hose. The oil tank 2 is provided with an oil pump for supplying oil to the refueling hard pipe 11. The flip motor 10 drives the refueling hard pipe 11 to be stored in the lower middle part of the belly of the refueling machine 1 or to extend out of the machine of the refueling machine 1. The rear part of the tail extends out of the coverage range of the rotor, and an elastic oil pipe 12 is arranged at the outer end of the refueling rigid pipe 11. The refueling nozzle 5 and the annular electromagnet 6 are installed on the output end of the elastic oil pipe 12. When the refueling rigid pipe 11 extends out of the rear part of the tail of the refueling machine 1, the elastic oil pipe 12 faces downward; it also includes a spring 13, the spring 13 is sleeved on the elastic oil pipe 12, and the spring 13 strengthens the elasticity of the elastic oil pipe 12; it also includes a tail group 14, the outer end of the refueling rigid pipe 11 is provided with a tail group 14, and the tail group 14 is provided with a plurality of wing surfaces.

[0023] In the non-refueling state, the flip motor 10 drives the refueling rigid pipe 11 and the elastic oil pipe 12 to be horizontally folded and stored under the middle part of the belly of the refueling machine 1, so that the overall structure of the refueling machine 1 is compact without protrusions, and it is easier to maintain flight stability. In the refueling state, the flip motor 10 drives the refueling rigid pipe 11 and the elastic oil pipe 12 to rotate, so that the refueling rigid pipe 11 and the elastic oil pipe 12 are flipped to the rear of the tail of the refueling machine 1. Since the refueling rigid pipe 11 is located between the two rotors at the center line of the refueling machine 1, it can minimize the impact of airflow. The elastic oil pipe 12 is downward, which is convenient for the refueling machine 1. Maintaining a certain height difference with the receiving aircraft 3 can reduce the possibility of collision during refueling. During refueling, the oil pump in the oil tank 2 delivers oil to the refueling mechanism of the receiving aircraft 3 through the hose, the refueling rigid pipe 11 and the elastic oil pipe 12. The spring 13 is mounted on the elastic oil pipe 12, so that the elastic oil pipe 12 reduces the amplitude of shaking when subjected to wind and airflow, thereby reducing the difficulty of docking during refueling. By arranging a tail group 14 on the outer end of the refueling rigid pipe 11, when the refueling machine 1 and the receiving aircraft 3 are refueling in a flying state, the horizontal airflow acts on the tail group 14, thereby stabilizing the refueling rigid pipe 11.

[0024] like Figure 8 As shown, the oil receiving mechanism includes a second flip motor 16, an active arm 17, a driven arm 18, a tie rod 19 and an oil receiving pipe 20. The second flip motor 16 is installed at the middle and upper part of the nose of the oil receiving machine 3. The output end of the second flip motor 16 is fixedly connected to one end of the active arm 17, and the other end of the active arm 17 is rotatably connected to one end of the driven arm 18. One end of the driven arm 18 is also rotatably connected to one end of the tie rod 19, and the other end of the tie rod 19 is rotatably connected to the middle part of the nose of the oil receiving machine 3. The oil receiving pipe 20 is installed on the driven arm 18. The input end of the oil receiving pipe 20 is connected to the oil tank 4 through a hose, and the oil receiving nozzle 7 is installed on the output end of the oil receiving pipe 20. When the flip motor 16 drives the active arm 17 to rotate toward the lower part of the nose of the oil receiving machine 3, the supporting effect of the pull rod 19 causes the driven arm 18 and the oil receiving pipe 20 to be horizontally folded and stored under the middle part of the belly of the oil receiving machine 3. When the flip motor 16 drives the active arm 17 to rotate toward the upper part of the nose of the oil receiving machine 3, the pulling effect of the pull rod 19 causes the driven arm 18 and the oil receiving pipe 20 to extend vertically to the top of the nose of the oil receiving machine 3.

[0025] The active arm 17, the driven arm 18 and the tie rod 19 form a connecting rod structure, and the positions of the output shaft A of the flip motor 16, the connection point B between the tie rod 19 and the oil receiving machine 3, the connection point C between the active arm 17 and the driven arm 18, and the connection point D between the driven arm 18 and the tie rod 19 are optimized so that A is located above and behind B, and the circular motion trajectory of D is located inside the circular motion trajectory of C. When the flip motor 16 drives the active arm 17 to move from vertical upward to vertical downward, the distance between C and B gradually decreases, and the distance between D and A gradually increases, so as to realize the conversion of the pull rod 19 from pulling to supporting the driven arm 18. Only one power source is needed for the two actions, thereby simplifying the structure and improving practicality.

[0026] like Figure 8 and Fig. 9 As shown, it also includes a liquid level sensor 21, which is installed on the fuel tank 4. The liquid level sensor 21 detects the oil level in the fuel tank 4. The liquid level sensor 21 is electrically connected to the control system of the fuel receiving machine 3; it also includes a one-way valve 22. An oil inlet pipe is arranged on the oil inlet of the fuel tank 4. The oil inlet pipe is connected to the fuel receiving pipe 20 through a hose. The one-way valve 22 is arranged on the oil inlet pipe. The one-way valve 22 blocks the oil in the fuel tank 4 from flowing back; it also includes an air pump 23, which is installed on the fuel tank 4. When refueling, the air pump 23 is started to pump the upper cavity of the fuel tank 4 into a low-pressure state; it also includes a protrusion 24, which is arranged on the fuel tank 4 and protrudes upward. The air pump 23 is installed on the protrusion 24, and the air inlet pipe of the air pump 23 extends into the protrusion 24; When the liquid level sensor 21 detects that the oil in the fuel tank 4 has reached a low level, the control system sends a signal that refueling is required and starts to return for refueling or perform aerial refueling. When the liquid level sensor 21 detects that the oil in the fuel tank 4 has reached a high level, the control system sends a signal to stop refueling, thereby improving the degree of automation. By providing a one-way valve 22, a siphon phenomenon is avoided when the follower arm 18 and the oil receiving pipe 20 are folded and stored under the belly of the receiving aircraft 3, which causes oil reflux and leakage. Through the suction of the air pump 23, the cavity at the upper part of the fuel tank 4 forms a low-pressure state, so that the oil is quickly input into the fuel tank 4, thereby improving the refueling speed. By providing a protrusion 24, the air inlet of the air pump 23 is located at the highest position of the internal cavity of the fuel tank 4, thereby preventing the air pump 23 from discharging the oil in the fuel tank 4.

[0027] like Figures 1 to 10As shown in the flip motor 10, an extended-range UAV aerial refueling system of the present invention, when working, first when the liquid level sensor 21 detects that the oil in the fuel tank 4 reaches a low level, the control system sends a signal that refueling is required, and aerial refueling begins. The tanker 1 flies to the receiving aircraft 3, and then the flip motor 2 16 drives the active arm 17 and the driven arm 18 to flip toward the upper part of the nose of the receiving aircraft 3, and at the same time, the pulling action of the pull rod 19 causes the driven arm 18 to flip to a vertical state, so that the receiving nozzle 7 is located at the upper part of the nose of the receiving aircraft 3, and refueling is completed. The tanker 1 flies to the front upper part of the receiving aircraft 3, and the flip motor 10 drives the refueling rigid pipe 11 and the elastic oil pipe 12 to rotate, so that the refueling rigid pipe 11 and the elastic oil pipe 12 are flipped to the rear of the tail of the tanker 1, so that the refueling nozzle 5 is at the rear lower part of the tanker 1, and then the tanker 1 and the receiving aircraft 3 remain relatively stable, the tanker 1 and the receiving aircraft 3 can fly synchronously or the tanker 1 and the receiving aircraft 3 can hover, and the speed, height and angle of the receiving aircraft 3 are adjusted, so that the positioning ring 9 and the annular electromagnet 6 are close, and the annular electromagnet 6 is energized to generate a magnetic field. The ring-shaped electromagnet 6 and the positioning ring 9 can actively adsorb and dock when they are close to a certain distance, so that the positioning protrusion of the ring-shaped electromagnet 6 is inserted into the positioning ring 9. At this time, the fueling nozzle 5 and the receiving nozzle 7 are concentrically aligned, and the electric push rod 8 shrinks, so that the positioning ring 9 pulls the fueling nozzle 5 to the receiving nozzle 7 through the ring-shaped electromagnet 6, so that the receiving nozzle 7 and the fueling nozzle 5 dock, and the air pump 23 starts to pump air, so that the cavity at the top of the fuel tank 4 forms a low-pressure state, and refueling begins. The fuel in the oil tank 2 passes through the refueling hard pipe 11, the elastic oil pipe 12, and the receiving nozzle 7. The pipe 20 is input into the fuel tank 4. When the liquid level sensor 21 detects that the oil in the fuel tank 4 has reached a high level, the control system sends a signal to stop refueling. Finally, the refueling is completed, the electric push rod 8 extends to push the positioning ring 9 outward, so that the refueling nozzle 5 and the refueling nozzle 7 are separated, and the annular electromagnet 6 is powered off so that the annular electromagnet 6 and the positioning ring 9 are separated. The refueling hard pipe 11 and the driven arm 18 are folded to the lower middle part of the belly of the refueling machine 1 and the refueling machine 3 respectively. The one-way valve 22 blocks the reflux of the oil, the refueling machine 1 returns, and the refueling machine 3 continues to work.

[0028] The main functions achieved by the present invention are: 1. The refueling method with the refueling machine and the receiving machine staggered in height is adopted, which is highly safe; 2. The refueling and receiving mechanism can be folded and unfolded, the overall structure is more compact without protrusion and has better balance; 3. The oil receiving pipe extends upward, which is not affected by the rotor airflow and is convenient for docking; 4. The refueling pipe and the receiving pipe are connected by magnetic suction, which reduces the difficulty of refueling; 5. The refueling pipe adopts a combination of hard pipe and elastic hose, so that the connection has a certain degree of flexibility.

[0029] The installation method, connection method or setting method of the extended-range UAV aerial refueling system of the present invention are all common mechanical methods, and can be implemented as long as they can achieve their beneficial effects; the refueling machine 1, oil tank 2, refueling machine 3, fuel tank 4, refueling nozzle 5, annular electromagnet 6, refueling nozzle 7, electric push rod 8, positioning ring 9, flip motor 10, spring 13, flip motor 2 16, refueling pipe 20, liquid level sensor 21, one-way valve 22, and vacuum pump 23 of the extended-range UAV aerial refueling system of the present invention are purchased on the market, and technical personnel in the industry only need to install and operate them according to the accompanying instruction manual, without the need for technical personnel in this field to make creative labor.

[0030] All technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0031] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An extended-range UAV aerial refueling system, comprising a refueling machine (1), a fuel tank (2), a refueling machine (3) and a fuel tank (4), wherein the refueling machine (1) is provided with a fuel tank (2) for carrying fuel, and the refueling machine (3) is provided with a fuel tank (4) for supplying fuel to an engine, and the refueling machine (1) and the refueling machine (3) are both multi-rotor UAVs; characterized in that: The invention also comprises a refueling nozzle (5), an annular electromagnet (6), a refueling nozzle (7), an electric push rod (8) and a positioning ring (9). The refueling machine (1) is provided with a refueling mechanism which is folded in the middle and lower part of the belly of the machine and can be extended toward the rear of the tail of the machine. The input end of the refueling mechanism is connected to the oil tank (2). The output end of the refueling mechanism is provided with a refueling nozzle (5). After the refueling mechanism is extended, the refueling nozzle (5) faces downward. The outer wall of the refueling nozzle (5) is provided with an annular electromagnet (6). The end surface of the annular electromagnet (6) facing the refueling nozzle (5) is provided with an annular positioning boss. The refueling machine (3) is provided with a refueling mechanism which is folded in the machine. An oil receiving mechanism is disposed in the lower middle part of the abdomen and can extend toward the upper part of the machine head. The output end of the oil receiving mechanism is connected to the oil tank (4). The input end of the oil receiving mechanism is provided with an oil receiving nozzle (7). An electric push rod (8) is installed on the outer wall of the oil receiving nozzle (7). An annular positioning ring (9) is provided on the output end of the electric push rod (8). The positioning ring (9) is concentrically arranged outside the oil receiving nozzle (7). The positioning ring (9) matches the positioning boss of the annular electromagnet (6). When the annular electromagnet (6) is energized to adsorb the positioning ring (9), the electric push rod (8) contracts to make the oiling nozzle (5) and the oil receiving nozzle (7) butt joint.

2. The extended-range UAV aerial refueling system according to claim 1, characterized in that: The refueling mechanism comprises a tilting motor (10), a refueling tube (11) and an elastic oil tube (12). The tilting motor (10) is mounted at the lower part of the tail of the refueling machine (1). The output shaft of the tilting motor (10) is connected to the inner end of the refueling tube (11) through a clamping member. The inner end of the refueling tube (11) is connected to an oil tank (2) through a hose. The oil tank (2) is provided with an oil pump for supplying oil to the refueling tube (11). The tilting motor (10) drives the refueling tube (11) to be stored in the middle and lower part of the belly of the refueling machine (1) or to extend out of the rear part of the tail of the refueling machine (1) and extend out of the coverage range of the rotor. The elastic oil tube (12) is arranged at the outer end of the refueling tube (11). The refueling nozzle (5) and the annular electromagnet (6) are mounted on the output end of the elastic oil tube (12). When the refueling tube (11) extends out of the rear part of the tail of the refueling machine (1), the elastic oil tube (12) faces downward.

3. The extended-range UAV aerial refueling system according to claim 2, characterized in that: It also includes a spring (13), which is sleeved on the elastic oil pipe (12) and strengthens the elasticity of the elastic oil pipe (12).

4. The extended-range UAV aerial refueling system according to claim 2, characterized in that: It also comprises a tail wing group (14), wherein the tail wing group (14) is arranged at the outer end of the refueling hard pipe (11), and the tail wing group (14) is provided with a plurality of wing surfaces.

5. The extended-range UAV aerial refueling system according to claim 1, characterized in that: The oil receiving mechanism comprises a second tilting motor (16), a driving arm (17), a driven arm (18), a pull rod (19) and an oil receiving pipe (20). The second tilting motor (16) is installed at the middle upper part of the head of the oil receiving machine (3). The output end of the second tilting motor (16) is fixedly connected to one end of the driving arm (17). The other end of the driving arm (17) is rotatably connected to one end of the driven arm (18). One end of the driven arm (18) is also rotatably connected to one end of the pull rod (19). The other end of the pull rod (19) is rotatably connected to the middle part of the head of the oil receiving machine (3). The oil receiving pipe (20) is installed on the driven arm (18). The input end of the pipe (20) is connected to the oil tank (4) through a hose, and the oil receiving nozzle (7) is installed on the output end of the oil receiving pipe (20). When the second flip motor (16) drives the active arm (17) to rotate toward the lower part of the head of the oil receiving machine (3), the supporting effect of the pull rod (19) causes the driven arm (18) and the oil receiving pipe (20) to be horizontally folded and stored below the middle part of the belly of the oil receiving machine (3). When the second flip motor (16) drives the active arm (17) to rotate toward the upper part of the head of the oil receiving machine (3), the pulling effect of the pull rod (19) causes the driven arm (18) and the oil receiving pipe (20) to extend vertically to the upper part of the head of the oil receiving machine (3).

6. The extended-range UAV aerial refueling system according to claim 1, characterized in that: It also includes a liquid level sensor (21) mounted on the oil tank (4), the liquid level sensor (21) detecting the oil level in the oil tank (4), and the liquid level sensor (21) being electrically connected to a control system of the oil receiving machine (3).

7. The extended-range UAV aerial refueling system according to claim 1, characterized in that: It also includes a one-way valve (22). An oil inlet pipe is provided on the oil inlet of the oil tank (4). The oil inlet pipe is connected to the oil receiving pipe (20) via a hose. The one-way valve (22) is provided on the oil inlet pipe. The one-way valve (22) blocks the oil in the oil tank (4) from flowing back.

8. The extended-range UAV aerial refueling system according to claim 1, characterized in that: It also includes an air pump (23) which is mounted on the oil tank (4). When refueling, the air pump (23) is started to pump the upper cavity of the oil tank (4) into a low-pressure state.

9. The extended-range UAV aerial refueling system according to claim 8, characterized in that: It also includes a raised portion (24), wherein the oil tank (4) is provided with a raised portion (24) that protrudes upward, the air extractor (23) is mounted on the raised portion (24), and the air intake pipe of the air extractor (23) extends into the raised portion (24).

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