Aerial refueling flexible drogue and method of refueling

Abstract

The application belongs to the field of aerial autonomous refueling, and relates to an aerial refueling flexible receiving plug and a receiving method. The flexible receiving plug has a hollow structure inside for placing an oil pipeline; the receiving plug comprises a plug base, a rope-driven deflection unit, a gas-driven telescopic unit, a visual perception unit and a power system unit; the gas-driven telescopic unit and the rope-driven deflection unit are adopted to make the plug have high flexibility and self-adaptive capacity, and the plug is not constrained by high-speed or low-speed flight. A depth camera is used as a visual sensor to realize real-time perception and control of the plug, so that the plug has higher precision and safety. The coupling of the gas-driven joint and the wire-driven joint makes the plug more accurate in motion trajectory control, and since the wire-driven joint uses steel wire as a driving material, compared with other transmission modes, the wire-driven joint has lower maintenance cost and longer service life. In addition, the plug has simple structure, relatively low manufacturing cost and is easier to maintain.

Description

Technical Field

[0001] This invention belongs to the field of autonomous aerial refueling and relates to a flexible refueling probe and refueling method for aerial refueling. Background Technology

[0002] The flexible refueling receiver plug is a crucial component connecting the refueling and receiving aircraft, enabling fuel transfer between them. Common types of flexible refueling receiver plugs include: The omnidirectional flexible receiver plug, composed of multiple movable joints, is simple in design and easy to operate, adapting to various angles and attitudes while receiving fuel. Furthermore, this type of plug is suitable for different types of receiving aircraft and has low maintenance costs. However, it is susceptible to vibration and instability due to gravity and airflow, requiring highly experienced pilots to operate. In contrast, the fly-by-wire flexible receiver plug transmits data and signals via cables, allowing for more precise control of fuel transfer speed and flow. It also monitors the plug's status and transmits data to the pilot or system in real time, ensuring refueling safety. However, in extreme situations, such as lightning strikes or electromagnetic interference, signal transmission errors may occur. Unlike the above two types, the inertial flexible receiver plug, composed of two interconnected metal tubes, can automatically adjust the contact point position to adapt to different aircraft attitude changes. It is also faster than the omnidirectional flexible receiver plug, better suppressing vibration and instability, making the refueling process faster, smoother, and safer. However, the inertial flexible oil probe design is complex and costly, making it unsuitable for low-speed applications.

[0003] Besides the three types mentioned above, there are also some new types of flexible refueling probes, such as elastic flexible refueling probes and combined hot and cold flexible refueling probes. Although these significantly improve the stability and reliability of aerial refueling mechanisms, their complex designs make them prone to failure and result in high maintenance costs. Aerial refueling probes need to operate in areas of strong interference ahead, subject to interference from complex airflow such as the tanker's wake vortex and nose wave, making them susceptible to multiple effects from aircraft vibration and airflow disturbances. Therefore, flexible deformable refueling probes for aerial refueling need to possess high-precision pitch, deflection, extension, dynamic sealing, and impact pressure suppression functions, while also ensuring a simple overall structure and ease of subsequent maintenance.

[0004] In fact, transferring these functional requirements to the field of robotics can approximate a complete flexible exolimb robot system. This invention applies the multi-segment continuous structure design concept of continuum robots to the field of aviation refueling technology, possessing the characteristics of relative convenience and strong robustness, and can adapt to relatively complex working environments. Currently, such systems mainly include two types of drive methods: one is high-precision controlled cable drive, and the other is lightweight, high-extensibility fluid (gas / liquid) drive. To meet the high precision, rapid response, and shock resistance performance requirements of the new plug system, a single drive method cannot meet the requirements. Therefore, a novel design scheme is needed that combines an efficient and reliable integrated mechanical structure with accurate visual positioning feedback and ease of subsequent maintenance. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of flexible refueling probes for aerial refueling, despite their high level of maturity and practicality. Due to their complex structure, including multiple joints and transmission mechanisms, these probes require lubrication and maintenance during routine operations to ensure system stability. This results in relatively high maintenance costs and unsuitability for low-speed applications. Furthermore, flexible refueling probes are highly susceptible to external environmental influences, leading to instability and fluctuations during operation. This invention addresses this by cleverly integrating the refueling pipe into a continuous robot structure. Through the design of telescopic and offset joints, the refueling pipe gains a degree of mobility, ensuring more stable insertion into the parachute.

[0006] This invention aims to address the challenges of complex multi-joint structures and the significant role of pilot experience in the refueling process, proposing a novel flexible refueling connector and method. It improves the connector system's resistance to disturbances and incorporates visual sensing at the intermediate joint for information feedback, reducing the limitations imposed by pilot experience. Simultaneously, it eliminates the impact of high-speed or low-speed flight on the refueling process. Through visual feedback signals, the main controller can acquire real-time parachute target data, design a tracking controller, and autonomously achieve refueling docking, greatly improving refueling efficiency.

[0007] The technical solution of this invention: A flexible deformable refueling probe for aerial refueling, wherein the flexible deformable refueling probe has a hollow internal structure for housing the refueling pipeline; it includes a probe base, a cable-driven deflection unit, a pneumatic telescopic unit, a vision sensing unit, and a power system unit; one end of the probe base is connected to the power system unit, and the other end is connected to the pneumatic telescopic unit, the other end of the pneumatic telescopic unit is connected to the cable-driven deflection unit, the vision sensing unit is installed on the coupling joint a1 of the cable-driven deflection unit, the power system is connected to the base by bolts, the base cooperates with the pneumatic telescopic unit, the pneumatic telescopic unit and the cable-driven deflection unit are coupled to each other, and the components of each unit are connected by a locking mechanism, and the entire probe is wrapped by a retractable flexible outer sleeve.

[0008] The pneumatically driven telescopic unit has a cylindrical overall shape and consists of three artificial pneumatic muscles. These three muscles are evenly distributed along the axial direction, with a 2cm distance between the outer walls of every two muscles. The gaps are used to house six ropes for the rope-driven biasing unit. These six ropes are then connected to the power system. Each pneumatic muscle has an air tube at its tail, which connects to the pneumatic pressure regulating part of the power system. A 0.4m long rope is reserved on the outside of the coupling joint c3 of the rope-driven deflection unit to enable subsequent bending functions.

[0009] The cable-driven deflection unit is conical and includes coupling joint a1, coupling joint b2, coupling joint c3, and six cables. Coupling joint a1 and coupling joint b2 constitute the first cable-driven unit, and coupling joint b2 and coupling joint c3 constitute the second cable-driven unit. One end of three cables is fixed to coupling joint c3 by a buckle, and the other end passes through coupling joint b2, coupling joint a1, and the pneumatic telescopic unit in sequence to connect with the power system. One end of another three cables is fixed to coupling joint b2 by a buckle, and the other end passes through coupling joint a1 and the pneumatic telescopic unit in sequence to be fixedly connected with the power system.

[0010] The aforementioned visual perception unit is used to collect target information of the receiving aircraft. It is connected to the Jetson nano controller at the rear of the base via a signal line to realize the acquisition of visual signals.

[0011] The visual perception unit consists of a miniature depth camera module, with the camera embedded at the outer edge of the coupling joint a1, allowing for unobstructed observation of the surrounding environment.

[0012] The power system includes an electric drive system composed of servo motors and an air pressure regulation system composed of air pumps. The main controller for both the power system and the vision perception unit is the same Jetson nano.

[0013] The through holes a4, b5, and c6 in coupling joints a1, b2, and c3 are used to house the oil pipeline. Coupling joints a1 and b2 each have six small through holes with a diameter of 1.5 cm, 1 cm from the outer wall. Coupling joint c3 has three small through holes with a diameter of 1.5 cm. The six small through holes 11, 12, 13, 14, 15, and 16 in coupling joint a1 are used for the cable of the wire-driven bias unit to pass through; coupling joint a1 is considered a transmission disk. Of the six small through holes in coupling joint b2, three through holes 21, 23, and 25 are used for fixing the cable lock of the first section of the cable drive unit, and 22, 24, and 26 are used for the cable of the first section of the cable drive unit to pass through and are fixed to the outside of the three small through holes 31, 32, and 33 in coupling joint c3.

[0014] The coupling joint a1 disk has an outer ring bracket for embedding a miniature camera, and the signal line can be routed through the internal gap of the pneumatic telescopic unit.

[0015] The aforementioned aerial refueling flexible deformable refueling probe method involves connecting a rope pre-installed in the rope drive unit to the electric drive system in the power system. Controlling the rotation of the servo motor drives the rope to deflect, achieving different degrees of freedom of bending, thus moving the refueling pipe. The air pump system in the power system controls the output air pressure, allowing the probe to extend and retract to varying degrees. Using the receiver aircraft's position information acquired by the visual perception unit, the pressure regulating valve of the air pump system is increased, causing the air-driven extension unit to extend. Next, the operation of different servo motors in the electric drive system is controlled to complete the traction of each rope, enabling the refueling pipe to move in all directions (up, down, left, right), ultimately allowing the refueling pipe to be accurately inserted into the parachute cover.

[0016] Both the electric drive system and the air pressure regulation system are controlled by the main controller Jeston Nano.

[0017] The significant effects of this invention are:

[0018] This invention employs a pneumatically driven telescopic unit and a rope-driven deflection unit, which gives the plug high flexibility and adaptability, freeing it from the constraints of high-speed or low-speed flight. Furthermore, using a depth camera as a visual sensor enables real-time perception and control of the plug, resulting in higher precision and safety. Compared to traditional flexible deformable oil receiving plugs, the new plug is more intelligent and convenient.

[0019] Meanwhile, this solution employs a coupling of pneumatic and wire-driven joints, resulting in more precise control of the plug's motion trajectory. Furthermore, because the wire-driven joint uses steel wire as the driving material, it has lower maintenance costs and a longer lifespan compared to other transmission methods. In addition, the plug has a simple structure, relatively low manufacturing costs, and is easier to maintain. In summary, this invention has high practicality and feasibility, and can bring a more intelligent and efficient operating method to aerial refueling systems. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the flexible deformable plug structure for aerial refueling of the present invention;

[0021] Figure 2 This is a schematic diagram of the coupling joints in the flexible deformable plug for aerial refueling of the present invention;

[0022] Figure 3 This is a schematic diagram of the three-dimensional overall structure of the flexible deformable plug for aerial refueling of the present invention;

[0023] Wherein: 1-coupled joint a, 2-coupled joint b, 3-coupled joint c, 4-through hole a, 5-through hole b, 6-through hole c, 11-first through hole of coupled joint a1, 12-second through hole of coupled joint a1, 13-third through hole of coupled joint a1, 14-fourth through hole of coupled joint a1, 15-fifth through hole of coupled joint a1, 16-sixth through hole of coupled joint a1, 21-first through hole of coupled joint b2, 22-second through hole of coupled joint b2, 23-third through hole of coupled joint b2, 24-fourth through hole of coupled joint b2, 25-fifth through hole of coupled joint b2, 26-sixth through hole of coupled joint b2, 31-first through hole of coupled joint c3, 32-second through hole of coupled joint c3, 33-third through hole of coupled joint c3. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings:

[0025] like Figure 1-3 As shown, an aerial refueling flexible deformable refueling probe is disclosed. The probe has a hollow internal structure for housing the refueling pipeline. It includes a probe base, a cable-driven deflection unit, a pneumatic telescopic unit, a vision sensing unit, and a power system unit. One end of the probe base is connected to the power system unit, and the other end is connected to the pneumatic telescopic unit. The other end of the pneumatic telescopic unit is connected to the cable-driven deflection unit. The vision sensing unit is mounted on the coupling joint a1 of the cable-driven deflection unit. The power system is connected to the base by bolts. The base cooperates with the pneumatic telescopic unit, which is coupled to the cable-driven deflection unit. The components are connected by a locking mechanism. The entire probe is covered by a retractable flexible outer sleeve.

[0026] The pneumatically driven telescopic unit has a cylindrical overall shape and consists of three artificial pneumatic muscles. These three muscles are evenly distributed along the axial direction, with a 2cm distance between the outer walls of every two muscles. The gaps are used to house six ropes for the rope-driven biasing unit. These six ropes are then connected to the power system. Each pneumatic muscle has an air tube at its tail, which connects to the pneumatic pressure regulating part of the power system. A 0.4m long rope is reserved on the outside of the coupling joint c3 of the rope-driven deflection unit to enable subsequent bending functions.

[0027] The cable-driven deflection unit is conical and includes coupling joint a1, coupling joint b2, coupling joint c3, and six cables. Coupling joint a1 and coupling joint b2 constitute the first cable-driven unit, and coupling joint b2 and coupling joint c3 constitute the second cable-driven unit. One end of three cables is fixed to coupling joint c3 by a buckle, and the other end passes through coupling joint b2, coupling joint a1, and the pneumatic telescopic unit in sequence to connect with the power system. One end of another three cables is fixed to coupling joint b2 by a buckle, and the other end passes through coupling joint a1 and the pneumatic telescopic unit in sequence to be fixedly connected with the power system.

[0028] The aforementioned visual perception unit is used to collect target information of the receiving aircraft. It is connected to the Jetson nano controller at the rear of the base via a signal line to realize the acquisition of visual signals.

[0029] The visual perception unit consists of a miniature depth camera module, with the camera embedded at the outer edge of the coupling joint a1, allowing for unobstructed observation of the surrounding environment.

[0030] The power system includes an electric drive system composed of servo motors and an air pressure regulation system composed of air pumps. The main controller for both the power system and the vision perception unit is the same Jetson nano.

[0031] The through holes a4, b5, and c6 in coupling joints a1, b2, and c3 are used to house the oil pipeline. Coupling joints a1 and b2 each have six small through holes with a diameter of 1.5 cm, 1 cm from the outer wall. Coupling joint c3 has three small through holes with a diameter of 1.5 cm. The six small through holes 11, 12, 13, 14, 15, and 16 in coupling joint a1 are used for the cable of the wire-driven bias unit to pass through; coupling joint a1 is considered a transmission disk. Of the six small through holes in coupling joint b2, three through holes 21, 23, and 25 are used for fixing the cable lock of the first section of the cable drive unit, and 22, 24, and 26 are used for the cable of the first section of the cable drive unit to pass through and are fixed to the outside of the three small through holes 31, 32, and 33 in coupling joint c3.

[0032] The coupling joint a1 disk has an outer ring bracket for embedding a miniature camera, and the signal line can be routed through the internal gap of the pneumatic telescopic unit.

[0033] The aforementioned aerial refueling flexible deformable refueling probe method involves connecting a rope pre-installed in the rope drive unit to the electric drive system in the power system. Controlling the rotation of the servo motor drives the rope to deflect, achieving different degrees of freedom of bending, thus moving the refueling pipe. The air pump system in the power system controls the output air pressure, allowing the probe to extend and retract to varying degrees. Using the receiver aircraft's position information acquired by the visual perception unit, the pressure regulating valve of the air pump system is increased, causing the air-driven extension unit to extend. Next, the operation of different servo motors in the electric drive system is controlled to complete the traction of each rope, enabling the refueling pipe to move in all directions (up, down, left, right), ultimately allowing the refueling pipe to be accurately inserted into the parachute cover.

[0034] Both the electric drive system and the air pressure regulation system are controlled by the main controller Jeston Nano.

Claims

1. A flexible deformable refueling probe for aerial refueling, characterized in that, The flexible deformable oil receiving plug has a hollow internal structure for placing oil pipelines; it includes a plug base, a rope-driven deflection unit, a pneumatic telescopic unit, a visual perception unit, and a power system unit; one end of the plug base is connected to the power system unit, and the other end is connected to the pneumatic telescopic unit, the other end of the pneumatic telescopic unit is connected to the rope-driven deflection unit, the visual perception unit is installed on the coupling joint a (1) of the rope-driven deflection unit, the power system is connected to the base by bolts, the base is matched with the pneumatic telescopic unit, the pneumatic telescopic unit and the rope-driven deflection unit are coupled to each other, and the components of each unit are connected by a locking mechanism. The entire plug is wrapped with a retractable flexible outer jacket; the rope-driven deflection unit is conical and includes coupling joint a (1), coupling joint b (2), coupling joint c (3) and 6 ropes; Coupled joint a (1) and coupled joint b (2) constitute the first rope drive unit, and coupled joint b (2) and coupled joint c (3) constitute the second rope drive unit; 3 One end of a rope is fixed to the coupling joint c (3) by a buckle, and the other end passes through the coupling joint b (2), the coupling joint a (1) and the pneumatic telescopic unit in sequence to connect with the power system; the other three ropes are fixed to the coupling joint b (2) by a buckle, and the other end passes through the coupling joint a (1) and the pneumatic telescopic unit in sequence to connect with the power system.

2. The flexible deformable refueling probe for aerial refueling according to claim 1, characterized in that, The pneumatically driven telescopic unit has a cylindrical overall appearance and is composed of three artificial pneumatic muscles inside. The three artificial pneumatic muscles are evenly distributed along the axial direction. The distance between the outer walls of every two artificial pneumatic muscles is 2cm. The interval is used to place the six ropes of the rope-driven biasing unit. The six ropes are then connected to the power system. Each pneumatic muscle has an air tube at its tail, which is connected to the pneumatic pressure regulating part in the power system. A 0.4m long rope is reserved on the outside of the coupling joint c(3) of the rope-driven deflection unit to realize the subsequent bending function.

3. The flexible deformable refueling probe for aerial refueling according to claim 1, characterized in that, The aforementioned visual perception unit is used to collect target information of the receiving aircraft. It is connected to the Jetson nano controller at the rear of the base via a signal line to realize the acquisition of visual signals.

4. The flexible deformable refueling probe for aerial refueling according to claim 1, characterized in that, The visual perception unit consists of a miniature depth camera module, with the camera embedded at the outer edge of the coupling joint a(1), allowing for unobstructed observation of the environment ahead.

5. The flexible deformable refueling probe for aerial refueling according to claim 1, characterized in that, The power system includes an electric drive system composed of servo motors and an air pressure regulation system composed of air pumps; the main controller of the power system and the vision perception unit are the same Jetson nano.

6. The flexible deformable refueling probe for aerial refueling according to claim 1, characterized in that, The through holes a (4), b (5) and c (6) in the coupling joints a (1), b (2) and c (3) are used to place the oil pipe; there are 6 small through holes with a diameter of 1.5 cm evenly distributed on the coupling joints a (1) and b (2), 1 cm away from the outer wall; there are 3 small through holes with a diameter of 1.5 cm evenly distributed on the coupling joints c (3).

7. The flexible deformable refueling probe for aerial refueling according to claim 4, characterized in that, The coupling joint a(1) has a circular bracket on the outside of the disk for embedding a miniature camera. The signal line can be routed through the internal gap of the pneumatic telescopic unit.

8. The method for receiving fuel using the flexible deformable refueling probe for aerial refueling according to any one of claims 1-7, characterized in that, The ropes, pre-installed in the rope drive unit, are connected to the electric drive system in the power system. The rotation of the servo motor is controlled to drive the ropes to deflect, achieving different degrees of freedom of bending, thus moving the oil pipeline. The output air pressure of the air pump system in the power system is controlled to allow the plug to extend and retract to different degrees. Based on the position information of the receiving machine collected by the vision perception unit, the pressure regulating valve of the air pump system is increased to extend the air-driven telescopic unit. Then, the operation of different servo motors in the electric drive system is controlled to complete the traction of each rope, so as to move the oil pipeline in all directions (up, down, left, right), ultimately allowing the oil pipeline to be accurately inserted into the umbrella cover.

9. The method for receiving fuel using the flexible deformable refueling probe for aerial refueling according to claim 8, characterized in that, Both the electric drive system and the air pressure regulation system are controlled by the main controller Jeston Nano.

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