An unmanned aerial vehicle suitable for exploration of titan

Abstract

The application discloses an unmanned aerial vehicle suitable for Titan exploration, belongs to the field of aircraft design, and is based on the atmospheric environment of Titan and the development status of domestic deep space exploration related technologies to propose a design scheme of a Titan unmanned aerial vehicle exploration platform, which comprises overall layout design based on the environmental characteristics of Titan and exploration requirements, basic overall parameter design under the constraint of the size of a reentry device and the carrying capacity of a rocket based on the determination of the overall layout, and preliminary structure scheme and overall arrangement design, and the like. In the structure design of the unmanned aerial vehicle, a folding unmanned aerial vehicle is adopted, and the folding and unfolding mode and position are designed. The application comprehensively analyzes the environmental characteristics of Titan, and completes innovative design of an energy system, a communication system and a complete working process of a fixed-wing unmanned aerial vehicle working in a non-typical earth atmospheric environment, so that the unmanned aerial vehicle can provide a reference for the design of a deep space exploration probe for an extraterrestrial planet with an atmosphere.

Description

Technical Field

[0002] This invention relates to the field of aircraft design, specifically to an unmanned aerial vehicle suitable for exploration of Titan. Background Technology

[0004] As research into the origins of the universe, the development and changes of celestial bodies, and the origins and evolution of life deepens, the demand for scientific exploration and research into deep space environments continues to grow. Titan, the only moon in the solar system with an atmosphere, possesses immense scientific value in multiple research fields due to its unique environment. However, Titan's great distance from Earth necessitates that unmanned aerial vehicles (UAVs) be housed within the reentry vehicles of launch vehicles before reaching its atmosphere, severely limiting their size. Conventional energy systems are unsuitable for Titan's extremely cold, oxygen-free, and low-light environment. These factors make the design of a Titan exploration UAV extremely challenging.

[0005] To address the unique exploration environment of atmospheric celestial bodies in deep space, researchers both domestically and internationally have conducted extensive research and conceptualization, proposing various airborne exploration platforms, including rotary-wing UAVs, airships, phase-change balloons, and hot air balloons. However, due to the differences between Titan's atmosphere and Earth's atmosphere—characterized by low gravitational acceleration and high atmospheric density—the empirical formulas for overall spacecraft design derived from repeated experiments in Earth's atmosphere are not applicable to the calculation of corresponding parameters for a Titan UAV. Furthermore, the Titan UAV faces challenges not encountered by Earth-based UAVs, such as prolonged standby within a rocket and difficulties in energy supply. Currently, a complete overall design scheme for a Titan UAV is lacking. Summary of the Invention

[0007] To address the aforementioned issues, this invention proposes an overall design scheme for an unmanned aerial vehicle (UAV) suitable for Titan exploration. The overall parameters of the Titan exploration UAV are determined, and the basic design of subsystems such as the energy system and temperature control system is completed, enabling the designed Titan exploration UAV to complete the entire process of the Titan exploration mission from rocket installation to the end of its lifespan.

[0008] This invention relates to an unmanned aerial vehicle (UAV) for exploring Titan, specifically a foldable fixed-wing UAV that is folded and placed inside a reentry vehicle. The UAV adopts a conventional aerodynamic layout. Specifically, the tail fin features an anhedral V-tail configuration, the ducted engine is located above the wing near the wing root, the propeller is positioned within the wing boundary layer, and the fuselage employs a rigid shell structure with a foam-core outer skin.

[0009] The fuselage is arranged from front to back with bulkhead 1, bulkhead 2, bulkhead 3, bulkhead 4, and bulkhead 5. Bulkheads 1 and 5 employ a foam sandwich structure. Bulkheads 3 and 4 are reinforced frames to strengthen the fuselage structure. Frame 2 is a standard frame that supports the fuselage's external shape. Simultaneously, transverse bulkheads are installed along the front-rear direction of the fuselage, with their front and rear ends connecting to bulkheads 1 and 5 respectively. These transverse bulkheads support the fuselage's external shape and facilitate internal compartment partitioning.

[0010] The fuselage has two spars, one at the front and one at the rear, arranged along the wing span, and three ribs, rib 1, rib 2, and rib 3, arranged at equal intervals from the wing root to the wingtip. Rib 2 is designed as the wing folding position, which is equipped with a turning and locking mechanism to enable the wing to fold downwards and control its reverse unfolding.

[0011] The V-tail fin folds upward toward the fuselage via a folding locking mechanism installed at the tail, and can also be controlled to unfold in the opposite direction.

[0012] The aforementioned folding fixed-wing UAV is designed for low cruising speed and employs a nuclear-lithium hybrid energy system. It utilizes an RTG (Regenerative Thermal Geography) to power the UAV's onboard equipment and charge the lithium-ion battery. It also provides an operating temperature for the onboard equipment and lithium-ion battery. Power load is balanced through the charging and discharging of the lithium-ion battery, reducing energy waste.

[0013] Furthermore, a combined active and passive thermal management model is adopted. Passive thermal management consists of a foam skin and a foam sandwich structure, which reduces heat loss and improves insulation performance. The airborne heat exchanger operates, ensuring heat dissipation for the RTG while providing the temperature conditions required for the normal operation of the airborne equipment. The adjustable damper adjusts its opening according to the temperature of the equipment compartment to ensure that the airborne equipment operates at a suitable temperature.

[0014] Before launch, the UAV is folded, docked with the reentry vehicle, and all systems and equipment are checked for proper functioning and connections. After folding, the UAV is physically connected to the reentry vehicle via connection points on the reinforcing frame. Considering that the heat shield will be jettisoned first upon entering Titan's atmosphere, the UAV connects to the reentry vehicle via its dorsal side. Simultaneously, during launch, the heat shield faces upwards, and the UAV absorbs thrust through the dorsal connection points.

[0015] During the voyage, the equipment needs to be powered on and self-tested regularly, and a suitable temperature needs to be provided for the equipment. During the voyage, the RTG continuously releases heat, which needs to be transferred to the reentry unit through a heat exchange circuit for heat dissipation. The lithium battery also needs to be charged and discharged regularly.

[0016] Before entering Titan's atmosphere, the unmanned aerial vehicle will conduct a final power-on and self-check in Titan's orbit, complete the lithium battery charging, and start the flight control equipment.

[0017] The reentry vehicle then descended and entered the atmosphere of Titan. It used Titan's dense atmosphere to decelerate, and at an appropriate speed, used a parachute to further slow it down. Once inside Titan's atmosphere, a heat-resistant base protected the drone.

[0018] At an altitude of 15km to 20km, the reentry vehicle descends almost vertically, reducing its speed to 20m / s. It jettisons its heat shield and disconnects the UAV from the reentry vehicle, allowing the UAV to detach. After stabilizing, the UAV completes its deployment-lock maneuver and performs a power-on self-test on its control servos.

[0019] Before release, the drone maintains a nose-down attitude. After release, the elevator is kept deflected downwards, and the torque generated by its own longitudinal stability increases the nose-down torque, reducing the drone's angle of attack. When the drone's angle of attack is less than 18°, the engine increases thrust, and the stick is gradually pulled back, causing the drone to transition from a dive to level flight.

[0020] When the altitude drops to 10km, the UAV is released. After release, the UAV descends while simultaneously reducing its angle of attack, and simultaneously starts its power unit to enter level flight mode. Once in level flight mode, it activates its communication equipment to establish contact with the relay satellite, transmits its status, and receives commands. Afterward, it sequentially completes the self-check and activation of its scientific payload, transitioning to the scientific exploration phase.

[0021] The advantages of this invention are:

[0022] 1. This invention is applicable to unmanned aerial vehicles (UAVs) used for Titan exploration. Through a folding design, they can be housed by a reentry vehicle. The wings fold downwards and the tail fin folds upwards via a tail strut, ensuring that the main load-bearing structures on the back of the UAV fuselage are shielded after folding, allowing it to be accommodated by the reentry vehicle.

[0023] 2. This invention is applicable to unmanned aerial vehicles used for Titan exploration. The ducted motor is located above the wing near the wing root, which effectively improves aerodynamic efficiency. The propeller is arranged within the wing boundary layer, which effectively improves propulsion efficiency.

[0024] 3. This invention is applicable to unmanned aerial vehicles (UAVs) used for Titan exploration. Due to the size constraints of the reentry vehicle, the size of the UAV is limited. The rigid shell structure can ensure the internal space of the UAV within the limited dimensions. The skin uses a foam core, which helps maintain the internal temperature and reduce the structural weight coefficient of the UAV.

[0025] 4. This invention is applicable to unmanned aerial vehicles (UAVs) for exploring Titan. It uses an RTG (Regenerative Thermal Governing Unit) as the primary power source, providing stable and long-term power to enable the UAV to fly normally for extended periods within Titan's extremely cold, oxygen-free, and low-light atmosphere. The hybrid energy system, composed of RTG and lithium-ion batteries, balances the power load, reducing the overall weight of the energy system while improving flight performance and enhancing the UAV's adaptability to complex working environments.

[0026] 5. This invention is applicable to unmanned aerial vehicles for Titan exploration, and adopts a thermal management mode that combines active and passive methods to ensure that the onboard equipment operates at a suitable temperature. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the deployed state structure of the unmanned aerial vehicle applicable to the exploration of Titan according to the present invention;

[0029] Figure 2 This is a schematic diagram of the structural skeleton of the unmanned aerial vehicle applicable to the exploration of Titan according to the present invention;

[0030] Figure 3 This is a schematic diagram of the structural parameters of the unmanned aerial vehicle applicable to the exploration of Titan according to the present invention;

[0031] Figure 4 This is a schematic diagram of the folding structure on the wing of an unmanned aerial vehicle applicable to the exploration of Titan according to the present invention;

[0032] Figure 5 This is a schematic diagram of the inner wing section of the folding structure.

[0033] Figure 6 This is a side view of the outer wing section of the folding structure;

[0034] Figure 7 This is a schematic diagram of the folding structure on the tail support of an unmanned aerial vehicle applicable to the exploration of Titan, according to the present invention.

[0035] Figure 8 This is a schematic diagram of the folded state of the unmanned aerial vehicle (UAV) applicable to the exploration of Titan, as described in this invention, located inside the reentry vehicle.

[0036] Figure 9 This is a schematic diagram of the reentry vehicle structure parameters adapted for the unmanned aerial vehicle used in the exploration of Titan, which is the subject of this invention.

[0037] In the picture:

[0038] 4-Fuselage 501-Outer Wing Section 502-Inner Wing Section 601-Rotating component 602-Pulley A 603-Tenon and Mortise Buckle 604-Traction Rope A 605-Tractor Head 601a-End Mounting Block 601b-Rotary Joint 701-male connector 702-Mother Connector 703-Pulley B 704-Traction Rope B Detailed Implementation

[0040] The present invention will now be described in further detail with reference to the accompanying drawings.

[0041] This invention relates to unmanned aerial vehicles for exploring Titan, and is a folding fixed-wing unmanned aerial vehicle with a conventional aerodynamic layout, such as... Figure 1 As shown. The tail fin 1 adopts an upward-facing V-tail configuration, which is easier to fold than a horizontal or vertical tail, facilitating the storage of the UAV in the reentry vehicle; moreover, the V-tail configuration is lighter than conventional tail fin configurations, helping to reduce the structural weight of the UAV. In addition, the V-tail structure reduces the number of intersecting surfaces of tail fin 1 from three to two, effectively reducing interference drag. The ducted engine 2 is located above wing 3 near the wing root, effectively improving aerodynamic efficiency. The propeller is arranged within the wing boundary layer, utilizing the aerodynamic characteristics of the wing boundary layer to improve propulsion efficiency.

[0042] The UAV's fuselage (4) employs a rigid-shell structure to ensure sufficient internal space within the reentry vehicle's size constraints. The outer skin of the UAV uses a foam sandwich structure, reducing the weight coefficient of the UAV mechanism while ensuring sufficient rigidity. Furthermore, the foam sandwich provides good thermal insulation, forming a heat insulation layer that helps maintain the internal temperature of the UAV cabin to some extent. Figure 2 As shown, the fuselage 4 is equipped with bulkhead 1, bulkhead 2, bulkhead 3, bulkhead 4, and bulkhead 5 sequentially from front to back. Bulkheads 1 and 5 employ a foam sandwich structure to reduce heat loss. Since the wings 3 are installed at the locations of bulkheads 3 and 4, where the fuselage 4 structure experiences significant stress, bulkheads 3 and 4 are reinforced frames to strengthen the fuselage 4 structure at these locations. Frame 2 is a standard frame used to support the shape of the fuselage 4. Transverse bulkheads are also arranged inside the fuselage 4, running along its longitudinal direction, connecting to bulkheads 1 and 5 at their front and rear ends respectively, serving to support the shape of the fuselage 4 and to partition the interior of the unmanned aerial vehicle (UAV). All the aforementioned bulkheads and frames are made of carbon fiber.

[0043] The unmanned aerial vehicle fuselage 4 has two front and rear wing spars arranged along the span of the wing 3 on both sides of the wings 3, and three wing ribs arranged at equal intervals from the wing root to the wing tip: rib 1, rib 2 and rib 3.

[0044] In the aforementioned wing 3, the position of rib 2 is designed as the folding position of wing 3. A turning and locking mechanism is designed at this position to enable wing 3 to fold downwards. Let the two ends of wing 3 on both sides of the folding position be the outer wing section 501 that can fold downwards and the inner wing section 502 that connects to the fuselage 4, respectively; then the specific structure and installation method of the turning and locking mechanism are as follows:

[0045] The turning and locking mechanism includes a rotating component 601, a pulley A602, a tenon and mortise buckle 603, a traction rope A604, and a traction head 605, such as Figure 4 , Figure 5 , Figure 6 As shown.

[0046] The rotating component 601 has a U-shaped structure, including a bottom end mounting block 601a and rotating joints 601b designed on both sides of the front end, such as... Figure 5 As shown. Two rotating parts 601 are fixedly mounted along the spanwise direction to the inner wall of the lower wing surface of the outer wing section 501 via mounting blocks 601a. ​​Multiple tenon-and-mortise fasteners 603 are arranged at equal intervals along the spanwise direction of the wing 3; each tenon-and-mortise fastener 603 includes a male and a female fastener. The male fastener is fixedly mounted on the inner wall of the upper wing surface of the outer wing section 501; the female fastener is mounted in a slot 607 designed on the side wall of wing rib 2, corresponding to the male fastener. Simultaneously, a block-shaped traction head 605 is installed at the center of the inner wing surface of the upper wing surface of the outer wing section 501 for connecting the traction rope A604.

[0047] like Figure 6 As shown, the rotary joints on the two rotating parts 601 are respectively installed in the corresponding slots 606 designed along the chord direction on the bottom surface of the No. 2 wing rib, forming a rotating pair through the connection between the rotating shaft and the slot 606. The male heads of the tenon and mortise buckles 603 are respectively engaged with the female heads of the buckles in the slots 607 on the side wall of the No. 2 wing rib. At the same time, a slot is cut at the center of the top of the No. 2 wing rib, and a pulley A602 is installed in the slot through a rotating shaft; one end of the traction rope A604 is fixedly installed on the traction head 605, and the other end is wound around the pulley A602, further fixed and wound around the rope sheave coaxially fixedly sleeved on the output shaft of the drive motor installed in the inner wing section 502.

[0048] The shaft of pulley A602 is coaxially fixed to the output shaft of the drive motor installed inside wing rib 2, and pulley A602 is driven to rotate by the drive motor. Wing rib 2 is fixedly installed at the docking end of the inner wing section 502.

[0049] like Figure 8 As shown, when the UAV is placed into the reentry vehicle, the wing 3 is rotated downwards by applying external force until the UAV can enter the reentry vehicle. After the UAV is placed in the reentry vehicle, the wing 3 is restricted by the reentry vehicle wall and will not deploy. When the UAV is released, the drive motor controls the traction rope A604 to wind around the pulley A602, and the traction rope A604 pulls the wing 3 upwards, restoring the wing 3 from the folded state to the deployed state. In the deployed state, the male head of the tenon and mortise buckle 603 is fully inserted into the corresponding slot and fixed with the female head. At the same time, the rotary joint 601b on the rotating part 601 is retracted into the insertion slot 606; at this time, the inner wing section 502 and the outer wing section 501 are connected to form an integral wing.

[0050] The aforementioned V-tail fin 1 can be folded upwards towards the fuselage 4 via a folding locking mechanism installed at the tail, with the folding position located 3.2m from the foremost point of the fuselage. For example... Figure 7As shown, the folding locking mechanism includes a male connector 701, a female connector 702, a pulley B703, and a traction rope B704.

[0051] The male connector 701 is a plate-shaped structure, with its end fixedly installed on the front end face of the fuselage 4 at the folded position, arranged along the longitudinal center line of the front end face of the fuselage 4. The female connector 702 consists of two parallel plates, with the ends of the two parallel plates fixedly installed on the front end face of the tail support rod at the rear of the folded position, and the male connector 701 is inserted between the two parallel plates.

[0052] The aforementioned male connector 701 is inserted between the two parallel plates in the female connector 702 and is connected to the female connector 702 via a rotating shaft to form a rotating pair; and the front ends of the male connector 701 and the two female connectors 702 are designed to be arc-shaped to avoid interference with the tail support rod and the end of the fuselage 4 during rotation.

[0053] The male connector 701 has a groove at its bottom, and a pulley B703 is installed in the groove via a rotating shaft. At the same time, a hole is opened at the bottom of the male connector 701, located in front of and near the pulley B703, and this hole communicates with the groove at the bottom of the male connector 701. One end of the traction rope B704 is fixed to a screw fixed below the front end of the tail support rod and is wound around the pulley B703. The other end passes through the through hole opened below the male connector 701 and enters the body 4, where it is fixed to a rope winding wheel that is coaxially fixed to the output shaft of the drive motor installed inside the body 4 and wound around the rope winding wheel.

[0054] like Figure 8 As shown, when the UAV is placed into the reentry vehicle, the V-tail 1 of the above structure rotates upward by applying external force until the wingtip of the V-tail 1 contacts the wing 3. After the UAV is placed in the reentry vehicle, the V-tail 1 is restricted by the reentry vehicle wall and will not deploy. When the UAV is released, the V-tail 1 detaches from the reentry vehicle wall and is no longer restricted by external force. At this time, the drive motor can control the traction rope B704 to wind around the pulley B703, causing the tail support to rotate downward around the pivot between the male connector 701 and the female connector 702, so that the V-tail 1 returns from the folded state to the deployed state. In the deployed state, the axis of the tail support is horizontal at a 180-degree angle to the axis of the fuselage 4. When the tail support is deployed to be parallel to the fuselage 4, the self-locking structure designed between the male connector 701 and the female connector 702 secures the deployed tail support.

[0055] The unmanned aerial vehicle of this invention is stored in a folded state in the reentry vehicle before entering the atmosphere of Titan. For example... Figure 9As shown, the reentry vehicle has an overall height of 1.85m and consists of two parts. The upper part has a flat top surface and a height of 1.05m. Its outer wall has two coaxial conical sections. The upper conical section forms a frustum with a top diameter of 1m, a bottom diameter of 2.9m, and a height of 0.5m. The lower conical section forms a frustum with a bottom diameter of 3.6m, and its top surface is the same as the bottom surface of the upper conical section. The lower part has a flat bottom surface with a diameter of 1.1m. Its outer wall is a conical surface, coaxial with the upper part. The top surface of the conical surface is the bottom surface of the lower part, and the bottom surface of the conical surface is the bottom surface of the lower conical section of the upper part's outer wall. All the conical sections have smooth transitions at their junctions, and the top surface of the upper part and the bottom surface of the lower part also have smooth transitions with the conical surfaces.

[0056] To meet the aforementioned reentry vehicle size requirements and the aerodynamic requirements for Titan exploration, the external dimensional parameters of the unmanned aerial vehicle in its deployed and folded states were designed as follows:

[0057] In its deployed state: Overall length 4.475m, height 1.199m; maximum fuselage width 0.6m; maximum fuselage height 0.63m. Wing area 6.045m². 2 The wingspan is 6.2m, the aspect ratio is 6.36, the tip-to-root ratio is 2, and the quarter-chord sweep angle is 0°. The single tail fin has an area of ​​0.75㎡, a half-span of 1m, a leading-edge sweep angle of 20°, an anhedral angle of 38°, a tip-to-root ratio of 0.67, and a horizontal distance of 3.5m between the leading edge of the tail fin and the leading edge of the nose.

[0058] In its folded state: Maximum length 3.27m, maximum width 3.34m, maximum height 1.77m. Wing folding angle: 150°; Tail folding angle: 150°.

[0059] The distance between bulkhead 1 and the front of fuselage 4 is 0.55m; the distance between bulkhead 1 and bulkhead 2 is 0.505m; the distance between bulkhead 2 and bulkhead 3 is 0.495m; the distance between bulkhead 3 and bulkhead 4, and the distance between bulkhead 4 and bulkhead 5 are both 0.45m. The distance between wing rib 3 and the interwing distance, and the distance between wing rib 2 and wing rib 1, are both 0.75m; the distance between wing rib 1 and wing rib 3 is 0.65m. The folding angle of wing 3 is 150°; the folding angle of tail 1 is 150°.

[0060] The unmanned aerial vehicle of this invention has a relatively slow cruising speed of 5 m / s, a low Reynolds number, and a thick boundary layer. Two ducted engines 2 are positioned above the wing 3 near the wing root. The intake air from the engines exerts a beneficial interference on the wing 3, improving aerodynamic efficiency. The propeller is positioned within the wing boundary layer to improve propeller propulsion efficiency and save energy.

[0061] Meanwhile, the unmanned aerial vehicle of this invention adopts a nuclear-lithium hybrid energy system, utilizing the strong environmental adaptability and stable function of RTG (isotope thermoelectric battery) to power the normal operation of the UAV's onboard equipment and charge the lithium-ion battery; it also provides an acceptable operating temperature for the UAV's onboard equipment and the lithium-ion battery. Energy waste is reduced by balancing the power load through the charging and discharging of the lithium-ion battery.

[0062] Furthermore, a combined active and passive thermal management model is adopted. Passive thermal management consists of a foam skin and a foam sandwich structure, which reduces heat loss and improves insulation performance. The airborne heat exchanger operates, ensuring heat dissipation for the RTG while providing the temperature conditions required for the normal operation of the airborne equipment. The adjustable damper adjusts its opening according to the temperature of the equipment compartment to ensure that the airborne equipment operates at a suitable temperature.

[0063] Due to limitations in reentry vehicle size and rocket payload capacity, the total takeoff weight of the unmanned aerial vehicle (UAV) of this invention does not exceed 250 kg. This allows the UAV to operate normally in the low-gravity, high-atmospheric-density, oxygen-free, low-light, and extremely cold atmosphere of Titan. Table 1 shows the iterative calculations of the UAV's total takeoff weight and the weight distribution of each component, ensuring compliance with rocket payload capacity requirements.

[0064] Table 1. Total takeoff weight of unmanned aerial vehicles and weight percentage of each component

[0065]

[0066] Before launch, the UAV was folded, docked with the reentry vehicle, and all systems and equipment were checked for proper functioning and connections. Considering that the heat shield (lower half of the reentry vehicle) would be jettisoned first upon entering Titan's atmosphere, the folded UAV was connected to the upper half of the reentry vehicle via a rope through a connection point on the reinforcing frame on the back of the UAV's fuselage. Simultaneously, during launch, the heat shield faced upwards, and the UAV absorbed thrust through the connection point on its back.

[0067] Due to the extended flight time, the equipment needs to undergo periodic power-on self-checks and be kept at a suitable temperature during flight. Furthermore, the RTG continuously releases heat during flight, requiring a heat exchange circuit to transfer this heat to the reentry vehicle and other cooling methods to dissipate it, ensuring the drone's safety. Additionally, the lithium battery needs to be periodically charged and discharged during flight to extend its lifespan.

[0068] Before entering Titan's atmosphere, the unmanned aerial vehicle will conduct a final power-on and self-check in Titan's orbit, complete the lithium battery charging, and start the flight control equipment.

[0069] The reentry vehicle then descends and enters the atmosphere of Titan. It utilizes Titan's dense atmosphere for deceleration, and at an appropriate speed, further decelerates using parachutes. Upon entering Titan's atmosphere, the heat shield should not be jettisoned prematurely; instead, it should be used to protect the drone. Because the drone's designed cruising speed is 5 m / s, its structure has limited dynamic pressure tolerance; jettisoning the heat shield too early could damage the drone's structure.

[0070] At an altitude of 15km-20km, the reentry vehicle descends in a near-vertical motion, reducing its speed to 20m / s. It jettisons its heat shield and detaches from the reentry vehicle. At this point, the UAV is connected to the upper part of the reentry vehicle by a cable, creating conditions for the deployment of wings 3 and tail 1. After stabilizing during descent, the UAV completes deployment and locking maneuvers and performs a power-on self-test on its control servos (the V-tail control servos and the wing control surface servos).

[0071] To prevent the UAV from entering a spin and going out of control due to an excessive angle of attack after release, the UAV should be kept nose-down before release. After release, keep the elevator deflected downwards and, using the torque generated by its own longitudinal stability, increase the nose-down torque as much as possible to quickly reduce the UAV's angle of attack. Once the UAV's angle of attack is less than 18°, increase engine thrust and gradually pull back on the stick to control the power system to increase thrust, while adjusting the control surfaces to transition the UAV from a dive to level flight.

[0072] When the altitude decreases to 10km, the drone is released and detaches from the cable. After release, the drone glides down, reducing its angle of attack. Simultaneously, it initiates its power unit and enters level flight. Once in level flight, it activates its communication equipment, establishes contact with the relay satellite, transmits its status, and receives commands. Afterward, it sequentially completes the self-checks and activation of its scientific payload, transitioning to the scientific exploration phase.

[0073] After the drone completes its release and enters cruise flight, it will transition into the scientific exploration phase. This phase will last approximately 180 Earth days.

[0074] To improve detection efficiency, the drones first conduct a broad, general search of Titan from high altitude. When targets of particular scientific value are discovered, the drones then descend for detailed exploration. The drones can also perform "staring" detection on specific targets, creating 3D images through 360-degree scanning for better target detection.

Claims

1. An unmanned aerial vehicle suitable for exploration of Titan, characterized in that: The unmanned aerial vehicle is a folding fixed-wing UAV, which is placed inside the reentry vehicle after folding. The UAV adopts a conventional aerodynamic layout. The tail fin adopts an anhedral V-tail layout, and the ducted engine is located above the wing near the wing root. The propeller is arranged within the wing boundary layer. The fuselage adopts a rigid shell structure, and the outer skin is made of foam sandwich. The fuselage is equipped with bulkhead 1, bulkhead 2, bulkhead 3, bulkhead 4, and bulkhead 5 from front to back. Bulkhead 1 and bulkhead 5 have a foam sandwich structure. Bulkhead 3 and bulkhead 4 are reinforced frames to strengthen the fuselage structure. Bulkhead 2 is a regular frame that supports the fuselage shape. At the same time, transverse bulkheads are set along the front and rear direction of the fuselage inside the fuselage. The front and rear ends of the transverse bulkheads are connected to bulkhead 1 and bulkhead 5, respectively. The transverse bulkheads support the fuselage shape and realize the internal partitioning. The fuselage has two front and rear wing spars arranged along the span of the wings on both sides, and three wing ribs arranged at equal intervals from the wing root to the wingtip: rib 1, rib 2 and rib 3. Rib 2 is designed as the wing folding position. The wing folding position is designed with a turning and locking mechanism to realize the downward folding of the wing and control the reverse unfolding. The V-tail fin folds upward toward the fuselage via a folding locking mechanism installed at the tail, and can also be controlled to unfold in the opposite direction. The folding fixed-wing UAV is designed for low cruising speed and uses a nuclear-lithium hybrid energy system. It utilizes RTG to power the UAV's onboard equipment and charge the lithium-ion battery. It also provides the operating temperature for the UAV's onboard equipment and lithium-ion battery. The power load is balanced by charging and discharging the lithium-ion battery to reduce energy waste. It adopts a combined active and passive thermal management mode. The passive thermal management consists of a foam skin and a foam sandwich structure to reduce heat loss and improve the insulation effect. The airborne heat exchanger works to ensure the heat dissipation of the RTG while providing the temperature conditions required for the normal operation of the airborne equipment. The adjustable damper adjusts the opening size according to the temperature of the equipment compartment to ensure that the airborne equipment operates at a suitable temperature. Before launch, the UAV is folded and docked with the reentry vehicle, and the normal operation and connection of each system and equipment are checked. After folding, the UAV is physically connected to the reentry vehicle through the connection points set on the reinforcing frame. Considering that the heat shield will be jettisoned first after entering Titan's atmosphere, the UAV connects to the reentry vehicle through the back of the fuselage. At the same time, during launch, the heat shield faces upward, and the UAV bears the thrust through the connection points on its back during the launch process. During the voyage, the equipment needs to be powered on and self-tested regularly, and a suitable temperature needs to be provided for the equipment. During the voyage, the RTG continuously releases heat, which needs to be transferred to the reentry unit through a heat exchange circuit for heat dissipation. The lithium battery also needs to be charged and discharged regularly. Before entering Titan's atmosphere, the unmanned aerial vehicle will conduct a final power-on and self-check in Titan's orbit, complete the lithium battery charging, and start the flight control equipment. Subsequently, the reentry vehicle descended and entered the atmosphere of Titan. The reentry vehicle used the dense atmosphere of Titan to decelerate, and at an appropriate speed, it used a parachute to further decelerate. After entering the atmosphere of Titan, the heat shield was used to protect the drone. At an altitude of 15km to 20km, the reentry vehicle descends vertically, reducing its speed to 20m / s, and jettisons its heat shield. At this point, the UAV is connected to the upper part of the reentry vehicle via a rope. After the descent stabilizes, the UAV completes the deployment-locking maneuver and performs a power-on self-test on the control servos. Before release, the drone maintains a nose-down attitude; after release, the elevator is kept tilted down, and the torque generated by its own longitudinal stability is used to increase the nose-down torque and reduce the drone's angle of attack; when the drone's angle of attack is less than 18°, the engine increases thrust and the stick is gradually pulled back to bring the drone from a dive to a level flight. When the altitude drops to 10km, the UAV is released. After release, the UAV descends while reducing its angle of attack. At the same time, it starts its power unit and enters level flight cruise mode. After entering level flight mode, it starts its communication equipment, establishes contact with the relay satellite, sends its own status, and receives instructions. Then, it completes the self-check and startup of its scientific payload in sequence and enters the scientific exploration phase.

2. The unmanned aerial vehicle suitable for Titan exploration as described in claim 1, characterized in that: The specific structure and installation method of the turning and locking mechanism are as follows: Let the wings on both sides of the folding position be the downward-folding outer wing section and the inner wing section connected to the fuselage, respectively; then the turning and locking mechanism includes a rotating component, pulley A, tenon and mortise buckles, traction rope A, and traction head; wherein, the rotating component is a U-shaped structure, including a mounting block at the bottom end and rotating joints designed on both sides of the front end; the rotating component is fixedly installed along the spanwise direction on the middle of the inner wall of the lower wing surface of the outer wing section docking end through the mounting block; the tenon and mortise buckles are evenly spaced along the spanwise direction of the wing; the tenon and mortise buckles include a male buckle head and a female buckle head; wherein, the male buckle head is fixedly installed on the inner wall of the upper wing surface of the outer wing section docking end; the female buckle head is installed on the side wall of wing rib No. 2 at the position corresponding to the male buckle head. Inside the slot; at the same time, a block-shaped traction head is installed at the center of the inner surface of the outer wing section docking end for connecting traction rope A; the rotary joints on the rotating parts are respectively installed in the corresponding slots designed along the chord direction on the bottom surface of wing rib No. 2, forming a rotating pair through the connection between the rotating shaft and the slot; the male buckle of the tenon and mortise buckle is respectively engaged with the female buckle in the slot on the side wall of wing rib No. 2; at the same time, a slot is cut at the center of the top of wing rib No. 2, and a pulley A is installed in the slot through the rotating shaft; one end of traction rope A is fixedly installed on the traction head, and the other end is wound around the pulley A, further fixed and wound around the rope sheave coaxially fixedly sleeved on the output shaft of the drive motor installed in the inner wing section.

3. The unmanned aerial vehicle suitable for Titan exploration as described in claim 2, characterized in that: When the UAV is placed into the reentry vehicle, the wing is rotated downwards by applying external force until the UAV can enter the reentry vehicle. After the UAV is placed in the reentry vehicle, the wing is restricted by the reentry vehicle wall and will not unfold. When the UAV is released, the drive motor controls the traction rope A to wind around the pulley A, and the traction rope A pulls the wing upwards to restore the wing from the folded state to the unfolded state. In the unfolded state, the male head of the tenon and mortise buckle is fully inserted into the corresponding slot and fixed with the female head of the tenon and mortise buckle. At the same time, the rotary joint on the rotating part is retracted into the slot. At this time, the inner wing section and the outer wing section are connected to form an integral wing.

4. The unmanned aerial vehicle suitable for Titan exploration as described in claim 1, characterized in that: The folding locking mechanism includes a female connector, a male connector, a pulley B, and a traction rope B. The male connector is a plate-shaped structure, with its end fixedly installed on the front end face of the fuselage at the folding position, arranged along the longitudinal centerline of the fuselage end face. The female connector consists of two parallel plates, with their ends fixedly installed on the front end face of the tail support rod at the rear of the folding position. The male connector is inserted between the two parallel plates in the female connector and connected to the female connector via a rotating shaft to form a rotating pair. The male connector has a groove at its bottom, and a pulley B is installed in the groove via a rotating shaft. At the same time, a hole is opened at the bottom of the male connector, in front of and near the pulley B, and the hole communicates with the groove at the bottom of the male connector. One end of the traction rope B is fixed to a screw fixed below the front end of the tail support rod and is wound around the pulley B. The other end passes through the through hole opened below the male connector and enters the machine body, where it is fixed and wound around a rope-winding wheel that is coaxially fixed to the output shaft of the drive motor installed inside the machine body.

5. The unmanned aerial vehicle suitable for Titan exploration as described in claim 4, characterized in that: When the UAV is placed into the reentry vehicle, an external force is applied to rotate the tail boom upwards until the V-tail tip contacts the wing. After the UAV is placed in the reentry vehicle, the V-tail is restricted by the reentry vehicle wall and will not deploy. When the UAV is released, the V-tail detaches from the reentry vehicle wall and is no longer restricted by external force. At this time, the drive motor can control the traction rope B to wind around the pulley B, causing the tail boom to rotate downwards around the pivot between the connector head and the connector female head, so that the V-tail returns from the folded state to the deployed state. In the deployed state, the tail boom axis is horizontal at a 180-degree angle with the fuselage axis. When the tail boom is deployed to be parallel to the fuselage, the self-locking structure designed between the connector head and the connector female head is used to fix the tail boom after deployment.

6. The unmanned aerial vehicle suitable for Titan exploration as described in claim 1, characterized in that: The reentry vehicle has an overall height of 1.85m and consists of two parts: the upper part has a flat top surface and a height of 1.05m; the outer wall of the upper part has two coaxial conical surfaces, the upper conical surface forming a frustum with a top diameter of 1m, a bottom diameter of 2.9m, and a height of 0.5m; the lower conical surface forming a frustum with a bottom diameter of 3.6m, and its top surface is the bottom surface of the frustum formed by the upper conical surface; the bottom surface of the lower part is a flat plane with a diameter of 1.1m; the outer wall of the lower part is a conical surface, coaxial with the upper part; the top surface of the conical surface is the bottom surface of the lower part, and the bottom surface of the conical surface is the bottom surface of the lower conical surface of the outer wall of the upper part. To meet the size requirements of the reentry vehicle and the aerodynamic requirements of the Titan exploration mission, the unmanned aerial vehicle (UAV) was designed with the following dimensions in its deployed state: overall length 4.475m, height 1.199m; maximum fuselage width 0.6m; maximum fuselage height 0.63m; wing area 6.045m². 2 The wingspan is 6.2m, the aspect ratio is 6.36, the tip-to-root ratio is 2, and the 1 / 4 chord sweep angle is 0deg; the single tail fin area is 0.75㎡, the tail fin half-span is 1m, the tail fin leading edge sweep angle is 20deg, the tail fin dihedral angle is 38deg, the tail fin tip-to-root ratio is 0.67, and the horizontal distance between the leading edge of the tail fin and the leading edge of the nose is 3.5m. In the folded state: the maximum length of the aircraft is 3.27m, the maximum width is 3.34m, and the maximum height is 1.77m; the wing folding angle is 150°; the tail folding angle is 150°; the tail folding position is 3.2m from the front of the fuselage. The distance between bulkhead 1 and the front of the fuselage is 0.55m; the distance between bulkhead 1 and bulkhead 2 is 0.505m; the distance between bulkhead 2 and bulkhead 3 is 0.495m; the distance between bulkhead 3 and bulkhead 4, and the distance between bulkhead 4 and bulkhead 5 are all 0.45m; the distance between wing rib 3 and the interwing distance, and the distance between wing rib 2 and wing rib 1 are all 0.75m; the distance between wing rib 1 and wing rib 3 is 0.65m; the wing folding angle is 150°; the tail fin 1 folding angle is 150°.

7. The unmanned aerial vehicle suitable for Titan exploration as described in claim 6, characterized in that: The total takeoff weight is no more than 250 kg; the mission payload is 25.00 kg; the onboard equipment is 60.00 kg; the environmental control equipment is 10.00 kg; the airframe structure is 56.46 kg; the RTG is 70.30 kg; the propulsion motor is 0.08 kg; and the lithium-ion battery is 4.00 kg.

8. The unmanned aerial vehicle suitable for Titan exploration as described in claim 6, characterized in that: Partition No. 1, Partition No. 2, Partition No. 3, Partition No. 4 and Partition No. 5 are all made of carbon fiber.

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