An unmanned aerial vehicle deicing system and method that automatically adjusts the sun direction in combination with a phase change energy storage auxiliary fuel tank and a light-heat coating

Abstract

This invention relates to the field of drone wing de-icing, specifically to a drone de-icing system and method that automatically adjusts the sun-facing direction by combining a phase change energy storage auxiliary fuel tank and a photothermal coating. The system includes a photothermal coating, a loop heat pipe system, an icing detection system, an auxiliary fuel tank, and an automatic solar tracking system. The photothermal coating covers the wing surface to absorb sunlight and convert it into heat energy. The loop heat pipe system consists of an evaporation section, a compensation chamber, and a condensation section, connected by pipelines. The automatic solar tracking system detects the solar azimuth and altitude angles, and, in conjunction with the flight system, controls the flight angle to achieve optimal sunlight intensity and increase the absorption of photothermal energy. The phase change material in the auxiliary fuel tank stores heat from the wing surface through the loop heat pipe. When icing occurs on the wing surface, the loop heat pipe system extracts heat from the phase change material and fuel to achieve de-icing. This invention reduces power consumption while ensuring effective de-icing, thus guaranteeing the drone's endurance.

Description

Technical Field

[0001] This invention relates to an anti-icing system and method for unmanned aerial vehicles (UAVs) that combines a phase change energy storage auxiliary fuel tank with a photothermal coating and can automatically adjust the sun-facing direction, belonging to the field of anti-icing for UAV wings. Background Technology

[0002] When an aircraft flies at a speed below the critical Mach number, its wings, engine air intakes, and other components collide with supercooled droplets in the atmosphere, causing icing. Drones, being small and carrying limited fuel or electrical energy, have even shorter response times when encountering icing stalls. Statistics show that icing is responsible for 25% of drone crashes. Currently, most drones use engine bleed air combined with electric heating for de-icing, a method that is not only energy-intensive but also affects engine thrust, significantly impacting drone performance. Therefore, there is an urgent need to develop low-energy, high-efficiency de-icing technology suitable for drones to ensure flight safety.

[0003] Several patents have proposed anti-icing technologies and applications for drones. Patent CN110979693A designs an engine bleed air anti-icing system for drones, its main feature being the use of engine bleed air supplemented by a gas collection device, effectively solving the problem of wing icing in cold and humid environments. However, this patent uses engine bleed air for anti-icing, and drones generally use piston engines with relatively low power. Using engine bleed air for anti-icing reduces engine thrust, resulting in insufficient engine power. Patent CN214566187U designs an electrothermal anti-icing system for drones, its main features being a distributed power distribution box, control box, and electrothermal module, enabling independent anti-icing control for different areas of the wings and tail, addressing the anti-icing control needs under different flight conditions. However, the electrothermal anti-icing system converts electrical energy into heat energy, resulting in high energy consumption and a large system mass, placing a significant load on the aircraft and severely impacting the drone's endurance.

[0004] This invention proposes an automatically adjustable solar-facing anti-icing system for unmanned aerial vehicles (UAVs) that combines a phase-change energy storage auxiliary fuel tank with a photothermal coating. The photothermal coating absorbs sunlight during flight and transfers the heat energy to a phase-change energy storage chamber in the auxiliary fuel tank beneath the wing via a loop heat pipe system. Furthermore, an automatic solar tracking system adjusts the flight angle to maintain the aircraft under optimal sunlight intensity. This invention utilizes photothermal technology for anti-icing, significantly reducing the energy consumption of the aircraft system while also possessing broad applicability. Summary of the Invention

[0005] The purpose of this invention is to design an anti-icing and de-icing system for unmanned aerial vehicles (UAVs) that combines a phase change energy storage auxiliary fuel tank with a photothermal coating and can automatically adjust the sun-facing direction. This invention helps to promote the integration of various anti-icing and de-icing technologies and accelerate the application of photothermal energy storage technology for anti-icing and de-icing.

[0006] This application provides an embodiment of an anti-icing and de-icing system for unmanned aerial vehicles (UAVs) that combines a phase change energy storage auxiliary fuel tank with a photothermal coating and can automatically adjust its sun-facing direction. It consists of an automatic solar tracking system 4, a loop heat pipe system, a photothermal coating 1, an auxiliary fuel tank 3, and an icing detector 2.

[0007] The loop heat pipe system includes an evaporator section 6, a condenser section 8, a compensation chamber 7, an evaporator line 5-2, and a condenser line 5-1. The compensation chamber 7 has two interfaces: its right inlet connects to the condenser line 5-1, and its left outlet connects to the evaporator section 6. The evaporator section 6 has two interfaces: its right inlet connects to the left outlet of the compensation chamber 7, and its left outlet connects to the inlet of the evaporator line 5-2. The evaporator line 5-2 has two interfaces: its inlet connects to the left outlet of the evaporator section 6. The outlet of evaporator line 5-2 is connected to the inlet of condenser section 8; condenser section 8 has two interfaces, one of which is connected to evaporator line 5-2 and the other of which is connected to condenser line 5-1; condenser line 5-1 has two interfaces, one of which is connected to condenser line 5-1 and the other of which is connected to compensation chamber 7; evaporator section 6 is close to the inner side of the aircraft wing skin, and condenser section 8 is installed in phase change energy storage cavity 3-12 of auxiliary fuel tank 3 under the wing and is wrapped with phase change material;

[0008] The aircraft has a first auxiliary fuel tank 3-1 and a second auxiliary fuel tank 3-2 on both sides of the wing. The first auxiliary fuel tank 3-1 consists of a fuel chamber 3-11 and a phase change energy storage chamber 3-12. The first auxiliary fuel tank 3-1 has a multi-layer structure. The fuel chamber 3-11 is the spacer between the outer shell of the first auxiliary fuel tank 3-1 and the outer wall of the phase change energy storage chamber 3-12. The first auxiliary fuel tank 3-1 is installed on the underside of the wing via a lifting beam 9-1. The second auxiliary fuel tank 3-2 has the same structure as the first fuel tank 3-1.

[0009] The photothermal coating 1 is uniformly applied to the wing skin;

[0010] The icing detector 2 is an embedded fiber optic detector, which is installed on the surface of the UAV body 10.

[0011] The automatic solar tracking system 4 is installed on both sides of the wing and includes eight photoresistors, which are respectively distributed on the right wing as the first north-facing photoresistor 4-1, the first east-facing photoresistor 4-2, the first south-facing photoresistor 4-3, and the first west-facing photoresistor 4-4, and on the left wing as the second north-facing photoresistor 4-5, the second east-facing photoresistor 4-6, the second south-facing photoresistor 4-7, and the second west-facing photoresistor 4-8, for east-west azimuth tracking and north-south altitude tracking.

[0012] Furthermore, the photothermal coating material is Ti2O3.

[0013] Furthermore, the phase change energy storage chamber 3-12 in the auxiliary fuel tank 3, which encloses the condensation section 8, is used to absorb the heat released by the condensation and liquefaction after entering the condensation section 8 through the evaporation pipeline 5-2. The fuel in the fuel chamber 3-11 can further provide energy storage to the phase change energy storage chamber 3-12.

[0014] Furthermore, the auxiliary oil tank 3 is made of aluminum alloy, and the phase change material in the phase change energy storage cavity 3-12 is CaCl2·6H2O / EG, with a phase change temperature of 29.01℃ and a latent heat of phase change of 151.6kJ / kg.

[0015] Furthermore, the core material of the loop heat pipe system is sintered CuO powder; the evaporation line 5-2, condensation line 5-1, evaporation section 6, compensation chamber 7, and condensation section 8 of the loop heat pipe are made of stainless steel, and the working fluid of the loop heat pipe is liquid ammonia.

[0016] Furthermore, the condensation section 8 of the loop heat pipe system is placed in the phase change energy storage cavity 3-12. When the loop heat pipe system is performing anti-icing and de-icing operations, the heat source is provided by the phase change energy storage cavity 3-12.

[0017] The automatic solar tracking system employs two strategies:

[0018] When the light intensity is greater than or equal to 400 Lux:

[0019] During flight, the north-facing photoresistors 4-1, east-facing photoresistors 4-2, south-facing photoresistors 4-3, and west-facing photoresistors 4-4, installed on the wing surface, are exposed to sunlight. The circuit is controlled by utilizing the characteristic that photoresistors generate photocurrent when exposed to light. The circuit determines whether the photoresistors are exposed to light to determine the direction and calculates the yaw angle, roll angle, and pitch angle that the UAV needs to adjust to maintain the optimal light intensity. The adjustment is made in conjunction with the UAV's flight system, and continuous photoelectric detection is used to continuously adjust the yaw angle, roll angle, and pitch angle to maintain the UAV's flight angle at the optimal light intensity.

[0020] When the light intensity is less than 400 Lux:

[0021] During flight, the photoelectric sensor is turned off. At this time, the positioning system obtains the current time, local longitude and latitude data, and calculates the current solar altitude angle and azimuth angle using the formulas for calculating solar altitude angle and azimuth angle. By linking with the UAV flight system, the yaw angle, roll angle and pitch angle are adjusted to achieve the solar altitude angle and azimuth angle with the best light intensity.

[0022] The loop heat pipe system has two operating strategies:

[0023] When the wing surface temperature is higher than the temperature of the phase change material in the auxiliary fuel tank, the loop heat pipe system stores heat in the phase change energy storage chamber:

[0024] When sunlight shines on the surface of the photothermal coating 1, the photothermal coating 1 converts light energy into heat energy and transfers heat through the aircraft skin. The evaporation section 6 of the loop heat pipe absorbs heat, and the working fluid vaporizes and is heated to form steam. The working fluid is driven by the capillary force of the heat pipe core to leave the evaporation section 6 and enter the evaporation line 5-2. After passing through the evaporation line 5-2, the working steam enters the condensation section 8, liquefies and releases heat to form a subcooled liquid. The solid-liquid phase change material CaCl2·6H2O / EG in the phase change energy storage chamber 3-12 absorbs heat and liquefies at 29.01℃. At this time, the phase change absorbs a large amount of heat. When the temperature of the phase change energy storage chamber 3-12 is higher than that of the fuel chamber 3-11, the fuel in the fuel chamber 3-11 will absorb the heat energy from the phase change energy storage chamber 3-12, using the fuel chamber 3-11 as an additional heat source. The subcooled liquid leaves the condensation section 8 and enters the condensation line 5-1. After passing through the condensation line 5-1, it enters the compensation chamber 7, mixes with the remaining working liquid in the compensation chamber 7, and returns to the evaporation section 6 to complete one cycle.

[0025] When the wing surface temperature is lower than the temperature of the phase change material in the auxiliary fuel tank, the loop heat pipe system transfers heat to the wing surface:

[0026] At this time, in the heat pipe condensation section 8 of the heating circuit of the solid-liquid phase change material CaCl2·6H2O / EG in the phase change energy storage cavity 3-12, CaCl2·6H2O / EG rapidly releases heat and crystallizes, releasing latent heat and solidifying at 29.01℃. At this time, the phase change releases a large amount of heat. When the temperature of the phase change energy storage cavity 3-12 is lower than that of the fuel cavity 3-11, the fuel in the fuel cavity 3-11 transfers the stored heat to the phase change energy storage cavity 3-12, providing further heat for de-icing. The working fluid absorbs heat to form steam, which enters the evaporation section 6 through the evaporation pipe 5-2. The steam releases heat in the evaporation section 6, heats the wing surface skin, and then condenses to form a subcooled fluid. Driven by the capillary force of the heat pipe core, the fluid leaves the evaporation section 6 and enters the compensation chamber 7. After mixing with the residual fluid in the compensation chamber 7, it returns to the condensation section 8 through the condensation pipe 5-1 to complete one cycle. Attached Figure Description

[0027] Appendix Figure 1 A 3D view of the drone;

[0028] Appendix Figure 1The labels in the table are as follows: 1. Photothermal coating, 2. Icing detector, 3-1. First auxiliary fuel tank, 3-2. Second auxiliary fuel tank, 4-1. First north-facing photoresistor, 4-2. First east-facing photoresistor, 4-3. First south-facing photoresistor, 4-4. First west-facing photoresistor, 4-5. Second north-facing photoresistor, 4-6. Second east-facing photoresistor, 4-7. Second south-facing photoresistor, 4-8. Second west-facing photoresistor, 10. UAV body.

[0029] Appendix Figure 2 This is a front view of the drone.

[0030] Appendix Figure 2 The labels in the table are: 3-1. First auxiliary fuel tank, 3-2. Second auxiliary fuel tank, 10. UAV body.

[0031] Appendix Figure 3 A plan view of the drone's wing surface;

[0032] Appendix Figure 3 The following are the label names: 1. Photothermal coating, 2. Icing detector, 3-1. First auxiliary fuel tank, 3-2. Second auxiliary fuel tank, 4. Automatic solar tracking system, 4-1. First north-facing photoresistor, 4-2. First east-facing photoresistor, 4-3. First south-facing photoresistor, 4-4. First west-facing photoresistor, 4-5. Second north-facing photoresistor, 4-6. Second east-facing photoresistor, 4-7. Second south-facing photoresistor, 4-8. Second west-facing photoresistor, 10. UAV body.

[0033] Appendix Figure 4 This is a plan view of the left-wing loop heat pipe system.

[0034] Appendix Figure 4 The labels in the diagram are: 5-1. Condensation line, 5-2. Evaporation line, 6. Evaporation section, 7. Compensation chamber.

[0035] Appendix Figure 5 This is a sectional view of the auxiliary fuel tank;

[0036] Appendix Figure 5 The labels in the text are: 9-1. Lifting beam, 8. Condensation section, 3-12. Phase change energy storage chamber, 3-11. Fuel chamber.

[0037] Appendix Figure 6 A flowchart of a drone anti-icing and de-icing system that combines a phase change energy storage auxiliary fuel tank with a photothermal coating and can automatically adjust its orientation towards the sun. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0039] Example 1: Heat storage process when light intensity is greater than or equal to 400 Lux:

[0040] During the drone's flight, when the light intensity is greater than or equal to 400 Lux, the photoresistors installed on the wings—north-facing photoresistor 4-1, east-facing photoresistor 4-2, south-facing photoresistor 4-3, and west-facing photoresistor 4-4—are exposed to sunlight, generating photocurrents that activate the control circuit. The different voltages generated by the photoresistors allow the control circuit to calculate the yaw angle, roll angle, and pitch angle required for the drone to maintain optimal light intensity. Through feedback adjustment, the solar-facing direction of the drone body 10 is continuously adjusted to maintain the optimal light intensity. After being exposed to sunlight, the surface of the drone's photothermal coating 1 converts light energy into heat energy, which is then transferred through the aircraft skin. The evaporation section 6 of the loop heat pipe absorbs heat from the wing skin, and the working fluid is heated to form steam. Through capillary action, the working fluid leaves the evaporation section 6 and enters the evaporation line 5-2. After passing through the evaporation line 5-2, the working steam enters the condensation section 8, liquefies and releases heat to form a subcooled liquid. The solid-liquid phase change material CaCl2·6H2O / EG in the phase change energy storage chamber 3-12 absorbs heat and liquefies. At this time, the phase change absorbs a large amount of heat. The subcooled liquid leaves the condensation section 8 and enters the condensation line 5-1. After passing through the condensation line 5-1, it enters the compensation chamber 7, mixes with the remaining working liquid in the compensation chamber 7, and returns to the evaporation section 6 to complete one cycle.

[0041] Example 2: Heat storage process when light intensity is less than 400 Lux:

[0042] During the drone's flight, when the light intensity is less than 400 Lux, the photoresistors installed on the wing surface are turned off. The drone's onboard positioning system obtains the current time and latitude / longitude information, and calculates the current altitude and azimuth angles using formulas for solar altitude and azimuth. This information is then linked to the flight system to control and adjust the yaw, roll, and pitch angles, ensuring the drone body 10 reaches the optimal angle towards the sun. When the drone's photothermal coating 1 is exposed to sunlight, the light energy is converted into heat energy and transferred through the aircraft skin. The evaporation section 6 of the loop heat pipe absorbs heat from the wing skin, and the working fluid is heated to form steam. Through capillary action, the working fluid leaves the evaporation section 6 and enters the evaporation line 5-2. After passing through the evaporation line 5-2, the working steam enters the condensation section 8, liquefies and releases heat to form a subcooled liquid. The solid-liquid phase change material CaCl2·6H2O / EG in the phase change energy storage chamber 3-12 absorbs heat and liquefies. At this time, the phase change absorbs a large amount of heat. The subcooled liquid leaves the condensation section 8 and enters the condensation line 5-1. After passing through the condensation line 5-1, it enters the compensation chamber 7, mixes with the remaining working liquid in the compensation chamber 7, and returns to the evaporation section 6 to complete one cycle.

[0043] Example 3: Heat storage process when the phase change energy storage chamber temperature is higher than that of the fuel chamber:

[0044] When the temperature of the phase change energy storage chamber 3-12 is higher than that of the fuel chamber 3-11, the fuel in the fuel chamber 3-11 absorbs the heat energy from the phase change energy storage chamber 3-12, and uses the fuel chamber 3-11 as an additional heat source for de-icing of the loop heat pipe system.

[0045] Example 4: Heat storage process when the phase change energy storage chamber temperature is lower than that of the fuel chamber:

[0046] When the temperature of the phase change energy storage chamber 3-12 is lower than that of the fuel chamber 3-11, the fuel in the fuel chamber 3-11 will transfer the stored heat to the phase change energy storage chamber 3-12, providing further heat for de-icing.

[0047] Example 5: Anti-icing and de-icing process of the loop heat pipe system:

[0048] When the UAV passes through an icing zone during flight, the icing detector 2 is coupled with the control circuit in the loop heat pipe system. The embedded fiber optic icing detection device installed on the wing detects ice crystals forming on the wing surface and transmits an activation command to the loop heat pipe system through the control circuit, activating the loop heat pipe anti-icing system. At this time, the condensing section 8 of the loop heat pipe, which is encased in the phase change energy storage cavity 3-12, begins to absorb the heat from the phase change material CaCl2·6H2O / EG in the phase change energy storage cavity 3-12. After the CaCl2·6H2O / EG temperature decreases and undergoes a phase change, it releases a large amount of latent heat. The working liquid in the condensing section 8 absorbs a large amount of heat and evaporates. Under the capillary force of the porous medium in the core, it flows through the evaporation pipeline 5-2 to the evaporation section 6. When passing through the evaporation section 6, the working liquid liquefies and releases a large amount of latent heat, heating the evaporation section 6. The evaporation section 6 heats the aircraft wing skin that is in close contact with the wing. After the aircraft wing is heated, the ice on the wing surface melts, achieving the de-icing effect. The working fluid, liquefied in the evaporation section 6, mixes with the liquid in the compensation chamber 7 and returns to the condensation section 8 via the condensation line 5-1. The loop heat pipe completes one cycle to achieve de-icing.

[0049] This UAV anti-icing and de-icing system, which combines a phase change energy storage auxiliary fuel tank with a photothermal coating and can automatically adjust its orientation to the sun, utilizes the photothermal coating and the aircraft's auxiliary fuel tank with a phase change energy storage cavity to save energy for the aircraft system. At the same time, by incorporating loop heat pipe technology, it can maintain a good anti-icing and de-icing effect thanks to efficient heat exchange. The system is also equipped with a photoresistor, which adjusts the yaw angle, roll angle, and pitch angle through cascading control with the flight control system to maintain the optimal light intensity. This invention promotes the application of photothermal energy storage in UAVs while solving the problem of huge energy consumption in UAV anti-icing and de-icing systems.

Claims

1. A drone anti-icing and de-icing system that combines a phase change energy storage auxiliary fuel tank and a photothermal coating, characterized in that: The system consists of an automatic solar tracking system (4), a loop heat pipe system, a photothermal coating (1), an auxiliary fuel tank (3), and an icing detector (2). composition: The loop heat pipe system includes an evaporation section (6), a condensation section (8), a compensation chamber (7), an evaporation line (5-2), and a condensation line (5-1). The compensation chamber (7) has two interfaces: the right inlet of the compensation chamber (7) is connected to the condensation line (5-1), and the left outlet of the compensation chamber (7) is connected to the evaporation section (6). The evaporation section (6) has two interfaces: the right inlet of the evaporation section (6) is connected to the left outlet of the compensation chamber (7), and the left outlet of the evaporation section (6) is connected to the inlet of the evaporation line (5-2). The evaporation line (5-2) has two interfaces: the inlet of the evaporation line (5-2) is connected to the left outlet of the evaporation section (6). The side outlet is connected, and the outlet of the evaporation pipeline (5-2) is connected to the inlet of the condensation section (8); the condensation section (8) has two interfaces, in which the inlet of the condensation section (8) is connected to the evaporation pipeline (5-2), and the outlet of the condensation section (8) is connected to the inlet of the condensation pipeline (5-1); the condensation pipeline (5-1) has two interfaces, in which the inlet of the condensation pipeline (5-1) is connected to the outlet of the condensation section (8), and the outlet of the condensation pipeline (5-1) is connected to the compensation chamber (7); the evaporation section (6) is close to the inner side of the aircraft wing skin, and the condensation section (8) is installed in the phase change energy storage cavity (3-12) of the auxiliary fuel tank (3) under the wing and is wrapped with phase change material; The aircraft has a first auxiliary fuel tank (3-1) and a second auxiliary fuel tank (3-2) on the left and right sides of the wing. The first auxiliary fuel tank (3-1) consists of a fuel chamber (3-11) and a phase change energy storage chamber (3-12). The first auxiliary fuel tank (3-1) has a multi-layer structure. The spacer between the outer shell of the first auxiliary fuel tank (3-1) and the outer wall of the phase change energy storage chamber (3-12) is the fuel chamber (3-11). The first auxiliary fuel tank (3-1) is installed on the underside of the wing via a lifting beam (9-1). The second auxiliary fuel tank (3-2) has the same structure as the first auxiliary fuel tank (3-1). The photothermal coating (1) is uniformly applied to the wing skin; The icing detector (2) is an embedded fiber optic detector, which is installed on the surface of the UAV body (10); The automatic solar tracking system (4) is installed on both sides of the wing and includes eight photoresistors, which are respectively distributed on the right wing as the first north-facing photoresistor (4-1), the first east-facing photoresistor (4-2), the first south-facing photoresistor (4-3), and the first west-facing photoresistor (4-4) on the right wing and on the left wing as the second north-facing photoresistor (4-5), the second east-facing photoresistor (4-6), the second south-facing photoresistor (4-7), and the second west-facing photoresistor (4-8), for east-west azimuth tracking and north-south altitude tracking.

2. The unmanned aerial vehicle de-icing system with automatically adjustable sun direction of combination of phase change material auxiliary fuel tank and photothermal coating according to claim 1, characterized in that: The photothermal coating material is Ti2O3.

3. The UAV anti-icing and de-icing system with automatically adjustable sun-facing direction, combining a phase change energy storage auxiliary fuel tank and a photothermal coating as described in claim 1, is characterized in that: The phase change energy storage chamber (3-12) in the auxiliary oil tank (3) encloses the condensation section (8) and is used to absorb the heat released by the condensation and liquefaction after entering the condensation section (8) through the evaporation pipeline (5-2). The fuel in the fuel chamber (3-11) further provides energy storage to the phase change energy storage chamber (3-12).

4. The UAV anti-icing and de-icing system with automatically adjustable sun-facing direction, combining a phase change energy storage auxiliary fuel tank and a photothermal coating as described in claim 1, is characterized in that: The auxiliary oil tank (3) is made of aluminum alloy, and the phase change material in the phase change energy storage cavity (3-12) is CaCl2·6H2O / EG, with a phase change temperature of 29.01℃ and a phase change latent heat of 151.6kJ / kg.

5. The UAV anti-icing and de-icing system with automatically adjustable sun-facing direction, combining a phase change energy storage auxiliary fuel tank and a photothermal coating as described in claim 1, is characterized in that: The core material of the loop heat pipe system is sintered CuO powder; The evaporation line (5-2), condensation line (5-1), evaporation section (6), compensation chamber (7), and condensation section (8) of the loop heat pipe are made of stainless steel, and the working fluid of the loop heat pipe is liquid ammonia.

6. The UAV anti-icing and de-icing system with automatically adjustable sun-facing direction, combining a phase change energy storage auxiliary fuel tank and a photothermal coating as described in claim 1, is characterized in that: The condenser section (8) of the loop heat pipe system is placed in the phase change energy storage cavity (3-12). When the loop heat pipe system is performing anti-icing operations, the heat source is provided by the phase change energy storage cavity (3-12).

7. The method for an automatically adjustable sun-facing anti-icing system for unmanned aerial vehicles (UAVs) combining a phase-change energy storage auxiliary fuel tank and a photothermal coating as described in claim 1, characterized in that: The automatic solar tracking system employs two strategies: When the light intensity is greater than or equal to 400 Lux: During flight, the north-facing photoresistors (4-1), east-facing photoresistors (4-2), south-facing photoresistors (4-3), and west-facing photoresistors (4-4) installed on the wing surface are exposed to sunlight. The control circuit utilizes the characteristic that photoresistors generate photocurrent when exposed to light to control the circuit. The photoresistors compare the incident angle of the sunlight with the light intensity and calculate the yaw angle, roll angle, and pitch angle that the UAV needs to adjust to maintain the optimal light intensity. The adjustment is made in conjunction with the UAV's flight system. Furthermore, the yaw angle, roll angle, and pitch angle are continuously adjusted through photoelectric detection to maintain the UAV's flight angle at the angle of optimal light intensity. When the light intensity is less than 400 Lux: During flight, the photoresistor is turned off. At this time, the positioning system obtains the current time, local longitude, and latitude data, and calculates the current solar altitude angle and azimuth angle using the formulas for calculating solar altitude angle and azimuth angle. The yaw angle, roll angle, and pitch angle are adjusted through the cascading control of the UAV flight system to achieve the solar altitude angle and azimuth angle with the optimal light intensity.

8. The method for an automatically adjustable sun-facing anti-icing system for unmanned aerial vehicles (UAVs) combining a phase-change energy storage auxiliary fuel tank and a photothermal coating as described in claim 7, characterized in that: The loop heat pipe system has two operating strategies; When the wing surface temperature is higher than the temperature of the phase change material in the auxiliary fuel tank, the loop heat pipe system stores heat in the phase change energy storage chamber: When sunlight shines on the surface of the photothermal coating (1), the photothermal coating (1) converts light energy into heat energy and transfers heat through the aircraft skin. The evaporation section (6) of the loop heat pipe absorbs heat, and the working fluid vaporizes and is heated to form steam. Through the capillary force of the heat pipe core, the working fluid is driven to leave the evaporation section (6) and enter the evaporation line (5-2). After passing through the evaporation line (5-2), the working steam enters the condensation section (8), liquefies and releases heat to form a subcooled liquid. The solid-liquid phase change material CaCl2·6H2O / EG in the phase change energy storage cavity (3-12) absorbs heat. At 29.01℃, phase change liquefaction occurs. At this time, the phase change absorbs a large amount of heat. When the temperature of the phase change energy storage chamber (3-12) is higher than that of the fuel chamber (3-11), the fuel in the fuel chamber (3-11) will absorb the heat energy from the phase change energy storage chamber (3-12) and use the fuel chamber (3-11) as an additional heat source. The subcooled liquid leaves the condensation section (8) and enters the condensation line (5-1). After passing through the condensation line (5-1), it enters the compensation chamber (7), mixes with the residual working liquid in the compensation chamber (7), and returns to the evaporation section (6) to complete one cycle. When the wing surface temperature is lower than the temperature of the phase change material in the auxiliary fuel tank, the loop heat pipe system transfers heat to the wing surface: At this time, the solid-liquid phase change material CaCl2·6H2O / EG in the phase change energy storage cavity (3-12) is in the heat pipe condensation section (8) of the heating circuit. At this time, CaCl2·6H2O / EG rapidly releases heat and crystallizes rapidly, releasing latent heat and solidifying at 29.01℃. At this time, the phase change releases a large amount of heat. When the temperature of the phase change energy storage cavity (3-12) is lower than that of the fuel cavity (3-11), the fuel in the fuel cavity (3-11) transfers the stored heat to the phase change energy storage cavity (3-12) to further provide heat for de-icing. The working fluid absorbs heat to form steam, which enters the evaporation section (6) through the evaporation pipeline (5-2). The steam releases heat in the evaporation section (6) to heat the wing surface skin and then condenses to form a subcooled fluid. Driven by the capillary force of the heat pipe core, the fluid leaves the evaporation section (6) and enters the compensation chamber (7). After mixing with the residual fluid in the compensation chamber (7), it returns to the condensation section (8) through the condensation pipeline (5-1) to complete one cycle.

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