A distributed power fixed-point take-off and landing portable solar-powered drone

Abstract

The present invention relates to a portable solar-powered drone capable of fixed-point takeoff and landing, and belongs to the technical field of overall integrated drone design. The drone comprises a front wing and a rear wing arranged in a tandem wing configuration, and a folding assembly connected therebetween. The leading edges of the front and rear wings are each provided with a plurality of rotors along the span direction. The four rotors located between the front and rear wings in the span direction are located at the four vertices of a quadrilateral, forming the drone's four-rotor power system. The remaining rotors form the drone's fixed-wing power system. The folding assembly connects the front and rear wings into a tandem wing with a spatial height difference, and can be deformed to stack the front and rear wings. The present invention solves the problems of a tail-seat aircraft having a single type of propeller that consumes a lot of energy, has low efficiency during the cruise phase, and results in a short flight time.

Description

Technical Field

[0001] The present invention belongs to the technical field of overall integrated design of unmanned aerial vehicles (UAVs), and in particular relates to a portable solar-powered UAV with fixed take-off and landing function. Background Art

[0002] The vast, sparsely populated Qinghai-Tibet Plateau, with its thin air and low pressure and lack of oxygen, limits the range and efficiency of wildlife rangers. Drone technology offers a potential way to alleviate their workload. While existing quadcopter drones are relatively mature, their flight time and range are limited, making them inadequate for wildlife rangers and scientific expeditions. Therefore, fixed-wing solar-powered drones are needed.

[0003] Currently, solar-powered drones used for plateau ecological monitoring mostly adopt high-aspect-ratio designs. These are large, difficult to carry, and require assembly, making them unsuitable for single-person use. Furthermore, most existing solar-powered drones utilize a rolling takeoff and landing system, making it difficult to find suitable landing sites in the wild. Given these limitations, there is a need for a portable solar-powered drone capable of fixed-point takeoff and landing.

[0004] Based on their overall configuration and power type, the current mainstream fixed-wing takeoff and landing UAVs can be divided into three types: lift-thrust hybrid, tilt-rotor, and tail-seat. The rotors of lift-thrust hybrids, which provide vertical lift, become ineffective during the cruising phase after takeoff, becoming a burden on the aircraft and failing to meet portability requirements. The tilt-rotor mechanism of tilt-rotor UAVs accounts for a significant portion of the weight, increasing the overall weight of the aircraft. Tail-seat UAVs are compact, lightweight, and maneuverable. Tail-seat solar-powered UAVs disclosed in the prior art utilize a high-aspect-ratio flying wing layout, switching operating modes via ailerons and counter-rotating pitch propellers with automatic tilters. However, these UAVs suffer from low efficiency and short flight time during cruising due to their single propeller type. Furthermore, their high-aspect-ratio design does not address the poor portability and susceptibility to gusts of wind common to existing solar-powered UAVs. Distributed power systems and tandem-wing configurations offer solutions to these problems.

[0005] The problems existing in existing solar-powered drones for plateau ecological monitoring are as follows:

[0006] (1) The existing solar-powered drones for plateau ecological monitoring are large in size, need to be disassembled and assembled, have poor portability, and cannot meet the requirements of single-person use.

[0007] (2) Most of the existing solar-powered drones for plateau ecological monitoring take off and land on a taxiing basis, and are highly dependent on the site and auxiliary equipment.

[0008] (3) The existing solar-powered drones for plateau ecological monitoring that can take off and land at a fixed point have inherent disadvantages due to their lift-thrust composite, tilt-rotation powered, and tail-seat configurations.

[0009] (4) Most of the existing solar-powered drones for plateau ecological monitoring that can take off and land at a fixed point adopt vertical take-off and landing. The vertical take-off method can only provide the drone with vertical acceleration, resulting in a certain amount of energy waste. Summary of the Invention

[0010] Technical issues to be solved:

[0011] In order to avoid the shortcomings of the prior art, the present invention provides a distributed power fixed-point take-off and landing portable solar-powered UAV, which adopts a tandem wing layout. The front and rear wings can be stacked by folding components. The multi-rotor layout design constitutes a distributed power system combining a fixed-wing mode and a four-rotor mode, solving the problems of a tail-seat configuration aircraft with a single type of propeller consuming a lot of energy, having low efficiency during the cruising phase, and resulting in a short flight time. Moreover, the tandem wing layout distributes the center of gravity between the front and rear wings, which helps to maintain the balance of the UAV when affected by gusts during the take-off and landing phases, thereby improving the problem that the tail-seat configuration aircraft is greatly affected by gusts.

[0012] The technical solution of the present invention is: a distributed power fixed-point take-off and landing portable solar-powered drone, comprising a front wing and a rear wing arranged in a tandem wing form and a folding assembly connected therebetween, wherein the leading edges of the front wing and the rear wing are each provided with a plurality of rotors along the span direction, and the four rotors located in the middle of the front wing and the rear wing in the span direction are respectively located at the four vertices of a quadrilateral, constituting the drone's four-rotor power system, and the remaining rotors constitute the drone's fixed-wing power system; the folding assembly connects the front wing and the rear wing into a tandem wing with a spatial height difference, and can make the front wing and the rear wing stacked by deformation.

[0013] A further technical solution of the present invention is: the spatial height difference between the front wing and the rear wing is 0.32 meters to 0.38 meters; the aspect ratio of the front wing is 3.9-4.2; and the aspect ratio of the rear wing is 3.8-4.0.

[0014] A further technical solution of the present invention is: the front wing and rear wing serve as the main lifting surfaces, and their upper surfaces are evenly covered with solar panels. Four rotors are arranged on the leading edge along the span direction, and the eight rotors are respectively located at the vertices of the inner and outer quadrilaterals. The four rotors located in the inner ring are symmetrically installed on the leading edges of the middle parts of the front and rear wings of the UAV along the middle symmetrical plane of the UAV, and are used to provide lift during the take-off and landing stages, and control the flight attitude of the UAV through power differential. The four rotors located in the outer ring are symmetrically installed on the leading edges of the wingtips of the front and rear wings of the UAV along the middle symmetrical plane of the UAV, and are used to provide thrust during the fixed-wing cruise stage, and resist wind through power differential during the take-off and landing stages.

[0015] A further technical solution of the present invention is: when the UAV is in a vertical landing state, the four rotors of the inner ring form a square in a top view, and the center of gravity of the UAV is located at the center of the square.

[0016] A further technical solution of the present invention is: vertical tails are respectively installed at both ends of the rear wing, and the two vertical tails are symmetrically distributed along the middle symmetry plane of the UAV; and elevator ailerons are symmetrically hinged at the trailing edges of both ends of the rear wing.

[0017] A further technical solution of the present invention is: the folding component includes two front and rear wing connecting rods symmetrically distributed on the middle symmetry plane of the drone, one end of the front and rear wing connecting rods is connected to the front wing, and the other end is connected to the rear wing. Two centrally symmetrically installed aluminum alloy transverse folding parts are arranged in the middle section, so that the two ends of the front and rear wing connecting rods can be folded in reverse, and the front and rear wing connecting rods are Z-shaped after folding.

[0018] A further technical solution of the present invention is: a transverse connecting rod is vertically installed between the two front and rear wing connecting rods, the center of gravity of the UAV is located in the middle of the transverse connecting rod, and a battery compartment is installed at its center position, and a battery is installed in the battery compartment to provide energy for the UAV's flight.

[0019] A further technical solution of the present invention is: the rotor includes a motor and a propeller installed at the output end thereof, and the speed of the motor is controlled by an electronic speed regulator to drive the propeller to rotate.

[0020] A further technical solution of the present invention is: the UAV also includes a navigation system, a flight control system, a measurement and control system, airborne cables and a payload compartment; the payload compartment is located in the middle of the leading edge of the front wing, and the navigation system, flight control system, and measurement and control system are installed therein, and the airborne cables are distributed inside the front and rear wings and on the surface of each connecting rod.

[0021] A takeoff support frame for a distributed-power fixed-point takeoff and landing portable solar-powered drone comprises a front tiltable support member and a rear fixed support member, which sets the drone's takeoff angle at 45°. The tiltable support member is used to support the drone's front wing, and tilts forward at the moment of takeoff. The rear fixed support member is used to support the drone's rear wing.

[0022] Beneficial effects

[0023] The beneficial effects of the present invention are:

[0024] (1) The present invention can achieve fixed-point takeoff and landing and fixed-wing cruise. Most existing solar-powered drones take off and land by taxiing, and cannot achieve vertical takeoff and landing or hovering in the air. They are restricted by the environment when in use. The present invention adopts a distributed power system, which divides the power device of the entire aircraft into an inner ring mainly responsible for fixed-point takeoff and landing, and an outer ring mainly responsible for fixed-wing cruise. It realizes large-angle fixed-point takeoff and four-rotor mode landing of fixed-wing aircraft, greatly reducing the requirements for the take-off and landing environment. Compared with four-rotor drones that can take off and land vertically, the present invention increases the flight time and range of the drone.

[0025] (2) The present invention has good portability and can meet the requirements of single-person control and use. The tandem wing layout is adopted to ensure sufficient wing area for laying solar panels while reducing the aspect ratio of the wing; the connecting rod connecting the front and rear wings of the drone is designed to be foldable, and the folding function is achieved by the aluminum alloy transverse folding parts installed on the connecting rod, ensuring the integration of the drone structure while further reducing the size of the drone. The combination of the tandem wing layout and the foldable method greatly reduces the size of the drone, and its folded size can meet the requirements of single-person carrying; at the same time, the present invention adopts a folding integrated design, which does not require disassembly and assembly, is easy to use, and has a low cost of use.

[0026] (3) The present invention has high propulsion efficiency and no thrust redundancy. By adopting a distributed power system with two inner and outer rings, the main power unit of the UAV in each flight phase is within its range of high working efficiency, thereby improving propulsion efficiency; the secondary power unit of the UAV in each flight phase increases the control amount through differential control and plays a role in wind resistance, etc., and each power unit is fully utilized. At the same time, the additional weight increase brought by the lift-thrust compound type and the tilt-rotation power type is avoided, and the center of gravity is distributed between the front and rear wings through the tandem wing layout, which helps to maintain the balance of the UAV when affected by gusts during take-off and landing, and improves the problem that the tail-seat configuration aircraft is greatly affected by gusts.

[0027] (4) The present invention adopts a quadcopter-mode UAV autonomous visually guided landing method, which improves landing accuracy. After the landing command is issued, the UAV switches from fixed-wing cruise mode to quadcopter mode, ensuring stability during vertical landing. Combined with the UAV's autonomous visual guidance method, it achieves precise landing at the target point.

[0028] (5) The present invention adopts a large-angle fixed-point takeoff method, which provides lift for the UAV while also providing a certain horizontal thrust, so that the effective lift provided by the wing can meet the flight requirements as early as possible and reduce energy consumption during the takeoff phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is an overall schematic diagram of the present invention in a level flight state;

[0030] Figure 2 This is a front view of the present invention in level flight;

[0031] Figure 3 It is a top view of the present invention in a level flight state;

[0032] Figure 4 It is a side view of the present invention in level flight state;

[0033] Figure 5 This is an overall schematic diagram of the present invention in a folded state;

[0034] Figure 6 This is a front view of the present invention in a folded state;

[0035] Figure 7 A top view of the present invention in a folded state;

[0036] Figure 8 A side view of the present invention in a folded state;

[0037] Figure 9 Schematic diagram of the overall support state before large-angle fixed-point takeoff of the present invention;

[0038] Figure 10 A side view of the overall support state of the present invention before high-angle fixed-point takeoff;

[0039] Explanation of the accompanying symbols: 1. Front wing; 2. Rear wing; 3. Connecting rod between front and rear wings; 4. Aluminum alloy transverse folding part; 5. Vertical tail; 6. Elevator; 7. Battery compartment; 8. Payload compartment; 9. Battery; 10. Solar panel; 11. Inner ring propeller and motor; 12. Outer ring propeller and motor; 13. Connecting rod junction box; 14. Vertical tail connector; 15. Electronic speed governor; 16. Airborne avionics equipment; 17. Transverse connecting rod; 18. Connector; 19. Support carbon tube; 20. Front upper support; 21. Front middle three-way piece; 22. Front lower support; 23. Rear lower support; 24. Vertical tail support. DETAILED DESCRIPTION

[0040] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0042] Based on the problems that the single type of propeller of the existing tail-seat configuration aircraft consumes a lot of energy and has low efficiency in the cruising stage, resulting in a short flight time; the existing plateau ecological monitoring solar-powered drones are large in size, need to be disassembled and assembled, have poor portability, and cannot meet the requirements of single-person use. The present invention provides a distributed power fixed-point take-off and landing portable solar-powered drone, comprising a front wing and a rear wing arranged in the form of a tandem wing and a folding assembly connected therebetween, wherein the leading edges of the front wing and the rear wing are each provided with a plurality of rotors along the span direction, and the four rotors located in the middle of the front wing and the rear wing in the span direction are respectively located at the four vertices of a quadrilateral, constituting the four-rotor power system of the drone, and the remaining rotors constitute the fixed-wing power system of the drone; the folding assembly connects the front wing and the rear wing into a tandem wing with a spatial height difference, and the front wing and the rear wing can be stacked by deformation.

[0043] Specifically, the height difference between the front wing and the rear wing is 0.32-0.38 meters. The aspect ratio of the front wing is 3.9-4.2; the aspect ratio of the rear wing is 3.8-4.0.

[0044] Specifically, the front wing and rear wing serve as the main lifting surfaces, and solar panels are evenly laid on their upper surfaces. Four rotors are arranged along the span direction of each leading edge, and the eight rotors are respectively located at the vertices of the inner and outer quadrilaterals. The four rotors located in the inner ring are symmetrically installed on the leading edges of the middle front and rear wings of the UAV along the middle symmetrical plane of the UAV, and are used to provide lift during the take-off and landing stages, and control the flight attitude of the UAV through power differential. The four rotors located in the outer ring are symmetrically installed on the leading edges of the front and rear wing tips of the UAV along the middle symmetrical plane of the UAV, and are used to provide thrust during the fixed-wing cruise stage, and resist wind through power differential during the take-off and landing stages.

[0045] Specifically, when the UAV is in a vertical landing state, the four rotors of the inner ring form a square in a top view, and the center of gravity of the UAV is located at the center of the square.

[0046] Specifically, vertical tails are installed at both ends of the rear wing, and the two vertical tails are symmetrically distributed along the middle symmetry plane of the UAV; and elevator ailerons are symmetrically hinged at the trailing edges of both ends of the rear wing.

[0047] Specifically, the folding assembly includes two front and rear wing connecting rods symmetrically distributed on the middle symmetry plane of the drone, one end of the front and rear wing connecting rods is connected to the front wing, and the other end is connected to the rear wing. Two centrally symmetrically installed aluminum alloy transverse folding parts are set in the middle section, so that the two ends of the front and rear wing connecting rods can be folded in opposite directions. After folding, the front and rear wing connecting rods are in a Z shape.

[0048] Specifically, a transverse connecting rod is vertically installed between the two front and rear wing connecting rods. The center of gravity of the drone is located in the middle of the transverse connecting rod, and a battery compartment is installed at its center. The battery compartment is equipped with batteries to provide energy for the drone's flight.

[0049] Specifically, the rotor includes a motor and a propeller installed at the output end thereof. The speed of the motor is controlled by an electronic speed regulator, thereby driving the propeller to rotate.

[0050] Specifically, the UAV also includes a navigation system, a flight control system, a measurement and control system, airborne cables and a payload compartment; the payload compartment is located in the middle of the leading edge of the front wing, and the navigation system, flight control system, and measurement and control system are installed in it. The airborne cables are distributed inside the front and rear wings and on the surface of each connecting rod.

[0051] The above technical solution is further described below with reference to the accompanying drawings:

[0052] Reference Figure 1-Figure 4 As shown, this embodiment is a distributed power fixed-point take-off and landing portable solar-powered UAV, which includes three parts: an airframe structure, an energy power system, and an onboard avionics system.

[0053] The aircraft structure includes a front wing 1, a rear wing 2, a connecting rod 3 for the front and rear wings, an aluminum alloy transverse folding member 4, a vertical tail 5, an elevon 6, a battery compartment 7, a payload compartment 8, a connecting rod junction box 13, a vertical tail connector 14, a transverse connecting rod 17, and a connector 18. The front wing 1 and rear wing 2 are both the primary lifting surfaces of the drone, forming a tandem wing layout. To ensure portability, both are designed as low-aspect-ratio straight wings. The front wing 1 has a span of 1.2 meters and a chord length of 0.3 meters, while the rear wing 2 has a span of 1.2 meters and a chord length of 0.31 meters. These airfoils have high lift coefficients to meet the needs of cruise conditions and increase the drone's range and flight time. The vertical tail 5, serving as the drone's vertical stabilizer, is mounted at the end of the rear wing 2 and connected to the rear wing 2 via a vertical tail connector 14. The front wing 1 and rear wing 2 are connected by a front and rear wing connecting rod 3. Connectors 18 are installed at the intersection of the front and rear wing connecting rods 3 and the wing spar, achieving multi-point connection between the front and rear wing connecting rods 3 and the wings, thereby improving the structural strength and rigidity. Two transverse connecting rods 17 are installed between the two front and rear wing connecting rods 3, with their installation positions coordinated with the design center of gravity of the entire drone. A battery compartment 7 is installed in the middle of the transverse connecting rods 17 to accommodate the batteries 9 required by the drone. The transverse connecting rods 17 are fixedly connected to the front and rear wing connecting rods 3 via a connecting rod junction box 13, forming an "H"-shaped layout for the connecting rods, thereby improving the drone's torsional resistance. A payload compartment 8 is installed in the middle of the leading edge of the front wing 1 to accommodate the onboard avionics equipment 16. An integrated design integrates the payload compartment 8 with the structure of the front wing 1 to reduce the size and weight of the drone. The control surface of the drone of the present invention includes two elevons 6 symmetrically hinged to the outer sides of the trailing edge of the rear wing 2, which, together with the power differential method, realize the flight control of the drone.

[0054] Reference Figure 5-Figure 8 As shown, four aluminum alloy transverse folding members 4 are symmetrically mounted on the two front and rear wing connecting rods 3. The two folding members on the front wing are installed opposite the two folding members on the rear wing, achieving reverse folding. When the aluminum alloy transverse folding members 4 reach the folding limit, the length and height of the drone are reduced, reducing the drone's size and improving its portability.

[0055] The energy and power system includes: batteries 9, solar panels 10, inner propellers and motors 11 (rotors), outer propellers and motors 12, and an electronic speed controller 15. Battery 9, a high-energy-density lithium-ion battery, is installed in battery compartment 7 and provides energy for the drone. Solar panels 10, flexible thin-film solar cells with high photoelectric conversion efficiency, are evenly distributed on the upper surfaces of front wings 1 and rear wings 2, providing energy for the drone's flight and extending its range. There are four inner ring propellers and motors 11, which are symmetrically installed on the middle leading edges of the front wing 1 and the rear wing 2 along the middle symmetrical plane of the UAV. They are mainly used to provide lift during take-off and landing, and to control the flight attitude of the UAV through power differential. Therefore, the inner ring propeller adopts a large-size low-pitch propeller, and the inner ring motor adopts a low-kv value brushless DC motor that matches the inner ring propeller to drive the rotation of the propeller; the inner ring motor is installed on a motor base that is integrated with the wing structure. In order to meet the requirements of the four-rotor mode, the installation position of the inner ring propeller and the motor 11 needs to make the inner ring propeller form a square in the top view in the vertical landing state, and the design center of gravity of the UAV needs to be in the middle of the square. There are four outer ring propellers and motors 12, which are symmetrically installed on the leading edges of the wingtips of the front wing 1 and the rear wing 2 along the middle symmetrical plane of the drone. They are mainly used to provide thrust during the fixed-wing cruise phase and to resist wind through power differential during the take-off and landing phases. Therefore, the outer ring propeller adopts a large-pitch propeller with higher efficiency at a high advance ratio, and the outer ring motor adopts a low-kv value brushless DC motor that matches the outer ring propeller. Similarly, the outer ring motor is also installed on a motor base that is integrated with the wing structure. The installation of the inner ring propeller and motor 11 and the outer ring propeller and motor 12 needs to consider their distance from the front and rear wing connecting rods 3 and the payload compartment 8, and a certain safety distance needs to be left. The electronic speed regulator 15 is fixed to the bottom of the battery compartment 7 and is used to control the speed of the motor.

[0056] The onboard avionics system includes onboard avionics equipment 16 and onboard cables (not shown). The onboard avionics equipment 16 is distributed and installed in the payload bay 8, and includes a navigation system, a flight control system, and a measurement and control system. The onboard cables are distributed inside the front wing 1 and rear wing 2, as well as on the surfaces of the front and rear wing connecting rods 3 and the transverse connecting rods 17. Cable ties and tape are used to secure the exposed portions of the onboard cables to the aircraft body. It is necessary to reduce the number of onboard cables through reasonable arrangement, and to select lighter cables to reduce the total weight of the UAV.

[0057] Reference Figure 9-10 As shown, the large-angle fixed-point takeoff bracket for the UAV of this embodiment is used for overall support of the UAV before takeoff, and includes a front tiltable support member and a rear fixed support member.

[0058] The front tiltable support member includes: a supporting carbon tube 19, a front upper support member 20, a front middle three-way member 21, and a front lower support member 22. There are three supporting carbon tubes 19 in total, which connect the front upper support member 20, the front middle three-way member 21, and the front lower support member 22 into one body. They are detachable, which reduces the consumables of the support member while increasing the portability of the support member. The length of the supporting carbon tube 19 is determined according to the take-off angle of the drone. The upper part of the front upper support member 20 is an arc less than 180°, which is supported under the middle part of the front beam of the front wing 1. The lower part is a sleeve, which is connected to the supporting carbon tube 19. The front upper support member 20 needs to be able to provide support for the drone before take-off and to detach from the drone in time after being disturbed by the drone's take-off. The front middle three-way member 21 is a sleeve assembly with a certain angle between each other, connecting the supporting carbon tubes 19 in three directions. The front lower support member 22 is two sleeve members with a base, which are respectively connected to the two oblique supporting carbon tubes 19. The base can increase the contact area between the front tiltable support member and the ground, and increase the stability of the support in the static state. However, the base cannot be too large. It is necessary to ensure that the front tiltable support member can tilt forward after being disturbed by the drone takeoff to avoid collision with other parts of the drone and ensure the stability of the drone takeoff.

[0059] The rear fixed supports consist of two sets of rear lower supports 23 and vertical tail supports 24, placed below the two vertical tails of the drone. The upper portions of the vertical tail supports 24 are recessed to accommodate the tails, tailing the shape of the drone's vertical fins. These grooves limit lateral displacement during the initial takeoff phase, maintaining the drone's intended takeoff angle and ensuring safe takeoff. The rear lower supports 23 provide three-dimensional support for the vertical tail supports 24 and are integrally designed with them. The rear fixed supports are non-tipable and provide fixed support.

[0060] Working status:

[0061] The flight process of the distributed power fixed-point takeoff and landing portable solar-powered drone of the present invention includes: a large-angle fixed-point takeoff phase, a takeoff transition phase, a fixed-wing cruise phase, a landing glide phase, a landing transition phase, and a fixed-point vertical landing phase. The following describes each flight phase of the drone of this embodiment to illustrate its specific working method:

[0062] During the high-angle fixed-point takeoff phase, the drone lifts off from the takeoff point at a high angle. A sufficiently large throttle command is applied at the moment of liftoff to ensure that the vertical component of the force overcomes gravity. The drone accelerates off the ground under the pull of the propellers, using the upper and lower wings' differential power to control pitch, while the left and right wings' differential power to control roll and yaw. Once the drone reaches a certain speed, the elevons' steering effect is sufficient to control the drone's attitude, and the elevons begin to operate, controlling pitch and roll. The left and right differential power coordinates to eliminate sideslip.

[0063] After the UAV climbs to the specified altitude according to the given climb trajectory, it enters the takeoff transition phase. The UAV gradually lowers its head, reduces the pitch angle and increases the speed. During this period, the thrust distribution strategy is switched to distribute the desired thrust of the UAV to the outer ring propeller until the UAV reaches the cruising level flight speed and enters the fixed-wing cruise phase when the track angle is reduced to 0°.

[0064] During the fixed-wing cruise phase, the drone performs scheduled tasks such as ecological monitoring.

[0065] During the landing descent phase, the drone receives the landing command and uses a recognition and positioning algorithm to determine the landing point coordinates. It then adjusts its flight attitude to track the descent path. The elevons control pitch and roll angles, while the left and right power differentials coordinate to eliminate sideslip.

[0066] During the landing transition phase, the drone descends to a designated altitude and rapidly begins to pull up. The drone's pitch angle is increased by controlling the elevons and the differential rotation of the front and rear propellers. During this phase, the thrust distribution strategy is switched, distributing the desired thrust to the inner propellers until the drone reaches a vertical position, where the inner propeller thrust completely balances gravity. During this period, any lateral disturbances to the drone are balanced by the elevons and outer propellers. Once vertical, the drone switches to quadrotor mode for landing.

[0067] During the fixed-point vertical landing phase, the drone uses quadrotor mode for a fixed vertical landing. The inner propellers balance gravity, while the outer propellers generate the torque needed to control the drone's attitude. The drone follows a landing trajectory to the landing point. When the drone is 1-2 meters off the ground, it lowers its head and slowly lands on the ground, completing the fixed-point vertical landing.

[0068] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A distributed power fixed take-off and landing portable solar-powered drone, characterized by: The invention comprises a front wing and a rear wing arranged in the form of a tandem wing and a folding assembly connected therebetween. The leading edges of the front wing and the rear wing are each provided with a plurality of rotors along the span direction. The four rotors located in the middle of the front wing and the rear wing in the span direction are respectively located at the four vertices of a quadrilateral, forming a four-rotor power system of the UAV, and the remaining rotors form a fixed-wing power system of the UAV. The folding assembly connects the front wing and the rear wing into a tandem wing with a spatial height difference, and the front wing and the rear wing can be stacked by deformation.

2. The distributed power fixed-point take-off and landing portable solar-powered drone according to claim 1, characterized in that: The spatial height difference between the front wing and the rear wing is 0.32 meters to 0.38 meters; the aspect ratio of the front wing is 3.9-4.2; and the aspect ratio of the rear wing is 3.8-4.

0.

3. The distributed power fixed take-off and landing portable solar-powered drone according to claim 1, characterized in that: The front and rear wings serve as the main lifting surfaces, and solar panels are evenly laid on their upper surfaces. Four rotors are set along the span of their leading edges, and the eight rotors are respectively located at the vertices of the inner and outer quadrilaterals. The four rotors located in the inner ring are symmetrically installed on the leading edges of the middle parts of the front and rear wings of the UAV along the middle symmetrical plane of the UAV, and are used to provide lift during the take-off and landing stages, and control the flight attitude of the UAV through power differential. The four rotors located in the outer ring are symmetrically installed on the leading edges of the wingtips of the front and rear wings of the UAV along the middle symmetrical plane of the UAV, and are used to provide thrust during the fixed-wing cruise stage, and resist wind through power differential during the take-off and landing stages.

4. The distributed power fixed take-off and landing portable solar-powered drone according to claim 3, characterized in that: When the UAV is in a vertical landing state, the four rotors of the inner ring form a square in a top view, and the center of gravity of the UAV is located at the center of the square.

5. The distributed power fixed-point take-off and landing portable solar-powered UAV according to claim 1, characterized in that: The ends of the two ends of the rear wing are respectively equipped with vertical tails, and the two vertical tails are symmetrically distributed along the middle symmetry plane of the UAV; the trailing edges of the two ends of the rear wing are symmetrically hinged with elevator ailerons.

6. The distributed power fixed-point take-off and landing portable solar-powered UAV according to claim 1, characterized in that: The folding assembly includes two front and rear wing connecting rods symmetrically distributed on the middle symmetry plane of the drone, one end of the front and rear wing connecting rods is connected to the front wing, and the other end is connected to the rear wing. Two centrally symmetrically installed aluminum alloy transverse folding parts are provided in the middle section, so that the two ends of the front and rear wing connecting rods can be folded in opposite directions. After folding, the front and rear wing connecting rods are in a Z shape.

7. The distributed power fixed take-off and landing portable solar-powered UAV according to claim 6, characterized in that: A transverse connecting rod is vertically installed between the two front and rear wing connecting rods. The center of gravity of the drone is located in the middle of the transverse connecting rod, and a battery compartment is installed at its center. The battery compartment is equipped with batteries to provide energy for the drone's flight.

8. The distributed power fixed-point take-off and landing portable solar-powered UAV according to claim 1, characterized in that: The rotor includes a motor and a propeller installed at the output end thereof. The speed of the motor is controlled by an electronic speed regulator, thereby driving the propeller to rotate.

9. The distributed power fixed-point take-off and landing portable solar-powered UAV according to claim 1, characterized in that: The UAV also includes a navigation system, a flight control system, a measurement and control system, airborne cables and a payload compartment; The load compartment is located in the middle of the leading edge of the front wing, and is equipped with a navigation system, a flight control system, and a measurement and control system. The onboard cables are distributed inside the front and rear wings and on the surfaces of each connecting rod.

10. A takeoff support frame for a portable solar-powered UAV capable of taking off and landing at a distributed power point according to any one of claims 1 to 9, characterized in that: It includes a front tiltable support and a rear fixed support, which determine the take-off angle of the drone to 45°; the tiltable support is used to support the front wing of the drone, and the tiltable support tilts forward at the moment of take-off; the rear fixed support is used to support the rear wing of the drone.

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