Air cargo transport device

Abstract

[Problem] Drones have limited lift capacity, and while suitable for vertical movement as standalone units, drones have a short flight range and are not suitable for the aerial transport of substantial cargo via horizontal flight. [Solution] An air cargo transport device characterized by comprising: a transport container on which cargo is mounted and which is provided with a flying wing having a variable dihedral angle; a driving flight body that tows the container; and a plurality of connection bodies that connect the container and the driving flight body, wherein one end of each connection body is attached to the driving flight body and the other end of each connection body is attached to the container, the container is suspended from the driving flight body and achieves lift off thereby, the transport container flies via the lift of the flying wing during towing parallel flight, the dihedral angle of the flying wing during towing is set in accordance with the weight of the cargo, and the plurality of connection bodies are operated in accordance with the behavior of the driving flight body.

Description

Air cargo transport equipment

[0001] This invention relates to an air cargo transport system using flying vehicles such as drones.

[0002] In recent years, multi-rotor drones have been used for aerial photography and image capture. While multi-rotor drones excel at rapid vertical takeoff and landing and short-distance flight, efforts are currently being made to increase their use in cargo transport, particularly for short-distance, short-duration deliveries.

[0003] In light of this situation, the inventors first considered the following points. Multi-rotor drones are not suitable for air transport over longer distances, such as 5 to 10 km or more, or for air transport of heavy cargo. The drawback of multi-rotor drones is that the lift generated by the multiple small-diameter propellers is smaller compared to that of large-diameter propellers. As propellers are a type of wing, also known as rotor blades, they generate lift by cutting through the wind. As shown in Figure 22(d), the faster the rotor blade R cuts through the wind S, the greater the lift P it generates. However, the lift of a single rotating blade varies greatly depending on the part of the blade. That is, the circumference of the inner part of the blade, closer to the axis of rotation, is small, the rotation distance of the blade is short, the wind cutting speed S is low, and proportionally the lift P is small. The outer edge of the same blade has the largest circumference, the longest rotation distance, and generates the greatest lift. While a single large-diameter propeller, like those found on so-called helicopters, maximizes the lift generated primarily by its outer portion, a drone using four or more small-diameter propellers of the same overall diameter will generate less lift than a single large-diameter propeller, even with multiple propellers.

[0004] From this point of view as well, multi-rotor drones, which are attracting attention for their ease of handling, are not suitable for cargo transportation. That is, the rotor blades of a multi-rotor drone are extremely short compared to the single rotor blade of a helicopter-type helicopter. Even when four or more rotor blades are used, they generally have no advantage in lift over a single rotor blade of a single-rotor aircraft and are inferior in this respect. Nevertheless, multi-rotor drones have drawn attention only for their characteristic of being unaffected by reverse torque and having excellent vertical ascent and descent capabilities, due to the presence of their multiple rotors arranged in a counter-torque layout. Their utilization that leverages this feature is mainly for applications requiring rapid takeoff and landing and short-distance aerial movement.

[0005] Multi-rotor drones, which are not advantageous in terms of lift, are not suitable for carrying cargo over long distances that require large lift for a long time, and additionally have the following inconveniences when performing flight with cargo loaded. That is, as shown in Fig. 22(a), when loading a container 10 containing cargo onto a multi-rotor drone body 1, the cargo container 10 is usually mounted to the lower part of the drone body 1. As shown in Fig. 22(b), during horizontal movement, the headwind received from the forward direction D causes air resistance W acting on the container 10, which tends to make the flight attitude of the drone body 1 pitch forward. As shown in Fig. 22(c), the attitude tilt (forward pitch) of the body reduces the projected area of the rotor blades R from X to Y. This reduction causes a problem that even the original lift performance of the drone is decreased. The larger the front area of the loaded container 10, the greater the degree of forward pitch, and this disadvantage of reduced lift becomes more pronounced. As described above, the increase in weight and the forward pitching require a significant increase in the rotational speed of the rotors to obtain the required lift. This greatly increases power consumption in multi-rotor drones that normally fly using power from a limited capacity storage battery, making them increasingly disadvantageous for long-distance transportation.

[0006] Furthermore, Patent Document 1 discloses developing a multicopter with a long cruising range by providing a multi-rotor aircraft with a power generation function. In this multicopter, a plurality of rotor blades rotated by a motor to generate lift are attached to a body section, but this requires the mounting of a complicated and heavy power generation mechanism.

[0007] Japanese Patent Publication No. 6856911 Furthermore, according to the inventors' studies, so-called cargo transport aircraft equipped with a horizontal drive mechanism and horizontal fixed wings are more efficient in horizontal movement and are therefore considered more efficient than cargo transport by multi-rotor drones. However, cargo transport aircraft equipped with a horizontal drive mechanism and horizontal fixed wings are robust, heavy, and expensive aircraft, and have fundamental problems that make them unsuitable for simple transport, such as requiring a certain amount of land area for a runway and dedicated maintenance at each takeoff and landing site.

[0008] Based on the above analysis and considerations, this invention provides an air cargo transport device that does not rely on the lift generated by the drone itself for horizontal flight transport, but instead uses a simple aircraft capable of securing lift to handle the horizontal movement of cargo, thereby realizing a horizontal flight mechanism in which the drone and the aircraft are integrated. This enables long-duration, long-distance air transport of cargo using existing drones without the need for large runways.

[0009] The present invention provides an air cargo transport system comprising a transport container equipped with a cargo-loading, dihedral-angled flight wing, a towing aircraft for towing the container, and a connecting body for connecting the container and the towing aircraft, wherein one end of the connecting body is attached to the towing aircraft and the other end is attached to the container, the towing aircraft lifts the container and allows it to take off, the transport container and the towing aircraft are propelled by the lift generated by the flight wing during towing, the dihedral angle of the flight wing during towing is set according to the weight of the cargo, and the connecting body operates according to the behavior of the towing aircraft.

[0010] Furthermore, the present invention relates to an air cargo transport device in which the drive aircraft is a multi-rotor drone, the transport container is suspended and taken off by the multi-rotor drone when the container lands, the transport container is positioned at a point that receives an updraft when the container takes off, the connecting body is a pair of left and right distance bars attached to the multi-rotor drone, and the pair of distance bars are moved independently in accordance with the behavior of the drone, and the distance bars are The present invention provides a configuration having an S-shape with semicircular sections of different diameters, a configuration in which a base bar is connected to a pair of distance bars, and the connection portion between the distance bars and the base bar is provided with an up-down, left-right movable connection portion of the distance bars, a configuration in which the up-down, left-right movable connection portion is provided with an opening provided in a part of the distance bar and a wire cable portion passing through the opening, and a part of the distance bar is made movable up-down, left-right, and right, and a configuration in which the flight wing consists of a main wing and a tail wing, and the main wing and tail wing are connected by a body frame of variable length.

[0011] The present invention relates to a transport device in which a drone, which is a drive aircraft that tows a transport container after takeoff and during horizontal flight, and a transport container equipped with variable dihedral-angle flight wings and carrying cargo are integrated into a single flight mechanism. The height of the entire flight mechanism during horizontal flight is maintained by the lift generated by the wings of the container, and the horizontal towing force in this flight mechanism is generated by the drone, making it possible to minimize or almost eliminate the lift burden on the drone's multi-rotor for maintaining height during horizontal flight. The lift generated by the drone can be used only for short periods during takeoff and landing when suspending the container. This means that during long-duration towing parallel flight, the energy consumption of the drone's multi-rotor drive is significantly less than when the drone itself carries the cargo, for example, it can be reduced to about 10%, resulting in significant energy savings and a substantial increase in transport distance. Thus, the air cargo transport device of the present invention can compensate for the disadvantages of multi-rotor drones in terms of lift capacity and flight speed / distance.

[0012] Furthermore, according to the present invention, the transport container is equipped with a flight wing with a variable dihedral angle, and the lift can be varied simultaneously with the change in the projected area of ​​this wing, making it possible to achieve an optimal dihedral angle according to the size and weight of the cargo, and thus enabling the creation of transport containers tailored to the type of cargo.

[0013] Furthermore, since the propulsion system and the transport container are separate components, it becomes possible to create a simple and lightweight transport container without a propulsion system. In addition, when the cargo is light or when the container is empty after transporting cargo, it is possible to increase the dihedral angle of the flight wings and reduce the projected wing area to reduce lift and make it less susceptible to the effects of turbulent airflow.

[0014] Furthermore, the connecting body is composed of a pair of distance bars attached to a multi-rotor drone. By independently moving each of the distance bars in accordance with the drone's movements, when the towing multi-rotor drone, for example, turns left, tilts to the left, and the distance bar on the turning side sinks downward and moves backward simultaneously. This causes the left and right distance bars to shift forward, backward, and up and down. In response to this, the container section tilts towards the turning side, and a force is applied to orient the nose in the direction of the turn. In this way, stable flight of the transport container in accordance with the drone's movements is possible without having to manipulate the flight wings themselves in accordance with the drone's movements.

[0015] Furthermore, by using an S-shaped distance bar (also called a swan neck bar) instead of a straight shape, when the container is positioned above and behind the drone's propulsion system, the distance bar can prevent contact between the container and the drone's propellers, thus avoiding unnecessary interference. In addition, the S-shaped distance bar allows the container to be fixed to the lower center of the drone's body when suspended, enabling stable suspension.

[0016] Furthermore, if the flight wing consists of a main wing and a tail wing that assists in stability, a mechanism that allows for variable clearance between the main wing and tail wing, which is related to optimal stability, can be easily realized by extending and retracting the body frame connecting them.

[0017] In the air cargo transport device of the present invention, when the transport container is positioned at a point where it receives an updraft during takeoff, the lift force during takeoff is increased by the container's flight wings, making it possible to save energy for the drone during takeoff.

[0018] Figures (a) to (e) show the connection, suspension, and horizontal flight conditions of an air cargo transport device according to one embodiment of the present invention. Figures (a) and (b) are schematic external views of the structure and movement of the connecting body (S-shaped distance bar) of the air cargo transport device during straight flight and when the rear side is twisted due to the tilt during turns, and figure (c) is an external view of the base bar of the device. Figure (a) is a schematic front view of the container part of the device, figure (b) is a schematic view of the device when the dihedral angle is at its minimum, and figure (c) is a schematic view of the device when the dihedral angle is at its maximum, and figures (d) and (e) are schematic front views of the container in figures (b) and (c). Figures (a) and (b) are explanatory diagrams of the dihedral angle state of the main wing of the container. is a schematic front view of the container when cargo is loaded on the bottom. Figures (a) and (b) are diagrams explaining the dihedral angle variable mechanism of the main wing using strut pins, and figures (c) and (d) show the external structure of the strut pin part. Figures (a) and (b) show the assembly and operation of the strut pins. This is a schematic diagram of the overall structure of an air cargo transport device according to one embodiment of the present invention. This is an operational diagram illustrating the takeoff flight situation of the air cargo transport device. This is an operational diagram illustrating the takeoff flight situation of the air cargo transport device. This is an operational diagram illustrating the takeoff flight situation of the air cargo transport device. This is an operational diagram illustrating the takeoff flight situation of the air cargo transport device. This is an operational diagram illustrating the takeoff flight situation of the air cargo transport device. This is an operational diagram illustrating the takeoff flight situation of the air cargo transport device. This is an operational diagram illustrating the takeoff flight situation of the air cargo transport device. This is an operational diagram illustrating the takeoff flight situation of the air cargo transport device. This is an operational diagram illustrating the takeoff flight situation of the air cargo transport device. This is an operational diagram illustrating the takeoff flight situation of the air cargo transport device. Figure 19 is an illustrative diagram of energy consumption at various horizontal distances and altitudes during takeoff and landing when a multi-rotor drone is loaded with cargo. (a) is a diagram showing energy consumption at different altitudes during flight, represented by the number of lines, and (b) is a diagram showing the amount of energy consumed during flight. Figure 19 is an illustrative diagram of the energy consumption of the present invention device in the same flight conditions as in Figures 9 and 18, using the same drone as in Figure 19 and the same cargo weight as in Figure 18.Figures 12 to 17 illustrate similar energy consumption during takeoff in high-altitude or updraft-enabled flight conditions. (a) to (d) are explanatory diagrams of conventional cargo transport situations using multi-rotor drones.

[0019] Figure 1(a) shows the area around the container 10 of an air cargo transport device according to one embodiment of the present invention, and Figure 1(b) shows the pre-takeoff state (for example, a waiting state on the ground or on a takeoff platform) with a removable cartridge-type container 10 and a multi-rotor drone body 1 connected. An S-shaped (swan-neck type) distance bar 4, which constitutes a connector, is attached to the frame bar 6 of the container 10. Note that two distance bars 4 are configured as a pair, but only one is shown in this figure for explanatory purposes. The distance bar 4 is connected to the container side at the hook point 5 of the upper frame bar 6 and to the lower part of the drone side at the hook point 3 of the drone side using stud bolts. The main wing (flight wing: dihedral V-shaped wing) 9 is attached to the main wing attachment part 7 of the lower frame bar 7 by a dihedral angle variable mechanism (described later). A tail wing 11 (dihedral V-shaped wing) for flight stabilization is attached to the rearmost part of the rear section 13 of the frame bar, and auxiliary wheels 12 are provided for use during takeoff and landing when using a runway. The wing 9 can be made of lightweight wood and carbon fiber, or a flexible wing consisting of canvas or polyester fabric and a frame.

[0020] The rotor blades R of the drone 1 are driven to suspend the container 10 vertically, as shown in Figure 1(c). In this state, the drone 1 pulls the container 10 diagonally upward {Figure 1(d)} until the height difference between the container 10 and the drone 1 disappears and the container 10 enters a horizontal flight state {Figure 1(e)} (a gliding state). Then, the drone 1 horizontally pulls the container 10 in the Z direction. The lift generated on the main wings 9 of the container 10 during this horizontal flight maintains the height of both the container 10 and the drone 1. The horizontal drive of the drone 1 is solely responsible for the horizontal movement of the drone 1 itself and the container 10. Furthermore, with this flight mechanism, vertical landing is possible during landing, as shown in Figure 18, which will be described later, just as during takeoff. As mentioned above, in this flight mechanism, the height of the flight mechanism, in which the drone 1 and the container 10 are integrated, is maintained during horizontal movement in the air by the lift generated by the main wings 9 during the horizontal towing movement, and the horizontal movement in the air is performed by the horizontal thrust of the drone 1. A small thrust is required for this horizontal movement. In this configuration, the drone 1 does not need to generate the lift required for its own flight, and the energy consumed by the drone 1 for horizontal flight movement when towing the container 10 is significantly less than the energy required to secure lift during the drone's solo flight. This means that horizontal flight using this integrated flight mechanism significantly reduces the energy consumption of the drone 1, which flies using the power of its onboard battery, and enables a significant increase in transport distance. The propeller thrust in the forward direction of the drone is improved by tilting the drone forward. In the device shown in Figure 1, as shown in (e), it is possible to intentionally give the drone a forward tilt angle by lifting the lower part of the drone 1 via the S-shaped distance bar 4 using the lift of the main wing 9 of the container. This increases the propeller thrust in the forward direction. In other words, with the height of the drone 1 secured by the lift of the main wing 9, it becomes possible to use all of the thrust power generated by the drone's propellers as thrust for forward movement. It is also effective to add an additional protruding member to the distance bar 4 to make it easier to lift the lower part of the drone 1.

[0021] This section explains the energy reduction effect of the above flight mechanism in cargo transport compared to cargo transport by a drone alone during horizontal flight. We will consider the static thrust (thrust power) required for horizontal flight based on the calculation formula for a gliding state. Assuming a total cargo weight of 30 kg (10 kg for the drone body + 20 kg for the cargo) in a multi-rotor drone, to generate the static thrust necessary for hovering (maintaining airborne position after takeoff), the propellers must continuously generate 30 kg of lift (the numerical value of the force required to maintain a hovering state after takeoff). The drone will maintain horizontal movement during air transport while constantly consuming the energy required for this. On the other hand, assuming a total weight of 30 kg, the static thrust required to push the flight mechanism shown in Figure 1 horizontally with the flight wings can be calculated by dividing the total weight of 30 kg by the glide ratio of the main wing performance. Assuming a glide ratio of 10:1 (corresponding to a value of 10 used in the calculation of static thrust (thrust power)), the best gliding state of the flight mechanism of the present invention requires only 30 kg / 10 (3 kg) of lift. Although the weight of the container is added to the flight mechanism of the present invention, the container itself can be made lightweight (for example, 1 to 3 kg), and the effect of the container's weight can be kept to a minimum. Thus, during horizontal flight in the air, the energy consumption of the drone using the flight mechanism of the present invention is only about 10% of that of air transport using a cargo-carrying drone.

[0022] As shown in Figure 2, the metal S-shaped distance bars 4 that constitute the connecting body of the air cargo transport device of the present invention are arranged in pairs and connected by cylindrical front base bars 23 and rear base bars 24. Pulleys 26 are mounted in pulley opening free grooves 28 at each of the four ends (connecting parts) of the left and right distance bars 4. Wire cables 25 that communicate with the pulleys 26 are routed inside the front base bars 23 and rear base bars 24, and wire cable stoppers 27 are provided at the ends of the wire cables 25. A portion of the wire cable 25 between the front base bars 23 and rear base bars 24 and the stoppers 27 is positioned (passes through) the free grooves 28, and a portion of the cable 25 can move up, down, left, and right within the grooves 28. This structure and mechanism is provided at the four ends (connecting parts) of the distance bars 4.

[0023] This connecting structure has base bars 23 and 24 connecting the left and right sides at the front and rear of both the drone and the container. A wire cable 25 is passed through the cylindrical base bar and secured at the end with a stopper 27, allowing free movement at the four connection points in total (front, back, left, and right). When the towing multi-rotor drone turns (left turn indicated by arrow T in Figure 2b), it tilts to the left, causing the distance bar 4 on the turning side to sink downward and retract simultaneously, as shown in Figure 2b. This creates a front-to-back displacement and an up-and-down displacement (a twisting state on the rear side) in the left and right distance bars. In conjunction with this, the container section tilts towards the turning side, and a force acts to orient the aircraft in the direction of the turn.

[0024] The S-shaped distance bars 23 and 24 (also called swan neck bars) have a curved space, which prevents the distance bars from contacting or interfering with the propellers when the container is positioned above and behind the drone body, which is the propulsion unit (Figure 1e). Each of the distance bars 23 and 24 has an S-shape with curved ends, and the ends of the connecting base bars 23 and 24 move freely within grooves 28 provided within the bars, in response to the forces generated by the front and rear loads. This structure controls the direct interaction of excessive forces in either the front or rear direction, making it easier to achieve stable flight. In addition, by fixing these S-shaped distance bars to the lower center of the drone body when suspending the container, the container is suspended along the center. In this way, by using S-shaped distance bars that combine semicircles of different diameters, it is possible to respond well to changes in the connection angle between when the container is suspended and when the horizontal angle of attack is at ground level during self-propelled flight. Figure 2(a) shows the condition during straight flight, and Figure 2(b) shows the condition during turning, where the left bar moves backward and downward due to the tilt, resulting in a twist to the left.

[0025] The dihedral angle of the flight wing (V-shaped dihedral wing) 9 is variable according to the size and weight of the cargo, as shown in Figures 3 and 4. By adjusting the lift in this way, optimal horizontal flight can be achieved. The dihedral wing 9 divides the headwind 18 into airflow 22 that is evenly distributed to the left and right. When a forward tilt occurs and the aircraft is pushed backward in the direction of travel, it is less prone to lateral swaying and is pushed backward in a stable manner, allowing the wing 9 to gain lift and begin to float steadily. Furthermore, in the case of flight after cargo transport as shown in Figures 3b and 3d, when the container 10 is light, for example, empty, the wing 9 can be moved in direction 21, and as shown in Figures 3c and 3e, the dihedral angle of the flight wing 9 can be increased to reduce lift, making it less susceptible to the effects of various winds and resulting in flight that is less prone to container swaying due to airflow. Thus, when cargo is loaded or the weight is heavy, increasing the dihedral angle and making the wings larger increases lift. Conversely, when the cargo is light or the container is empty after cargo has been transported, reducing the dihedral angle and making the wings smaller decreases lift and makes the aircraft less susceptible to the effects of turbulent airflow. This contributes to improved safety as a risk management measure in preventing crashes.

[0026] In Figure 3b, compared to Figure 3c, not only is the area of ​​the wing 9 larger, but the aspect ratio (the ratio of length to width) is also higher. This is proportional to the improved wing performance, but it also reduces the stability in the pitch direction of the wing. The tailplane 11 plays a role in assisting the pitch stability of the main wing 9, and this effect increases as the distance from the main wing 9 increases. Therefore, as shown in Figures 3b and 3c, by arbitrarily adjusting the extension or retraction of the body frame 13 in accordance with the change in the dihedral angle of the main wing 9, the positional relationship between the tailplane and the main wing can be changed to improve flight stability. This improves stability. If a tail fin is not provided, stability can be achieved by sweeping back the main wing 9 and applying a "twist-down (reduced angle)" only to the angle of attack at the wingtips to give the wingtips the same effect as a tail fin. The variable dihedral angle section of the flight wing 9 can be realized, for example, by a mechanism that fastens and fixes the flight wing 9 with bolts and cap nuts of strut pins 8 (shown in detail in Figure 6). Furthermore, as shown in Figure 5, if the container 10 is mounted on the underside as a transport device, more stable flight becomes possible.

[0027] As described above, the flight mechanism according to the present invention makes it possible to fully utilize the advantages of drone transport, which eliminates the need for a runway, a certain amount of land area required for takeoff and landing, and dedicated maintenance, which were necessary for fixed-wing aircraft when transporting cargo.

[0028] Figure 6 shows an example of the structure of the dihedral angle variable mechanism for the flight wing 9 (main wing) in the flight mechanism of the present invention. Figures 6(a) and (b) show the state of the wing 9 with a large and small dihedral angle due to the dihedral angle variable mechanism of the main wing using strut pins, and Figures 6(c) and (d) show the external structure of the strut pin portion in Figures 6(a) and (b). This is a figure in which the dihedral angle of the main wing 9 is varied by the extension and contraction of a strut pin 8, one end of which is fixed to the upper frame bar 6 and the other end attached to the main wing 9. The strut pin 8 is fixed by inserting a bolt created in a part of it into a bolt hole 39 provided in the main wing 9 and screwing a cap nut 40 onto the bolt. The bolt extends and contracts and is fixed at an appropriate length by ball lock pins 41 and 42. The strut pin 8 is composed of sleeves 60 (L size), 70 (M size), and 80 (S size). Sleeve 80 (with holes 81 and 82) slides inside sleeve 70 (with holes 71 and 72), and sleeve 60 slides outside sleeve 70 (with holes 71 and 72). Ball lock pins 41 and 42 are inserted into the holes provided in each sleeve and fixed in place. As can be seen from Figure 7, which schematically shows the positional relationship and fixing status of the sleeves, the length of the strut pin 8 and the resulting dihedral angle can be varied depending on how each sleeve is fixed.

[0029] Figure 8 shows a specific structural example of the air cargo transport device of the present invention (equipped with additional devices for practical use). The front base bar 23 is attached to a base 45 provided on the drone side, and the rear base bar 23 is attached to a base 46 provided on the container side. As an additional device, an emergency parachute mechanism, an inner container containing a parachute 47, a pilot chute 49 connected to it, and a parachute launcher 50 is installed inside the outer container 48. In the event of an emergency landing, the pilot chute 49 and parachute 47 are launched from the parachute launcher 50 and deployed, enabling a safe landing. In addition, a case 51 containing a drone drive battery 53, a generator 52, and a propeller 54 is mounted as an additional device, and by rotating the propeller 54 with the wind during flight to charge the battery 53, the flight range of the air cargo transport device can be extended.

[0030] Figures 9 to 18 illustrate the operation and flight status of an air cargo transport device according to one embodiment of the present invention. Figure 9 shows the situation from takeoff from the ground to horizontal flight. Drone 1 ascends vertically from the ground in the direction of travel 32, lowers its nose in accordance with gravity and flies along path 56 to increase horizontal speed, ascends diagonally in the direction of travel 33, and then transitions to horizontal forward flight in the direction of travel 34.

[0031] Figure 10 shows, for example, the case where a headwind 30 is received in Figure 9. The lift generated on the main wing 9 of the container 10 by the headwind 30 reinforces the takeoff climb force, enabling efficient takeoff.

[0032] Figure 11 shows the drone 1 moving horizontally a short distance in the direction of travel 34 above the ground, then ascending diagonally in the direction of travel 33, and finally transitioning to horizontal forward movement in the direction of travel 34. In this case, a smooth running distance A is required on the ground, but since lift is generated on the wings 9 immediately after the drone 1 starts moving and begins to ascend, the smooth running distance A only needs to be a short distance of, for example, 10 to 30 meters, and a long runway is not required.

[0033] Figure 12 shows an air cargo transport device placed on a certain height (for example, a 10-30M high obstacle 36 (such as a building, hill, or plateau on a mountainside)), from which gravity is used to accelerate the drone 1's descent, and the lift from the wings 9 is also used to transition to horizontal forward flight. In this case, it is possible to achieve horizontal flight without requiring the energy needed for the drone 1's vertical takeoff.

[0034] Figure 13 shows a case where a headwind 30 blows against the shield 36, causing it to bounce up and generating an updraft 31. In this case, as is clear from the figure, the updraft 31 reduces the descent distance of the air cargo transport equipment, enabling a rapid horizontal transition, and also allows for a lower required height for the shield 36.

[0035] Furthermore, if a headwind 30 is blowing against the obstruction 36, causing it to bounce up and generating an updraft 31, as shown in Figure 14, utilizing the updraft 31 from near the bottom of the obstruction 36 to perform a vertical takeoff can reduce the energy required for the drone 1's vertical takeoff.

[0036] Figure 15 shows a case where a takeoff base frame 38 is installed on a simple shielding plate 37 for utilizing the updraft from the ground (0m), an air cargo transport device is placed on top of it, and the drone 1 is lifted using the updraft 31 generated from here, and then transitioned to horizontal forward flight using the lift from the wings 9. In this case, a cavity is formed in the base frame 38 through which the updraft 31 passes. In this case as well, it is possible to transition to horizontal flight while reducing the energy of the drone 1 during vertical takeoff.

[0037] Figure 16 shows a flight case combining Figures 14 and 15. As is clear from the figure, it becomes possible to utilize the powerful updraft 31 that is generated, enabling high-performance takeoff and further reduction of energy during takeoff.

[0038] Figure 17 shows the case in Figure 16 where the drone is taken off by flying in a continuous figure-eight direction 43 to keep it from drifting away from the updraft blown along the wind-exposed surface of the shield. The drone's maneuverability and the effective use of the updraft 31 enable high-performance takeoff.

[0039] Figure 18 shows the air cargo transport device of the present invention in a suspended state from horizontal flight. Fixed-wing aircraft currently used for cargo transport require high operational skills and a wide range of knowledge gained from accumulated experience, especially in handling excess altitude during landing rather than during takeoff. Cargo transport, in particular, where the wing loading is likely to change constantly, requires exceptionally high knowledge and operational skills. However, the present invention retains the characteristics of a multi-rotor drone that can descend vertically during landing, just as it does during vertical ascent during takeoff. The device of the present invention combines the advantages of horizontal flight of a fixed-wing aircraft with the characteristics of a multi-rotor drone, and by being able to descend vertically, it is possible to eliminate or significantly reduce the landing distance and lower the difficulty of landing.

[0040] The present inventors have considered suitable flight modes based on wind speed and cargo weight. Wind speed 0-1 m / s: If the payload is light relative to the drone's performance, see Figures 8 and 12. Wind speed 0-1 m / s: If the payload is at the upper limit of the drone's performance, see Figures 8, 10, and 12. Wind speed 2-3 m / s: If the payload is light or at the upper limit of the drone's performance, see Figures 9, 10, and 14. Wind speed 2-3 m / s: With upwind: If the payload is light relative to the drone's performance, see Figures 11, 12, and 15. Wind speed 2-3 m / s: With upwind: If the payload is at the upper limit of the drone's performance, see Figures 11, 12, and 16. Wind speed 4 m / s or more: If the payload is light or at the upper limit of the drone's performance, see Figures 9, 10, and 14. Wind speed 4 m / s or more: With upwind: If the payload is light relative to the drone's performance, see Figures 11, 12, and 16. If the wind speed is 4 m / s or higher, there is an updraft, and the payload is at the upper limit of the drone's performance, then Figures 11, 12, 15, and 16 represent suitable flight configurations.

[0041] The energy reduction effect is more easily understood in Figures 19, 20, and 21. The shaded area in (b) of each figure shows the total amount of energy consumed. That is, as is clear from Figure 19, which shows the energy consumption during flight with cargo loaded on a multi-rotor drone, and similar comparison figures 20 and 21 for the device of the present invention, the device of the present invention can achieve a significant reduction in energy consumption for the same cargo weight. This will have the exceptional effect of enabling longer-distance cargo transport even when using currently used multi-rotor drones. Naturally, a significant reduction in energy is possible for air transport over the same distance (especially longer distances).

[0042] We will now examine the towing function and effects of the device of the embodiment of the present invention described above. In aircraft, gliders (which do not have thrust and are operated independently by a pilot) are towed by a wire rope (an external force is applied to make them fly) and released in mid-air. In this case, the position control of the glider is performed by the pilot, so even with wire rope towing, stable flight of the towed glider is ensured by the pilot's independent operation. However, in the device of the present invention, which is based on unmanned flight, wire rope towing can result in unstable flight. Furthermore, if the two aircraft, the towing aircraft and the towed aircraft, are fixedly connected with exactly the same frame, there is an instability in which the tilt of the towing aircraft in an undesirable direction, known as the lockout phenomenon, which occurs during towing, gradually increases and the towing aircraft is also affected. As already mentioned, the two distance bars of the present invention shown in Figures 2 and 3 make it possible to eliminate such unstable flight in unmanned flight.

[0043] In the device according to the embodiment of the present invention described above, the effect of varying the upper half angle of the wing is examined. The main wing of the towed aircraft is intended to generate large lift. When an excessive load is applied in an undesired direction, or when lift is applied in an undesired direction, this influence in the undesired direction becomes a tilt and is transmitted as an unintentional tilting force to the towing aircraft. In the product of the present invention, the towed aircraft is provided with an upper half angle on its main wing, and unlike manned aircraft, it is highly likely to carry a large proportion of heavy cargo relative to the weight of the airframe. In drone transportation, significant weight changes are expected due to the weight of the loaded cargo or the loading and unloading of cargo on the outbound and return trips. Maintaining the same lift in this situation will generate an unnecessarily large force and cause adverse effects when the weight becomes light. Especially when passing through turbulence, when the wing loading is low compared to when the wing loading is high, the aircraft tends to be at the mercy of the effects caused by wind. As already mentioned, being able to change the upper half angle of the flying wing of the present invention can eliminate and mitigate the above-mentioned problems.

[0044] In conventional aircraft, there exist aircraft with variable main wing angle of attack, such as the Osprey, which is famous for being used as a US military aircraft, or the Douglas Harrier. However, it is considered that there is no practical example of an aircraft having a function of varying the upper half angle of a wing. The reason is that manned aircraft, including those for passenger and cargo transportation, have a large total weight, and their horizontal wings have a large area and a sturdy structure, so varying the upper half angle of the wing has not been considered in the first place. Furthermore, according to studies conducted by the present inventor, aircraft with a large total weight are less susceptible to changes in airflow, and the effect of varying the upper half angle of the wing is unlikely to be significant. The air cargo transportation device of the present invention is unmanned, has no drive mechanism, and enables the use of a transportation container that is much lighter than that of the aforementioned manned aircraft. This makes it susceptible to influences such as turbulence during flight. The air cargo transportation device of the present invention can be equipped with a wing having a relatively much smaller area than that of the aforementioned manned aircraft, which makes it easy to realize varying the upper half angle of the wing, thereby enabling the reduction of unstable flight caused by airflow and other factors.

[0045] Current reports on drone-based cargo transport experiments show that multi-rotor aircraft are the mainstream, and due to the characteristics of their small-diameter propellers, the cargo that can be transported is limited to lightweight items. From the perspective of profitability as a business model, multi-rotor aircraft are unsuitable. According to the present invention, it is possible to improve lift without compromising operability, improving the transport capacity of multi-rotor drones, thereby increasing profitability through the expanded use of existing multi-rotor drones, and at the same time, the vertical ascent function of the drone makes it possible to dramatically extend the transport distance from locations without runways. As is clear from the above explanation, the present invention realizes a horizontal flight mechanism in which the drone and the cargo-carrying aircraft are integrated, making it possible to use existing drones, and provides an air cargo transport device that does not require a large runway area and enables long-duration, long-distance cargo air transport.

[0046] 1. Multi-rotor drone body 4. Distance bar 6. Upper frame bar 7. Lower frame bar 8. Strut pin 9. Tail fin (dihedral V-shaped wing) 10. Cartridge-type container 11. Tail fin (dihedral V-shaped wing) 23. Front base bar 24. Rear base bar 25. Wire cable 29. Drone flight direction 30. Headwind 31. Updraft caused by wind bouncing up after hitting an obstacle 32. Drone flight direction (vertical ascent direction)

Claims

1. An air cargo transport device comprising: a transport container equipped with a flight wing capable of carrying cargo and having a variable dihedral angle; a drive aircraft that tows the transport container; and a connecting body that connects the transport container and the drive aircraft, wherein one end of the connecting body is attached to the drive aircraft and the other end of the connecting body is attached to the transport container, the drive aircraft takes off the transport container, and during parallel towing flight, the transport container and the drive aircraft fly by obtaining lift from the flight wing, the dihedral angle of the flight wing during towing is set according to the weight of the cargo, and the connecting body operates according to the behavior of the drive aircraft.

2. The air cargo transport device according to claim 1, characterized in that the driven aircraft consists of a multi-rotor drone.

3. The air cargo transport device according to claim 1, wherein when the transport container lands, the transport container is suspended and landed by the driven aircraft.

4. The air cargo transport device according to claim 2, wherein, when the transport container takes off, the transport container is positioned at a point where it receives airflow.

5. The air cargo transport device according to claim 1, wherein the driving aircraft consists of a multi-rotor drone, the connecting body consists of a pair of left and right distance bars attached to the multi-rotor drone, and the pair of left and right distance bars are moved independently in accordance with the behavior of the multi-rotor drone.

6. The air cargo transport device according to claim 5, wherein the pair of left and right distance bars have an S-shape with semicircular portions of different diameters.

7. The air cargo transport device according to claim 5, wherein a base bar is connected to the left and right pair of distance bars, and the connection portion between the distance bars and the base bar is provided with an up-down and left-right movable connection portion for the left and right pair of distance bars.

8. The air cargo transport device according to claim 7, wherein the vertically and horizontally movable connecting portion is provided with an opening in a part of the pair of left and right distance bars and a wire cable portion passing through the opening, and the part of the pair of left and right distance bars is movable vertically and horizontally.

9. The air cargo transport device according to claim 1, characterized in that the flight wing consists of a main wing and a tail wing, and is connected by a body frame of variable length between the main wing and the tail wing.

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