A tilt-rotor UAV

Abstract

The invention discloses a tilt-rotor unmanned aerial vehicle, comprising a fuselage (1), wherein a wing driving mechanism (10) is arranged in the fuselage (1), a rotating shaft (2) is arranged on the fuselage (1), wings (3) are arranged on both sides of the fuselage (1), the ends of the rotating shaft (2) are connected to the wings (3) via a rotating mechanism (50), a propeller (4) is arranged on the rotating mechanism (50), the rotating mechanism (50) comprises a bracket (500), the rotating shaft (2) is connected to the propeller (4) via the bracket (500), a spring (505) is arranged between the bracket (500) and the wing (3), a rotating motor (501) is arranged on the bracket (500), a first rotating rod (502) is arranged at the output end of the rotating motor (501), a second rotating rod (503) is hingedly connected to the end of the first rotating rod (502), and the second rotating rod (503) is rotatably connected to the wing (3) via a first hinge seat (504). The invention has the advantages of long service life, good endurance, less prone to flight accidents and simple maintenance.

Description

Technical Field

[0001] The invention belongs to the field of tilt-rotor unmanned aerial vehicles. Background Art

[0002] The structure of the existing tilt-rotor UAV (hereinafter referred to as UAV) includes a fuselage 1, a fuselage 1 A wing drive mechanism is provided inside, a rotating shaft 2 connected to the wing drive mechanism is horizontally crossed on the fuselage 1, wings 3 are provided on both sides of the fuselage 1, the ends of the rotating shaft 2 are connected to the wings 3 through a rotating mechanism, a propeller 4 is provided on the rotating mechanism, and the propeller 4 is always located at the front side of the wing 3, the wing drive mechanism can drive the wing 3 to rotate around the rotating shaft 2 through the rotating shaft 2, and the rotating mechanism can drive the wing 3 to rotate, so that the wing 3 can achieve universal rotation; a rotatable aileron 5 is provided on the rear side of the wing 3, a horizontal tail 6 is provided on the rear side of the fuselage 1, a vertical tail 7 is provided on the top of the horizontal tail 6, a rotatably connected elevator 8 (with an elevator control system) is provided on the rear side of the horizontal tail 6, and the elevator 8 is used to change the pitch flight state of the drone, and tail rotors 9 are provided on the horizontal tail 6 and the vertical tail 7. A wing control system, an aileron control system and a tail rotor control system are provided in the fuselage 1, the wing control system controls the rotation of the wing 3, the aileron control system controls the rotation of the aileron 5, and the tail rotor control system controls the rotation speed of the tail rotor 9. The flight attitude of the drone includes level flight and hovering. The drone takes off and lands in the hovering state, using the wings on both sides as landing gear during takeoff and landing.

[0003] Existing drones have a rigid structure as a whole, and the existing technology cannot achieve a smooth and slow landing. If they land at a fast speed, they will collide with the ground and generate impact force. The impact force is transmitted to the rotating mechanism through the wings, which can easily cause the rotating mechanism to malfunction, thus shortening the service life of the drone.

[0004] The existing wing drive mechanism includes a drive motor 100 (also known as a steering gear) with a self-locking force. The drive motor 100 is provided with a driving gear, and the driving gear is connected to the rotating shaft 2 through a passive gear. The drive motor 100 drives the rotating shaft 2 to rotate in one direction through the driving wheel and the passive wheel. When the drone is in a stable level flight state, the state of the wing 3 remains unchanged. The wing 3 is affected by the airflow and has a rotation tendency. The force on the wing 3 is transmitted to the drive motor 100 through the rotating mechanism 50, the rotating shaft 2, the passive gear and the driving gear, and is overcome by the locking force of the drive motor 100 itself. That is to say, during the stable level flight of the drone, the drive motor 100 is subjected to force for a long time, which makes the drive motor 100 easy to damage. The drive motor 100 provides a self-locking force with its own stall torque. Taking the drive motor 100 with an operating voltage of 6V and a stall torque of 20kg.cm as an example, the service life is 2800-3500 hours. Moreover, when the drone flies at high speed, the wing 3 is subjected to great force, which may lead to insufficient locking force of the drive motor 100, causing the state of the wing 3 to change, the flight attitude of the drone to be out of control, and thus cause a flight accident.

[0005] The active gear and the passive gear (gear pair) in the existing wing drive mechanism require very precise matching, otherwise the wing 3 is prone to vibrate, which puts high demands on processing and installation, thereby making the manufacturing cost of the existing wing drive mechanism relatively high.

[0006] The existing wing drive mechanism has high requirements for the use environment. In order to prevent dust from entering the gear pair and causing jamming, it is necessary to set a dustproof box cover on the outside of the wing drive mechanism, which increases the weight and causes greater wind resistance, which greatly reduces the endurance of the drone. It is also necessary to add lubricating oil regularly, which is more troublesome to maintain. In addition, the existing wing drive mechanism is only used when the drive motor 100 is close to the rotating shaft 2, and the scope of application is relatively small. In addition, the gear pair is rigidly connected, with poor impact resistance and shock absorption, which makes the gear pair prone to problems such as tooth breakage, tooth pitting, tooth wear, tooth bonding and plastic deformation, resulting in a short service life. Taking the gear pair made of aviation aluminum alloy as an example, the service life is only about 10,000 hours.

[0007] The existing flight control method of the UAV includes controlling the UAV in a level flight state to perform a tumbling action, controlling the UAV in a hovering state to move forward, backward and turn,

[0008] When the drone is in level flight, the wing 3 remains horizontal and its long direction is perpendicular to the fuselage 1, and the aileron 5 is parallel to the wing 3. Fig.15As shown, the two ailerons 5 are rotated upward and downward respectively through the aileron control system, and an angle is formed between them and the wing 3, so that the downwash airflow generated by the propeller 4 generates forces in different directions on the two ailerons 5, thereby generating a rolling moment, causing the drone to roll, but the corresponding aileron 5 causes the downwash airflow to slow down, reducing the thrust on the drone, so that the propeller 4 must increase a lot of power to maintain the original flight speed, resulting in poor endurance of the drone. In addition, when the drone is flying at high speed, it may also cause "aileron counter-effect" and the drone cannot be controlled.

[0009] When the drone is in a hovering state, the wing 3 remains in a vertical state and its long direction is perpendicular to the fuselage 1. When the drone is turned, Fig.16 As shown, the two ailerons 5 are rotated front and rear respectively by the aileron control system, so that the downwash airflow of the propeller 4 generates components of different directions on the two ailerons 5, thereby generating a first torque. At the same time, the tail rotor control system controls the tail rotor 9 on the horizontal tail 6 to change the rotation speed, thereby generating a second torque. Under the action of these two torques, the UAV turns. Since the tilt of the aileron 5 hinders the flow of the downwash airflow, the speed of the downwash airflow is reduced, and the lift of the UAV is reduced, so it is necessary to increase the rotation speed of the propeller 4 to maintain the hovering state of the UAV, which leads to a reduction in the flight time of the UAV.

[0010] When the drone is controlled to move forward or backward, the tail rotor 9 on the horizontal tail wing 6 is changed by the tail rotor control system. The lift of the tail rotor 9 changes, the rear end of the drone rises or falls, and the drone forms an angle with the ground. The drone is in a dive or tilted state, so that the downwash airflow of the propeller 4 also forms an angle with the ground, generating a horizontal driving force component to push the drone forward or backward. However, this also leads to a reduction in the thrust of the drone to maintain hovering, so the speed of the propeller 4 must be increased to maintain the hovering state of the drone, the power of the drone increases, and the endurance time decreases. In addition, the windward surface of the wing 3 is large in the hovering state, which makes the drone have a large resistance to moving forward and backward, and also leads to a reduction in the endurance time of the drone. In addition, in windy weather, the wing 3 is greatly affected by the wind, making it difficult to maintain the stability of the drone.

[0011] The implementation of the existing UAV control method requires the UAV to have a tail rotor 9, ailerons 5, an aileron control system and a tail rotor control system. The large number of parts leads to a large total weight of the UAV, and thus poor endurance; and the structures of the aileron control system and the tail rotor control system are very complicated, which makes the UAV prone to malfunction.

[0012] Therefore, existing drones have the defects of short service life, poor endurance, prone to flight accidents and troublesome maintenance. Summary of the invention

[0013] The purpose of the present invention is to provide a tilt-rotor unmanned aerial vehicle having the advantages of long service life, good endurance, low probability of flight accidents and simple maintenance.

[0014] The technical solution of the present invention is as follows: a tilt-rotor UAV comprises a fuselage, a wing driving mechanism is arranged in the fuselage, a rotating shaft connected to the wing driving mechanism is horizontally crossed on the fuselage, wings are arranged on both sides of the fuselage, the ends of the rotating shaft are connected to the wings through a rotating mechanism, a propeller is arranged on the rotating mechanism, the rotating mechanism comprises a bracket, the rotating shaft is connected to the propeller through the bracket, the bracket is rotatably connected to the wing, a spring is arranged between the bracket and the wing, a rotating motor is arranged on the bracket, a first rotating rod is arranged at the output end of the rotating motor, a second rotating rod is hinged at the end of the first rotating rod, and the second rotating rod is rotatably connected to the wing through a first hinge seat.

[0015] In the aforementioned tilt-rotor UAV, a rotating shaft is provided between the bracket and the wing, a shaft sleeve is provided on the bracket through which one end of the rotating shaft passes, a second hinge seat is provided on the wing through which the other end of the rotating shaft passes, and a spring is provided between the shaft sleeve and the second hinge seat and is sleeved on the rotating shaft.

[0016] In the aforementioned tilt-rotor UAV, a rotating shaft is provided between the bracket and the wing, a shaft sleeve is provided on the bracket through which the middle of the rotating shaft passes, and two second hinge seats are provided on the wing through which the two ends of the rotating shaft pass respectively, and a spring is provided between one of the second hinge seats and the shaft sleeve.

[0017] In the aforementioned tilt-rotor UAV, the wing drive mechanism includes a drive motor fixed in the fuselage, a first rotating rod is provided at the output end of the drive motor, the first rotating rod is connected to the third rotating rod through a second rotating rod with adjustable length, and a ring is provided at the end of the third rotating rod for connecting to the rotating shaft.

[0018] In the aforementioned tilt-rotor UAV, both ends of the second rotating rod are provided with threads, and the threads at both ends of the second rotating rod have opposite rotation directions. Both ends of the second rotating rod are screwed with threaded sleeves, one of which is rotatably connected to the first rotating rod, and the other threaded sleeve is rotatably connected to the third rotating rod.

[0019] In the aforementioned tilt-rotor UAV, one of the screw sleeves is rotatably connected to the first rotating rod via a first bearing, and the other screw sleeve is rotatably connected to the third rotating rod via a second bearing.

[0020] In the aforementioned tilt-rotor UAV, the ring is provided with an opening, and the two sides of the opening extend outward to form a first connecting part and a second connecting part respectively, and the first connecting part is provided with a step hole, and the end of the third rotating rod abuts against the bottom surface of the step hole, and the end of the third rotating rod extends toward the second connecting part and is screwed with the second connecting part.

[0021] In the aforementioned tilt-rotor UAV, the third rotating rod is provided with a through slot, and at least two through holes are provided corresponding to the through slot, wherein a rotating pin is provided in one of the through holes, and the third rotating rod is rotatably connected to the second rotating rod via the rotating pin.

[0022] In the aforementioned tilt-rotor UAV, the middle portion of the second rotating rod bulges outward to form a polygonal column.

[0023] In the aforementioned tilt-rotor UAV, the flight control method of the UAV controls the following actions of the UAV:

[0024] Lateral roll: Keep the drone in level flight. In the level flight state, the wings are kept horizontal and the long direction is perpendicular to the fuselage. The sideways roll of the drone is achieved by adjusting the vertical angle between the two wings.

[0025] Steering: Keep the drone in a hovering state. In the hovering state, the wings are kept vertical and the long direction is parallel to the fuselage. The steering of the drone is achieved by adjusting the angle between the wings and the fuselage 1.

[0026] Fly forward at low speed: Keep the drone in a hovering state, move the front ends of the two wings closer to the inside, and achieve low-speed forward flight of the drone;

[0027] Slow-speed backward flight: Keep the drone in a hovering state, move the rear ends of the two wings closer to the inside, and achieve low-speed backward flight of the drone.

[0028] In the aforementioned tilt-wing UAV, the lateral roll is to keep the UAV in a level flight state, by deflecting the right wing of the UAV so that the inner end of the right wing is tilted upward, thereby realizing the right roll of the UAV; by deflecting the left wing so that the inner end of the left wing is tilted upward, thereby realizing the left roll of the UAV.

[0029] In the aforementioned tilt-wing UAV, in the lateral rolling, the angular acceleration of the UAV rolling to the right is changed by changing the deflection angle of the right wing; and the angular acceleration of the UAV rolling to the left is changed by changing the deflection angle of the left wing.

[0030] In the aforementioned tilt-rotor UAV, the steering is to keep the UAV in a hovering state, synchronously deflect the front ends of the two wings to the left to realize the left turn of the UAV; synchronously rotate the front ends of the two wings to the right to realize the right turn of the UAV.

[0031] In the aforementioned tilt-rotor UAV, during the steering, the angular acceleration of the UAV turning left is changed by changing the angle of deflection of the two wings to the left; the angular acceleration of the UAV turning right is changed by changing the angle of deflection of the two wings to the right.

[0032] In the aforementioned tilt-rotor UAV, the low-speed forward flight is to keep the UAV in a hovering state, bring the front inner sides of the two wings closer together, and keep the two wings distributed in a mirror image with respect to the fuselage 1, so as to achieve the low-speed forward flight of the UAV.

[0033] In the aforementioned tilt-rotor UAV, during the low-speed forward flight, the flight angular acceleration of the UAV is changed by changing the angle between the two wings.

[0034] In the aforementioned tilt-rotor UAV, the low-speed backward flight is to keep the UAV in a hovering state, move the rear ends of the two wings inward synchronously, and keep the two wings mirror-distributed with respect to the fuselage 1, so as to achieve the low-speed backward flight of the UAV.

[0035] In the aforementioned tilt-rotor UAV, during the low-speed backward flight, the flight angular acceleration of the UAV is changed by changing the angle between the two wings.

[0036] Compared with the prior art, the present invention is an improvement on the existing UAV, mainly in terms of the improvement of the rotating mechanism, wing drive mechanism and flight control method. The rotating mechanism of the present invention has a spring, so that when the UAV lands, the impact force generated by the collision with the ground is absorbed by the spring, reducing the impact force. According to experimental calculations, the impact force can be reduced by 35%, making the rotating mechanism less prone to failure, and the average service life of the rotating mechanism can be increased by 50%, thereby increasing the service life of the UAV.

[0037] The wing drive mechanism of the present invention forms a four-bar linkage between the drive motor and the rotating shaft through the first rotating rod, the second rotating rod and the third rotating rod. The four-bar linkage has a self-locking ability, that is, when the UAV is in stable level flight (at this time, the wing length is perpendicular to the fuselage and the wing width is parallel to the flight direction), the four-bar linkage is in a self-locking state, which can prevent the rotating shaft from rotating, thereby avoiding the drive motor from being stressed. The drive motor is only stressed when working, that is, the drive motor is only stressed when the UAV changes its flight attitude, thereby greatly reducing the stress time, making the drive motor less likely to be damaged. Taking a drive motor with an operating voltage of 6V and a stall torque of 20kg.cm as an example, the service life can be extended to 5000-6000 hours. Since the four-bar linkage can lock the rotating shaft, and the locking force of the drive motor can also provide the rotating shaft with an additional locking force, it is ensured that the rotating shaft will not rotate when the UAV is in stable level flight, so that the flight attitude of the UAV will not change, and it is not easy to cause a flight accident.

[0038] The wing drive mechanism of the present invention uses multiple connecting rods to connect the rotating shaft and the output end of the driving motor. The manufacturing accuracy of the connecting rods is easy to ensure, the manufacturing difficulty is low, the installation difficulty is low, and the matching requirements are also low, thereby reducing the manufacturing cost of the wing drive mechanism.

[0039] The wing drive mechanism of the present invention has low requirements for the use environment, and dust is not easy to enter between the rotating rods, so there is no need for dust prevention, and there is no need to install a dustproof box cover. The weight of the wing drive mechanism is reduced and the wind resistance is small, which can improve the endurance of the UAV. The movable end of the rotating rod is a surface contact low-pair connection, which is not easy to wear and is easy to lubricate, thereby greatly extending the lubricating oil addition cycle and making maintenance easier. In addition, the wing drive mechanism of the present invention can adapt to different distances between the drive motor and the rotating shaft by changing the length of the rotating rod, and has a wide range of applications. In addition, the multiple rotating rods are flexibly connected in rotation, so that the impact resistance and shock absorption of the wing drive mechanism are better, and the service life of the wing drive mechanism is longer, with a service life of 15,000-20,000 hours.

[0040] The flight control method of the present invention rotates the wings to make the two wings form an angle in the direction of the wing length, so that the lift between the two wings is different, generating torque, and causing the UAV in a level flight state to roll. During this process, the ailerons maintain a parallel state with the wings, the downwash air flow speed of the propeller remains unchanged, and the thrust of the UAV is basically unchanged, so there is no need to increase a lot of power to maintain the original flight speed, thereby improving the endurance of the UAV. Since the ailerons are not used in the rolling action, the ailerons continue to remain parallel to the wings during the rolling process, and when the UAV flies at high speed, no "aileron counter-effect" will be generated, and the maneuverability of the UAV is guaranteed.

[0041] The present invention rotates the wing so that the wing has an angle with the fuselage, so that the downwash airflow generated by the propeller is generally biased to one side, so that the thrust of the downwash airflow pushing the wing has an angle with the fuselage, thereby pushing the UAV in the hovering state to turn. Since the steering action does not use the aileron, the aileron maintains a parallel state with the wing, the downwash airflow speed of the propeller remains unchanged, and the thrust of the UAV is basically unchanged, so there is no need to increase a lot of power to maintain the original flight speed, so that the endurance of the UAV is improved.

[0042] The present invention changes the angle between the two wings of the drone in the hovering state so that the downwash airflow of the propeller has different intensities at the front and rear sides, thereby making the driving force at the front and rear sides of the drone different, so that the drone moves forward or backward at a low speed. In this process, the drone maintains a horizontal state, the lift does not change, there is no need to increase the speed of the propeller to maintain the hovering state of the drone, the power of the drone does not increase, and the endurance time does not decrease. In addition, the windward surface of the wing in the hovering state is small, so that the resistance of the drone moving forward and backward is small, so that the endurance time of the drone is increased, and in windy weather, the wings are less affected by the wind, so it is easy to maintain the stability of the drone.

[0043] The implementation of the present invention does not require the participation of tail rotor and aileron, so the tail rotor, aileron, aileron control system and tail rotor control system equipped on the UAV can be removed accordingly, thereby reducing the number of parts, reducing the total weight of the UAV, further improving the endurance, and being less prone to failure.

[0044] According to actual tests, the battery life of the battery pack is increased by 28% and the failure rate is reduced by 35%.

[0045] Therefore, the present invention has the advantages of long service life, good endurance, less prone to flight accidents and simple maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the level flight state of the UAV of the present invention.

[0047] Figure 2 It is a schematic diagram of the hovering state of the drone of the present invention.

[0048] Figure 3 It is a schematic structural diagram of the rotating mechanism of Example 1.

[0049] Figure 4 It is a structural diagram of the wing drive mechanism.

[0050] Figure 5 It is a schematic diagram of the wing drive mechanism in the self-locking state.

[0051] Figure 6 It is the force analysis diagram of the four-bar linkage on the wing drive mechanism.

[0052] Figure 7 It is a schematic diagram of the structure of the wing of Example 2 when viewed from above.

[0053] Figure 8 It is a schematic diagram of the structure of the wing of Example 2 when viewed from above.

[0054] Fig. 9 It is a schematic diagram of the installation of the wing of Example 2.

[0055] Fig.10 It is a schematic diagram of the structure of the rotating mechanism of Example 2.

[0056] Fig.11 It is a top view schematic diagram of the unmanned aerial vehicle of the present invention when rolling to the right in a level flight state.

[0057] Fig.12 It is a top view schematic diagram of the drone of the present invention when turning left in a hovering state.

[0058] Fig.13 It is a top view schematic diagram of the drone of the present invention flying forward at a low speed in a hovering state.

[0059] Fig.14 It is a top view schematic diagram of the drone of the present invention flying backward at a low speed in a hovering state.

[0060] Fig.15 It is a schematic diagram of an existing UAV rolling in a level flight state under an existing flight control method.

[0061] Fig.16 It is a schematic diagram of the steering of an existing UAV in a hovering state under an existing flight control method.

[0062] The markings in the accompanying drawings are: 1-fuselage, 2-rotating shaft, 3-wing, 4-propeller, 5-aileron, 6-horizontal tail, 7-vertical tail, 8-elevator, 9-tail propeller;

[0063] 10-wing drive mechanism, 100-drive motor, 101-first rotating rod, 102-second rotating rod, 103-third rotating rod, 2-rotating shaft, 105-collar, 106-screw sleeve, 107-first bearing, 108-second bearing, 109-polygonal column, 110-opening, 111-first connecting part, 112-second connecting part, 113-step hole, 114-through groove, 115-through hole, 116-rotating pin, 117-first connecting rod, 118-second connecting rod, 119-third connecting rod, 120-fourth connecting rod, 121-shaft sleeve;

[0064] 50 - rotating mechanism, 500 - bracket, 501 - rotating motor, 502 - first rotating rod, 503 - second rotating rod, 504 - first hinge seat, 505 - spring, 506 - rotating shaft, 507 - shaft sleeve, 508 - second hinge seat.

[0065] 60-keel, 61-carbon fiber plate, 62-aluminum alloy tube, 63-camera mounting base, 64-screw. DETAILED DESCRIPTION

[0066] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0067] Embodiment 1. A tilt-rotor drone, such as Figure 1 and Figure 2 As shown, it includes a fuselage 1, a horizontal tail 6 is provided on the rear side of the fuselage 1, a vertical tail 7 is provided on the top of the horizontal tail 6, an elevator 8 is provided on the rear side of the horizontal tail 6 for rotation connection, a wing driving mechanism 10 is provided inside the fuselage 1, a rotating shaft 2 connected to the wing driving mechanism 10 is horizontally crossed on the fuselage 1, the rotating shaft 2 is rotationally connected to the fuselage 1, wings 3 (existing wings) are provided on both sides of the fuselage 1, the ends of the rotating shaft 2 are connected to the wings 3 through a rotating mechanism 50, and a propeller 4 is provided on the rotating mechanism 50.

[0068] The fuselage 1 includes a keel 60, the rear end of the keel 60 is fixed to the horizontal tail 6, and the front end of the keel 60 is provided with a rectangular frame, and the wing drive mechanism 10 is fixed in the rectangular frame. The rectangular frame includes two upper and lower carbon fiber plates 61, and the two carbon fiber plates 61 are fixed by an aluminum alloy tube 62. A camera mounting seat 63 with a sliding connection is provided on the keel 60, and the camera mounting seat 63 is passed through the keel 60 and fixed to the keel 60 by screws 64. When the drone uses the camera mounting seat 63 to install a camera, the center of gravity can be adjusted by adjusting the position of the camera mounting seat 63 on the keel 60, so that the balance adjustment range of the drone is increased, and the adjustment range is increased by 30%-50%.

[0069] like Figure 3 As shown, the rotating mechanism 50 includes a bracket 500, the rotating shaft 2 is connected to the propeller 4 through the bracket 500, the bracket 500 is rotationally connected to the wing 3, a spring 505 is provided between the bracket 500 and the wing 3, a rotating motor 501 is provided on the bracket 500, and a first rotating rod 502 is provided at the output end of the rotating motor 501, a second rotating rod 503 is hinged at the end of the first rotating rod 502, and the second rotating rod 503 is rotationally connected to the wing 3 through a first hinge seat 504.

[0070] A rotating shaft 506 is provided between the bracket 500 and the wing 3, a shaft sleeve 507 is provided on the bracket 500 through which one end of the rotating shaft 506 passes, a second hinge seat 508 is provided on the wing 3 through which the other end of the rotating shaft 506 passes, and a spring 505 is provided between the shaft sleeve 507 and the second hinge seat 508 and is sleeved on the rotating shaft 506.

[0071] The working principle of the rotating mechanism 50 is as follows: the rotating motor 501 drives the wing 3 to rotate around the rotating shaft 506 through the first rotating rod 502, the second rotating rod 503 and the first hinge seat 504 in sequence. In embodiment 1, the rotating mechanism 50 has only two hinge seats, which is suitable for thinner wings 3 and has lower cost.

[0072] like Figure 4-Figure 5 As shown, the wing drive mechanism 10 includes a drive motor 100 fixed in the fuselage 1, and a first rotating rod 101 is provided at the output end of the drive motor 100. The first rotating rod 101 is connected to a third rotating rod 103 through a second rotating rod 102 with adjustable length. The end of the third rotating rod 103 is provided with a ring 105 for connecting to the rotating shaft 2, and the rotating shaft 2 is rotatably connected to the fuselage 1 through a shaft sleeve 121.

[0073] Both ends of the second rotating rod 102 are provided with threads, and the threads at both ends of the second rotating rod 102 have opposite rotation directions. Both ends of the second rotating rod 102 are screwed with threaded sleeves 106, one of which is rotatably connected to the first rotating rod 101, and the other threaded sleeve 106 is rotatably connected to the third rotating rod 103.

[0074] One of the screw sleeves 106 is rotatably connected to the first rotating rod 101 via a first bearing 107 , and the other screw sleeve 106 is rotatably connected to the third rotating rod 103 via a second bearing 108 .

[0075] The middle portion of the second rotating rod 102 bulges outward to form a polygonal column 109 .

[0076] The collar 105 is provided with an opening 110, and the two sides of the opening 110 extend outward to form a first connection portion 111 and a second connection portion 112, respectively. The first connection portion 111 is provided with a step hole 113, and the end of the third rotating rod 103 abuts against the bottom surface of the step hole 113, and the end of the third rotating rod 103 extends toward the second connection portion 112 and is screwed with the second connection portion 112. After the third rotating rod 103 is tightened, it drives the first connection portion 111 to move closer to the second connection portion 112, so that the collar 105 is clamped on the rotating shaft 2.

[0077] The third rotating rod 103 is provided with a through slot 114 , and two through holes 115 are provided corresponding to the through slot 114 , and a rotating pin 116 is provided in one of the through holes 115 . The rotating pin 116 is a plug screw. The third rotating rod 103 is rotatably connected to the second rotating rod 102 via the rotating pin 116 , and the rotating pin 116 passes through the second bearing 108 .

[0078] The working principle of the wing drive mechanism 10 is as follows: the second rotating rod 102 is rotated by the polygonal column 109. Since the spiral rotation directions of the two ends of the second rotating rod 102 are opposite, the screw sleeves 106 at the two ends of the second rotating rod 102 are close to or away from each other, thereby changing the length of the second rotating rod 102. The wing drive mechanism is formed with a four-bar linkage, the first link 117 is formed between the rotating shaft 2 and the output end of the driving motor 100, the second link 118 is formed between the output end of the driving motor 100 and the first bearing 107, the third link 119 is formed between the first bearing 107 and the second bearing 108, and the fourth link 120 is formed between the second bearing 108 and the rotating shaft 2. The length of the third link 119 is changed by changing the length of the second rotating rod 102, and the length of the fourth link 120 is changed by placing the rotating pin 116 on different through holes 115, so that the lengths of two of the links in the four-bar linkage are adjustable, ensuring. The length of the first connecting rod 117 is D, the length of the second connecting rod 118 is C, the length of the third connecting rod 119 is B, and the length of the fourth connecting rod 120 is A. By adjusting the lengths of the third connecting rod 119 and the fourth connecting rod 120, A 2 +(BC)2=D 2 .

[0079] When the UAV is in level flight, the wing drive mechanism is in the following state when viewed from the side of the UAV: Figure 5As shown, the state of the four-bar linkage is as follows: Figure 6 As shown, the fourth connecting rod 120 is perpendicular to the third connecting rod 119, and the third connecting rod 119 is colinear with the second connecting rod 118. At this time, the force of the wing against the wind is transmitted to the rotating shaft 2, so that the rotating shaft 2 has a tendency to rotate, and the rotating shaft 2 drives the second bearing 108 to have a tendency to rotate around the rotating shaft 2. Since the third connecting rod 119 is colinear with the second connecting rod 118 and the position of the driving motor 100 is fixed, the rotation tendency of the second bearing 108 is overcome, and the rotating shaft 2 cannot rotate, thereby achieving self-locking.

[0080] When the drone switches to the hovering state, the driving motor 100 drives the second connecting rod 118 to rotate, and the second connecting rod 118 drives the rotating shaft 2 to rotate through the third connecting rod 119 and the fourth connecting rod 120 in turn. The rotating shaft 2 drives the wing to rotate in one direction through the wing driving mechanism to achieve the switching of the flight attitude.

[0081] The structural difference between the wing drive mechanism of the present invention and the wing drive mechanism of the existing UAV is that the present invention drives the rotating shaft 2 to rotate through a plurality of rotating rods hinged in sequence, while the existing wing drive mechanism drives the rotating shaft 2 to rotate through a gear pair.

[0082] Embodiment 2. Different from Embodiment 1, Fig.10 As shown, a rotating shaft 506 is provided between the bracket 500 and the wing 3, a shaft sleeve 507 is provided on the bracket 500 and is passed through by the middle of the rotating shaft 506, and two second hinge seats 508 are provided on the wing 3 and are passed through by two ends of the rotating shaft 506, respectively, and a spring 505 is provided between one of the second hinge seats 508 and the shaft sleeve 507. In embodiment 2, the rotating mechanism 50 has three hinge seats, which has better structural strength and is suitable for thicker wings 3, but has higher cost.

[0083] like Figures 7 and 8 As shown, the wing 3 is thick at the front and thin at the back, and the wing 3 is a hollow structure. A recessed portion 300 is provided on the bottom surface of the wing 3, and the recessed portion 300 passes through the front and rear ends of the wing 3. A groove 301 is provided on one side of the recessed portion 300, and the groove 301 passes through the inner end of the wing 3.

[0084] The front end of the wing 3 is an arc surface 302, and the cross section of the groove 301 is semicircular.

[0085] A first plane 303 is provided at the bottom of the wing 3, and a second plane 304 is provided at the top surface of the wing 3. The front end of the first plane 303 is connected to the front end of the second plane 304 through an arc surface 302. A first downwardly inclined surface 305 and a second downwardly inclined surface 306 are provided in sequence on the rear side of the second plane 304. A bulge 307 corresponding to the recessed portion 300 is provided on the second inclined surface 306, and the top surface of the bulge 307 is flush with the first inclined surface 305.

[0086] The length-to-width ratio of the wing 3 is 3.5-4.5, and the length-to-thickness ratio of the wing 3 is 450-500.

[0087] like Fig. 9 As shown, the rotating mechanism 50 is installed on the bottom surface of the recessed portion 300, the groove 301 matches the rotating shaft 2, and the upper part of the rotating shaft 2 is inserted into the groove 301. The recessed portion 300 is used to shorten the distance between the rotating shaft 2 and the bottom surface of the wing 3, so that the upper part of the rotating shaft 2 can be hidden in the wing 3.

[0088] In Example 2, the wing 3 is improved. Since the wing 3 is a hollow structure, when the UAV lands on the water, the wing 3 can provide buoyancy, so that the UAV can take off and land on the water, thereby making the UAV have a wider range of applications. A groove 301 is provided on the bottom surface of the wing 3, and the upper part of the shaft 2 is hidden in the groove 301, so that when the UAV flies horizontally, the shaft 2 is exposed less, and the combination of the exposed part and the wing 3 is smoother, and the wind resistance is small, thereby improving the endurance of the UAV. In addition, the wing 3 is further optimized, further reducing wind resistance, and further improving the endurance of the UAV.

[0089] In the flight control method of the UAV in the above two embodiments, the rotation directions of the two propellers 4 on the left wing 3 and the right wing 3 are as follows: Figure 1 and Figure 2 As shown by the middle arrow, the following actions of the drone are controlled in accordance with the existing drone.

[0090] Lateral roll: keep the drone in a level flight state. In the level flight state, the wing 3 remains horizontal and its long direction is perpendicular to the fuselage 1. The left wing 3 remains horizontal. By deflecting the right wing 3 of the drone, the inner end of the right wing 3 is tilted upward to achieve the right roll of the drone. By changing the deflection angle of the right wing 3, the angular acceleration of the right roll of the drone is changed. The larger the deflection angle, the faster the right roll speed of the drone. Keep the right wing 3 in a horizontal state. By deflecting the left wing 3, the inner end of the left wing 3 is tilted upward to achieve the left roll of the drone. By changing the deflection angle of the left wing 3, the angular acceleration of the left roll of the drone is changed. The larger the deflection angle, the faster the left roll speed of the drone.

[0091] Take the example of the drone rolling to the right. Fig.11As shown, the lift of the left and right wings 3 are L and L' respectively. When the UAV is in level flight, L = L' = 1 / 2ρCSV2, ρ is the air density, C is the lift coefficient of the wing 3, S is the area of ​​the wing 3, and V is the current flight speed of the UAV. When the right wing 3 deflects by θ degrees, the lift direction of the right wing 3 also changes by θ degrees, resulting in different lifts on the left and right sides of the wing 3. The lift on the left side is greater than the lift on the right side, forming a rolling moment, causing the UAV to roll to the right, and the rolling angle acceleration is α = 1 / 2Jρ / 2V 2 [(1-cosθ)×R+sinθ×r], where J is the moment of inertia of the drone, R is the distance between the vertical component L' and the center of mass of the drone at the width of the fuselage 1, and r is the distance between the horizontal component L' and the center of mass of the drone at the height of the fuselage 1. According to actual tests, when the drone weighs 1.5 kg, has a wingspan (the distance between the outer ends of the left and right wings 3) meters, flies at a speed of 60 kilometers per hour, and flies at an altitude of 0-100 meters above sea level, the average angular velocity that can be obtained in the first 3 seconds is 480 degrees per second.

[0092] Steering: Keep the drone in a hovering state. In the hovering state, the wing 3 remains in a vertical state and its long direction is parallel to the fuselage 1. The front ends of the two wings 3 are synchronously deflected to the left to realize the left turn of the drone. The angular acceleration of the left turn of the drone is changed by changing the angle of the left deflection of the two wings 3; the front ends of the two wings 3 are synchronously rotated to the right to realize the right turn of the drone. The angular acceleration of the right turn of the drone is changed by changing the angle of the right deflection of the two wings 3. The downwash airflow generated by the rotation of the propeller 4 interacts with the wing 3 and the fuselage 1 to generate a sidewash airflow, and a sidewash airflow is generated. Fig.12 As shown, the side wash airflows on the left and right wings 3 are generally biased toward the same side, thereby causing the drone to turn.

[0093] Low-speed forward flight (flight speed 0-12 km / h): Keep the drone in a hovering state, bring the front inner sides of the two wings 3 closer together, and keep the two wings 3 mirror-distributed with the fuselage 1 to achieve low-speed forward flight of the drone. By changing the angle between the two wings 3, the flight angular acceleration of the drone is changed. Fig.13 As shown, the sidewash airflows on the left and right wings 3 are generally symmetrically distributed about the fuselage 1, and the sidewash airflow intensity on the rear side is greater, thereby generating a greater reverse thrust acting on the UAV, allowing the UAV to fly forward at a low speed.

[0094] Low-speed backward flight (flight speed 0-12 km / h): Keep the drone in a hovering state, move the rear ends of the two wings 3 inward synchronously, and keep the two wings 3 mirror-distributed with respect to the fuselage 1 to achieve low-speed backward flight of the drone. By changing the angle between the two wings 3, the flight angular acceleration of the drone is changed. Fig.14 As shown, the sidewash airflows on the left and right wings 3 are generally symmetrically distributed about the fuselage 1, and the sidewash airflow intensity on the front side is greater, thereby generating a greater reverse thrust acting on the UAV, causing the UAV to fly backwards at a low speed.

[0095] The left wing 3 refers to the wing 3 located on the left side of the UAV's flight direction; the right wing 3 refers to the wing 3 located on the right side of the UAV's flight direction. The hovering state does not mean that the UAV's flight speed is zero.

[0096] The pitch state of the UAV is changed in the level flight state: by changing the rotation of the elevator 8, when the elevator 8 rotates upward, the UAV dives downward, and vice versa, the UAV pitches upward, which is achieved by using the existing elevator control system on the UAV.

[0097] The invention has the advantages of long service life, good endurance, less prone to flight accidents and simple maintenance.

Claims

1. A tilt-rotor unmanned aerial vehicle, comprising a fuselage (1), a wing drive mechanism (10) being arranged in the fuselage (1), a rotating shaft (2) being horizontally passed through the fuselage (1) and connected to the wing drive mechanism (10), wings (3) being arranged on both sides of the fuselage (1), ends of the rotating shaft (2) being connected to the wings (3) via a rotating mechanism (50), and a propeller (4) being arranged on the rotating mechanism (50), characterized in that: The rotating mechanism (50) comprises a bracket (500), the rotating shaft (2) is connected to the propeller (4) via the bracket (500), the bracket (500) is rotatably connected to the wing (3), a spring (505) is provided between the bracket (500) and the wing (3), a rotating motor (501) is provided on the bracket (500), a first rotating rod (502) is provided at the output end of the rotating motor (501), a second rotating rod (503) is hingedly connected to the end of the first rotating rod (502), and the second rotating rod (503) is rotatably connected to the wing (3) via a first hinge seat (504); The flight control method of the UAV controls the following actions of the UAV: Lateral rolling: the drone is kept in a level flight state, in which the wings (3) are kept in a horizontal state and the long direction is perpendicular to the fuselage (1), and the lateral rolling of the drone is achieved by adjusting the vertical angle between the two wings (3); Steering: The drone is kept in a hovering state. In the hovering state, the wing (3) is kept in a vertical state and its long direction is parallel to the fuselage (1). The steering of the drone is achieved by adjusting the angle between the wing (3) and the fuselage (1); Flying forward at a low speed: keeping the UAV in a hovering state, move the front ends of the two wings (3) inwards to achieve the UAV flying forward at a low speed; Low-speed backward flight: Keep the drone in a hovering state, and move the rear ends of the two wings (3) inwards to achieve low-speed backward flight of the drone.

2. The tilt-rotor UAV according to claim 1, characterized in that: A rotating shaft (506) is provided between the bracket (500) and the wing (3); a shaft sleeve (507) is provided on the bracket (500) and is penetrated by one end of the rotating shaft (506); a second hinge seat (508) is provided on the wing (3) and is penetrated by the other end of the rotating shaft (506); and a spring (505) sleeved on the rotating shaft (506) is provided between the shaft sleeve (507) and the second hinge seat (508).

3. The tilt-rotor UAV according to claim 1, characterized in that: A rotating shaft (506) is provided between the bracket (500) and the wing (3); a shaft sleeve (507) is provided on the bracket (500) and is penetrated by the middle of the rotating shaft (506); and two second hinge seats (508) are provided on the wing (3) and are penetrated by two ends of the rotating shaft (506), respectively; a spring (505) is provided between one of the second hinge seats (508) and the shaft sleeve (507).

4. The tilt-rotor UAV according to claim 1, characterized in that: The wing drive mechanism (10) comprises a drive motor (100) fixed in a fuselage (1); a first rotating rod (101) is provided at the output end of the drive motor (100); the first rotating rod (101) is connected to a third rotating rod (103) via a second rotating rod (102) with adjustable length; and a collar (105) for connecting to a rotating shaft (2) is provided at the end of the third rotating rod (103).

5. The tilt-rotor UAV according to claim 4, characterized in that: Both ends of the second rotating rod (102) are provided with threads, the threads at both ends of the second rotating rod (102) have opposite rotation directions, and both ends of the second rotating rod (102) are threaded with screw sleeves (106), one of the screw sleeves (106) is rotatably connected to the first rotating rod (101), and the other screw sleeve (106) is rotatably connected to the third rotating rod (103).

6. The tilt-rotor UAV according to claim 5, characterized in that: One of the screw sleeves (106) is rotatably connected to the first rotating rod (101) via a first bearing (107), and the other screw sleeve (106) is rotatably connected to the third rotating rod (103) via a second bearing (108).

7. The tilt-rotor UAV according to claim 4, characterized in that: The collar (105) is provided with an opening (110), and two sides of the opening (110) extend outwards to form a first connecting portion (111) and a second connecting portion (112), respectively; the first connecting portion (111) is provided with a step hole (113), and the end of the third rotating rod (103) abuts against the bottom surface of the step hole (113), and the end of the third rotating rod (103) extends toward the second connecting portion (112) and is screwed to the second connecting portion (112).

8. The tilt-rotor UAV according to claim 4, characterized in that: The third rotating rod (103) is provided with a through slot (114), and at least two through holes (115) are provided corresponding to the through slot (114), wherein a rotating pin (116) is provided in one of the through holes (115), and the third rotating rod (103) is rotatably connected to the second rotating rod (102) via the rotating pin (116).

9. The tilt-rotor UAV according to claim 4, characterized in that: The middle portion of the second rotating rod (102) bulges outwards to form a polygonal column (109).

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