An angle-of-attack adjustable two-section wing type ornithopter

Abstract

The present application relates to the field of flapping-wing aircraft, and discloses a two-section wing flapping-wing aircraft with adjustable angle of attack during flight. The aircraft comprises a fuselage, a skeleton system connected to the fuselage, left and right wings arranged on both sides of the skeleton system and serving as flapping wings, two sets of upper and lower flapping drive systems for providing flapping power for the corresponding wings, and a front and rear swinging drive system for adjusting the angle of attack of the wings. The front and rear swinging drive system comprises a hydraulic cylinder support and a hydraulic cylinder piston rod. The hydraulic cylinder support is fixedly connected to the fuselage, and the hydraulic cylinder piston rod is hingedly connected to the skeleton system. With the extension and retraction of the hydraulic cylinder piston rod, the left and right wings connected to the skeleton system are swung, and the angle of attack of the flapping-wing aircraft is changed. During flight, the angle of attack of the aircraft wings can be adjusted, and the inner and outer wings can be curved and folded in the spanwise direction. The present application can improve the aerodynamic performance of the flapping-wing aircraft, and also improve the flexibility and endurance of the aircraft.

Description

Technical Field

[0001] This invention relates to the field of flapping-wing aircraft, and more specifically to a two-segment flapping-wing aircraft with an adjustable angle of attack during flight. Background Technology

[0002] A biomimetic flapping-wing aircraft is an aircraft that mimics the movement characteristics of flying organisms in nature. It generates lift and thrust by flapping its wings to perform various flight maneuvers in the air.

[0003] Based on the different methods of generating aerodynamic forces, existing aircraft mainly include fixed-wing aircraft, rotary-wing aircraft, and flapping-wing aircraft. Bionic flapping-wing aircraft generate lift against gravity and thrust for flight by periodically flapping their wings, effectively reducing the takeoff and landing space required for the aircraft. Furthermore, flapping-wing flight allows for rapid changes in the aircraft's attitude, enabling agile obstacle avoidance and significantly improving flight maneuverability.

[0004] Compared with traditional fixed-wing and rotary-wing aircraft, flapping-wing aircraft are quieter, more stealthy, more maneuverable, and consume less energy, and have the potential for wide application in both military and civilian fields.

[0005] Current biomimetic flapping-wing aircraft suffer from drawbacks such as low biomimicry, limited degrees of freedom, and poor payload and endurance. Summary of the Invention

[0006] To address existing problems, this invention provides a two-segment flapping-wing aircraft with adjustable angle of attack. During flight, the aircraft's wing angle of attack can be adjusted, and the inner and outer wings can be spanwise bent and folded. This invention improves the aerodynamic performance of flapping-wing aircraft while also enhancing its maneuverability and endurance.

[0007] To achieve the above objectives, the present invention provides a two-segment flapping wing aircraft with adjustable angle of attack, comprising a fuselage, a frame system connected to the fuselage, a left wing and a right wing respectively disposed on both sides of the frame system and used for flapping action, two sets of up-and-down flapping drive systems respectively providing flapping power to the corresponding sides of the wings, and a forward-and-backward swing drive system used to adjust the angle of attack of the wings.

[0008] The forward and backward swing drive system includes a hydraulic cylinder support, a hydraulic cylinder fixed to the hydraulic cylinder support, a hydraulic cylinder piston rod, a piston rod rotation shaft, and a hydraulic cylinder support rotation shaft. The hydraulic cylinder support is hinged to the fuselage via the hydraulic cylinder support rotation shaft. The hydraulic cylinder piston rod is hinged to the frame system via the piston rod rotation shaft. As the hydraulic cylinder piston rod extends and retracts, it causes the left and right wings connected to the frame system to swing, changing the angle of attack of the flapping wing aircraft.

[0009] The fuselage includes an upper fixed connector and a torso frame fixedly connected to the upper fixed connector, which together form a ring-shaped closed frame. The nose and tail are arranged opposite each other on both sides of the closed frame. The skeleton system is housed within the annular enclosure. The upper part of the skeleton system is rotatably connected to a fixed upper connector, while the lower part of the skeleton system is hinged to a forward and backward swing drive system, which is also hinged to the lower portion of the torso frame. The forward and backward swing drive system can propel the skeleton system to rotate forward and backward within a certain range around its upper rotation axis, thereby causing the left and right wings to swing and changing the angle of attack of the flapping-wing aircraft.

[0010] The skeleton system includes an upper skeleton, an upper rotating shaft that passes through the upper skeleton and connects to the upper fixed connector, a lower skeleton that is parallel to the lower part of the upper skeleton, and four skeleton fixed mounting plates. The components are fixedly connected to each other. The four skeleton fixed mounting plates are distributed along the length of the upper skeleton, and there is a gap between adjacent skeleton fixed mounting plates for installing the up-and-down flapping drive system.

[0011] The up-and-down flapping drive systems have identical structures. Each flapping drive system includes a drive motor, bearing housing A, gear shaft A, bearing housing B, gear shaft B, bearing housing C, gear A, gear B, gear C, and gear D. The output shaft of the drive motor is connected to gear C via a key, driving gear C to rotate. Gear C meshes with gear A. Gear A and gear B are coaxial and are fixedly connected to gear shaft A via a key, driving gear shaft A to rotate around bearing housing A. Gear B meshes with gear D, and gear D is fixedly connected to gear shaft B via a key, driving gear shaft B to rotate around bearing housing B. Gear shaft B is fixedly connected to the wing on the corresponding side. The rotation of the drive motor, through the transmission of each stage of gears, drives the wing on the corresponding side to achieve up-and-down flapping motion.

[0012] The left and right wings have the same structure, each including a wing rotation shaft, an outer wing frame, an inner wing frame, an inner wing support rod, an inner and outer wing connecting shaft, four inner wing ribs, four outer wing ribs, a crank, and a rocker arm; the gear shaft B of the up-and-down flapping drive system drives the crank to rotate, and the crank in turn drives the rocker arm to swing; the rocker arm is hinged to the inner wing frame and the inner wing support rod respectively, and the inner wing frame and the inner wing support rod are hinged to the outer wing frame through the inner and outer wing connecting shaft; the inner wing ribs and the outer wing ribs are fixed to the inner wing frame and the outer wing frame respectively.

[0013] It also includes a control module, which is connected to the up-and-down flapping drive system and the forward-and-backward swinging drive system via signal connection; according to the requirements, it issues corresponding commands to control the rotation of the drive motor of the up-and-down flapping drive system and to control the movement of the hydraulic cylinder piston rod of the forward-and-backward swinging drive system.

[0014] The outer wing frame, inner wing frame, inner wing support rod, inner wing rib, and outer wing rib of the left and right wings are all made of carbon fiber, which helps to reduce the overall weight of the fuselage.

[0015] The surfaces of each gear in the up-and-down pounce drive system are provided with holes for weight reduction.

[0016] Compared with the prior art, the two-segment flapping-wing aircraft with adjustable angle of attack provided by the present invention has the following beneficial effects: During flight, two sets of up-and-down flapping drive systems control the up-and-down movement of the left and right wings. Through the crank-rocker mechanism, the four-bar linkage consisting of the inner and outer wing frames deforms, realizing the spanwise folding of the inner and outer wings. When the wings flap downward, they maintain a large wingspan as much as possible, and when they flap upward, the wingspan folds, which improves the aerodynamic performance of the flapping-wing aircraft. During flight, the forward and backward swing drive system controls the extension and retraction of the hydraulic cylinder piston rod to drive the frame system to move forward and backward, thereby causing changes in the angle of attack of the left and right wings and altering the lift and drag coefficients of the flapping-wing aircraft. In different flight environments, selecting the appropriate wing angle of attack can improve the flexibility and increase the safety of the flapping-wing aircraft. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the flapping-wing aircraft provided by the present invention; Figure 2 This is a side view of the overall structure of the flapping-wing aircraft wing at the positive angle of attack provided by the present invention; Figure 3 This is a side view of the overall structure of the flapping-wing aircraft wing at a negative angle of attack, provided by the present invention. Figure 4 This is a top view of the overall structure of the flapping-wing aircraft provided by the present invention; Figure 5 This is a front view of the flapping-wing aircraft provided by the present invention when both wings are fully deployed; Figure 6 This is a front view of the flapping-wing aircraft provided by the present invention when the wings on both sides are bent in the spanwise direction; Figure 7 This is a schematic diagram of the fuselage of the flapping-wing aircraft provided by the present invention; Figure 8 This is a partial schematic diagram of the frame system and the up-and-down flapping drive system of the flapping-wing aircraft provided by the present invention; Figure 9 This is a top view of the left wing of the flapping-wing aircraft provided by the present invention; Figure 10 This is a front view of the left wing of the flapping-wing aircraft provided by the present invention; Figure 11This is a side view of the flapping drive system of the flapping-wing aircraft provided by the present invention; Figure 12 This is a partial schematic diagram of the forward and backward oscillation drive system and fuselage of the flapping-wing aircraft provided by the present invention.

[0018] Figure label: 1. Fuselage; 101. Upper fixed connector; 102. Torso frame; 103. Nose; 104. Tail; 2. Skeleton system; 201. Upper skeleton; 202. Upper rotating shaft; 203. Lower skeleton; 204. Fixed mounting plate; 3. Left wing; 301. Wing rotating shaft; 302. Left outer wing frame; 303. Left inner wing frame; 304. Left inner wing support rod; 305. Inner and outer wing connecting shaft; 306. Inner wing rib; 307. Outer wing rib; 308. Crank; 309 4. Right wing; 5. Up-and-down flapping drive system; 501. Drive motor; 502. Bearing housing A; 503. Gear shaft A; 504. Bearing housing B; 505. Gear shaft B; 506. Bearing housing C; 507. Gear A; 508. Gear B; 509. Gear C; 510. Gear D; 6. Forward and backward swinging drive system; 601. Hydraulic cylinder support; 602. Hydraulic cylinder; 603. Hydraulic cylinder piston rod; 604. Piston rod rotating shaft; 605. Hydraulic cylinder support rotating shaft. Detailed Implementation

[0019] To more clearly illustrate the technical solutions of this invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various modifications or alterations to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention.

[0021] like Figures 1 to 12 As shown, the present invention provides a two-segment flapping wing aircraft with adjustable angle of attack, including a fuselage 1, a frame system 2 for fixed connection, a left wing 3 and a right wing 4 respectively arranged on both sides of the frame system 2 and for flapping action, two sets of up-and-down flapping drive systems 5 respectively providing flapping power to the corresponding sides of the wings, and a forward-and-backward swing drive system 6 for adjusting the angle of attack of the wings. The fuselage 1 includes an upper fixed connector 101 and a torso frame 102 fixedly connected to the upper fixed connector 101, which together form an annular closed frame. The nose 103 and tail 104 are arranged opposite each other on both sides of the closed frame. The skeleton system 2 is arranged inside the annular closed frame. The upper part of the skeleton system 2 is rotatably connected to the upper fixed connector 101. The lower part of the skeleton system 2 is hinged to a forward and backward swing drive system 6, which is hinged to the lower part of the torso frame 102. Preferably, the upper fixed connector 101 is connected to the frame system 2 via the upper frame 201 and the upper rotating shaft 202. The hydraulic cylinder support 601 of the forward and backward swing drive system 6 is hinged to the lower part of the torso frame 102. The hydraulic cylinder piston rod 603 of the forward and backward swing drive system 6 is hinged to the frame system 2. The extension and retraction movement of the hydraulic cylinder piston rod 603 pushes the frame system 2 to rotate forward and backward around the upper rotating shaft 202 within a certain range, thereby driving the left wing 3 and right wing 4 connected to the frame system 2 to swing, changing the angle of attack of the flapping wing aircraft. like Figure 8 As shown, the skeleton system 2 includes an upper skeleton 201, an upper rotating shaft 202 that passes through the upper skeleton 201 and connects to the upper fixed connector 101, a lower skeleton 203 arranged parallel to the lower part of the upper skeleton 201, and four skeleton fixing mounting plates 204. All components are fixedly connected by screws. The four skeleton fixing mounting plates 204 are distributed along the length of the upper skeleton 201, with gaps between adjacent plates. These gaps are used to install the up-and-down pounce drive system 5. The lower skeleton 203 is connected to the hydraulic cylinder piston rod 603. The frame system 2 is hinged to the piston rod rotating shaft 604, and the movement of the frame system 2 is driven by the forward and backward extension of the piston rod 603 of the hydraulic cylinder; the frame fixing plate 204 is connected to two sets of symmetrically arranged up and down flapping drive systems 5 through motor 501, bearing seat A502, gear shaft A503, bearing seat B504 and gear shaft B505, and is connected to the wing rotating shaft 301 of the frame system 5 through the bearing seat C506 connected to it, and to the left wing 3 and the right wing 4 respectively; the front and rear drive motors 501 are fixedly connected to the two middle frame fixing plates 204 with screws; The left wing 3 and the right wing 4 have the same structure and are symmetrically distributed. Taking the left wing 3 as an example, it includes a wing rotation shaft 301, a left outer wing frame 302, a left inner wing frame 303, a left inner wing support rod 304, an inner and outer wing connecting shaft 305, four inner wing ribs 306, four outer wing ribs 307, a crank 308, and a rocker arm 309. The left wing 3 flaps up and down around its wing rotation shaft 301 under the drive of the up-and-down flapping drive system 5. The gear shaft B505 of the 5 drives the crank 308 to rotate, and the crank 308 in turn drives the rocker arm 309 to swing. The rocker arm 309 is hinged to the left inner wing frame 303 and the left inner wing support rod 304 respectively. The left inner wing frame 303 and the left inner wing support rod 304 are also hinged to the left outer wing frame 302 through the inner and outer wing connecting shaft 305. There are four inner wing ribs 306 and four outer wing ribs 307, which are glued to the left inner wing frame 303 and the left outer wing frame 302 respectively. The two up-and-down flapping drive systems 5 are identical in structure and symmetrically distributed front and rear. Taking the left wing flapping drive system 5 as an example, it mainly includes a drive motor 501, bearing housing A502, gear shaft A503, bearing housing B504, gear shaft B505, bearing housing C506, gear A507, gear B508, gear C509, and gear D510. The motor output shaft of the drive motor 501 is connected to gear C509 by a key, driving gear C509 to rotate. Gear C509 meshes with gear A507. Gear A507 and gear B508 are coaxial. The gear is fixedly connected to the gear shaft A503 via a key, causing the gear shaft A503 to rotate around the bearing seat A502; gear B508 meshes with gear D510, and gear D510 is fixedly connected to the gear shaft B505 via a key, causing the gear shaft B505 to rotate around the bearing seat B504; gear shaft B505 is fixedly connected to the crank 308 of the left wing 3, and the rotation of the drive motor 501 is transmitted through the gears of each stage, ultimately driving the crank 308 to rotate, thereby driving the left wing 3 to achieve the up-and-down flapping motion; the holes on the gears of each stage of the up-and-down flapping drive system 5 are mainly for the purpose of weight reduction; The aforementioned forward and backward swinging drive system 6 includes a hydraulic cylinder support 601, a hydraulic cylinder 602, a hydraulic cylinder piston rod 603, a piston rod rotation shaft 604, and a hydraulic cylinder support rotation shaft 605. The bottom of the hydraulic cylinder 602 is fixedly mounted on the hydraulic cylinder support 601, and the hydraulic cylinder support 601 is hinged to the torso frame 102 of the fuselage 1 via the hydraulic cylinder support rotation shaft 605. The hydraulic cylinder piston rod 603 is hinged to the lower frame 203 of the frame system 2 via the piston rod rotation shaft 604. The forward and backward extension and retraction of the hydraulic cylinder piston rod 603 drives the frame system 2 to swing forward and backward, thereby changing the angle of attack of the flapping-wing aircraft.

[0022] The present invention also includes a control module, which is signal-connected to the up-and-down flapping drive system 5 and the forward-and-backward swinging drive system 6; according to the requirements, it issues corresponding commands to control the rotation of the drive motor 501 of the up-and-down flapping drive system 5 and to control the movement of the hydraulic cylinder piston rod 603 of the forward-and-backward swinging drive system 6.

[0023] The left outer wing frame 302, left inner wing frame 303, left inner wing support rod 304, inner wing rib 306 and outer wing rib 307 of the left wing 3 are all made of carbon fiber, which helps to reduce the overall weight of the fuselage; the same parts of the right wing 4 and the left wing 3 are also made of carbon fiber.

[0024] The outer skin of the left and right wings is made of umbrella fabric or polyester film material and is bonded and fixed to the wing ribs with adhesive.

[0025] The working principle of the two-segment flapping-wing aircraft with adjustable angle of attack provided by the present invention is described below: When an ornithopter moves in the air, it generates lift and thrust by flapping its wings up and down, which in turn causes folding motion in the spanwise direction and twisting motion in the chordwise direction. Aerodynamic calculations show that the downward flapping of the wings provides the majority of the lift and thrust during flight. Therefore, to obtain the maximum aerodynamic force, the wing area and wingspan should be kept as large as possible during this phase. Taking the left wing 3 as an example, when the ornithopter's wing flaps downward, the up-and-down flapping drive system 5 drives the crank 308 to rotate via the gear shaft B505, which in turn drives the rocker arm 309 to swing. This causes the parallelogram structure formed by the rocker arm 309, the left inner wing frame 303, the left inner wing support rod 304, and the left outer wing frame 302 to compress inward. The inner and outer wings remain fully extended for a longer period of time, increasing the wing area during downward flapping and thus increasing the lift and thrust of the ornithopter.

[0026] During the upward flapping of the flapping wing of an ornithopter, it primarily provides a small portion of thrust and negative lift during flight. Therefore, to minimize the impact of negative lift on the ornithopter, the inner and outer wings should be relatively folded in the spanwise direction during this phase, maintaining a sufficiently large spanwise fold angle and a sufficiently small wing area. Taking the left wing 3 as an example, when the ornithopter's wing flaps upward, the up-and-down flapping drive system 5 drives the crank 308 to rotate via the gear shaft B505, which in turn drives the rocker arm 309 to swing. This causes the parallelogram structure formed by the rocker arm 309, the left inner wing frame 303, the left inner wing support rod 304, and the left outer wing frame 302 to extend outward. The inner and outer wings remain relatively folded for a relatively long time, reducing the wing area during upward flapping and thus reducing the impact of negative lift on the ornithopter.

[0027] The angle of attack of a flapping-wing aircraft directly affects its aerodynamic force. Within a certain range, the lift coefficient increases with the angle of attack. When the angle of attack exceeds the critical angle of attack, the lift of the wing decreases rapidly, and the drag increases rapidly, causing the flapping-wing aircraft to stall. Maintaining a suitable angle of attack within the allowable range of different flight environments can increase the lift coefficient of the flapping-wing aircraft and obtain the maximum aerodynamic force. One end of the forward and backward oscillation drive system 6 is hinged to the body frame 102 of the fuselage 1 via a hydraulic cylinder support rotating shaft 605, and the other end is hinged to the lower frame 203 of the frame system 2 via a piston rod rotating shaft 604. During the flight of the flapping-wing aircraft, the forward and backward extension of the hydraulic cylinder piston rod 603 drives the forward and backward oscillation of the frame system 2. The left wing 3 and the right wing 4 are mounted on the frame system 2, so the forward and backward movement of the hydraulic cylinder piston rod 603 indirectly changes the angle of attack of the wings, thereby improving the aerodynamic performance and maneuverability of the flapping-wing aircraft.

[0028] The flapping-wing aircraft design provided by this invention has a simple structure and is easy to operate and control, with a high degree of biomimicry in both its motion and appearance. This invention improves the aerodynamic performance, flexibility, and endurance of the flapping-wing aircraft by achieving spanwise folding of the inner and outer wings and adjustment of the wing angle of attack.

[0029] above Figures 1 to 12 The two-segment flapping-wing aircraft with adjustable angle of attack shown is a specific embodiment of the present invention, which has demonstrated the substantial features and progress of the present invention. Based on the actual needs of use, equivalent modifications in shape, structure, etc., can be made to it according to the inspiration of the present invention, and all such modifications are within the scope of protection of the present invention.

Claims

1. A two-segment flapping-wing aircraft with adjustable angle of attack, characterized in that: It includes the fuselage, the frame system connected to the fuselage, the left and right wings respectively set on both sides of the frame system and used for flapping, two sets of up-and-down flapping drive systems that provide flapping power to the wings on the corresponding sides, and the forward and backward swaying drive system that adjusts the wing angle of attack. The forward and backward swing drive system includes a hydraulic cylinder support, a hydraulic cylinder fixed to the hydraulic cylinder support, a hydraulic cylinder piston rod, a piston rod rotation shaft, and a hydraulic cylinder support rotation shaft; the hydraulic cylinder support is hinged to the fuselage via the hydraulic cylinder support rotation shaft; the hydraulic cylinder piston rod is hinged to the frame system via the piston rod rotation shaft; as the hydraulic cylinder piston rod extends and retracts, it drives the left and right wings connected to the frame system to swing, changing the angle of attack of the flapping wing aircraft; The left and right wings have the same structure, both including a wing rotation shaft, an outer wing frame, an inner wing frame, an inner wing support rod, an inner and outer wing connecting shaft, four inner wing ribs, four outer wing ribs, a crank, and a rocker arm; The up-and-down flapping drive systems have the same structure. Each flapping drive system includes a drive motor, bearing housing A, gear shaft A, bearing housing B, gear shaft B, bearing housing C, gear A, gear B, gear C and gear D. The output shaft of the drive motor is connected to gear C via a key, driving gear C to rotate. Gear C meshes with gear A. Gear A and gear B are coaxial and are fixedly connected to gear shaft A via a key, driving gear shaft A to rotate around bearing seat A. Gear B meshes with gear D, and gear D is fixedly connected to gear shaft B via a key, driving gear shaft B to rotate around bearing seat B. Gear shaft B is fixedly connected to the wing on the corresponding side. The rotation of the drive motor, through the transmission of gears at each stage, drives the wing on the corresponding side to achieve an up-and-down flapping motion. The gear shaft B of the up-and-down flapping drive system drives the crank to rotate, and the crank in turn drives the rocker arm to swing; the rocker arm is hinged to the inner wing frame and the inner wing support rod respectively, and the inner wing frame and the inner wing support rod are hinged to the outer wing frame through the inner and outer wing connecting shaft; the inner wing rib and the outer wing rib are fixed to the inner wing frame and the outer wing frame respectively.

2. The two-segment flapping-wing aircraft with adjustable angle of attack as described in claim 1, characterized in that: The fuselage includes an upper fixed connector and a torso frame fixedly connected to the upper fixed connector, which together form a ring-shaped closed frame. The nose and tail are arranged opposite each other on both sides of the closed frame. The skeleton system is set inside the ring of the annular closed frame. The upper part of the skeleton system is rotatably connected to the upper fixed connector, and the lower part of the skeleton system is hinged to the front and back swing drive system. The front and back swing drive system is hinged to the lower part of the torso frame.

3. The two-segment flapping-wing aircraft with adjustable angle of attack as described in claim 2, characterized in that: The skeleton system includes an upper skeleton, an upper rotating shaft that passes through the upper skeleton and is connected to the upper fixed connector, a lower skeleton that is parallel to the lower part of the upper skeleton, and four skeleton fixed mounting plates, with each component fixedly connected to the other. Four frame mounting plates are distributed along the length of the upper frame, and there is a gap between adjacent frame mounting plates for installing the up-and-down flapping drive system.

4. The two-segment flapping-wing aircraft with adjustable angle of attack as described in claim 1, characterized in that: It also includes a control module, which is connected to the up-and-down flapping drive system and the forward-and-backward swinging drive system via signal connection; according to the requirements, it issues corresponding commands to control the rotation of the drive motor of the up-and-down flapping drive system and to control the movement of the hydraulic cylinder piston rod of the forward-and-backward swinging drive system.

5. The two-segment flapping-wing aircraft with adjustable angle of attack as described in claim 1, characterized in that: The outer wing frame, inner wing frame, inner wing support rod, inner wing rib, and outer wing rib of the left and right wings are all made of carbon fiber.

6. The two-segment flapping-wing aircraft with adjustable angle of attack as described in claim 1, characterized in that: The surfaces of each gear in the up-and-down pounce drive system are provided with holes for weight reduction.

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