Multi-degree-of-freedom flapping wing glider with aerodynamic configuration

Abstract

The utility model discloses a multi-degree-of-freedom flapping-wing glider with an aerodynamic shape. The multi-degree-of-freedom flapping-wing glider comprises a bilaterally symmetrical fuselage assembly, a flapping-wing assembly and an empennage assembly capable of being quickly replaced. The fuselage assembly comprises a frame unit and two flapping wing adjusting units, each flapping wing assembly comprises a flapping wing frame, a composite turbulent flow structure and a turbulent flow plate, and the empennage assembly is of a triangular, trapezoidal or V-shaped structure and is connected with the frame unit through an empennage connecting piece. A streamline shell is arranged at the front end of the frame unit, two pitch angle adjusting motors are arranged in the middle, and an empennage steering engine is arranged at the tail. The flapping wing frame is of a structure with a thick front part and a thin tail part and is coated with a film wing; the wing tip of the flapping wing frame is provided with a composite spoiler structure, and the front part is provided with a strip-shaped spoiler, so that trailing vortex is effectively inhibited, airflow separation is delayed, and the lift-drag ratio is increased. The glider has the advantages of high aerodynamic efficiency, excellent structural strength, multi-degree-of-freedom accurate control and batch production consistency.

Description

Technical Field

[0001] This utility model relates to the field of flapping-wing aircraft technology, and in particular to a multi-degree-of-freedom flapping-wing glider with an aerodynamic shape. Background Technology

[0002] Ornithoptering aircraft are flight devices that mimic the lift and thrust generated by birds and insects through wing flapping. They possess natural advantages in terms of high maneuverability, low-speed hovering ability, and environmental adaptability. With the development of micro unmanned aerial vehicles (MAVs) and autonomous flight platforms, ornithoptering aircraft show broad prospects in applications such as military reconnaissance, nature observation, search and rescue missions, and biomimetic research.

[0003] However, compared with fixed-wing or multi-rotor systems, flapping-wing aircraft generally suffer from insufficient degrees of freedom in control, low airfoil aerodynamic efficiency, complex structure, poor manufacturing consistency, and poor attitude stability, which have become key technological bottlenecks restricting their further development. Current research focuses on: improving the degrees of freedom and decoupled control capabilities of flapping-wing systems, optimizing aerodynamic shapes to improve lift-to-drag ratio, enhancing structural lightweighting and rigidity, and improving manufacturing processes to meet the needs of mass production.

[0004] Currently, the design schemes for flapping-wing aircraft mainly revolve around the following aspects:

[0005] Airfoil design: Traditional flapping-wing aircraft mostly adopt simple airfoil designs, often using rectangular or trapezoidal airfoils. Although these airfoils can meet basic aerodynamic requirements, there is still room for improvement in terms of increasing lift and reducing air resistance.

[0006] Drive system: Most existing flapping-wing aircraft use a single motor and linkage mechanism for drive. This solution has a simple structure, but its control flexibility and symmetry are poor, making it difficult to meet the needs of complex flight maneuvers.

[0007] Materials and Manufacturing Process: Most flapping-wing aircraft are manufactured using manual cutting and assembly methods, employing conventional polyester films (such as PET film) as the wing surface material. This manufacturing method is acceptable for small aircraft, but it presents problems for large platforms or scenarios requiring high precision.

[0008] As shown in the prior art application document CN217320745U, the design of the flapping-wing aircraft includes a flapping-wing frame, a set of flapping-wing rockers, a flapping-wing actuator, and a crank assembly. The crank assembly consists of a crank section, a connecting rod section, and a ball joint. The ball joint connects the crank section and the connecting rod section. This design reduces mechanical wear on the flapping-wing mechanism, avoids hardware interference between the connecting rod and the rocker, and improves system stability. However, this design has limitations. When the crank section and the connecting rod are connected via the ball joint, the angular uncertainty may affect the stability and accuracy of the rocker base rotation, especially in flight missions with high precision control requirements, where control accuracy may be limited.

[0009] Another related technical solution, as shown in patent CN115230960A, uses a differential control method to adjust the angle of attack difference between the outer sections of the two sides of the flapping-wing aircraft to achieve precise roll control. This solution improves the aircraft's steering flexibility and adapts to maneuver requirements under different flight conditions. However, this method requires a more complex control system and may suffer from circuit response lag during high-frequency operation, affecting the real-time stability of the flight.

[0010] Another example is the technical solution CN108674651B, which proposes to transmit power through a crank assembly and connecting rod structure, optimizing the drive system of ornithopter aircraft. This solution reduces hardware interference and improves stability through ball joints, making it suitable for scenarios requiring high control precision. Nevertheless, it still faces challenges such as high system complexity, increased weight, and insufficient control flexibility, and may not meet the requirements, especially for larger or higher-load aircraft.

[0011] Patent CN110550206B proposes a flapping-wing aircraft based on dual-motor independent drive, achieving enhanced attitude control by controlling the flapping frequency and phase difference of the left and right wings. This design significantly improves the aircraft's maneuverability and flight stability, making it particularly suitable for applications in complex environments. However, the complexity of this solution in terms of transmission mechanism and motor control leads to higher costs and lower manufacturing efficiency.

[0012] Furthermore, CN110550207B proposes a design that introduces multi-degree-of-freedom control into an ornithopter, further improving the aerodynamic performance of the ornithopter by optimizing the airfoil and drive structure. However, the multi-degree-of-freedom structural design brings higher system complexity and weight issues, and has not yet achieved ideal results in terms of high-precision control and energy efficiency.

[0013] In summary, while existing designs have achieved breakthroughs in certain aspects, such as improved stability, control precision, and flight maneuverability, they still suffer from problems such as complex control, low transmission efficiency, large structural weight, and high manufacturing costs. Therefore, optimizing the drive system of flapping-wing aircraft, reducing weight, improving manufacturing precision, and simultaneously ensuring high flight stability and maneuverability remain pressing technical challenges in this field.

[0014] The significant shortcomings of existing technologies in terms of structural simplification, control decoupling, aerodynamic optimization, and manufacturing consistency include:

[0015] 1. Complex structure and low degree of freedom of control: Most adopt a linkage transmission structure, which leads to the coupling of the joint motions. It is difficult to control the left and right wings independently, which is not conducive to performing complex maneuvering flight actions and affects the integration of embodied intelligent control technology.

[0016] 2. Simple airfoil design, poor aerodynamic performance: Traditional designs use straight or simple airfoils, which make it difficult to optimize lift and drag in gliding and flapping modes, affecting flight efficiency and stability.

[0017] 3. Poor manufacturing precision and low repeatability: The wing surface material is mostly KT board or hand-cut film, which makes it difficult to standardize the wing shape and affects the consistency of mass production and assembly.

[0018] 4. Insufficient flight structure stability and poor vibration resistance: Due to the lack of reasonable stiffness layout and modal control, some structures experience resonance interference during flapping, affecting attitude maintenance accuracy. Utility Model Content

[0019] The purpose of this invention is to overcome the shortcomings of the existing technology and address the technical deficiencies of existing flapping-wing aircraft in terms of structural design, aerodynamic performance, control methods, material processing, and manufacturing consistency. It aims to provide a multi-degree-of-freedom flapping-wing glider with an aerodynamic shape, and to solve the following key technical problems:

[0020] 1. Inefficient flapping wing airfoil design and low aerodynamic efficiency: Traditional flapping wing aircraft often use simple rectangular or trapezoidal airfoils, making it difficult to simultaneously achieve lift and stability in gliding and flapping modes. This invention improves lift output and lift-to-drag ratio, and enhances flight efficiency by introducing an aerodynamically optimized airfoil and a compound terminal spoiler structure.

[0021] 2. Traditional connecting rod / crank transmission methods suffer from low degrees of freedom and severe coupling: Existing flapping wing mechanisms mostly rely on connecting rod transmissions, which suffer from problems such as complex structure, long transmission paths, coupling of left and right wing movements, and difficulty in intelligent control. This utility model adopts a left-right symmetrical multi-degree-of-freedom motor series drive method, reducing structural complexity and realizing independent control of roll (flapping) and pitch, thus meeting the requirements of high-maneuverability intelligent control.

[0022] 3. Poor precision in wing materials and manufacturing processes, resulting in low manufacturing consistency: Existing products mainly use materials such as KT board to manually manufacture membrane wings, which are prone to uncontrolled deformation and have poor repeatability. This invention uses PET film laser cutting and thermal tensioning processes, combined with carbon fiber frame units, resulting in high manufacturing precision, strong performance consistency, and ease of mass production.

[0023] 4. Insufficient structural stability and vibration resistance: Existing aircraft are prone to periodic resonance during wing flapping, leading to decreased attitude control accuracy. This invention improves flight stability by optimizing fuselage layout and rigidity design, increasing modal frequencies, avoiding structural resonance interference.

[0024] The objective of this utility model is achieved through the following technical solution:

[0025] A multi-degree-of-freedom flapping-wing glider with an aerodynamic shape, which is symmetrical in shape, includes a fuselage assembly, two flapping-wing assemblies and a tail assembly;

[0026] The fuselage components include:

[0027] A frame unit is formed by connecting a first side plate and a second side plate through several connectors. The front end of the frame unit is provided with an aerodynamic shell. The middle part of the frame unit is provided with a motor compartment, and the motor compartment is provided with two pitch angle adjustment motors. The rear end of the frame unit is equipped with a tail fin servo, and the tail fin servo is connected to a tail fin connector. A battery is also installed inside the frame unit.

[0028] Two flapping wing adjustment units are respectively installed on both sides of the frame unit. Each flapping wing adjustment unit includes a pitch adjustment rod with a U-shaped structure, a roll motor, and a rotating rod. The pitch adjustment rod is connected to the output shaft of the pitch angle adjustment motor. The roll motor is installed at the front end of the pitch adjustment rod. The output shaft of the roll motor is connected to one end of the rotating rod through a coupling. The other end of the rotating rod is fixed to the end of the pitch adjustment rod through a coupling. A flapping wing connector is installed on the rotating rod.

[0029] Each of the flapping wing assemblies includes:

[0030] The flapping wing frame has its starting end in the outward direction connected to the flapping wing connector. The flapping wing frame has an overall frame structure that is thick at the front and thin at the rear, and is covered with a wing membrane by thermal tensioning.

[0031] The composite turbulence structure is formed by an integral fixed connection of a fixed frame and three guide vanes. The fixed frame is installed at the end of the flapping wing frame in the outward direction. The area of ​​the three guide vanes decreases from front to back and the angle of their tilt decreases at equal angles.

[0032] The spoiler is strip-shaped and is located at the front of the flapping wing frame at a distance of 0.6 to 0.7 times the length of the flapping wing frame. The spoiler forms an angle with the flapping wing frame and is inclined towards the direction of the composite spoiler structure.

[0033] The tail fin assembly has a triangular, trapezoidal, or V-shaped structure and is connected to the frame unit via the tail fin connector.

[0034] Furthermore, the tilt angle of the guide vane ranges from 10° to 50°, the length of a single guide vane accounts for 5% to 10% of the total length of a single flapping wing frame, and the lengths of each guide vane are not equal. The width of a single guide vane is 25% to 35% of its own length.

[0035] Furthermore, the tail portions of the first side plate and the second side plate are fixed to each other by a tail plate, which is provided with mounting holes. The tail fin servo is embedded in the mounting holes and secured by fasteners.

[0036] Furthermore, the first side plate, the second side plate, and the connecting rod are all made of carbon fiber sheet material and are laser-cut and processed. The pitch adjustment rod is integrally formed by sheet metal bending. The rotating rod and each rod in each flapping wing frame are made of carbon fiber tube cutting and drilling. Several through holes are provided on the first side plate and the second side plate, and several channels are provided between the first side plate and the second side plate to facilitate wiring, heat dissipation, and subsequent connection of other task modules.

[0037] Furthermore, a control unit connected to the battery is provided in the channel via the connector. The control unit is equipped with a wireless transmission module and is connected to the pitch angle adjustment motor, the tail fin servo, and the roll motor.

[0038] Furthermore, the flapping wing connector includes a rotating rod connecting end and a flapping wing connecting end. The rotating rod connecting end includes three segments of sleeve claws that fit onto the rotating rod. The sleeve claws at both ends are fixed to the rotating rod by fasteners. The flapping wing connecting end is provided with a support frame that matches the side shape of the flapping wing frame and is wider at the front and narrower at the back. Several ribs are provided at equal intervals in the support frame to increase strength and prevent the flapping wing frame from laterally entering the air.

[0039] Furthermore, a support rod is provided at the front of the flapping wing frame along the outward direction, and several reinforcing ribs are sleeved on the support rod to improve bending stiffness and torsional performance and avoid stress concentration on one side. The first-order modal frequency of the flapping wing frame is higher than the flapping frequency of the flapping wing assembly.

[0040] Furthermore, one end of the tail fin connector is connected to the tail fin servo output shaft via a rudder disc, and the other end is connected to the tail fin assembly via a combination of bolts and pins, enabling quick replacement of different types of tail fin assemblies; the tail fin assembly is an isosceles triangular tail fin.

[0041] Furthermore, the length of the spoiler is within 10% to 15% of the length of the front end of the corresponding flapping wing frame, and the tilt angle is 15 to 25°.

[0042] Furthermore, the wing film is any one of PET film, PVDF film or composite PI film, and the basic shape is obtained by laser cutting. Then, the outer edge of the film is glued to the flapping wing frame. Finally, the wrinkled area in the middle of the film wing is heated by a hot air gun to achieve self-tensioning.

[0043] Compared with the prior art, the beneficial effects of the technical solution of this utility model are:

[0044] 1. The front of the fuselage is equipped with a simulated streamlined aerodynamic shell; this solves the problems of poor airframe drag and low gliding efficiency in traditional flapping-wing aircraft; it reduces airframe drag, improves the lift-to-drag ratio during flight and gliding, and enhances gliding endurance and stability.

[0045] 2. Two pitch angle adjustment motors and roll motors are symmetrically arranged on the left and right sides to achieve decoupled control of pitch and roll; this solves the problems of low degree of freedom, coupled left and right wing motion, and poor maneuverability of existing linkage or single motor drive structures; it enables independent adjustment of pitch and flapping, greatly improving maneuverability and complex attitude control capabilities.

[0046] 3. The flapping wing frame has a thick front and thin rear structure, covered with PET / PVDF / PI film, and can be equipped with an adjustable tensioning structure at the rear; it solves the problems of wrinkles, loosening or oscillation that are prone to occur in traditional membrane wings, resulting in discontinuous lift; through thermal shrinkage or mechanical tensioning, it ensures that the wing membrane is always flat, so as to achieve continuous lift output and flight stability.

[0047] 4. The flapping wing frame is equipped with a composite spoiler structure at the wingtip, which is connected by a fixed frame to three guide vanes of decreasing size and tilt angle. This solves the problem of concentrated tail vortex at the wingtip, which interferes with attitude stability during maneuvers. It disperses tail vortex, delays airflow separation, suppresses tail vortex interference, and improves the linear consistency of flapping lift and lateral stability.

[0048] 5. Install strip-shaped spoilers at a distance of 0.6 to 0.7 times from the starting end of the single flapping wing frame outward in the direction of the wingtip, with an upward tilt of 15° to 25°; solve the problems of easy airflow separation and low lift efficiency in the downward phase during the flapping cycle; form an auxiliary lift zone by locally disturbing the airflow, improve the asymmetric aerodynamic response, and increase the aerodynamic efficiency per unit stroke.

[0049] 6. The side panels, pitch adjustment rods, connecting rods, etc. of the fuselage frame unit are all made of carbon fiber sheets and laser-cut; this solves the problems of poor consistency, insufficient structural strength and precision caused by manual or KT board manufacturing; it achieves a lightweight and high-strength structure with high dimensional accuracy, enhances overall rigidity and repeatability, and facilitates mass production.

[0050] 7. By increasing the thickness of the plates and rationally distributing the reinforcing ribs, the first-order modal frequency of the fuselage components is made higher than the 5 Hz flapping frequency; the problem of structural resonance interfering with flight and attitude instability is solved; resonance is avoided, and flight stability and control accuracy are improved.

[0051] 8. The tail assembly can be triangular, trapezoidal, or V-shaped, and can be quickly replaced via a rudder disc and pin / magnetic connection structure; this solves the problems of cumbersome tail replacement or maintenance and difficulty in adapting to different missions; by quickly replacing different tail shapes, maintainability and adaptability are improved, and the flight envelope is extended.

[0052] 9. The flapping wing connector has multiple equally spaced ribs that are fastened to the rotating rod claws; this solves problems such as lateral air intake or stress concentration in the wing frame that cause structural deformation; it enhances the strength of the connector, prevents lateral air intake and stress concentration, and ensures flight reliability.

[0053] 10. Based on the synergistic effect of the composite spoiler structure and the front spoiler, it not only suppresses the wake vortex, but also balances the lift distribution in each stage of the flapping cycle, further improving the lift-to-drag ratio. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the overall structure of the multi-degree-of-freedom flapping glider of this utility model.

[0055] Figure 2 This is a structural diagram of the fuselage components.

[0056] Figure 3 This is a schematic diagram of a single flapping wing assembly.

[0057] Figure 4 This is an enlarged schematic diagram of the composite turbulence structure in the flapping wing assembly.

[0058] Figure 5 A schematic diagram of the tail fin assembly.

[0059] Reference numerals: 1-Fuselage assembly, 2-Flapping wing assembly, 3-Tail wing assembly, 101-First side plate, 102-Second side plate, 103-Connector, 104-Aerodynamic shell, 105-Motor compartment, 106-Battery, 107-Tail wing servo, 108-Tail wing connector, 109-Pitch adjustment rod, 110-Roll motor, 111-Rotator, 112-Flapping wing connector, 1121-Claw, 1122-Support frame, 1123-Rib plate, 113-Tail plate, 201-Flapping wing frame, 202-Wing membrane, 203-Composite spoiler structure, 2031-Fixed frame, 2032-Guide vane, 2033-Guide vane, 2034-Guide vane, 204-Spoiler. Detailed Implementation

[0060] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0061] Example 1

[0062] This embodiment provides a multi-degree-of-freedom flapping-wing glider with an aerodynamic shape. The glider is symmetrically designed and employs a lightweight, high-strength frame structure, providing rigid support and aerodynamic symmetry during flight. Specifically, it includes a fuselage assembly 1, two flapping-wing assemblies 2, and a tail assembly 3. (See attached image.) Figure 1 Specifically:

[0063] I. See Figure 2 The fuselage assembly 1 includes a frame unit and two flapping wing adjustment units;

[0064] (1) The frame unit is composed of a first side plate 101 and a second side plate 102 connected by multiple connectors 103. The front end of the frame unit is provided with an aerodynamic housing 104. The middle part of the frame unit is provided with a motor compartment 105. Two pitch angle adjustment motors are symmetrically installed in the motor compartment 105 to realize the pitch angle adjustment of the flapping wing components 2 on both sides. The rear end of the frame unit is provided with a tail wing servo 107, which is connected to a tail wing connector 108. The frame unit is also provided with a control unit and a battery 106 connected to each other. The control unit is not shown in the figure. In this embodiment, the first side plate 101 and the second side plate 102 are connected to each other. The 2 is provided with multiple through holes, and several channels are provided between the first side plate 101 and the second side plate 102 to facilitate wiring, heat dissipation and subsequent connection of other task modules. For example, the control unit can be fixed in the channel formed between the first side plate 101 and the second side plate 102 through the connector 103. The control unit is also provided with a wireless transmission module, the battery 106 is connected to a splitter board, and then the control unit is connected to a signal line to the splitter board. The splitter board then splits several lines to connect to all the motors, and the control unit realizes the control of each motor. The motors here include pitch angle adjustment motor, tail rudder motor and roll motor.

[0065] In this embodiment, the tail ends of the first side plate 101 and the second side plate 102 are fixed to each other by a tail plate 113. The tail plate 113 is provided with mounting holes, and the tail wing servo 107 is inserted into the mounting holes and fastened by bolts or other fasteners. The output shaft of the tail wing servo 107 can achieve stable assembly and replacement of the tail wing assembly 3 through a standardized servo disc structure.

[0066] (2) Two flapping wing adjustment units are symmetrically installed on both sides of the frame unit. Each flapping wing adjustment unit includes a pitch adjustment rod 109 with a U-shaped structure, a roll motor 110 and a rotating rod 111. The front middle part of the pitch adjustment rod 109 is connected to the output shaft of the pitch angle adjustment motor. The front end of the pitch adjustment rod 109 is equipped with a roll motor 110 to realize the flapping freedom in the roll direction. The output shaft of the roll motor 110 is connected to one end of the rotating rod 111 through a coupling. The other end of the rotating rod 111 is fixed to the end of the pitch adjustment rod 109 through a coupling. A flapping wing connector 112 is installed on the rotating rod 111 to stably transmit the lift on the flapping wing assembly 2 to the fuselage assembly 1.

[0067] In this embodiment, both the pitch angle adjustment motor and the roll motor 110 are Xiaomi DC brushless motors (CyberGear joint micro motors), and the tail servo is a 25KG·cm servo. The pitch angle adjustment motor and the roll motor on each side of the fuselage assembly 1 are connected in series in two stages of control and have independent degrees of freedom, which can realize the pitch and flapping angle adjustment of the flapping wing assembly respectively.

[0068] Preferably, the flapping wing connector 112 includes a rotating rod connector end and a flapping wing connector end. The rotating rod connector end includes three segments of claws 1121 that fit onto the rotating rod 111. The claws 1121 located at both ends of the rotating rod 111 are fixed to the rotating rod 111 by bolts. The flapping wing connector end is provided with a support frame 1122 that matches the side shape of the flapping wing frame 201 and is wider at the front and narrower at the back. Several ribs 1123 are provided at equal intervals inside the support frame 1122 to enhance strength. In addition, the flapping wing connector 112 also serves to avoid the aerodynamic effects caused by lateral air intake inside the cavity flapping wing.

[0069] Preferably, the first side plate 101, the second side plate 102, the connecting rod 103, and the tail plate 113 are all made of carbon fiber sheet and are laser-cut and processed. The pitch adjustment rod 109 is integrally formed by sheet metal bending, and the rotating rod 111 and each rod in each flapping wing frame 201 are made by cutting and drilling carbon fiber tubes.

[0070] II. See Figure 3 Each flapping wing assembly 2 includes a flapping wing frame 201, a composite spoiler structure 203, and a spoiler 204; the flapping wing assemblies 2 are symmetrically mounted on both sides of the fuselage assembly 1.

[0071] (1) The starting end of the flapping wing frame 201 in the outward direction is connected to the flapping wing connector 112. The flapping wing frame 201 has a frame structure that is thick at the front and thin at the tail, and is covered with a wing membrane 202 by thermal tension.

[0072] The wing membrane 202 is made of PET film material, and its overall cut outline fits the boundary of the flapping wing frame 201. The wing membrane 202 is laser-cut from carbon fiber sheet, and a special tensioning edge is provided at the membrane boundary. It is connected to the flapping wing frame 201 by double-sided adhesive tape for model aircraft, achieving a basic connection. The membrane tensioning process will follow.

[0073] The wing membrane 202 is tensioned by heat shrink tensioning. After the wing membrane 202 is fixed around the perimeter, the surface wrinkled area is heated by a hot air gun to achieve automatic shrink tensioning. The entire installation process of the wing membrane 202 is simple and can be completed without external clamps.

[0074] Preferably, a support rod is provided at the front of the flapping wing frame 201 along the outward direction, and several reinforcing ribs are sleeved on the support rod to improve bending stiffness and torsional performance and avoid stress concentration on one side. To ensure the overall dynamic coordination characteristics, the glider in this embodiment has been optimized in terms of rigidity distribution and weight balance. The periodic load generated when the flapping wing assembly 2 rotates is transmitted to the fuselage assembly 1 through the flapping wing adjustment unit. In flight, the movement of the flapping wing assembly 2 will cause periodic torque vibration. Therefore, the first-order resonant frequency of the fuselage assembly 1 needs to be much higher than the flapping frequency range to prevent structural resonance from interfering with flight stability. In actual testing, by increasing the thickness of each plate in the frame unit, the modal frequency of the fuselage assembly 1 was effectively increased to be higher than the 5 Hz flapping frequency of the flapping wing assembly 2, thus avoiding resonance. In this embodiment, the thickness of each plate in the frame unit is 3 mm. There are no plates in the flapping wing frame 201. The upper and lower surfaces are wing membranes. The flapping wing frame 201 is mainly constructed of carbon fiber tubes with a diameter of 8 mm.

[0075] Preferably, the width of the fuselage assembly 1 is approximately 8% to 12% of the length of a single flapping wing frame 201, and the aspect ratio (AR) of the flapping wing frame 201 ranges from 3 to 4. In this embodiment, the entire glider has a wingspan of 2.4 m, a length of 1050 mm for the flapping wing frame 201, and an aspect ratio of 3.1.

[0076] (2) In the structural design of the flapping wing assembly 2, in order to further improve the aerodynamic response characteristics and structural stability of the side wing edge region, a composite turbulence structure 203 is provided at the end (wingtip) of the flapping wing assembly in the outward direction. See Figure 4 The composite spoiler structure 203 is integrally formed by welding / adhesion and other methods, consisting of a fixed frame 2031, a guide vane 2032, a guide vane 2033, and a guide vane 2034. It is installed at the end of the flapping wing frame 201 in the outward direction through the fixed frame 2031. The composite spoiler structure 203 is arranged in a stepped or slightly divergent manner along the glider's forward direction. The lengths of the guide vanes 2032, 2033, and 2034 are not equal, and the longer the wing, the wider the width.

[0077] In this embodiment, the tilt angles of guide vanes 2034, 2033, and 2032 are 45°, 30°, and 15°, respectively; their widths are 33mm, 20mm, and 15mm, respectively; and their lengths are 9%, 7%, and 5.5% of the maximum length of the flapping wing frame 201, respectively, with the maximum length of the flapping wing frame 201 being 1050mm. This composite perturbation structure 203 possesses the aerodynamic function of inducing wake separation. During the high-speed reciprocating flapping motion of the flapping wing assembly, a strong wake vortex ring easily forms in the terminal region. This structure, through edge perturbation, can guide the airflow to detach along different paths, reducing the interference of concentrated wake vortices on flight attitude stability and suppressing wake vortices. Its edge perturbation can also effectively suppress the premature shedding of the boundary laminar flow of the flapping wing assembly, delaying the formation of the airflow separation point, thereby improving the linear consistency of the flapping lift curve, enabling the glider to possess both flapping and gliding capabilities.

[0078] The composite spoiler structure 203 is made of rigid material, forming a composite boundary structure with the flexible main material of the wing membrane 202. This enhances the deformation resistance of the wing tips, especially in cases of large flapping or sudden aerodynamic changes, helping to maintain the geometric stability of the flapping wing assembly edges. In actual flight, this structure also acts as a passive limiter and terminal buffer. When the flapping wing assembly deflects excessively or is subjected to external impact, the composite spoiler structure 203 can prevent further deformation of the membrane within a limited range, thereby avoiding structural damage or stress concentration.

[0079] (3) See Figure 4 The spoiler 204 is positioned at the front of the flapping wing frame 201, 680 mm from the root of the frame (the starting point of the flapping wing frame 201 in the outward direction). Located in the sensitive area of ​​airflow attachment and separation during flapping, the spoiler 204 is strip-shaped, 130 mm long, and angled upwards at 20° towards the composite spoiler structure 203. During flapping, the spoiler 204 generates localized turbulent airflow, inducing changes in the pressure difference between the upper and lower surfaces of the membrane wing, creating an auxiliary lift zone, and thus improving the asymmetric aerodynamic response during the flapping cycle. Especially during the downward phase of the flapping cycle, this structure delays the moment the airflow detaches from the wing surface, increasing the effective lift area of ​​the membrane wing during the downward phase and improving aerodynamic efficiency per unit stroke.

[0080] III. See Figure 5 In this embodiment, the tail fin assembly 3 is an isosceles triangular structure, and its planar structure is symmetrically arranged with the longitudinal axis of the fuselage assembly 1. It is connected to the fuselage assembly 1 via the tail fin connector 108. One end of the tail fin connector 108 is connected to the output shaft of the tail fin servo motor 107 via a rudder disk, and the other end is connected to the tail fin assembly 3 via screws, pins, or clamps, which allows for quick replacement of different types of tail fin assemblies.

[0081] The triangular tail assembly 3 exhibits excellent aerodynamic stability characteristics. Compared to rectangular or trapezoidal tail fins, the triangular tail assembly 3 has a larger critical stall angle under high angle of attack or large angle of attack flapping conditions, which helps maintain the adhesion of the tail flow field during violent flapping, thereby effectively suppressing the yaw and pitch instability of the aircraft.

[0082] Meanwhile, the delta tail assembly 3 can shorten the wingspan to a certain extent, reduce the lateral aerodynamic moment at the tail, reduce the control load, and facilitate rapid response in attitude control and direction adjustment, thereby improving turning ability and maneuverability during flight.

[0083] In addition, the tail assembly is connected to the fuselage assembly by an integrated structural component, which has strong structural rigidity and assembly stability. It can provide tail deformation resistance when the aircraft falls or is subjected to disturbance impact, thereby improving the fatigue strength and service life of the overall structure.

[0084] Preferably, the widest distance of the tail fin assembly 3 is 30% to 40% of the wingspan, the shortest distance of the tail fin assembly 3 is 3% to 6% of the wingspan, the tilt angle is 10 to 20 degrees, and the chord length of the tail fin assembly 3 is 50% to 60% of the chord length of the flapping wing frame 201. In this embodiment, the tail fin assembly 3 has a maximum width of 900 mm, a minimum width of 100 mm, a tilt angle of 15 degrees, and a chord length of 203 mm.

[0085] In this embodiment, the tail assembly, while maintaining pitch stabilization, further introduces a degree of freedom for roll control. By setting an independent tail servo 107 or a rotation mechanism, the tail assembly can actively deflect in the horizontal direction, thereby adjusting the glider's roll attitude. This design enhances the overall flexibility of flight control, especially in scenarios without main wing differential control, while still maintaining lateral attitude stability, effectively expanding the flight envelope, and providing more control dimensions to support intelligent control in complex environments.

[0086] Example 2

[0087] This embodiment provides a multi-degree-of-freedom flapping-wing glider with an aerodynamic shape. The glider is symmetrically designed and employs a lightweight, high-strength frame structure, providing rigid support and aerodynamic symmetry during flight. Specifically, it includes a fuselage assembly 1, two flapping-wing assemblies 2, and a tail assembly 3. (See attached image.) Figure 1 Specifically:

[0088] I. See Figure 2 The fuselage assembly 1 includes a frame unit and two flapping wing adjustment units;

[0089] (1) The frame unit is composed of a first side plate 101 and a second side plate 102 connected by multiple connectors 103. The front end of the frame unit is provided with an aerodynamic housing 104. The middle part of the frame unit is provided with a motor compartment 105. Two pitch angle adjustment motors are symmetrically installed in the motor compartment 105 to realize the pitch angle adjustment of the flapping wing components 2 on both sides. The rear end of the frame unit is provided with a tail wing servo 107, which is connected to a tail wing connector 108. The frame unit is also provided with a control unit and a battery 106 connected to each other. The control unit is not shown in the figure. In this embodiment, the first side plate 101 and the second side plate 102 are connected to each other. The 2 is provided with multiple through holes, and several channels are provided between the first side plate 101 and the second side plate 102 to facilitate wiring, heat dissipation and subsequent connection of other task modules. For example, the control unit can be fixed in the channel formed between the first side plate 101 and the second side plate 102 through the connector 103. The control unit is also provided with a wireless transmission module, the battery 106 is connected to a splitter board, and then the control unit is connected to a signal line to the splitter board. The splitter board then splits several lines to connect to all the motors, and the control unit realizes the control of each motor. The motors here include pitch angle adjustment motor, tail rudder motor and roll motor.

[0090] In this embodiment, the tail ends of the first side plate 101 and the second side plate 102 are fixed to each other by a tail plate 113. The tail plate 113 is provided with mounting holes, and the tail wing servo 107 is inserted into the mounting holes and fastened by bolts or other fasteners. The output shaft of the tail wing servo 107 can achieve stable assembly and replacement of the tail wing assembly 3 through a standardized servo disc structure.

[0091] (2) Two flapping wing adjustment units are symmetrically installed on both sides of the frame unit. Each flapping wing adjustment unit includes a pitch adjustment rod 109 with a U-shaped structure, a roll motor 110 and a rotating rod 111. The front middle part of the pitch adjustment rod 109 is connected to the output shaft of the pitch angle adjustment motor. The front end of the pitch adjustment rod 109 is equipped with a roll motor 110 to realize the flapping freedom in the roll direction. The output shaft of the roll motor 110 is connected to one end of the rotating rod 111 through a coupling. The other end of the rotating rod 111 is fixed to the end of the pitch adjustment rod 109 through a coupling. A flapping wing connector 112 is installed on the rotating rod 111 to stably transmit the lift on the flapping wing assembly 2 to the fuselage assembly 1.

[0092] In this embodiment, both the pitch angle adjustment motor and the roll motor 110 are Xiaomi DC brushless motors (CyberGear joint micro motors), and the tail servo is a 25KG·cm servo. The pitch angle adjustment motor and the roll motor on each side of the fuselage assembly 1 are connected in series in two stages of control and have independent degrees of freedom, which can realize the pitch and flapping angle adjustment of the flapping wing assembly respectively.

[0093] Preferably, the flapping wing connector 112 includes a rotating rod connector end and a flapping wing connector end. The rotating rod connector end includes three segments of claws 1121 that fit onto the rotating rod 111. The claws 1121 located at both ends of the rotating rod 111 are fixed to the rotating rod 111 by bolts. The flapping wing connector end is provided with a support frame 1122 that matches the side shape of the flapping wing frame 201 and is wider at the front and narrower at the back. Several ribs 1123 are provided at equal intervals inside the support frame 1122 to enhance strength. In addition, the flapping wing connector 112 also serves to avoid the aerodynamic effects caused by lateral air intake inside the cavity flapping wing.

[0094] Preferably, the first side plate 101, the second side plate 102, the pitch adjustment rod 109, the connecting rod 103, and the tail plate 113 are all made of carbon fiber sheets and are laser-cut and processed.

[0095] Preferably, the fuselage components may be constructed using honeycomb sandwich composite materials or multi-segment nested frames to further optimize weight distribution and modal control performance.

[0096] II. See Figure 3 Each flapping wing assembly 2 includes a flapping wing frame 201, a composite spoiler structure 203, and a spoiler 204; the flapping wing assemblies 2 are symmetrically mounted on both sides of the fuselage assembly 1.

[0097] (1) The starting end of the flapping wing frame 201 in the outward direction is connected to the flapping wing connector 112. The flapping wing frame 201 has a frame structure that is thick at the front and thin at the tail, and is covered with a wing membrane 202 by thermal tension.

[0098] An adjustable tensioning structure can also be provided at the tail of the flapping wing frame 201 to ensure that the glider remains flat during flight, stabilizes the aerodynamic profile, and prevents the wing membrane 202 from wrinkling, loosening, or oscillating during flapping, thereby improving the continuity of lift output and flight stability.

[0099] The wing membrane 202 is made of PVDF or composite PI membrane material, and its overall cut outline fits the boundary of the flapping wing frame 201. The wing membrane 202 is laser-cut from carbon fiber sheet, and a special tensioning edge is provided at the membrane boundary. It is connected to the flapping wing frame 201 by double-sided adhesive tape for model aircraft, achieving a basic connection. The membrane tensioning process will follow.

[0100] The tensioning of the wing membrane 202 is achieved dynamically by means of mechanical cable structure, magnetic tensioning ring or electrothermal film drive.

[0101] Dynamic tensioning can be achieved using mechanical cable structures, magnetic tensioning rings, or electrothermal film drives.

[0102] Preferably, a support rod is provided at the front of the flapping wing frame 201 along the outward direction, and several reinforcing ribs are sleeved on the support rod to improve bending stiffness and torsional performance and avoid stress concentration on one side. To ensure the overall dynamic coordination characteristics, the glider in this embodiment has been optimized in terms of rigidity distribution and weight balance. The periodic load generated when the flapping wing assembly 2 rotates is transmitted to the fuselage assembly 1 through the flapping wing adjustment unit. In flight, the movement of the flapping wing assembly 2 will induce periodic torque vibration. Therefore, the first-order resonant frequency of the fuselage assembly 1 needs to be much higher than the flapping frequency range to prevent structural resonance from interfering with flight stability. In actual testing, by increasing the thickness of each plate in the frame unit, the modal frequency of the fuselage assembly 1 was effectively increased, making it higher than the 5 Hz flapping frequency of the flapping wing assembly 2, thus avoiding resonance.

[0103] Preferably, the width of the fuselage assembly 1 is approximately 8% to 12% of the length of a single flapping wing frame 201, and the aspect ratio (AR) of the flapping wing frame 201 ranges from 3 to 4. In this embodiment, the entire glider has a wingspan of 2.4 m, a length of 1050 mm for the flapping wing frame 201, and an aspect ratio of 31.

[0104] (2) In the structural design of the flapping wing assembly 2, in order to further improve the aerodynamic response characteristics and structural stability of the side wing edge region, a composite turbulence structure 203 is provided at the end of the flapping wing assembly in the outward direction. See Figure 4 The composite spoiler structure 203 is integrally formed by welding / adhesion and other methods, consisting of a fixed frame 2031, a guide vane 2032, a guide vane 2033, and a guide vane 2034. It is installed at the end of the flapping wing frame 201 in the outward direction through the fixed frame 2031. The composite spoiler structure 203 is arranged in a stepped or slightly divergent manner along the glider's forward direction. The lengths of the guide vanes 2032, 2033, and 2034 are not equal, and the longer the wing, the wider the width.

[0105] In this embodiment, the tilt angles of guide vanes 2034, 2033, and 2032 are 50°, 35°, and 20°, respectively; their widths are 35mm, 25mm, and 16mm, respectively; and their lengths are 10%, 8%, and 6% of the maximum length of the flapping wing frame 201, respectively, with the maximum length of the flapping wing frame 201 being 1050mm. This composite perturbation structure 203 possesses the aerodynamic function of inducing wake separation. During the high-speed reciprocating flapping motion of the flapping wing assembly, a strong wake vortex ring easily forms in the terminal region. This structure, through edge perturbation, can guide the airflow to detach along different paths, reducing the interference of concentrated wake vortices on flight attitude stability and suppressing wake vortices. Its edge perturbation can also effectively suppress the premature shedding of the boundary laminar flow of the flapping wing assembly, delaying the formation of the airflow separation point, thereby improving the linear consistency of the flapping lift curve, enabling the glider to possess both flapping and gliding capabilities.

[0106] Similar aerodynamic control effects can also be achieved by using embedded micro-airway structures, variable stiffness edge layers, or microelectromechanical systems (MEMS) for flow control.

[0107] Embedded micro-air channel structure: The principle is to design a network of micron-level airflow channels inside the surface of an object (such as an airfoil or turbine blade), and change the surface pressure distribution or boundary layer state by actively or passively controlling the flow of air in the micro-channels.

[0108] Variable stiffness edge layer: The principle is to create a flexible layer with variable stiffness on the surface of an object by using smart materials (such as shape memory alloys, piezoelectric materials or electroactive polymers) to dynamically change the surface morphology or hardness.

[0109] Microelectromechanical flow control elements (MEMS): The principle is to use microelectromechanical system (MEMS) technology to integrate micro sensors and actuators (such as micro valves, jet nozzles or plasma actuators) to sense and regulate airflow in real time.

[0110] The composite spoiler structure 203 is made of rigid material, forming a composite boundary structure with the flexible main material of the wing membrane 202. This enhances the deformation resistance of the wing tips, especially in cases of large flapping or sudden aerodynamic changes, helping to maintain the geometric stability of the flapping wing assembly edges. In actual flight, this structure also acts as a passive limiter and terminal buffer. When the flapping wing assembly deflects excessively or is subjected to external impact, the composite spoiler structure 203 can prevent further deformation of the membrane within a limited range, thereby avoiding structural damage or stress concentration.

[0111] (3) See Figure 4 The spoiler 204 is positioned at the front of the flapping wing frame 201, 735 mm from the root of the frame (the starting point of the flapping wing frame 201 in the outward direction). Located in the sensitive area of ​​airflow attachment and separation during flapping, the spoiler 204 is wing-shaped, 140 mm long, and angled upwards at 17° towards the composite spoiler structure 203. During flapping, the spoiler 204 generates localized turbulent airflow, inducing changes in the pressure difference between the upper and lower surfaces of the membrane wing, creating an auxiliary lift zone, and thus improving the asymmetric aerodynamic response during the flapping cycle. Especially during the downward phase of the flapping cycle, this structure delays the moment the airflow detaches from the wing surface, increasing the effective lift area of ​​the membrane wing during the downward phase and improving aerodynamic efficiency per unit distance.

[0112] III. In this embodiment, the tail fin assembly 3 has a trapezoidal or V-shaped structure, and its planar structure is symmetrically arranged with the longitudinal axis of the fuselage assembly 1. It is connected to the fuselage assembly 1 via the tail fin connector 108. One end of the tail fin connector 108 is connected to the output shaft of the tail fin servo motor 107 via a rudder disc, and the other end is connected to the tail fin assembly 3 via a magnetic or quick-plug structure, which allows for quick replacement of different types of tail fin assemblies.

[0113] In addition, the tail assembly is connected to the fuselage assembly by an integrated structural component, which has strong structural rigidity and assembly stability. It can provide tail deformation resistance when the aircraft falls or is subjected to disturbance impact, thereby improving the fatigue strength and service life of the overall structure.

[0114] Preferably, the widest distance of the tail fin assembly 3 is 30% to 40% of the wingspan, the shortest distance of the tail fin assembly 3 is 3% to 6% of the wingspan, the tilt angle is 10 to 20 degrees, and the chord length of the tail fin assembly 3 is 50% to 60% of the wing chord length. In this embodiment, the tail fin assembly 3 has a maximum width of 800 mm, a minimum width of 100 mm, a tilt angle of 18 degrees, and a chord length of 203 mm.

[0115] In this embodiment, the tail assembly, while maintaining pitch stabilization, further introduces a degree of freedom for roll control. By setting an independent tail servo 107 or a rotation mechanism, the tail assembly can actively deflect in the horizontal direction, thereby adjusting the glider's roll attitude. This design enhances the overall flexibility of flight control, especially in scenarios without main wing differential control, while still maintaining lateral attitude stability, effectively expanding the flight envelope, and providing more control dimensions to support intelligent control in complex environments.

[0116] This utility model is not limited to the embodiments described above. The above description of specific embodiments is intended to illustrate and explain the technical solution of this utility model. The specific embodiments described above are merely illustrative and not restrictive. Without departing from the spirit and scope of protection of this utility model and the claims, those skilled in the art can make many specific modifications based on the teachings of this utility model, and these modifications all fall within the protection scope of this utility model.

Claims

1. A multi-degree-of-freedom flapping-wing glider with an aerodynamic shape, characterized in that, The overall design is symmetrical, consisting of a fuselage assembly, two flapping wing assemblies, and a tail assembly; The fuselage components include: A frame unit is formed by connecting a first side plate and a second side plate through several connectors. The front end of the frame unit is provided with an aerodynamic shell. The middle part of the frame unit is provided with a motor compartment, and the motor compartment is provided with two pitch angle adjustment motors. The rear end of the frame unit is equipped with a tail fin servo, and the tail fin servo is connected to a tail fin connector. A battery is also installed inside the frame unit. Two flapping wing adjustment units are respectively installed on both sides of the frame unit. Each flapping wing adjustment unit includes a pitch adjustment rod with a U-shaped structure, a roll motor, and a rotating rod. The pitch adjustment rod is connected to the output shaft of the pitch angle adjustment motor. The roll motor is installed at the front end of the pitch adjustment rod. The output shaft of the roll motor is connected to one end of the rotating rod through a coupling. The other end of the rotating rod is fixed to the end of the pitch adjustment rod through a coupling. A flapping wing connector is installed on the rotating rod. Each of the flapping wing assemblies includes: The flapping wing frame has its starting end in the outward direction connected to the flapping wing connector. The flapping wing frame has an overall frame structure that is thick at the front and thin at the rear, and is covered with a wing membrane by thermal tensioning. The composite turbulence structure is formed by an integral fixed connection of a fixed frame and three guide vanes. The fixed frame is installed at the end of the flapping wing frame in the outward direction. The area of ​​the three guide vanes decreases from front to back and the angle of their tilt decreases at equal angles. The spoiler is strip-shaped and is located at the front of the flapping wing frame at a distance of 0.6 to 0.7 times the length of the flapping wing frame. The spoiler forms an angle with the flapping wing frame and is inclined towards the direction of the composite spoiler structure. The tail fin assembly has a triangular, trapezoidal, or V-shaped structure and is connected to the frame unit via the tail fin connector.

2. The multi-degree-of-freedom flapping-wing glider with an aerodynamic shape according to claim 1, characterized in that, The tilt angle of the guide vane ranges from 10° to 50°. The length of a single guide vane accounts for 5% to 10% of the total length of a single flapping wing frame, and the lengths of each guide vane are not equal. The width of a single guide vane is 25% to 35% of its own length.

3. The multi-degree-of-freedom flapping-wing glider with an aerodynamic shape according to claim 1, characterized in that, The tail ends of the first side plate and the second side plate are fixed to each other by a tail plate, which has mounting holes. The tail fin servo is inserted into the mounting holes and fastened by fasteners.

4. The multi-degree-of-freedom flapping-wing glider with an aerodynamic shape according to claim 1, characterized in that, The first side plate, the second side plate, and the connecting rod are all made of carbon fiber sheet and are laser-cut and processed. The pitch adjustment rod is integrally formed by sheet metal bending. The rotating rod and each rod in each flapping wing frame are made of carbon fiber tubes cut and drilled. Several through holes are provided on the first side plate and the second side plate, and several channels are provided between the first side plate and the second side plate to facilitate wiring, heat dissipation, and subsequent connection of other task modules.

5. A multi-degree-of-freedom flapping-wing glider with an aerodynamic shape according to claim 4, characterized in that, A control unit connected to the battery is installed in the channel via the connector. The control unit is equipped with a wireless transmission module and is connected to the pitch adjustment motor, tail fin servo, and roll motor.

6. A multi-degree-of-freedom flapping-wing glider with an aerodynamic shape according to claim 1, characterized in that, The flapping wing connector includes a rotating rod connector and a flapping wing connector. The rotating rod connector includes three segments of claws that fit onto the rotating rod. The two ends of the claws are fixed to the rotating rod by fasteners. The flapping wing connector is provided with a support frame that fits the side shape of the flapping wing frame and is wider at the front and narrower at the back. Several ribs are provided at equal intervals in the support frame to increase strength and prevent the flapping wing frame from laterally entering the air.

7. A multi-degree-of-freedom flapping-wing glider with an aerodynamic shape according to claim 1, characterized in that, The front part of the flapping wing frame is provided with a support rod along the outward direction. Several reinforcing ribs are sleeved on the support rod to improve bending stiffness and torsional performance and avoid stress concentration on one side. The first-order modal frequency of the flapping wing frame is higher than the flapping frequency of the flapping wing assembly.

8. A multi-degree-of-freedom flapping-wing glider with an aerodynamic shape according to claim 1, characterized in that, One end of the tail fin connector is connected to the tail fin servo output shaft via a rudder disc, and the other end is connected to the tail fin assembly via a combination of bolts and pins, enabling quick replacement of different types of tail fin assemblies; the tail fin assembly is an isosceles triangular tail fin.

9. A multi-degree-of-freedom flapping-wing glider with an aerodynamic shape according to claim 1, characterized in that, The length of the spoiler is within 10% to 15% of the length of the front end of the corresponding flapping wing frame, and the tilt angle is 15 to 25°.

10. A multi-degree-of-freedom flapping-wing glider with an aerodynamic shape according to claim 1, characterized in that, The wing membrane is any one of PET film, PVDF film or composite PI film, and is laser-cut to obtain the basic shape. Then, the outer edge of the film is glued to the flapping wing frame. Finally, the wrinkled area in the middle of the film wing is heated by a hot air gun to achieve self-tensioning.

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