A variable-angle crank-rocker adaptive bionic butterfly flight mechanism and its driving method

Abstract

This invention discloses a variable-angle crank-rocker adaptive bionic butterfly flight mechanism and its driving method, belonging to the field of bionic butterfly technology. It includes symmetrically arranged bionic forewings and symmetrically arranged bionic rearwings. The symmetrically arranged forewings are connected by a variable-angle crank-rocker assembly, and the symmetrically arranged rearwings are connected by the same assembly. The two variable-angle crank-rocker assemblies are connected by a stabilizing shaft mechanism. The variable-angle crank-rocker assembly includes a frame with a symmetrical synchronous engagement mechanism on it. Symmetrical crank-connecting rod mechanisms are arranged on both sides of the frame, and these mechanisms are connected to the synchronous engagement mechanism. This invention, employing the aforementioned variable-angle crank-rocker adaptive bionic butterfly flight mechanism and driving method, solves the problems of complex mechanical structures, poor flight maneuverability and flexibility, inability to achieve wing-standing with a single crank, inconsistent frequencies between the left and right wings, and low flight efficiency in existing bionic butterflies.

Description

Technical Field

[0001] This invention relates to the field of biomimetic butterfly technology, and in particular to a variable-angle crank-rocker adaptive biomimetic butterfly flight mechanism and driving method. Background Technology

[0002] Traditional drones (such as multi-rotor aircraft) are limited in practical applications due to their high flight noise and obvious target features, which easily reveal their location and mission intentions. Against this backdrop, low-noise, highly stealthy biomimetic flapping-wing aircraft have emerged. By mimicking the flight patterns of birds or insects, they use mechanical and electronic control devices to drive the wings to flap back and forth, generating lift and thrust while also controlling attitude. Micro-flapping-wing platforms, exemplified by the "bionic butterfly," can be compressed to the tens of centimeters in size, offering superior portability, stealth, and maneuverability compared to other flapping-wing configurations. They can move flexibly in confined spaces and perform more complex tasks.

[0003] Most existing biomimetic butterfly aircraft have overly complex mechanical structures, making it difficult for operators to make precise and smooth real-time adjustments to their flight status via remote control during actual operation. Furthermore, the overly complex mechanical structure directly results in a large overall weight, severely weakening the aircraft's maneuverability and flexibility, significantly reducing its flight performance, and resulting in insufficient overall controllability.

[0004] Existing biomimetic butterfly aircraft almost all use typical transmission mechanisms such as single crank double rocker or crank-slide mechanism. The fundamental characteristic of these mechanisms is that a single, rigid crank serves as the power output element, which simultaneously connects to the rocker or wing drive mechanisms on both the left and right sides.

[0005] Its trajectory and extreme positions are entirely determined by the geometry and fixed length of this crank. That is, it cannot achieve, for example, vertically folding and fitting against the sides of the body. In other words, any mechanism based on a single rigid crank cannot mathematically support an upright wing posture in its kinematic model. It is completely unable to replicate the posture of a biomimetic butterfly when perched or landing, resulting in insufficient biomimetic fidelity and the loss of the ability to use folded wings for rapid deceleration and covert landing.

[0006] At the same time, when a single crank rigid connection is chosen, the direct consequence is that even with minor manufacturing errors, the lift and thrust will be asymmetrical, manifesting as the left and right wings operating at different frequencies, leading to flight instability, and also resulting in the negative effects of a complex, bulky, and inefficient structure. Summary of the Invention

[0007] The purpose of this invention is to provide a variable-angle crank-rocker adaptive bionic butterfly flight mechanism and driving method, which solves the problems of complex mechanical structure, poor flight maneuverability and flexibility, inability of single crank to achieve wing erection, different frequencies of left and right wings, and low flight efficiency of existing bionic butterflies.

[0008] To achieve the above objectives, the present invention provides a variable-angle crank-rocker adaptive bionic butterfly flight mechanism, comprising symmetrically arranged bionic forewings and symmetrically arranged bionic rearwings. The symmetrically arranged bionic forewings are connected by a variable-angle crank-rocker assembly, and the symmetrically arranged bionic rearwings are connected by a variable-angle crank-rocker assembly. The variable-angle crank-rocker assembly of the bionic forewings and the variable-angle crank-rocker assembly of the bionic rearwings are connected by a stabilizing shaft mechanism. The variable angle crank rocker assembly includes a frame, on which a symmetrical synchronous meshing mechanism is provided, and on both sides of the frame are symmetrical crank-connecting rod mechanisms, which are connected to the symmetrical synchronous meshing mechanism.

[0009] Preferably, the symmetrical synchronous meshing mechanism includes rocker arm one and rocker arm two symmetrically arranged on the frame. One end of rocker arm one and one end of rocker arm two are respectively hinged to the frame. The other end of rocker arm one is connected to the bionic forewing or the bionic rearwing, and the other end of rocker arm two is connected to the bionic forewing or the bionic rearwing.

[0010] Preferably, rocker arm one and rocker arm two are connected by toothed engagement and move synchronously.

[0011] Preferably, the symmetrical crank-connecting rod mechanism includes a crank one and a crank two arranged symmetrically, and a drive structure one and a drive structure two are symmetrically arranged on the frame. The output end of the drive structure one is connected to the center of the crank one, and the output end of the drive structure two is connected to the center of the crank two.

[0012] Preferably, one end of crank one is hinged to one end of vertical wing rod one, the other end of vertical wing rod one is hinged to one end of connecting rod one, one end of crank two is hinged to one end of vertical wing rod two, the other end of vertical wing rod two is hinged to one end of connecting rod two, and vertical wing rod one and vertical wing rod two are arranged symmetrically. The end of connecting rod one away from the first vertical wing rod is hinged to the end of rocker arm one away from the tooth engagement, and the end of connecting rod two away from the second vertical wing rod is hinged to the end of rocker arm two away from the tooth engagement. Connecting rod one and connecting rod two are arranged symmetrically.

[0013] Preferably, crank one and wing rod one, and crank two and wing rod two are slidable to achieve relative rotation. A limiting protrusion is provided at one end of crank one near the hinge point with wing rod one, and at one end of crank two near the hinge point with wing rod two. Limiting blocks adapted to the limiting protrusions are provided on wing rod one and wing rod two. During normal flight, limiting platform two restricts the rotation of limiting platform one, thereby fixing crank one and wing rod one, and crank two and wing rod two, into a whole. During upright flight, crank one and upright wing rod one, and crank two and upright wing rod two rotate relative to each other, causing the bionic forewing and bionic hindwing to become upright. Here, the limiting protrusion and the limiting block form a locking limit, restricting the continued rotation of crank one and upright wing rod one, and crank two and upright wing rod two. Crank one, upright wing rod one, and connecting rod one form a three-link linkage, and crank two, upright wing rod two, and connecting rod two form a three-link linkage.

[0014] A limiting platform 1 is provided at the end of crank 1 away from its hinge point with vertical wing rod 1, and at the end of crank 2 away from its hinge point with vertical wing rod 2. A limiting platform 2 adapted to the limiting platform 1 is provided on vertical wing rod 1 and vertical wing rod 2.

[0015] Preferably, a protective plate is provided on the side of rocker arm one and rocker arm two away from the frame, and rocker arm one and rocker arm two are located between the protective plate and the frame.

[0016] Preferably, the stabilizing axis mechanism includes a connecting shaft and a connecting rod. The connecting shaft passes sequentially through the upper end of the protective plate at the bionic forewing and the upper end of the frame, and then sequentially through the upper end of the protective plate at the bionic rear wing and the upper end of the frame. The connecting rod passes sequentially through the lower end of the protective plate at the bionic forewing and the lower end of the frame, and then sequentially through the lower end of the protective plate at the bionic rear wing and the lower end of the frame.

[0017] Preferably, a steering servo is provided on the connecting rod, and the output end of the steering servo is connected to the battery casing.

[0018] The present invention also provides a driving method for a variable-angle crank-rocker adaptive bionic butterfly flight mechanism, including a normal flapping-wing flight mode and a standing-wing flight mode; In normal flapping-wing flight mode, the output end of drive structure one drives crank one to rotate counterclockwise, and the output end of drive structure two drives crank two to rotate clockwise. Crank one is fixed to the vertical wing rod one, and crank two is fixed to the vertical wing rod two. The output ends of drive structure one and drive structure two respectively drive crank one and crank two to rotate synchronously. Crank one and vertical wing rod one together drive connecting rod one to swing back and forth. Crank two and vertical wing rod two together drive connecting rod two to swing back and forth. The swinging of connecting rod one and connecting rod two drives rocker one and rocker two to swing back and forth, which in turn drives the symmetrically arranged bionic forewing to swing back and forth and the symmetrically arranged bionic rearwing to swing back and forth. In the upright wing flight mode, the output end of drive structure one drives crank one to rotate clockwise, and the output end of drive structure two drives crank two to rotate counterclockwise. The fixation between crank one and upright wing rod one is released, and the fixation between crank two and upright wing rod two is released. The output ends of drive structure one and drive structure two respectively drive crank one and crank two to rotate synchronously with fine adjustment. Crank one pushes connecting rod one to rotate through upright wing rod one, and crank two pushes connecting rod two to rotate through upright wing rod two. Connecting rod one and connecting rod two respectively push rocker one and rocker two to swing synchronously.

[0019] The advantages and positive effects of the variable-angle crank-rocker adaptive bionic butterfly flight mechanism and driving method described in this invention are as follows: 1. The traditional crank-rocker mechanism splits the single integral crank into two independent parts, the crank and the upright wing rod, which can rotate relative to each other. With the help of limiting protrusions, limiting blocks, and limiting platforms, angular limiting and mechanical self-locking are formed between the crank and the upright wing rod. The locking / unlocking state is switched by the steering of the drive structure, thereby realizing the switching between the normal flapping wing and upright wing working modes. Two motion functions are integrated on a single transmission mechanism. 2. Set meshing teeth at the roots of the two symmetrical rockers to form a synchronous gear. The movement of the two rockers is constrained by the meshing transmission, so that the swing angles of the two rockers are kept symmetrical, thereby solving the problem of different phases and inconsistent frequencies of the flapping of the left and right wings in the existing mechanism. 3. In normal flapping mode, the constraint of synchronous meshing transmission between the crank and the upright wing rod keeps the mechanism in a self-locking state, ensuring stable output of flapping action and avoiding accidental mode switching during flight; in upright wing mode, the mechanism unlocks and releases degrees of freedom, enabling the adjustment of the bionic wings to stand up. 4. The integrated miniature steering servo drives the battery to rotate and change the battery position, causing the overall center of gravity to shift off the central axis, thus achieving rapid yaw and steering, solving the steering lag problem of existing technologies. At the same time, the lightweight design of this structure will not add too much weight to the whole machine.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the variable angle crank-rocker adaptive bionic butterfly flight mechanism of the present invention; Figure 2 This is a schematic diagram of the connection of the variable angle crank-rocker assembly in an embodiment of the adaptive bionic butterfly flight mechanism of the present invention; Figure 3 This is a schematic diagram of the variable angle crank-rocker assembly structure of an embodiment of the adaptive bionic butterfly flight mechanism of the present invention; Figure 4This is a schematic diagram of a symmetrical synchronous meshing mechanism according to an embodiment of a variable-angle crank-rocker adaptive bionic butterfly flight mechanism of the present invention; Figure 5 This is a schematic diagram of the connection between the crank and the wing rod in an embodiment of the variable angle crank-rocker adaptive bionic butterfly flight mechanism of the present invention; Figure 6 This is a schematic diagram of the crank structure of an embodiment of the variable angle crank-rocker adaptive bionic butterfly flight mechanism of the present invention; Figure 7 This is a schematic diagram of the wing rod structure of an embodiment of the variable angle crank-rocker adaptive bionic butterfly flight mechanism of the present invention; Figure 8 This is a schematic diagram of the internal connection between the crank and the wing rod in an embodiment of the variable angle crank-rocker adaptive bionic butterfly flight mechanism of the present invention; Figure 9 This is a schematic diagram of the normal flapping-wing flight mode of an embodiment of the variable-angle crank-rocker adaptive bionic butterfly flight mechanism of the present invention; Figure 10 This is a schematic diagram of the upright wing flight mode of an embodiment of the variable angle crank rocker adaptive bionic butterfly flight mechanism of the present invention.

[0022] Figure label: 1. Bionic forewing; 2. Bionic rearwing; 3. Variable angle crank-rocker assembly; 4. Frame; 5. Rocker arm one; 6. Rocker arm two; 7. Crank one; 8. Crank two; 9. Drive structure one; 10. Drive structure two; 11. Elevator rod one; 12. Elevator rod two; 13. Connecting rod one; 14. Connecting rod two; 15. Limiting protrusion; 16. Limiting block; 17. Limiting platform one; 18. Limiting platform two; 19. Protective plate; 20. Connecting shaft; 21. Connecting rod; 22. Steering servo; 23. Battery. Detailed Implementation

[0023] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.

[0025] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0026] Example: like Figure 1 As shown, the adaptive bionic butterfly flight mechanism of the present invention includes two symmetrically arranged bionic forewings 1 and two symmetrically arranged bionic rearwings 2. The two symmetrically arranged bionic forewings 1 are connected by a variable angle crank rocker assembly 3, and the two symmetrically arranged rearwings 2 are connected by a variable angle crank rocker assembly 3.

[0027] like Figure 2 , Figure 3 As shown, the variable angle crank-rocker assembly 3 includes a frame 4, on which a symmetrical synchronous meshing mechanism is mounted. Symmetrical crank-connecting rod mechanisms are mounted on both sides of the frame 4, and the symmetrical crank-connecting rod mechanisms are connected to the symmetrical synchronous meshing mechanism. The frame 4 is made of lightweight carbon fiber or PLA, providing a mounting base for all transmission and drive components. The mounting reference plane of the entire machine is located at the central axis of the frame 4, ensuring the symmetry of the left and right mechanisms.

[0028] like Figure 4As shown, the symmetrical synchronous meshing mechanism includes rocker arm 5 and rocker arm 6 symmetrically arranged on the frame 4. One end of rocker arm 5 and one end of rocker arm 6 are hinged to the frame 4. The other end of rocker arm 5 is connected to either the bionic forewing 1 or the bionic rearwing 2, and the other end of rocker arm 6 is also connected to either the bionic forewing 1 or the bionic rearwing 2. Rocker arm 5 and rocker arm 6 are connected by toothed meshing and move synchronously, forming a 1:1 transmission ratio. The function of this structure is to constrain the movement of the left and right rocker arms 5 and 6, ensuring that their swing angles remain symmetrical, avoiding problems such as different flapping phases and inconsistent frequencies between the left and right wings, and ensuring the synchronicity of the flapping action.

[0029] The symmetrical crank-connecting rod mechanism includes crank 7 and crank 8 symmetrically arranged. Drive structure 9 and drive structure 10 are symmetrically arranged on the frame 4. The output end of drive structure 9 is connected to the center of crank 7, and the output end of drive structure 10 is connected to the center of crank 8. Both drive structure 9 and drive structure 10 can be miniature drive motors.

[0030] One end of crank 7 is hinged to one end of vertical wing rod 11, and the other end of vertical wing rod 11 is hinged to one end of connecting rod 13. One end of crank 8 is hinged to one end of vertical wing rod 12, and the other end of vertical wing rod 12 is hinged to one end of connecting rod 14. Vertical wing rod 11 and vertical wing rod 12 are symmetrically arranged. The end of connecting rod 13 away from vertical wing rod 11 is hinged to the end of rocker arm 5 away from tooth engagement, and the end of connecting rod 14 away from vertical wing rod 12 is hinged to the end of rocker arm 6 away from tooth engagement. Connecting rod 13 and connecting rod 14 are symmetrically arranged. This invention provides a split design for the traditional single integral crank, dividing the original crank into two independent parts: the crank and the vertical wing rod.

[0031] like Figure 5 , Figure 6 , Figure 7 , Figure 8 As shown, crank 7 and vertical wing rod 11, and crank 8 and vertical wing rod 2 12 are slidable to achieve relative rotation. A limiting protrusion 15 is provided at the end of crank 7 near its hinge point with vertical wing rod 11, and at the end of crank 8 near its hinge point with vertical wing rod 2 12. Limiting blocks 16 adapted to the limiting protrusion 15 are provided on vertical wing rod 11 and vertical wing rod 2 12. A limiting platform 17 is provided at the end of crank 7 away from its hinge point with vertical wing rod 11, and at the end of crank 8 away from its hinge point with vertical wing rod 2 12. A limiting platform 2 18 adapted to the limiting platform 17 is provided on vertical wing rod 11 and vertical wing rod 2 12.

[0032] This invention converts the rotational motion of the crank into the reciprocating oscillation of the rocker arm, thereby driving the wing to complete the flapping motion. During normal flight, the limiting platform 2 18 restricts the rotation of the limiting platform 17, thus fixing the crank 1 7 and the wing support 1 11, and the crank 2 8 and the wing support 2 12 as a single unit. During stand-up flight, the crank 1 7 and the wing support 1 11, and the crank 2 8 and the wing support 2 12 rotate relative to each other, causing the bionic forewing 1 and the bionic rearwing 2 to stand up. Here, the limiting protrusion 15 and the limiting block 16 form a locking limit, restricting the continued rotation of the crank 1 7 and the wing support 11, and the crank 2 8 and the wing support 2 12. The crank 1 7, the wing support 11, and the connecting rod 13 form a three-link linkage, and the crank 2 8, the wing support 2 12, and the connecting rod 2 14 form a three-link linkage.

[0033] The variable angle crank-rocker assembly 3 of the bionic forewing wing 1 and the variable angle crank-rocker assembly 3 of the bionic rear wing 2 are connected by a stabilizing shaft mechanism. A protective plate 19 is provided on the side of rocker arm 5 and rocker arm 6 away from the frame 4, and rocker arm 5 and rocker arm 6 are located between the protective plate 19 and the frame 4.

[0034] The stabilizing axis mechanism includes a connecting shaft 20 and a connecting rod 21. The connecting shaft 20 passes through the upper end of the protective plate 19 at the bionic forewing 1 and the upper end of the frame 4 in sequence, and then passes through the upper end of the protective plate 19 at the bionic rear wing 2 and the upper end of the frame 4 in sequence. The connecting rod 21 passes through the lower end of the protective plate 19 at the bionic forewing 1 and the lower end of the frame 4 in sequence, and then passes through the lower end of the protective plate 19 at the bionic rear wing 2 and the lower end of the frame 4 in sequence.

[0035] A steering servo 22 is mounted on the connecting rod 21, and the output end of the steering servo 22 is connected to the casing of the battery 23. The steering servo 22 is fixed in the middle of the connecting rod 21 (carbon rod) of the fuselage, and drives the battery 23 to rotate, changing the position of the battery 23, so that the overall center of gravity shifts off the central axis, thereby achieving rapid yaw and steering.

[0036] The biomimetic forewing 1 and biomimetic hemiwing 2 are made of carbon fiber skeleton covered with lightweight PET film. Each wing is 17.5cm long, with a total wingspan of 39cm. The wing root is aligned with the end of the joystick, allowing the flapping angle to inherit the joystick's 100° swing amplitude, consistent with the flapping characteristics of a real butterfly. Extensive experiments have shown that significant lift is generated at a 100° swing angle and a stroke-to-speed ratio coefficient K of 1.09. The entire device utilizes lightweight materials such as carbon fiber skeleton and PET film to construct components, achieving multi-mode functionality while maintaining overall lightweight design, improving the aircraft's maneuverability and portability.

[0037] like Figure 9 , Figure 10As shown, the driving method of the variable angle crank rocker adaptive bionic butterfly flight mechanism of the present invention includes a normal flapping wing flight mode (normal flight state) and a standing wing flight mode (special attitude adjustment state).

[0038] In normal flapping-wing flight mode, the output end of drive structure 19 drives crank 7 to rotate counterclockwise, and the output end of drive structure 210 drives crank 28 to rotate clockwise. Crank 17 is fixed to the vertical wing rod 11, and crank 28 is fixed to the vertical wing rod 212. They rotate synchronously with the output end of the drive structure. At this time, the whole is equivalent to a traditional symmetrical double crank double rocker mechanism.

[0039] The output ends of drive structure 19 and drive structure 20 respectively drive crank 17 and crank 28 to rotate synchronously. Crank 17 and vertical wing rod 11 together drive connecting rod 13 to swing back and forth. Crank 28 and vertical wing rod 22 together drive connecting rod 24 to swing back and forth. The swinging of connecting rod 13 and connecting rod 24 drives rocker arm 15 and rocker arm 26 to swing back and forth, thereby driving the symmetrically arranged bionic forewing 1 to swing back and forth and the symmetrically arranged bionic rearwing 2 to swing back and forth.

[0040] Due to the synchronous meshing of the roots of the left and right rockers, their movements are strictly constrained to be symmetrical. The swing angle of rocker 5 is completely consistent with that of rocker 6, ensuring that the left and right wings complete the up-and-down flapping at the same frequency and amplitude. This transforms the rotational motion of the drive structure into the reciprocating flapping of the bionic wings (bionic forewing 1 and bionic rearwing 2), generating the lift and thrust required for flight.

[0041] In this mode, the synchronous meshing constraint between the crank and the vertical wing rod makes the entire mechanism self-locking: no matter how the driving torque changes, the crank section cannot rotate relative to the rocker arm, and the rocker arm cannot deflect additionally, ensuring stable output of flapping action, avoiding accidental switching of the mechanism during flight, and ensuring flight stability.

[0042] In the upright-wing flight mode (completing the upright-wing maneuver, used for traversing narrow spaces, adjusting flight attitude, or completing a hovering maneuver, etc.), the output end of drive structure 9 drives crank 7 to rotate clockwise, and the output end of drive structure 10 drives crank 8 to rotate counterclockwise; the fixation between crank 7 and upright-wing rod 11 is released, and the fixation between crank 8 and upright-wing rod 12 is released. At this time, each crank, rocker arm, and connecting rod transforms into a three-bar linkage, and the degree of freedom of the mechanism is released.

[0043] The output ends of drive structure 19 and drive structure 20 respectively drive crank 17 and crank 28 to rotate synchronously with fine adjustment, causing the vertical wing rod to disengage from the crank. Crank 17 drives connecting rod 13 to rotate through vertical wing rod 11, and crank 28 drives connecting rod 24 to rotate through vertical wing rod 212. Connecting rod 13 and connecting rod 24 respectively drive rocker arm 15 and rocker arm 26 to swing synchronously.

[0044] Due to the synchronous meshing action, the inward swing angles of the left and right rockers remain completely symmetrical, eventually driving the bionic wings from a horizontal flapping posture to a vertical wing posture standing upright on both sides of the frame 4, thus completing the wing-standing action.

[0045] In this mode, the posture of the bionic wings can be adjusted, enabling the bionic butterfly to perform wing-standing movements similar to those of a real butterfly, to pass through narrow spaces with smaller widths, or to perform wing-folding movements when perching.

[0046] When it is necessary to adjust the yaw attitude of the flight, the steering servo 22 is activated. By deflecting the battery in the target direction, the center of gravity of the aircraft is changed, generating a rolling torque to achieve the left and right yaw of the aircraft, improve the steering response speed, and solve the problems of steering lag and instability in the existing technology.

[0047] This invention overcomes the kinematic limitations of a single crank mechanism, achieving stable operation in both flapping and upright wing modes: Because this invention decomposes the traditional rigid single crank into a relatively rotatable active base and an action execution part, and sets an angle limit and mechanical self-locking structure between the two, the mechanism gains the ability to change its equivalent geometric constraints. In flapping wing mode, the self-locking structure fixes the two parts together, and the mechanism is equivalent to a rigid crank. When a flapping wing command is received, the self-locking force is overcome by reversing the drive structure, causing the two parts to disengage from the limit surface. The action execution part rotates relative to the wing, and then guides and maintains the bionic wing in a vertically folded posture via a rocker arm. This solution fundamentally changes the problem of low freedom and a single motion mode in existing single crank mechanisms, enabling the same drive mechanism to provide two distinctly different steady-state motion modes for the first time. Therefore, this invention provides aircraft with a flight mode for aerodynamic deceleration and covert landing through wing folding, significantly improving biomimetic accuracy and mission adaptability.

[0048] This invention physically eliminates the phase error between the left and right wings by forcibly synchronizing them using gears, thereby improving flight stability. A synchronous meshing structure is introduced between the left and right cranks, ensuring strict coupling of the angular velocities and rotational phases of the two cranks. Regardless of differences in aerodynamic loads on the left and right bionic wings, and regardless of manufacturing gaps or wear in the kinematic pairs, the two rockers are forced to move in a mirror-symmetrical manner. This eliminates the cumulative phase difference caused by asymmetry in the transmission chains on both sides, a problem present in existing technologies. The improved synchronization of the left and right bionic wing movements directly eliminates undesirable roll and yaw moments caused by asymmetry in lift or thrust during flight, resulting in a cleaner attitude reference for the aircraft and eliminating the need for continuous compensation for synchronization deviations by the control system.

[0049] The high degree of functional integration in this invention brings about a combined benefit of structural simplification and lightweight design: By integrating the uprighting wing function into the flapping wing powertrain through a variable-angle crank mechanism, a separate set of servos, linkages, and locking devices is eliminated for the wing-folding action. Simultaneously, a forced synchronous meshing structure replaces the multiple series-connected components and elastic compensation elements used in traditional designs for phase adjustment. This functional integration of the two core mechanisms significantly reduces the number of parts in the transmission chain, as well as the number of kinematic pairs and assembly steps. This structural simplification directly reduces the overall weight of the aircraft, thereby minimizing periodic impacts and frictional losses at gear meshing points. This invention achieves a higher flapping frequency and amplitude under the same power input.

[0050] This invention shortens the drivetrain and improves handling response quality: Because this invention integrates the flapping wing switching and flapping wing synchronization functions into a compact crank-rocker system, it reduces independent intermediate transmission and attitude adjustment links. The motion is transmitted from the drive source to the biomimetic wing skeleton of this invention through fewer intermediate links, resulting in less accumulated transmission backlash. This allows the invention to respond more directly and instantly when the flapping frequency or amplitude command changes. Consequently, it significantly reduces the lag and overshoot from control input to actual flight attitude change, enhancing the operator's ability to make precise, smooth, and real-time adjustments, enabling the aircraft to execute more complex trajectories and maneuvers.

[0051] Alternatives to flapping-wing synchronous drive: ①Dual-motor independent drive plus electronic synchronization control: This design uses two independent motors to drive the left and right bionic wings respectively, and achieves motion synchronization through sensor feedback and closed-loop control algorithms.

[0052] One publicly disclosed technical solution involves using a three-axis Hall effect sensor to collect real-time position information of the left and right flapping wing mechanisms. A microcontroller reads magnetic field strength data via an SPI bus, obtains the flapping wing position, and independently adjusts two PWM signals to control the speed of the left and right motors, thus achieving phase-difference flapping of the left and right wings at the same frequency. Another study uses dual servos to replace the traditional motor and gear transmission method, independently controlling the left and right wings. Controllable quantities include flapping amplitude, flapping frequency, and initial position to achieve various flight attitudes. A biomimetic butterfly project at a university also uses independent drive of left and right dual motors with a three-stage reduction gearbox and integrates an AS5600 magnetic encoder to achieve closed-loop feedback.

[0053] ② Single-crank driven double-crank double-rocker mechanism: Some existing butterfly-inspired flapping-wing aircraft employ a dual-crank, dual-rocker symmetrical flapping-wing drive mechanism, using a planar four-bar linkage to achieve symmetrical flapping of the left and right wings. The USTButterfly uses this type of design, has a wingspan of 50cm, weighs 50g, and can achieve 5 minutes of free and controllable flight.

[0054] Alternative solutions for the wing-standing / wing-folding function: ① Self-locking wing retraction and extension mechanism: A university has disclosed a self-locking wing-folding and spreading mechanism for a foldable flapping-wing micro-aircraft, the principle of which differs significantly from that of this invention. This solution uses a micro servo motor to control the wing-folding and spreading actions.

[0055] The main difference between this solution and the present invention is that this solution adds a complete wing-folding mechanism independently in addition to the normal flapping wing mechanism, including a dedicated micro motor, gear transmission chain and other components.

[0056] ② Foldable wing mechanism: A university has proposed a foldable biomimetic flapping-wing aircraft. Symmetrical wing-folding mechanisms are arranged on both sides of the telescopic component, including connecting rods, transmission rods, guide columns, and a four-bar folding mechanism. This allows the wings to be folded into the fuselage to protect them and improve space utilization. This design focuses on spatial folding during ground storage, rather than aerodynamic attitude switching during flight, which differs from the wing-standing function of this invention in its application scenarios.

[0057] ③ Utilizing inflation and deflation to drive the deployment and retraction of the wing membrane: Another approach uses a micro-pump to control the air content of the air column on the flapping wing membrane to achieve flapping wing deployment and retraction. During flight, the air column inflates to deploy the flapping wing, and after flight, the air column is deflated to retract it under the action of elastic force. This approach is suitable for folding requirements at specific scales, but it may not be as good as the mechanical locking approach of this invention in terms of response speed and control precision during real-time flight attitude switching.

[0058] Alternatives to yaw steering control: ① Aerodynamic differential steering: One approach controls the pitch motion of the wings relative to the incoming airflow during flapping, actively controlling the amplitude of this motion to generate aerodynamic differences between the two sides, thus replacing the rudder to change course. This approach directly acts on the lifting surface itself, eliminating the need for a rudder structure. Another approach achieves differential steering by changing the flapping amplitude difference between the left and right bionic wings, with a turning radius of less than 1.5 meters. This invention uses a central rudder combined with downwash airflow, resulting in a more direct structural implementation and a clearer decoupling between the generation and control of the steering torque.

[0059] In summary, the core of this invention integrates the two functions of flapping wing synchronization and upright wing switching into a variable angle crank gear mechanism. This integrated configuration constitutes the essential feature that distinguishes this technical solution from all alternative paths in terms of lightweight level and functional density.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A variable-angle crank-rocker adaptive biomimetic butterfly flight mechanism, characterized in that, It includes a symmetrically arranged bionic forewing (1) and a symmetrically arranged bionic rearwing (2). The symmetrically arranged bionic forewing (1) is connected by a variable angle crank rocker assembly (3), and the symmetrically arranged bionic rearwing (2) is connected by a variable angle crank rocker assembly (3). The variable angle crank rocker assembly (3) of the bionic forewing (1) and the variable angle crank rocker assembly (3) of the bionic rearwing (2) are connected by a stabilizing shaft mechanism. The variable angle crank rocker assembly (3) includes a frame (4), on which a symmetrical synchronous meshing mechanism is provided, and on both sides of the frame (4) a symmetrical crank connecting rod mechanism is provided, and the symmetrical crank connecting rod mechanism is connected to the symmetrical synchronous meshing mechanism.

2. The variable-angle crank-rocker adaptive bionic butterfly flight mechanism according to claim 1, characterized in that, The symmetrical synchronous meshing mechanism includes rocker arm 1 (5) and rocker arm 2 (6) symmetrically arranged on the frame (4). One end of rocker arm 1 (5) and one end of rocker arm 2 (6) are respectively hinged to the frame (4). The other end of rocker arm 1 (5) is connected to the bionic forewing (1) or the bionic rear wing (2). The other end of rocker arm 2 (6) is connected to the bionic forewing (1) or the bionic rear wing (2).

3. The variable-angle crank-rocker adaptive bionic butterfly flight mechanism according to claim 2, characterized in that, The first rocker arm (5) and the second rocker arm (6) are connected by tooth meshing and move synchronously.

4. The variable-angle crank-rocker adaptive bionic butterfly flight mechanism according to claim 3, characterized in that, The symmetrical crank-connecting rod mechanism includes a crank one (7) and a crank two (8) arranged symmetrically. A drive structure one (9) and a drive structure two (10) are symmetrically arranged on the frame (4). The output end of the drive structure one (9) is connected to the center of the crank one (7), and the output end of the drive structure two (10) is connected to the center of the crank two (8).

5. The variable-angle crank-rocker adaptive bionic butterfly flight mechanism according to claim 4, characterized in that, One end of crank one (7) is hinged to one end of vertical wing rod one (11), the other end of vertical wing rod one (11) is hinged to one end of connecting rod one (13), one end of crank two (8) is hinged to one end of vertical wing rod two (12), the other end of vertical wing rod two (12) is hinged to one end of connecting rod two (14), and vertical wing rod one (11) and vertical wing rod two (12) are symmetrically arranged; The end of connecting rod 1 (13) away from the first vertical wing rod (11) is hinged to the end of rocker arm 1 (5) away from the tooth engagement. The end of connecting rod 2 (14) away from the second vertical wing rod (12) is hinged to the end of rocker arm 2 (6) away from the tooth engagement. Connecting rod 1 (13) and connecting rod 2 (14) are symmetrically arranged.

6. The variable-angle crank-rocker adaptive bionic butterfly flight mechanism according to claim 5, characterized in that, A limiting protrusion (15) is provided at one end of crank one (7) near the hinge point with vertical wing rod one (11) and at one end of crank two (8) near the hinge point with vertical wing rod two (12). A limiting block (16) adapted to the limiting protrusion (15) is provided on vertical wing rod one (11) and vertical wing rod two (12). A limiting platform 1 (17) is provided at one end of crank 1 (7) away from the hinge point of crank 2 (8) and crank 2 (8) away from the hinge point of crank 2 (12). A limiting platform 2 (18) adapted to the limiting platform 1 (17) is provided on crank 1 (11) and crank 2 (12).

7. The variable-angle crank-rocker adaptive bionic butterfly flight mechanism according to claim 6, characterized in that, A protective plate (19) is provided on the side of the rocker arm 1 (5) and rocker arm 2 (6) away from the frame (4), and the rocker arm 1 (5) and rocker arm 2 (6) are located between the protective plate (19) and the frame (4).

8. The variable-angle crank-rocker adaptive bionic butterfly flight mechanism according to claim 7, characterized in that, The stabilizing axis mechanism includes a connecting shaft (20) and a connecting rod (21). The connecting shaft (20) passes through the upper end of the protective plate (19) at the bionic forewing (1) and the upper end of the frame (4) in sequence, and then passes through the upper end of the protective plate (19) at the bionic rear wing (2) and the upper end of the frame (4) in sequence. The connecting rod (21) passes through the lower end of the protective plate (19) at the bionic forewing (1) and the lower end of the frame (4) in sequence, and then passes through the lower end of the protective plate (19) at the bionic rear wing (2) and the lower end of the frame (4) in sequence.

9. The variable-angle crank-rocker adaptive bionic butterfly flight mechanism according to claim 8, characterized in that, A steering servo (22) is provided on the connecting rod (21), and the output end of the steering servo (22) is connected to the outer casing of the battery (23).

10. The driving method for a variable-angle crank-rocker adaptive bionic butterfly flight mechanism according to claim 9, characterized in that, Including normal flapping-wing flight mode and upright-wing flight mode; In normal flapping flight mode, the output end of drive structure one (9) drives crank one (7) to rotate counterclockwise, and the output end of drive structure two (10) drives crank two (8) to rotate clockwise. Crank one (7) is fixed to the vertical wing rod one (11), and crank two (8) is fixed to the vertical wing rod two (12). The output ends of drive structure one (9) and drive structure two (10) drive crank one (7) and crank two (8) to rotate synchronously. Crank one (7) and vertical wing rod one (11) drive connecting rod one (13) to swing back and forth. Crank two (8) and vertical wing rod two (12) drive connecting rod two (14) to swing back and forth. The swinging of connecting rod one (13) and connecting rod two (14) drives rocker one (5) and rocker two (6) to swing back and forth, thereby driving the symmetrically arranged bionic forewing (1) to swing back and forth and the symmetrically arranged bionic rearwing (2) to swing back and forth. In the upright wing flight mode, the output end of drive structure one (9) drives crank one (7) to rotate clockwise, and the output end of drive structure two (10) drives crank two (8) to rotate counterclockwise. The fixation between crank one (7) and upright wing rod one (11) is released, and the fixation between crank two (8) and upright wing rod two (12) is released. The output ends of drive structure one (9) and drive structure two (10) respectively drive crank one (7) and crank two (8) to rotate synchronously with fine adjustment. Crank one (7) pushes connecting rod one (13) to rotate through upright wing rod one (11), and crank two (8) pushes connecting rod two (14) to rotate through upright wing rod two (12). Connecting rod one (13) and connecting rod two (14) respectively push rocker one (5) and rocker two (6) to swing synchronously.

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