Dual-motor bionic butterfly flapping wing device

Abstract

The invention relates to the technical field of bionic flapping wings, and particularly discloses a double-motor bionic butterfly flapping wing device which comprises a rack and flapping wing mechanisms symmetrically arranged on the two sides of the rack. The flapping wing mechanism comprises a driving motor, a self-eccentric crank sliding block assembly and a flapping wing; the driving motor is fixed to the end of the rack, the lower end of the flapping wing is hinged to the lower end of the rack, one end of the self-eccentric slider-crank assembly is connected with the power output end of the driving motor, and the other end of the self-eccentric slider-crank assembly is slidably connected with the flapping wing and pushes the flapping wing to rotate. A dual-motor driving structure based on a self-eccentric quick-return mechanism is adopted, and the eccentric sliding block and the sliding groove are introduced for guiding, so that asymmetric rhythm control of'fast upward and slow downward 'is realized, an asymmetric flapping mode in butterfly flight is more truly restored, and the bionic authenticity and the motion coordination of the mechanism are remarkably enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of bionic flapping wing technology, and particularly relates to a double-motor bionic butterfly flapping wing device. BACKGROUND

[0002] Flapping wing vehicles have broad application prospects in the fields of micro air robots, environmental monitoring, military reconnaissance and pollen transmission due to their high maneuverability, low radar cross section and good bionic characteristics. Among them, the flight system taking butterflies and other insects as the bionic object has become a hot research direction of bio-inspired flight control in recent years due to its elegant flapping trajectory and unique power structure. However, the current bionic butterfly flapping mechanism still has obvious deficiencies in transmission efficiency, structural lightweighting and rapid turning motion mechanism, and it is difficult to effectively restore the dynamic characteristics of the real butterfly asymmetric flapping. These problems not only affect the flight performance of the mechanism, but also restrict the expansion of the mechanism in practical applications.

[0003] In the traditional design, the flapping wing mechanism is driven by a single motor and a symmetrical linkage mechanism to complete the periodic up-and-down flapping. However, this structure often cannot effectively simulate the asymmetric flapping characteristics of the butterfly in real flight, that is, the up-stroke is fast and the down-stroke is slow, resulting in a decrease in air dynamic efficiency and unstable flight attitude control. However, the contradiction between structural rigidity and lightweighting is still a key factor limiting the performance improvement of the mechanism.

[0004] Therefore, a double-motor bionic butterfly flapping wing device becomes a problem to be solved. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a double-motor bionic butterfly flapping wing device, which adopts a double-motor independent driving and asymmetric motion rhythm control strategy, introduces a self-eccentric slider track constraint, realizes a rapid turning motion characteristic, that is, the up-stroke time is less than the down-stroke time, and thus more truly restores the asymmetric flapping mode in butterfly flight. The device simplifies the transmission structure, effectively improves the motion controllability and bionic stability, and realizes a more optimal balance between structural rigidity and lightweighting.

[0006] To solve the above technical problems, the technical scheme provided by the present application is as follows: a double-motor bionic butterfly flapping wing device, comprising a rack and flapping wing mechanisms symmetrically arranged on both sides of the rack.

[0007] The flapping wing mechanism comprises a driving motor, a self-eccentric crank slider assembly and a flapping wing.

[0008] The driving motor is fixed at the end of the rack, the lower end of the flapping wing is hinged to the lower end of the rack, one end of the self-eccentric crank slider assembly is connected to the power output end of the driving motor, and the other end is slidingly connected to the flapping wing and pushes the flapping wing to rotate.

[0009] Further, the self-biased crank slider assembly comprises a driving rod and a slider, one end of the driving rod is connected with the power output end of the driving motor and is driven thereby, and the slider is fixed at the other end of the driving rod and is in sliding connection with the flapping wing.

[0010] Further, a guide sliding groove is arranged on the flapping wing and extends along the length direction of the flapping wing, and the slider is inserted into the guide sliding groove and drives the flapping wing to rotate by sliding.

[0011] Further, a mounting portion is arranged in the middle of the rack, and the mounting portion is used for connecting other devices.

[0012] Compared with the prior art, the present application has the following advantages:

[0013] The present application adopts a double-motor driving structure based on a self-biased quick-return mechanism, introduces an eccentric slider and a sliding groove guide, realizes the asymmetric beat control of "fast up and slow down", more truly restores the asymmetric flapping mode in the flight of a butterfly, and significantly enhances the bionic authenticity and motion coordination of the mechanism.

[0014] The whole power transmission structure is simple, continuous and stable, effectively avoids the energy loss and control uncertainty caused by multi-stage transmission, and improves the transmission efficiency of the system.

[0015] The present application has good scalability and control flexibility, by adjusting the length of the connecting rod and the sliding groove path parameters, different wing types, frequencies or flapping amplitudes can be quickly adapted without changing the overall topological structure, facilitating the expansion of various bionic application scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a structural schematic view of a double-motor bionic butterfly flapping device.

[0017] Figure 2 is a front view of a double-motor bionic butterfly flapping device.

[0018] Figure 3 is a kinematics modeling principle diagram of a double-motor bionic butterfly flapping device.

[0019] Figure 4 is a space motion trajectory curve diagram of a double-motor bionic butterfly flapping device in a simulation process.

[0020] Figure 5 is a speed response characteristic curve diagram of a simulation structure analysis.

[0021] Figure 6 is an acceleration characteristic curve diagram of a simulation structure analysis.

[0022] Figure 7 is a flapping displacement positive interval fitting curve diagram of the simulation model.

[0023] Figure 8 is a flapping displacement positive interval fitting curve diagram of the theoretical model.

[0024] As shown in the figure: 1, rack, 2, drive motor, 3, flapping wing, 4, drive rod, 5, sliding block, 6, guide chute, 7, mounting portion. DETAILED DESCRIPTION

[0025] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "inner", "outer", "vertical", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0026] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0027] The present application will be further described in detail below with reference to the accompanying drawings.

[0028] In combination with the accompanying drawings Figures 1-8 The present application will be described in detail.

[0029] A dual-motor bionic butterfly flapping wing device mainly comprises a rack 1 and flapping wing mechanisms symmetrically arranged on both sides of the rack 1.

[0030] The rack 1 serves as a support structure of the entire device and provides a stable mounting basis for the flapping wing mechanism. The rack 1 is provided with a mounting portion 7 in the middle, which can be used to connect other devices, facilitating the functional expansion and integration of the device according to different application requirements and the assembly connection with other devices.

[0031] The flapping wing mechanism is the core part of the present application, and each side of the flapping wing mechanism comprises a drive motor 2, a self-eccentric crank slider 5 assembly and a flapping wing 3.

[0032] The driving motor 2 is fixed at the end of the frame 1, and serves as a power source for the flapping wing 3. The two driving motors are symmetrically arranged, which can provide independent and stable power output for the flapping wings 3 on both sides, and is beneficial to realize more accurate flapping motion control and improve the flight stability of the device.

[0033] The self-eccentric crank slider 5 assembly includes a driving rod 4 and a slider 5. One end of the driving rod 4 is connected with the power output end of the driving motor 2, and rotates under the driving of the driving motor 2. The slider 5 is fixed at the other end of the driving rod 4 and is in sliding connection with the flapping wing 3. The self-eccentric crank slider 5 assembly ingeniously converts the rotary motion of the driving motor 2 into the reciprocating linear motion of the slider 5, and then drives the flapping wing 3 to realize the flapping action.

[0034] The lower end of the flapping wing 3 is hinged with the lower end of the frame 1, so that the flapping wing 3 can rotate around the hinge point. The flapping wing 3 is provided with a guide sliding groove 6 extending along the length direction of the flapping wing 3. The slider 5 is inserted into the guide sliding groove 6. When the driving rod 4 is rotated under the driving of the driving motor 2, the slider 5 slides in the guide sliding groove 6, thereby driving the flapping wing 3 to rotate around the hinge point and realizing the flapping action. The structure design makes the movement of the flapping wing 3 more smooth and natural, can better simulate the flapping trajectory of the butterfly wing, and improves the bionic effect of the device.

[0035] The specific implementation process of the bionic butterfly flapping device with double motors is as follows:

[0036] The present application aims to realize asymmetric beat control, simulate the flapping mode of "fast up and slow down" in the process of butterfly flight, and balance between lightweight structure and driving efficiency.

[0037] The driving part is independently controlled by two DC motors on the left and right sides. Each structure converts the rotary motion of the motor into asymmetric linear reciprocating motion through a self-eccentric crank slider 5 assembly. By adjusting the size, the quick return ratio can be flexibly adjusted to realize the "quick return motion characteristic" of the upper stroke time being less than the lower stroke time.

[0038] The output end of the self-eccentric crank slider 5 assembly transmission is the symmetrically arranged double-sided wing, the root of which is hinged with the lower end of the frame 1, and the periodic bionic motion of the wing lifting and flapping is completed through the driving of the crank slider 5. The crank length and eccentric distance together determine the flapping angle amplitude and beat period of the device, so that the system has sufficient motion stroke under the premise of compact structure.

[0039] The application has good scalability and control flexibility. By adjusting the size of the eccentric wheel, the length of the connecting rod and the slide groove path parameters, different wing types, frequencies or flapping amplitudes can be quickly adapted without changing the overall topology, facilitating subsequent experimental verification and expansion of various bionic application scenarios.

[0040] The operation principle of the application is as follows:

[0041] The application adopts a left-right symmetrical layout, and two groups of self-eccentric crank slider assemblies are used as power input cores to realize bionic flapping wing movement with asymmetric beats. Figure 3 The kinematic modeling principle diagram of the device shows the complete structural path of driving, transmission and output.

[0042] The left side of the device takes point A as the driving center, and the driving motor drives the driving rod to rotate around point A at an angular velocity ω. The slider C moves along the preset track to push the flapping wing BC to realize the lifting and flapping action. The right side structure is symmetrical about the origin O, and the working principle is completely consistent.

[0043] The slider C is connected with the driving rod, and an approximately elliptical track is formed during the rotation of the driving rod, causing the motion time of the slider to be asymmetric in the return (upstroke) and working (downstroke) processes, thereby embodying the quick-return motion effect. The eccentric distance is determined by the distance between the center of the driving rod and the driving motor connection and the flapping wing, which is marked as r.

[0044] The connecting point B-C is an output connecting rod, one end of which is hinged with the slider C, and the other end is connected with the wing, which is used to drive the wing to complete periodic bionic swing. Assuming that AB is a fixed connecting rod with a length of L and BC is an output connecting rod with a length of r, according to the geometric relationship of the mechanism, the length of the connecting rod BC at any time t can be derived by the cosine theorem as follows:

[0045]

[0046] Further, the instantaneous flapping angle α of the wing can be obtained, which is the included angle of the connecting rod BC relative to the reference line, and the calculation formula is as follows:

[0047]

[0048] The angle periodically changes in each cycle, which is the main power output characteristic of the bionic flapping wing.

[0049] According to the associated velocity decomposition method, the velocity of the slider is composed of two parts: one is the tangential velocity V r caused by the driving rod, which is perpendicular to the connecting line OA; the other is the constraint velocity V e in the slide groove direction. According to the velocity synthesis principle, the velocity of the end C of the slider is:

[0050] V a = V e + V r (3)

[0051] In order to further obtain the connecting rod angular velocity, the derivative of the flapping angle formula (2) is taken, and the following formula is obtained:

[0052]

[0053] By combining (3) and (4), the component expression of the slider velocity is obtained:

[0054]

[0055] Wherein, i represents the unit vector in the x direction, and j represents the unit vector in the y direction; the velocity expression reflects the change rule of the movement speed of the slider at different positions, and directly affects the frequency and beat structure of the flapping wing.

[0056] Another significant motion characteristic of the present application is the quick return effect. Due to the asymmetry of the driving rod track, the time experienced by the slider in the upstroke (return stroke) is significantly less than that in the downstroke (working stroke), thereby realizing the asymmetry of the flapping wing beat, and the quick return ratio is defined as:

[0057]

[0058] This feature makes the wing slowly apply force in the downstroke phase and quickly return in the upstroke phase, which conforms to the aerodynamic characteristics of the real butterfly in flight, that is, using the downstroke to accelerate and the upstroke to reduce drag.

[0059] In summary, the present application not only realizes continuous control of the angle of the bionic flapping wing, but also has adjustable beat ratio, driving rate and output track range, and the overall structure is compact and the motion is stable, thereby providing a theoretical basis and geometric support for subsequent motion simulation and performance analysis.

[0060] The simulation verification of the present application is as follows:

[0061] 1. Simulation modeling and parameter setting

[0062] A complete three-dimensional multi-body dynamics simulation model is constructed based on the ADAMS software platform. The simulation modeling strictly follows the actual assembly logic and power transmission path of the mechanism, so as to ensure that the motion process is consistent with the physical structure.

[0063] Firstly, the working coordinate system is set: taking the center of the rack as the origin, the Y axis is coincided with the direction of the main shaft of the rack, and the Z axis is vertically upward and perpendicular to the ground. The coordinate system serves as a unified reference for subsequent extraction of displacement, velocity and acceleration.

[0064] In the connection setting, the rack is first fixedly constrained with the ground in the simulation model as the reference datum of the whole system. Then, the right driving rod is connected with the rack through a rotating pair to realize the rotational freedom; a line-line constraint is applied between the driving rod end pin and the sliding slot on the swing rod to limit the sliding block to slide in the slot only; a second rotating pair is applied between the swing rod and the rack to complete the periodic swing. The left structure is completely mirror-symmetrically arranged to form a double-wing synchronous driving system. Then, the friction force is increased at the connection to make the simulation model closer to the actual model.

[0065] To accurately extract the flapping angle and response characteristics, local coordinate systems are defined at the ends of the left and right swing rods as the observation datum for angle extraction and motion curve output. In the power input aspect, constant angular velocities ω = 7200 deg / s (i.e. 1200 rpm) are applied to the left and right driving rods respectively to simulate the actual motor working state. The simulation duration covers two complete motion periods, and the time step is set to 0.0001 s to ensure that the output data have sufficient time domain precision and stability.

[0066] 2. Simulation result analysis

[0067] After the multi-body dynamics simulation model is completed, the present application comprehensively analyzes the dynamics behavior of the mechanism from four aspects of end point space motion characteristics, speed response, acceleration change and output angle consistency.

[0068] (1) Space motion trajectory and beat characteristics

[0069] From the three-dimensional displacement data extracted from the simulation, the C point forms a closed elliptical trajectory in the X-Y plane, which mainly reciprocates along the X axis direction, and the Y direction shows a typical asymmetric flapping path. The simulation data show that the maximum displacement in the Y direction is +30.0324 mm, and the minimum displacement is –2.953 mm, corresponding to a total swing amplitude of about 32.9854 mm, which constitutes a complete flapping path. The upstroke displacement amplitude (from the lowest point to the highest point) is much larger than the downstroke process, forming a time-space double asymmetric beat.

[0070] In the X direction, the displacement range of the C point is –20.7664 mm to +16.4325 mm, and the total fluctuation value is more than 37.1989 mm, reflecting that the driving system provides sufficient transmission stroke in the whole period. The maximum offset in the Z direction is 1.1546 x 10 -12 mm, although the change is not as significant as the Y direction, but the existence of nonlinear disturbance can still be observed, which is mainly caused by the non-ideal contact of the sliding slot and the small amount of separation in the coupling process of the swing pair. The space motion trajectory curve of the device is shown in Figure 4 .

[0071] (2) Speed response and beat structure

[0072] The velocity analysis results show that the mechanism exhibits good periodic response in both X and Y directions. The X-direction velocity data also show symmetrical swing characteristics, with a maximum value of +15104.2 mm / s and a minimum value of -1572.39 mm / s, which are basically symmetrical, indicating that the main drive path transmission efficiency is good and there is no obvious polarization. The maximum Y-direction velocity is +13816.9 mm / s and the minimum is -1517.44 mm / s, which indicates that the mechanism exhibits typical quick-return motion characteristics, i.e., the asymmetric velocity rhythm of "fast up and slow down" during the simulation. The velocity peaks are mainly concentrated at the swing reversal time, and the mechanism realizes instantaneous large speed transition through the eccentric slider structure, which is consistent with the rapid lifting behavior in the natural flight of butterflies.

[0073] To quantify the rhythm difference, the quick-return ratio Q is introduced to represent the ratio of the time consumed by the upstroke and the downstroke:

[0074]

[0075] where T downstroke is the downstroke duration and T upstroke is the upstroke duration. According to the simulation data, the extracted rhythm time points are calculated, and the obtained quick-return ratio is significantly greater than 1, which is consistent with the bionic rhythm law of "long power output period and short return period" in biological flapping motion mode. The velocity response characteristic curve of the device is shown in FIG. 8. Figure 5

[0076] (3) Acceleration transient characteristics

[0077] The acceleration data further reflects the dynamic load characteristics of the mechanism under high-frequency driving. The maximum X-direction acceleration is +0.689x10 7 mm / s 2 , which also presents stable and high-intensity alternating characteristics, ensuring that the system has good periodic closed-loop driving capability. The maximum Y-direction acceleration is +1.1641x10 7 mm / s 2 , the minimum is -0.62714x10 7 mm / s 2 , and there is more than 2 times difference between the two extreme values, indicating that the response during the rapid pulling process of the wing from the lowest point has strong impact. The maximum Z-direction acceleration is only 2.1796x10 -7 mm / s 2 , which can be considered as no significant vertical inertia fluctuation occurs during the simulation.

[0078] ​Since the driving motion has discontinuous angular velocity input, its acceleration response presents a sharp pulse characteristic, which accords with the dynamics law of "burst acceleration-instantaneous reversal-force pulse release" of the bionic flapping mechanism in actual work. The acceleration characteristic curve of the mechanism is shown in the accompanying Figure 6

[0079] (4) Flapping angle consistency and error evaluation

[0080] To further verify the motion rationality of the mechanism from the angle dimension, the present application calculates the mechanism swing angle α based on the Y(t) data output by the simulation, using the inverse formula to satisfy:

[0081]

[0082] Wherein, Y(t) is the Y coordinate of each time of C point extracted in the simulation; L is the rack length; r is the crank length; and α(t) is the output angle.

[0083] The maximum value of the flapping angle is +76.5488°, the minimum value is -36.5488°, and the total amplitude is 113.0976°. The flapping displacement positive interval fitting curve of the simulation model is shown in the accompanying Figure 7

[0084] The maximum value of the flapping angle is +76.55°, the minimum value is -36.55°, and the total amplitude is 113.10°. The flapping displacement positive interval fitting curve of the theoretical model is shown in the accompanying Figure 8

[0085] Accordingly, the relative error between the simulation and the theory is calculated as follows:

[0086]

[0087] The result shows that the established simulation model can still realize good periodic motion under the complex conditions of structural constraint and friction disturbance, and the output angle response is highly consistent with the theoretical design value, which further verifies the correctness of the modeling method of the present application and the reliability of the kinematics analysis model.

[0088] The above describes the present application and its embodiments, which are not restrictive, and the shown in the accompanying drawings is only one of the embodiments of the present application, and the actual structure is not limited thereto. In summary, if the ordinary skilled in the art is inspired thereby, without departing from the purpose of the present application, without creative design, similar structure and embodiments of the technical solutions are not creative design, which shall belong to the protection scope of the present application.​​​

Claims

1. A dual-motor bionic butterfly flapping device, characterized by: It comprises a frame (1) and flapping wing mechanisms symmetrically arranged on both sides of the frame (1); The flapping wing mechanism comprises a driving motor (2), a self-eccentric crank slider (5) assembly and flapping wings (3); The driving motor (2) is fixed to the end of the frame (1); the lower end of the flapping wing (3) is hinged to the lower end of the frame (1); one end of the self-eccentric crank slider (5) component is connected to the power output end of the driving motor (2); the other end is slidably connected to the flapping wing (3) and drives it to rotate.

2. The dual-motor bionic butterfly flapping device according to claim 1, characterized in that: The self-eccentric crank slider (5) assembly comprises a driving rod (4) and a slider (5); one end of the driving rod (4) is connected to the power output end of the driving motor (2) and is driven thereby; the slider (5) is fixed to the other end of the driving rod (4) and is slidably connected to the flapping wing (3).

3. The dual-motor bionic butterfly flapping device according to claim 2, characterized in that: The flapping wing (3) is provided with a guide slot (6), which extends along the length direction of the flapping wing (3). The slider (5) is inserted into the guide slot (6) and slides along the guide slot to drive the flapping wing (3) to rotate.

4. The dual-motor bionic butterfly flapping device according to claim 3, characterized in that: A mounting portion (7) is provided in the middle of the frame (1), and the mounting portion (7) is used for externally connecting other devices.

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