Bionic butterfly flapping wing aircraft with variable gravity center steering device and variable wing area

Abstract

The invention relates to the technical field of bionic aircrafts, in particular to a bionic butterfly flapping wing aircraft with a variable gravity center steering device and variable wing area, which comprises a fuselage main body, a control unit, and a variable wing area mechanism and a variable gravity center steering device which are respectively connected with the control unit, the variable wing area mechanism is mounted on a wing connecting part of the fuselage main body and is used for driving a front wing and a rear wing on the same side of the aircraft to generate relative periodic or commanding angle change, so that the effective windward area of the wing on one side is dynamically changed; the variable gravity center steering device is mounted in the central area of the aircraft main body and used for driving a centrally-configured counterweight assembly to transversely move along the aircraft main body so as to actively and controllably change the horizontal position of the gravity center of the aircraft; wherein the control unit is configured to optimize the flight lift force or assist steering by controlling the variable wing area mechanism, and to realize the main steering action of the aircraft by controlling the variable gravity center steering device.

Description

Technical Field

[0001] This invention relates to the field of biomimetic aircraft technology, and in particular to a biomimetic butterfly flapping-wing aircraft with a variable center of gravity steering device and variable wing area. Background Technology

[0002] Ornithopter is a novel type of biomimetic aircraft that generates upward lift and forward thrust by mimicking the flapping of wings of birds or insects such as butterflies. Compared to fixed-wing and rotary-wing aircraft, ornithopter has lower noise, lower energy consumption, and higher biomimicry, making it a promising candidate for applications in terrain exploration, disaster relief, and biological research.

[0003] Ornithoptering aircraft are sensitive to their own weight and must find ways to increase lift while controlling their own weight. Some butterflies in nature have two relatively separate wing halves on each side. When flapping downwards, they open both wing halves completely to maximize their frontal area; when flapping upwards, they use muscles to bring the wing halves together, increasing the overlap area between the wings to reduce the effective frontal area. This modal change in wing area with flapping increases the total lift over the period.

[0004] Regarding steering in flapping-wing aircraft, existing research is divided into tailed and tailless designs. Tailed designs are commonly used in bird-inspired flapping-wing aircraft, requiring a large tail area and a heavy actuator, making them unsuitable for butterfly-inspired flapping-wing aircraft. Tailless designs generally rely on differential adjustment of lift on both sides to achieve steering. Although this is easier to implement in servo-driven flapping-wing aircraft, it results in lift loss and a limited turning radius, necessitating the development of other steering modes and mechanisms to assist in directional control. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a biomimetic butterfly flapping-wing aircraft with a variable center of gravity steering device and variable wing area, comprising: The fuselage body, the control unit, and the variable wing area mechanism and variable center of gravity steering device respectively connected to the control unit; The variable wing area mechanism is installed at the wing connection part of the fuselage body and is used to drive the front wing and rear wing on the same side of the aircraft to produce relative periodic or commanded angle changes, thereby dynamically changing the effective windward area of ​​a single wing. The variable center of gravity steering device is installed in the central area of ​​the fuselage body and is used to drive a centrally configured counterweight assembly to move laterally along the fuselage body in order to actively and controllably change the horizontal position of the aircraft's center of gravity. The control unit is configured to optimize flight lift or auxiliary steering by controlling the variable wing area mechanism, and to realize the main steering action of the aircraft by controlling the variable center of gravity steering device.

[0006] Furthermore, the variable wing area mechanism includes a first drive unit, a first transmission assembly, and a wing connecting plate assembly; The wing connecting plate assembly includes a first wing connecting plate and a second wing connecting plate that are rotatably connected to each other. The first drive unit is fixed to the first wing connecting plate; The first transmission assembly connects the output end of the first drive unit to the second wing connecting plate, and is used to convert the output motion of the first drive unit into the rotation of the second wing connecting plate.

[0007] Furthermore, the first drive unit is a linear servo, the first wing connecting plate is a butterfly forewing connecting plate, and the second wing connecting plate is a butterfly rearwing connecting plate; The first transmission assembly includes a slot disposed on the connecting plate of the butterfly rear wing and a rocker arm disposed on the linear servo, the end of the rocker arm of the linear servo extending into the slot.

[0008] Furthermore, the variable wing area mechanism also includes a limiting block, which is disposed on the butterfly front wing connecting plate and is used to limit the rotation limit position of the butterfly rear wing connecting plate.

[0009] Furthermore, the variable center of gravity steering device includes a second drive unit, a second transmission assembly, and the counterweight assembly, all mounted on the fuselage body. The counterweight assembly includes a battery mounting frame that is oscillatingly disposed at the rear of the main body of the fuselage and a battery disposed in the battery mounting frame; The second transmission component is connected to the output end of the second drive unit and is used to drive the counterweight component to reciprocate laterally along the main body of the machine.

[0010] Furthermore, the second drive unit is a rotary servo motor; The second transmission assembly includes a take-up and release reel, a traction line, and a flexible guide. The take-up and release reel is fixed to the output shaft of the rotating servo motor; One end of each of the two traction lines is connected to the end of the elastic guide, and the other end is wound around the take-up and release reel in the opposite direction; The elastic guide is a flexible carbon rod, one end of which is fixed to the main body of the machine, and the other end passes through the battery mounting frame and is connected to the two traction lines.

[0011] Furthermore, the two traction lines are connected to the end of the flexible carbon rod via a hook-and-loop bar; the two ends of the hook-and-loop bar are provided with loop-shaped structures for fixing the two traction lines respectively, and the middle section is provided with a through hole for fixing the end of the flexible carbon rod.

[0012] Furthermore, the control unit is configured to: control the variable wing area mechanism to maximize the effective windward area of ​​the wing during the descent phase of the aircraft, and control it to minimize the effective windward area of ​​the wing during the ascent phase.

[0013] Furthermore, the control unit is configured to: upon receiving a steering command, differentially control the variable wing area mechanisms on the left and right sides, and / or control the variable center of gravity steering device to drive the counterweight assembly to shift laterally.

[0014] In the above scheme, for the variable wing area device, the butterfly-shaped flapping-wing aircraft can reduce downward drag by decreasing the effective wing's frontal area when flapping upwards and increase upward lift by increasing the effective wing's frontal area when flapping downwards, thus achieving a total lift increase within one cycle. Based on this, the control unit sends a pulse width modulation (PWM) command to the linear servo, and the rocker arm will move to the designated position according to the command. One of the butterfly wing connecting plates will rotate around the bearing, causing a change in the overlap area between the wings, thereby changing the effective frontal area of ​​the wing. Furthermore, it can be pointed out that the change in wing area can be asymmetrical, so slightly differentiating the target position of the linear servo on both wings can also simultaneously assist in completing the turning action. Obviously, when the flapping wing area is smaller and the flapping wing area is larger, the total lift within the cycle is greater; when the difference in the effective wing areas on both sides is greater, the turning effect is more obvious and the turning radius is smaller.

[0015] In the above scheme, for the variable center of gravity steering device, when the control unit receives a heading change command, it sends a pulse width modulation (PWM) command to the rotating servo, which in turn rotates the take-up and release spool. Because the spool rotates and the two sides of the thin line are wound in opposite directions within the spool, the flexible carbon rod passing through the battery mounting bracket will bend to one side, achieving a left-right adjustment of the fuselage's center of gravity. The fuselage will then tilt downwards to one side, achieving steering. The advantages of this approach are: the continuous bending degree of the flexible carbon rod allows for smooth and precise control of changes in the center of gravity distribution; the flexible carbon rod has natural flexibility, and the energy stored during bending can be released during the servo's return to the starting position (center of gravity back to center), assisting the servo in returning to its original neutral position and saving energy. It is easy to deduce that the further the center of gravity distribution deviates from the center, the more pronounced the turning effect and the smaller the turning radius.

[0016] Compared with the prior art, the beneficial effects of the present invention are: The biomimetic butterfly-shaped flapping-wing aircraft proposed in this invention features a variable wing area device and a variable center of gravity steering device. These devices improve lift from the perspective of aerodynamic generation, offering advantages such as light weight, simple structure, and ease of implementation, making them suitable for mounting on lightweight butterfly-shaped flapping-wing aircraft. The steering scheme, explored from the perspective of center of gravity distribution, offers advantages such as smooth control and energy saving. Furthermore, by rotating the orientation of the take-up and release reels by 90 degrees, the flapping motion of a real butterfly can be achieved, further enhancing the pitch stability and biomimetic degree of the butterfly-shaped flapping-wing aircraft. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a structural diagram of a biomimetic butterfly flapping-wing aircraft with a variable center of gravity steering device and variable wing area according to the present invention. Figure 2 for Figure 1 Bottom view of the variable wing area mechanism and variable center of gravity steering device; Figure 3 for Figure 1 Top view of the variable wing area mechanism and variable center of gravity steering device; Figure 4 Top view of the fuselage when the variable wing area mechanism is operating at the maximum wing area; Figure 5 A top view of the fuselage body when the variable wing area mechanism operates at its minimum wing area.

[0018] Figure Labels 1: Wings; 1a: Left forewing; 1b: Right forewing; 1c: Left hindwing; 1d: Right hindwing; 2: Main fuselage; 3: Variable wing area mechanism; 3a: Butterfly front wing connecting plate; 3a1: Limiting block; 3a2: Groove; 3b: Butterfly rear wing connecting plate; 3c: Linear servo; 3c1: Rocker arm; 4: Variable center of gravity steering device; 4a: Rotary servo motor; 4b: Reel / unload reel; 4c: Battery mounting frame; 4d: Battery; 4e: Flexible carbon rod; 4f: Cable retainer; 4g: Servo motor mounting base. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the 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 merely illustrative of the invention and are not intended to limit the invention.

[0020] To keep the drawings concise, only the parts relevant to the invention are shown schematically in each figure, and they do not represent the actual structure of the product. Furthermore, for ease of understanding, in some figures, only one of components with the same structure or function is shown schematically, or only one is labeled. In this document, "one" can mean not only "only one" but also "more than one".

[0021] First Embodiment Please see Figure 1-5 The technical solution of the biomimetic butterfly flapping-wing aircraft with a variable center of gravity steering device and variable wing area provided in this embodiment includes the following: As attached Figure 1 As shown, the structure of the present invention mainly includes a fuselage body 2 in the middle, variable wing area mechanisms 3 disposed on both sides of the fuselage body 2, a variable center of gravity steering device 4 disposed on the fuselage body 2, and a control unit for controlling the variable wing area mechanism 3 and the variable center of gravity steering device 4.

[0022] The variable wing area mechanism 3 includes a butterfly forewing connecting plate 3a and a butterfly rearwing connecting plate 3b, a linear servo 3c, a bearing (installed between the butterfly forewing connecting plate 3a and the butterfly rearwing connecting plate 3b, not shown in the figure), and a limit block 3a1. The power supply and other structures are common knowledge to those skilled in the art, so they will not be described in detail.

[0023] In practice, the left forewing 1a and the right forewing 1b of the wing 1 are respectively installed on the two butterfly forewing connecting plates 3a, and the left hindwing 1c and the right hindwing 1d of the wing 1 are respectively installed on the two butterfly hindwing connecting plates 3b.

[0024] In one embodiment of the present invention, a linear servo 3c is mounted in a butterfly-shaped flapping-wing connecting plate 3a. The linear servo 3c has a cuboid structure with a mounting hole at each of its four corners. The butterfly-shaped flapping-wing connecting plate 3a also has corresponding threaded holes at its lower part. A fixing screw of appropriate length and outer diameter can be passed through the servo mounting hole and screwed into the threaded hole of the butterfly-shaped flapping-wing connecting plate 3a to fix the linear servo 3c to the butterfly-shaped flapping-wing connecting plate 3a. In one embodiment of the present invention, the selected linear servo 3c weighs as little as 1.1g each, making it suitable for installation on a butterfly-shaped flapping-wing aircraft.

[0025] In one embodiment of the present invention, a rocker arm 3c1 is provided at the center of the edge of the linear servo 3c, and a groove 3a2 is provided on the butterfly rear wing connecting plate 3b. The rocker arm 3c1 is inserted into the groove 3a2 of the butterfly rear wing connecting plate 3b. The inner and outer sides of the bearing are respectively fixed between the two butterfly wing connecting plates. The limiting block 3a1 is installed on one of the butterfly wing connecting plates to limit the relative relationship between the two wings.

[0026] More specifically, the slot 3a2 of the butterfly rear wing connecting plate 3b is rectangular, and its centerline passes through the center of the bearing connecting the two butterfly wing connecting plates. When the rocker arm 3c1 of the linear servo 3c moves back and forth, the rocker arm 3c1 will touch the edge of the slot 3a2, and convert the linear motion of the rocker arm 3c1 of the linear servo 3c into the rotation of the rear wing of the flapping wing aircraft around the axis, thereby changing the overlap area of ​​the front and rear wings, and thus causing a change in the effective wing area.

[0027] The specific flight process for achieving lift enhancement through variable wing area is as follows: When a flapping-wing aircraft takes off, it should first perform a downward flapping stroke to gain lift and avoid falling. At this point, maximum lift is required, therefore, the effective windward flight area of ​​the wing must be maximized. The linear servo 3c described in this invention will first operate to its lower limit position and maintain it with power before flight, minimizing the overlap area between the rear wing and forewing and maximizing the effective windward area. During normal flight, the control unit will calculate the flapping frequency output by the navigation system and control the linear servo 3c to also reciprocate according to the wing flapping cycle via pulse width modulation (PWM) commands, thus ensuring that the wing area is maximized when both wings begin to flap (wing surfaces facing each other). Figure 4 When the wings begin to flap upwards, the wing area is at its smallest (wing surfaces facing each other as shown). Figure 5 This is to maximize the total lift during the cycle.

[0028] In one embodiment of the invention, the variable wing area device can also be used as a highly efficient steering device. Clearly, differentially changing the effective frontal area of ​​the two wings can create an imbalance in lift on both sides, with the side with the larger wing area generating greater lift and the side with the smaller wing area generating less lift. Therefore, the entire fuselage will tilt downwards towards the side with the smaller wing area, achieving a steering maneuver.

[0029] The variable center of gravity steering device 4 includes a rotary servo motor 4a, a servo motor bracket 4g, a take-up and release reel 4b, a thin line, a battery mounting frame 4c, a battery 4d, and a flexible carbon rod 4e.

[0030] In one embodiment of the present invention, a rotary servo motor 4a is installed in a servo motor bracket 4g on the main body 2, and a take-up and release spool 4b is fixed to the gear of the rotary servo motor 4a; a flexible carbon rod 4e passes through a battery mounting frame 4c, with one end fixed to the main body 2 and the other end fixed to a wire-fastening rod 4f; two thin lines are wound in opposite directions on the take-up and release spool 4b, and the ends of the lines are knotted and fixed in the groove on the side of the take-up and release spool 4b.

[0031] When the control unit receives the "change course" command, the rotary servo 4a will rotate. Because the winding directions of the thin lines on both sides are opposite, the rope length on one side will decrease and the rope length on the other side will increase, causing the flexible carbon rod 4e to deform towards the side with the shorter rope length. This causes the battery mounting frame 4c through which the flexible carbon rod 4e passes and the battery 4d within it to deviate from the center of the fuselage. Since the battery 4d has a large mass, the unbalanced horizontal distribution of the center of gravity will cause the main body of the fuselage 2 to sink towards the side tilted towards the center of gravity, thus achieving the corresponding steering action. Because the servo control has closed-loop feedback control characteristics, the control of the center of gravity change can be smooth and precise, enabling accurate adjustment of the turning radius.

[0032] In one embodiment of the present invention, after assembling the variable wing area mechanism 3 and the variable center of gravity steering device 4, the flapping wing servo is installed into the flapping wing servo bracket, the central carbon sheet of the fuselage body is inserted, and the variable wing area mechanism 3 and the variable center of gravity steering device 4 are installed. Finally, the four wings 1a, 1b, 1c and 1d are installed, and normal flight and turning can be completed according to the operating mode.

[0033] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A biomimetic butterfly flapping flyer with variable center of gravity steering and variable wing area, characterized in that, The application relates to a variable wing area mechanism and a variable gravity center steering device for a flying vehicle. The variable wing area mechanism is installed on a wing connecting part of the main body of the machine body and is used for driving the same-side front wing and the rear wing of the flying vehicle to produce relative periodic or instructed angle changes, so that the effective windward area of the single-side wing is dynamically changed. The variable gravity center steering device is installed on the central region of the main body of the machine body and is used for driving a centrally arranged counterweight assembly to move along the transverse direction of the main body of the machine body, so that the horizontal position of the gravity center of the flying vehicle is actively and controllably changed. The control unit is configured to optimize the flight lift or auxiliary steering by controlling the variable wing area mechanism and to realize the main steering action of the flying vehicle by controlling the variable gravity center steering device. The variable wing area mechanism comprises a first driving unit, a first transmission assembly and a wing connecting plate assembly.

2. The biomimetic butterfly flapping-wing aircraft according to claim 1, characterized in that, The wing connecting plate assembly comprises a first wing connecting plate and a second wing connecting plate which are relatively rotatably connected. The first driving unit is fixed to the first wing connecting plate. The first transmission assembly connects the output end of the first driving unit and the second wing connecting plate and is used for converting the output motion of the first driving unit into the rotation of the second wing connecting plate. The first driving unit is a linear actuator, the first wing connecting plate is a butterfly front wing connecting plate, and the second wing connecting plate is a butterfly rear wing connecting plate.

3. The biomimetic butterfly flapping-wing aircraft according to claim 2, characterized in that, The first transmission assembly comprises a groove arranged on the butterfly rear wing connecting plate and a rocker arranged on the linear actuator, and the end of the rocker of the linear actuator extends into the groove. The variable wing area mechanism further comprises a limiting block arranged on the butterfly front wing connecting plate and used for limiting the rotation limit position of the butterfly rear wing connecting plate.

4. The biomimetic butterfly flapping-wing aircraft according to claim 3, characterized in that, The variable gravity center steering device comprises a second driving unit arranged on the main body of the machine body, a second transmission assembly and the counterweight assembly.

5. The biomimetic butterfly flapping-wing aircraft according to claim 1, wherein, The counterweight assembly comprises a battery mounting frame swingingly arranged at the tail of the main body of the machine body and a battery arranged in the battery mounting frame. The second transmission assembly connects the output end of the second driving unit and is used for driving the counterweight assembly to reciprocate along the transverse direction of the main body of the machine body. The second driving unit is a rotary actuator.

6. The biomimetic butterfly flapping-wing aircraft according to claim 5, characterized in that, The second transmission assembly comprises a take-up reel, traction lines and an elastic guide. The take-up reel is fixed to the output shaft of the rotary actuator. One end of the two traction lines is connected to the end of the elastic guide, and the other end is wound on the take-up reel in opposite directions. The elastic guide is a bendable carbon rod, one end of which is fixed to the main body of the machine body, and the other end is connected to the two traction lines through the battery mounting frame. The two traction lines are connected to the end of the bendable carbon rod through a buckle rod, two ends of the buckle rod are provided with ring structures for respectively fixing the two traction lines, and the middle section is provided with a through hole for fixing the end of the bendable carbon rod.

7. The biomimetic butterfly flapping-wing aircraft according to claim 6, characterized in that, The control unit is configured to control the variable wing area mechanism to maximize the wing effective windward area in the landing stage of the flying vehicle and to minimize the wing effective windward area in the take-off stage.

8. The biomimetic butterfly flapping-wing aircraft according to claim 1, characterized in that, ​ 9. The biomimetic butterfly flapping-wing aircraft according to claim 1, characterized in that, The control unit is configured to, upon receiving a steering instruction, differentially control the variable wing area mechanisms on the left and right sides, and / or control the variable center-of-gravity steering device to drive the counterweight assembly to laterally deviate.

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