Intelligent morphing wingtip winglet based on piezoelectric fiber composites (MFC) driving

Abstract

The application discloses a smart morphing wing tip winglet driven by piezoelectric fiber composite (MFC), which comprises a wing, a mounting groove is formed in the wing tip of the wing, a piezoelectric material MFC driving element with a size smaller than that of the mounting groove is arranged in the mounting groove, the piezoelectric material MFC driving element is connected with the winglet through a hinge, and the piezoelectric material MFC driving element is connected with a low-voltage power supply; the piezoelectric material MFC sheet is used as a driving element, and the bending deformation of the MFC is converted into the rotary deformation of the wing tip winglet through the hinge; the smart morphing wing tip winglet driven by the piezoelectric fiber composite (MFC) can not only reduce the wing tip vortex and induced drag, but also actively and adaptively adjust the geometric parameters and layout mode of the wing tip winglet according to the flight state and task during the flight of the aircraft, and the shape of the wing is flexibly changed, so that the aircraft can approach the optimal aerodynamic performance through the low input voltage control in each stage of flight.

Description

Technical Field

[0001] This invention belongs to the field of intelligent aircraft structure and piezoelectric material technology, and specifically relates to an intelligent deformable winglet driven by piezoelectric fiber composite material MFC. Background Technology

[0002] During flight, the high-pressure airflow under the wing surface bypasses the wingtip and flows to the upper wing surface, forming a strong vortex that extends a long distance behind the wing. This airflow carries away energy and increases induced drag. Therefore, when an aircraft lands, it leaves a high-intensity contrail that takes 2-3 minutes to dissipate. If the vortex has not completely dissipated, following aircraft will experience violent rolls or a sharp descent, potentially leading to a crash.

[0003] To suppress wingtip vortex generation, NASA engineer R.T. Whitcomb described the basic design and operational effectiveness of winglets in his paper, 'A Design Approach and Selected Wind-Tunnel Results at High Subsonic Speeds For Wing-Tip Mounted Winglets'. Winglets are small wing structures angled to the wing surface, designed to improve flight efficiency by reducing induced drag caused by wingtip vortices. The principle behind their ability to suppress wingtip vortices lies in the fact that the winglet itself can be considered a small wing, capable of generating wingtip vortices. These vortices are generated in the opposite direction to those generated by the main wing and are very close to each other. Through viscous dissipation, the two vortices intertwine and cancel each other out, thus reducing induced drag. Furthermore, the installation of winglets can obstruct airflow around the lower surface of the wing, effectively weakening the intensity of wingtip vortices.

[0004] The geometry and layout of winglets both affect their performance. Optimizing winglet design parameters can effectively improve wing efficiency during the cruise phase; however, during takeoff and climb, winglets designed for the cruise phase can only provide a small aerodynamic gain, and sometimes even have a negative gain effect. Therefore, to achieve optimized aerodynamic performance across the entire flight path, it is necessary to propose a winglet solution that can adaptively deform according to flight mission and conditions. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention aims to provide an intelligent deformable winglet driven by piezoelectric fiber composite material MFC. The intelligent deformable winglet driven by MFC can reduce wingtip vortices and induced drag, and can also actively and adaptively adjust its own geometric parameters and layout according to the flight status and mission during the flight, smoothly changing the shape of the aircraft. Thus, the aircraft can be closer to the optimal aerodynamic performance at all stages of flight. At the same time, it greatly reduces the weight and volume of the drive device, providing a foundation and conditions for the miniaturization and intelligence of intelligent aircraft, and verifying the feasibility of achieving adaptive deformation of intelligent aircraft driven by piezoelectric materials through low input voltage control.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A smart deformable winglet driven by piezoelectric fiber composite material MFC is proposed. The piezoelectric material MFC sheet is used as the driving element to convert the bending deformation of the piezoelectric material MFC into the rotational deformation of the winglet.

[0008] A smart deformable winglet based on piezoelectric fiber composite material MFC drive includes a wing 1, a mounting groove 5 on the wingtip of the wing 2, a piezoelectric material MFC drive element 2 with a size smaller than the mounting groove 5 is disposed in the mounting groove 5, the piezoelectric material MFC drive element 2 is connected to the winglet 3 through a hinge 4, and the piezoelectric material MFC drive element 2 is supplied with a low voltage of 0-5V.

[0009] The piezoelectric material MFC driving element 2 uses a P1 type MFC.

[0010] The angle between the winglet 3 and the vertical plane is defined as the cant angle α, and the change of the cant angle Δα is obtained by formula (1):

[0011]

[0012] Where S is the short handle length of the hinge 4 connected to the winglet 3; y is the bending height of the vertical displacement y of the piezoelectric material MFC drive element 2.

[0013] The beneficial effects of this invention are:

[0014] (1) The structure utilizes the design of the hinge structure to change the bending deformation of the MFC drive structure into the rotational deformation of the winglet, which can effectively amplify the rotation angle of the wingtip winglet.

[0015] (2) The structure is driven by piezoelectric fiber composite material MFC and controlled by DC voltage. It can achieve real-time operation and precise control through low voltage of 0-5V. The structure is simple and does not require other drive control devices.

[0016] (3) The MFC drive structure is located inside the wing, and its deformation is not restricted by the external boundary, which reduces unnecessary constraints and further increases the deformation.

[0017] This invention utilizes piezoelectric material MFC as a driving element to reduce the size of the driving device and achieve real-time adaptive driving and precise control. A hinge 4 is proposed to transform the bending deformation of the piezoelectric material MFC driving element 2 into the rotational deformation of the winglet 3. The principle of amplified deformation of this structure is explained, and the feasibility of achieving adaptive deformation by controlling the piezoelectric material to drive the intelligent aircraft through low input voltage is verified. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the intelligent winglet based on MFC driver according to the present invention.

[0019] Figure 2 This is a schematic diagram of the structure of the wingtip winglet of the present invention being electrically powered.

[0020] Figure 3 This is a schematic diagram of the deformed structure of the wingtip of the present invention after it is not powered.

[0021] Figure 4 This is a diagram showing the driven deformation process of the intelligent deformable winglet of the present invention under different voltages.

[0022] Figure 5 This is a schematic diagram of the modified MFC driver structure. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0024] See Figure 1 A smart deformable winglet based on piezoelectric fiber composite material MFC drive includes a wing 1. A mounting slot 5 is formed at the wingtip of the wing 2. A piezoelectric material MFC drive element 2, smaller than the mounting slot 5, is disposed within the mounting slot 5. The piezoelectric material MFC drive element 2 is connected to the winglet 3 via a hinge 4. The piezoelectric material MFC drive element 2 is supplied with a low voltage of 0-5V. The power supply and DC-DC high-voltage converter are hidden within the wing. The angle between the winglet 3 and the vertical plane is defined as the canard angle α. The MFC drive structure, as a key component of the smart winglet, is used to control the adaptive rotational deformation of the wingtip. As part of the winglet 3, it utilizes… Figure 2 The hinge shown can transmit deformation, converting the bending deformation of the MFC driven structure into the rotational deformation of the wingtip.

[0025] By utilizing the piezoelectric material MFC drive element 2 as the actuation device, the weight and volume of the drive device are greatly reduced, providing a foundation and conditions for the miniaturization and intelligence of intelligent aircraft. The MFC used is of type P1, mainly used for actuation. It utilizes the inverse piezoelectric effect of the piezoelectric material. When an electrical signal is applied, the piezoelectric fibers elongate or shorten along the direction of the electric field, causing the overall structure to expand and contract, thus playing a role in deformation actuation.

[0026] By designing hinge 4, the bending deformation of the MFC drive structure is cleverly converted into the rotational deformation of the wingtip. When the drive voltage is input, the MFC undergoes elongation deformation, causing the base plate to bend, which in turn triggers the rotational deformation of the wingtip 2, thereby changing the outward cant angle α of the wingtip 2.

[0027] By controlling the deformation of piezoelectric materials with a low voltage of 0-5V, the wingtip cannon can be smoothly changed, allowing the intelligent aircraft to adaptively adjust the low driving voltage to change its shape according to the aircraft's angle of attack and different flight missions, thus maintaining optimal aerodynamic performance throughout the entire flight phase.

[0028] Macro-fiber composites (MFCs) are high-performance, durable, and reliable actuating and sensing elements. As a surface-integrable sheet, MFCs can be applied to various types of structures or embedded in composite structures. Internally, an MFC is a laminated structure consisting of rectangular piezoelectric ceramic rods sandwiched between adhesive, electrodes, and a polyimide film layer. The electrodes are connected to the film in an interlaced manner, directly transmitting the applied voltage to or from the strip rods. This packaged layup structure ensures that the MFC can achieve planar polarization, actuation, and sensing. The MFC used in this invention is of type P1, primarily used for actuation, utilizing the inverse piezoelectric effect of the piezoelectric material. When an electrical signal is applied, the piezoelectric fibers elongate or shorten along the direction of the electric field, causing the overall structure to expand and contract, thus providing deformation actuation. The advantages of using MFC for drive are as follows: (1) MFC is flexible, lightweight and durable, easy to install into winglets for drive, with a simple overall structure and no added weight; (2) MFC drives winglets for adaptive deformation control, with precise control and adjustability, enabling real-time control; (3) MFC is driven by the inherent voltage device of the fuselage, without the need for an additional drive device; (4) MFC can provide a maximum driving force of 450N, which can drive the structure to produce greater deformation; (5) Intelligent deformable winglets can more efficiently reduce wingtip vortices and induced drag, as well as additional lift during flight.

[0029] Working principle of the invention:

[0030] The smart winglet structures that deform under no power and those that deform under power are as follows: Figure 2 and Figure 3 As shown. When there is no voltage input, the structure of the piezoelectric material MFC drive element 2 is flat, as... Figure 3 When a driving voltage is applied, the electromechanical coupling characteristics drive the MFC to deform, causing the substrate to bend. The hinge 4 structure enables the winglet to achieve significant rotational deformation, such as... Figure 2 As shown. The outward cant angle α can vary depending on the degree of actuation of the MFC drive structure in the winglet. Figure 2 and Figure 3 The figure shows the bending height of the short shank length s and the vertical displacement y of the MFC drive structure. The change Δα of the wingtip outward cant angle can be obtained by Equation 1:

[0031]

[0032] See Figure 4 Gradually increase the driving voltage, from Figure 4 As can be seen, the wingtip angle gradually decreases, indicating that it is feasible to drive the intelligent aircraft structure to compliantly and adaptively change its shape by using smart materials controlled by low input voltage.

[0033] Additional notes:

[0034] Composite drive board deformation principle

[0035] Because the MFC is a flexible and easily bendable soft actuation sheet, it cannot be directly installed into the overall structure for actuation. Therefore, the MFC needs to be bonded to a rigid substrate plate to form a composite actuation structure to drive the deformation of the winglets. The MFC and substrate plate are bonded together with tight interlayer adhesion. When a DC voltage is applied to drive the P1 type MFC, due to the inverse piezoelectric effect of the piezoelectric material, the MFC linearly elongates or shortens under the voltage. Specifically, under the action of voltage U, the MFC generates strain: ε = βU, where β is the piezoelectric coefficient of the MFC, and the strain direction is the direction of the internal electric field of the MFC. Since the substrate plate is not driven by the voltage (i.e., the substrate plate does not directly deform under voltage), the MFC and substrate plate are bonded together, and the MFC will generate force and torque on the substrate plate. Ultimately, the MFC and substrate plate deform in coordination, bending together under the action of voltage. The deformation principle of the MFC actuation structure is as follows. Figure 5 As shown.

[0036] In summary, the present invention provides an intelligent deformable winglet based on piezoelectric fiber composite material MFC, which can reduce wingtip vortices and induced drag, and can also adaptively adjust its own geometric parameters and layout according to the flight status during the flight, smoothly changing the shape of the wing, so that the aircraft can approach the optimal aerodynamic performance at all stages of flight.

Claims

1. A smart deformable winglet driven by piezoelectric fiber composite material MFC, characterized in that, A mounting slot (5) is provided at the wingtip of the wing (1). A piezoelectric fiber composite material MFC drive element (2) with a size smaller than the mounting slot (5) is provided in the mounting slot (5). The piezoelectric fiber composite material MFC drive element (2) is connected to the winglet (3) through a hinge (4). The piezoelectric fiber composite material drive element (2) is supplied with a low voltage of 0-5V. The piezoelectric fiber composite material MFC drive element (2) uses a P1 type MFC; The angle between the winglet (3) and the vertical plane is defined as the outward cant angle. α Changes in outward tilt angle Obtained through the following formula: Where S is the short handle length of the hinge (4) connected to the winglet (3); y The vertical displacement of the piezoelectric fiber composite MFC drive element (2) y The bending height; By designing the hinge (4), the bending deformation of the piezoelectric fiber composite MFC driving element is converted into the rotational deformation of the winglet (3). When the driving voltage is input, the piezoelectric fiber composite MFC driving element elongates, causing the base plate to bend, which in turn causes the winglet (3) to rotate, thereby changing the outward tilt angle of the winglet (3). α Purpose; The low voltage of 0-5V controls the deformation of the piezoelectric fiber composite material to control the wingtip winglet to smoothly change the cant angle, so that the intelligent aircraft can adaptively adjust the low driving voltage to change its shape according to the aircraft's angle of attack and different flight missions, so as to maintain optimal aerodynamic performance throughout the entire flight phase.

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