CN115892444A

CN115892444A - Intelligent deformation wingtip winglet driven based on piezoelectric fiber composite material MFC

Info

Publication number: CN115892444A
Application number: CN202211575471.6A
Authority: CN
Inventors: 肖江海; 李群; 陈祥华; 张堰铭
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 2022-12-08
Filing date: 2022-12-08
Publication date: 2023-04-04

Abstract

An intelligent deformation wing tip winglet based on piezoelectric fiber composite material MFC driving comprises a wing, wherein a mounting groove is formed in the wing tip of the wing, a piezoelectric material MFC driving element with the 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 low voltage; the bending deformation of the MFC is converted into the rotation deformation of the wingtip winglet through the hinge by using the piezoelectric MFC sheet as a driving element; the intelligent deformable wingtip winglet driven by the piezoelectric fiber composite MFC can reduce wingtip vortex and induced resistance, can actively and adaptively adjust the geometrical parameters and the layout mode of the wingtip winglet according to the flight state and task in the flight process of an aircraft, and flexibly change the shape of the wingtip winglet, so that the aircraft can be controlled to approach to the optimal aerodynamic performance through low input voltage in each flight stage.

Description

Intelligent deformation wingtip winglet based on piezoelectric fiber composite material MFC driving

Technical Field

The invention belongs to the technical field of intelligent aircraft structures and piezoelectric materials, and particularly relates to an intelligent deformable wingtip winglet based on MFC (micro-fuel cell) driving of a piezoelectric fiber composite material.

Background

During flight of the aircraft, the high-pressure airflow at the lower wing surface of the wing slightly bypasses the wing to form strong vortex airflow to the upper wing surface and extends a long distance backwards from the wing. These air flows carry away energy while increasing the induced drag. Therefore, the aircraft drags a high-strength wake vortex at the rear when landing, and takes 2 to 3 minutes to dissipate. When the vortex is not fully dissipated, the following aircraft will roll or descend violently, and even crash.

In order to suppress the generation of Wing tip vortices, NASA technicians, r.t. wheats, describe the basic design and operation efficiency of 'winglets' in 'adesgeachandselectedwind-tunnelresultsathighSubsonics SpeedsForwing-tippoundWingles' design method for wingtips with high subsonic speed and selected wind tunnel results, the winglets are winglet structures which are at a certain angle to the Wing surface, and the flight efficiency is improved by reducing the induced drag caused by the Wing tip vortices. The principle of suppressing the wing tip vortex is that the winglet itself can be regarded as a small wing, the wing tip vortex can be generated, and the direction of the generated wing tip vortex is opposite to the direction of the wing tip vortex generated by the main wing and is very close to the main wing. Under the action of viscous dissipation, the two eddy currents are intertwined and offset with each other, thereby achieving the purpose of reducing induced resistance. And the wingtip winglet can be arranged to block the streaming of the lower surface of the wing, so that the strength of the wing tip vortex can be effectively weakened.

The geometric parameters and the layout of wingtips winglets have an influence on their effectiveness. The design parameters of wingtip winglets are optimized, so that the efficiency of wings can be effectively improved in the cruise stage of the airplane; however, in the takeoff and climbing phases of the airplane, the winglet designed for the cruise phase can only bring small aerodynamic increment, and sometimes even has the effect of negative gain. Therefore, in order to achieve the effect of optimizing aerodynamic performance over the full range, it is necessary to provide a solution for wingtips that is adaptively deformable in accordance with flight mission and conditions.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide the intelligent deformable wing tip winglet based on the driving of the piezoelectric fiber composite material MFC, and the intelligent deformable wing tip winglet based on the driving of the MFC can reduce the tip vortex and the induced resistance of the winglet, can also actively and adaptively adjust the geometric parameters and the layout mode of the winglet according to the flight state and tasks in the flight process of an airplane, and flexibly changes the shape of the airplane, so that the airplane can approach to the optimal pneumatic performance in each flight stage, meanwhile, the weight and the volume of a driving device are greatly reduced, a foundation and conditions are provided for the miniaturization and the intellectualization of an intelligent aircraft, and the feasibility of controlling the piezoelectric material to drive the intelligent aircraft to realize the adaptive deformation through low input voltage is verified.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

an intelligent deformation wingtip winglet based on piezoelectric fiber composite material MFC driving utilizes a piezoelectric material MFC sheet as a driving element to convert bending deformation of the piezoelectric material MFC into rotation deformation of the wingtip.

The intelligent deformation wingtip winglet based on the driving of the piezoelectric fiber composite MFC comprises a wing 1, wherein a mounting groove 5 is formed in the wingtip of the wing 2, a piezoelectric MFC driving element 2 with the size smaller than that of the mounting groove 5 is arranged in the mounting groove 5, the piezoelectric MFC driving element 2 is connected with a winglet 3 through a hinge 4, and the piezoelectric MFC driving element 2 is connected with a low voltage of 0-5V.

The MFC adopted by the piezoelectric material MFC driving element 2 is P ₁ And (4) molding.

The angle between the winglet 3 and the vertical is defined as the camber angle α, and the change in camber angle Δ α is obtained by equation (1):

wherein S is the short handle length of the hinge 4 connected to the winglet 3; y is the bending height of the piezoelectric material MFC driving element 2 for vertical displacement y.

The invention has the beneficial effects that:

(1) The structure utilizes the design of a hinge structure, changes the bending deformation of the MFC driving structure into the rotation deformation of the winglet, and can effectively enlarge the rotation angle of the winglet;

(2) The structure is based on the driving of the piezoelectric fiber composite MFC, is controlled by direct current voltage, can realize real-time control and accurate control through low voltage of 0-5V, and has simple structure without other driving control devices;

(3) The MFC driving structure is positioned in the wing, deformation of the MFC driving structure is not limited by an external boundary, unnecessary constraint is reduced, and deformation is further increased.

The invention uses the piezoelectric material MFC as a driving element, reduces the volume of the driving device and realizes real-time self-adaptive driving and accurate control; a hinge 4 is provided to convert the bending deformation of the driving element 2 of the piezoelectric material MFC into the rotation deformation of the winglet 3; by explaining the principle of amplifying deformation of the structure, the feasibility of realizing self-adaptive deformation by controlling the piezoelectric material to drive the intelligent aircraft through low input voltage is verified.

Drawings

Fig. 1 is a schematic structural diagram of the intelligent wing tip winglet based on MFC driving in the invention.

Fig. 2 is a schematic view of the structure of the invention with the slightly smaller wing electrified.

Fig. 3 is a schematic diagram of a deformed configuration of the tip winglet of the present invention shown without power.

FIG. 4 is a diagram of the driven deformation process of the intelligently deformable winglet under different voltages.

Fig. 5 is a schematic diagram of a variation of the MFC driving structure.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Referring to fig. 1, the intelligent deformable wing tip winglet based on driving of the piezoelectric fiber composite material MFC comprises a wing 1, wherein a mounting groove 5 is formed in the wing tip of the wing 2, a piezoelectric material MFC driving element 2 with the size smaller than that of the mounting groove 5 is arranged in the mounting groove 5, the piezoelectric material MFC driving element 2 is connected with a winglet 3 through a hinge 4, and the piezoelectric material MFC driving element 2 is powered on by low voltage of 0-5V. The power supply and the DC-DC high voltage converter are hidden inside the wing and the angle between the winglet 3 and the vertical is defined as the camber angle alpha. The MFC driving structure is used as a key component of the intelligent winglet and is used for controlling the self-adaptive rotary deformation of the slightly smaller wing of the wing. As part of the winglet 3 a hinge is used as shown in fig. 2, which can transmit deformation, converting the bending deformation of the MFC driven structure into a rotational deformation of the tip winglet.

The driving element 2 of the piezoelectric material MFC is used as a driving element, so that the weight and the volume of the driving device are greatly reduced, and a foundation and conditions are provided for miniaturization and intellectualization of the intelligent aircraft. The MFC adopted is P ₁ The piezoelectric fiber is mainly used for driving, namely, an inverse piezoelectric effect of a piezoelectric material is utilized, an electric signal is input, and the piezoelectric fiber is stretched or shortened along the direction of an electric field under the action of the electric field, so that the whole structure is stretched and contracted, and the deformation driving effect is achieved.

The bending deformation of the MFC driving structure is ingeniously and delicately converted into the rotation deformation of the slight wing by the design of the hinge 4. When the driving voltage is input, the MFC generates elongation deformation to cause the base plate to generate bending deformation, and then the linkage wing tip small wing 2 generates rotation deformation, so that the purpose of changing the camber angle alpha of the wing tip small wing 2 is achieved.

The piezoelectric material deformation is controlled through the low voltage of 0-5V to control the gentle and flexible change camber angle of a slightly smaller wing of the wing, so that the intelligent aircraft can adaptively adjust the low driving voltage according to the attack angle of the aircraft and different flight tasks to change the appearance, and the optimal aerodynamic performance is kept in the full flight stage.

The piezoelectric fiber composite MFC (Macro-fiber composite) is a driving element and a sensing element with high performance, high durability and high reliability. As a thin sheet whose surface can be integrated, MFC can be applied to various types of structures or embedded in a composite structure, and inside of MFC is a laminated laid structure composed of a rectangular piezoelectric ceramic rod sandwiched between an adhesive, an electrode and a polyimide film layer. The electrodes are connected to the membrane in an interdigitated manner to transmit an applied voltage directly to or from the ribbon rod. The packed layering structure ensures that the MFC can generate plane polarization, driving and sensing. The MFC adopted in the invention is P ₁ The piezoelectric element is mainly used for driving, namely, utilizing the inverse piezoelectric effect of a piezoelectric material. When an electric signal is input, the piezoelectric fiber is extended or shortened along the direction of the electric field under the action of the electric field,the whole structure is extended and contracted, and the function of deformation driving is achieved. The advantages of driving with MFC are as follows: (1) The MFC is flexible, light, durable, easy to be installed in a winglet for driving, simple in overall structure and free from additional weight; (2) The MFC drives the wingtip winglet to perform self-adaptive deformation control, is accurate and adjustable in control, and can realize real-time control; (3) The MFC is driven by the inherent voltage device of the body, and an additional driving device is not needed; (4) The MFC can provide a driving force of 450N at most, and the structure can be driven to deform more; (5) The intelligent deformation wingtip winglet can more effectively reduce wing tip vortex and induced resistance and add lift force in the flight process.

The working principle of the invention is as follows:

the smart wing slightly smaller wing structures without electric deformation and with electric deformation are shown in fig. 2 and 3, respectively. The piezoelectric material MFC driving element 2 is flat in structure when no voltage is inputted, as shown in fig. 3. When a driving voltage is applied, the electromechanical coupling characteristics drive the MFC to deform, resulting in a bending deformation of the substrate, and the hinge 4 structure enables the winglet to achieve significant rotational deformation, as shown in fig. 2. The camber angle alpha may vary depending on the degree of actuation of the MFC actuation structure in the winglet. The short handle length s and the bending height of the MFC drive structure vertical displacement y are shown in fig. 2 and 3, and the change in wing camber angle Δ α slightly smaller for the wings can be obtained by equation 1:

referring to fig. 4, the gradually increasing driving voltage, as can be seen from fig. 4, the wing camber angle is gradually decreased slightly, which illustrates that it is feasible to drive the smart aircraft structure to change its shape flexibly and adaptively through the smart material controlled by the low input voltage.

Additional description:

deformation principle of composite driving plate

The MFC is a soft driving sheet which is very flexible and easy to bend, and cannot be directly installed in an integral structure for driving, so the MFC needs to be adhered to a rigid base plate to serve as a composite driving structure for driving the winglet to deform. MFC and baseThe body plates are adhered and tightly adhered. DC voltage is introduced to drive P ₁ In the MFC type, due to the inverse piezoelectric effect of the piezoelectric material, the MFC linearly elongates or shortens and deforms under the voltage. The concrete expression is as follows: under the action of the voltage U, the MFC is strained: epsilon = betaU, where beta is the voltage coefficient of variation of MFC and the direction of strain is the direction of the electric field inside MFC. Because the substrate plate is not driven by voltage (i.e. the substrate plate does not directly deform to voltage), the MFC is bonded with the substrate plate layer, and the MFC generates force and moment to the substrate plate. Finally, the MFC and the substrate plate are cooperatively deformed and jointly bent under the action of voltage. The principle of deformation of the MFC driving structure is shown in fig. 5.

In conclusion, the intelligent deformable wingtip winglet based on the piezoelectric fiber composite MFC can reduce the wingtip vortex and induced resistance, and can adaptively adjust the geometrical parameters and the layout mode of the wingtip winglet according to the flight state in the flight process of an airplane to flexibly change the shape of the wingtip winglet, so that the airplane can approach to the optimal aerodynamic performance in each flight stage.

Claims

1. The intelligent deformation wingtip winglet based on the driving of the piezoelectric fiber composite material MFC is characterized in that a piezoelectric material MFC sheet is used as a driving element, and the bending deformation of the piezoelectric material MFC is converted into the rotation deformation of the wingtip winglet.

2. The utility model provides an intelligence wingtip winglet that warp based on drive of piezoelectric fiber composite material MFC, includes wing (1), its characterized in that, opens at wing (2) wingtip has mounting groove (5), is provided with piezoelectric material MFC drive element (2) that the size is less than mounting groove (5) in mounting groove (5), piezoelectric material MFC drive element (2) with through hinge (4) connection winglet (3), piezoelectric material MFC drive element (2) logical 0-5V low-voltage.

3. An intelligent deformable winglet based on piezoelectric fiber composite MFC drive according to claim 2, wherein the piezoelectric material MFC drive element (2) uses MFC P as P ₁ And (4) molding.

4. An intelligent morphing winglet based on piezoelectric fibre composite MFC actuation according to claim 2, characterized in that the angle between the winglet (3) and the vertical is defined as camber angle α, the change in camber angle Δ α is obtained by equation 1:

wherein S is the short handle length of the hinge 4 connected to the winglet 3; y is the bending height of the piezoelectric material MFC driving element 2 by the vertical displacement y.