CN117682051A - Fishbone-like flexible trailing edge bending wing - Google Patents

Abstract

The invention provides a fishbone-imitated flexible trailing edge camber wing, which comprises a wing body, a middle wing box and a flexible trailing edge section which are connected in sequence; the tail ends of the multiple groups of rigid fishbone joints are hinged in series and then are hinged with the rear edge rigid wing tips to form a fishbone-like structure; the ends of adjacent rigid fishbone condyles are connected through a composite flexible corrugated plate, and the outermost layer of the fishbone-like flexible trailing edge camber wing is bonded with a micro-groove wing skin; the driving device comprises a double-shaft driving motor and a carbon steel aluminum-clad rope, wherein the double-shaft driving motor is fixed on one side of the middle wing box, which is close to the wing body, the carbon steel aluminum-clad rope is arranged in the rigid fishbone joints and the rear edge rigid wing tips in a penetrating mode, and two ends of the carbon steel aluminum-clad rope are respectively wound on two driving shafts of the double-shaft driving motor. The fishbone-like flexible trailing edge bending wing can reduce landing and approach noise caused by gaps, and can simplify the mechanical structure, thereby effectively improving the overall performance of an airplane.

Description

Fishbone-like flexible trailing edge bending wing

Technical Field

The invention relates to a deformable wing technology, in particular to a fishbone-like flexible trailing edge camber wing.

Background

Bionics is a method for solving engineering problems by utilizing the design principle of biological systems in nature. The efficient swimming of fish in water has been one of the ergonomically designed inspiration. The fish bones have the characteristics of light weight and strong strength, can provide enough support, are slender and strong in flexibility, and have extremely high similarity with streamline wings, so that the resistance is reduced and the movement performance of the fish bones is improved. The fishbone-like wing design simulates such a structure by using lightweight, yet strong materials, such as composite materials or advanced alloys, to construct the frame of the wing. The design ensures enough rigidity, reduces the overall weight and improves the flight efficiency.

Conventional high lift devices for wing trailing edges, such as flaps and slats, while providing certain performance advantages in flight, suffer from a number of drawbacks:

1. noise generation: the deployment and retraction of the flaps and slats may generate noise, which is detrimental to both the environmental impact of the aircraft and the comfort of the pilot. With the increasing strictness of aircraft noise limits, this is becoming a problem to be solved.

2. Mechanical complexity: conventional high lift devices typically require complex mechanical systems to implement, including numerous actuators and drive trains. This increases the maintenance costs and the likelihood of failure of the aircraft.

Disclosure of Invention

The invention aims to solve the problems of loud noise and complex mechanical structure of the traditional wing, and provides the fishbone-like flexible trailing edge camber wing which can reduce landing and approach noise caused by gaps and simplify the mechanical structure so as to effectively improve the overall performance of an airplane.

In order to achieve the above purpose, the invention adopts the following technical scheme: the fishbone-like flexible trailing edge camber wing comprises a wing body, a middle wing box, a flexible trailing edge section and a double-shaft driving motor, wherein the wing body, the middle wing box and the flexible trailing edge section are sequentially connected;

the flexible trailing edge section comprises a micro-groove wing skin, a plurality of groups of rigid fishbone sections, a trailing edge rigid wing tip and a composite flexible corrugated plate, wherein the tail ends of the plurality of groups of rigid fishbone sections are hinged in series and then are hinged with the trailing edge rigid wing tip to form an imitation fishbone structure; the sizes of the rigid fishbone condyles from the middle wing box to the rear edge rigid wing tip become smaller in sequence, so that the whole wing forms a smooth wing surface; the ends of adjacent rigid fishbone condyles are connected through a composite flexible corrugated plate, and the outermost layer of the fishbone-like flexible trailing edge camber wing is bonded with a micro-groove wing skin;

the driving device comprises a double-shaft driving motor and a carbon steel aluminum-clad rope, wherein the double-shaft driving motor is fixed on one side, close to the wing body, of the middle wing box, the carbon steel aluminum-clad rope is arranged on the rigid fishbone condyle and the rear edge rigid wing tip in a penetrating mode, and two ends of the carbon steel aluminum-clad rope are respectively wound on two driving shafts of the double-shaft driving motor.

Further, the wing body is in a wing shape, and one end of the wing body is integrally adhered and fixed with the middle wing box to form a wing inner cavity.

Further, a plurality of reinforcing ribs are arranged in the inner cavity of the wing body.

Further, the wing body is made of glass fiber reinforced composite materials, variable rigidity can be achieved by adjusting the thickness of the layering, and the rigidity can be customized according to the requirements of specific applications. For laminated materials, each layer can have an impact on the stiffness of the overall structure. The total stiffness of the structure can be seen as the sum of the stiffness of the layers. As the thickness of a layer increases, the stiffness of that layer increases accordingly. Since the overall stiffness is the sum of the stiffness of the layers, the stiffness of the overall structure will also increase.

Further, the structural shape of the middle wing box can be designed in a diversified manner according to the wing shape and the coordination requirement with the flexible skin so as to meet different adaptability requirements. Preferably, the section of the middle wing box is approximately E-shaped, and has the function of installing and fixing the double-shaft driving motor.

Further, the upper part and the lower part of one side of the middle wing box, which is close to the flexible trailing edge section, are respectively provided with a long strip-shaped through hole for penetrating through the carbon steel aluminum clad rope.

Further, the middle wing box is adhered to the flexible corrugated plate of the trailing edge composite material near two ends of the flexible trailing edge section.

Further, the rigid fish bone condyles are 3-8 groups, preferably 4 groups.

Further, the rigid fishbone condyle takes the plane of the camber line of the wing as a symmetry axis, and comprises an upper bone rib, a middle bone rib and a lower bone rib which are integrally arranged.

Further, the upper and lower rib of the first rigid fish bone condyle (the rigid fish bone condyle near the middle wing box) are inclined backward (the side far from the middle wing box) by 45 ° -75 °, preferably 60 °, respectively, the included angle between the upper and lower rib is 90 ° -150 °, preferably 120 °, and the upper and lower rib of the remaining rigid fish bone condyle are inclined backward by 25 ° -40 °, preferably 30 °, respectively, the included angle between the upper and lower rib is 50 ° -80 °, preferably 60 °.

Further, the head and the tail of the adjacent rigid fishbone joints are hinged through cylindrical pins, so that the flexibility of deformation is improved.

Furthermore, the rigid fishbone condyle is made of glass fiber composite materials and is manufactured through a 3D printing technology, so that the structural manufacturing difficulty is reduced, and the structural weight is reduced on the premise of ensuring the strength, the rigidity and the stability.

Further, the rigid fishbone condyle is symmetrically provided with openings at the middle positions of the upper bone rib and the lower bone rib for penetrating through the carbon steel aluminum-clad rope.

Further, rolling shafts are symmetrically arranged at the holes of the middle wing box and are provided with rolling bearings with the same size, and the rolling bearings are divided into two parts and are adhered and molded on the rolling shafts of the rolling bearings; the odd rigid fishbone condyle is symmetrically provided with rolling shafts at the openings, and is provided with rolling bearings with the same size, and the rolling bearings are divided into two parts and are adhered and molded on the rolling shafts of the rolling bearings. The odd rigid fish bone condyle is as follows: the first rigid fish bone condyle and the third rigid fish bone condyle … ….

Further, under the requirement of meeting the integral structural strength, a round lightening hole is arranged on the rigid fishbone condyle.

Further, the composite flexible corrugated plate is a resin matrix combining high-performance fiber materials and light weight and high strength, a unique corrugated structure is formed by adopting a composite manufacturing technology, the stretching and bending deformation capacity is increased by the structure, the high specific strength and the high specific rigidity of the composite enable the corrugated plate to bear complex mechanical load in the wing, the damping effect is achieved, and the stability of the structure is ensured. The composite flexible corrugated plate provides constraint for the rigid fishbone condyle, can provide support for the micro-groove wing skin, and can not influence the compliant deformation of the micro-groove wing skin, so that the wing can keep a good aerodynamic shape all the time in the wing deformation process.

Further, the micro-groove wing skin is made of carbon fiber composite materials, and the micro-groove is cut off in a numerical control laser cutting machining mode. The presence of micro-grooves can improve air flow, reduce turbulence generation, and thus reduce frictional drag, which is beneficial for both aircraft speed and fuel consumption.

Further, a single wheel is arranged in the trailing edge rigid wing tip, the single wheel is larger than the rolling bearing in size so as to meet the tensile strength requirement, and the bonding mode is the same as that of the rolling bearing. The single wheel rotating shaft is parallel to the rolling bearing rolling shaft.

Further, one end of the carbon steel aluminum-clad rope is wound on one driving shaft of the double-shaft driving motor, the other end of the carbon steel aluminum-clad rope sequentially penetrates through the holes of the upper rib of the rigid fishbone joint, is wound on the single wheel, sequentially penetrates through the holes of the lower rib of the rigid fishbone joint, and then is wound on the other driving shaft of the double-shaft driving motor.

Further, a plurality of bolt holes are formed in one side, close to the wing body, of the middle wing box; the double-shaft driving motor is fixed on the middle wing box through bolts and bolt holes, and the model of the bolts is M10. The double-shaft driving motor is arranged in the middle wing box, the carbon steel aluminum-clad ropes are wound on the two groups of driving shafts, positive and negative currents are input to the motor, and the driving shafts can be controlled to rotate clockwise (anticlockwise) so as to retract the carbon steel aluminum-clad ropes. The rolling bearing is fixed on the rolling shaft of the rigid bone joint, and the rolling bearing has the function that the carbon steel aluminum-clad rope is always clung to the groove of the rolling bearing in the rib deflection process and slides along the driving direction of the double-shaft driving motor. When the double-shaft driving motor works, the rotation moment output by the double-shaft driving motor is transmitted to the rear edge rigid wing tip through the carbon steel aluminum-clad rope. The driving system realizes symmetrical and accurate deflection of the wing along the mean camber line by adjusting the length of the carbon steel aluminum coated rope.

Further, the double-shaft driving motor is a YB2-132S-4H type motor.

Further, the carbon steel aluminum-clad rope is made of a high-strength and wear-resistant material, so that the rope has good load bearing capacity and wear resistance. Aluminum is a relatively lightweight material and coating the carbon steel core with aluminum reduces the weight of the overall rope. This is particularly important for lightweight wing structural design in air traffic transportation.

The fishbone-like flexible trailing edge camber wing has the advantages of simple, reasonable and compact structure, and compared with the prior art, the fishbone-like flexible trailing edge camber wing has the following advantages:

1) The fishbone-like flexible trailing edge bending wing trailing edge structure can simultaneously meet the requirements of accurate deformation and high pneumatic bearing;

2) The invention can realize seamless, smooth and continuous shape change of the continuous trailing edge aerodynamic shape, can realize real-time optimization of the wing profile, reduces landing and approach noise generated by gaps, and can effectively improve the comprehensive performance of the aircraft;

3) The invention adopts the double-shaft driving motor for driving, thereby being beneficial to realizing the driving of the multi-ribbed three-dimensional wing;

4) The carbon steel aluminum-clad rope reduces the complexity of a camber-changing wing trailing edge mechanism and reduces the weight;

5) The invention has the advantages of less number of connecting parts of the whole structure, convenient assembly, disassembly and maintenance of the module, small relative error and high reliability.

In summary, the trailing edge structural design of the present invention aims to achieve camber change of the wing to meet both accurate deformation requirements and high aerodynamic load bearing performance. The design is beneficial to reducing landing and approach noise caused by gaps, and can simplify the mechanical structure, thereby effectively improving the overall performance of the aircraft.

Drawings

FIG. 1 is a schematic structural view of a fish bone-like flexible trailing edge camber wing of the present invention;

FIG. 2 is a schematic structural view of the intermediate wing box and flexible trailing edge section of the present invention;

FIG. 3 is a schematic structural view of a rigid fish bone condyle of the present invention;

FIG. 4 is a schematic view of the articulation of the rigid fish bone condyle of the present invention;

FIG. 5 is a schematic diagram of the structure of the fishbone-imitated flexible corrugated plate;

FIG. 6 is a schematic view of the apparatus of the variable camber trailing-edge driving device of the present invention;

FIG. 7 is an exploded schematic view of the variable camber trailing-edge drive of the present invention;

FIG. 8 is a schematic view of the trailing edge rigid wing tip structure of the present invention.

Reference numerals: 1-a wing body; 2-middle wing box; 3-a flexible trailing edge section; 4-micro-slot wing skin; 5-a first rigid fish bone condyle; 6-a second rigid fish bone condyle; 7-third rigid fish bone condyles; 8-fourth rigid fish bone condyle; 9-a composite flexible corrugated plate; 10-trailing edge rigid wingtips; 11-pins; 12-rolling bearings; 13-rolling bearing rolling shafts; 14-single wheel; 15-a single wheel rolling shaft; 16-carbon steel aluminum coated rope; 17-a double-shaft driving motor; 18-bolts; 19-bolt holes; 20-lightening holes.

Detailed Description

The invention is further illustrated by the following examples:

example 1

The application discloses flexible camber wing trailing edge structure of imitative fish bone, as shown in fig. 1, including wing body 1, middle wing box 2, flexible trailing edge section 3 and biax driving motor 17 specifically include following structure: a micro-groove wing skin 4, a first rigid fishbone condyle 5; a second rigid fish bone condyle 6; a third rigid fish bone condyle 7; fourth rigid fishbone joint 8, composite flexible corrugated plate 9, carbon steel aluminum-clad rope 16, double-shaft driving motor 17 and other parts. The flexible trailing edge section 3 comprises a hinging mechanism formed by a mode of hinging 4 groups of rigid fishbone joints and flexible corrugated plates in sequence, and the hinging mechanism and the rear edge rigid wing tips 7 form an approximate fishbone structure integrally; the sections from the intermediate box 2 to the trailing edge rigid wing tip 10 follow a pattern of successively smaller dimensions so that the entire wing forms a smooth airfoil.

Turbulence is a chaotic flow of air on the surface of the wing that causes an increase in drag. As shown in fig. 2, the surface of the wing wrapping layer contains a micro-groove wing skin 4, which is connected with the internal structure of the skin in a tight adhesion manner, the micro-groove wing skin is made of a carbon fiber composite material, and the micro-groove is cut off in a numerical control laser cutting processing manner. The presence of micro-grooves can improve air flow, reduce turbulence generation, and thus reduce frictional drag, which is beneficial for both aircraft speed and fuel consumption.

The wing body 1 is in a wing shape, and two end parts of the wing body are integrally adhered and fixed with the middle wing box 2 to form a wing inner cavity. A plurality of reinforcing ribs are arranged in the inner cavity of the wing body 1. In the embodiment of the application, the wing body 1 is made of glass fiber reinforced composite material, the variable rigidity can be realized by adjusting the thickness of the layering, and the rigidity can be customized according to the requirements of specific application.

The right end of the wing body 1 is provided with a middle wing box 2, and the structural shape of the middle wing box can be designed in a diversified manner according to the shape of the wing and the coordination requirement of the flexible skin so as to meet different adaptability requirements. In this embodiment, the section of the wing middle box is preferably approximately E-shaped, and the function of installing and fixing the double-shaft driving motor is achieved. The right side of the wing box is provided with a strip-shaped opening for penetrating through the carbon steel aluminum-clad rope and being bonded with the trailing edge composite flexible corrugated plate.

The flexible trailing edge section 3 mainly comprises a first rigid fish bone condyle 5; a second rigid fish bone condyle 6; a third rigid fish bone condyle 7; the fourth rigid fishbone joint 8 and the composite flexible corrugated plate 9 form a multi-section hinged structure, each multi-section structure comprises a plurality of rigid fishbone joints which are hinged in turn to form a fishbone-like structure, and the fishbone-like structure and the composite flexible corrugated plate 9 are bonded and formed; each rigid condyle of the multi-section structure is sequentially reduced in size and comprises an upper rib, a middle rib and a lower rib which are integrally arranged.

Specifically, as shown in fig. 3, the plane of the camber line of the wing is taken as a symmetry axis, the upper rib and the lower rib of the first section are respectively inclined backwards by 60 degrees, and the included angle between the upper rib and the lower rib is 120 degrees. The upper rib and the lower rib of the rest rigid bone segments are respectively inclined backwards by 30 degrees, and the included angle between the upper rib and the lower rib is 60 degrees. As shown in FIG. 4, adjacent rigid condyles are hinged by cylindrical pins 11, increasing the flexibility of the deformation. The rigid condyle 5-8 is made of glass fiber composite materials and is manufactured through a 3D printing technology, so that the structural manufacturing difficulty is reduced, and the structural weight is reduced on the premise of ensuring the strength, the rigidity and the stability. The rigid fishbone condyle 5-8 is provided with an opening at the middle position of the upper and lower condyles for penetrating through the carbon steel aluminum-clad rope 13. At the open hole of the middle wing box, the open holes of the first rigid fishbone joint 5 and the third rigid fishbone joint 7 are symmetrically provided with rolling shafts respectively and are provided with rolling bearings with the same size, and the rolling bearings 12 are divided into two parts and are adhered and molded and fixed on the rolling bearing rolling shafts 13. In addition, a circular lightening hole 20 is provided on each rigid fish bone condyle, as required to meet overall structural strength.

Specifically, as shown in fig. 5, the composite flexible corrugated plate 9 combines a high-performance fiber material and a light high-strength resin matrix, adopts a composite manufacturing technology to form a unique corrugated structure, the structure increases stretching and bending deformation capacity, and the high specific strength and the high specific rigidity of the composite material enable the corrugated plate to bear complex mechanical loads in the wing, so that a damping effect is achieved, and the stability of the structure is ensured. The composite flexible corrugated plate 9 provides constraint, can provide support for the micro-groove wing skin 4, and does not influence the compliant deformation of the micro-groove wing skin 4, so that the wing can always maintain a good aerodynamic shape in the wing deformation process.

As shown in fig. 6 and 7, in order to allow the camber wing structure of the present invention to be continuously deformed, a driving system is provided in the intermediate wing box 2. As shown in fig. 6 and 7, the drive system includes a carbon steel aluminized rope 16 and a biaxial drive motor 17. The method comprises the following steps: the front part of the middle wing box 2 is provided with a plurality of bolt holes 19; specifically, 8 bolts 18 are used to fix the biaxial drive motor 17, and the bolt model number is M10. The double-shaft driving motor 17 is arranged on the middle wing box 2, the carbon steel aluminum coated rope 16 is wound on the two groups of driving shafts, positive and negative currents are input to the motor, and the driving shafts can be controlled to rotate clockwise (counter) so as to retract the carbon steel aluminum coated rope 16. The rolling bearing 12 is fixed on the rolling shaft 13 of the rigid bone joint, and the rolling bearing 12 has the function that the carbon steel aluminum coated rope 16 is always clung to the groove of the rolling bearing in the rib deflection process and slides along the driving direction of the double-shaft driving motor. In operation, the rotational torque output by the dual-shaft drive motor 17 is transmitted to the trailing edge rigid wing tip 10 shown in fig. 8 through the carbon steel aluminum-clad rope 16, wherein a single wheel 14 is arranged in the trailing edge rigid wing tip 10, and the single wheel is larger than the rolling bearing in size so as to meet the tensile strength requirement, and the bonding mode is the same as the rolling bearing. The driving system realizes symmetrical and accurate deflection of the wing along the mean camber line by adjusting the length of the rope. In the embodiment, the motor is a YB2-132S-4H type motor. In particular, carbon steel coated aluminum rope 16 is a high strength, wear resistant material, which provides such rope with good load carrying capacity and wear resistance. Aluminum is a relatively lightweight material and coating the carbon steel core with aluminum reduces the weight of the overall rope. This is particularly important for lightweight wing structural design in air traffic transportation.

The fishbone-like flexible trailing edge camber wing provided by the embodiment of the invention is divided into a wing body 1, a middle wing box 2 and a flexible trailing edge section 3 along the chord direction, and the multi-section structure of the flexible trailing edge section 3 mainly comprises a plurality of rigid bone joints in a hinged mode to form a structure similar to the fishbone bone joints. In operation, the rotational torque output by the dual shaft drive motor 17 is transferred to the trailing edge rigid wing tip 10 via the carbon steel aluminized rope 16, depending on the flight conditions. By adjusting the length of the rope, the symmetrical and accurate deflection of the wing along the camber line is realized, and the requirements of seamless, smooth and continuous shape change of the pneumatic shape of the continuous trailing edge are met. The invention optimizes the aerodynamic performance of the aircraft by actively adjusting the camber of the trailing edge of the wing, thereby achieving the aims of lifting force and reducing resistance. The surface of the wing adopts a design containing micro grooves, namely a micro groove wing skin 4, so as to enhance the drag reduction effect of the wing. In addition, the front edge rigid section adopts a hollow structure of the reinforcing ribs, so that the pneumatic force can be borne, the dead weight of the wing is effectively reduced, and the effects of energy conservation and emission reduction are realized.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims (10)

1. The fishbone-like flexible trailing edge camber wing is characterized by comprising a wing body (1), a middle wing box (2), a flexible trailing edge section (3) and a double-shaft driving motor (17), wherein the wing body (1), the middle wing box (2) and the flexible trailing edge section (3) are sequentially connected;

the flexible trailing edge section (3) comprises a micro-groove wing skin (4), a plurality of groups of rigid fishbone sections, a trailing edge rigid wing tip (10) and a composite flexible corrugated plate (9), wherein the tail ends of the groups of rigid fishbone sections are hinged in series and then are hinged with the trailing edge rigid wing tip (7) to form a fishbone-like structure; the sizes of the rigid fishbone condyles from the middle wing box (2) to the rear edge rigid wing tip (10) become smaller in sequence; the ends of adjacent rigid fishbone condyles are connected through a composite flexible corrugated plate (9), and the outermost layer of the fishbone-like flexible trailing edge camber wing is bonded with a micro-groove wing skin (4);

the driving device comprises a double-shaft driving motor (17) and a carbon steel aluminum-clad rope (16), wherein the double-shaft driving motor (17) is fixed on one side, close to the wing body (1), of the middle wing box (2), the carbon steel aluminum-clad rope (16) is arranged in the rigid fishbone condyle and the rear edge rigid wing tip (10) in a penetrating mode, and two ends of the carbon steel aluminum-clad rope (16) are respectively wound on two driving shafts of the double-shaft driving motor (17).

2. The fishbone simulated flexible trailing edge camber wing according to claim 1, wherein a plurality of stiffeners are provided in the wing inner cavity of the wing body (1).

3. The fishbone flexible trailing edge camber airfoil of claim 1 wherein the intermediate wing box (2) is approximately E-shaped in cross section.

4. The fishbone simulated flexible trailing edge camber wing according to claim 1, wherein the upper and lower parts of the side of the intermediate wing box (2) adjacent to the flexible trailing edge section (3) are provided with elongated through holes respectively.

5. The fish bone-like flexible trailing edge camber airfoil of claim 1 wherein the upper and lower rib sections of the first section of rigid fish bone condyle are each inclined rearwardly 45 ° -75 ° with an included angle between the upper and lower rib sections of 90-150 °; the upper rib and the lower rib of the rest rigid fish bone condyle are respectively inclined backwards by 25-40 degrees, and the included angle between the upper rib and the lower rib is 50-80 degrees.

6. The fishbone-like flexible trailing edge camber airfoil of claim 1 wherein adjacent rigid fishbone segments are hinged at their head and tail by cylindrical pins (11).

7. The simulated fish bone flexible trailing edge camber wing of claim 1 wherein said rigid fish bone condyle is symmetrically provided with openings in the upper and lower bone ribs.

8. The fishbone-imitated flexible trailing edge camber wing according to claim 1, wherein the middle wing box (2) is symmetrically provided with rolling shafts at the openings and is provided with rolling bearings with the same size, and the rolling bearings (12) are divided into two parts and are adhered and fixed on the rolling bearing rolling shafts (13); the odd rigid fishbone condyle is symmetrically provided with rolling shafts at the holes, and rolling bearings with the same size are installed, and the rolling bearings (12) are divided into two parts and are adhered and fixed on the rolling bearing rolling shafts (13).

9. The fishbone flexible trailing edge camber airfoil of claim 1 wherein a single wheel (14) is disposed within the trailing edge rigid wing tip (10), the single wheel (14) axis of rotation being parallel to the rolling bearing axis of rotation (13).

10. The fishbone-like flexible trailing edge camber wing according to claim 1, wherein the carbon steel aluminum clad rope (16) is wound on one driving shaft of the double-shaft driving motor (17) at one end, and is wound on the single wheel (14) after sequentially passing through the holes of the upper rib of the rigid fishbone segment and then sequentially passing through the holes of the lower rib of the rigid fishbone segment, and is wound on the other driving shaft of the double-shaft driving motor (17).