Flexible swing wing of underwater bionic propeller and flexible swing wing design method

Abstract

The invention relates to the technical field of swing wing structure design, in particular to a flexible swing wing of an underwater bionic propeller and a flexible swing wing design method.The flexible swing wing is provided with a flexible swing wing body and is characterized in that a driving rod mounting hole is formed in the front end of the flexible swing wing body, and a driving rod is inserted into the driving rod mounting hole; at least two parallel beam holes are formed in the portion, on the rear side of the driving rod mounting hole, of the flexible swing wing body, based on the S-shaped deformation rule of parallel beams, when the flexible swing wing is subjected to the hydrodynamic force effect, more deformation of the flexible swing wing occurs at the position close to the front half portion of the wing section, a certain attack angle is formed, small deformation of the rear half portion of the wing section is kept, and therefore the flexible swing wing is more flexible. Therefore, the flexible swing wing keeps a good hydrodynamic geometrical shape, and the hydrodynamic performance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of swing wing structure design, in particular to a flexible swing wing of an underwater bionic propeller and a flexible swing wing design method. Background Art

[0002] As we all know, swing wings are highly efficient and maneuverable biomimetic propulsion devices. They can be used to increase thrust on ships or drive oscillating flow turbines. Swing wings as propulsion devices can be roughly divided into three types based on their drive mode: fully active rigid wings; semi-active spring-constrained rigid wings; and flexible swing wings.

[0003] The first type, a fully actively driven rigid wing, is optimally designed for a combined heave and pitch motion, with a certain phase difference between the two degrees of freedom. This requires complex mechanisms to achieve linked actuation of the two degrees of freedom, or direct independent actuation and linked control of the two degrees of freedom. Both approaches complicate the drive mechanism for the swing wing, making it difficult to implement and reducing reliability. Some researchers have also simplified the drive mechanism by limiting one degree of freedom, such as a swing wing with pure heave motion or a swing wing with pure pitch motion, but these designs significantly reduce the performance of the swing wing.

[0004] The second type, semi-active spring-constrained rigid wings, also optimally utilize a combined heave and pitch motion. However, heave is typically actively driven, while pitch is controlled by a combination of torsion spring constraints and the hydrodynamic pitching torque. This latter type of control is passive, simplifying the drive mechanism. However, it also presents another challenge: in underwater environments, torsion springs are susceptible to rust and fatigue failure.

[0005] The third type, flexible winglets, utilize flexible materials such as rubber or silicone, allowing them to deform under hydrodynamic forces to adapt to specific operating requirements. Therefore, only heave motion is required for actuation. This simplifies the drive mechanism and provides improved fatigue resistance. However, flexible winglets also present challenges. Their deformation patterns often make it difficult to achieve an optimal geometry through design, resulting in reduced hydrodynamic performance. Summary of the Invention

[0006] The purpose of the present invention is to solve the above-mentioned deficiencies in the prior art and to provide a flexible swing wing and a flexible swing wing design method for an underwater bionic propulsion device with a simple structure that utilizes the deformation characteristics of parallel beams to control the deformation law of the flexible swing wing, thereby improving the hydrodynamic performance of the flexible swing wing.

[0007] The technical solution adopted by the present invention to solve its technical problem is: A flexible wing of an underwater bionic thruster, which has a flexible wing body. It is characterized in that a driving rod mounting hole is provided at the front end of the flexible wing body, a driving rod is inserted into the driving rod mounting hole, and at least two parallel beam holes are provided on the flexible wing body behind the driving rod mounting hole.

[0008] For the flexible wing body of the present invention, flexible material sealing layers are provided on both end faces, and the flexible material sealing layers cover both end faces of the flexible wing body to seal the parallel beam holes.

[0009] The wing surface of the flexible wing body of the present invention is wrapped with a reinforcing fiber layer to prevent tearing when the flexible wing is deformed.

[0010] The driving rod mounting hole of the present invention is a special-shaped hole, and the part of the driving rod inserted into the driving rod mounting hole fits with the special-shaped hole, increasing the connection area between the driving rod and the wing, providing sufficient rigidity for the front part of the wing, improving the adhesion force, and the part of the driving rod extending out of the driving rod mounting hole at one end is cylindrical for easy connection with the driver.

[0011] The driving rod of the present invention is arranged within the range of the leading edge L of the wing, 0.1c < L < 0.2c, where c is the chord length, and the minimum thickness t0 of the flexible material on the outer edge of the driving rod is not less than 1% of the chord length c.

[0012] The length of the parallel beam hole of the present invention is L1, the thickness from the parallel beam hole to the edge of the flexible wing is t1, t1 is not less than 0.5% of the chord length c, the thickness of the support partition between the two parallel beam holes is b1, and the distance between the parallel beam hole and the driving rod is also b1, b1 ≥ 2t1.

[0013] A design method for a flexible wing of an underwater bionic thruster, which is characterized in that the design method steps are as follows: (1) Determine the wing parameters: Design the chord length c of the wing, in m, design the span h, in m, design the forward speed V, in m / s, and design the heaving speed U at the middle position of the heaving motion, in m / s; (2) Calculate the hydrodynamic angle θ according to the wing parameters: The formula for the hydrodynamic angle θ is: θ = arctan(U / V). Substitute the parameters in step (1) into the above formula to obtain the hydrodynamic angle θ, in rad; (3) Determine the angle of attack α of the flexible wing after deformation and obtain the deformation amount d at the tail of the wing: According to the formulas β = θ - α and d = βc, substitute the determined angle of attack α of the flexible wing after deformation and the hydrodynamic angle θ in step (2) into the above formulas to obtain the deformation amount d at the tail of the wing, in m, and the angle of attack α of the flexible wing after deformation, in rad; (4) Calculate the force F on the flexible wing: According to the formula F = 2παρ(U 2 +V 2)hc / 2, substitute the parameters in step (1) and step (3) into the above formula to obtain the force F on the flexible flap, in N; (5) Determine the elastic modulus of the flexible swing wing and the number of parallel beam holes to obtain the ratio of the length of the parallel beam hole L1 to the thickness from the parallel beam hole to the edge of the flexible swing wing t1: Design the elastic modulus E of the flexible swing wing in MPa, and design the number of parallel beams N. According to the relationship Available Substitute the elastic modulus E of the flexible swing wing, the number of designed parallel beams N, the span h in step (1), the deformation d of the swing wing tail in step (3), and the force F on the flexible swing wing in step (5) into the above formula to obtain the ratio of the length of the parallel beam hole L1 to the thickness from the parallel beam hole to the edge of the flexible swing wing t1; (5) Obtain the thickness t1 from the parallel beam hole to the edge of the flexible swing wing, the length L1 of the parallel beam hole, the thickness of the supporting partition between the two parallel beam holes, and the distance b1 between the parallel beam hole and the driving rod: The design requires that the thickness t1 from the parallel beam hole to the edge of the flexible swing wing is not less than 0.5% of the chord length c. According to the value of the chord length c in step (1), the value of t1 is taken. Then, according to the ratio of the length L1 of the parallel beam hole obtained in step (4) to the thickness t1 from the parallel beam hole to the edge of the flexible swing wing, the length of the parallel beam hole is obtained as L. 1. The design requirement is b1 ≥ 2t1. Therefore, the value of b1 is determined based on the thickness t1 from the parallel beam hole to the edge of the flexible swing wing. The final values ​​are the thickness t1 from the parallel beam hole to the edge of the flexible swing wing, the length L1 of the parallel beam hole, the thickness of the supporting diaphragm between the two parallel beam holes, and the distance b1 between the parallel beam hole and the driving rod. The units of the thickness t1 from the parallel beam hole to the edge of the flexible swing wing, the length L1 of the parallel beam hole, the thickness of the supporting diaphragm between the two parallel beam holes, and the distance b1 between the parallel beam hole and the driving rod are all in mm. (6) Wrapping the reinforcing fiber layer and the flexible material sealing layer: bonding the flexible material sealing layer to the two end surfaces of the flexible swing wing body, the flexible material sealing layer covers the two end surfaces of the flexible swing wing body to seal the parallel beam holes, and the wing surface of the flexible swing wing body is wrapped with the reinforcing fiber layer; (7) Inflation inside the parallel beam hole: pressurize and inflate the inside of the parallel beam hole to balance the external water pressure.

[0014] In step (6) of the present invention, the thickness of the flexible material sealing layer is 1.5%-2.5% of the chord length, and the thickness of the reinforcing fiber layer is 1.5%-2.5% of the chord length; In step (7) of the present invention, the internal air pressure of the parallel beam hole is the same as the external water pressure, which is used to balance the external water pressure and prevent the parallel beam hole from being sunken due to the effect of the water pressure.

[0015] Due to the adoption of the above structure and method, the present invention has the advantages of simple structure, utilizing the deformation characteristics of parallel beams to control the deformation law of the flexible swing wing, thereby improving the hydrodynamic performance of the flexible swing wing, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention.

[0017] Figure 2 It is a structural schematic diagram of the driving rod of the present invention.

[0018] Figure 3 This is a structural diagram of the flexible swing wing without parallel beam hole structure of the present invention.

[0019] Figure 4 This is a structural diagram of the flexible swing wing with a parallel beam hole structure of the present invention.

[0020] Figure 5 It is the deformation state diagram of the flexible swing wing, where the dotted line is the original wing shape and the solid line is the wing shape after deformation under force.

[0021] Figure 6 This is a deformation diagram of the flexible swing wing under the action of hydrodynamic force. The long dashed line is the original flexible swing wing, the solid line is the geometric deformation of the flexible swing wing of this patent, and the short dashed line is the ideal rigid airfoil with a certain angle of attack.

[0022] Figure 7 It is a force analysis diagram of the parallel beam of the present invention.

[0023] Reference numerals: flexible swing wing body 1, driving rod 2, parallel beam hole 3, flexible material sealing layer 4, reinforcing fiber layer 5, DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the accompanying drawings: As shown in the accompanying drawings, a flexible swing wing of an underwater bionic propulsion system is provided with a flexible swing wing body 1, which is characterized in that a drive rod mounting hole is provided at the front end of the flexible swing wing body 1, a drive rod 2 is inserted into the drive rod mounting hole, and at least two parallel beam holes 3 are provided on the flexible swing wing body 1 behind the drive rod mounting hole.

[0025] The driving rod 2 is bonded to the driving rod mounting hole by glue or directly embedded in the driving rod mounting hole.

[0026] Furthermore, both end surfaces of the flexible swing wing body 1 are provided with flexible material sealing layers 4 , which cover the both end surfaces of the flexible swing wing body 1 to seal the parallel beam holes 3 .

[0027] Furthermore, the wing surface of the flexible swing wing body 1 is wrapped with a reinforcing fiber layer 5 to prevent the flexible swing wing from being torn when deformed.

[0028] Furthermore, the driving rod mounting hole is a special-shaped hole. The part of the driving rod 2 inserted into the driving rod mounting hole is matched with the special-shaped hole, increasing the connection area between the driving rod 2 and the swing wing, providing sufficient rigidity for the front part of the swing wing, improving the adhesion force. The part of one end of the driving rod 2 extending out of the driving rod mounting hole is cylindrical, facilitating the connection with the driver.

[0029] Furthermore, the driving rod 2 is arranged within the range of the leading edge L of the swing wing, where 0.1c < L < 0.2c, and c is the chord length. The minimum thickness t0 of the flexible material on the outer edge of the driving rod 2 is not less than 1% of the chord length c.

[0030] Furthermore, the length of the parallel beam hole 3 is L1, the thickness from the parallel beam hole 3 to the edge of the flexible swing wing is t1, t1 is not less than 0.5% of the chord length c, the thickness of the support partition between the two parallel beam holes 3 is b1, and the distance between the parallel beam hole 3 and the driving rod 2 is also b1, where b1 ≥ 2t1.

[0031] A design method for the flexible swing wing of an underwater bionic thruster, characterized in that the design method steps are as follows: (1) Determine the swing wing parameters: Design the chord length c of the swing wing, with the unit of m, design the span h, with the unit of m, design the forward speed V, with the unit of m / s, and design the heaving speed U at the middle position of the heaving motion, with the unit of m / s; (2) Calculate the hydrodynamic angle θ based on the swing wing parameters: The formula for the hydrodynamic angle θ is: θ = arctan(U / V). Substitute the parameters in step (1) into the above formula to obtain the hydrodynamic angle θ, with the unit of rad; (3) Determine the angle of attack α of the deformed flexible swing wing and obtain the deformation amount d at the tail of the swing wing: According to the formulas β = θ - α and d = βc, substitute the determined angle of attack α of the deformed flexible swing wing and the hydrodynamic angle θ in step (2) into the above formulas to obtain the deformation amount d at the tail of the swing wing, with the unit of m, and the angle of attack α of the deformed flexible swing wing, with the unit of rad; (4) Calculate the force F on the flexible swing wing: According to the formula F = 2παρ(U 2 +V 2 )hc / 2, substitute the parameters in step (1) and step (3) into the above formula to obtain the force F on the flexible swing wing, with the unit of N; (5) Determine the elastic modulus of the flexible swing wing and the number of parallel beam holes 3 to obtain the ratio of the length L1 of the parallel beam hole 3 to the thickness t1 from the parallel beam hole 3 to the edge of the flexible swing wing: Design the elastic modulus E of the flexible swing wing, with the unit of MPa, and design the number of parallel beams as N. According to the relationship It can be obtained that Substitute the elastic modulus E of the flexible swing wing, the number of designed parallel beams N, the span h in step (1), the deformation d of the swing wing tail in step (3), and the force F on the flexible swing wing in step (5) into the above formula to obtain the ratio of the length of the parallel beam hole 3 (L1) to the thickness from the parallel beam hole 3 to the edge of the flexible swing wing (t1); (5) Obtain the thickness t1 from the parallel beam hole 3 to the edge of the flexible swing wing, the length L1 of the parallel beam hole 3, the thickness of the supporting partition between the two parallel beam holes 3, and the distance b1 between the parallel beam hole 3 and the driving rod 2: The design requires that the thickness t1 from the parallel beam hole 3 to the edge of the flexible swing wing is not less than 0.5% of the chord length c. According to the value of the chord length c in step (1), the value of t1 is determined. Then, according to the ratio of the length L1 of the parallel beam hole 3 obtained in step (4) to the thickness t1 from the parallel beam hole 3 to the edge of the flexible swing wing, the length of the parallel beam hole 3 is obtained as L1. , the design requirement is b1 ≥ 2t1. Therefore, the value of b1 is determined according to the thickness t1 from the parallel beam hole 3 to the edge of the flexible swing wing. Finally, the thickness t1 from the parallel beam hole 3 to the edge of the flexible swing wing, the length L1 of the parallel beam hole 3, the thickness of the supporting diaphragm between the two parallel beam holes 3, and the distance b1 between the parallel beam hole 3 and the driving rod 2 are obtained. The units of the thickness t1 from the parallel beam hole 3 to the edge of the flexible swing wing, the length L1 of the parallel beam hole 3, the thickness of the supporting diaphragm between the two parallel beam holes 3, and the distance b1 between the parallel beam hole 3 and the driving rod 2 are all in mm; (6) Wrapping the reinforcing fiber layer 5 and the flexible material sealing layer 4: The flexible material sealing layer 4 is bonded to both end surfaces of the flexible swing wing body 1. The flexible material sealing layer 4 covers the both end surfaces of the flexible swing wing body 1 to seal the parallel beam hole 3. The wing surface of the flexible swing wing body 1 is wrapped with the reinforcing fiber layer 5; (7) Inflation inside parallel beam hole 3: pressurize and inflate the inside of parallel beam hole 3 to balance the external water pressure.

[0032] Furthermore, in step (6), the thickness of the flexible material sealing layer is 1.5%-2.5% of the chord length, and the thickness of the reinforcing fiber layer is 1.5%-2.5% of the chord length; Furthermore, in step (7), the internal air pressure of the parallel beam holes is the same as the external water pressure, which is used to balance the external water pressure and prevent the parallel beam holes from being sunken due to the water pressure.

[0033] The design ideas of this patent are as follows: like Figure 7 As shown, the existing parallel beam structure includes two fixed ends, an upper beam and a lower beam are connected in parallel between the two fixed ends, and parallel beam holes are formed between the upper beam, the lower beam and the two fixed ends.

[0034] for Figure 7In the parallel beam structure shown, when the left side is fixed and an upward force is applied to the right side, since the force is applied equally to the two beams, the two beams deform in the same way and are in an approximately parallel state; the left and right supporting structures are treated as non-deformed and are therefore also nearly parallel, so the structure is generally called a parallel beam structure, with parallel beam holes inside.

[0035] From the perspective of a single beam, its deformation is antisymmetric, so there is no bending moment in the middle. Therefore, it can be regarded as an antisymmetric cantilever beam (i.e., cantilever beams represented by different colors). It is subjected to a single concentrated force, and the magnitude of the force is half of F, that is, F / 2. According to material mechanics, the general formula for the deformation of a cantilever beam subjected to a concentrated force at its end is: In this patent, the length of the parallel beam hole is defined as L1, that is, the cantilever beam length is L1 / 2; the overall force on the flexible wing is F. Since the force is transferable, and it is approximately assumed that the overall force of each parallel beam hole is the same, it is evenly divided on the cantilever beam, and the force is F / 2; the deformation of the parallel beam hole is twice that of a single cantilever beam, that is, d=2y; the parallel beam is a rectangular beam with a cross-sectional width equal to the span, h, and a thickness of t1. Therefore, its moment of inertia is: Substituting the above variables into the general deformation formula of cantilever beam, we get: Conversely, we can get: Regarding the force on the airfoil in this patent, the general lift formula for the airfoil can be expressed as: Where CL is the lift coefficient and S is the airfoil projected area. Since the flexibility is constantly deforming, the lift coefficient is difficult to calculate. In this patent, it is simplified to a flat plate analysis. According to the airfoil theory, the lift coefficient of the flat plate can be expressed as: In the above formula: α is the radian of the angle of attack.

[0036] In this patent, the square of the speed of the swing wing is the square of the total speed, which can be expressed as U according to the vector relationship. 2 +V 2 ; Its projected area is the airfoil span × airfoil chord length, i.e. hc; Therefore, the airfoil force can be expressed as: Thus the calculation formula of this patent is obtained.

[0037] Therefore, an embodiment of the design method is as follows: (1) Determine the parameters of the swing wing: design the swing wing chord length c = 0.5 m, span h = 2 m, forward speed V = 1 m / s, and design the heave speed U = 0.5 m / s at the middle position of the heave motion; (2) Calculate the hydrodynamic angle θ based on the flap parameters: The formula for the hydrodynamic angle θ is: θ = arctan (U / V). Substitute the parameters in step (1) into the above formula, and the hydrodynamic angle θ = arctan (U / V) = 0.46 rad; (3) Determine the attack angle α of the flexible swing wing after deformation and calculate the deformation d of the swing wing tail: According to the formula β=θ-α and the formula d=βc, the attack angle α=8°=0.14rad of the flexible swing wing after deformation and the hydrodynamic angle θ in step (2) are substituted into the above formula to obtain β=θ-α=0.32rad, and then the deformation d=βc=0.16m; (4) Calculate the force F on the flexible flap: According to the formula F = 2παρ(U 2 +V 2 )hc / 2, and the parameters in step (1) and step (3) are substituted into the above formula to obtain the force on the flexible flap F=2παρ(U 2 +V 2 )hc / 2=550N (rounded up), the value of ρ above is 1000 kg / m³; (5) Determine the elastic modulus of the flexible swing wing and the number of parallel beam holes 3 to obtain the ratio of the length of the parallel beam hole 3 (L1) to the thickness from the parallel beam hole 3 to the edge of the flexible swing wing (t1): The elastic modulus of the flexible swing wing is designed to be E = 100 MPa, the number of parallel beams is N = 2, According to the relationship Available Substitute the elastic modulus E of the flexible swing wing, the number of designed parallel beams N, the span h in step (1), the deformation d of the swing wing tail in step (3), and the force F on the flexible swing wing in step (5) into the above formula, and the ratio of the length of the parallel beam hole 3 (L1) to the thickness from the parallel beam hole 3 to the edge of the flexible swing wing (t1) is obtained to be 39 (rounded up). (5) Obtain the thickness t1 of the parallel beam hole 3 to the edge of the flexible swing wing, the length L1 of the parallel beam hole 3, the thickness of the supporting partition between the two parallel beam holes 3, and the distance b1 between the parallel beam hole 3 and the driving rod 2: The design requires that the thickness t1 of the parallel beam hole 3 to the edge of the flexible swing wing should not be less than 0.5% of the chord length c. According to the value of the chord length c in step (1), the value of t1 is determined. Then, according to the ratio of the length L1 of the parallel beam hole 3 obtained in step (4) to the thickness t1 of the parallel beam hole 3 to the edge of the flexible swing wing, the length L1 of the parallel beam hole 3 to the edge of the flexible swing wing is determined. The design requires b1 ≥ 2t1. Therefore, according to the thickness t1 of the parallel beam hole 3 to the edge of the flexible swing wing, the value of b1 is determined. Finally, the thickness t1 of the parallel beam hole 3 to the edge of the flexible swing wing, the length L1 of the parallel beam hole 3, the thickness of the supporting partition between the two parallel beam holes 3, and the distance b1 between the parallel beam hole 3 and the driving rod 2 are obtained. Take t1 = 0.5% c = 2.5 mm, then L1 = 97 mm (rounded). Design b1=4t1=10mm; (6) Wrapping the reinforcing fiber layer 5 and the flexible material sealing layer 4: The flexible material sealing layer 4 is bonded to both end surfaces of the flexible swing wing body 1. The flexible material sealing layer 4 covers the both end surfaces of the flexible swing wing body 1 to seal the parallel beam hole 3. The wing surface of the flexible swing wing body 1 is wrapped with the reinforcing fiber layer 5; (7) Inflation inside parallel beam hole 3: pressurize and inflate the inside of parallel beam hole 3 to balance the external water pressure.

[0038] In step (6), the thickness of the flexible material sealing layer is 1.5%-2.5% of the chord length, taking 0.01m, and the thickness of the reinforced fiber layer is 1.5%-2.5% of the chord length, taking 0.01m; In step (7), the internal air pressure of the parallel beam hole is the same as the external water pressure, which is used to balance the external water pressure and prevent the parallel beam hole from being sunken due to the water pressure.

[0039] The above-mentioned flexible material can be made of rubber or silicone, the flexible material sealing layer 4 is made of rubber or silicone, the reinforcing fiber layer 5 is a fabric formed by reinforcing fiber structure of organic fiber or inorganic fiber attached to the surface of the flexible swing wing body 1, the above-mentioned driving rod 2 and the driving rod mounting hole on the flexible swing wing plate are designed to be a special-shaped structure, the special-shaped structure can be Figure 1 and Figure 2 The special-shaped structure in Figure 3-Figure 6The special-shaped structure in the invention increases the connection area between the driving rod 2 and the swing wing, provides sufficient rigidity for the front part of the swing wing, improves the bonding force, and wraps the surface with a reinforcing fiber layer 5 to improve fatigue resistance under large deformation conditions without affecting the operation of the parallel beam. Due to the adoption of the above-mentioned structure and method, based on the S-shaped deformation law of the parallel beam, when the flexible swing wing is subjected to hydrodynamic force, more deformation occurs at a position close to the front half of the airfoil, forming a certain angle of attack, while the rear half of the wing maintains a smaller deformation, thereby allowing the flexible swing wing to maintain a better hydrodynamic geometric shape and improve the hydrodynamic performance. It has the advantages of simple structure, utilizing the deformation characteristics of the parallel beam to control the deformation law of the flexible swing wing, thereby improving the hydrodynamic performance of the flexible swing wing, etc.

Claims

1. A flexible swing wing of an underwater bionic propulsion system, provided with a flexible swing wing body, characterized in that The front end of the flexible wing body is provided with a driving rod mounting hole. A driving rod is inserted into the driving rod mounting hole. At least two parallel beam holes are provided on the flexible wing body behind the driving rod mounting hole.

2. The flexible swing wing of the underwater bionic propulsion device according to claim 1 is characterized in that Flexible material sealing layers are provided on both end faces of the flexible wing body. The flexible material sealing layers cover both end faces of the flexible wing body to seal the parallel beam holes.

3. The flexible swing wing of the underwater bionic propulsion device according to claim 1 is characterized in that The wing surface of the flexible wing body is wrapped with a reinforcing fiber layer to prevent tearing when the parallel beam holes of the flexible wing deform.

4. The flexible swing wing of the underwater bionic propulsion device according to claim 1 is characterized in that The driving rod mounting hole is designed as a special-shaped hole. The part of the driving rod inserted into the driving rod mounting hole fits with the special-shaped hole, increasing the connection area between the driving rod and the wing, providing sufficient rigidity for the front part of the wing, improving the adhesion force. The part of the driving rod extending out of the driving rod mounting hole at one end is cylindrical for easy connection with the driver.

5. The flexible swing wing of the underwater bionic propulsion device according to claim 1 is characterized in that The driving rod is arranged within the range of the leading edge L of the wing, where 0.1c < L < 0.2c, and c is the chord length. The minimum thickness t0 of the flexible material on the outer edge of the driving rod is not less than 1% of the chord length c.

6. The flexible swing wing of the underwater bionic propulsion device according to claim 1 is characterized in that The length of the parallel beam hole is L1. The thickness from the parallel beam hole to the edge of the flexible wing is t1, and t1 is not less than 0.5% of the chord length c. The thickness of the support partition between the two parallel beam holes is b1, and the distance between the parallel beam hole and the driving rod is also b1, and b1 ≥ 2t1.

7. A design method for flexible swing wings of underwater bionic propulsion, characterized in that The design method steps are as follows: (1) Determine the wing parameters: Design the wing chord length c in m, design the span h in m, design the forward speed V in m / s, and design the heaving speed U at the middle position of the heaving motion in m / s. (2) Calculate the hydrodynamic angle θ based on the wing parameters: The formula for the hydrodynamic angle θ is: θ = arctan(U / V). Substitute the parameters in step (1) into the above formula to obtain the hydrodynamic angle θ in rad. (3) Determine the angle of attack α of the flexible wing after deformation and obtain the deformation amount d at the tail of the wing: According to the formulas β = θ - α and d = βc, substitute the determined angle of attack α of the flexible wing after deformation and the hydrodynamic angle θ in step (2) into the above formula to obtain the deformation amount d at the tail of the wing in m, and the angle of attack α of the flexible wing after deformation in rad. (4) Calculate the force F on the flexible flap: According to the formula F = 2παρ(U 2 +V 2 )hc / 2, substitute the parameters in step (1) and step (3) into the above formula to obtain the force F on the flexible flap, in N; (5) Determine the elastic modulus of the flexible wing and the number of parallel beam holes to obtain the ratio of the length L1 of the parallel beam hole to the thickness t1 from the parallel beam hole to the edge of the flexible wing: Design the elastic modulus E of the flexible wing in MPa, and design the number of parallel beams as N. According to the relationship It can be obtained that Substitute the elastic modulus E of the flexible wing, the designed number of parallel beams N, the span h in step (1), the deformation amount d at the tail of the wing in step (3), and the force F on the flexible wing in step (5) into the above formula to obtain the ratio of the length L1 of the parallel beam hole to the thickness t1 from the parallel beam hole to the edge of the flexible wing. (5) Obtain the thickness t1 from the parallel beam hole to the edge of the flexible swing wing, the length L1 of the parallel beam hole, the thickness of the supporting partition between the two parallel beam holes, and the distance b1 between the parallel beam hole and the driving rod: The design requires that the thickness t1 from the parallel beam hole to the edge of the flexible swing wing is not less than 0.5% of the chord length c. According to the value of the chord length c in step (1), the value of t1 is taken. Then, according to the ratio of the length L1 of the parallel beam hole obtained in step (4) to the thickness t1 from the parallel beam hole to the edge of the flexible swing wing, the length of the parallel beam hole is obtained as L.

1. The design requirement is b1 ≥ 2t1. Therefore, the value of b1 is determined based on the thickness t1 from the parallel beam hole to the edge of the flexible swing wing. The final values ​​are the thickness t1 from the parallel beam hole to the edge of the flexible swing wing, the length L1 of the parallel beam hole, the thickness of the supporting diaphragm between the two parallel beam holes, and the distance b1 between the parallel beam hole and the driving rod. The units of the thickness t1 from the parallel beam hole to the edge of the flexible swing wing, the length L1 of the parallel beam hole, the thickness of the supporting diaphragm between the two parallel beam holes, and the distance b1 between the parallel beam hole and the driving rod are all in mm. (6) Wrapping the reinforcing fiber layer and the flexible material sealing layer: bonding the flexible material sealing layer to the two end surfaces of the flexible swing wing body, the flexible material sealing layer covers the two end surfaces of the flexible swing wing body to seal the parallel beam holes, and the wing surface of the flexible swing wing body is wrapped with the reinforcing fiber layer; (7) Inflation inside the parallel beam hole: pressurize and inflate the inside of the parallel beam hole to balance the external water pressure.

8. The method for designing a flexible swing wing of an underwater bionic propulsion system according to claim 7, characterized in that In the step (6), the thickness of the flexible material sealing layer is 1.5%-2.5% of the chord length, and the thickness of the reinforcing fiber layer is 1.5%-2.5% of the chord length.

9. The method for designing a flexible swing wing of an underwater bionic propulsion system according to claim 7, characterized in that In step (7), the internal air pressure of the parallel beam hole is the same as the external water pressure, which is used to balance the external water pressure and prevent the parallel beam hole from being sunken due to the water pressure.

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