Nonlinear stiffness underwater glider for wave-propelled unmanned ship

Abstract

The invention provides a non-linear rigidity underwater glider for a wave-propelled unmanned ship, which comprises a plurality of non-linear rigidity hydrofoils 1, a glider main body 2 and an auxiliary steering part 3, the plurality of non-linear rigidity hydrofoils 1 are fixed on the glider main body 2 in a horizontal array, and the auxiliary steering part 3 is mounted at the tail end of the glider main body 2. The non-linear rigidity hydrofoil 1 can form the double-well potential energy characteristic, large-amplitude inter-well oscillation can be effectively induced under the low wave frequency, the phase between the rotating angle of the non-linear rigidity hydrofoil 1 and fluid exciting force is adjusted, the propelling efficiency is improved, and the auxiliary steering part 3 is used for auxiliary propelling and steering of the non-linear rigidity underwater glider. The invention further provides a wave-propelled unmanned ship, the wave-propelled unmanned ship comprises the non-linear rigidity underwater glider and further comprises an unmanned ship body 4 and an umbilical cable part 5, and the non-linear rigidity underwater glider is used for converting up-and-down fluctuating motion of waves into advancing thrust of a ship body.

Description

Technical Field

[0001] This invention belongs to the field of marine unmanned vehicle technology, specifically relating to a nonlinear stiffness underwater glider for wave-propelled unmanned vessels. Background Technology

[0002] Wave-propelled unmanned surface vessels (USVs), as a novel type of marine observation platform, have become an important development direction for long-range, deep-sea environmental monitoring due to their theoretically near-infinite endurance. Their core principle is to convert the up-and-down motion of waves into forward thrust using the hull or attached hydrofoil mechanisms. Among these, hydrofoil-based wave propulsion technology has attracted widespread attention due to its high efficiency. This type of technology typically involves installing one or more hydrofoils underwater, connected to the hull via an umbilical or linkage mechanism. When waves cause the hull to heave, they drive the hydrofoils to perform periodic pitching motions in the vertical plane. Most wave-propelled hydrofoils employ a passive design; however, in the complex and ever-changing real-world marine environment, the hydrofoil connections are usually based on linear stiffness elements such as linear springs or torsion bars, resulting in low energy capture efficiency in such linear systems. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing linear stiffness hydrofoil propulsion devices in terms of insufficient energy capture efficiency under low-frequency sea conditions, and to propose a nonlinear stiffness underwater glider for wave-propelled unmanned surface vessels. This structure, through a nonlinear stiffness mechanism formed by the synergy of compression and tension springs, can generate a double-well potential energy characteristic, effectively inducing large-amplitude inter-well oscillations at lower wave frequencies, thus significantly improving energy capture and propulsion efficiency.

[0004] The technical solution of this invention is:

[0005] A nonlinear stiffness underwater glider for wave-propelled unmanned surface vessels includes a nonlinear stiffness hydrofoil 1, a glider body 2, and an auxiliary steering unit 3. Multiple nonlinear stiffness hydrofoils 1 are horizontally arrayed and fixed to the glider body 2. The auxiliary steering unit 3 is installed at the tail end of the glider body 2. The nonlinear stiffness hydrofoils 1 can form a double-well potential energy characteristic, effectively inducing large-amplitude inter-well oscillations at lower wave frequencies, adjusting the phase between the rotation angle of the nonlinear stiffness hydrofoils 1 and the fluid excitation force, thereby improving propulsion efficiency. The auxiliary steering unit 3 is used for auxiliary propulsion and steering of the nonlinear stiffness underwater glider.

[0006] The glider body 2 is a hollow cuboid shape with an arc-shaped head at its front end. Multiple receiving through holes 21 are provided in the horizontal direction of the glider body 2. Symmetrical arc-shaped grooves 22 are provided around the periphery of each receiving through hole 21. The center of the concentric circle of the arc-shaped grooves 22 coincides with the center of the receiving through hole 21.

[0007] The nonlinear stiffness hydrofoil 1 includes a nonlinear stiffness spring system 11 and two wings 12. The two wings 12 are symmetrically arranged on both sides of the nonlinear stiffness spring system 11. The nonlinear stiffness spring system 11 is disposed in the receiving through hole 21 of the glider body 2. The two wings 12 are respectively located on both sides of the glider body 2. Each wing 12 consists of a hollow wing 121, a fixing plate 122, and a fixing ring 123. The fixing plate 122 is inserted into one side of the hollow wing 121 and bolted to it. The fixing ring 123 is disposed on one side of the fixing plate 122 and is used to receive the nonlinear stiffness spring system 11.

[0008] The nonlinear stiffness spring system 11 includes a compression spring 111, a compression spring fixing part 112, a connecting shaft 113, a sleeve fixing ring 114, a central sleeve 115, a central bearing 116, a tension spring 117, and a tension spring positioning member 118. A central bearing 116 is respectively provided at both ends of the central sleeve 115. The central bearing 116 is fixedly disposed in the receiving through hole 21. The diameters of both ends of the central sleeve 115 are larger than the diameter of the central part, and the two central bearings 116 respectively abut against both ends of the central sleeve 115. On the inner side of the central sleeve 115, a pair of lugs 1151 are symmetrically provided at each end. The pair of lugs 1151 are distributed along the end diameter. Each lug 1151 is provided with a connecting shaft hole 11511. A raised strip 1152 is provided on the side of each end. The raised strip 1152 is also provided along the end diameter. The length of the raised strip 1152 is between the end radius and the end diameter. One end of the raised strip 1152 is close to the connecting shaft hole 11511. The raised strip 1152 is used to be inserted into the fixing ring 123.

[0009] The compression spring fixing part 112 is disposed on the front side of the central sleeve 115. The compression spring fixing part 112 includes a compression spring sleeve 1121, a guide shaft 1122, and a fixing buckle 1123. The compression spring 111 is sleeved on the guide shaft 1122. The compression spring sleeve 1121 fixes the two ends of the compression spring 111 by concentrically engaging with the fixing buckle 1123. The guide shaft 1122 is composed of a solid rod and a hollow rod nested together. Both ends of the guide shaft 1122 are provided with locking fittings to facilitate rotation with the fixing buckle 1123. The compression spring 111 is locked in place by a locking mechanism. The compression spring sleeves 1121 at both ends of the compression spring 111 are rotatably connected to a connecting shaft 113 and limited by a sleeve retaining ring 114. Both connecting shafts 113 are located in front of the central sleeve 115. The two ends of the connecting shaft 113 closest to the front of the central sleeve 115 are respectively disposed within the two connecting shaft holes 11511 of the central sleeve 115, while the connecting shaft 113 furthest from the front of the central sleeve 115 is fixedly disposed in front of the glider body 2. A connecting shaft 113 is also provided in one of the two connecting shaft holes 11511 on the rear side of the central sleeve 115. A connecting shaft 113 is also fixedly provided on the rear side of the glider body 2. Viewed from the rear side of the glider body 2, a tension spring 117 is connected between the connecting shaft 113 near the rear side of the central sleeve 115 and the connecting shaft 113 away from the rear side of the central sleeve 115. Both ends of the tension spring 117 are fixed by a tension spring positioning member 118. The two tension spring positioning members 118 are respectively located near the central sleeve 115. The connecting shaft 113 on the rear side and the connecting shaft 113 on the side away from the rear side of the central sleeve 115 are rotatably connected. The ends of the two connecting shafts 113 on the front side of the central sleeve 115 are provided with limit baffles 1131. The two connecting shafts 113 near the central sleeve 115 rotate with the rotation of the central sleeve 115. The two connecting shafts 113 away from the central sleeve 115 remain stationary because they are fixed on the glider body 2. The two connecting shafts 113 near the central sleeve 115 move in the arc groove 22 of the glider body 2 respectively.

[0010] Furthermore, the auxiliary steering unit 3 includes a tail connecting body 31, a tail fin rotating connector 32, an auxiliary steering tail fin 33, a steering shaft 34, a steering connector 35, a tail cover connecting cylinder 36, a propeller blade 37, and a propeller fairing 38. The front end of the tail connecting body 31 is swallowtail-shaped and transitionally connects to the rear end of the glider body 2. The rear end of the tail connecting body 31 has a protrusion located in the middle of the tail fin rotating connector 32 and is rotatably connected through the steering shaft 34. The tail connecting body 31 and the tail fin rotating connector 32 achieve a rotatable fit through a concave-convex structure. The tail fin rotating connector 35... 2. Rotates around the steering shaft 34. The top of the tail fin rotating connector 32 has a tail fin fixing groove. The lower end of the auxiliary steering tail fin 33 is fixed in the tail fin fixing groove. The auxiliary steering tail fin 33 is in contact with the fluid and is streamlined. The front end of the steering connector 35 is conically engaged with the tail fin rotating connector 32. The rear end of the steering connector 35 is a cylinder connected to the tail cover connecting cylinder 36. The tail cover connecting cylinder 36 has two threaded holes on its circumference for fixed connection with the propeller blades 37. The two propeller blades 37 are symmetrically installed. The propeller fairing 38 is a conical hollow structure and is connected to the tail cover connecting cylinder 36.

[0011] Also provided is a wave-propelled unmanned surface vessel (USV), including a nonlinear stiffness underwater glider for wave-propelled USV, and a USV body 4 and an umbilical cable 5. The USV body 4 navigates on the water surface, and the umbilical cable 5 connects the USV body 4 and the nonlinear stiffness underwater glider. The USV body 4 includes a vessel body 41, a marine communication and meteorological monitoring unit 42, a sensor self-powered unit 43, and a heading stabilization unit 44. The vessel body 41 has a hollow internal structure, and the marine communication and meteorological monitoring unit 42, the sensor self-powered unit 43, and the heading stabilization unit 44 are located on the surface. The stabilization unit 44 includes a sensor self-powered unit 43 comprising multiple solar panels 431 and a vessel identification plate 432. The multiple solar panels 431 are embedded in the entire upper surface of the vessel body 41. The marine communication and meteorological monitoring unit 42 is located in the middle of the upper surface. The vessel identification plate 432 is located on the side of the marine communication and meteorological monitoring unit 42. The heading stabilization unit 44 includes a tail fin 441 and a float 442. The tail fin 441 is located on the lower surface of the stern of the vessel body 41, and the float 442 is located at the stern of the vessel body.

[0012] Furthermore, the umbilical cable section 5 includes an umbilical cable 51 and umbilical connection sections 52 at both ends. The umbilical cable 51 is a flat cable. The umbilical connection section 52 connected to the unmanned vessel body 4 includes a horizontal steering component 521, a pitch steering component 522, and a pitch steering component 523 connected in sequence. The horizontal steering component 521 is connected to the unmanned vessel body 4, and the pitch steering component 523 is connected to the umbilical cable 51. The horizontal steering component 521 can rotate in the horizontal plane, the pitch steering component 522 can rotate in the pitch direction, and the pitch steering component 523 can rotate in the pitch direction. Both the unmanned vessel body 4 and the nonlinear stiffness underwater glider are provided with bosses for fixing to the umbilical connection section 52. The umbilical connection section 52 connected to the nonlinear stiffness underwater glider only includes the pitch steering component 522 and the pitch steering component 523 connected to it.

[0013] The beneficial effects of this invention are as follows:

[0014] 1. The nonlinear stiffness hydrofoil designed in this invention features a nonlinear stiffness spring system composed of compression and tension springs working in tandem, arranged on a central sleeve. This allows it to undergo either counterclockwise or clockwise "torsional" motion. Both the compression and tension springs simultaneously influence the elastic potential energy, generating nonlinear stiffness in the hydrofoil's pitch direction. Compared to traditional fixed stiffness systems, this invention can easily and effectively induce large-amplitude inter-well oscillations at lower wave frequencies, adjusting the phase between the nonlinear stiffness hydrofoil's rotation angle and the fluid excitation force, thereby improving energy capture and conversion efficiency during wave propulsion.

[0015] 2. The compression spring adopts a guiding and anti-bending design to effectively avoid compression instability. Combined with the stable force characteristics of the tension spring, the overall system still has high reliability and motion stability in complex water flow environments.

[0016] 3. This invention highly integrates a nonlinear stiffness spring system, hydrofoil, and its pitch and rotation mechanism within the unmanned underwater glider, resulting in a compact and rational structure with strong overall integrity, facilitating installation and deployment on various types of unmanned vessels. The modular design approach enhances the system's versatility and scalability while also reducing manufacturing and maintenance costs.

[0017] 4. The spring system in this invention adopts a modular design, and key elastic components can be quickly disassembled and replaced through simple connectors, which facilitates the adjustment of the system stiffness characteristics according to different situations, improves the reconfigurability and adaptability of the system to working conditions, and also facilitates maintenance and debugging. Attached Figure Description

[0018] Figure 1 This is an isometric view of the wave-propelled unmanned surface vessel with nonlinear stiffness underwater glider of the present invention.

[0019] Figure 2 This is a partial schematic diagram of the nonlinear stiffness underwater glider of the present invention.

[0020] Figure 3 This is a partial schematic diagram of the glider body of the nonlinear stiffness underwater glider of the present invention.

[0021] Figure 4 This is a schematic diagram of the nonlinear stiffness hydrofoil of the present invention.

[0022] Figure 5 This is a schematic diagram of the airfoil of the nonlinear stiffness hydrofoil of the present invention.

[0023] Figure 6 This is a schematic diagram of the nonlinear stiffness spring system of the present invention.

[0024] Figure 7 This is an exploded view of the compression spring fixing part of the present invention.

[0025] Figure 8 This is a schematic diagram of the auxiliary steering part of the present invention.

[0026] Figure 9 This is a cross-sectional view of the auxiliary steering portion of the present invention.

[0027] Figure 10 This is a schematic diagram of the main body of the unmanned vessel of the present invention.

[0028] Figure 11 This is a partial schematic diagram of the umbilical cable portion of the present invention.

[0029] Figure 12 This is a schematic diagram showing the state entity and state abbreviated of the nonlinear stiffness hydrofoil of the present invention when it is at a negative angle of attack.

[0030] Figure 13 This is a schematic diagram showing the state entity and state abbreviated of the nonlinear stiffness hydrofoil of the present invention when it is at zero angle of attack.

[0031] Figure 14 This is a schematic diagram showing the state entity and state abbreviated of the nonlinear stiffness hydrofoil of the present invention when it is at a positive angle of attack.

[0032] Legend:

[0033] 1. Nonlinear stiffness hydrofoil; 2. Glider body; 3. Auxiliary steering unit; 4. Unmanned surface vessel body; 5. Umbilical cable unit;

[0034] Nonlinear stiffness spring system 11, compression spring 111, compression spring fixing part 112, compression spring sleeve 1121, guide shaft 1122, fixing buckle 1123, connecting shaft 113, limit stop 1131, sleeve fixing ring 114, center sleeve 115, lug 1151, connecting shaft hole 11511, protruding strip 1152, center bearing 116, tension spring 117, tension spring positioning part 118, wing 12, hollow wing 121, fixing insert plate 122, fixing ring 123;

[0035] Accommodating through-hole 21 and arc-shaped groove 22;

[0036] Tail connecting body 31, tail fin rotating connector 32, auxiliary steering tail fin 33, steering shaft 34, steering connector 35, tail cover connecting cylinder 36, propeller blade 37, propeller fairing 38.

[0037] 41. Main body of the vessel; 42. Marine communication and meteorological monitoring unit; 43. Sensor self-powered unit; 431. Solar panel; 432. Vessel identification plate; 44. Heading stabilization unit; 441. Tail fin; 442. Float unit.

[0038] 51. Umbilical cable, 52. Umbilical connection, 521. Horizontal steering component, 522. Pitch steering component, 523. Detailed Implementation

[0039] The invention will now be further described with reference to the accompanying drawings.

[0040] like Figure 1 A nonlinear stiffness underwater glider for wave-propelled unmanned surface vessels includes a nonlinear stiffness hydrofoil 1, a glider body 2, and an auxiliary steering unit 3. Multiple nonlinear stiffness hydrofoils 1 are horizontally arrayed and fixed to the glider body 2. The auxiliary steering unit 3 is installed at the tail end of the glider body 2. The nonlinear stiffness hydrofoils 1 can form a double-well potential energy characteristic, effectively inducing large-amplitude inter-well oscillations at lower wave frequencies, adjusting the phase between the rotation angle of the nonlinear stiffness hydrofoils 1 and the fluid excitation force, thereby improving propulsion efficiency. The auxiliary steering unit 3 is used for auxiliary propulsion and steering of the nonlinear stiffness underwater glider.

[0041] like Figure 2-3 The glider body 2 is a hollow cuboid shape with an arc-shaped head at its front end. Multiple receiving through holes 21 are provided in the horizontal direction of the glider body 2. Symmetrical arc-shaped grooves 22 are provided around the periphery of each receiving through hole 21. The center of the concentric circle of the arc-shaped grooves 22 coincides with the center of the receiving through hole 21.

[0042] like Figure 4-5The nonlinear stiffness hydrofoil 1 includes a nonlinear stiffness spring system 11 and two wing sections 12. The two wing sections 12 are symmetrically arranged on both sides of the nonlinear stiffness spring system 11. The nonlinear stiffness spring system 11 is disposed in the receiving through hole 21 of the glider body 2. The two wing sections 12 are respectively located on both sides of the glider body 2. Each wing section 12 consists of a hollow wing 121, a fixing plate 122, and a fixing ring 123. The fixing plate 122 is inserted into one side of the hollow wing 121 and bolted to it. The fixing ring 123 is disposed on one side of the fixing plate 122 and is used to receive the nonlinear stiffness spring system 11.

[0043] like Figure 6 The nonlinear stiffness spring system 11 includes a compression spring 111, a compression spring fixing part 112, a connecting shaft 113, a sleeve fixing ring 114, a central sleeve 115, a central bearing 116, a tension spring 117, and a tension spring positioning member 118. A central bearing 116 is respectively provided at both ends of the central sleeve 115. The central bearing 116 is fixedly disposed in the receiving through hole 21. The diameters of both ends of the central sleeve 115 are larger than the diameter of the central part, and the two central bearings 116 respectively abut against both ends of the central sleeve 115. On the inner side of the central sleeve 115, a pair of lugs 1151 are symmetrically provided at each end. The pair of lugs 1151 are distributed along the end diameter. Each lug 1151 is provided with a connecting shaft hole 11511. A raised strip 1152 is provided on the side of each end. The raised strip 1152 is also provided along the end diameter. The length of the raised strip 1152 is between the end radius and the end diameter. One end of the raised strip 1152 is close to the connecting shaft hole 11511. The raised strip 1152 is used to be inserted into the fixing ring 123.

[0044] like Figure 7The compression spring fixing part 112 is disposed on the front side of the central sleeve 115. The compression spring fixing part 112 includes a compression spring sleeve 1121, a guide shaft 1122, and a fixing buckle 1123. The compression spring 111 is sleeved on the guide shaft 1122. The compression spring sleeve 1121 fixes the two ends of the compression spring 111 by concentrically engaging with the fixing buckle 1123. The guide shaft 1122 is composed of a solid rod and a hollow rod nested together. Both ends of the guide shaft 1122 are provided with locking fittings to facilitate engagement with the fixing buckle 1123. The compression spring 111 is rotated to engage and engage with the compression spring sleeves 1121 at both ends of the compression spring 111. These sleeves are rotatably connected to a connecting shaft 113 and are limited by a sleeve retaining ring 114. Both connecting shafts 113 are located in front of the central sleeve 115. The two ends of the connecting shaft 113 closest to the front of the central sleeve 115 are respectively disposed within the two connecting shaft holes 11511 of the central sleeve 115, while the connecting shaft 113 furthest from the front of the central sleeve 115 is fixedly disposed in front of the glider body 2. A connecting shaft 113 is also provided in one of the two connecting shaft holes 11511 on the rear side of the central sleeve 115. A connecting shaft 113 is also fixedly provided on the rear side of the glider body 2. Viewed from the rear side of the glider body 2, a tension spring 117 is connected between the connecting shaft 113 near the rear side of the central sleeve 115 and the connecting shaft 113 away from the rear side of the central sleeve 115. Both ends of the tension spring 117 are fixed by a tension spring positioning member 118. The two tension spring positioning members 118 are respectively located near the central sleeve 115. The connecting shaft 113 on the rear side and the connecting shaft 113 on the side away from the rear side of the central sleeve 115 are rotatably connected. The ends of the two connecting shafts 113 on the front side of the central sleeve 115 are provided with limit baffles 1131. The two connecting shafts 113 near the central sleeve 115 rotate with the rotation of the central sleeve 115. The two connecting shafts 113 away from the central sleeve 115 remain stationary because they are fixed on the glider body 2. The two connecting shafts 113 near the central sleeve 115 move in the arc groove 22 of the glider body 2 respectively.

[0045] Furthermore, such as Figure 8-9The auxiliary steering unit 3 includes a tail connecting body 31, a tail fin rotating connector 32, an auxiliary steering tail fin 33, a steering shaft 34, a steering connector 35, a tail cover connecting cylinder 36, a propeller blade 37, and a propeller fairing 38. The front end of the tail connecting body 31 is swallowtail-shaped and transitions to the rear end of the glider body 2. The rear end of the tail connecting body 31 has a protrusion located in the middle of the tail fin rotating connector 32 and is rotatably connected through the steering shaft 34. The tail connecting body 31 and the tail fin rotating connector 32 achieve a rotatable fit through a concave-convex structure. The tail fin rotating connector 32 surrounds... Rotating around the steering shaft 34, the top of the tail fin rotating connector 32 has a tail fin fixing groove, the lower end of the auxiliary steering tail fin 33 is fixed in the tail fin fixing groove, the auxiliary steering tail fin 33 is in contact with the fluid and is streamlined, the front end of the steering connector 35 is conically engaged with the tail fin rotating connector 32, the rear end of the steering connector 35 is a cylinder connected to the tail cover connecting cylinder 36, the tail cover connecting cylinder 36 has two threaded holes on its circumference for fixed connection with the propeller blades 37, the two propeller blades 37 are symmetrically installed, the propeller fairing 38 is a conical hollow structure and is connected to the tail cover connecting cylinder 36.

[0046] like Figure 1 and Figure 10 The invention also provides a wave-propelled unmanned surface vessel (USV), including a nonlinear stiffness underwater glider for wave propulsion, a USV body 4, and an umbilical cable 5. The USV body 4 navigates on the water surface, and the umbilical cable 5 connects the USV body 4 and the nonlinear stiffness underwater glider. The USV body 4 includes a vessel body 41, a marine communication and meteorological monitoring unit 42, a sensor self-powered unit 43, and a heading stabilization unit 44. The vessel body 41 has a hollow internal structure, and the marine communication and meteorological monitoring unit 42, the sensor self-powered unit 43, and the heading stabilization unit 44 are located on the surface. The stabilization unit 44 includes a sensor self-powered unit 43 comprising multiple solar panels 431 and a vessel identification plate 432. The multiple solar panels 431 are embedded in the entire upper surface of the vessel body 41. The marine communication and meteorological monitoring unit 42 is located in the middle of the upper surface. The vessel identification plate 432 is located on the side of the marine communication and meteorological monitoring unit 42. The heading stabilization unit 44 includes a tail fin 441 and a float 442. The tail fin 441 is located on the lower surface of the stern of the vessel body 41, and the float 442 is located at the stern of the vessel body.

[0047] Furthermore, such as Figure 11The umbilical cable section 5 includes an umbilical cable 51 and umbilical connection sections 52 at both ends. The umbilical cable 51 is a flat cable. The umbilical connection section 52 connected to the unmanned vessel body 4 includes a horizontal steering component 521, a pitch steering component 522, and a pitch steering component 523 connected in sequence. The horizontal steering component 521 is connected to the unmanned vessel body 4, and the pitch steering component 523 is connected to the umbilical cable 51. The horizontal steering component 521 can rotate in the horizontal plane, the pitch steering component 522 can rotate in the pitch direction, and the pitch steering component 523 can rotate in the pitch direction. Both the unmanned vessel body 4 and the nonlinear stiffness underwater glider are provided with bosses for fixing to the umbilical connection section 52. The umbilical connection section 52 connected to the nonlinear stiffness underwater glider only includes the pitch steering component 522 and the pitch steering component 523 connected to it.

[0048] The working process of this invention is as follows:

[0049] When waves cause the unmanned vessel body 4 to heave, the umbilical cable 5 transmits the motion excitation in the direction of heave to the underwater glider, which also heaves. Simultaneously, the underwater glider drives the nonlinear stiffness hydrofoil 1 to perform periodic pitching motion in the vertical plane, thus propelling the unmanned vessel body 4 forward. Regardless of whether the waves cause the unmanned vessel body 4 to rise or fall, the nonlinear stiffness hydrofoil 1 of the underwater glider, through continuous rotation (i.e., changes in angle of attack), consistently converts this vertical motion into forward thrust.

[0050] like Figure 12 , Figure 13 and Figure 14 These are the physical and simplified schematic diagrams of the array nonlinear stiffness hydrofoil 1 of the underwater glider when it is at a negative angle of attack, a zero angle of attack, and a positive angle of attack. Figure 12 As the underwater glider moves upward under the heave of the unmanned vessel's main body 4, the hollow wing 121 also moves upward. Simultaneously, the leading edge of the hollow wing 121 rotates downward, and the hollow wing 121 faces the oncoming flow at a negative angle of attack. At this time, the nonlinear stiffness hydrofoil 1 is equivalent to a counter-clockwise "torsion". Figure 14 As the underwater glider moves downwards under the heave of the unmanned vessel's main body 4, the hollow wing 121 also moves downwards, and its leading edge rotates upwards. The hydrofoil 41 faces the oncoming flow at a positive angle of attack. At this moment, the nonlinear stiffness hydrofoil 1 is equivalent to a clockwise "torsion". The heave motion of the underwater glider is approximately sinusoidal. When the hollow wing 121 rotates to the midpoint of a pitch cycle, it faces the oncoming flow at zero angle of attack.

[0051] When the hollow wing 121 rotates, the hollow wing 121, the fixed insert plate 42, the fixed ring 43 and the central sleeve 115 rotate as a whole. The relative rotation between the whole and the glider body 2 is achieved by the central bearing 116. Under the action of water, the whole rotates around the central axis of the central sleeve 115, wherein the rotation angle of the hollow wing 121 and the central sleeve 115 is the same.

[0052] Specifically, the two connecting shafts 113, which are far from the central sleeve 115, are fixed to the glider body 2. When the hollow wing 121 rotates, they remain fixed. The sleeve fixing ring 114 fixes the compression spring sleeve 1121. During the rotation of the hollow wing 121, the compression spring sleeve 1121 and its connecting shaft 113 rotate relative to each other, with the rotation angle being the same as the rotation angle of the hollow wing 121. During the rotation, the center line of the compression spring 111 always coincides with the center line of the guide shaft 1122. The two connecting shafts 113, which are close to the central sleeve 115, rotate in the arc groove 22 of the glider body 2 as the hollow wing 121 rotates, rotating around the central axis of the central sleeve 115 by the same angle. The tension spring positioning piece 118 also rotates relative to the connecting shaft 113 during the rotation of the hollow wing 121, with the rotation angle being the same as the rotation angle of the hollow wing 121. During the rotation of the hollow wing 121, such as from zero angle of attack to negative angle of attack, the compression spring 111 on the leading edge of the hollow wing 121 is stretched diagonally downwards as its connecting shaft 113 rotates counterclockwise. The compression spring 111 goes from a compressed state to its original length and then to a stretched state. The compression spring 111 releases and stores elastic potential energy. At the same time, the extension spring 117 on the trailing edge of the hollow wing 121 is stretched diagonally upwards as its connecting shaft 113 rotates counterclockwise. The extension spring 117 maintains the stretched state from the initial stretched state and continues to store elastic potential energy. The entire nonlinear stiffness hydrofoil 1 is similar to a counterclockwise "torsional" motion. The compression spring 111 and the extension spring 117 twist around the central sleeve 115 at the same angle. The compression spring 111 and the extension spring 117 simultaneously affect the elastic potential energy. Similarly, for example, when switching from zero angle of attack to a positive angle of attack, the compression spring 111 on the leading edge of the hollow wing 121 is stretched obliquely upwards as its connecting shaft 113 rotates clockwise. The compression spring 111 goes from a compressed state to its original length and then to a stretched state. The compression spring 111 releases and stores elastic potential energy. At the same time, the extension spring 117 on the trailing edge of the hollow wing 121 is stretched obliquely downwards as its connecting shaft 113 rotates clockwise. The extension spring 117 goes from an initial stretched state and further maintains the stretched state. The extension spring 117 continuously stores elastic potential energy. By harnessing the elastic potential energy, the entire nonlinear stiffness hydrofoil 1 undergoes a clockwise "torsional" motion. The compression spring 111 and the tension spring 117 twist around the central sleeve 115 at the same angle. The compression spring 111 and the tension spring 117 simultaneously affect the elastic potential energy, which can effectively induce large-amplitude inter-trap oscillations at lower wave frequencies. Compared with traditional fixed stiffness systems, it adjusts the phase between the hydrofoil rotation angle and the fluid excitation force, thereby improving the energy capture and conversion efficiency of wave energy into kinetic energy, providing continuous and efficient power for unmanned vessels.

[0053] The specific embodiments described above are used to explain and illustrate the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the scope of protection of the present invention and the claims shall fall within the scope of protection of the present invention.

Claims

1. A nonlinear-stiffness underwater glider for wave-propelled unmanned ships, characterized in that: The device comprises a nonlinear stiffness hydrofoil (1), a glider body (2), and an auxiliary steering part (3). The nonlinear stiffness hydrofoil (1) is horizontally arrayed and fixed on the glider body (2), and the auxiliary steering part (3) is installed at the tail end of the glider body (2). The nonlinear stiffness hydrofoil (1) can form a double-trap potential characteristic, effectively induce large inter-trap oscillation at a low wave frequency, adjust the phase between the turning angle of the nonlinear stiffness hydrofoil (1) and the fluid excitation force, and improve the propulsion efficiency. The auxiliary steering part (3) is used for auxiliary propulsion and steering of the nonlinear stiffness underwater glider. The glider body (2) is in the shape of a hollow cuboid, and an arc-shaped head is arranged at the front end of the glider body (2). A plurality of containing through holes (21) are arranged in the horizontal direction of the glider body (2), and symmetric arc-shaped grooves (22) are arranged around each containing through hole (21). The center of the concentric circle where the arc-shaped grooves (22) are located coincides with the center of the containing through hole (21). The nonlinear stiffness hydrofoil (1) comprises a nonlinear stiffness spring system (11) and two wing parts (12). The two wing parts (12) are symmetrically arranged on both sides of the nonlinear stiffness spring system (11). The nonlinear stiffness spring system (11) is arranged in the containing through hole (21) of the glider body (2), and the two wing parts (12) are respectively arranged on both sides of the glider body (2). The wing part (12) is composed of a hollow wing (121), a fixed plug plate (122), and a fixed ring (123). The fixed plug plate (122) is inserted into one side of the hollow wing (121) and is bolted with the hollow wing (121). The fixed ring (123) is arranged on one side of the fixed plug plate (122), and the fixed ring (123) is used for receiving the nonlinear stiffness spring system (11). The nonlinear stiffness spring system (11) comprises a compression spring (111), a compression spring fixing part (112), a connecting shaft (113), a sleeve fixing ring (114), a center sleeve (115), a center bearing (116), a tension spring (117) and a tension spring positioning piece (118), one center bearing (116) is arranged at each end of the center sleeve (115), the center bearings (116) are fixedly arranged in the containing through hole (21), the diameters of the two end portions of the center sleeve (115) are greater than the diameter of the center portion, the two center bearings (116) abut the inner sides of the two end portions of the center sleeve (115) respectively, a pair of lugs (1151) is symmetrically arranged at each end portion of the center sleeve (115), the pair of lugs (1151) are distributed along the end portion diameter, a connecting shaft hole (11511) is arranged on each lug (1151), a protruding strip (1152) is arranged on each end portion side, the protruding strip (1152) is also arranged along the end portion diameter, the length of the protruding strip (1152) is between the end portion radius and the end portion diameter, and one end of the protruding strip (1152) is close to the connecting shaft hole (11511), and the protruding strip (1152) is used for being clamped into the fixing ring (123). The compression spring fixing part (112) is located on the front side of the central sleeve (115). The compression spring fixing part (112) includes a compression spring sleeve (1121), a guide shaft (1122), and a fixing buckle (1123). The compression spring (111) is sleeved on the guide shaft (1122). The compression spring sleeve (1121) fixes the two ends of the compression spring (111) by concentrically engaging with the fixing buckle (1123). The guide shaft (1122) is composed of a solid rod and a hollow rod nested together. The two ends of the guide shaft (1122) are provided with locking fittings to facilitate rotational engagement with the fixing buckle (1123). The compression spring (111) is clamped together; the compression spring sleeves (1121) at both ends of the compression spring (111) are respectively rotatably connected to a connecting shaft (113) and limited by a sleeve retaining ring (114). Both connecting shafts (113) are located in front of the central sleeve (115), wherein the two ends of the connecting shaft (113) closer to the front of the central sleeve (115) are respectively set in the two connecting shaft holes (11511) of the central sleeve (115), and the connecting shaft (113) away from the front of the central sleeve (115) is fixedly set in front of the glider body (2); the central sleeve A connecting shaft (113) is also provided in the two connecting shaft holes (11511) on the rear side of the cylinder (115). A connecting shaft (113) is also fixedly provided on the rear side of the glider body (2). From the rear side of the glider body (2), the connecting shaft (113) near the rear side of the central sleeve (115) and the connecting shaft (113) away from the rear side of the central sleeve (115) are connected by the tension spring (117). The two ends of the tension spring (117) are respectively fixed by a tension spring positioning member (118). The two tension spring positioning members (118) are respectively located near the rear side of the central sleeve (115). The connecting shaft (113) and the connecting shaft (113) away from the rear side of the central sleeve (115) are rotatably connected. The ends of the two connecting shafts (113) on the front side of the central sleeve (115) are provided with limit baffles (1131). The two connecting shafts (113) near the central sleeve (115) rotate with the rotation of the central sleeve (115). The two connecting shafts (113) away from the central sleeve (115) remain stationary because they are fixed on the glider body (2). The two connecting shafts (113) near the central sleeve (115) move in the arc groove (22) of the glider body (2).

2. The nonlinear-stiffness underwater glider for wave propelled unmanned ships according to claim 1, characterized in that: The auxiliary steering part (3) comprises a tail connecting body (31), a tail fin rotating connecting piece (32), an auxiliary steering tail fin (33), a steering rotating shaft (34), a steering connecting piece (35), a tail cover connecting cylinder (36), propeller blades (37) and a propeller fairing (38), the front end of the tail connecting body (31) is dovetail-shaped, and is transitionally connected with the rear end of the glider body (2), the rear end of the tail connecting body (31) is provided with a protrusion, the protrusion is located in the middle of the tail fin rotating connecting piece (32) and is rotationally connected through the steering rotating shaft (34), the tail connecting body (31) and the tail fin rotating connecting piece (32) are rotationally matched through concave-convex structures, the tail fin rotating connecting piece (32) rotates around the steering rotating shaft (34), the top of the tail fin rotating connecting piece (32) is provided with a tail fin fixing groove, the lower end of the auxiliary steering tail fin (33) is fixed in the tail fin fixing groove, the auxiliary steering tail fin (33) is in contact with fluid and is streamlined, the front end of the steering connecting piece (35) is conically matched with the tail fin rotating connecting piece (32), the rear end of the steering connecting piece (35) is a cylinder connected with the tail cover connecting cylinder (36), the tail cover connecting cylinder (36) is provided with two threaded holes in the circumferential surface for fixedly connecting with the propeller blades (37), two pieces of propeller blades (37) are symmetrically installed, and the propeller fairing (38) is a conical hollow structure connected with the tail cover connecting cylinder (36).

3. A wave-propelled unmanned ship, comprising the nonlinear stiffness underwater glider for the wave-propelled unmanned ship according to claim 1 or 2, and further comprising an unmanned ship body (4) and a umbilical cable part (5), wherein the unmanned ship body (4) sails on the water surface, and the umbilical cable part (5) is used for connecting the unmanned ship body (4) and the nonlinear stiffness underwater glider; the unmanned ship body (4) comprises a ship body (41), an ocean communication and weather monitoring part (42), a sensor self-power supply part (43) and a heading stabilization part (44); the ship body (41) is a hollow structure inside, and the surface is provided with the ocean communication and weather monitoring part (42), the sensor self-power supply part (43) and the heading stabilization part (44); the sensor self-power supply part (43) comprises a plurality of solar panels (431) and a ship identification plate (432), the plurality of solar panels (431) are inlaid on the entire upper surface of the ship body (41), the ocean communication and weather monitoring part (42) is arranged at the middle position of the upper surface, and the ship identification plate (432) is arranged at the side of the ocean communication and weather monitoring part (42); the heading stabilization part (44) comprises a tail fin part (441) and a buoy part (442), the tail fin part (441) is arranged at the lower surface of the tail of the ship body (41), and the buoy part (442) is arranged at the tail of the ship body.

4. A wave propelled unmanned ship according to claim 3, characterized in that: The umbilical cable part (5) comprises an umbilical cable (51) and umbilical connecting parts (52) at both ends of the umbilical cable (51), the umbilical connecting part (52) connected with the unmanned ship body (4) comprises horizontal turning parts (521), pitching turning parts (522) and heeling turning parts (523) connected in sequence, the horizontal turning parts (521) are connected with the unmanned ship body (4), the heeling turning parts (523) are connected with the umbilical cable (51), the horizontal turning parts (521) can rotate in a horizontal plane, the pitching turning parts (522) can rotate in a pitching direction, and the heeling turning parts (523) can rotate in a heeling direction; bosses are arranged on the unmanned ship body (4) and the underwater glider with nonlinear rigidity, and are used for fixing the umbilical connecting part (52), and the umbilical connecting part (52) connected with the underwater glider with nonlinear rigidity only comprises the pitching turning parts (522) and the heeling turning parts (523) connected with the pitching turning parts (522).

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