Array type underwater propeller with high maneuverability and low energy consumption

Abstract

The invention relates to an array type underwater propeller with high maneuverability and low energy consumption, a pump jet generating device and a flow divider jointly form a propeller front end, an intelligent fluid director forms a propeller rear end, and the pump jet generating device drives an impeller through a rotating motor to drive surrounding water flow to rotate to generate a main jet flow; an isolation structure is arranged in the flow divider and used for evenly dividing the main jet flow into multiple strands of independent sub jet flows, and all the sub jet flows form propelling power after entering the intelligent flow guider to be guided. The intelligent fluid directors are connected with the flow channels of the flow divider in a one-to-one correspondence mode and used for converting fluid flowing out of the flow divider and out of the jet flow face into effective action jet flow with the adjustable flow speed. The intelligent fluid director comprises a jet flow end regulation and control mechanism and a pressure relief end regulation and control mechanism, and the jet flow end regulation and control mechanism is used for independently regulating the flow speed of effective jet flow ejected from the fluid director; and the pressure relief end regulation and control mechanism is used for maintaining the constant flow velocity at the inlet of the fluid director by releasing part of water flow when the effective jet flow velocity is regulated.

Description

Technical Field

[0001] This invention relates to the field of underwater propulsion equipment technology, specifically an array-type underwater thruster that achieves efficient propulsion by dynamically adjusting the jet velocity, the shape of the guide fairing, and its surface microstructure. Background Technology

[0002] Currently, underwater thrusters mainly consist of array-type underwater thrusters composed of multiple independent thrusters, as well as variable-direction vector thrusters, each of which is independently controlled. Research on array-type underwater thrusters focuses primarily on layout optimization, cooperative control, and power distribution to improve maneuverability, redundancy, and stability. Existing technologies have achieved thrust distribution control across multiple thrusters. However, the more thrusters there are, the higher the cost, energy consumption, and weight, limiting the lightweight and highly maneuverable applications of thruster arrays. Meanwhile, reducing underwater drag can effectively improve propulsion efficiency. Current research on drag reduction in underwater thruster fairings mainly focuses on optimizing the fairing's shape and surface drag-reducing structures to improve propulsion efficiency by reducing turbulence and frictional resistance. However, these are all static, passive designs, lacking real-time sensing and feedback adjustment capabilities. Furthermore, existing fairing adjustment technologies rely on motors or mechanical structures, resulting in problems such as bulky size, poor sealing reliability, high energy consumption, and frequent maintenance.

[0003] In existing related technologies, such as patent document (CN114852304A), the positions of six propellers are adjusted through a lifting mechanism to form different layouts. However, one device requires six independent rotary motors, which is heavy, costly, and inflexible. In contrast, this invention uses nine arrayed jets, which can be flexibly controlled to achieve independent control of any jet and flexible turning and reversing. Furthermore, this patent only requires one propeller, resulting in lower weight, lower cost, and higher flexibility.

[0004] Patent document (CN115743485B) describes an integrated drag-reducing and vibration-damping deep-sea rim propeller. Through a matching design between the guide shell and the rim propeller assembly, combined with a water-lubricated friction pair and a compression spring, drag and vibration reduction are achieved, but it is still a mechanical, passive adjustment method. Patent document (CN115593160A) describes a foldable drag-reducing fairing for a planetary gear-type amphibious robot. It uses a foldable fairing and a linkage mechanism to switch between water and land modes, but it relies on a motor drive, resulting in energy consumption and sealing issues. Patent document (CN120229352A) describes a method that uses a servo motor to adjust the shield scale angle of attack in real time, combined with sensor feedback to adaptively optimize the flow field; it also relies on a motor drive.

[0005] Existing underwater thruster arrays are insufficient to meet the urgent needs of underwater equipment for lightweight design, adaptability, high maneuverability, and low power consumption. Therefore, this invention proposes a novel array-type underwater thruster that fundamentally overcomes the inherent shortcomings of traditional technologies.

[0006] Therefore, it is necessary to propose a single-propeller multi-jet array based on porous deformable single propeller and an intelligent fairing adjustment mechanism based on shape memory alloy (SMA), with a passive adaptive SMA biomimetic scale structure on the surface, to achieve low-power active / passive composite deformation adjustment, fundamentally overcoming the inherent defects of traditional technologies. Summary of the Invention

[0007] The present invention aims to provide a highly maneuverable and low-energy-consumption array-type underwater thruster to solve the following three technical problems:

[0008] (a) To address the following problems caused by the reliance on a large number of independent rotating motors in existing thruster arrays:

[0009] (1) The large number of thrusters leads to high cost, high energy consumption and heavy weight.

[0010] (2) The problem of low propulsion efficiency caused by flow field interference between each propeller in the propeller array.

[0011] (3) The cavitation effect caused by multiple independent rotating motors affects propulsion stability and underwater noise.

[0012] (4) Conventional multi-channel split arrays cannot achieve independent and autonomous control of the flow rate of each split channel in the array.

[0013] (II) Solve the following technical problems caused by the reliance on motor drive or mechanical transmission structure in the existing fairing adjustment technology:

[0014] (1) The large size and space occupation caused by the complex mechanical structure;

[0015] (2) Risk of failure during long-term underwater operation due to insufficient dynamic sealing reliability;

[0016] (3) The inherent high energy consumption characteristics of motor drive systems;

[0017] (4) The mechanical transmission components have insufficient durability in corrosive environments;

[0018] (5) Vibration and noise interference during the adjustment process;

[0019] (6) The style of the fairing shape adjustment is limited and monotonous;

[0020] (7) The fairing lacks deformation recovery capability, and is unable to repair minor impact deformation.

[0021] (III) Solving the technical problem that the existing biomimetic structure of the flow guide cannot dynamically adjust the surface morphology to adapt to changes in flow velocity, resulting in limited noise reduction and drag reduction performance:

[0022] (1) Traditional flow guide biomimetic structures (such as fixed spherical protrusions) cannot dynamically adapt to changes in flow velocity, thus limiting the noise reduction effect.

[0023] (2) Static shark scale design is difficult to optimize noise reduction and drag reduction at the same time, and the flow field control capability is insufficient.

[0024] (3) It is difficult to integrate an efficient and durable active drive structure on a complex curved fairing.

[0025] To solve the above-mentioned technical problems, the technical solution of the present invention is: a highly maneuverable and low-energy-consumption array-type underwater thruster, comprising a pump-jet generator, a flow divider, and an intelligent flow guide. The pump-jet generator and the flow divider together form the front end of the thruster, and the intelligent flow guide forms the rear end of the thruster. The pump-jet generator drives an impeller through a rotating motor to swirl the surrounding water flow, generating a main jet. The flow divider has an internal isolation structure for uniformly dividing the main jet into multiple independent sub-jet streams. Each sub-jet stream enters the intelligent flow guide and, after being guided, forms a thruster. The system provides power input; multiple intelligent flow guides are connected one-to-one with multiple flow channels of the flow divider to convert the fluid flowing out of the flow divider's jet surface into an effective jet with adjustable flow rate; each intelligent flow guide includes: a jet end control mechanism and a pressure relief end control mechanism. The jet end control mechanism is used to independently adjust the flow rate of the effective jet ejected from the flow guide; the pressure relief end control mechanism is used to maintain a constant flow rate at the inlet of the flow guide by releasing part of the water flow when adjusting the effective jet flow rate, so as to avoid interfering with the flow field of other flow guides.

[0026] Furthermore, the jet end control mechanism includes: an annular thermoplastic polyurethane elastomer film and a linear stepper motor. The annular thermoplastic polyurethane elastomer film has multiple deformable holes evenly distributed on it. The output shaft of the linear stepper motor is connected to the outer edge of the thermoplastic polyurethane elastomer film through a linkage mechanism, which is used to change the aperture of the holes by stretching or releasing the thermoplastic polyurethane elastomer film, thereby adjusting the flow rate of the effective jet.

[0027] Furthermore, the pressure relief control mechanism includes: an annular thermoplastic polyurethane elastomer membrane, a linear stepper motor, and an annular pressure relief hole; the annular thermoplastic polyurethane elastomer membrane is disposed on the side of the funnel-shaped structure at the inlet of the flow guide, and has an oblique pressure relief hole on it; the output shaft of the linear stepper motor is connected to an annular retainer, which is used to change the aperture of the pressure relief hole by stretching or releasing the annular thermoplastic polyurethane elastomer membrane; the annular pressure relief hole is disposed on the stainless steel shell of the flow guide, corresponding to the pressure relief hole on the annular thermoplastic polyurethane elastomer membrane, and is used to uniformly spray the discharged water flow in a direction perpendicular to the axis of the thruster at 360°, so that the resultant force of the pressure relief thrust is zero.

[0028] Furthermore, the intelligent flow guide is externally wrapped with an intelligent flow guide cover, which is made of flexible thermoplastic polyurethane material and has multiple sets of shape memory alloy wires embedded inside. By energizing and heating different sets of shape memory alloy wires, they undergo phase change and contraction, thereby actively adjusting the curvature and / or tilt angle of the flow guide cover.

[0029] Furthermore, the multiple sets of shape memory alloy wires include at least three sets, each set of shape memory alloy wires having a different phase transition temperature, thereby enabling stepped deformation output under different temperature and current excitation, and realizing multi-level adjustment of the shroud shape.

[0030] Furthermore, the shape memory alloy wire is wrapped in flexible thermally conductive silicone and externally encapsulated with a flexible thermoplastic polyurethane material with low thermal conductivity to achieve rapid heating response and thermal isolation from the passive biomimetic scale system.

[0031] Furthermore, the intelligent air deflector adopts a composite layered structure, including an outer and inner flexible thermoplastic polyurethane layer, and a fiberglass woven mesh layer sandwiched in the middle. The fiberglass woven mesh layer is used to provide structural rigidity and prevent the flexible thermoplastic polyurethane layer from tearing, while retaining the bending freedom for the shape memory alloy wire to be stretched and deformed. The outer surface of the intelligent air deflector is covered with biomimetic shark scales, which adopt a three-layer gradient composite structure, including: a flexible thermoplastic polyurethane functional surface layer with V-shaped grooves, a high thermal conductivity silicone intermediate layer with embedded passive shape memory alloy wires, and a flat flexible thermoplastic polyurethane elastic base layer. The passive shape memory alloy wires are not connected to an external power source, and their deformation is triggered by the frictional heat generated when the fluid flows through the V-shaped grooves, thereby realizing passive and adaptive adjustment of the scale shape.

[0032] Furthermore, the internal isolation structure of the diverter includes isolation plates and flow-gathering channels. The isolation plates are arranged in a nine-square grid pattern, which can divide the jet of the pump-jet generator into nine uniform parts. The incident flow surface of the flow-gathering channel is square, and the exit flow surface is circular. The square interface and the circular interface are gradually transitioned to reduce water flow resistance and improve fluid energy utilization efficiency. A wire conduit is arranged at the front end of the diverter, which connects the intelligent flow guide and the control box for communication signals. Nine flow velocity sensors are arranged in the nine-square grid formed by the isolation plates to monitor the flow velocity of the current flow channel. The flow velocity sensors adopt SAW flow velocity sensors.

[0033] Furthermore, the thruster also includes a control system that employs a PID negative feedback control strategy:

[0034] PID controller 1 is used to control the motor speed of the pump-jet generator according to the target speed.

[0035] The second PID controller is used to control the pressure relief end regulating mechanism based on the reading of the flow velocity sensor in the distributor, so as to maintain a constant inlet flow velocity in each channel.

[0036] The third PID controller is used to control the jet end adjustment mechanism based on the reading of the flow rate sensor at the outlet of the intelligent flow guide, so as to accurately adjust the final flow rate of each effective jet.

[0037] Furthermore, the pump-jet generator, the diverter, and the intelligent diverter adopt a modular design. The intelligent diverter can be connected and fixed to the diverter via a slot, which facilitates disassembly, maintenance, and upgrades.

[0038] Compared with the prior art, the present invention has the following advantages:

[0039] This invention solves the following problems caused by the reliance on a large number of independent rotating motors in existing thruster arrays:

[0040] (1) The large number of thrusters leads to high cost, high energy consumption, and heavy weight. Since the thrust power source of this invention is only one motor, it needs to rely on a splitter and intelligent guide to achieve differentiated thrust distribution. In contrast, if a traditional motor array is used, nine independent thrust controls would require nine independent motors for the same number of arrays. The power consumption of this invention is significantly lower than that of traditional arrays. Due to the reduction in the number of rotating motors, the weight and cost are significantly reduced.

[0041] (2) The problem of low propulsion efficiency caused by flow field interference between each propeller in the propeller array.

[0042] Traditional array-type propellers generate nine high-speed rotating vortices from nine rotating thrusters. These vortices, being close together, interfere with each other, severely reducing propulsion efficiency. However, this invention uses a splitter to divide the water flow into nine streams. The splitter has a guiding effect, reducing the rotational speed of the water streams. Furthermore, the intelligent flow divider is relatively long, and after passing through the TPU, the fluid rotational speed is significantly reduced, resulting in stable jets. This reduces interference between the jet flow fields and improves propulsion efficiency.

[0043] (3) Solve the problem of cavitation effect caused by multiple independent rotating motors, which in turn affects propulsion stability and underwater noise.

[0044] Traditional array-type thrusters utilize multiple rotating motors to propel blades at high speeds underwater. The interaction between the blades and the water flow creates localized cavitation. As the blades rotate, the local pressure drops below the saturated vapor pressure of water, causing the liquid to vaporize and form bubbles (cavitation). These bubbles collapse instantaneously when they reach high-pressure areas, generating shock waves and microjet streams. These bubbles occupy the flow channels, altering the flow field distribution on the blade surface and reducing effective thrust. Repeated shock waves from collapsing bubbles (up to 1 GPa) cause pitting and peeling on the blade surface. The periodic generation and collapse of cavitation bubbles leads to thrust fluctuations, affecting the stability of the control system. This patent, however, uses an independent rotating motor combined with flow-dividing control, requiring only one rotating motor compared to multiple motors. This significantly reduces the cavitation effect of array-type thrusters underwater. Furthermore, the jet from the intelligent guide is a stable jet after guidance, exhibiting no cavitation effect at the jet's injection interface. This improves propulsion stability and significantly reduces underwater noise, facilitating underwater concealment.

[0045] (4) A novel underwater independent jet array adjustment method is provided.

[0046] By employing a flow divider and intelligent flow guide, and by setting flexible pressure relief TPUs and jet TPUs (i.e., changing the orifice size of the pressure relief and jet channels), the ratio of jet to pressure relief flow is adjusted, enabling independent control of individual jets in the jet array. This solves the problem in conventional arrays where adjusting the flow rate of only one jet end affects the velocities of the other jet ends, thus achieving decoupling between multiple jet arrays. All nine jet ends share a single motor and propulsion source (pumped water flow), and each of the nine jet ends can be controlled independently without affecting the others.

[0047] This invention solves the following technical problems caused by existing fairing adjustment technologies that rely on motor drive or mechanical transmission structures:

[0048] (1) Space optimization effect

[0049] By directly embedding 60 SMA filaments (12 sets x 5 strands) with a diameter of only 0.5mm into the TPU fairing substrate, the traditional transmission structure such as motors and gears is completely eliminated. Based on the volume ratio of SMA filaments to TPU material, this design can reduce the volume of the drive system by more than 90%, and the overall thickness of the fairing can be controlled within 10mm, while traditional electric adjustment mechanisms usually require more than 30mm of installation space.

[0050] (2) Sealing performance advantages

[0051] Because the SMA filaments are completely encapsulated by the TPU material, a continuous waterproof barrier layer is formed. The TPU has a water absorption rate of less than 0.5%, and the SMA filaments operate in a sealed environment, completely preventing external water penetration and ensuring long-term operational stability. Compared to traditional mechanical transmissions that require dynamic seals, this method fundamentally solves the problem of sealing reliability.

[0052] (3) Energy consumption reduction characteristics

[0053] Driving a single SMA filament to its phase transition temperature requires only 1.5-3A of current, and power is consumed only during deformation. Under the same deformation requirements, the power consumption of this system can be reduced by more than 80% compared to traditional motor systems, and it consumes almost no power during steady-state operation.

[0054] (4) Improved environmental durability

[0055] From a materials science perspective, NiTi alloy itself possesses excellent corrosion resistance (annual corrosion rate <0.001 mm / a), and the TPU coating further isolates it from corrosive media. Compared to traditional stainless steel transmission components, this design can reduce the risk of corrosion failure by an order of magnitude.

[0056] (5) Vibration and noise control

[0057] Because it uses a solid-state drive principle, the system theoretically does not generate mechanical noise such as gear meshing, and can eliminate mechanical vibration noise in the 200-5000Hz frequency band, making it particularly suitable for acoustically sensitive application scenarios.

[0058] (6) Morphological adjustment ability

[0059] By using three sets of SMA filaments with different phase transition temperatures working together, the radius of curvature can be continuously adjusted (5-8mm), and the tilt angle can be dynamically changed (30°-50°).

[0060] (7) Self-healing characteristics

[0061] Based on the shape memory effect of SMA, the fairing can completely recover its original shape after being deformed by less than 5% by simple heating. Compared with traditional composite materials, this property can significantly improve the equipment's damage resistance and ease of maintenance.

[0062] This technology also has the following advantages in addressing the specific needs of intelligent fairings:

[0063] Dynamic flow field adaptation: Gradient phase change temperature design enables the system to automatically adapt to changes in flow velocity.

[0064] Acoustic and vibration performance optimization: Active deformation can change the flow field characteristics and reduce eddy noise.

[0065] Surface integration capability: Flexible SMA wires can adapt to complex curved surface arrangements.

[0066] This invention solves the technical problem that existing biomimetic structures for flow deflectors cannot dynamically adjust their surface morphology to adapt to changes in flow velocity, resulting in limited noise reduction and drag reduction performance.

[0067] (1) Adaptive capability of dynamic flow field

[0068] The passive adjustment system uses precisely designed passive SMA filaments (phase change temperature 45℃) to sense flow velocity. When the flow velocity exceeds 12m / s, the scale morphology can be adjusted within 8 seconds (curvature radius 8mm→5mm, tilt angle 50°→30°) solely through fluid frictional heat. Compared to traditional fixed biomimetic structures, the boundary layer transition point is delayed by 15-20%, and the noise reduction effect is improved by more than 40%.

[0069] (2) Multiphysics Collaborative Optimization

[0070] The three-layer gradient composite structure creatively integrates: the hydrodynamic properties of the TPU functional layer (V-groove), the intermediate layer containing 30wt% boron nitride filler achieving 2.5W / mK directional thermal conductivity, and the elastic TPU base layer providing 0.8N / mm². 2 The recovery force and laser micro-hole interlocking design increase the interlayer shear strength by 300% while ensuring unobstructed heat flow channels.

[0071] (3) Complex Surface Integration Scheme

[0072] The 0.2mm diameter micro SMA filaments achieve unidirectional shrinkage through symmetrical distribution. The flexible silicone interlayer allows for localized strain up to 15%, perfectly adapting to the deformation of hyperbolic surfaces. The passive adjustment system requires no wiring and achieves mechanical-thermal coupling through laser-drilled micropores (0.1mm diameter).

[0073] (4) Breakthrough in energy efficiency and reliability

[0074] The passive system achieves zero-energy regulation, saving 60% more energy compared to a purely active system. The three-layer structure design gives the scales a peel resistance of 50 N / cm, far exceeding traditional adhesive bonding solutions.

[0075] (5) Intelligent damage recovery

[0076] The low phase transition temperature of 45℃ ensures spontaneous repair of minor damage when the ambient temperature fluctuates. The synergistic effect of the TPU substrate and SMA enables a reset accuracy of ±0.2mm. The composite structure can completely recover its initial shape after 5% compression deformation. Attached Figure Description

[0077] Figure 1 An oblique view of the intelligent flow guide structure;

[0078] Figure 2 A schematic diagram showing the thrust cancellation of the pressure relief flow (66) at the pressure relief end of the intelligent flow guide;

[0079] Figure 3 The diagram shows a plan view of the intelligent flow guide structure, where (a) is the front view and (b) is the sectional view of the FF.

[0080] Figure 4 A magnified view of a portion of the internal structure of the intelligent flow guide;

[0081] Figure 5 A schematic diagram of the annular disk (48) and its connection relationship in the intelligent flow guide;

[0082] Figure 6 The images show the top view and sectional view of the intelligent flow guide structure, where (a) is the sectional view of AA and (b) is the top view.

[0083] Figure 7 A cross-sectional view of the intelligent flow guide, showing the stainless steel shell serving as the frame and structure of the intelligent flow guide.

[0084] Figure 8 The working principle diagram of the jet end TPU (46) in the intelligent flow guide under different stretching states is shown, where (a) is the fully closed state, (b) is the 50% stretching state, and (c) is the fully open state.

[0085] Figure 9 This is a schematic diagram showing the flow direction conversion of the pressure relief flow in the intelligent flow guide;

[0086] Figure 10 A schematic diagram showing the deformation of the flow guide before and after heating the SMA filament;

[0087] Figure 11 A schematic diagram showing the state of the TPU (27) at the pressure relief end in the intelligent flow guide at different stretching positions (36, 110, 37);

[0088] Figure 12 The diagram shows the external and internal structure of the intelligent flow guide, where (a) is the external structure, (b) is the DD cross-sectional view, and (c) is the HH cross-sectional view.

[0089] Figure 13 This is a schematic diagram of the layered structure and SMA filament distribution of the intelligent air deflector;

[0090] Figure 14 A schematic diagram of the external biomimetic shark SMA scales of the intelligent air deflector;

[0091] Figure 15 A schematic diagram of installing a flow velocity sensor (87) in the outflow channel of an intelligent flow guide;

[0092] Figure 16This is a schematic diagram of the pump-jet generator, where (a) is the front view, (b) is the AA sectional view, and (c) is the CC sectional view.

[0093] Figure 17 This is a schematic diagram of the external and internal structure of the pump-jet generator, where (a) is a right view and (b) is a CC sectional view;

[0094] Figure 18 This is an exploded perspective view of the array-type underwater thruster structure of the present invention;

[0095] Figure 19 This is a three-dimensional schematic diagram of the array-type underwater thruster structure of the present invention;

[0096] Figure 20 This is a schematic plan view of the overall structure of the array-type underwater thruster of the present invention, wherein (a) is the front view and (b) is the FF sectional view;

[0097] Figure 21 This is a left view of the overall structure of the array-type underwater thruster of the present invention;

[0098] Figure 22 The schematic diagram of the PID control system of the present invention is shown, wherein (a) is motor speed control, (b) is flow velocity control at the pressure relief end, and (c) is flow velocity control at the jet end.

[0099] Figure 23 This is a block diagram of the hardware system connection of the present invention. Detailed Implementation

[0100] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0101] like Figures 1 to 23 As shown, this invention discloses a highly maneuverable and low-energy-consumption array-type underwater thruster, comprising three parts: a pump-jet generator, a flow divider, and a smart flow guide. The pump-jet generator and the flow divider together form the thruster's front end, while the smart flow guide forms the thruster's rear end. The smart flow guide can be inserted and fixed through a slot in the flow divider. The thruster's front and rear ends are separated, adopting a modular design for easy assembly, maintenance, and upgrades. The fluid diverted by the flow divider enters the smart flow guide, where it is guided to generate propulsion power.

[0102] Composition and working principle of the pump-jet generator: A motor 1 drives a rotating shaft 3 to rotate. An impeller 2 is mounted on the shaft 3. The impeller 2 drives the surrounding water flow to rotate, forming a stable forward-rotating water flow within the casing 4. The blades of the impeller 2 circle the hub multiple times (continuous spiral impeller), which extends the water flow acceleration path, allowing the fluid to pass through the propeller more smoothly and providing a more stable flow field for the subsequent diverter and intelligent guide. The motor 1 is fixed by a fixed bracket 5, with four fixed brackets symmetrically distributed at 90° in plane. The motor's control and feedback leads are led from the wiring box 9 to the electrical control box 10. The wiring box contains the wires 19 required to control the motor. The control box 10 consists of a controller 7 and connectors (12-17). The controller is responsible for receiving sensor signals, calculating decisions, and outputting control signals. The connector includes 2 Ethernet ports (15), 2 RS485 ports (12), 1 RS422 port (13), 1 RS232 port (14), 2 CAN ports (15), 1 debugging interface (17), and 1 power interface (16). The RS485 / 232 / 422 interfaces use standard DB9 interfaces, and the Ethernet / CAN interfaces use standard high-speed aviation connector interfaces to ensure the speed and stability of signal transmission. The debugging interface uses ordinary plug-in terminal form, and the power interface uses aviation connector interfaces to ensure the stability of the interface connection. The control box 10 and the flow guide shell 4 are integrated into one unit, and the control box can be opened through the top cover 11. The propeller inlet cover 6 has evenly arranged inlet channels, which together with the flow divider form a fluid passage. The inlet cover 6 is fixed to the flow guide shell 4 by fastening bolts 18, which facilitates the installation and disassembly of the motor 1.

[0103] The function of the diverter is to divide a single flowing fluid into multiple equal streams, ensuring that the isolated streams maintain similar velocities and flow rates as much as possible. The isolation plates 19 are arranged in a nine-square grid, dividing the jet from the pump-generating device into nine uniform parts. The incident flow surface 21 of the converging duct 20 is square, and the exit flow surface 22 is circular, with a gradual transition between the square and circular interfaces to reduce flow resistance and improve fluid energy utilization efficiency. A wire conduit 23 is arranged at the front end of the diverter, connecting the intelligent diverter to the control box 10 for communication signals. Within the nine-square grid formed by the isolation plates 19, nine flow velocity sensors 24 are arranged to monitor the current flow velocity in the channel; these flow velocity sensors are SAW flow velocity sensors.

[0104] The function of the intelligent flow guide is to convert the fluid flowing out of the outlet flow surface 22 of the distributor into an effective jet 92-100 with adjustable flow rate (flow rate sensor 87 measures the flow rate). Pressure relief at the injection end of the intelligent flow guide ensures that it does not affect the flow rate of other channels within the distributor. The stainless steel shell 25 serves as the skeleton of the intelligent flow guide, controlling the injection front end to be funnel-shaped, with uniformly spaced grooves on the side of the funnel. The pressure relief hole 26 penetrates the stainless steel shell 25, forming an internal and external passage, and the direction of the grooves is perpendicular to the central axis 32 of the flow guide. The annular stretchable thermoplastic polyurethane elastomer (TPU) 27 at the pressure relief end is uniformly cut with pressure relief holes 38 at 45° (relative to the central axis 32) along a tangential line, with the grooves penetrating the TPU to form through holes. The inlet end of the annular TPU is fixed by an annular groove 28, which has regular serrations that embed and compress the TPU. Fastening screws 30 fix the groove 28, the stainless steel shell 25, and the annular TPU 27 together, further restricting the movement of the outer end of the TPU. The outer ring retainer 29 is fixed to the stainless steel shell 25 by fastening bolts 31, and also serves to press and restrict the movement of the groove 28. A parallel gap band is left between the annular TPU 27 and the stainless steel shell 25. After liquid is ejected from the annular TPU 27, it can converge into the gap band and be ejected from the pressure relief hole 26 along a direction perpendicular to the central axis 32 of the guide. The pressure relief direction is a 360° scattering pattern, and the pressure relief direction is perpendicular to the central axis 32. The thrust generated by pressure relief in each direction cancels out, and the resultant pressure relief thrust is 0. Figure 2 The outlet end of the ring-shaped TPU is fixed by a ring retainer 33. The ring retainer 33 is movable and fixed to the shafts 35 of two symmetrical linear stepper motors 34. The shafts of the linear stepper motors can reciprocate linearly along their axes (motors 34 are mounted on the inner wall of the guide), and the ring retainer 33 reciprocates linearly by controlling the forward or backward movement of the control 35. The range of reciprocating motion is between the dashed lines 36 and 37. Figure 3 As shown in (b) and 11(b), the annular TPU 27 is stretched to half its stroke. At this time, the annular retainer 33 is located between the stretchable strokes 36 and 37, and the pressure relief hole 38 is stretched into a quadrilateral opening. When the annular retainer 33 is in position 36 ( Figure 11 c) At this time, the TPU is not stretched, the pressure relief hole 38 is closed, the pressure relief hole 26 does not release pressure externally, and the incoming flow 39 of the smart flow guide will not pass through the pressure relief hole 26. When the annular retainer 33 is in position 37 ( Figure 11a) At this point, the TPU has the maximum stretch ratio, the pressure relief hole 38 is in its most open state, the pressure relief hole 26 releases pressure externally, and the incoming flow 39 will release a large amount of pressure through the pressure relief hole 26. The annular slot 40 is fixed on the limiting platform 41 and clamped by the annular limiter 42, which is secured by the fixing pin 43. The annular slot 40 is evenly connected to four connecting rods 44 of equal length and thickness. The ends of the connecting rods are connected to a hemispherical ring 45. The outer surface of the hemispherical ring 45 is covered with a circular stretchable TPU 46. The outer ring end of the TPU is connected to an annular metal hook 47. The protrusion of the annular hook 47 is firmly locked in the recess of the annular disk 48. The annular ring 48 is connected to the shaft 50 of two opposing linear stepper motors 49. The guide sleeve 53 on the annular disk 48 can slide along the connecting rod 44. The linear stepper motor 49 drives the annular disk 48 on the shaft 50 to reciprocate linearly, which in turn drives the annular hook 47 to move. The annular hook 47 drives the outer end of the TPU to move, and the TPU stretches against the hemispherical surface of the hemispherical ring 45. The TPU is always flat on the inner ring of the hemispherical ring 45, and curved on the outer ring. Numerous circular holes 54 are evenly distributed on the TPU. The movement range of the annular disk 48 is between the dotted lines 51 and 52. When the annular disk 48 is at the position of the dotted line 52, the TPU is not stretched, the circular holes 54 are closed, and the incident flow 39 cannot pass through the TPU. When the annular disk 48 is at the position of the dotted line 51, the TPU is stretched to the maximum extent, the diameter of the circular holes 54 is the largest, and the incident flow 39 can pass through the inner ring plane of the hemispherical ring 45 with almost no resistance. The greater the elongation of TPU, the larger the pore diameter, and the easier it is for the incident flow 39 to pass through the TPU surface.

[0105] Figure 8 (a) shows the unstretched TPU film, at which point the stepper motor shaft 50 has reached its maximum extension length. The annular ring 48 at the end of the shaft 50 is in contact with the hemispherical ring 45. Due to the restriction of the hemispherical ring 45, the shaft 50 cannot extend further. At this time, the holes 54 on the TPU surface are closed, preventing water from flowing from left to right, and the water jet speed is 0.

[0106] Figure 8 (b) This diagram shows the TPU film stretching to 50%. The stepper motor shaft 50 retracts, causing the annular ring 48 to retract to the middle position between positions 51 and 52. The guide sleeve 53 slides along the connecting rod 44 and restricts the movement path of 48 to a straight line, allowing the annular disc 48 to move perpendicular to the central axis 32. At this time, due to the stretching of the TPU, the originally closed holes 54 open. The TPU forms a perforated sieve structure within the circular area surrounded by the hemispherical ring 45, allowing water to flow from left to right through the holes 54. Since the diameter of the holes 54 is only half at this time, the water jet speed is limited.

[0107] Figure 8 (c) shows the state where the TPU film stretches to 100%. The stepper motor shaft 50 retracts further, driving the annular ring 48 to retract to position 51. As the TPU is further stretched, the hole 54 opens further, allowing water to flow out more easily. Since the hole 54 is fully open at this time, the water jet speed reaches its maximum value.

[0108] The greater the stretch of the TPU, the easier it is for water to pass through the hole 54 and the TPU 46, resulting in a higher water jet speed from left to right. Conversely, the smaller the stretch of the TPU, the more difficult it is for water to pass through the hole 54 and the lower the water jet speed from left to right. The water jet speed depends on the stretch of the TPU, which is equivalent to the stepping amount of the stepper motor shaft 50, and thus the position of the annular ring 48 at the end of the shaft 50. The water jet speed can be controlled by adjusting the position of the stepper motor shaft.

[0109] The pressure relief principle of the intelligent flow diverter is explained using the flow divider as an example. A flow divider has nine slots: 55-63. Each slot is used to insert an intelligent flow diverter. The forward-moving water flow generated by impeller 2 is divided into nine equal parts by the nine slots, each flowing into an intelligent flow diverter through its own channel. For example, when the orifice 54 inside the intelligent flow diverter in slot 59 narrows, the resistance of the TPU46 to the water increases, causing the incoming flow 39 to become blocked inside the funnel-shaped inlet 64 of the flow diverter. The water that should have entered flow diverter 59 will instead flow out through the remaining eight slots due to the blockage by the TPU46, resulting in an increased flow velocity in the remaining channels. Without a pressure relief device, the change in the flow velocity through the TPU46 of one intelligent flow diverter will affect the internal flow velocity of the remaining eight diverters. If a pressure relief device is installed at the inlet of the flow guide, the pressure relief amount can be controlled to ensure that the velocity of the single flow guide inlet jet 39 is not affected regardless of the diameter of the hole 54, and thus will not interfere with the flow velocity of the intelligent flow guides in other slots.

[0110] The working principle of the pressure reducing device is as follows: before the TPU stretch ratio changes and with the impeller 2 rotating at a constant speed, the radial flow velocity within the funnel-shaped inlet 64 is constant, and the value of the flow velocity sensor 24 remains unchanged. When the diameter of the jet orifice 54 decreases, the flow velocity within the funnel-shaped inlet 64 decreases because the water flow has more difficulty passing through the TPU 46, resulting in a decrease in the value of the flow velocity sensor 24. A PID negative feedback control mechanism is introduced: when the value of the flow velocity sensor 24 decreases, the stepper motor shaft 35 is immediately driven to retract to the right, driving the annular retainer 33 to stretch to the right 27, thus increasing the diameter of the pressure relief orifice 38. The incoming flow 39 will then flow outward through the pressure relief orifice 38, forming the pressure relief flow 65. Figure 9To increase the contact area between the incident flow 39 and the TPU 27, the incoming surface of the TPU 27 is designed in a funnel shape. Simultaneously, the opening direction of the pressure relief hole 38 on the TPU 27 forms a 45° angle with the central axis 32, allowing the jet 65 to more easily impact and pass through the pressure relief hole 26. The jet 65 will form a pressure relief flow 66 perpendicular to the central axis 32 through the pressure relief hole 26. The pressure relief hole 38 on the TPU 27 is deformable, while the pressure relief hole 26 on the stainless steel casing 25 is non-deformable.

[0111] Figure 11 Three typical positions are illustrated, from left to right: the maximum TPU stretch position 37 at the pressure relief end, the medium TPU stretch position 110, and the no-stretch TPU position 36. The stretching stroke is within the range shown in positions 36 and 37. As the annular retainer 33 moves from position 36 to position 37, the pressure relief orifice 38 gradually opens, increasing the flow rate of the pressure relief flow 66 in the pressure relief orifice 26. When the annular retainer 33 is in position 37, the orifice diameter of the pressure relief orifice 38 is at its maximum, resulting in the most significant pressure relief effect. When the annular retainer 33 is in position 36, the pressure relief orifice 38 is completely closed, and the incident flow 39 will pass entirely through the circular orifice 54.

[0112] like Figure 9 As shown, the pressure relief flow 66 will be uniformly sprayed in all directions at 360 degrees along a direction perpendicular to the central axis 32. Since the pressure relief hole 26 of the stainless steel outer shell 25 has an annular hollow structure, ribs 67 are needed to improve the stability of the pressure relief structure. One rib is set every 90 degrees around the central axis 32, for a total of four ribs. In the four pressure relief zones formed between the four ribs, the pressure relief flow 66 will generate four equal-sized pressure relief thrusts F0, F1, F2, and F3 outwards. Furthermore, F1 and F3, and F2 and F0, are equal in magnitude and opposite in direction within the same plane, respectively. F1 and F3, and F2 and F0, respectively cancel each other out, resulting in a net force of zero on the propulsion system from the pressure relief flow 66, thus not interfering with the vehicle's motion.

[0113] The control principle of thruster adjustment:

[0114] Figure 22(a) The given (target) speed of impeller 2 is compared with the current speed actually measured by the motor encoder. The deviation between the two is calculated by the PID control function in section 7 to obtain the PID output value, which is then converted from digital to analog and output as a PWM drive signal (adjusting the PWM duty cycle). The speed of motor 1 changes, and the speed measured by the encoder is compared with the given speed of impeller 2 to achieve real-time PID negative feedback of the motor speed until the current real-time speed of impeller 2 equals the given speed. The change in motor speed will cause the values ​​of the nine flow rate sensors 24 in the splitter channel to change. When the annular ring 48 is in position 51 and the annular retainer 33 is in position 36, the flow rate measured by the flow rate sensor 24 at this time is called the calibrated flow rate, that is, the pressure relief hole 38 is closed and the jet hole 54 is fully open (maximum opening). The flow rate at this time will be used as the maximum (calibrated) flow rate of the current splitter channel. When specifying the jet velocity of the intelligent flow guide, and assuming the impeller 2's rotational speed remains constant, adjusting the diameter of the jet orifice 54 requires adjusting the diameter of the pressure relief orifice 38 to ensure that the readings of the corresponding flow rate sensor 24 within the flow channel are equal before and after adjustment. This prevents any impact on other flow channels of the flow guide. When the impeller 2's rotational speed changes, the calibrated flow rate of the corresponding flow rate sensor 24 also changes. Each rotational speed value of the impeller 2 corresponds to a calibrated flow rate (constant value) of the flow rate sensor 24. The correspondence between the impeller 2's rotational speed and the calibrated flow rate of the flow rate sensor 24 within the motor speed adjustment range is obtained, serving as the standard for determining the calibrated flow rate of the flow rate sensor 24.

[0115] Figure 22 (b) When the impeller 2 operates at a specified speed, the current calibrated flow rate of the flow rate sensor 24 is obtained based on the correspondence between the impeller 2's speed and the calibrated flow rate of the flow rate sensor 24. The difference between the calibrated flow rate of the flow rate sensor 24 and the current real-time measured flow rate of the flow rate sensor 24 is used to obtain a PID output value through the PID2 function. The controller 7 reads the PID output value and outputs a drive signal for the motor 34 through digital-to-analog conversion, causing a change in the extension and retraction of the stepper motor shaft 35. This results in a change in the orifice diameter of the pressure relief orifice 38, and the change in the pressure relief flow rate 65 / 66 will cause a change in the reading of 24 in the diversion channel. This is then compared with the calibrated flow rate of the flow rate sensor 24 to form a PID negative feedback adjustment at the pressure relief end. This continues until the current reading of the flow rate sensor 24 equals the calibrated flow rate of the flow rate sensor 24.

[0116] Figure 22 (c) When a jet velocity of 92-100 is given to the intelligent flow guide, the given jet velocity is compared with the velocity sensor 87 in the corresponding flow channel (see...). Figure 15The difference in real-time flow velocity measured is used to obtain the PID output value through the PID3 function. The controller 7 reads the PID output value and outputs the drive signal of the motor 49 through digital-to-analog conversion. The extension and retraction of the shaft 50 changes, which causes the aperture of the hole 54 to change. The jet velocity 92-100 changes. The current jet velocity measured by the flow velocity sensor 87 is compared with the given jet velocity to form a negative feedback adjustment of the jet velocity until the current jet velocity of the flow velocity sensor 87 is equal to the given jet velocity.

[0117] The calibrated flow rate of flow velocity sensor 24 depends on the given rotational speed of impeller 2, and the calibrated flow rate of flow velocity sensor 24 determines the maximum value of the given jet velocity (calibrated flow rate of flow velocity sensor 87). The calibrated flow rates of flow velocity sensor 24 and flow velocity sensor 87 are both the maximum flow rates at the given rotational speed of impeller 2 (annular ring 48 is located at position 51, and annular retainer 33 is located at position 36). The above control strategies are all implemented by the control box.

[0118] Figure 23 The diagram shows the hardware connection. A DC uninterruptible power supply (UPS) powers the controller. The controller connects to a multi-channel digital signal acquisition module via an RS485 interface. This module acquires digital signals from flow rate sensors, including flow rate sensor 24 and flow rate sensor 87. The controller also connects to a multi-channel analog signal acquisition module via an RS485 interface. This module acquires analog signals from NTC temperature sensors, including temperature sensor 86. The multi-channel digital / analog signal acquisition modules share a single RS485 signal line as slaves. The controller acts as the master, employing a master-slave communication mode. Each slave is assigned a unique address to distinguish the data target sent by the master. After being isolated by a signal isolation module (magnetic coupler isolator to achieve common mode rejection of >100kV / μs), the controller is connected to drive amplifier modules 1 / 2 / 3 to control the stepper motor, rotary motor and SMA respectively. The three power modules have different specifications: module 1 (106) (voltage range: DC 8-36V, current range: 0.5-2.5A / phase (256 microstep adjustable)), module 2 (107) (voltage range: DC 6-48V (supports 12V / 24V / 36V multi-level switching), current range: 0-10A (transient 15A / 1ms)), and module 3 (85) (DC 0-24V (continuously adjustable), current range: 0-3A (resolution ≤10mA)).

[0119] With the increasing demands for efficient propulsion and low noise performance in underwater vehicles, traditional rigid fairings struggle to adapt to complex flow field changes, necessitating a lightweight, adaptive, and intelligent structure. Shape memory alloys (SMAs), with their hyperelasticity, high power density, and temperature-driven spontaneous deformation properties, offer an innovative solution for dynamic flow field control of fairings. By utilizing water temperature changes or external excitation to trigger the phase transition of the SMA, real-time adjustment of the fairing geometry can be achieved, thereby optimizing fluid separation, reducing turbulent drag, and adapting to different speed conditions. This paper proposes an intelligent fairing design based on SMAs, combining elastic material encapsulation and thermal conductivity enhancement technology to address the propulsion response problem in underwater environments, providing key technical support for next-generation adaptive underwater propulsion systems.

[0120] To optimize fluid flow (such as air or water) to improve efficiency, reduce resistance, or enhance system performance, the liquid flowing through 54 is guided by a flow deflector 68. The flow deflector is internally composed of 12 groups of SMA (69, 73-83) filaments, each group consisting of 5 fine SMA filaments. To achieve a balance between efficient temperature response and environmental protection, a composite encapsulation structure of "thermally conductive inner layer + thermally insulating outer layer" is used. The 5 SMA filaments are evenly wrapped in thermally conductive silicone, which rapidly transfers the temperature of the SMA filaments, allowing each group of 5 fine SMA filaments to heat up quickly. The outer layer uses TPU material with low thermal conductivity to increase the heating rate, enabling the SMA filaments to deform more quickly. TPU material has high stretchability. Typical elongation at break: TPU's elongation at break is typically between 300% and 800%, far exceeding that of ordinary plastics (such as ABS, only 5% to 50%) or rubber (such as natural rubber, approximately 500% to 700%). Elastic recovery: After stretching, it can basically return to its original shape, exhibiting excellent resilience (rebound rate can reach over 90%), making it suitable for dynamic repeated stretching scenarios. Using TPU as the structural material for the fairing 68, it possesses high strength and elasticity, excellent hydrolysis resistance (water absorption rate <1%), excellent tear resistance (>60kN / m), and salt spray corrosion resistance. Its wide temperature range of -40℃ to 120℃ perfectly matches the requirements of underwater environments. When combined with SMA drive, TPU's 3D printing compatibility enables integrated molding of complex ducts, and its recoverable deformation rate of over 200% ensures synergy with SMA deformation, while its adjustable thermal conductivity of 0.1-5W / m·K optimizes the SMA's heat transfer efficiency. This material combination achieves both structural lightweighting (density 1.2g / cm³) and structural efficiency. 3 Its dynamic sealing performance and drive response speed make it an ideal choice for the next generation of intelligent flow guides.

[0121] Figure 13As shown, the flow deflector 68 adopts a composite layered design. The first and fifth layers are hydrolysis-resistant TPU 70, the second and fourth layers are fiberglass woven mesh 71, and the third layer is high-elasticity TPU 72. The fiberglass woven mesh bypasses the SMA filaments covered and wrapped by silicone 105. The fiberglass woven mesh of the second and fourth layers is responsible for transmitting the bending force of the SMA filaments. The rigid warp-knitted fiber mesh can increase the compressive strength by 300%, and still retains 15° bending freedom in the warp and weft directions for free bending. This ensures that the flow deflector 68 remains rigid underwater and will not cause wrinkles or deformation of TPU 70 and TPU 72 due to the impact of water flow, maintaining the flat and rounded appearance of the flow deflector 68 (conventional flow deflectors are rigid, such as stainless steel; the flow deflector of this invention is a variable soft elastic material TPU, so a rigid fiberglass woven mesh 71 is needed to maintain the appearance of the flow deflector, while also providing a certain degree of bending freedom for the SMA filaments to bend). The TPU molding method is 3D printing, which directly prints it onto the glass fiber mesh and SMA assembly.

[0122] The SMA filaments are uniformly distributed within a 360° range inside the TPU flow guide. SMA filaments 83, 77, 80, and 74 form one control group; SMA filaments 82, 76, 79, and 73 form another; and SMA filaments 81, 69, 75, and 78 form yet another. Each control group has different SMA material properties and characteristics, resulting in different deformation amounts under external excitation, allowing for grouped control of deformation.

[0123] Figure 13 As shown, each SMA filament group consists of five SMA filaments with a relatively thin diameter (typically 0.5 mm). The parallel connection of multiple thin SMA filaments reduces the current required per filament, improves heat dissipation efficiency, and thus drives phase change deformation more efficiently, while enhancing dynamic response performance. A flexible, thermally conductive silicone 105 is wrapped around the five SMA filaments, ensuring uniform heating and faster heat transfer, thereby improving the response speed of the SMA filaments.

[0124] This invention relates to a multi-level deformation control system for a shape memory alloy (SMA) driven fairing based on multi-channel independent control. The system is characterized by employing a graded driving architecture to achieve progressive deformation control of the fairing. The system comprises three independently controlled SMA driving units, each consisting of SMA filaments of a specific alloy composition, a driving amplification module, and a real-time temperature monitoring module. The three sets of SMA filaments undergo differentiated heat treatment processes, resulting in different phase transition temperature ranges and recovery strain characteristics. When electrically heated, the three sets of SMA filaments can produce a stepped deformation output.

[0125] Each channel is equipped with an independent constant current drive amplifier module 85, connected to the main controller 7, for receiving commands and outputting a high-precision adjustable 0-3A drive current (corresponding to SMA phase transition temperatures of 20℃-120℃). Its operating voltage adapts to changes in load resistance (DC 0-24V) and has a dynamic response speed of less than 10ms (10%-90% of rated current step response). The output of the constant current drive amplifier module 85 of each channel is connected in series with an independent overcurrent protection module 84. This module monitors the SMA current in real time through high-side current detection (accuracy ±1%). When it exceeds 3.3A (110% Imax), the hardware comparator triggers the MOSFET to turn off within 500ns and outputs a fault signal to the controller 7. The protection state needs to be manually reset to ensure that the system does not automatically restart before the fault is cleared. The control system adopts an adaptive PID algorithm combined with high-frequency PWM regulation, and a distributed temperature measurement network constructed with surface-mount temperature sensors (sampling rate 1kHz) to achieve a steady-state temperature control accuracy of ±1℃.

[0126] The control software adopts an event-driven architecture, which can automatically coordinate the working timing and power distribution of the three drive units according to the preset deformation program, so as to achieve a smooth transition of the fairing from the initial state to the target shape. Through the coordinated drive of multiple sets of SMA wires, precise control of the complex deformation of the fairing is achieved.

[0127] Figure 10 This diagram illustrates the deformation of the SMA (Surface Mounted Aluminum) shroud controlled by the SMA. The top image shows the SMA wire in its original state with zero deformation, while the bottom image shows the deformation of the shroud after heating the SMA wire. The bending of the SMA wire reduces the opening of the shroud. The amplification module 85 is located within the electrical control box 10. Three independent drive amplification modules output current to the five thin SMA wire groups via three independent overcurrent protection modules 84. An NTC thermistor 86 is embedded inside the TPU, and the current SMA wire temperature is obtained in real time by measuring the thermistor's resistance. Each SMA wire group is equipped with three NTC thermistors, evenly distributed along the length of the SMA wire.

[0128] This relates to a biomimetic adaptive fluid control device based on passive shape memory alloy actuation, wherein biomimetic shark SMA scales 120 are arranged on the outside of the flow guide shroud (see...). Figure 14The SMA flakes 120 consist of four parts: a TPU surface layer 89 with arrayed V-shaped grooves, a flexible, thermally conductive silicone rubber layer 90, and a bottom layer of TPU with a smooth outer surface 91. The silicone rubber 90 encases three parallel, fine SMA filaments 88. These SMA filaments are passive and not connected to any power source. When water flows through the V-shaped grooves, it generates frictional heat with the interior of the grooves. This stimulates the SMA filaments to change shape, achieving adaptive flow field regulation. Its core lies in achieving adaptive flow field control without external energy through a special layered structure design. When fluid flows over the surface 89, the frictional heat generated by the interaction between the fluid and the surface V-shaped groove structure is transferred through the thermally conductive layer 90 to the shape memory alloy element 88, inducing deformation and thus changing the geometry of the flakes 120. This dynamic deformation further affects the flow field distribution, forming a closed-loop adaptive regulation mechanism. The entire operation is driven by fluid-structure thermodynamic coupling, requiring no external power supply or control system, thus achieving true passive intelligent regulation. Through coordinated optimization of material selection and structural design, the device ensures reliable response characteristics and durability under complex flow field conditions.

[0129] Example 1: Intelligent fairing system based on SMA drive

[0130] This invention provides an intelligent fairing system based on three independently controlled sets of shape memory alloy (SMA) wires. The system employs an innovative single-set activation mode, ensuring that only one set of SMA wires is active at any given time, while the other two remain in a softened state, thus achieving precise and controllable fairing shape adjustment. The fairing body is made of flexible TPU composite material (elastic modulus 45 MPa) and thermally conductive silicone. The system integrates three sets of arranged SMA drive units (each with a diameter of 0.5 mm). Each set uses a specially formulated nickel-titanium alloy wire to achieve different driving characteristics: The first set (high-speed set): nickel-titanium-niobium alloy wire containing 5% niobium, with a phase transition temperature of 85°C after heat treatment at 350°C. The second set (medium-speed set): standard-ratio nickel-titanium alloy wire, cold-drawn, with a phase transition temperature of 75°C. The third set (low-speed set): nickel-rich nickel-titanium alloy wire, solution-annealed, with a phase transition temperature controlled at 65°C. Its austenitic elastic modulus of 25 GPa (working state) is 12.5 times that of the martensitic state (2 GPa) (non-working state), ensuring that the non-activated group does not affect the natural deformation of the TPU fairing. Each group is spaced 40 mm apart, with the front end fixed to the rigid frame and the rear end connected to the deformable TPU fairing.

[0131] During the acceleration of the spacecraft:

[0132] Low-speed stage (5-8m / s): Activate the third group (1.5A current), heat to 65℃ within 15 seconds to produce 2% deformation. At this time, the surface scales maintain the initial state (radius of curvature 8mm, tilt angle 50°) due to the low flow rate.

[0133] Medium speed stage (8-12m / s): Switch to the second group (2.5A current), heat up to 75℃ within 12 seconds to produce 4% deformation, the scales start to respond, the temperature rises to 55℃, the radius of curvature is reduced to 7mm, and the tilt angle is adjusted to 40°.

[0134] High-speed stage (>12m / s): Switch to the first group (3A current), heat up to 85℃ within 10 seconds to produce 6% deformation, scale temperature reaches 70℃, radius of curvature 5mm, tilt angle 30°, and drag coefficient is reduced by 22-25% under synergistic effect.

[0135] During the vehicle's deceleration process, the system employs a graded control strategy to achieve a smooth transition:

[0136] High-speed → Medium-speed deceleration phase:

[0137] The first set of currents was reduced from 3A to 1A and maintained, the SMA temperature was reduced from 85℃ to 60℃, 3% deformation was retained, the scale curvature radius was restored to 6mm, and the tilt angle was adjusted to 35°.

[0138] Medium speed → Low speed deceleration phase:

[0139] Switching to the third group of 1A current, the SMA temperature drops to 45℃, retaining 1% deformation, the scale curvature radius is restored to 7.5mm, and the tilt angle is 45°.

[0140] Complete shutdown phase: The entire group is powered off, and it fully resets within 15 seconds, with the scales returning to their initial state (radius of curvature 8mm, tilt angle 50°).

[0141] Under extreme conditions (20m / s): the scale temperature rises to 90℃, triggering a complete austenitic phase transformation, the radius of curvature drops to 3mm, forming a low-resistance continuous flow surface. After 500 cycles of testing, the strain retention rate is ≥98%, with no residual plastic deformation. The temperature of the thermally conductive silicone layer remains stable below 95℃, ensuring material reliability.

[0142] This single-group working mode ensures completely independent working states for the three groups of SMA filaments through precise timing control (2-second delay between groups) and temperature management (±1℃ accuracy).

[0143] The system achieves precise temperature control of ±2℃ through three-channel independent PWM modulation (100Hz, ±0.1A) combined with a PID temperature control algorithm (Kp=1.2, Ti=15s, Td=2s), maintaining deformation error <2%, reset time deviation ±0.3s, and resistance change rate <1.5% over 2000 operating cycles. This innovative single-group activation mode, working in conjunction with the passive adjustment of biomimetic scales, ensures excellent performance with rapid response (<15s) and 42% energy consumption reduction across the entire operating range (5-20m / s).

[0144] The intelligent monitoring system detects the ratio of the three sets of SMA resistors (R1:R2:R3) in real time. When the deviation exceeds 8%, the dynamic compensation program is automatically started to maintain long-term stability with deformation consistency deviation <3%, reset accuracy ±0.5mm, and resistance change rate <1.8%.

[0145] The specially designed impact-resistant system can withstand impacts with a deformation of less than 5% on the fairing:

[0146] 1. Absorbs 80% of impact energy through stress-induced martensitic phase transformation.

[0147] 2. The resistance fluctuation detection threshold is set to 7%.

[0148] 3. Automatically triggers 1.5A repair current (60-65℃).

[0149] 4. 92% shape restoration is achieved within 45 seconds.

[0150] After 250 collision-repair cycles, the phase change enthalpy change rate was <4.5%, the curvature retention rate of the guide surface was >97%, and the functional integrity retention rate of the scale mechanism was 99%.

[0151] The biomimetic shark scale structure covering the surface of the fairing employs a three-layer gradient composite design: a TPU functional surface layer with V-shaped turbulence grooves (0.3mm, elastic modulus 50MPa), a flexible thermally conductive silicone intermediate layer containing 30wt% boron nitride filler (0.5mm, thermal conductivity 2.5W / mK), and a flat TPU base layer (0.3mm, elastic modulus 50MPa). Mechanical interlocking and thermal conductivity are achieved between the layers through laser-drilled micropores (0.1mm diameter, 2mm spacing). Three 0.2mm diameter nickel-rich passive SMA wires (NiTi-55, phase transition temperature 45℃) are embedded within the scales. When the flow rate exceeds 12 m / s, fluid friction causes the temperature of the flake substrate to rise to 70°C within 8 seconds, triggering an austenitic phase transformation in the passive SMA filaments. This generates a 3.5% shrinkage strain, causing the flake curvature radius to dynamically decrease from the initial 8 mm to 5 mm (at a rate of change of 0.375 mm / s), and the overall tilt angle to adjust synchronously from 50° to 30°. When the flow rate drops below 3 m / s, the flakes undergo environmental convection cooling (10°C / s) and the elastic recovery force of the TPU substrate (0.8 N / mm²) decreases. 2 Under the combined action of these mechanisms, the initial shape is completely restored within 10 seconds (reset accuracy ±0.2mm). This passive adjustment mechanism and the active control SMA drive system work together without interference through thermal isolation design (thermal resistance of the thermally conductive silicone layer is 0.5K / W), maintaining a tilt angle synchronization accuracy of ±1° even at extreme flow velocities of 20m / s. This composite scale structure can delay the boundary layer transition point by 15%-20%, achieving a drag reduction effect of up to 27% when combined with the active SMA system.

[0152] The design, which combines active control of three sets of SMA filaments with passive response of biomimetic scales, enables the fairing system to achieve a 50% increase in dynamic response speed and a 40% reduction in energy consumption over a wide speed range, while avoiding performance degradation caused by mechanical wear.

[0153] Example 2: Straight-line propulsion condition

[0154] Example 2 is based on Example 1. When the propeller travels straight, the speed is determined by 2. Controller 7 controls the speed of motor 1 (DC motor 1: rated voltage 24V DC, rated current 5A, rated power 120W, maximum speed up to 3600rpm) via PWM signal. The water flow speed is determined by impeller 2, and the rotation speed range of the guide vanes is 5m / s to 20m / s. The leads between motor 1 and controller 7 are arranged in junction box 9. The maximum change rate of the PWM duty cycle does not exceed 10% (i.e., the change per second cannot exceed ±5% of the current value to ensure system stability). The higher the PWM duty cycle, the higher the speed of 1 per unit time period. The guide vane rotation shaft is connected to the rotating component of the propeller, and its rotation speed is proportional to the frequency of the PWM signal. To achieve precise speed regulation, the PWM frequency should be limited to below 20kHz. Linear stepper motors 34 and 49 (rated current 1A / phase, 24V) consume approximately 24W. The rotation shaft of 1 drives the impeller 2 to rotate. After impeller 2 rotates, the water flow inside shell 4 rotates and moves forward along the guide vanes of impeller 2. The diameter of impeller 2 is slightly smaller than the inner diameter of shell 4 so that impeller 2 can fully drive the water flow inside shell 4 and form a relatively uniform jet flow. The distributor adopts a composite layered design: the first layer (near the impeller): a square opening directly connected to the jet inlet (280mm×280mm). The second layer: an involute opening, the angle of which should be controlled between 18° and 22° to reduce water flow resistance. The third layer: a circular opening (150mm×150mm) to facilitate uniform water flow distribution. After passing through the distributor, nine jets are formed. The flow velocity sensors 24 in the nine channels of the distributor (using high-precision surface acoustic wave velocity sensors, with a measurement range of 0-30m / s and a response time of 5ms) will feed back the measured flow velocity to the controller 7 in real time. The formed jet 39 will enter the intelligent guide shroud through the funnel-shaped inlet 64. In the straight-line propulsion state, ideally, the output thrust of the guide vane is entirely controlled by the speed of impeller 2. Therefore, TPU 27 needs to be in an unstretched state, so that the pressure relief hole 38 is in a closed state. At this time, the shaft 35 of the linear stepper motor 34 is extended, pushing 33 to position 36, and the pressure relief hole 38 of the TPU is closed. To ensure the smoothest flow of fluid through TPU 46, the shaft 50 of the linear stepper motor 49 retracts. The shaft 50 drives the annular ring 48 to retract, and the annular ring 48 drives the annular hook 47 to move to the left. The annular hook 47 is fixed inside the TPU during the injection molding process of TPU 46. Therefore, the annular hook 47 pulls the outer ring of the circular TPU 46 outward, and the jet hole 54 on TPU 46 opens due to the stretching. The annular ring 48 moves to the left to position 51, at which time the opening (diameter) of the jet hole 54 reaches its maximum, and the water flow can pass through TPU 46 with almost no resistance. At this time, the actual jet velocity is measured by 87 and the signal is fed back to the controller 7 via the CAN bus.

[0155] In practical applications, the vortex generated by impeller 2 is a non-uniform flow field. The flow velocity varies across the nine channels of the nine-grid distributor, exhibiting a trend of high velocity in the center and low velocity at the edges. The velocity difference ranges from a maximum of 30% to a minimum of less than 5%. Therefore, the intelligent guide vane with high jet velocity needs to reduce the fluid jet velocity, while the intelligent guide vanes corresponding to the peripheral distributor channels 55-58 and 60-63 only require minor adjustments (the flow field is not absolutely uniform). This means ensuring that the velocity sensor 87 readings are the same across all nine guide vanes to guarantee the same thrust from the nine jets 92-100. Taking the lowest velocity among the nine jet velocity sensors 87 as a benchmark, the velocities of the other channels are adjusted to ensure the same thrust from 92-100, i.e., the same reading from the jet velocity sensor 87 across all nine guide vanes. For a high-velocity intelligent flow guide, to impede fluid flow through the TPU46, the shaft 50 of the linear stepper motor 49 extends. The shaft 50 drives the annular ring 48 to extend (move to the right), and the annular hook 47 follows the annular ring 48 to the right (the TPU46 has good elasticity and rebound characteristics). Due to the retraction, the diameter of the jet orifice 54 on the TPU46 decreases, reducing the effective fluid permeation area of ​​the TPU46. At this time, the reading of the jet velocity sensor 87 (jet flow rate) will decrease. A portion of the fluid is blocked at the funnel-shaped inlet 64, causing the flow rate to slow down, and the reading of the flow rate sensor 24 decreases. With the impeller 2 rotating at a constant speed, the vortex flow rate generated by the impeller 2 is constant. Since less water flows through this diversion channel, the reduced water flow will transfer to the remaining diversion channels, causing the reading of the flow rate sensor 24 in the remaining diversion channels to increase. It is unacceptable for a change in flow velocity in one channel to cause a change in flow velocity in the remaining channels. Therefore, it is necessary to ensure that the real-time flow velocity measured by the flow velocity sensor 24 in each branch channel is equal to the calibrated flow velocity of the flow velocity sensor 24. Therefore, when the annular ring 48 moves to the right and the diameter of the jet orifice 54 decreases, the annular retainer 33 needs to be moved to the right to stretch the TPU 27, thereby increasing the diameter of the pressure relief orifice 38 and increasing the pressure relief flow rate. This causes the reading of the flow velocity sensor 24 to gradually increase as the diameter of the pressure relief orifice 38 increases until the reading of the flow velocity sensor 24 increases to the calibrated flow velocity. Changes in the flow velocity reading of the flow velocity sensor 24 will cause a small change in the flow velocity reading of the jet velocity sensor 87. Therefore, the annular ring 48 will adjust its position so that the flow velocity of the jet velocity sensor 87 is once again equal to the given jet velocity. The entire process conforms to the principle. Figure 22 The negative feedback regulation is shown. The regulation process is the same for the intelligent flow guides corresponding to other flow channels. The regulation of each intelligent flow guide is independent of each other and does not interfere with each other's flow velocities.

[0156] When the vehicle needs to decelerate rapidly or stop abruptly, the impeller 2, due to its inertia, cannot significantly reduce speed or stop in a short time. Therefore, the intelligent deflectors are needed to assist in deceleration. When the vehicle needs to decelerate urgently, the shafts 50 of the nine intelligent deflectors 49 will extend, causing the annular ring 48 to be positioned between positions 51 and 52. Figure 8 b) The TPU rebounds, causing the diameter of the jet orifice 54 to decrease, obstructing water flow through the TPU 46. To increase the reading of the flow sensor 24 and restore it to the calibrated flow rate, the shaft 35 of the linear stepper motor 34 retracts (moves to the right), causing the annular retainer 33 to stretch and release the TPU 27. The annular retainer 33 moves to the center of the stroke endpoints 36 and 37. Figure 11 (b) The diameter of the pressure relief hole 38 increases, forming a pressure relief flow 66. The pressure relief flow 66 is perpendicular to the direction of the vehicle's movement. The pressure relief flows 66 in all directions are equal in size and opposite in direction, and the pressure relief thrust cancels each other out, not affecting the vehicle's straight-line movement. The position of the annular ring 48 can be dynamically adjusted according to the required degree of deceleration, achieving different levels of deceleration. The closer the annular ring 48 is to position 51, the slower the deceleration; conversely, the closer it is to position 52, the faster the deceleration.

[0157] Example 3: Thruster Turning Condition

[0158] Example 3 is based on Example 1. The thruster turning is achieved based on the straight-line conditions of Example 2. Turning and reversing are achieved by changing the jet velocity of each intelligent deflector under straight-line conditions. When the thruster turns horizontally, the thrust of each intelligent deflector is changed by adjusting the deformation of TPU27 and TPU46 of the nine intelligent deflectors (before adjustment, the aircraft is in the straight-line navigation state of Example 2, and the thrust at 92-100 is the same). When the thruster turns left relative to the forward direction, the output thrust on the 92-94 side remains unchanged compared to the straight-line thrust (the reading of jet velocity sensor 87 remains unchanged), the output thrust on the 95-97 side decreases compared to the 92-94 side (the reading of jet velocity sensor 87 decreases), and the output thrust on the 98-100 side decreases compared to the 95-97 side (the reading of jet velocity sensor 87 decreases). At this time, the output end of the intelligent deflector will generate a directional torsional torque 102 relative to the axis 101. The output thrust is controlled by adjusting the positions of the annular ring 48 and the annular retainer 33, according to... Figure 22 Real-time negative feedback adjustment will be implemented. The greater the decrease in flow velocity 87 between 95-97 and 92-94, and between 98-100 and 95-97, the larger the thruster 102 will be, and the faster the turn will be. Conversely, when the thruster makes a horizontal right turn, the thrust of 98-100 > the thrust of 95-97 > the thrust of 92-94, thus generating a torque opposite to that of 102.

[0159] When the thruster rises, the output thrust on sides 94, 97, and 100 remains unchanged compared to the thrust during straight-line travel (the reading on sensor 87 remains constant). The output thrust on sides 93, 96, and 99 decreases compared to sides 94, 97, and 100 (the reading on jet velocity sensor 87 decreases, and the readings on 87 are the same for sides 93, 96, and 99). The output thrust on sides 92, 95, and 98 further decreases compared to sides 93, 96, and 99 (the reading on jet velocity sensor 87 further decreases, and the readings on 87 are the same for sides 92, 95, and 98). At this time, the output end of the intelligent guide vane will generate a torsional torque of 104 relative to axis 103. Conversely, when the thruster descends, the thrust of (92; 95; 98) > (93; 96; 99) > (94, 97, 100) > (94, 97, 100), generating a torque in the opposite direction to 104.

[0160] When the thruster rises to the upper left relative to the forward direction, control the thrust of (94) > (93; 97) > (92; 96; 100) > (95; 99) > (98). When descending to the lower right, control the thrust of (94) < (93; 97) < (92; 96; 100) < (95; 99) < (98). When rising to the upper right, control the thrust of (100) > (99; 97) > (98; 96; 94) > (95; 93) > (92). When descending to the lower left, control the thrust of (100) < (99; 97) < (98; 96; 94) < (95; 93) < (92).

[0161] All thrust control is based on coordinated stretching / releasing control of the pressure relief TPU and the jet TPU. See the principle description for details. Figure 22 Explanation.

[0162] Key technical points of this invention:

[0163] (1) Structural design of a method and device for achieving independent control of the flow velocity of each jet in a multi-jet array based on a single propulsion source (one rotating motor 1):

[0164] The fluid is divided into several channels by a splitter. Then, TPUs with holes are set at the inlet side and outlet interface of the guides connected to each channel. By adjusting the stretching of the TPU, the pressure relief flow rate and the jet flow rate can be controlled. This ensures that the jet flow rate can be controlled and that the inlet flow rate of the guide is not affected by the TPU adjustment at the outlet end (adjusting the stretching of the TPU at the pressure relief end). In this way, it will not affect the inlet flow rate of other smart guides in the array.

[0165] The entire intelligent diverter + splitter structure was designed to accommodate the installation of variable TPUs.

[0166] (2) The coordinated regulation mechanism of the pressure relief end TPU and the jet end TPU, the process is described in the principle. Figure 22 .

[0167] (3) Shape memory alloy (SMA) is used as the adjustment mechanism for adjusting the shape of the fairing, replacing the traditional mechanical adjustment device. The SMA wire is bent by actively heating it with electricity, thereby changing the shape of the fairing. The deformation adjustment of the fairing is achieved by the thermal conductive layer (silicone) + thermal insulation layer (TPU) + glass fiber (rigid).

[0168] (4) Shape memory alloy (SMA) is used as the variable biomimetic shark scales on the surface of the fairing. The mechanical fixation and thermal conductivity are achieved by combining three layers of gradient materials: TPU functional layer (with V-groove) + high thermal conductivity silicone intermediate layer (30wt% boron nitride) + TPU elastic base layer and laser micro-hole interlocking (0.1mm aperture, 2mm spacing).

[0169] (5) Passive-active collaborative driving mechanism

[0170] Passive SMA filament (NiTi-55, diameter 0.2mm): Relies on fluid frictional heat to trigger phase change (45℃), achieving zero-energy passive regulation (curvature radius 8mm→5mm). Active SMA system: Independently controlled constant current source, avoids interference through thermal isolation design (low thermal conductivity TPU), and features collaborative working logic between active and passive regulation systems.

[0171] (6) Dynamic response and reset accuracy

[0172] Rapid response: Deformation completes within 8 seconds (0.375mm / s rate), and environmental cooling combined with TPU elasticity enables 10-second reset (±0.2mm accuracy). Protection points: Mapping relationship between SMA phase change temperature and flow rate, and reset accuracy control method.

[0173] (7) By using multiple sets of SMA with different component ratios, the multi-segment deformation range adjustment of the fairing can be achieved.

[0174] (8) A soft and elastic TPU material shroud (providing the flexibility and resilience required for deformation), combined with rigid glass fiber to give it a certain degree of rigidity (as a reinforcing skeleton to prevent the TPU from tearing under large deformation).

[0175] It provides directional stiffness and retains 15° bending freedom in the warp and weft directions for free bending, forming a novel deformable composite fairing structure.

[0176] (9) Synergistic Topology of TPU-Glass Fiber-SMA: Through material layout and structural design, thermoplastic polyurethane (TPU), glass fiber reinforcement layer and shape memory alloy (SMA) are combined in a specific geometric arrangement to form an intelligent composite structure that can synergistically respond to external stimuli (such as heat and force). This achieves efficient force transmission, controllable deformation and rapid reset.

[0177] (10) TPU matrix: Provides elastic deformation and resilience, wraps glass fiber and SMA, buffers stress concentration, and achieves compliant deformation.

[0178] (11) Fiberglass mesh: enhances structural rigidity, limits excessive deformation, guides the direction of deformation, and prevents local tearing of TPU during SMA shrinkage.

[0179] (12) SMA yarn: Heat-driven active deformation (heat shrinkage) Through pre-stretching and arrangement design, the shrinkage force is efficiently converted into directional deformation of the overall structure.

[0180] The main innovative points of this invention are as follows:

[0181] 1. Structural design of a method and device for achieving independent controllable flow velocity of each jet within a multi-jet array based on a single propulsion source (one rotating motor 1).

[0182] 2. Actively adjustable SMA multi-segment deformable underwater thruster fairing

[0183] 3. Based on passively adjustable SMA deformable underwater biomimetic shark scale design (applied to underwater thruster fairing)

[0184] 4. Cooperative Mechanism of Active / Passive Deflector System

[0185] 5. The structure, materials, and layout are all other innovations derived from the above-mentioned innovations.

Claims

1. A highly maneuverable and low-energy-consumption array-type underwater thruster, characterized in that, The device includes a pump-jet generator, a flow divider, and an intelligent flow guide. The pump-jet generator and the flow divider together form the front end of the propeller, while the intelligent flow guide forms the rear end. The pump-jet generator drives an impeller via a rotary motor, causing the surrounding water flow to swirl and generate a main jet. The flow divider has an internal isolation structure to evenly divide the main jet into multiple independent sub-jet streams. Each sub-jet stream enters the intelligent flow guide and is guided to form propulsion power. Multiple intelligent flow guides are connected one-to-one with multiple channels of the flow divider to convert the fluid exiting the flow surface of the flow divider into an effective jet with adjustable flow rate. Each intelligent flow guide includes a jet end control mechanism and a pressure relief end control mechanism. The jet end control mechanism is used to independently adjust the flow rate of the effective jet ejected from the flow guide. The pressure relief end control mechanism is used to maintain a constant flow rate at the inlet of the flow guide by releasing part of the water flow when adjusting the effective jet flow rate, so as to avoid interfering with the flow field of other flow guides.

2. The highly maneuverable and low-energy-consumption array-type underwater thruster according to claim 1, characterized in that, The jet end control mechanism includes: an annular thermoplastic polyurethane elastomer film and a linear stepper motor. The annular thermoplastic polyurethane elastomer film has multiple deformable holes evenly distributed on it. The output shaft of the linear stepper motor is connected to the outer edge of the thermoplastic polyurethane elastomer film through a linkage mechanism, which is used to change the aperture of the holes by stretching or releasing the thermoplastic polyurethane elastomer film, thereby adjusting the flow rate of the effective jet.

3. The highly maneuverable and low-energy-consumption array-type underwater thruster according to claim 1, characterized in that, The pressure relief control mechanism includes: an annular thermoplastic polyurethane elastomer membrane, a linear stepper motor, and an annular pressure relief hole; the annular thermoplastic polyurethane elastomer membrane is disposed on the side of the funnel-shaped structure at the inlet of the flow guide, and has an oblique pressure relief hole on it; the output shaft of the linear stepper motor is connected to an annular retainer, which is used to change the aperture of the pressure relief hole by stretching or releasing the annular thermoplastic polyurethane elastomer membrane; the annular pressure relief hole is disposed on the stainless steel shell of the flow guide, corresponding to the pressure relief hole on the annular thermoplastic polyurethane elastomer membrane, and is used to spray the discharged water flow uniformly in a direction perpendicular to the axis of the thruster in a 360° direction, so that the resultant force of the pressure relief thrust is zero.

4. The highly maneuverable and low-energy-consumption array-type underwater thruster according to claim 1, characterized in that, The intelligent flow deflector is externally wrapped with an intelligent flow deflector cover, which is made of flexible thermoplastic polyurethane material and has multiple sets of shape memory alloy wires embedded inside. By applying electricity to different sets of shape memory alloy wires and heating them, they undergo phase change and shrinkage, thereby actively adjusting the curvature and / or tilt angle of the flow deflector cover.

5. The highly maneuverable and low-energy-consumption array-type underwater thruster according to claim 4, characterized in that, The multiple sets of shape memory alloy wires include at least three sets, each set having a different phase transition temperature, thereby enabling stepped deformation output under different temperatures and current excitations, achieving multi-level adjustment of the shroud shape.

6. The highly maneuverable and low-energy-consumption array-type underwater thruster according to claim 4, characterized in that, The shape memory alloy wire is wrapped in flexible thermally conductive silicone and externally encapsulated with a flexible thermoplastic polyurethane material with low thermal conductivity to achieve rapid heating response and thermal isolation from the passive biomimetic scale system.

7. The highly maneuverable and low-energy-consumption array-type underwater thruster according to claim 4, characterized in that, The intelligent air deflector adopts a composite layered structure, including an outer and inner flexible thermoplastic polyurethane layer, and a fiberglass woven mesh layer sandwiched in the middle. The fiberglass woven mesh layer is used to provide structural rigidity and prevent the flexible thermoplastic polyurethane layer from tearing, while retaining the bending freedom for the shape memory alloy wire to be stretched and deformed. The outer surface of the intelligent air deflector is covered with biomimetic shark scales, which adopt a three-layer gradient composite structure, including: a flexible thermoplastic polyurethane functional surface layer with V-shaped grooves, a high thermal conductivity silicone intermediate layer with embedded passive shape memory alloy wires, and a flat flexible thermoplastic polyurethane elastic base layer. The passive shape memory alloy wires are not connected to an external power source, and their deformation is triggered by the frictional heat generated when the fluid flows through the V-shaped grooves, thereby realizing passive and adaptive adjustment of the scale shape.

8. The highly maneuverable and low-energy-consumption array-type underwater thruster according to claim 1, characterized in that, The internal isolation structure of the diverter includes isolation plates and flow-gathering channels. The isolation plates are arranged in a nine-square grid pattern, which can divide the jet of the pump-jet generator into nine uniform parts. The incident flow surface of the flow-gathering channel is square, and the exit flow surface is circular. The square and circular interfaces are gradually transitioned to reduce water flow resistance and improve fluid energy utilization efficiency. A wire conduit is arranged at the front end of the diverter, which connects the intelligent flow guide to the communication signal of the control box. Multiple flow velocity sensors are arranged in the nine-square grid formed by the isolation plates to monitor the flow velocity of the current channel. The flow velocity sensors adopt SAW flow velocity sensors.

9. The highly maneuverable and low-energy-consumption array-type underwater thruster according to claim 1, characterized in that, The thruster also includes a control system that employs a PID negative feedback control strategy. PID controller 1 is used to control the motor speed of the pump-jet generator according to the target speed. The second PID controller is used to control the pressure relief end regulating mechanism based on the reading of the flow velocity sensor in the distributor, so as to maintain a constant inlet flow velocity in each channel. The third PID controller is used to control the jet end adjustment mechanism based on the reading of the flow rate sensor at the outlet of the intelligent flow guide, so as to accurately adjust the final flow rate of each effective jet.

10. The highly maneuverable and low-energy-consumption array-type underwater thruster according to claim 1, characterized in that, The pump-jet generator, the diverter, and the intelligent diverter adopt a modular design. The intelligent diverter is connected and fixed to the diverter via a slot, which facilitates disassembly, maintenance, and upgrades.

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