Variable impulse method for manta ray vehicle attitude control by internal shunting

Abstract

The application provides a variable impulse method for manta ray-like vehicle attitude control through bypass internal flow distribution, a propeller serving as a propelling system and a flow distributor with adjustable position arranged at an outlet end of a power duct module are fused and designed, axial water flow generated by the single propeller is directly used as propelling power and attitude control direct power, the flow of each jetting outlet can be adjusted without changing the propeller rotating speed through position adjustment of the flow distributor arranged at the outlet end of the power duct module, the impulse of water flow of upper and lower jetting outlets is quickly changed, upper and lower thrust difference is formed on the bionic body, the pitching moment is changed without changing the propelling process, the attitude adjustment of the bionic vehicle is accurately realized, and the system efficiency, dynamic response and task adaptability are coordinately improved on the basis of keeping the original propelling efficiency advantage.

Description

Technical Field

[0001] This invention relates to the field of hydrodynamic testing and mechanical measurement technology, and more specifically, to a variable impulse method for attitude control of a manta ray-inspired aircraft by diverting flow within a duct. Background Technology

[0002] In the fields of hydrodynamic testing and mechanical measurement, biomimetic vehicle technology is continuously evolving towards higher efficiency, greater maneuverability, and greater autonomy. Especially in the field of biomimetic robotics, vehicle designs mimicking the shape and movement mechanisms of marine organisms offer significant advantages in terms of fluid resistance, maneuverability, and energy utilization. Among these, the manta ray, with its flat, streamlined body and wide, delta-like wing, offers several advantages for underwater navigation. Firstly, it provides highly efficient hydrodynamic performance; the manta ray's body shape reduces fluid resistance, improving propulsion efficiency in water and resulting in superior range or speed with the same power. Secondly, it offers high stealth; its shape significantly reduces fluid noise during movement and minimizes radar and sonar cross-sections, making it suitable for scenarios requiring high stealth, such as underwater detection and low-altitude reconnaissance. Thirdly, it provides high stability; the wide body offers better attitude stability, making it easier to maintain its trajectory in complex flow fields, such as turbulence and water disturbances.

[0003] However, how to achieve rapid, precise, and low-energy active control of the vehicle's attitude, especially its pitch direction, while mimicking the shape of a manta ray and maintaining its propulsion efficiency and simple structure remains a significant challenge restricting the development of biomimetic vehicle technology.

[0004] Existing technical solutions often require separating the attitude control system from the propulsion system. First, the separate propulsion system, attitude control system, and their associated drive, sealing, and control systems not only increase the platform's mechanical complexity, overall weight, and potential failure points, but also reduce system reliability. Second, separating the attitude control system from the propulsion system requires a separate power unit for attitude control, which continuously consumes power to balance disturbances even when maintaining a steady attitude. The resulting jet stream may interfere with the main propulsion flow field, leading to a decrease in overall propulsion efficiency and making it difficult to achieve performance optimization at the system level. This increases the complexity of the structural layout and creates competition and redundancy in energy and control, making it difficult for biomimetic vehicles to simultaneously meet multiple mission requirements such as long endurance, high maneuverability, and strong adaptability.

[0005] Therefore, there is a need to develop a technical solution that can easily achieve attitude control of manta ray-inspired aircraft while taking into account both propulsion efficiency and attitude control accuracy. Summary of the Invention

[0006] The purpose of this invention is to overcome at least one of the defects (deficiencies) of the prior art and to provide a variable impulse method for attitude control of a manta ray-inspired aircraft by duct diversion.

[0007] One aspect of the present invention provides a variable impulse method for attitude control of a manta ray-inspired vehicle through flow diversion within a duct, specifically, the manta ray-inspired vehicle includes: A biomimetic body, wherein the biomimetic body has a streamlined shape; A power duct module is axially disposed inside the bionic body, and the power duct module includes a through duct. A propeller is provided at the inlet end of the duct to propel the bionic body and generate axial water flow. A flow distributor is movably disposed at the center of the outlet end of the duct. The flow distributor is used to receive the axial water flow and split it through at least two independent jet outlets and out of the bionic body. By controlling the position of the flow distributor in the duct, the velocity and momentum of the water jets ejected from each of the jet outlets are distributed and changed without changing the propeller speed, thereby generating impulse between the jet outlets and producing a pitching moment perpendicular to the axis of the biomimetic body.

[0008] In this technical solution, the propeller of the propulsion system, integrated with a power duct module within the biomimetic body, is combined with an adjustable flow distributor located at the duct outlet. This design integrates the axial water flow generated by the single propeller as both propulsion power and direct power for attitude control, achieving deep integration of propulsion and attitude control functions. Furthermore, no additional power unit is required; power regulation is achieved solely through flow distribution, reducing energy loss and response time, and indirectly improving endurance. Specifically, by adjusting the position of the flow distributor at the duct outlet, the flow rate at each jet outlet can be adjusted without changing the propeller speed. By rapidly altering the impulse of the water flow at the upper and lower jet outlets, a thrust difference is created on the biomimetic body, thereby changing the pitch moment without altering the propulsion process. This allows for precise attitude adjustment of the manta ray-inspired vehicle, adapting to complex motion requirements. While maintaining the original propulsion efficiency advantage, this design achieves a synergistic improvement in system performance, dynamic response, and mission adaptability.

[0009] Furthermore, the power duct module includes an inlet duct and at least two outlet ducts that are interconnected. One end of the inlet duct is provided with a propeller, and the axis of the inlet duct coincides with or is parallel to the central axis of the bionic body. Each outlet duct is connected to a corresponding jet outlet. The inlet duct passes through the center of gravity of the bionic body, and the axes of the outlet ducts do not pass through the center of gravity of the bionic body.

[0010] In this technical solution, by constructing the power duct module as an interconnected inlet duct and at least two outlet ducts, and ensuring that the axis of the inlet duct passes through the center of gravity of the biomimetic body, the propulsion axis is spatially aligned with the vehicle's inertial axis. This allows the axial thrust generated by the propeller to act directly on the center of gravity, fundamentally avoiding unwanted additional pitch or yaw moments caused by the propulsion force not passing through the center of gravity. This reduces the disturbance compensation burden on the attitude control system and ensures the overall stability of the vehicle's propulsion and attitude adjustment. Simultaneously, the off-center arrangement of the outlet duct axis gives the control thrust generated by each jet outlet a defined lever arm relative to the center of gravity. When the flow distributor adjusts the flow distribution at each outlet, the resulting difference in water flow can be efficiently converted into pitch or yaw control moments around the center of gravity, avoiding coupling interference caused by thrust eccentricity and significantly improving the linearity and predictability between control commands and response moments. Furthermore, the layout of the inlet duct that crosses the center of gravity integrates the vehicle's mass distribution with the main duct, optimizing internal space utilization and mass balance, and improving payload capacity and energy efficiency. Meanwhile, the offset design of the outlet duct provides a stable torque amplification mechanism for attitude control while maintaining propulsion purity, enabling the vehicle to achieve more significant control effects with a smaller flow distribution adjustment, thus improving the dynamic quality of attitude adjustment and energy utilization efficiency.

[0011] Furthermore, the flow distributor is placed at the connection between the inlet culvert and the outlet culvert. The ends of all the outlet culverts away from the jet outlet are simultaneously connected to the flow distributor, and the flow area of ​​the outlet culvert is adjusted by the flow distributor to distribute and change the velocity and momentum of the water jetting from the corresponding jet outlet of each outlet culvert.

[0012] In this technical solution, by placing the flow distributor at the connection between the inlet duct and the outlet duct, and connecting the ends of all outlet ducts furthest from the jet outlet to the flow distributor, the flow distributor can synchronously adjust the flow area of ​​multiple outlet ducts. This allows for convenient adjustment of the flow distribution at each jet outlet to meet a preset proportional relationship, improving the synchronization and coordination of attitude control. Secondly, centralized control is implemented at the connection between the inlet and outlet ducts using a single flow regulator. This not only ensures that the water flow is pre-distributed before entering each outlet duct, reducing energy dissipation and improving the transmission efficiency of propulsion energy, but also reduces the number of moving parts, simplifies the structure, and improves the integration and reliability of the flow distribution system.

[0013] Furthermore, the manta ray-inspired vehicle also includes a drive mechanism, which is connected to the flow distributor and used to drive and change the position of the flow distributor in the duct. By introducing a drive mechanism connected to the flow distributor, and through the precise control of the flow distributor's position in the duct, the flow distributor can generate precise movement, thereby accurately adjusting the flow area ratio at the jet outlet. This transforms the abstract pitch torque requirement into a controllable difference in water flow rate at the jet outlet, significantly improving the accuracy and consistency of pitch attitude control for the biomimetic subject.

[0014] Furthermore, the biomimetic body has a flat, streamlined, manta ray-like shape, including an axially arranged head, tail, and symmetrically arranged side wings on both sides of the biomimetic body, with a tail fin on the upper surface of the tail. By adopting a low-drag configuration such as the flat, streamlined, manta ray-like shape, and integrating the symmetrically arranged side wings and the tail fin on the upper surface of the tail, the pressure drag and induced drag of the vehicle at low and medium speeds are significantly reduced, improving hydrodynamic efficiency and enabling higher speeds or longer ranges with the same propulsion power. The addition of the tail fin on the upper surface of the tail provides additional pitch stabilizing torque by utilizing the incoming flow generated when the vehicle is moving forward, giving the biomimetic body better heading control in constant depth cruise, improving the vehicle's motion stability in complex flow fields, and effectively reducing the steady-state adjustment burden of the flow distributor.

[0015] Furthermore, the inlet duct smoothly transitions to the head of the bionic body, and the outlet duct faces the tail of the bionic body; Starting from the flow distributor, the axial diameter of the outlet duct gradually decreases towards the tail, and the outlet duct forms an angle of no more than 90° with the central axis of the biomimetic body.

[0016] In this technical solution, by smoothly transitioning the inlet duct to the head of the biomimetic body, setting the outlet duct towards the tail and gradually reducing its axial diameter from the flow distributor, and simultaneously making the outlet duct form an angle of no more than 90° with the central axis of the body, the synergistic improvement of jet kinetic energy density and energy utilization efficiency is achieved. Specifically, the smooth transition between the inlet duct and the head effectively suppresses flow separation and energy loss in the inlet area, improving the inlet duct's water intake efficiency. Simultaneously, the tapering design of the outlet duct diameter allows the water flow to undergo a controllable acceleration process before discharge, significantly increasing the jet's outlet velocity and kinetic energy density. This enables the generation of greater reaction thrust at the same flow rate, enhancing the propulsion system's power output efficiency. The angle of no more than 90° between the jet outlet and the central axis results in a jet direction that is obliquely backward. Its reaction force can be decomposed into an axial forward thrust component and an attitude control component perpendicular to the axial direction. Thus, the momentum generated during the pitching moment contributes to both control force and effective thrust, achieving partial reuse of attitude control energy and propulsion energy, significantly improving overall energy efficiency under high-maneuverability conditions.

[0017] In one embodiment, the bionic body is provided with two jet outlets symmetrically arranged based on the central axis of the bionic body, and the jet outlets are respectively disposed on the upper and lower surfaces of the bionic body.

[0018] In this technical solution, the symmetrical arrangement of the jet outlets on both sides of the central axis ensures that the reaction forces generated by the upper and lower nozzles are completely canceled out in the horizontal direction. This ensures that no undesirable yaw or roll disturbance torques are generated during attitude adjustment, improving the decoupling and motion stability of the attitude control channel. At the same time, the arrangement of the jet outlets on the upper and lower surfaces ensures that the reaction forces of the upper and lower nozzles have a clear vertical lever arm relative to the center of gravity of the vehicle. When the flow distributor adjusts the flow distribution of each outlet, the resulting difference in water flow can be efficiently converted into a pure pitch control torque, avoiding coupling disturbances caused by thrust eccentricity or asymmetrical layout. This significantly improves the linearity and predictability between pitch control commands and response torques. In addition, this symmetrical layout ensures that the reference flow rates of the upper and lower nozzles are equal during constant depth cruise, maintaining pitch balance without continuous deflection of the flow distributor, effectively reducing the steady-state adjustment burden and energy consumption of the attitude control system.

[0019] Furthermore, the flow distributor is a smooth wedge-shaped structure. One end of the wedge-shaped structure is connected to the bionic body through its pivot, and the other end extends radially along the duct. The length of the wedge-shaped structure matches the end face diameter of the outlet end of the duct, and the thickness of the wedge-shaped structure gradually decreases from the pivot to the radially extending end. The flow distributor's rotating shaft is set perpendicular to the axis of the duct's inlet end, allowing the flow distributor to deflect vertically.

[0020] In this technical solution, efficient, low-loss, and precise control of the flow field at the tail of the duct is achieved by optimizing the shape of the flow distributor and its assembly with the duct outlet. Specifically, the use of a wedge structure with a smooth surface and a gradually varying thickness profile significantly reduces the frictional resistance of the water flow over the distributor surface, reduces the total pressure loss introduced by the flow regulator itself, and improves the overall hydraulic efficiency of the duct propulsion system. Secondly, the matching design of the radial length and the diameter of the duct end face ensures that the wedge structure can divide the tail of the duct into two independent and well-sealed jet outlets at any deflection angle, preventing water from leaking through the lateral gaps without control, and significantly improving the execution accuracy of flow distribution. At the same time, the arrangement of the rotating shaft perpendicular to the duct axis allows the wedge structure to achieve continuous deflection in the vertical direction with minimal rotational inertia, reducing energy consumption while improving the dynamic response speed of attitude adjustment.

[0021] Furthermore, the connection end of the wedge structure and the rotating shaft is embedded in the bionic body. The wedge structure is rotatably connected to the bionic body, and the connection between the wedge structure and the bionic body is sealed without affecting the rotation effect of the wedge structure, thereby forming a smooth duct surface at the connection between the wedge structure and the bionic body.

[0022] In this technical solution, a rotational connection is achieved by embedding the wedge-shaped structure and the connecting end of the rotating shaft into the biomimetic body. The connection is sealed while ensuring its rotational function, creating a smooth and continuous duct wall, thus achieving a low-disturbance transition between the moving component and the fixed body. Specifically, this design allows the wedge-shaped structure to flexibly deflect within the duct to adjust flow distribution, while completely eliminating gaps at its connection with the body. This effectively avoids momentum loss and control deviation caused by water leakage through the rotational gap, significantly improving the execution accuracy and energy utilization efficiency of flow distribution. The smooth and continuous duct wall eliminates interference caused by structural abrupt changes, keeping the flow field at the jet outlet stable and controllable, and improving the linearity between attitude control commands and response torque. Furthermore, the sealed structure isolates the rotating mechanism from external water flow, preventing silt intrusion and biological adhesion from causing wear and jamming of the moving parts, thus improving the long-term reliability of the system in complex underwater environments.

[0023] Another objective of this invention is to provide a manta ray-inspired vehicle that can achieve underwater attitude control using the variable impulse method of flow diversion within the duct provided by this technical solution. Specifically, after obtaining the target attitude of the biomimetic subject, the required pitch torque is calculated through analysis. Based on this torque, the target setting position of the flow distributor at the duct outlet can be determined, and the flow distributor is directionally adjusted to the target position to change the flow distribution at each jet outlet, thereby generating the required pitch torque to achieve attitude adjustment. This transforms the abstract pitch torque requirement into the position setting of the flow distributor in the attitude control device, and precisely drives it to the designated position, achieving an organic combination of dynamic calculation and precise position control. This significantly improves the accuracy of attitude control and the consistency of dynamic response of the biomimetic vehicle. At the same time, this method operates in parallel and independently with the propeller's own speed control unit, and attitude correction can be completed synchronously without interrupting the propulsion process. This achieves complete decoupling of the propulsion function and attitude control function in the time dimension, improving system coordination and control efficiency when multiple tasks are executed in parallel.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. A variable impulse method for attitude control of a manta ray-inspired vehicle through flow diversion within a duct is provided. This method integrates a propeller-driven power duct module within the biomimetic body with an adjustable flow distributor located at the duct outlet. The axial water flow generated by the single propeller serves as both propulsion and attitude control power, achieving deep integration of propulsion and attitude control functions. Furthermore, no additional power unit is required; power regulation is achieved solely through flow distribution, reducing energy loss and response time, indirectly improving endurance. Specifically, by adjusting the position of the flow distributor at the duct outlet, the flow rate at each jet outlet can be adjusted without changing the propeller speed. By rapidly altering the impulse of the water flow at the upper and lower jet outlets, a thrust difference is created on the biomimetic body, thereby changing the pitch moment without altering the propulsion process. This allows for precise attitude adjustment of the manta ray-inspired vehicle, adapting to complex motion requirements. While maintaining the original propulsion efficiency advantage, this method achieves a synergistic improvement in system performance, dynamic response, and mission adaptability.

[0025] 2. A manta ray-inspired underwater vehicle is provided, which utilizes a variable impulse method involving flow diversion within a duct to control its underwater motion. Specifically, after acquiring the target attitude of the biomimetic subject, the required pitch torque is calculated and analyzed. Based on this torque, the target setting position of the flow distributor at the duct outlet is determined, and the flow distributor is directionally adjusted to this target position to change the flow distribution at each jet outlet, thereby generating the required pitch torque to achieve attitude adjustment. This transforms the abstract pitch torque requirement into the position setting of the flow distributor in the attitude control device, precisely driving it to the designated position. This achieves an organic combination of dynamic calculation and precise position control, significantly improving the accuracy of attitude control and the consistency of dynamic response for the biomimetic vehicle. Simultaneously, this method operates in parallel and independently with the propeller's own speed control unit, allowing for synchronous attitude correction without interrupting the propulsion process. This achieves complete decoupling of propulsion and attitude control functions in the time dimension, improving system coordination and operational efficiency during multi-task parallel execution. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a manta ray-inspired aircraft provided by the present invention.

[0027] Figure 2 This is a cross-sectional view of a manta ray-inspired aircraft provided by the present invention.

[0028] Figure 3 This is a schematic diagram of the wedge-shaped structure and its driving mode in the manta ray-inspired aircraft provided in Example 2.

[0029] Figure 4 This is a schematic diagram of the wedge structure in the manta ray-inspired aircraft provided in Example 2, when it is symmetrical, offset upwards, and offset downwards.

[0030] Figure 5 The velocity cloud diagrams are shown for the wedge structure in the manta ray-inspired vehicle provided in Example 2, when it is maintained in symmetry, upward offset, and downward offset. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below. Obviously, what is described is only a part of the embodiments of the present invention, and not all of the embodiments.

[0032] Example 1 This embodiment provides a variable impulse method for attitude control of a manta ray-inspired aircraft through flow diversion within a duct, and a manta ray-inspired aircraft using the same method. Specifically, as shown... Figure 1 The manta ray-inspired vehicle shown includes: Bionic body, the bionic body has a streamlined shape; The power duct module is axially disposed inside the bionic body. The power duct module includes a through duct. A propeller is provided at the inlet end of the duct to propel the bionic body and generate axial water flow. A flow distributor is movably disposed at the center of the outlet end of the duct. The flow distributor is used to receive the axial water flow and split it through at least two independent jet outlets and out of the bionic body. By controlling the position of the flow distributor in the duct, the velocity and momentum of the water jets ejected from each jet outlet are distributed and changed without changing the propeller speed, thereby generating impulse between the jet outlets and producing a pitching moment perpendicular to the axis of the biomimetic body.

[0033] Specifically, by changing the position of the flow distributor at the duct outlet, the flow rate at each jet outlet can be adjusted without changing the propeller speed. By rapidly changing the impulse of the water flow at the upper and lower jet outlets, a thrust difference is created on the biomimetic body, thereby changing its pitch moment without changing its propulsion process. This allows for precise attitude adjustment of the manta ray-inspired vehicle, adapting to complex motion requirements. While maintaining the original propulsion efficiency advantage, it achieves a synergistic improvement in system performance, dynamic response, and mission adaptability.

[0034] Furthermore, the power duct module includes an inlet duct and at least two outlet ducts that are interconnected. One end of the inlet duct is equipped with a propeller, and the axis of the inlet duct coincides with or is parallel to the central axis of the bionic body. Each outlet duct is connected to a corresponding jet outlet. The inlet duct passes through the center of gravity of the bionic body, and the axes of the outlet ducts do not pass through the center of gravity of the bionic body.

[0035] Specifically, by constructing the power duct module as an interconnected inlet duct and at least two outlet ducts, and ensuring that the axis of the inlet duct passes through the center of gravity of the biomimetic body, spatial alignment of the propulsion axis with the vehicle's inertial axis is achieved. This allows the axial thrust generated by the propeller to act directly on the center of gravity, fundamentally avoiding unwanted additional pitch or yaw moments caused by the propulsion force not passing through the center of gravity. This reduces the disturbance compensation burden on the attitude control system and ensures the overall stability of the vehicle's propulsion and attitude adjustment. Simultaneously, the off-center arrangement of the outlet duct axis gives the control thrust generated by each jet outlet a defined lever arm relative to the center of gravity. When the flow distributor adjusts the flow distribution at each outlet, the resulting difference in water flow can be efficiently converted into pitch or yaw control moments around the center of gravity, avoiding coupling interference caused by thrust eccentricity and significantly improving the linearity and predictability between control commands and response moments. Furthermore, the layout of the inlet duct that crosses the center of gravity integrates the vehicle's mass distribution with the main duct, optimizing internal space utilization and mass balance, and improving payload capacity and energy efficiency. Meanwhile, the offset design of the outlet duct provides a stable torque amplification mechanism for attitude control while maintaining propulsion purity, enabling the vehicle to achieve more significant control effects with a smaller flow distribution adjustment, thus improving the dynamic quality of attitude adjustment and energy utilization efficiency.

[0036] Furthermore, the flow distributor is placed at the connection between the inlet duct and the outlet duct. The ends of all outlet ducts furthest from the jet outlet are simultaneously connected to the flow distributor, and the flow area of ​​the outlet duct is adjusted by the flow distributor to distribute and change the velocity and momentum of the water jetting from the corresponding jet outlet of each outlet duct.

[0037] Specifically, by placing the flow distributor at the connection between the inlet and outlet culverts, and connecting the ends of all outlet culverts furthest from the jet outlets to the flow distributor simultaneously, the flow distributor can synchronously adjust the flow area of ​​multiple outlet culverts. This allows for convenient adjustment of the flow distribution at each jet outlet to meet a preset proportional relationship, improving the synchronization and coordination of attitude control. Secondly, centralized control is implemented at the connection between the inlet and outlet culverts using a single flow regulator. This not only ensures that the water flow is pre-distributed before entering each outlet culvert, reducing energy dissipation and improving the transmission efficiency of propulsion energy, but also reduces the number of moving parts, simplifies the structure, and improves the integration and reliability of the flow distribution system.

[0038] Furthermore, the manta ray-inspired vehicle also includes a drive mechanism, which is connected to the flow distributor and used to drive and change the position of the flow distributor in the duct. By introducing a drive mechanism connected to the flow distributor, the precise control of the flow distributor's position in the duct by the drive mechanism enables the flow distributor to generate precise movement, thereby accurately adjusting the flow area ratio at the jet outlet. This transforms the abstract pitch torque requirement into a controllable difference in water flow rate at the jet outlet, significantly improving the accuracy and consistency of pitch attitude control for the biomimetic subject.

[0039] Preferably, the biomimetic body has a flat, streamlined, manta ray-like shape, including an axially arranged head, tail, and symmetrically arranged side wings on both sides of the biomimetic body, with a tail fin on the upper surface of the tail. By adopting a low-drag configuration such as the flat, streamlined, manta ray-like shape, and integrating symmetrically arranged side wings and a tail fin on the upper surface of the tail, the pressure drag and induced drag of the vehicle at low and medium speeds are significantly reduced, improving hydrodynamic efficiency and enabling higher speeds or longer ranges with the same propulsion power. The addition of a tail fin on the upper surface of the tail provides additional pitch stabilizing torque by utilizing the incoming flow generated when the vehicle is moving forward, giving the biomimetic body better course maintenance capability in constant depth cruise, improving the vehicle's motion stability in complex flow fields, and effectively reducing the steady-state adjustment burden of the flow distributor.

[0040] Furthermore, the inlet duct smoothly transitions to the head of the bionic body, while the outlet duct faces the tail of the bionic body. Starting from the flow distributor, the axial diameter of the outlet duct gradually decreases towards the tail, and the outlet duct forms an angle of no more than 90° with the central axis of the biomimetic body.

[0041] Specifically, the smooth transition between the inlet duct and the head effectively suppresses flow separation and energy loss in the inlet area, improving the inlet duct's water intake efficiency. Simultaneously, the tapering design of the outlet duct diameter allows the water flow to undergo a controllable acceleration process before discharge, significantly increasing the jet's outlet velocity and kinetic energy density. This enables the generation of greater reaction thrust at the same flow rate, enhancing the propulsion system's power output efficiency. The angle of no more than 90° between the jet outlet and the central axis results in a jet direction that is obliquely backward. Its reaction force can be decomposed into an axial forward thrust component and an attitude control component perpendicular to the axial direction. Thus, the momentum generated during the pitching moment contributes to both control force and effective thrust, achieving partial reuse of attitude control energy and propulsion energy, significantly improving overall energy efficiency under high-maneuverability conditions.

[0042] Example 2 like Figures 1-5As shown, this embodiment also provides a biomimetic vehicle and an attitude adjustment device for the biomimetic vehicle based on ducted flow diversion, which differs from Embodiment 1 in that: The bionic body has two jet outlets symmetrically arranged based on the central axis of the bionic body, and the jet outlets are respectively located on the upper and lower surfaces of the bionic body.

[0043] Specifically, the symmetrical arrangement of the jet outlets on both sides of the central axis ensures that the reaction forces generated by the upper and lower nozzles are completely canceled out in the horizontal direction, preventing unwanted yaw or roll disturbance torques during attitude adjustment and improving the decoupling and motion stability of the attitude control channel. Simultaneously, the arrangement of the jet outlets on the upper and lower surfaces gives the reaction forces of the upper and lower nozzles a clear vertical lever arm relative to the vehicle's center of gravity. When the flow distributor adjusts the flow distribution of each outlet, the resulting difference in water flow can be efficiently converted into a pure pitch control torque, avoiding coupling disturbances caused by thrust eccentricity or asymmetrical layouts, and significantly improving the linearity and predictability between pitch control commands and response torques. Furthermore, this symmetrical layout ensures that the reference flow rates of the upper and lower nozzles are equal during constant depth cruise, maintaining pitch balance without continuous deflection of the flow distributor, effectively reducing the steady-state adjustment burden and energy consumption of the attitude control system.

[0044] Furthermore, the flow distributor is a smooth wedge-shaped structure. One end of the wedge-shaped structure is connected to the biomimetic body through its pivot, and the other end extends radially along the duct. The length of the wedge-shaped structure matches the end face diameter of the duct outlet, and the thickness of the wedge-shaped structure gradually decreases from the pivot to the radially extending end. The flow distributor's shaft is set perpendicular to the axis of the duct inlet, allowing the flow distributor to deflect vertically.

[0045] Specifically, the use of a wedge structure with a smooth surface and a gradually varying thickness significantly reduces the frictional resistance of water flowing over the distributor surface, reduces the total pressure loss introduced by the attitude control mechanism itself, and improves the overall hydraulic efficiency of the duct propulsion system. Secondly, the matching design of the radial length and the diameter of the duct end face ensures that the wedge structure can divide the tail of the duct into two independent and well-sealed jet outlets at any deflection angle, preventing water from leaking from the lateral gaps without control, and significantly improving the execution accuracy of flow distribution. At the same time, the arrangement of the rotating shaft perpendicular to the duct axis allows the wedge structure to achieve continuous deflection in the vertical direction with minimal rotational inertia, reducing energy consumption while improving the dynamic response speed of attitude adjustment.

[0046] Furthermore, the connecting end of the wedge-shaped structure shaft is embedded in the bionic body, the wedge-shaped structure is rotatably connected to the bionic body, and the connection between the wedge-shaped structure and the bionic body is sealed without affecting the rotation effect of the wedge-shaped structure, thereby forming a smooth duct surface at the connection between the wedge-shaped structure and the bionic body.

[0047] Specifically, this design allows the wedge structure to flexibly deflect within the duct to adjust flow distribution, while completely eliminating gaps at its connection with the main body. This effectively avoids momentum loss and control deviation caused by water leakage through the rotation gap, significantly improving the execution accuracy and energy utilization efficiency of flow distribution. The smooth and continuous duct wall eliminates interference caused by structural abrupt changes, keeping the flow field at the jet outlet stable and controllable, and improving the linearity between attitude control commands and response torque. Secondly, the sealed structure isolates the rotating mechanism from the external water flow, preventing silt intrusion and biological adhesion from causing wear and jamming of moving parts, thus improving the reliability of the system's long-term operation in complex underwater environments.

[0048] Furthermore, such as Figures 3-4 As shown, it also includes a drive mechanism, which is connected to the wedge structure and drives the wedge structure to rotate around its axis. Specifically, through precise angle control of the drive mechanism, the wedge structure can produce precise deflection, thereby accurately adjusting the flow area ratio of the two jet outlets. This transforms the abstract pitch torque requirement into a controllable difference in water flow rate exiting the jet outlets, significantly improving the accuracy and consistency of pitch attitude control for the biomimetic subject.

[0049] like Figure 5 As shown, the three working conditions are the velocity cloud diagrams of the bionic body when the wedge structure inside the body is symmetrical, shifted upward and downward. Through simulation results comparison, it is found that when the wedge structure is kept symmetrical and centered, the bionic body maintains a constant depth motion. Adjusting the vertical shift of the wedge structure can achieve autonomous control of the vertical motion of the bionic body.

[0050] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solution of the present invention, and are not intended to limit the specific implementation of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. A variable impulse method for attitude control of a manta ray-inspired aircraft by flow diversion within a duct, characterized in that, The manta ray-inspired vehicle includes: A biomimetic body, wherein the biomimetic body has a streamlined shape; A power duct module is axially disposed inside the bionic body, and the power duct module includes a through duct. A propeller is provided at the inlet end of the duct to propel the bionic body and generate axial water flow. A flow distributor is movably disposed at the center of the outlet end of the duct. The flow distributor is used to receive the axial water flow and split it to flow out of the bionic body through at least two independent jet outlets. By changing the position of the flow distributor in the duct, the velocity and momentum of the water jets ejected from each of the jet outlets are distributed and changed without changing the propeller speed, thereby generating an impulse between the jet outlets and a pitching moment perpendicular to the axis of the biomimetic body.

2. The variable impulse method according to claim 1, characterized in that, The power duct module includes an inlet duct and at least two outlet ducts that are interconnected. A propeller is provided at one end of the inlet duct, and the axis of the inlet duct coincides with or is parallel to the central axis of the biomimetic body. Each outlet duct is connected to a corresponding jet outlet. The inlet duct passes through the center of gravity of the biomimetic body, and the axes of the outlet ducts do not pass through the center of gravity of the biomimetic body.

3. The variable impulse method according to claim 2, characterized in that, The flow distributor is located at the connection between the inlet culvert and the outlet culvert. The ends of all the outlet culverts away from the jet outlet are simultaneously connected to the flow distributor. The flow distributor adjusts the flow area of ​​the outlet culverts to distribute and change the velocity and momentum of the water jetting from the corresponding jet outlet of each outlet culvert.

4. The variable impulse method according to claim 3, characterized in that, The manta ray-inspired vehicle also includes a drive mechanism, which is connected to the flow distributor and is used to drive and change the position of the flow distributor in the duct.

5. The variable impulse method according to claim 3, characterized in that, The biomimetic body has a flat, streamlined manta ray-like shape, including an axially arranged head, a tail, and symmetrically arranged side wings on both sides of the axial direction of the biomimetic body, and the upper surface of the tail of the biomimetic body is provided with tail wings.

6. The variable impulse method according to claim 5, characterized in that, The inlet duct smoothly transitions to the head of the bionic body, and the outlet duct faces the tail of the bionic body. Starting from the flow distributor, the axial diameter of the outlet duct gradually decreases towards the tail, and the outlet duct forms an angle of no more than 90° with the central axis of the bionic body.

7. The variable impulse method according to any one of claims 1-6, characterized in that, The bionic body is provided with two jet outlets symmetrically arranged based on the central axis of the bionic body, and the jet outlets are respectively located on the upper and lower surfaces of the bionic body.

8. The variable impulse method according to claim 7, characterized in that, The flow distributor is a smooth wedge-shaped structure. One end of the wedge-shaped structure is connected to the bionic body through its pivot, and the other end extends radially along the duct. The length of the wedge-shaped structure matches the end face diameter of the outlet end of the duct, and the thickness of the wedge-shaped structure gradually decreases from the pivot to the radially extending end. The flow distributor's rotating shaft is set perpendicular to the axis of the duct's inlet end, allowing the flow distributor to deflect vertically.

9. The variable impulse method according to claim 8, characterized in that, The connection end of the wedge structure and the rotating shaft is embedded in the bionic body. The wedge structure and the bionic body are rotatably connected, and the connection between the wedge structure and the bionic body is sealed without affecting the rotation effect of the wedge structure, thereby forming a smooth duct surface at the connection between the wedge structure and the bionic body.

10. The manta ray-inspired aircraft as described in any one of claims 1-9.

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