Bionic underwater vehicle based on self-sensing bending deformation and control method thereof

Abstract

The application relates to the technical field of underwater vehicles, in particular to a bionic underwater vehicle based on self-sensing bending deformation and a control method thereof, which comprises a fish body fixing plate, a root of a chest fin structure of a bionic manta ray is connected with the fish body fixing plate, a detection module is arranged in a silica gel skin, a driving structure is arranged on the fish body fixing plate and used for driving the chest fin structure to rotate around the length direction and driving the chest fin structure to flap in the up-down direction, and a control module is used for controlling the flapping parameters of the driving structure according to flow field information sensed by the detection module. The device acquires flow field information in the flapping process of the chest fin structure, so as to accurately control the movement of the vehicle.

Description

Technical Field

[0001] This invention relates to the field of underwater vehicle technology, specifically to a biomimetic underwater vehicle based on self-sensing bending deformation and its control method. Background Technology

[0002] Traditional propeller propulsion offers advantages such as easy installation, simple control, and convenient replacement and maintenance. However, its low efficiency, high noise, poor maneuverability, and susceptibility to malfunctions cannot be ignored. Meanwhile, underwater organisms have evolved various abilities to move in water over hundreds of millions of years. By mimicking the propulsion mechanisms of these organisms, it is possible to effectively improve the efficiency and maneuverability of underwater vehicles, as well as reduce noise and harm to marine life.

[0003] Most current biomimetic aircraft use rigid flapping wings, which cannot automatically achieve passive bending deformation of the flapping wings. In contrast, the flapping wings of real manta rays exhibit both active and passive deformation during flapping. Active deformation refers to the deformation of the pectoral fins caused by the manta ray overcoming fluid resistance, while passive deformation refers to the uncontrollable deformation that occurs in the water. As a result, the flapping movements of existing biomimetic aircraft are not similar to those of real organisms.

[0004] To date, existing technologies have proposed a wire-stayed structure adjustment method to achieve flapping fin bending deformation in biomimetic autonomous underwater vehicles. This method utilizes a tensioning structure to achieve passive bending deformation of the flapping fins during upward and downward flapping. However, the tensioning structures of large vehicles often employ alloys and multiple sets of wire-stayed wheel assemblies, significantly increasing the load on the motor. Furthermore, the wire-stayed wheel assemblies are exposed to seawater for extended periods, and oxidation or pressure deformation can affect the vehicle's maneuverability. Large biomimetic underwater vehicles are generally used for deep-sea scientific research and exploration. However, current calculations of underwater pressure and pectoral fin deformation at operating depth rely heavily on simulations. But underwater ocean currents are complex and variable; simulations can only provide theoretical data and cannot collect real-time data on pressure values, pectoral fin deformation, and flow field conditions at the operating depth. Conducting experiments in variable and unmonitorable ocean current environments can lead to irreparable damage to the vehicle due to sudden changes in the flow field.

[0005] Therefore, there is a need to provide a biomimetic underwater vehicle based on self-sensing bending deformation and its control method to solve the above problems. Summary of the Invention

[0006] This invention provides a biomimetic underwater vehicle and its control method based on self-sensing bending deformation. It utilizes the fin-ray effect, the phenomenon in nature where fish fins deform in the opposite direction of force. When flapping upwards, the fish's pectoral fins bend towards the head near the apex of the upward flap; when flapping downwards, they bend near the lowest point of the downward flap. Then, combined with fiber optic sensors, the pressure energy of the fluid acting on the pectoral fins is converted into electrical energy to acquire information on the pressure distribution of the flow field on the pectoral fin surface, the vortex system in the water flow field, and the degree of bending deformation of the pectoral fins. Combined with the manta ray-inspired underwater vehicle's own navigation attitude, this effectively improves the underwater vehicle's ability to perceive and judge the surrounding flow field information and its own motion mode. This solves the problem of existing multi-set pulley systems, which greatly increase the load on the motor, and the fact that long-term exposure of the pulley systems to seawater can lead to oxidation or pressure deformation, affecting the vehicle's maneuverability.

[0007] The present invention provides a biomimetic underwater vehicle based on self-sensing bending deformation, which adopts the following technical solution: including: Fish body fixing plate; The biomimetic manta ray pectoral fin structure is connected at its base to a fish body fixing plate, and includes a flexible support frame and a silicone skin; the tip of the flexible support frame is hinged to a tip fin plate, and the silicone skin is applied to the surface of the flexible support frame and the tip fin plate. The detection module, located inside the silicone skin, is used to sense the flow field information of the pectoral fin structure in the water; The drive structure, which is set on the fish body fixing plate, is used to drive the pectoral fin structure to rotate around its length and to drive the pectoral fin structure to flap in its vertical direction.

[0008] And a control module, used to control the flapping parameters of the drive structure to adjust the motion state of the vehicle based on the flow field information sensed by the detection module.

[0009] Preferably, the flexible support frame includes: Multiple fin plates are spaced apart along the length of the pectoral fin structure, and the size of the multiple fin plates is proportionally reduced from the root to the tip of the pectoral fin structure. The structure of the fin plates is an elliptical plate. Two fin support plates are set on both sides of the fin and are rotatably connected to the outer arc surface of the fin. And two end support ribs are provided between the ends of the two fin support plates, and their ends are hinged to the ends of the fin support plates. The end support ribs on the side closer to the fish body fixing plate are connected to the fish body fixing plate through the fin support plate.

[0010] Preferably, the two fin support plates and the two end support ribs are connected to form a trapezoidal structure, wherein the bottom surface of the trapezoidal structure faces the fish body fixing plate.

[0011] Preferably, a groove is formed on the outer arc surface of the fin, the fin support plate is installed in the groove, and the end face of the fin support plate is rotatably connected to the corresponding groove wall.

[0012] Preferably, the drive structure includes: a first drive component and a second drive component; The first drive assembly is mounted on the fish body fixing plate, and its output end is connected to the motor fixing plate for driving the motor fixing plate to rotate. The second drive component includes a flapping motor, which is mounted on a motor mounting plate. Its output end is connected to a drive shaft perpendicular to its output end. The drive shaft passes through a mounting hole opened on the fin plate on one side of the root of the pectoral fin structure, and the drive shaft can slide within the mounting hole.

[0013] Preferably, the first drive component includes: A torsion motor, which is fixed to the fish body fixing plate by a torsion motor support frame; And a rotating shaft, which is mounted on the fish body fixing plate by a rotating shaft support frame and is perpendicular to the output shaft of the torsion motor. The rotating shaft and the torsion motor are connected by gear transmission, and the end of the rotating shaft passes through the rotating shaft support frame and is connected to the motor fixing plate.

[0014] Preferably, the detection module includes multiple fiber optic sensors, which are evenly distributed on the outer surface of the silicone skin of the pectoral fin structure.

[0015] Preferably, the flapping parameters include the frequency, amplitude, and phase of the flapping motor.

[0016] Preferably, the flow field information includes pressure and water flow disturbance.

[0017] A control method for a biomimetic underwater vehicle based on self-sensing bending deformation involves controlling the flapping motor of the vehicle to increase frequency, decrease amplitude, and decrease phase when the pressure on the pectoral fin structure is detected to be continuously decreasing, until the pressure stops decreasing; when the pressure on the pectoral fin structure is detected to be continuously increasing, the flapping motor of the vehicle is controlled to decrease frequency, increase amplitude, and increase phase, until the pressure stops changing; when the water flow disturbance on the pectoral fin structure is detected to be increasing, the flapping motor is controlled to increase frequency, decrease amplitude, and decrease phase, until the water flow disturbance stops changing.

[0018] The beneficial effects of this invention are: By setting up a pectoral fin structure, which includes a flexible support frame and a silicone skin, and hinged fin plates at the tips of the flexible support frame, the silicone skin is applied to the surfaces of the flexible support frame and the fin plates. Then, a drive structure drives the pectoral fin structure to rotate around its length and flap vertically, simulating the phenomenon in nature where fish fins deform in the opposite direction of force. When flapping upwards, the fish's pectoral fin bends towards its head near the apex of the flap; when flapping downwards, it bends near the lowest point of the flap. This allows the detection module to accurately detect the flow field information of the pectoral fin structure in the water, reflecting the force and water flow disturbance on the pectoral fin structure in real time. This allows for precise determination of whether the vehicle is surfacing, diving, or in a course with significant water flow disturbance. Based on this, the motor parameters of the flapping motor are precisely controlled, enabling precise adjustment of the vehicle's navigation status. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the biomimetic underwater vehicle based on self-sensing bending deformation according to the present invention; Figure 2 This is a top view of a biomimetic underwater vehicle based on self-sensing bending deformation according to the present invention; Figure 3 This is a front view of a biomimetic underwater vehicle based on self-sensing bending deformation according to the present invention. Figure 4 This is a force diagram of a flexible support frame for a biomimetic underwater vehicle based on self-sensing bending deformation according to the present invention. Figure 5 This is a schematic diagram of the drive structure and fish-body fixing plate in a biomimetic underwater vehicle based on self-sensing bending deformation according to the present invention. Figure 6 This is a schematic diagram of the structure of a silicone skin and fiber optic sensor in a biomimetic underwater vehicle based on self-sensing bending deformation according to the present invention. In the diagram: 1. Fish body fixing plate; 2. Torsion motor; 3. Rotary shaft support frame; 4. Fluttering motor; 5. Motor fixing plate; 6. Upright plate; 7. Drive shaft; 8. First fin plate; 9. Second fin plate; 10. Third fin plate; 11. Fourth fin plate; 12. Tip fin plate; 13. Tip support rib plate; 14. Fin plate support plate; 15. Fiber optic sensor; 16. Silicone skin. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] This invention provides a biomimetic underwater vehicle based on self-sensing bending deformation, such as... Figure 1 As shown, the system includes: a fish-body fixing plate 1, a biomimetic manta ray pectoral fin structure, a detection module, a drive structure, and a control module. The root of the biomimetic manta ray pectoral fin structure is connected to the fish-body fixing plate 1. Specifically, the biomimetic manta ray pectoral fin structure includes a flexible support frame and a silicone skin 16. A tip fin plate 12 is hinged to the tip of the flexible support frame. The silicone skin 16 covers the surfaces of the flexible support frame 13 and the tip fin plate 12, thus forming the entire pectoral fin. In this embodiment, the pectoral fin adopts the flapping shape of the NACA00 series airfoil. The detection module is located outside the silicone skin 16 to sense the flow field information of the pectoral fin structure in the water. The drive structure is located on the fish-body fixing plate 1 and is used to drive the pectoral fin structure to rotate around its length and flap vertically. The control module is used to control the flapping parameters of the drive structure based on the flow field information sensed by the detection module to adjust the motion state of the vehicle.

[0023] The flexible support frame 13 includes: multiple fins, two fin support plates 14, and two end support ribs. Specifically, this embodiment includes four fins, which are equidistantly spaced along the length of the pectoral fin structure, and the dimensions of the four fins are proportionally reduced from the root to the tip of the pectoral fin structure. The fins are quasi-elliptical in shape. Specifically, as shown... Figure 1 and Figure 2As shown, the four fin plates along the length of the pectoral fin structure are, in sequence, the first fin plate 8, the second fin plate 9, the third fin plate 10, and the fourth fin plate 11; two fin plate support plates 14 are disposed on both sides of the fin plates, and the fin plate support plates 14 are rotatably connected to the outer arc surface of each fin plate; two end support ribs are disposed between the ends of the two fin plate support plates 14, and their ends are hinged to the ends of the fin plate support plates 14, wherein the end support ribs on the side closer to the fish body fixing plate 1 are connected to the fish body fixing plate 1 through the fin plate support plates 14.

[0024] The two fin support plates and two end support ribs are connected to form a trapezoidal structure, with the bottom surface of the trapezoidal structure facing the fish body fixing plate 1. The outer arc surface of the fin plate has a groove, and the fin support plate is installed in the groove. The end face of the fin support plate and the corresponding groove wall are rotatably connected. The two fin support plates are used to adjust the orderly movement of the fin plate and to maintain its shape.

[0025] Specifically, the drive structure includes: a first drive assembly and a second drive assembly; the first drive assembly is mounted on the fish body fixing plate 1, and its output end is connected to a motor fixing plate 5 for driving the motor fixing plate 5 to rotate; the second drive assembly is mounted on the motor fixing plate 5, and the second drive assembly adopts a flapping motor 4. The output end of the flapping motor 4 is connected to a transmission shaft 7 perpendicular to its output end. The transmission shaft 7 passes through a mounting hole opened on the fin plate on one side of the root of the pectoral fin structure, and the transmission shaft 7 can slide within the mounting hole.

[0026] Specifically, the first drive component includes a torsion motor 2 and a rotating shaft 17. The torsion motor 2 is fixed on the fish body fixing plate 1 by a torsion motor support frame. The rotating shaft 17 is mounted on the fish body fixing plate 1 by a rotating shaft support frame 3, and the rotating shaft 17 is perpendicular to the output shaft of the torsion motor 2. The rotating shaft 17 is connected to the torsion motor 2 by gear transmission, and the end of the rotating shaft 17 passes through the rotating shaft support frame 3 and is connected to the motor fixing plate 5.

[0027] Specifically, the detection module includes multiple fiber optic sensors 15, which are evenly distributed on the outer surface of the silicone skin 16 of the pectoral fin structure. Through the ultra-high precision piezoelectric characteristics of the fiber optic sensors 13, the pressure energy of the fluid can be converted into electrical energy, realizing high-sensitivity and rapid underwater monitoring at the millipascal level, and obtaining the flow field pressure distribution on the surface of the pectoral fin structure, the vortex system of the water flow field, and the degree of bending deformation of the pectoral fin structure.

[0028] Specifically, the flapping parameters include the frequency, amplitude, and phase of the flapping motor 4. Specifically, since the flapping motor 4 has a built-in electronic control unit, the frequency, amplitude, and phase are programmed according to logic and definition in the electronic control system. The frequency is the speed of flapping, the amplitude is the amplitude of the up-and-down flapping of the pectoral fin structure, and the phase is the waveform change of the chordal flapping of the pectoral fin structure.

[0029] The present invention also discloses a control method for a biomimetic underwater vehicle based on self-sensing bending deformation. When the pressure on the pectoral fin structure is detected to be decreasing, the flapping motor 4 of the vehicle is controlled to increase the frequency, decrease the amplitude, and decrease the phase until the pressure no longer decreases. When the pressure on the pectoral fin structure is detected to be increasing, the flapping motor 4 of the vehicle is controlled to decrease the frequency, increase the amplitude, and increase the phase until the pressure no longer changes. When the water flow disturbance on the pectoral fin structure is detected to be increasing, the flapping motor 4 is controlled to increase the frequency, decrease the amplitude, and decrease the phase until the water flow disturbance no longer changes. Specifically, when the vehicle is operating underwater, the flapping frequency, amplitude, and phase of the flapping motor 4 are adjusted in real time through an external control system. Frequency refers to the speed of flapping, amplitude to the vertical flapping amplitude of the pectoral fin structure, and phase to the waveform change of the chordal flapping of the pectoral fin structure. These are collectively referred to as the motion parameters of the pectoral fin structure of the biomimetic underwater vehicle. The coupling of these three parameters enables motion control of the entire biomimetic underwater vehicle. Based on existing large-scale vehicle experiments, underwater vehicles with low-frequency, large-amplitude, and high-phase flapping exhibit better hydrodynamic performance, making it easier to generate thrust and relatively small lift in the forward direction. As the biomimetic vehicle's operating depth increases, the water pressure applied to the biomimetic pectoral fin structure gradually increases, suppressing the vehicle's hydrodynamic performance. The fiber optic sensor 15 on the silicone skin 16 converts the fluid pressure energy into electrical energy and transmits it back to the control system. After receiving the pressure data feedback, the control system controls the electronic control unit of the flapping motor 4 to reduce its frequency and increase its amplitude. The system achieves deep-sea swimming by increasing amplitude and phase, while simultaneously adjusting the buoyancy system to achieve diving. During the buoyancy adjustment process, as the pressure on the pectoral fin structure decreases, the lift generated by the motion parameters at great depths is insufficient to make the bionic vehicle float. At this point, the fiber optic sensor 15 on the silicone skin 16 converts the pressure energy of the fluid into electrical energy and transmits it back to the control system. After receiving the pressure data feedback, the control system controls the electronic control unit of the flapping motor 4 to increase the frequency, decrease the amplitude, and decrease the phase, and adjusts the vehicle's buoyancy by combining this with the motion of the buoyancy system's center of mass mechanism. In sea areas with large environmental current disturbances, the pressure monitoring by the fiber optic sensor 15 can control the electronic control unit of the flapping motor 4 to increase the frequency, decrease the amplitude, and decrease the phase, thereby reducing the forward thrust. Combined with the vehicle's own pump-jet system, the vehicle can move away from the sea area. The fiber optic sensor 15 can achieve high-sensitivity, real-time, and rapid underwater monitoring at the millipascal level, effectively improving the vehicle's ability to perceive and judge the surrounding flow field information and its own motion modes.

[0030] It should be noted that the torsion motor 2 drives the pectoral fin structure to rotate, and the flapping motor 4 drives the pectoral fin structure to flap. That is, the movement of the pectoral fin structure generates spanwise and chordal waves. The coupling of the spanwise and chordal waves makes the movement of fish, which uses the median and paired fin locomotion (MPF) propulsion mode of the vehicle of this invention, more similar to that of fish, so as to conform to the movement law of real organisms. At the same time, during the movement of the pectoral fin structure, the silicone skin 16 on the pectoral fin structure is compressed. The fiber optic sensor 15 on the silicone skin 16 converts the pressure energy of the fluid into electrical energy, realizing high-sensitivity and rapid underwater millipascal-level monitoring. This mainly helps the biomimetic underwater vehicle to obtain information such as the pressure distribution of the flow field on the pectoral fin surface, the vortex system of the flow field in the water, and the degree of bending deformation of the pectoral fin when moving in the water. Combined with the navigation attitude of the biomimetic underwater vehicle, the vehicle's ability to perceive and judge the surrounding flow field information and its own motion mode is effectively improved.

[0031] like Figure 4 As shown, Figure 4 When rotated 90° clockwise, the result is... Figure 4 The first image represents the pectoral fin structure in its normal state, and the second image represents the pectoral fin structure under force, or in other words, the manta ray slapping upwards in a water flow environment. F represents the downward resistance generated by the water flow. After being subjected to the downward resistance of the water flow, the pectoral fin structure will bend upwards. This is consistent with the fin-ray effect, which describes the phenomenon in nature where fish fins deform in the opposite direction of the force. When slapping upwards, the fish's pectoral fin bends towards the top of the head near the top of the slap; when slapping downwards, the fish's pectoral fin bends near the bottom of the slap. Therefore, this structure is also designed based on this principle.

[0032] In summary, the present invention provides a biomimetic underwater vehicle based on self-sensing bending deformation. This is achieved by incorporating a pectoral fin structure, comprising a flexible support frame and a silicone skin. A tip fin plate is hinged to the end of the flexible support frame, and the silicone skin covers the surfaces of the flexible support frame and the tip fin plate. Then, a driving structure drives the pectoral fin structure to rotate around its length and to flap vertically, thereby simulating the phenomenon in nature where fish fins deform in the opposite direction of force when subjected to stress. When the fish flaps its pectoral fins upwards, they bend towards the top of its head near the apex of the flap; when it flaps downwards, they bend near the lowest point of the flap. This allows the detection module to accurately detect the flow field information of the pectoral fin structure in the water. By using the flow field information, the module can reflect the forces and water flow disturbances on the pectoral fin structure in the water in real time, and thus accurately determine whether the vehicle is surfacing, diving, or in a course with large water flow disturbances. Based on the navigation status, the module can precisely control the motor parameters of the flapping motor to achieve precise adjustment of the vehicle's navigation status.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A biomimetic underwater vehicle based on self-sensing bending deformation, characterized in that, include: Fish body fixing plate (1); The pectoral fin structure of the biomimetic manta ray is connected at its base to the fish body fixing plate (1), which includes a flexible support frame and a silicone skin (16); the tip of the flexible support frame is hinged with a tip fin plate (12), and the silicone skin (16) is covered on the surface of the flexible support frame and the tip fin plate (12). The detection module is set outside the silicone skin (16) and is used to sense the flow field information of the pectoral fin structure in the water. The flow field information includes pressure and water flow disturbance. A drive structure is set on the fish body fixing plate (1) for driving the pectoral fin structure to rotate around its length direction and driving the pectoral fin structure to flap in its vertical direction; the drive structure includes: a first drive assembly and a second drive assembly; the first drive assembly is installed on the fish body fixing plate (1), and its output end is connected to a motor fixing plate (5) for driving the motor fixing plate (5) to rotate; the second drive assembly includes a flapping motor (4), the flapping motor (4) is installed on the motor fixing plate (5), and its output end is connected to a transmission shaft (7) perpendicular to its output end, the transmission shaft (7) passes through the mounting hole opened on the fin plate on one side of the root of the pectoral fin structure, and the transmission shaft (7) can slide in the mounting hole; And a control module, used to control the flapping parameters of the drive structure to adjust the motion state of the vehicle based on the flow field information sensed by the detection module; when the pressure on the pectoral fin structure is detected to be decreasing, the flapping motor (4) of the vehicle is controlled to increase the frequency, decrease the amplitude and decrease the phase until the pressure no longer decreases; when the pressure on the pectoral fin structure is detected to be increasing, the flapping motor (4) of the vehicle is controlled to decrease the frequency, increase the amplitude and increase the phase until the pressure no longer changes; when the water flow disturbance on the pectoral fin structure is detected to be increasing, the flapping motor (4) is controlled to increase the frequency, decrease the amplitude and decrease the phase until the water flow disturbance no longer changes.

2. The biomimetic underwater vehicle based on self-sensing bending deformation according to claim 1, characterized in that, The flexible support frame (13) includes: Multiple fin plates are spaced apart along the length of the pectoral fin structure, and the size of the multiple fin plates is proportionally reduced from the root to the tip of the pectoral fin structure. The structure of the fin plates is an elliptical plate. Two fin support plates (14) are provided on both sides of the fin and are rotatably connected to the outer arc surface of the fin; And two end support ribs are provided between the ends of the two fin support plates (14), and their ends are hinged to the ends of the fin support plates (14). The end support ribs on the side closer to the fish body fixing plate (1) are connected to the fish body fixing plate (1) through the fin support plates (14).

3. A biomimetic underwater vehicle based on self-sensing bending deformation according to claim 2, characterized in that, The two end support ribs have different lengths, and the two fin support plates and the two end support ribs are connected to form a trapezoidal structure, wherein the bottom surface of the trapezoidal structure faces the fish body fixing plate (1).

4. A biomimetic underwater vehicle based on self-sensing bending deformation according to claim 2, characterized in that, A groove is formed on the outer arc surface of the fin, and the fin support plate is installed in the groove, with the end face of the fin support plate and the corresponding groove wall being rotatably connected.

5. A biomimetic underwater vehicle based on self-sensing bending deformation according to claim 1, characterized in that, The first driving component includes: Torsion motor (2), which is fixed to the fish body fixing plate (1) by a torsion motor support frame; And a rotating shaft (17) is mounted on the fish body fixing plate (1) via a rotating shaft support frame (3) and is perpendicular to the output shaft of the torsion motor (2). The rotating shaft (17) is connected to the torsion motor (2) via gear transmission, and the end of the rotating shaft (17) passes through the rotating shaft support frame (3) and is connected to the motor fixing plate (5).

6. A biomimetic underwater vehicle based on self-sensing bending deformation according to claim 1, characterized in that, The detection module includes multiple fiber optic sensors (15), which are evenly distributed on the outer surface of the silicone skin (16) of the pectoral fin structure.

7. A biomimetic underwater vehicle based on self-sensing bending deformation according to claim 1, characterized in that, The flapping parameters include the frequency, amplitude, and phase of the flapping motor (4).

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