Underwater navigation device with biomimetic swim bladder and motion control algorithm

Abstract

The application discloses an underwater navigation device with a bionic swim bladder and a motion control algorithm. The underwater navigation device with the bionic swim bladder comprises a shell, a first flexible film, a second flexible film, a push-pull rod driving mechanism and a tail fin propelling mechanism. The shell comprises a head, a tail and a main body connecting the head and the tail. The first flexible film is arranged between the head and the main body. The second flexible film covers a gap of the main body. The first flexible film, the main body and the second flexible film surround to form a swim bladder chamber. The volume change of the swim bladder chamber caused by deformation of the first flexible film is greater than the volume change of the swim bladder chamber caused by deformation of the second flexible film. The push-pull rod driving mechanism is used for driving the first flexible film to deform. The tail fin propelling mechanism is arranged at the tail. The tail fin driving mechanism is arranged in the shell and is used for driving the bionic tail fin to swing. The technical scheme provided by the application can solve the technical problems of long response time of buoyancy adjustment and high energy consumption of the underwater navigation device with the bionic swim bladder.

Description

Technical Field

[0001] The present invention relates to the field of robotics, and in particular to an underwater navigation device with a bionic fish swim bladder and a motion control algorithm. Background Art

[0002] Underwater navigation devices are devices that can navigate underwater autonomously or remotely to perform specific tasks. They are widely used in various fields, including military, marine science, and underwater engineering. However, underwater navigation devices generally suffer from technical issues such as long response time and high energy consumption to achieve buoyancy regulation.

[0003] Therefore, it is necessary to provide a new underwater navigation device with a bionic fish swim bladder and a motion control algorithm to solve the above technical problems. Summary of the Invention

[0004] The main purpose of the present invention is to provide an underwater navigation device with a bionic fish swim bladder and a motion control algorithm, aiming to solve the technical problems of long response time and high energy consumption existing in underwater navigation devices.

[0005] To achieve the above objectives, the present invention proposes an underwater navigation device with a bionic fish swim bladder, comprising a housing, a first flexible membrane, a second flexible membrane, a push-pull rod drive mechanism, and a tail fin propulsion mechanism. The housing includes a head, a tail, and a body connecting the head and tail. The first flexible membrane is disposed between the head and the body. The body is provided with a notch, and the second flexible membrane covers the notch. The first flexible membrane, the body, and the second flexible membrane enclose a swim bladder chamber. The following definition is provided: deformation of the first flexible membrane causes a volume change of ΔV1, and deformation of the second flexible membrane causes a volume change of ΔV2. Therefore, |ΔV1|>|ΔV2|.

[0006] The push-pull rod driving mechanism is arranged in the swim bladder chamber and is used to drive the deformation of the first flexible membrane. The tail fin propulsion mechanism includes a bionic tail fin and a tail fin driving mechanism. The bionic tail fin is rotatably arranged on the tail; the tail fin driving mechanism is arranged in the shell and is used to drive the bionic tail fin to swing.

[0007] In one embodiment, the push-pull rod driving mechanism includes a fixed seat, a driving member and a pushing block, the driving member and the pushing block are both arranged on the fixed seat, the pushing block is connected to the output end of the driving member and abuts against the first flexible membrane; the driving member is used to drive the pushing block to move toward or away from the head to drive the first flexible membrane to deform.

[0008] In an embodiment, the pushing block is spaced apart from the driving member on the fixed seat, the pushing block comprises a coaxially arranged inner rod and an outer tube, the inner rod is rotationally arranged on the fixed seat, and the inner rod is arranged through the outer tube and is threadedly connected with the outer tube; the driving member is used to drive the inner rod to rotate, thereby driving the outer tube to move towards or away from the head.

[0009] In an embodiment, the pushing block is provided with a push head, the push head is provided with an arc surface abutting against the first flexible film.

[0010] In an embodiment, the first flexible film and the second flexible film are both embedded with flexible sensors; and the elasticity of the first flexible film is greater than the elasticity of the second flexible film; and / or, the area of the first flexible film is greater than the area of the second flexible film; and / or, the thickness of the first flexible film is less than the thickness of the second flexible film.

[0011] In an embodiment, the tail fin driving mechanism comprises a driving unit connected in sequence, and a shaft rod, a connecting rod and a swing arm hingedly connected in sequence, the bionic tail fin is rotationally arranged on the tail through a rotating shaft, the shaft rod is connected with the output end of the driving unit, the swing arm is hingedly connected with the rotating shaft, and the swing arm is arranged at an angle with the rotating shaft, and the connecting rod is arranged at an angle with the shaft rod and the swing arm.

[0012] In an embodiment, the underwater navigation device with bionic swim bladder further comprises a pectoral fin flapping mechanism, the pectoral fin flapping mechanism comprises a bionic pectoral fin and a pectoral fin driving mechanism, the pectoral fin driving mechanism is arranged in the shell, the bionic pectoral fin is rotationally arranged on the pectoral fin driving mechanism and extends out of the main body; the pectoral fin driving mechanism is used to drive the bionic pectoral fin to swing around its rotation axis, and is used to drive the bionic pectoral fin to rotate towards or away from the head at one end away from the main body.

[0013] In an embodiment, the pectoral fin driving mechanism comprises a bracket, a first steering gear, a second steering gear and a transmission member arranged on the bracket, the bionic pectoral fin is rotationally arranged on the transmission member; the first steering gear drives the bionic pectoral fin to rotate around the vertical direction of the transmission member through the transmission member, so that the bionic pectoral fin rotates towards or away from the head at one end away from the main body, and the second steering gear drives the bionic pectoral fin to swing around its rotation axis through the transmission member.

[0014] In one embodiment, the transmission member includes a housing and a helical gear disposed within the housing, one end of the bionic pectoral fin is disposed within the housing and meshes with the helical gear, and the bracket is further provided with a first synchronous wheel, a second synchronous wheel, and a first shaft and a second shaft coaxially nested, the first shaft connecting the first synchronous wheel and the housing, and the second shaft connecting the helical gear;

[0015] The first servo drives the first shaft to rotate through the first synchronous belt and the first synchronous wheel, thereby driving the shell to rotate around the vertical direction of the transmission member to drive the bionic pectoral fin to rotate around the vertical direction of the transmission member; the second servo drives the second shaft to rotate through the second synchronous belt and the second synchronous wheel, thereby driving the bevel gear to rotate to drive the bionic pectoral fin to swing around its rotation axis.

[0016] In one embodiment, the underwater navigation device with the bionic swim bladder is further provided with a sensor group, which includes a visual sensor, a depth sensor and an inertial sensor.

[0017] In addition, the present invention also provides a motion control method, which is applied to the underwater navigation device with a bionic swim bladder as described above, and the motion control method includes:

[0018] Acquiring current speed information, current heading information, and current pitch attitude information of the underwater navigation device having a bionic fish swim bladder;

[0019] Comparing the preset speed information with the current speed information, and controlling the tail fin drive mechanism by the bionic tail fin controller according to an error value between the preset speed information and the current speed information, thereby adjusting the swimming speed of the underwater sailing device with the bionic fish swim bladder so that the underwater sailing device with the bionic fish swim bladder reaches the preset swimming speed;

[0020] Comparing the preset heading information with the current heading information, and controlling the pectoral fin drive mechanism by the bionic pectoral fin controller according to an error value between the preset heading information and the current heading information, thereby adjusting the heading angle of the underwater sailing device with the bionic fish swim bladder so that the underwater sailing device with the bionic fish swim bladder reaches the preset heading angle;

[0021] The preset pitch attitude information and the current pitch attitude information are compared. According to the error value between the preset pitch attitude signal and the current pitch attitude information, the bionic fish maw controller controls the operation of the push-pull rod drive mechanism to adjust the pitch attitude and depth of the underwater navigation device with the bionic fish maw so that the underwater navigation device with the bionic fish maw reaches the preset pitch attitude and depth.

[0022] The technical solution of the present invention achieves rapid adjustment of the buoyancy of an underwater vehicle by providing a first flexible membrane and a second flexible membrane that form a swim bladder chamber with the main body. A push-pull rod drive mechanism drives the deformation of the first flexible membrane, thereby reducing the energy consumption of the underwater vehicle. Furthermore, the second flexible membrane adjusts the volume of the swim bladder chamber using water pressure or gas pressure within the swim bladder chamber, thereby reducing the energy consumption of the underwater vehicle. In this embodiment, the first flexible membrane is disposed between the head and the main body, and the second flexible membrane is disposed on the peripheral wall of the main body. The first flexible membrane, the second flexible membrane, and the main body form the swim bladder chamber. The push-pull rod drive mechanism is disposed within the housing and is used to drive the deformation of the first flexible membrane. Directly driving the deformation of the first flexible membrane by the push-pull rod drive mechanism allows for more rapid changes in the volume of the underwater vehicle and adjustment of its buoyancy. This eliminates the need for gas compression and transmission, thereby improving the response speed of the underwater vehicle during buoyancy adjustment. The second flexible membrane, installed in the main body, can reduce the underwater vehicle's energy consumption. Specifically, the second flexible membrane relies solely on water pressure or gas pressure within the swim bladder chamber to adjust the volume of the swim bladder chamber, thereby changing the volume of the underwater vehicle. This eliminates the need for additional energy to drive the membrane, thus reducing the underwater vehicle's energy consumption. Furthermore, when the push-pull rod drive mechanism drives the first flexible membrane to deform, thereby adjusting the buoyancy of the underwater vehicle, the second flexible membrane passively compensates for changes in the buoyancy of the underwater vehicle's head, thereby preventing the underwater vehicle from losing weight and ensuring the stability of the underwater vehicle during buoyancy adjustment. The volume change of the swim bladder chamber caused by deformation of the first flexible membrane is greater than the volume change caused by deformation of the second flexible membrane. This is intended to ensure that the push-pull rod drive mechanism can change the volume of the underwater navigation device when driving the first flexible membrane to deform. Specifically, when the push-pull rod drive mechanism drives the first flexible membrane to bulge toward the head, the first flexible membrane will squeeze the water within the head, and the second flexible membrane will recess inward under the action of water pressure. Because the volume change of the swim bladder chamber caused by deformation of the first flexible membrane is greater than the volume change caused by deformation of the second flexible membrane, the volume of the underwater navigation device gradually increases when the push-pull rod drive mechanism drives the first flexible membrane to deform, facilitating volume expansion and buoyancy during ascent, thereby reducing ascent energy consumption. Conversely, the volume of the underwater navigation device gradually decreases when the push-pull rod drives the first flexible membrane to deform, facilitating volume contraction and buoyancy during descent, thereby reducing descent energy consumption. The tail fin propulsion mechanism is used to provide propulsion for the underwater navigation device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0024] Figure 1 Structure diagram of underwater navigation device with bionic swim bladder in an embodiment provided by the present application;

[0025] Figure 2 Structure diagram of push-pull rod driving mechanism in an embodiment provided by the present application;

[0026] Figure 3 Structure diagram of underwater navigation device with bionic swim bladder without push-pull rod driving mechanism in an embodiment provided by the present application;

[0027] Figure 4 Structure diagram of chest fin flapping mechanism in an embodiment provided by the present application;

[0028] Figure 5 Flow diagram of motion control method in an embodiment provided by the present application.

[0029] Explanation of reference numerals:

[0030] 100, shell; 110, head; 120, tail; 130, main body; 131, swim bladder chamber; 200, first flexible film; 300, second flexible film; 400, push-pull rod driving mechanism; 410, fixing seat; 411, sleeve; 420, driving piece; 430, pushing block; 431, inner rod; 432, outer tube; 433, pushing head; 4331, arc surface; 500, tail fin propelling mechanism; 510, bionic tail fin; 520, tail fin driving mechanism; 521, driving unit; 522, shaft rod; 523, connecting rod; 524, swing arm; 600, chest fin flapping mechanism; 610, bionic chest fin; 620, chest fin driving mechanism; 621, support; 6211, first synchronous wheel; 6212, second synchronous wheel; 622, first steering engine; 623, second steering engine; 624, transmission piece; 6241, housing; 6242, helical gear.

[0031] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0033] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0034] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features specified as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that meet both A and B.

[0035] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0036] An underwater navigation device is a device that can navigate underwater autonomously or remotely and perform specific tasks. It is widely used in many fields, including military, marine science, and underwater engineering. During actual production and research and development, researchers have found that most underwater navigation devices adjust their buoyancy based on aerodynamic principles. That is, by changing the volume of gas inside the underwater navigation device, the buoyancy of the underwater navigation device is changed, thereby achieving ascent and descent. It mainly uses an air pump or similar device to compress and transmit gas to change the volume of gas inside the underwater navigation device to achieve buoyancy adjustment. However, when using the above method to adjust the buoyancy of the underwater navigation device, the compression and transmission speed of the gas is slow, which will reduce the response speed of the underwater navigation device when adjusting its buoyancy. At the same time, the compression and transmission of the gas require energy, which will increase the energy consumption of the underwater navigation device when adjusting its buoyancy.

[0037] The present invention proposes an underwater navigation device with a bionic fish swim bladder and a motion control algorithm, aiming to solve the technical problems of long response time and high energy consumption existing in underwater navigation devices.

[0038] See also Figure 1In an embodiment of the present application, the underwater navigation device with bionic swim bladder comprises a shell 100, a first flexible film 200, a second flexible film 300, a push-pull rod driving mechanism 400 and a tail fin propelling mechanism 500. The shell 100 comprises a head 110, a tail 120 and a main body 130 connecting the head 110 and the tail 120. The first flexible film 200 is arranged between the head 110 and the main body 130. The main body 130 is provided with a gap. The second flexible film 300 covers the gap. The first flexible film 200, the main body 130 and the second flexible film 300 surround to form a bladder chamber 131. Definition: the volume change of the bladder chamber 131 caused by the deformation of the first flexible film 200 is ΔV1, and the volume change of the bladder chamber 131 caused by the deformation of the second flexible film 300 is ΔV2. Then, |ΔV1|>|ΔV2| is obtained. The push-pull rod driving mechanism 400 is arranged in the bladder chamber 131 and is used to drive the deformation of the first flexible film 200. The tail fin propelling mechanism 500 comprises a bionic tail fin 510 and a tail fin driving mechanism 520. The bionic tail fin 510 is rotatably arranged in the tail 120. The tail fin driving mechanism 520 is arranged in the shell 100 and is used to drive the bionic tail fin 510 to swing.

[0039] The technical solution of the present invention achieves rapid adjustment of the buoyancy of an underwater navigation device by disposing a first flexible membrane 200 and a second flexible membrane 300 that enclose the main body 130 to form a swim bladder chamber 131. The push-pull rod drive mechanism 400 drives the deformation of the first flexible membrane 200. Furthermore, the second flexible membrane 300 regulates the volume of the swim bladder chamber 131 through water pressure or gas pressure within the swim bladder chamber 131, thereby reducing the energy consumption of the underwater navigation device. In this embodiment, the first flexible membrane 200 is disposed between the head 110 and the main body 130, and the second flexible membrane 300 is disposed on the peripheral wall of the main body 130. The first flexible membrane 200, the second flexible membrane 300, and the main body 130 enclose the swim bladder chamber 131. The push-pull rod drive mechanism 400 is disposed within the housing 100 and is used to drive the deformation of the first flexible membrane 200. By directly driving the deformation of the first flexible membrane 200 through the push-pull rod drive mechanism 400, the volume of the underwater vehicle can be changed more quickly, adjusting the buoyancy of the underwater vehicle. This eliminates the need for compressed and transmitted gas, thereby improving the response speed of the underwater vehicle during buoyancy adjustment. The second flexible membrane 300, disposed within the main body 130, reduces the energy consumption of the underwater vehicle. Specifically, the second flexible membrane 300 adjusts the volume of the swim bladder chamber 131 solely by water pressure or gas pressure within the swim bladder chamber 131, thereby changing the volume of the underwater vehicle. This eliminates the need for additional energy sources, thus reducing the energy consumption of the underwater vehicle. Furthermore, when the push-pull rod drive mechanism 400 drives the first flexible membrane 200 to deform and thereby adjust the buoyancy of the underwater navigation device, the second flexible membrane 300 can passively compensate for the buoyancy change of the head portion 110 of the underwater navigation device, thereby preventing the underwater navigation device from losing weight and ensuring the stability of the underwater navigation device during buoyancy adjustment. The volume change of the swim bladder chamber 131 caused by the deformation of the first flexible membrane 200 is greater than the volume change of the swim bladder chamber 131 caused by the deformation of the second flexible membrane 300. This is to ensure that the push-pull rod drive mechanism 400 can change the volume of the underwater navigation device when driving the first flexible membrane 200 to deform. Specifically, when the push-pull rod drive mechanism 400 drives the first flexible membrane 200 to bulge toward the head portion 110, the first flexible membrane 200 will squeeze out the water in the head portion 110, and the second flexible membrane 300 will sink inward under the action of the water pressure. The volume change of the swim bladder chamber 131 caused by the deformation of the first flexible membrane 200 is greater than the volume change of the swim bladder chamber 131 caused by the deformation of the second flexible membrane 300. This causes the volume of the underwater navigation device to gradually increase when the push-pull rod drive mechanism 400 drives the first flexible membrane 200 to deform, which helps to expand the volume and increase the buoyancy during the ascent process, thereby reducing the energy consumption of ascent. Conversely, the volume of the underwater navigation device gradually decreases when the push-pull rod drives the first flexible membrane 200 to deform, which helps to contract the volume and reduce the buoyancy during the descent process, thereby reducing the energy consumption of descent. The tail fin propulsion mechanism 500 is used to provide propulsion for the underwater navigation device. This underwater navigation device has applications in underwater navigation robots, robotic fish, and other technical fields.

[0040] It should be noted that the underwater navigation device with a bionic fish swim bladder adopts a bionic fish swim bladder structure design and adjusts buoyancy by changing its own volume to achieve floating and sinking. Specifically, according to Archimedes' derivation: F 浮 =ρ 液 gV 排 Under the condition that the liquid density and gravitational acceleration remain constant, as the volume of the underwater vehicle increases, the buoyancy it experiences also increases. Conversely, as the volume of the underwater vehicle decreases, the volume of water it displaces also decreases, and the buoyancy it experiences also decreases. Furthermore, the first flexible membrane 200 is primarily used in scenarios requiring high-precision control, while the second flexible membrane 300 is primarily used in scenarios where frequent buoyancy adjustment is not required to reduce energy consumption. In a specific embodiment, both the first flexible membrane 200 and the second flexible membrane 300 are equipped with flexible sensors. These sensors are embedded in the flexible membranes using stretchable flexible electronic materials to acquire real-time sensor data such as tensile stress and pressure of the first and second flexible membranes. In this embodiment, the second flexible membrane 300 also facilitates the generation of a pitching moment, thereby enabling the underwater navigation device to achieve a preset pitch attitude. Specifically, when the underwater navigation device needs to be adjusted to a buoyant attitude, the push-pull rod drive mechanism 400 drives the first flexible membrane 200 to bulge toward the head 110, and the second flexible membrane 300 contracts inward under the action of water pressure. This facilitates converting the shape change of the swim bladder chamber 131 into a pitching moment, thereby enabling the underwater navigation device to achieve a preset pitch attitude. Furthermore, it should be noted that in this embodiment, since the center of gravity is located between the first and second flexible membranes, the active adjustment of the first flexible membrane and the anti-phase expansion and contraction of the second flexible membrane can generate pitching moments in the same direction. This facilitates generating a pitching attitude and buoyancy when the first flexible membrane is extended, and generating a pitching attitude and descent when the first flexible membrane is retracted.

[0041] See also Figure 2 In one embodiment of the present invention, the push-pull rod drive mechanism 400 includes a fixed base 410, a driving member 420, and a pushing block 430. Both the driving member 420 and the pushing block 430 are mounted on the fixed base 410. The pushing block 430 is connected to the output end of the driving member 420 and abuts against the first flexible membrane 200. The driving member 420 is used to drive the pushing block 430 toward or away from the head 110 to cause the first flexible membrane 200 to deform. In this embodiment, the driving member 420 drives the pushing block 430 toward or away from the head 110 to cause the first flexible membrane 200 to deform. This simplifies the structure of the underwater navigation device and reduces the difficulty of manufacturing the underwater navigation device. In a specific embodiment, the driving member 420 may be a drive motor.

[0042] See also Figure 2 In an embodiment of the present application, the pushing block 430 is arranged in the fixed seat 410 in a spaced manner with the driving member 420, the pushing block 430 comprises an inner rod 431 and an outer tube 432 arranged coaxially, the inner rod 431 is arranged in the fixed seat 410 in a rotatable manner, and the inner rod 431 is arranged in the outer tube 432 in a threaded connection manner; the driving member 420 is used to drive the inner rod 431 to rotate, and then drive the outer tube 432 to move towards or away from the head 110. In the embodiment, by designing the pushing block 430 as a nested structure composed of the inner rod 431 and the outer tube 432, the distance of the pushing block 430 moving towards or away from the head 110 can be improved, so as to improve the space utilization of the underwater navigation device, and make the structure of the underwater navigation device more compact. Specifically, the driving member 420 drives the inner rod 431 to rotate through the cooperation of a synchronous wheel and a synchronous belt, and then drives the outer tube 432 to move towards or away from the head 110. In a specific embodiment, the fixed seat 410 is provided with a sleeve 411, and the outer tube 432 is arranged in the sleeve 411 in a sliding manner; by arranging the outer tube 432 in the sleeve 411 in a sliding manner, the movement of the outer tube 432 can be guided, so as to ensure the stability and accuracy of the movement of the outer tube 432 towards or away from the head 110. In order to ensure that the rotation of the inner rod 431 can be converted into the linear motion of the outer tube 432, the outer tube 432 needs to avoid rotating with the inner rod 431; specifically, the following structure can be used to achieve the above-mentioned purpose, the sleeve 411 and the outer tube 432 are provided with matched limiting blocks and limiting grooves extending along the central axis of the outer tube 432, and the limiting blocks are arranged in the limiting grooves in a sliding manner.

[0043] Please refer to Figure 2 In an embodiment of the present application, the pushing block 430 is provided with a pushing head 433, and the pushing head 433 is provided with an arc surface 4331 abutting against the first flexible film 200. In the embodiment, by arranging the pushing head 433 on the pushing block 430, and abutting the arc surface 4331 of the pushing head 433 against the first flexible film 200, the first flexible film 200 can be better protected, and damage of the first flexible film 200 during deformation can be avoided. In a specific embodiment, the pushing head 433 can be an arc-shaped plate.

[0044] In one embodiment of the present invention, the elasticity of the first flexible membrane 200 is greater than that of the second flexible membrane 300; and / or the area of ​​the first flexible membrane 200 is greater than that of the second flexible membrane 300; and / or the thickness of the first flexible membrane 200 is less than that of the second flexible membrane 300. In this embodiment, by ensuring that the elasticity of the first flexible membrane 200 is greater than that of the second flexible membrane 300, the area of ​​the first flexible membrane 200 is greater than that of the second flexible membrane 300, and the thickness of the first flexible membrane 200 is less than that of the second flexible membrane 300, it is possible to ensure that the volume change of the swim bladder chamber 131 caused by deformation of the first flexible membrane 200 is greater than the volume change of the swim bladder chamber 131 caused by deformation of the second flexible membrane 300. This ensures that the push-pull rod driving mechanism 400 can change the volume of the underwater navigation device when driving the deformation of the first flexible membrane 200.

[0045] See also Figure 3 In one embodiment of the present invention, the tail fin drive mechanism 520 includes a drive unit 521, which is connected in sequence, and a shaft 522, a connecting rod 523, and a swing arm 524, which are hinged in sequence. The bionic tail fin 510 is rotatably mounted on the tail portion 120 via a rotating shaft. The shaft 522 is connected to the output end of the drive unit 521, and the swing arm 524 is hinged to the rotating shaft, with the swing arm 524 being disposed at an angle to the rotating shaft. The connecting rod 523 is disposed at an angle to the shaft 522 and the swing arm 524. Specifically, the drive unit 521 is configured to drive the shaft 522 to rotate, thereby driving the connecting rod 523 to rotate about the central axis of the shaft 522 and the swing arm 524 to rotate about the central axis of the shaft 522. This causes the end of the swing arm 524, which is away from the rotating shaft, to perform circular motion in a vertical plane, thereby driving the rotating shaft to rotate back and forth, causing the bionic tail fin 510 to swing back and forth, providing the propulsion required for the underwater navigation device to move forward.

[0046] See also Figure 4In one embodiment of the present invention, the underwater navigation device with a bionic swim bladder further includes a pectoral fin flapping mechanism 600. The pectoral fin flapping mechanism 600 includes a bionic pectoral fin 610 and a pectoral fin drive mechanism 620. The pectoral fin drive mechanism 620 is disposed within the housing 100. The bionic pectoral fin 610 is rotatably mounted on the pectoral fin drive mechanism 620 and extends out of the main body 130. The pectoral fin drive mechanism 620 is used to drive the bionic pectoral fin 610 to swing about its rotation axis and to drive the end of the bionic pectoral fin 610 away from the main body 130 to rotate toward or away from the head 110. In this embodiment, the pectoral fin drive mechanism 620 drives the bionic pectoral fin 610 to move, achieving bionic flapping motion with two rotational degrees of freedom, thereby improving the maneuverability of the underwater navigation device during underwater movement. Specifically, the pectoral fin drive mechanism 620 can drive the bionic pectoral fin 610 to swing about its rotation axis, achieving pitch motion of the bionic pectoral fin 610, mimicking the up-and-down swinging of a fish's pectoral fin. Simultaneously, the pectoral fin drive mechanism 620 can also drive the end of the bionic pectoral fin 610 away from the main body 130 toward or away from the head 110, achieving torsional motion of the bionic pectoral fin 610, mimicking the forward and backward swinging of a fish's pectoral fin. Furthermore, by integrating the motions of the bionic caudal fin 510 and the bionic pectoral fin 610, an amplitude-adjustable swinging motion of the bionic caudal fin 510 and a two-degree-of-freedom flapping motion of the bionic pectoral fin 610 are achieved, enabling the underwater navigation device to possess high-speed and highly maneuverable propulsion capabilities.

[0047] See also Figure 4 In one embodiment of the present invention, the pectoral fin drive mechanism 620 includes a bracket 621, a first servo 622, a second servo 623, and a transmission member 624 disposed on the bracket 621. The bionic pectoral fin 610 is rotatably disposed on the transmission member 624. The first servo 622 drives the bionic pectoral fin 610 to rotate around the vertical direction of the transmission member 624 through the transmission member 624, so that the end of the bionic pectoral fin 610 away from the main body 130 rotates toward or away from the head 110. The second servo 623 drives the bionic pectoral fin 610 to swing around its rotation axis through the transmission member 624. The vertical direction of the transmission member 624 is as follows: Figure 4 As shown in Z in FIG, the rotation axis of the bionic pectoral fin 610 is as shown in FIG. Figure 4 In this embodiment, two servos are used to respectively drive the bionic pectoral fin 610 to swing around its rotation axis and to rotate around the vertical direction of the transmission member 624, thereby avoiding interference caused by the multi-directional rotation of the bionic pectoral fin 610 and ensuring the accuracy of the bionic pectoral fin 610 during movement.

[0048] See also Figure 4In an embodiment of the present application, the transmission member 624 comprises a housing 6241 and a helical gear 6242 arranged in the housing 6241, one end of the bionic pectoral fin 610 is arranged in the housing 6241 and engaged with the helical gear 6242, the support 621 is further provided with a first synchronous wheel 6211, a second synchronous wheel 6212, and coaxially nested first and second shafts, the first shaft is connected with the first synchronous wheel 6211 and the housing 6241, and the second shaft is connected with the helical gear 6242; the first steering engine 622 drives the first shaft to rotate through the first synchronous belt and the first synchronous wheel 6211, thereby driving the housing 6241 to rotate around the vertical direction of the transmission member 624, so as to drive the bionic pectoral fin 610 to rotate around the vertical direction of the transmission member 624; the second steering engine 623 drives the second shaft to rotate through the second synchronous belt and the second synchronous wheel 6212, thereby driving the helical gear 6242 to rotate, so as to drive the bionic pectoral fin 610 to swing around its rotation axis. The underwater navigation device with the bionic swim bladder realizes the rotation of the bionic pectoral fin 610 around the vertical direction of the transmission shaft and the swing of the bionic pectoral fin 610 around its rotation axis by adopting the coaxial nested structure design and the coupling design of the helical gear 6242, and driving by independent steering engines, that is, the bionic pectoral fin 610 simulates the up-down swing and the front-back swing of the pectoral fin of fish; it can simplify the structure of the underwater navigation device, reduce the structural complexity, and make the structure of the underwater navigation device more compact; at the same time, it can also avoid the interference of the bionic pectoral fin 610 during multi-direction rotation, and ensure the accuracy of the bionic pectoral fin 610 during movement. In this embodiment, the two rotation degrees of freedom of the transmission member 624 are conjugate, and the rotation angles of the two steering engines and the inclination angles of the fin surface of the bionic pectoral fin 610 along the two conjugate axes are the same.

[0049] In an embodiment of the present application, the underwater navigation device with the bionic swim bladder is further provided with a sensor group, which comprises a visual sensor, a depth sensor and an inertial sensor. In this embodiment, the visual sensor is used to capture a wide range of visual information to provide a panoramic image of the underwater environment for the underwater navigation device, helping the underwater navigation device to identify the surrounding obstacles, terrain and other objects, so as to realize autonomous obstacle avoidance. The depth sensor is used to measure the depth of the underwater navigation device in water. The inertial sensor can measure the pitch angle and the yaw angle of the underwater navigation device in real time, and can also obtain the speed, acceleration and other motion state information of the underwater navigation device.

[0050] Furthermore, the integration of the first flexible membrane 200, the second flexible membrane 300, and the push-pull rod drive mechanism 400 into the underwater navigation device must meet three design principles: gravitational buoyancy balance, pitch attitude balance, and negative pressure in the swim bladder chamber 131. Specifically, to address the distribution of gravitational buoyancy, when the push block 430 of the push-pull rod drive mechanism 400 is in a neutral position, neutral buoyancy is achieved by adjusting the overall size and mass of the underwater navigation device. Furthermore, by adjusting the spatial layout of the push-pull rod drive mechanism 400, the tail fin propulsion mechanism 500, and the pectoral fin propulsion mechanism 600 within the swim bladder chamber 131, the initial moment of inertia is adjusted to maximize the length of the lever arm generated by the underwater navigation device due to buoyancy changes, thereby maximizing the control effect of the push-pull rod drive mechanism 400. Regarding the air pressure in the swim bladder chamber 131, when the push block 430 of the push-pull rod drive mechanism 400 is fully retracted, the air pressure inside the cabin and outside is designed to be equal, so that when the push block 430 is in any position, the swim bladder chamber 131 is under negative pressure, so that the second flexible membrane 300 is in an opposite phase to the first flexible membrane 200 under the action of water pressure, meeting the negative pressure principle in the cabin.

[0051] See also Figure 5 , Figure 5 The present invention also provides a motion control method, which is applied to the above-mentioned underwater navigation device with a bionic swim bladder. The motion control method includes:

[0052] S100, obtaining current speed information, current heading information, and current pitch attitude information of the underwater navigation device having a bionic fish swim bladder;

[0053] S200, comparing the preset speed information with the current speed information, and controlling the tail fin drive mechanism 520 by the bionic tail fin controller according to an error value between the preset speed information and the current speed information to adjust the swimming speed of the underwater sailing device with the bionic fish swim bladder so that the underwater sailing device with the bionic fish swim bladder reaches the preset swimming speed;

[0054] S300, comparing the preset heading information with the current heading information, and controlling the pectoral fin drive mechanism 620 by the bionic pectoral fin controller based on an error value between the preset heading information and the current heading information to adjust the heading angle of the underwater navigation device with the bionic fish swim bladder so that the underwater navigation device with the bionic fish swim bladder reaches the preset heading angle;

[0055] S400, compare the preset pitch attitude information with the current pitch attitude information, and according to the error value between the preset pitch attitude information and the current pitch attitude information, the bionic fish maw controller controls the push-pull rod drive mechanism 400 to operate, and adjusts the pitch attitude and depth of the underwater navigation device with the bionic fish maw, so that the underwater navigation device with the bionic fish maw reaches the preset pitch attitude and depth.

[0056] In this embodiment, the motion control method is to enable the underwater navigation device to reach a preset swimming speed and attitude through feedback control. Specifically, when the underwater navigation device is moving, the current speed information, current heading information and current pitch attitude information of the underwater navigation device are first obtained; then the preset speed information and the current speed information are compared, and according to the error value between the two, the bionic tail fin controller adopts a proportional-differential control algorithm to control the tail fin drive mechanism 520 to operate, adjust the swimming speed of the underwater navigation device, and thus enable the underwater navigation device to reach the preset swimming speed; the preset heading information and the current heading information are compared, and according to the error value between the two, the bionic pectoral fin controller adopts a proportional-differential control algorithm to control the tail fin drive mechanism 520 to operate, adjust the swimming speed of the underwater navigation device, and then enable the underwater navigation device to reach the preset swimming speed. The algorithm controls the pectoral fin drive mechanism 620, adjusting the swing angle of the bionic pectoral fin 610 around its rotation axis and the vertical rotation angle around the transmission member 624, thereby causing the underwater vehicle to reach a preset heading angle. The algorithm then compares the preset pitch attitude information with the current pitch attitude information. Based on the error between the two, the bionic swim bladder controller uses a model predictive control method to control the push-pull rod drive mechanism 400. By adjusting the position of the push block 430, the pitch attitude and depth of the underwater vehicle are adjusted to achieve the preset pitch attitude and depth. The proportional-differential control algorithm is a control algorithm that adjusts the control variable based on an error signal and its rate of change (differential). In a specific embodiment, the proportional-differential control algorithm can be a PD control algorithm. The model predictive control method is based on the swim bladder control model in the dynamic model. The underwater vehicle's current speed, heading, and pitch attitude information are acquired via high-frequency sensors or observation sensors in the sensor group.

[0057] The above description is merely an exemplary embodiment of the present invention and does not limit the scope of protection of the present invention. Any equivalent structural transformation made by using the contents of the present invention description and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields, is included in the scope of protection of the present invention.

Claims

1. An underwater navigation device with a bionic fish swim bladder, characterized in that: The invention comprises a shell, a first flexible membrane, a second flexible membrane, a push-pull rod drive mechanism and a tail fin propulsion mechanism. The shell comprises a head, a tail and a main body connecting the head and the tail. The first flexible membrane is arranged between the head and the main body. The main body is provided with a notch. The second flexible membrane covers the notch. The first flexible membrane, the main body and the second flexible membrane enclose a swim bladder chamber. Definition: The volume change of the swim bladder chamber caused by the deformation of the first flexible membrane is ΔV1, and the volume change of the swim bladder chamber caused by the deformation of the second flexible membrane is ΔV2; then: |ΔV1|>|ΔV2|; The push-pull rod driving mechanism is arranged in the swim bladder chamber and is used to drive the deformation of the first flexible membrane. The tail fin propulsion mechanism includes a bionic tail fin and a tail fin driving mechanism. The bionic tail fin is rotatably arranged on the tail; the tail fin driving mechanism is arranged in the shell and is used to drive the bionic tail fin to swing.

2. The underwater navigation device with a bionic fish swim bladder according to claim 1, characterized in that: The push-pull rod driving mechanism includes a fixed seat, a driving member and a pushing block, wherein the driving member and the pushing block are both arranged on the fixed seat, and the pushing block is connected to the output end of the driving member and abuts against the first flexible film; The driving member is used to drive the pushing block to move toward or away from the head, so as to drive the first flexible membrane to deform.

3. The underwater navigation device with a bionic fish swim bladder according to claim 2, characterized in that: The pushing block and the driving member are arranged at intervals on the fixed seat, and the pushing block includes an inner rod and an outer tube arranged coaxially. The inner rod is rotatably arranged on the fixed seat, and the inner rod is passed through the outer tube and is threadedly connected to the outer tube; the driving member is used to drive the inner rod to rotate, thereby driving the outer tube to move toward or away from the head.

4. The underwater navigation device with a bionic fish swim bladder according to claim 2, characterized in that: The pushing block is provided with a pushing head, and the pushing head is provided with a curved surface abutting against the first flexible film.

5. The underwater navigation device with a bionic fish swim bladder according to claim 1, characterized in that: Both the first flexible film and the second flexible film are embedded with flexible sensors; the elasticity of the first flexible film is greater than the elasticity of the second flexible film; and / or the area of ​​the first flexible film is greater than the area of ​​the second flexible film; and / or the thickness of the first flexible film is less than the thickness of the second flexible film.

6. The underwater navigation device with a bionic fish swim bladder according to claim 1, characterized in that: The tail fin driving mechanism includes a driving unit connected in sequence, and a shaft, a connecting rod and a swing arm hinged in sequence. The bionic tail fin is rotatably arranged on the tail through a rotating shaft. The shaft is connected to the output end of the driving unit. The swing arm is hinged to the rotating shaft, and the swing arm is set at an angle to the rotating shaft. The connecting rod is set at an angle to the shaft and to the swing arm.

7. The underwater navigation device with a bionic fish swim bladder according to claim 1, characterized in that: The underwater navigation device with a bionic swim bladder also includes a pectoral fin flapping mechanism, which includes a bionic pectoral fin and a pectoral fin driving mechanism. The pectoral fin driving mechanism is arranged in the shell, and the pectoral fin driving mechanism includes a bracket, a first servo arranged on the bracket, a second servo and a transmission member, and the bionic pectoral fin is rotatably arranged on the transmission member; the first servo drives the bionic pectoral fin to rotate around the vertical direction of the transmission member through the transmission member, so that the bionic pectoral fin rotates away from one end of the main body toward or away from the head, and the second servo drives the bionic pectoral fin to swing around its rotation axis through the transmission member.

8. The underwater navigation device with a bionic fish swim bladder according to claim 7, characterized in that: The transmission member includes a housing and a helical gear disposed in the housing. One end of the bionic pectoral fin is disposed in the housing and meshes with the helical gear. The bracket is further provided with a first synchronous wheel, a second synchronous wheel, and a first shaft and a second shaft coaxially nested. The first shaft connects the first synchronous wheel and the housing, and the second shaft connects to the helical gear. The first servo drives the first shaft to rotate through the first synchronous belt and the first synchronous wheel, thereby driving the shell to rotate around the vertical direction of the transmission member to drive the bionic pectoral fin to rotate around the vertical direction of the transmission member; the second servo drives the second shaft to rotate through the second synchronous belt and the second synchronous wheel, thereby driving the bevel gear to rotate to drive the bionic pectoral fin to swing around its rotation axis.

9. The underwater navigation device with a bionic fish swim bladder according to any one of claims 1 to 8, characterized in that: The underwater navigation device with the bionic fish swim bladder is further provided with a sensor group, which includes a visual sensor, a depth sensor and an inertial sensor.

10. A motion control method, applied to the underwater navigation device with a bionic swim bladder according to any one of claims 1 to 9, characterized in that: The motion control method comprises: Acquiring current speed information, current heading information, and current pitch attitude information of the underwater navigation device having a bionic fish swim bladder; Comparing the preset speed information with the current speed information, and controlling the tail fin drive mechanism by the bionic tail fin controller according to an error value between the preset speed information and the current speed information, thereby adjusting the swimming speed of the underwater sailing device with the bionic fish swim bladder so that the underwater sailing device with the bionic fish swim bladder reaches the preset swimming speed; Comparing the preset heading information with the current heading information, and controlling the pectoral fin drive mechanism by the bionic pectoral fin controller according to an error value between the preset heading information and the current heading information, thereby adjusting the heading angle of the underwater sailing device with the bionic fish swim bladder so that the underwater sailing device with the bionic fish swim bladder reaches the preset heading angle; The preset pitch attitude information and the current pitch attitude information are compared. According to the error value between the preset pitch attitude information and the current pitch attitude information, the bionic fish maw controller controls the operation of the push-pull rod driving mechanism to adjust the pitch attitude and depth of the underwater navigation device with the bionic fish maw so that the underwater navigation device with the bionic fish maw reaches the preset pitch attitude and depth.

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