An adaptive bistable flexible biomimetic robotic fish

Abstract

The adaptive bistable flexible bionic robotic fish is modeled according to a real fish in an equal proportion, and specifically comprises a rigid fish head 1, a rigid fish body hatch cover 2, a flexible fish body 3 and a flexible tail fin 4; the rigid fish body hatch cover 2 is arranged on the rigid fish head 1, the rigid fish head 1, the flexible fish body 3 and the flexible tail fin 4 are sequentially and sealingly connected, the rigid fish head 1 comprises a hollow fish head cabin 101 and a fish head shell 102, and the fish head cabin 101 is internally provided with a driving module 5, an adaptive bistable module 6 and a control module 7. The adaptive bistable module is introduced, wherein the front spring and the rear spring are always in a pre-tensioned state, which is beneficial to store kinetic energy as elastic potential energy of the spring, realizes that fluid medium energy supply and adaptive bistable module energy supply are alternately performed, overcomes the defect that a large amount of energy is required to break through the barrier of a traditional bistable mechanism, and is applied to the driving of the bionic robotic fish, so that the flexible bionic robotic fish swims more quietly, faster and farther under the same power consumption.

Description

Technical Field

[0001] This invention relates to the field of biomimetic robotic fish, and more specifically to an adaptive bistable flexible biomimetic robotic fish. Background Technology

[0002] With the development of marine engineering technology, the development and use of underwater robots capable of adapting to various complex seabed environments has become particularly important, driving the development of underwater robots. However, underwater robots are subject to various environmental limitations when performing designated tasks in the water. To achieve complex movements, underwater robots need high speed and acceleration, as well as a small turning radius. Therefore, improving the swimming performance of underwater robots has become a core focus of underwater robot research. The drive mechanism, as the power / motion device of the underwater robot, directly affects or determines the performance of biomimetic robotic fish, such as swimming speed, efficiency, and maneuverability. In the development of biomimetic robotic fish, researchers at home and abroad have tried to use electric motors or hydraulic drives combined with different types of rigid drive mechanisms such as rods, hinges, and eccentric cams to achieve the movement of biomimetic robots. The results have shown that, compared with traditional propeller-driven robots, these actuators have advantages such as high propulsion efficiency and good maneuverability, and have also demonstrated better performance in practical applications. However, these rigid bionic robots also have drawbacks such as large size, difficulty in achieving flexible movement, and propulsion efficiency that cannot match that of real organisms. Many problems still exist in terms of service life, intelligent control, and maneuverability. How to design more realistic, flexible bionic robotic fish that can reduce energy consumption while increasing swimming speed and distance has become a research direction for further development of bionic robotic fish. Summary of the Invention

[0003] This invention aims to reduce energy consumption, increase the flexibility of the fish body, increase swimming speed, and extend the swimming distance of the robotic fish. Through a cleverly designed adaptive bistable module, it reduces the energy barrier of the traditional bistable mechanism, reduces the energy required for the flexible robotic fish to swing its body, and increases the instantaneous speed of the swing, thereby achieving a more efficient drive for the flexible bionic robotic fish and realizing the design of a new type of flexible bionic robotic fish.

[0004] The present invention adopts the following technical solution: An adaptive bistable flexible biomimetic robotic fish, modeled to scale with a real fish, specifically includes: a rigid fish head 1, a rigid fish body cover 2, a flexible fish body 3, and a flexible tail fin 4; wherein, the rigid fish body cover 2 is disposed on the rigid fish head 1, and the rigid fish head 1, flexible fish body 3, and flexible tail fin 4 are sequentially and sealed together; the rigid fish head 1 includes a hollow fish head chamber 101 and a fish head shell 102, and the fish head chamber 101 houses a drive module 5, an adaptive bistable module 6, and a control module 7; under the intelligent control of the control module 7, a portion of the mechanical energy generated by the drive module 5 is used for... The flexible fish body 3 is driven to bend to one side, which is the fluid medium energy supply stage. Due to the function of the adaptive bistable module 6, another part of the mechanical energy is stored as the elastic potential energy of the adaptive bistable module. The stored elastic potential energy is released after the flexible fish body 3 has just passed the straightened state, causing the flexible fish body 3 to continue to bend to the other side. This is the adaptive bistable module energy supply stage. The fluid medium energy supply stage and the adaptive bistable module energy supply stage alternate, so that the flexible fish body 3 bends alternately, causing the flexible tail fin 4 to swing back and forth accordingly.

[0005] The drive module 5 includes a battery 501, a motor bracket 502, a servo motor 503, a coupling 504, a liquid storage tank 505, a gear pump 506, a two-position five-way solenoid valve 507, and a connecting pipe 508. The battery 501 is located at the front end of the fish head compartment 101, and one side of the battery 501 is connected to the motor bracket 502. The servo motor 503 is installed inside the motor bracket 502, and the liquid storage tank 505 is installed on top of the motor bracket 502. The servo motor 503 is connected to the gear pump 506 through the coupling 504. One side of the gear pump 506 is directly connected to the liquid storage tank 505, and the other side of the gear pump 506 is connected to one end of the connecting pipe 508. The other end of the connecting pipe 508 is connected to the flexible fish body 3. The two-position five-way solenoid valve 507 is installed on the connecting pipe 508. The control module 7 is electrically or wirelessly connected to the two-position five-way solenoid valve 507 and the servo motor 503. The battery 501 is used to power the servo motor 503, the two-position five-way solenoid valve 507 and the control module 7. The adaptive bistable module 6 is adjacent to the drive module 5. The adaptive bistable module 6 includes a column 601, a triangular bracket 602, slide rails 603, a front spring 604, a slider 605, a rear spring 606, a pull rod 607, and a limiting member 608. The column 601 is fixedly installed in the fish head compartment 101. The triangular bracket 602 is horizontally arranged on one side of the column 601. Two parallel slide rails 603 are arranged at the center of the triangular bracket 602. The slider 605 is slidably arranged within the two slide rails 603. The limiting member 608 is provided at the end of 03 to prevent the slider 605 from falling out. One side of the slider 605 is connected to the column 601 through the front spring 604, and the other side of the slider 605 is connected to one end of the rear spring 606. The other end of the rear spring 606 passes through the flexible fish body 3 and is connected to the front end of the pull rod 607. The rear end of the pull rod 607 is fixed on the flexible tail fin 4. The front spring 604 and the rear spring 606 are always kept in a pre-stretched state.

[0006] Furthermore, the flexible fish body 3 has a split structure, divided into a completely symmetrical left fish body and a right fish body. The left and right fish bodies are made of flexible material, which can be repeatedly bent and deformed to a large extent but cannot be stretched axially. The structure of the right fish body is exactly the same as that of the left fish body. The left fish body includes a semi-conical shell 301, a cavity cover 302, and a semi-conical cavity 303. The semi-conical shell 301 and the cavity cover 302 are integrally formed. The interior of the semi-conical shell 301 and the cavity cover 302 is the semi-conical cavity 303. Multiple longitudinally parallel semi-circular ribs 304 are fixedly arranged inside the semi-conical cavity 303. The multiple semi-circular ribs 304 are evenly spaced and divide the semi-conical cavity 303 into multiple... Each chamber has a plurality of semi-circular ribs 304 with gradually decreasing diameters to match the inner diameter of the semi-conical cavity 303. The cavity cover 302 is provided with a first hollowed-out arc groove 305. Each semi-circular rib 304 has a second hollowed-out arc groove 306 at its center. A liquid inlet / outlet 307 is provided near the first hollowed-out arc groove 305. A cavity connecting hole 308 is provided near the second hollowed-out arc groove 306. The tail of the left side of the fish body is solid. A cavity outlet channel 309 is provided on the central axis of the tail of the left side of the fish body. The first hollowed-out arc groove 305, the second hollowed-out arc groove 306 and the cavity outlet channel 309 are located on the same straight line. The liquid inlet / outlet 307 is connected to the connecting pipe 508.

[0007] Furthermore, the flexible fish body 3 also includes a trapezoidal intermediate sealing cover plate 3010, which is positioned in the middle of the left and right sides of the fish body. The intermediate sealing cover plate 3010 is sealed to both the left and right sides of the fish body to prevent liquid from flowing out. An arc-shaped protrusion structure 3011 is provided on the central axis of the intermediate sealing cover plate 3010. The arc-shaped protrusion structure 3011 is adapted to and sealed with the first hollowed-out arc groove 305 and the second hollowed-out arc groove 306 on both sides. The arc-shaped protrusion structure 3011 is hollow inside. The rear spring 606 passes through the interior of the arc-shaped protrusion structure 3011 and is connected to the front end of the pull rod 607. The front end of the pull rod 607 is fixed to the rear end of the arc-shaped protrusion structure 3011. The pull rod 607 is still placed in the chamber outlet channel 309.

[0008] Furthermore, the rigid fish head 1 is processed using 3D printing technology, and the flexible tail fin 4 is manufactured using injection molding.

[0009] Furthermore, the rigid fish head 1 and the flexible fish body 3 are fixedly connected by positioning pins and screws to ensure that the rigid fish head 1 and the flexible fish body 3 do not rotate relative to each other, and waterproof sealant is applied to the joint to prevent relative sliding and water leakage.

[0010] Furthermore, the control module 7 is used to control the start / stop and speed of the servo motor 503 and the potential of the two-position five-way solenoid valve 507, thereby controlling the swing frequency and swing amplitude of the flexible bionic robotic fish.

[0011] Furthermore, both the flexible fish body 3 and the flexible tail fin 4 are made of polymer flexible material and are fixedly connected by positioning pins and screws.

[0012] Furthermore, the intermediate sealing cover plate 3010 is formed by casting a mixture of colloid and fiber cloth, and can be repeatedly bent but cannot be stretched axially.

[0013] Furthermore, the internal space of the arc-shaped protrusion structure 3011 is sufficient so that during the swimming process of the adaptive bistable flexible bionic robotic fish, the rear spring 606 and the arc-shaped protrusion structure 3011 never come into contact, thus avoiding mutual interference.

[0014] The beneficial effects of this invention are as follows: (1) By introducing an adaptive bistable module, the front and rear springs of this invention are always in a pre-stretched state, which helps to store kinetic energy as the elastic potential energy of the springs. This overcomes the disadvantage of traditional bistable mechanisms requiring a large amount of energy to break through the potential barrier. This invention is applied to the drive of a biomimetic robotic fish, enabling the flexible biomimetic robotic fish to swim more quietly, faster, and farther with the same power consumption. Another major advantage of this invention is that the flexible fish body has better compliance. By designing a control system, the robotic fish can achieve multi-form and large-angle swimming, which is closer to the swimming posture of real fish and has higher swimming efficiency.

[0015] (2) Fluid medium power supply + adaptive bistable module power supply, alternating between the two. Part of the mechanical energy generated by the drive module is used to drive the flexible fish body to bend and deform (this is fluid medium power supply). Since the front spring and the rear spring are always in a pre-stretched state, the other part is stored as the elastic potential energy of the adaptive bistable module. The stored elastic potential energy is released after the flexible fish body has just passed the straightened state in the bending state, causing the flexible fish body to continue to bend to the other side (this is adaptive bistable module power supply). That is, the fluid medium power supply stage and the adaptive bistable module power supply stage alternate between the two, resulting in lower energy consumption. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the shape of the biomimetic robotic fish of the present invention.

[0017] Figure 2 This is a schematic diagram of the rigid fish head structure of the present invention.

[0018] Figure 3 This is a schematic diagram of the flexible fish body structure on the left side of the present invention.

[0019] Figure 4 This is a schematic diagram of the intermediate sealing cover structure of the flexible fish body of the present invention.

[0020] Figure 5 This is a schematic diagram of the adaptive bistable module of the present invention.

[0021] Figure 6 This is a schematic diagram illustrating the swimming principle of the biomimetic robotic fish of this invention.

[0022] In the diagram: 1. Rigid fish head; 101. Fish head chamber; 102. Fish head shell; 103. Fish head and body connecting screws; 2. Rigid fish body cover; 3. Flexible fish body; 301. Semi-conical shell; 302. Cavity cover; 303. Semi-conical cavity; 304. Semi-circular rib; 305. First hollowed-out arc groove; 306. Second hollowed-out arc groove; 307. Liquid inlet / outlet; 308. Cavity connecting hole; 309. Cavity outlet channel; 4. Flexible tail fin; 5. Drive 501. Motion module, battery, motor bracket, servo motor, coupling, liquid storage tank, gear pump, 2-position 5-way solenoid valve, connecting pipe; 6. Adaptive bistable mechanism, column, triangular bracket, slide rail, front spring, slider, rear spring, tie rod, limit component; 7. Control module. Detailed Implementation

[0023] The invention will now be described in more detail with reference to the accompanying drawings: like Figure 1 As shown, the yellowfin tuna, as one of the top predators in the ocean, swims at extremely high speeds. The reasons for its high speed can be summarized in two points: firstly, the streamlined shape of its body; and secondly, the length, frequency, and amplitude of its body movements during swimming. Based on the swimming characteristics of real yellowfin tuna, the flexible biomimetic robotic fish of this invention is modeled proportionally to the real yellowfin tuna. The length of the flexible body is designed to perfectly match the length of the real yellowfin tuna involved in its undulating movements, and the streamlined shape is also modeled to perfectly match the real yellowfin tuna's shape, thereby reducing drag and achieving maximum swimming speed. An adaptive bistable flexible biomimetic robotic fish, modeled proportionally to a real fish, specifically includes: a rigid fish head 1, a rigid fish body hatch 2, a flexible fish body 3, and a flexible tail fin 4. The rigid fish body hatch 2 is disposed on the rigid fish head 1, and the rigid fish head 1, flexible fish body 3, and flexible tail fin 4 are sequentially and sealed together.

[0024] like Figure 2As shown, the rigid fish head 1 includes a hollow fish head chamber 101 and a fish head shell 102. The fish head chamber 101 houses a drive module 5, an adaptive bistable module 6, and a control module 7. The drive module 5 includes a battery 501, a motor bracket 502, a servo motor 503, a coupling 504, a liquid storage tank 505, a gear pump 506, a two-position five-way solenoid valve 507, and a connecting pipe 508. The battery 501 is located at the front end of the fish head chamber 101, with one side connected to the motor bracket 502. The servo motor 503 is housed inside the motor bracket 502, and the liquid storage tank 505 is mounted on top of the motor bracket 502. The motor 503 is connected to the gear pump 506 via the coupling 504. One side of the gear pump 506 is directly connected to the liquid storage tank 505, and the other side of the gear pump 506 is connected to one end of the connecting pipe 508. The other end of the connecting pipe 508 is connected to the flexible fish body 3. The two-position five-way solenoid valve 507 is installed on the connecting pipe 508. The control module 7 is electrically or wirelessly connected to the two-position five-way solenoid valve 507 and the servo motor 503. The battery 501 is used to power the servo motor 503, the two-position five-way solenoid valve 507 and the control module 7. The adaptive bistable module 6 is adjacent to the drive module 5.

[0025] like Figure 3 The diagram shows the left flexible fish body structure of the present invention. The flexible fish body 3 is a split structure, divided into a completely symmetrical left fish body and a right fish body. The left and right fish bodies are made of flexible material, which can be repeatedly bent and deformed to a large extent but cannot be stretched axially. The structure of the right fish body is exactly the same as that of the left fish body. The left fish body includes a semi-conical shell 301, a cavity cover 302, and a semi-conical cavity 303. The semi-conical shell 301 and the cavity cover 302 are integrally formed. The interior of the semi-conical shell 301 and the cavity cover 302 is the semi-conical cavity 303. Multiple longitudinally parallel semi-circular ribs 304 are fixedly arranged inside the semi-conical cavity 303. The multiple semi-circular ribs 304 are evenly spaced and arranged to support the semi-conical cavity 303. The structure is divided into multiple chambers. The diameter of the multiple semi-circular ribs 304 gradually decreases to match the inner diameter of the semi-conical cavity 303. The cavity cover 302 is provided with a first hollowed-out arc groove 305. A second hollowed-out arc groove 306 is provided at the center of each semi-circular rib 304. A liquid inlet / outlet 307 is provided near the first hollowed-out arc groove 305. A chamber connecting hole 308 is provided near the second hollowed-out arc groove 306. The tail of the left side of the fish body is solid. A chamber outlet channel 309 is provided on the central axis of the tail of the left side of the fish body. The first hollowed-out arc groove 305, the second hollowed-out arc groove 306 and the chamber outlet channel 309 are located on the same straight line. The liquid inlet / outlet 307 is connected to the connecting pipe 508.

[0026] like Figure 4 As shown, the flexible fish body 3 also includes a trapezoidal intermediate sealing cover plate 3010. The intermediate sealing cover plate 3010 is placed in the middle of the left and right fish bodies. The intermediate sealing cover plate 3010 seals with both the left and right fish bodies to prevent liquid from flowing out. An arc-shaped protrusion structure 3011 is provided on the central axis of the intermediate sealing cover plate 3010. The arc-shaped protrusion structure 3011 is adapted to and seals with the first hollowed-out arc groove 305 and the second hollowed-out arc groove 306 on both sides. The arc-shaped protrusion structure 3011 is hollow inside. The rear spring 606 passes through the inside of the arc-shaped protrusion structure 3011 and is connected to the front end of the pull rod 607. The front end of the pull rod 607 is fixed to the rear end of the arc-shaped protrusion structure 3011. The pull rod 607 is still placed in the chamber outlet channel 309.

[0027] like Figure 5 As shown, the adaptive bistable module 6 includes a column 601, a triangular bracket 602, a slide rail 603, a front spring 604, a slider 605, a rear spring 606, a pull rod 607, and a limiting member 608. The column 601 is fixedly installed in the fish head compartment 101. The triangular bracket 602 is horizontally arranged on one side of the column 601. Two parallel slide rails 603 are arranged at the center of the triangular bracket 602. The slider 605 is slidably arranged within the two slide rails 603. The limiting member 608 is provided at the end of the rail 603 to prevent the slider 605 from falling out. One side of the slider 605 is connected to the column 601 through the front spring 604, and the other side of the slider 605 is connected to one end of the rear spring 606. The other end of the rear spring 606 passes through the flexible fish body 3 and is connected to the front end of the pull rod 607. The rear end of the pull rod 607 is fixed on the flexible tail fin 4. The front spring 604 and the rear spring 606 are always kept in a pre-stretched state.

[0028] Furthermore, the rigid fish head 1 is processed using 3D printing technology, and the flexible tail fin 4 is manufactured using injection molding.

[0029] Furthermore, the rigid fish head 1 and the flexible fish body 3 are fixedly connected by positioning pins and screws to ensure that the rigid fish head 1 and the flexible fish body 3 do not rotate relative to each other, and waterproof sealant is applied to the joint to prevent relative sliding and water leakage.

[0030] Furthermore, the control module 7 is used to control the start / stop and speed of the servo motor 503 and the potential of the two-position five-way solenoid valve 507, thereby controlling the swing frequency and swing amplitude of the flexible bionic robotic fish.

[0031] Furthermore, both the flexible fish body 3 and the flexible tail fin 4 are made of polymer flexible material and are fixedly connected by positioning pins and screws.

[0032] Furthermore, the intermediate sealing cover plate 3010 is formed by casting a mixture of colloid and fiber cloth, and can be repeatedly bent but cannot be stretched axially.

[0033] Furthermore, the internal space of the arc-shaped protrusion structure 3011 is sufficient so that during the swimming process of the adaptive bistable flexible bionic robotic fish, the rear spring 606 and the arc-shaped protrusion structure 3011 never come into contact, thus avoiding mutual interference.

[0034] The adaptive bistable flexible bionic robotic fish oscillation principle is as follows: Figure 6As shown, the control module 7 controls the power supply 501 to de-energize the two-position five-way solenoid valve 507, causing the two-position five-way solenoid valve 507 to switch to a working state where fluid medium flows into the left side of the fish body and flows out of the right side of the fish body. Simultaneously, the control module 7 controls the gear pump 506 to operate, pumping the fluid medium from the right side of the fish body into the storage tank 505 through the chamber inlet / outlet 307. At the same time, the gear pump 506 pumps the fluid medium returning to the storage tank 505 into the left side of the fish body through the chamber inlet / outlet 307. The fluid medium quickly fills the chambers separated by the semi-circular ribs 304 through the chamber connecting holes 308. The internal pressure of the left side of the fish body causes the flexible fish body 3 to bend from the right side. The deformed state moves towards the axially straightened state. Simultaneously, the front spring 604 and rear spring 606 of the adaptive bistable module 6 are stretched and stored as elastic potential energy, thus charging the adaptive bistable module 6. This stage is the fluid medium energy supply stage. When the flexible fish body 3 changes from a right-side bent deformation state to just passing the axially straightened state, the control module 7 controls the gear pump 506 to stop operating. At this time, the elastic potential energy stored in the front spring 604 and rear spring 606 of the adaptive bistable module begins to be released, causing the flexible fish body 3 to bend to the left. This stage supplies energy to the adaptive bistable module. Thus, the flexible fish body 3 drives the flexible tail fin 4 to complete the movement from left to right. The control module 7 controls the power supply 501 to energize the two-position five-way solenoid valve 507, causing the valve to switch to a working state where fluid medium flows out of the left side of the fish body and flows into the right side. It also controls the gear pump 506 to pump the fluid medium from the left side of the fish body into the storage tank 505 through the chamber inlet / outlet 307. Simultaneously, the gear pump 506 pumps the fluid medium returning to the storage tank 505 into the right side of the fish body through the chamber inlet / outlet 307, rapidly filling the chambers separated by the semi-circular ribs 304 via the chamber connecting holes 308. The internal pressure of the right side of the fish body causes the flexible fish body 3 to bend and deform from the left side. When the flexible fish body 3 moves towards the axially taut state, the front spring 604 and rear spring 606 of the adaptive bistable module 6 are stretched and stored as elastic potential energy, which is the energy supply stage for the adaptive bistable module 6. When the flexible fish body 3 changes from the left-side bending deformation state to just passing the axially taut state, the control module 7 controls the gear pump 506 to stop operating. At this time, the elastic potential energy stored in the front spring 604 and rear spring 606 of the adaptive bistable module begins to be released, causing the flexible fish body 3 to bend to the right. This stage is the energy supply stage for the adaptive bistable module. Thus, the flexible fish body 3 drives the flexible tail fin 4 to complete one swing from right to left.Both the front and rear springs are always in a pre-stretched state. Part of the mechanical energy generated by the drive module is used to drive the flexible fish body to bend and deform, while the other part is stored as the elastic potential energy of the adaptive bistable module. The stored elastic potential energy is released just after the flexible fish body has passed its axial straightening state during bending, causing the flexible fish body to continue bending. This means that the fluid medium energy supply stage and the adaptive bistable module energy supply stage alternate. After loading the control program into control module 7, the continuous swinging motion of the adaptive bistable flexible bionic robotic fish can be realized.

Claims

1. An adaptive bistable flexible biomimetic robotic fish, characterized in that: The fish's shape is modeled to scale based on a real fish, specifically including: a rigid fish head (1), a rigid fish body hatch (2), a flexible fish body (3), and a flexible tail fin (4); wherein, the rigid fish body hatch (2) is set on the rigid fish head (1), and the rigid fish head (1), flexible fish body (3), and flexible tail fin (4) are sequentially and sealed together. The rigid fish head (1) includes a hollow fish head chamber (101) and a fish head shell (102). The fish head chamber (101) is equipped with a drive module (5), an adaptive bistable module (6), and a control module (7); under the intelligent control of the control module (7), the mechanical energy generated by the drive module (5) is... A portion is used to drive the flexible fish body (3) to bend to one side. This is the fluid medium energy supply stage. Due to the action of the adaptive bistable module (6), another portion of the mechanical energy is stored as the elastic potential energy of the adaptive bistable module. The stored elastic potential energy is released after the flexible fish body (3) has just passed the straightened state, causing the flexible fish body (3) to continue to bend to the other side. This is the adaptive bistable module energy supply stage. The fluid medium energy supply stage and the adaptive bistable module energy supply stage alternate, realizing the flexible fish body (3) to bend alternately, causing the flexible tail fin (4) to swing back and forth accordingly.

2. The adaptive bistable flexible biomimetic robotic fish according to claim 1, characterized in that, The drive module (5) includes a battery (501), a motor bracket (502), a servo motor (503), a coupling (504), a liquid storage tank (505), a gear pump (506), a two-position five-way solenoid valve (507), and a connecting pipe (508). The battery (501) is located at the front end of the fish head compartment (101). One side of the battery (501) is connected to the motor bracket (502). The servo motor (503) is installed inside the motor bracket (502). The liquid storage tank (505) is installed on top of the motor bracket (502). The servo motor (503) is connected to the gear pump (506) through the coupling (504). One side of the gear pump (506) is directly connected to the liquid storage tank (505), and the other side of the gear pump (506) is connected to one end of the connecting pipe (508). The other end of the connecting pipe (508) is connected to the flexible fish body (3). The two-position five-way solenoid valve (507) is installed on the connecting pipe (508). The control module (7) is electrically or wirelessly connected to the two-position five-way solenoid valve (507) and the servo motor (503). The battery (501) is used to power the servo motor (503), the two-position five-way solenoid valve (507) and the control module (7). The adaptive bistable module (6) is adjacent to the drive module (5).

3. The adaptive bistable flexible biomimetic robotic fish according to claim 2, characterized in that, The adaptive bistable module (6) includes a column (601), a triangular bracket (602), a slide rail (603), a front spring (604), a slider (605), a rear spring (606), a pull rod (607), and a limiting member (608). The column (601) is fixedly installed in the fish head compartment (101). The triangular bracket (602) is horizontally arranged on one side of the column (601). Two parallel slide rails (603) are arranged at the center of the triangular bracket (602). The slider (605) is slidably arranged in the two slide rails (603). The limiting member (608) is provided at the end of the rail (603) to prevent the slider (605) from coming out. One side of the slider (605) is connected to the column (601) through the front spring (604), and the other side of the slider (605) is connected to one end of the rear spring (606). The other end of the rear spring (606) passes through the flexible fish body (3) and is connected to the front end of the pull rod (607). The rear end of the pull rod (607) is fixed on the flexible tail fin (4). The front spring (604) and the rear spring (606) are always kept in a pre-stretched state.

4. The adaptive bistable flexible biomimetic robotic fish according to claim 3, characterized in that, The flexible fish body (3) has a split structure, consisting of a completely symmetrical left fish body and a right fish body. The left and right fish bodies are made of flexible material, allowing for repeated large-scale bending and deformation but not axial elongation. The structure of the right fish body is identical to that of the left fish body. The left fish body includes a semi-conical shell (301), a cavity cover (302), and a semi-conical cavity (303). The semi-conical shell (301) and the cavity cover (302) are integrally formed. The interior of the semi-conical shell (301) and the cavity cover (302) is the semi-conical cavity (303). Multiple longitudinally parallel semi-circular ribs (304) are fixedly arranged inside the semi-conical cavity (303). These semi-circular ribs (304) are evenly spaced, dividing the semi-conical cavity (303) into multiple chambers. The diameters of the multiple semicircular ribs (304) gradually decrease to match the inner diameter of the semiconical cavity (303). The cavity cover (302) is provided with a first hollowed-out arc groove (305). A second hollowed-out arc groove (306) is provided at the center of each semicircular rib (304). A liquid inlet / outlet (307) is provided near the first hollowed-out arc groove (305). A cavity communication hole (308) is provided near the second hollowed-out arc groove (306). The tail of the left side of the fish body is solid. A cavity outlet channel (309) is provided on the central axis of the tail of the left side of the fish body. The first hollowed-out arc groove (305), the second hollowed-out arc groove (306) and the cavity outlet channel (309) are located on the same straight line. The liquid inlet / outlet (307) is connected to the connecting pipe (508).

5. The adaptive bistable flexible biomimetic robotic fish according to claim 4, characterized in that, The flexible fish body (3) further includes a trapezoidal intermediate sealing cover plate (3010), which is positioned in the middle of the left and right sides of the fish body. The intermediate sealing cover plate (3010) is sealed to both the left and right sides of the fish body to prevent liquid leakage. An arc-shaped protrusion structure (3011) is provided on the central axis of the intermediate sealing cover plate (3010). The arc-shaped protrusion structure (3011) is connected to the first on both sides of the fish body. The hollowed-out arc groove (305) and the second hollowed-out arc groove (306) are structurally compatible and sealed together. The arc-shaped protrusion structure (3011) is hollow inside. The rear spring (606) passes through the interior of the arc-shaped protrusion structure (3011) and is connected to the front end of the pull rod (607). The front end of the pull rod (607) is fixed to the rear end of the arc-shaped protrusion structure (3011). The pull rod (607) is still placed in the chamber outlet channel (309).

6. The adaptive bistable flexible biomimetic robotic fish according to claim 1, characterized in that, The rigid fish head (1) is processed by 3D printing technology, and the flexible tail fin (4) is manufactured by injection molding.

7. The adaptive bistable flexible biomimetic robotic fish according to claim 1, characterized in that, The rigid fish head (1) and the flexible fish body (3) are fixedly connected by positioning pins and screws to ensure that the rigid fish head (1) and the flexible fish body (3) do not rotate relative to each other, and waterproof sealant is applied to the joint to prevent relative sliding and water leakage.

8. The adaptive bistable flexible biomimetic robotic fish according to claim 2, characterized in that, The control module (7) is used to control the start and stop, speed of the servo motor (503), and the potential of the two-position five-way solenoid valve (507), thereby controlling the swing frequency and swing amplitude of the flexible bionic robotic fish.

9. The adaptive bistable flexible biomimetic robotic fish according to claim 5, characterized in that, The flexible fish body (3) and the flexible tail fin (4) are both made of polymer flexible material and are fixedly connected by positioning pins and screws; the intermediate sealing cover plate (3010) is formed by casting colloid and fiber cloth together, which can be repeatedly bent but cannot be stretched axially.

10. An adaptive bistable flexible biomimetic robotic fish according to claim 5, characterized in that, The internal space of the arc-shaped protrusion structure (3011) is appropriate, and during the swimming process of the flexible bionic robotic fish, the rear spring (606) and the arc-shaped protrusion structure (3011) never come into contact, thus avoiding mutual interference.

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