A multi-joint flexible robotic fish based on air pressure driving and a working method thereof

Abstract

This invention belongs to the field of underwater biomimetic robotics, specifically relating to a pneumatically driven multi-joint flexible robotic fish and its operating method. This invention uses air pressure as a power source, employing a reversing valve to precisely control the inflation and deflation of the left and right flexible pneumatic muscle modules, driving multiple fish-rib joints to sequentially link and achieve flexible oscillation of the robotic fish. Furthermore, the swimming speed and turning movements of the robotic fish can be controlled by adjusting the actuation frequency and timing of the reversing valve. Compared to traditional rigid-joint robotic fish, this invention offers advantages such as low underwater noise, strong collision avoidance, and swimming posture more closely resembling that of real fish. Simultaneously, the multi-joint structure significantly improves the underwater maneuverability and propulsion efficiency of the robotic fish, solving the technical problems of existing pneumatically driven flexible robotic fish with a limited number of joints and insufficient motion control precision. It has broad application prospects in underwater exploration, marine environmental monitoring, and small-scale underwater operations.

Description

Technical Field

[0001] This invention belongs to the field of underwater biomimetic robot technology, specifically relating to a multi-joint flexible robotic fish based on air pressure drive and its working method. Background Technology

[0002] Natural selection has shaped the efficient underwater movement structure and locomotion patterns of fish, whose flexible body undulations give them high propulsion efficiency, strong maneuverability, and low noise. Biomimetic robotic fish, as underwater robots that mimic fish swimming, have significant advantages over traditional propeller-driven underwater devices in terms of adaptability to complex underwater environments and friendliness to marine life, making them a research hotspot in the field of underwater robotics.

[0003] Currently, the driving methods for biomimetic robotic fish are mainly divided into two categories: rigid motor drive and flexible pressure drive. Rigid motor-driven robotic fish achieve oscillation by using a motor to drive rigid joints. Although the structural design and control logic are relatively simple, they suffer from problems such as high underwater noise, poor collision avoidance, and significant deviations in swimming posture from real fish. Furthermore, mechanical wear of rigid joints easily leads to increased failure rates, making them unsuitable for complex underwater operating environments. With the development of materials science and intelligent drive technology, flexible pressure drive methods such as pneumatic and hydraulic pressure are widely used in the research and development of biomimetic robotic fish. Flexible drive robotic fish, with their compliant body structure, effectively solve the aforementioned shortcomings of rigid drive robotic fish, becoming an important development direction in this field.

[0004] In pressure-driven flexible biomimetic robotic fish, pneumatic actuation has attracted researchers' attention due to its convenient power source integration and lightweight system structure. However, existing pneumatic flexible robotic fish still face several technical bottlenecks: most products use single-joint or double-joint structures, and the limited number of joints results in insufficient underwater maneuverability, making it difficult to perform complex turning, obstacle avoidance, and other maneuvers; the poor integration of reversing and pressure control components in some pneumatic actuation systems leads to low motion control precision, making it impossible to accurately adjust swimming speed and swing amplitude; at the same time, the design of the connection structure between the drive unit and the skeleton in some pneumatic flexible robotic fish is unreasonable, resulting in low power transmission efficiency and affecting the improvement of propulsion performance.

[0005] Furthermore, the tuning of control parameters for existing pneumatically driven robotic fish primarily relies on empirical trial-and-error methods. Due to the nonlinear hysteresis characteristics of pneumatic muscles, the complex coupling relationship between inflation frequency, joint phase difference, and swimming speed, coupled with the fluid-structure interaction effect in the underwater environment, traditional physical model-based parameter optimization methods are difficult to apply. Operators often need to conduct numerous repeated experiments to determine an optimal combination of control parameters, which is not only inefficient but also makes it difficult to guarantee finding the global optimum. Therefore, a systematic method is urgently needed that can accurately establish the mapping relationship between control parameters and swimming performance and automatically solve for the optimal control parameters.

[0006] A similar technical solution to this invention is a biomimetic fish system based on hybrid pneumatic muscles disclosed in patent number CN108393868A. However, this invention differs significantly from CN108393868A. The technical solution disclosed in CN108393868A employs a hybrid pneumatic muscle layout, using multiple independent pneumatic muscles to drive single-joint movements. The fish skeleton consists of a spine + The simple structure of the connecting plate, with the drive unit and the frame being rotatably hinged, achieves simple swinging only through the on / off switching of pneumatic muscles, lacking dedicated air pressure control timing logic and specific design for the number and arrangement of muscle groups. In contrast, this invention adopts a three-joint series drive structure, forming an integrated frame with rigid-flexible coupling through the fish ribs and the neutral plate of the fish body. The drive unit is rigidly fixed to the fish ribs via the connecting body, and is equipped with independent two-position four-way electromagnetic reversing valves on the left and right to precisely control the on / off switching and timing of air pressure. The number of muscle groups in different joints is designed differently, and the swimming speed and steering are precisely controlled by adjusting the actuation frequency of the reversing valves. The fish head integrates an integrated air cylinder power source and servo control components, realizing the integration of the air pressure system and the refinement of motion control. Summary of the Invention

[0007] The purpose of this invention is to address the technical pain points of existing pneumatic flexible robotic fish, such as the limited number of joints, insufficient motion control precision, and low power transmission efficiency, by providing a pneumatically driven multi-joint flexible robotic fish and its working method.

[0008] A pneumatically driven, multi-jointed flexible robotic fish, comprising a head, body, and tail.

[0009] The fish head is equipped with a gas cylinder and multiple reversing valves, and the output end of the gas cylinder is connected to each of the reversing valves respectively.

[0010] The fish body includes multiple rib joints, each rib joint including two ribs and a flexible pneumatic muscle module connecting the two ribs, with adjacent rib joints sharing the ribs at their junctions.

[0011] The flexible pneumatic muscle module includes a first connector, a pressure chamber, a flexible muscle actuator, and a second connector. The pressure chamber has air vents at both ends and a piston inside. One end of the flexible muscle actuator is connected to the second connector, and the other end communicates with the interior of the pressure chamber and is located on one side of the piston. The other side of the piston is connected to the first connector. The first and second connectors are respectively connected to the two ribs of the fish rib joint where the flexible pneumatic muscle module is located. All air vents of the flexible pneumatic muscle modules on the same side of the same fish rib joint are connected to the same reversing valve inside the fish head via pipelines.

[0012] Furthermore, when the reversing valves of all flexible pneumatic muscle modules on the left side of a certain fish rib joint are switched to the inflation state, and the reversing valves of all flexible pneumatic muscle modules on the right side of the same fish rib joint are switched to the deflation state, the gas cylinder inflates the pressure chambers of all flexible pneumatic muscle modules on the left side of the fish rib joint through the pipeline. Under the action of air pressure, the flexible muscle actuators of all flexible pneumatic muscle modules on the left side contract and widen, thereby causing the fish rib joint to bend to the left and generate displacement. Under the action of structural constraint, the first connector of all flexible pneumatic muscle modules on the right side of the fish rib joint drives the piston to move, and the displacement caused by the left bending of the fish rib joint is compensated by deflation.

[0013] Furthermore, the fish rib is annular, and all flexible pneumatic muscle modules in the fish rib joint are evenly arranged around the annular fish rib; the fish body is provided with a fish body neutral plate, and the fish ribs of all fish rib joints are fitted on the fish body neutral plate.

[0014] Furthermore, the front end of the first connector and the rear end of the second connector are provided with lugs for connecting to the fish rib.

[0015] Furthermore, the fish head has a neutral surface, and the gas cylinder and all reversing valves are installed on the neutral surface of the fish head.

[0016] A method for operating a pneumatically driven, multi-jointed flexible robotic fish includes the following:

[0017] The fish body includes Each of the fish's rib joints is numbered sequentially from head to tail.

[0018] Set inflation frequency Phase difference with joint This allows for the determination of the inflation cycle. 1. Duration of unilateral inflation Delay time between adjacent fish rib joints ;

[0019] In an inflation cycle within, within At any moment, control the first The reversing valves of all flexible pneumatic muscle modules on the left side of the fishbone joint are switched to the inflation state, while simultaneously controlling the first... The reversing valves of all flexible pneumatic muscle modules on the right side of the fishbone joint are switched to the venting state; in At any moment, control the first The reversing valves of all flexible pneumatic muscle modules on the left side of the fishbone joint switch to the venting state, while simultaneously controlling the first... The reversing valves of all flexible pneumatic muscle modules on the right side of the fish rib joint are switched to the inflation state.

[0020] By making the rib joints of the robotic fish bend and move in sequence, a continuous traveling wave propulsion is formed.

[0021] Furthermore, a forward neural network model is constructed and trained to control the inflation frequency. Phase difference with joint The steady-state swimming speed and power consumption of the robotic fish are used as model inputs and model outputs.

[0022] Based on a trained neural network forward model, and according to the target steady-state swimming speed of the robotic fish, the optimal inflation frequency with the lowest power consumption is obtained through optimization. Phase difference with joint .

[0023] A computer device includes a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the above-described method for operating a pneumatically driven multi-jointed flexible robotic fish.

[0024] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method for operating a pneumatically driven, multi-jointed flexible robotic fish.

[0025] A computer program product includes computer instructions that, when executed by a processor, implement the steps of the above-described method for operating a pneumatically driven, multi-jointed flexible robotic fish.

[0026] The beneficial effects of this invention are as follows:

[0027] This invention uses air pressure as a power source and employs a reversing valve to precisely control the inflation and deflation of the flexible pneumatic muscle modules on both sides. This drives multiple fish-rib joints to move in sequence, achieving flexible oscillation of the robotic fish. Furthermore, the swimming speed and turning movements of the robotic fish can be controlled by adjusting the actuation frequency and timing of the reversing valve. Compared to traditional rigid-jointed robotic fish, this invention has the advantages of low underwater noise, strong collision avoidance, and swimming posture that is closer to that of real fish. At the same time, the multi-joint structure significantly improves the underwater maneuverability and propulsion efficiency of the robotic fish, solving the technical problems of the limited number of joints and insufficient motion control precision in existing pneumatic flexible robotic fish. It has broad application prospects in underwater exploration, marine environmental monitoring, and small-scale underwater operations. Attached Figure Description

[0028] Figure 1 This is a cross-sectional view of a fish head in one embodiment of the present invention.

[0029] Figure 2 This is an exploded view of the fish body and tail in one embodiment of the present invention.

[0030] Figure 3This is an overall view of a flexible pneumatic muscle module in one embodiment of the present invention.

[0031] Figure 4 This is an exploded view of a flexible pneumatic muscle module in one embodiment of the present invention.

[0032] Figure 5 This is a cross-sectional view of a flexible pneumatic muscle module in one embodiment of the present invention.

[0033] Figure 6 This is a schematic diagram illustrating the deformation principle of the fish rib joint bending to the left in one embodiment of the present invention.

[0034] Figure 7 This is a schematic diagram illustrating the deformation principle of the fish rib joint bending to the right in one embodiment of the present invention. Detailed Implementation

[0035] The present invention will now be further described with reference to the accompanying drawings.

[0036] This invention provides a pneumatically driven, multi-jointed flexible robotic fish, comprising a head, body, and tail. The head contains an air cylinder 1-3 and multiple reversing valves, with the output ends of the air cylinder 1-3 connected to each reversing valve. A neutral surface 1-6 is located within the head, on which the air cylinder 1-3 and all reversing valves are mounted. The body includes multiple rib joints, each consisting of two ribs and a flexible pneumatic muscle module connecting the two ribs. Adjacent rib joints share a common rib at their junction. The ribs are annular, and all flexible pneumatic muscle modules within the rib joints are evenly arranged around the annular ribs. A neutral plate 2-3 is located within the body, on which the ribs of all rib joints are fitted.

[0037] like Figure 3 , Figure 4 and Figure 5 As shown, the flexible pneumatic muscle module includes a first connector 4-1, a pressure chamber, a flexible muscle actuator 4-5, and a second connector 4-6; the pressure chamber includes an air exchange cover 4-2 and a rigid shell 4-3.

[0038] Air exchange ports are provided at both ends of the pressure chamber, and a piston 4-4 is provided inside the pressure chamber; one end of the flexible muscle actuator 4-5 is connected to the second connector 4-6, and the other end is connected to the inside of the pressure chamber and located on one side of the piston 4-4. The other side of the piston 4-4 is connected to the first connector 4-1; the first connector 4-1 and the second connector 4-6 are respectively connected to the two fish ribs of the fish rib joint where the flexible pneumatic muscle module is located; the air exchange ports of all flexible pneumatic muscle modules on the same side of the same fish rib joint are connected to the same reversing valve inside the fish head through pipelines; the front end of the first connector 4-1 and the rear end of the second connector 4-6 are provided with lifting lugs for connecting to the fish ribs.

[0039] like Figure 6 As shown, when the reversing valves of all flexible pneumatic muscle modules on the left side of a certain fish rib joint are switched to the inflation state, and at the same time the reversing valves of all flexible pneumatic muscle modules on the right side of the same fish rib joint are switched to the deflation state, the gas cylinder 1-3 inflates the pressure chambers of all flexible pneumatic muscle modules on the left side of the fish rib joint through the pipeline. Under the action of air pressure, the flexible muscle actuators 4-5 of all flexible pneumatic muscle modules on the left side contract and widen, thereby causing the fish rib joint to bend to the left and generate displacement. Under the action of structural constraint, the first connector 4-1 of all flexible pneumatic muscle modules on the right side of the fish rib joint drives the piston 4-4 to move, and the displacement caused by the left bending of the fish rib joint is compensated by deflation.

[0040] Similarly, such as Figure 7 As shown, when the reversing valves of all flexible pneumatic muscle modules on the left side of a certain fish rib joint are switched to the deflation state, and at the same time the reversing valves of all flexible pneumatic muscle modules on the right side of the same fish rib joint are switched to the inflation state, the gas cylinder 1-3 inflates the air chambers of all flexible pneumatic muscle modules on the right side of the fish rib joint through the pipeline. Under the action of air pressure, the flexible muscle actuators 4-5 of all flexible pneumatic muscle modules on the right side contract and widen, thereby causing the fish rib joint to bend to the right and generate displacement. Under the action of structural constraint, the first connector 4-1 of all flexible pneumatic muscle modules on the left side of the fish rib joint drives the piston 4-4 to move, and the displacement caused by the rightward bending of the fish rib joint is compensated by deflation.

[0041] Example 1:

[0042] In this embodiment, the body of the pneumatically driven multi-joint flexible robotic fish consists of three rib joints.

[0043] like Figure 1 As shown, the fish head contains six reversing valves: a left reversing valve 1-4-1 for the first joint, a right reversing valve 1-4-2 for the first joint, a left reversing valve 1-4-3 for the second joint, a right reversing valve 1-4-4 for the second joint, a left reversing valve 1-4-5 for the third joint, and a right reversing valve 1-4-6 for the third joint. The fish head shell 1-1 is mounted on the front side of the neutral surface 1-6 of the fish head. The gas cylinder 1-3 is mounted on the upper part of the neutral surface 1-6 of the fish head via a gas cylinder fixing bracket 1-2. All the reversing valves are sequentially mounted on the lower part of the neutral surface 1-6 of the fish head. It also includes a left servo motor 1-5-1 and a right servo motor 1-5-2 for driving the reversing valves.

[0044] like Figure 2As shown, the three rib joints of the fish body include the first rib 2-1-1, the second rib 2-1-2, the third rib 2-1-3, the fourth rib 2-1-4, the first joint muscle group 2-2-1, the second joint muscle group 2-2-3, and the third joint muscle group 2-2-3. The first rib 2-1-1 connects to the neutral surface 1-6 of the fish head. The second ribs 2-1-2 and the third rib 2-1-3 are mounted on the neutral plate 2-3 of the fish body. The rear side of the fourth rib 2-1-4 connects to the tail 2-4. The anterior side of the first joint muscle group 2-2-1 connects to the first rib 2-1-1, and the posterior side connects to the second rib 2-1-2. The anterior side of the second joint muscle group 2-2-2 connects to the second rib 2-1-2, and the posterior side connects to the third rib 2-1-3. The anterior side of the third joint muscle group 2-2-3 connects to the third fish rib 2-1-3, and the posterior side connects to the fourth fish rib 2-1-4.

[0045] The robotic fish works as follows: Flexible pneumatic muscle modules are evenly distributed between the ribs, providing contractile force for joint movement. Six independent two-position four-way electromagnetic reversing valves are installed above the neutral surface 1-6 of the fish head, all powered by air cylinder 1-3, controlling the inflation and deflation of the flexible muscle actuators. In the initial state, all six reversing valves are connected to the outside, piston 4-4 is at the bottom of the pressure chamber, the neutral plate 2-3 of the fish body remains straight, and the tail does not swing or bend.

[0046] Compared to the overall synchronous deflection achieved by a single-joint mechanism, the three-joint flexible robotic fish proposed in this embodiment enables each joint to move in sequence and bend segment by segment, forming a continuous undulating curve, with a posture height closely resembling that of a real fish. The first and second joint muscle groups each contain six muscle groups, while the third joint muscle group contains four muscle groups. Through differentiated design, the problems of the limited number of joints and insufficient motion control precision in existing pneumatic flexible robotic fish are solved, significantly improving underwater maneuverability and propulsion efficiency.

[0047] In terms of air pressure control, six independent two-position four-way solenoid directional valves are installed above the neutral surface of the fish head. All valves are powered by air cylinders. By adjusting the actuation frequency and timing of these valves, inflation and deflation can be precisely controlled, thereby regulating swimming speed and turning movements. Compared to the hybrid layout in CN108393868A, which only achieves simple oscillation through the on / off switching of pneumatic muscles, this embodiment offers superior integrated arrangement and precise control capabilities.

[0048] Example 2:

[0049] To fully leverage the freedom advantages of the multi-joint series structure of this invention, a working method for a pneumatically driven multi-joint flexible robotic fish is designed. By independently controlling the actuation sequence and state of each reversing valve, it can efficiently propel and oscillate in a traveling wave pattern. Compared to the overall synchronous deflection achieved by a single-joint mechanism, the multi-joint linkage and segmented bending form a continuous undulating curve, resulting in a posture and height closely resembling that of a real fish, exhibiting smoothness and naturalness.

[0050] The fish body includes Each of the fish's rib joints is numbered sequentially from head to tail.

[0051] Set inflation frequency Phase difference with joint This allows for the determination of the inflation cycle. 1. Duration of unilateral inflation Delay time between adjacent fish rib joints ;

[0052] In an inflation cycle within, within At any moment, control the first The reversing valves of all flexible pneumatic muscle modules on the left side of the fishbone joint are switched to the inflation state, while simultaneously controlling the first... The reversing valves of all flexible pneumatic muscle modules on the right side of the fishbone joint are switched to the venting state; in At any moment, control the first The reversing valves of all flexible pneumatic muscle modules on the left side of the fishbone joint switch to the venting state, while simultaneously controlling the first... The reversing valves of all flexible pneumatic muscle modules on the right side of the fish rib joint are switched to the inflation state.

[0053] By making the rib joints of the robotic fish bend and move in sequence, a continuous traveling wave propulsion is formed.

[0054] Inflation frequency can be controlled by constructing and training a positive neural network model. Phase difference with joint The steady-state swimming speed and power consumption of the robotic fish are used as model inputs and model outputs.

[0055] Based on a trained neural network forward model, and according to the target steady-state swimming speed of the robotic fish, the optimal inflation frequency with the lowest power consumption is obtained through optimization. Phase difference with joint .

[0056] Compared to traditional control parameter tuning methods that rely on empirical trial and error or simplified physical models, the control parameter optimization method based on neural networks and random sampling proposed in this embodiment has the following significant advantages:

[0057] First, this method fully considers the nonlinear hysteresis characteristics of the flexible muscle actuator in the pneumatic drive system and the complex influence of fluid-structure interaction on swimming speed and power consumption in the underwater environment. By constructing a fully connected feedforward neural network, a high-precision nonlinear mapping model between inflation frequency, joint phase difference and steady-state swimming speed and power consumption is established, overcoming the shortcomings of traditional physical models in accurately describing this type of nonlinear relationship.

[0058] Secondly, a two-stage optimization strategy combining large-scale uniform random sampling and neighborhood random sampling is adopted. This strategy can not only search extensively in the global parameter space and avoid getting trapped in local optima, but also finely locate the optimal solution in the neighborhood of the candidate solution. This significantly improves the solution accuracy and convergence efficiency of the power consumption minimization problem under the desired speed constraint, and solves the problem that existing methods are difficult to systematically optimize due to the complexity of the parameter space.

[0059] Finally, given the desired swimming speed, this method solves for the corresponding optimal inflation frequency and optimal phase difference through a neural network and a random sampling strategy. The results can be converted into the action timing of the electromagnetic reversing valves of each joint, avoiding the inefficiency of repeated manual experiments and debugging. While ensuring the accuracy of swimming speed, it also takes into account the swimming performance and energy economy of the robotic fish, providing a reliable control scheme for the efficient and energy-saving operation of pneumatically driven robotic fish in long-term underwater operations.

[0060] Example 3:

[0061] To further improve the propulsion performance of the robotic fish, this embodiment provides a control parameter optimization method based on neural networks and random algorithms to solve for the optimal inflation frequency and optimal phase difference that maximize the swimming speed of the robotic fish.

[0062] Inflation frequency is defined as the switching frequency of the reversing valves of each joint, that is, the number of times a single muscle group is inflated per second, with a value ranging from 1 to 5 Hz. Phase difference is defined as the electrical signal delay angle between the actions of the reversing valves of adjacent joints, with a value ranging from 0° to 180°. A complete left-right reciprocating swimming cycle consists of two inflation actions, that is, one inflation on the left side and one inflation on the right side.

[0063] Step S1: Neural network motion modeling;

[0064] A fully connected feedforward neural network was used to establish a mapping model between control parameters and swimming speed. The network input layer is a two-dimensional vector, corresponding to the inflation frequency and phase difference, respectively; the output layer is a one-dimensional vector, corresponding to the steady-state swimming speed; it contains two hidden layers with 18 and 12 neurons respectively, and the Tansig function is used as the activation function. The network fitting function is expressed as follows: , The steady-state swimming speed of the robotic fish Let be the nonlinear mapping function represented by the trained neural network.

[0065] Training data was acquired as follows: A visual acquisition platform was built in a still water environment. 400 combinations of inflation frequencies and phase differences were randomly generated to drive the robotic fish to swim, and the steady-state swimming speed was recorded by a camera. The acquired data was divided into training, validation, and test sets in a 7:2:1 ratio. Mean squared error was used as the loss function, and the Levenberg-Marquardt algorithm was used for training, with a maximum of 1000 iterations and a target mean squared error not exceeding [a certain value]. After training, the coefficient of determination of the neural network model on the test set should be no less than 0.92.

[0066] Step S2: Speed ​​maximization algorithm based on random sampling;

[0067] Because neural networks are highly nonlinear black-box models, their maximum values ​​cannot be directly solved analytically.

[0068] This embodiment employs a strategy combining large-scale random sampling and neighborhood random sampling to solve for the optimal control parameters. The algorithm consists of two stages: the first stage performs large-scale uniform random sampling across the entire parameter space to avoid getting trapped in local optima; the second stage performs random sampling within the neighborhood of the discovered optimal candidate solution to accurately locate the peak position.

[0069] The first phase extensively explores the entire parameter space through 50,000 uniform random samples, ensuring high-probability coverage of the region containing the global optimum. The second phase further refines the peak location by performing 1,000 random samples within the neighborhood of the optimum, with the frequency sampling range set to the candidate solutions. The phase sampling range is set as the candidate solution. To balance search accuracy and efficiency.

[0070] Step S3: Conversion of optimal control parameters to timing parameters

[0071] The optimal inflation frequency output by the solver and optimal phase difference This is converted into the specific action sequence of the electromagnetic directional valve.

[0072] The feasibility of this embodiment can be verified by the following method: setting the optimal control parameters output by Algorithm 1 into the robotic fish control system and measuring its steady-state swimming speed in still water; conducting comparative experiments by adjusting the inflation frequency and phase difference near the optimal parameters and observing the speed change trend. The verification results confirm that the parameter combination is indeed the speed extremum point in the current parameter space.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-joint flexible robotic fish driven by air pressure, characterized in that: Including the fish head, body, and tail. The fish head is equipped with an air cylinder (1-3) and multiple reversing valves, and the output end of the air cylinder (1-3) is connected to each reversing valve respectively; The fish body includes multiple rib joints, each rib joint including two ribs and a flexible pneumatic muscle module connecting the two ribs, with adjacent rib joints sharing the ribs at their junctions. The flexible pneumatic muscle module includes a first connector (4-1), a pressure chamber, a flexible muscle actuator (4-5), and a second connector (4-6). The pressure chamber has air vents at both ends and a piston (4-4) inside. One end of the flexible muscle actuator (4-5) is connected to the second connector (4-6), and the other end communicates with the interior of the pressure chamber and is located on one side of the piston (4-4). The other side of the piston (4-4) is connected to the first connector (4-1). The first connector (4-1) and the second connector (4-6) are respectively connected to the two ribs of the fish rib joint where the flexible pneumatic muscle module is located. The air vents of all flexible pneumatic muscle modules on the same side of the same fish rib joint are connected to the same reversing valve inside the fish head via pipelines. When the reversing valves of all flexible pneumatic muscle modules on the left side of a certain fish rib joint are switched to the inflation state, and the reversing valves of all flexible pneumatic muscle modules on the right side of the same fish rib joint are switched to the deflation state, the gas cylinder (1-3) inflates the pressure chambers of all flexible pneumatic muscle modules on the left side of the fish rib joint through the pipeline. Under the action of air pressure, the flexible muscle actuators (4-5) of all flexible pneumatic muscle modules on the left side contract and widen, thereby causing the fish rib joint to bend to the left and generate displacement. Under the action of structural constraint, the first connector (4-1) of all flexible pneumatic muscle modules on the right side of the fish rib joint drives the piston (4-4) to move, and the displacement caused by the left bending of the fish rib joint is compensated by deflation. The fish rib is annular, and all flexible pneumatic muscle modules in the fish rib joint are evenly arranged around the annular fish rib. The working method of the pneumatically driven multi-joint flexible robotic fish specifically includes: The fish body comprises a fish rib joint, sequentially numbered from the fish head to the fish tail; Set inflation frequency Phase difference with joint This allows for the determination of the inflation cycle.

1. Duration of unilateral inflation Delay time between adjacent fish rib joints ; In an inflation cycle within, within At any moment, control the first The reversing valves of all flexible pneumatic muscle modules on the left side of the fishbone joint are switched to the inflation state, while simultaneously controlling the first... The reversing valves of all flexible pneumatic muscle modules on the right side of the fishbone joint are switched to the venting state; in At any moment, control the first The reversing valves of all flexible pneumatic muscle modules on the left side of the fishbone joint are switched to the venting state, while simultaneously controlling the first... The reversing valves of all flexible pneumatic muscle modules on the right side of the fish rib joint are switched to the inflation state. By making the rib joints of the robotic fish bend and move in sequence, a continuous traveling wave propulsion is formed. Build and train a neural network forward model to control the inflation frequency. Phase difference with joint The steady-state swimming speed and power consumption of the robotic fish are used as model inputs and model outputs. Based on a trained neural network forward model, and according to the target steady-state swimming speed of the robotic fish, the optimal inflation frequency with the lowest power consumption is obtained through optimization. Phase difference with joint .

2. The multi-joint flexible robotic fish driven by air pressure according to claim 1, wherein: The front end of the first connector (4-1) and the rear end of the second connector (4-6) are provided with lugs for connecting with the fish rib.

3. The multi-joint flexible robotic fish driven by air pressure according to claim 1, wherein: The fish head is provided with a neutral surface (1-6), and the gas cylinder (1-3) and all the reversing valves are installed on the neutral surface (1-6). The fish body is provided with a neutral plate (2-3), the front side of the first fish rib joint is connected to the neutral surface (1-6), the rear side of the last fish rib joint is connected to the tail, and the ribs of the remaining fish rib joints are installed on the neutral plate (2-3).

4. A computer device, comprising a memory, a processor, and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 3.

5. A computer readable storage medium having stored thereon a computer program, characterized in that: When executed by a processor, the computer program implements the steps of the method according to any one of claims 1 to 3.

6. A computer program product comprising computer instructions, characterized in that: When executed by a processor, the computer instructions implement the steps of the method according to any one of claims 1 to 3.

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