WO2023050582A1

WO2023050582A1 - Angle of attack-based bionic robotic fish fixed-depth control method and apparatus

Info

Publication number: WO2023050582A1
Application number: PCT/CN2021/137578
Authority: WO
Inventors: 耿永清; 左启阳; 何凯
Original assignee: 深圳先进技术研究院
Priority date: 2021-09-28
Filing date: 2021-12-13
Publication date: 2023-04-06
Also published as: CN113734393A; CN113734393B

Abstract

An angle of attack-based bionic robotic fish fixed-depth control method and apparatus. If a first depth does not fall within a preset depth range, an actual pectoral fin angle of attack at a current moment is determined according to the pitch angle of a bionic robotic fish acquired by an inertial sensor and a first deflection angle of the pectoral fin at a previous moment; the first deflection angle is adjusted to a second deflection angle according to the actual pectoral fin angle of attack and a first expected pectoral fin angle of attack, so that the bionic robotic fish moves to the preset depth range by means of a floating movement or a diving movement; the bionic robotic fish adjusts a fourth deflection angle of the pectoral fin according to a second depth acquired by a depth sensor and a preset depth during the movement of the bionic robotic fish within the preset depth range, so as to achieve the fixed-depth cruise. The method is simple in adjustment process and good in real-time performance.

Description

Depth control method and device for bionic robotic fish based on angle of attack method

technical field

The present application relates to the technical field of robotic fish control, in particular to a method and device for controlling the depth of a bionic robotic fish based on an angle of attack method.

Background technique

The bionic robot fish is a kind of underwater mobile robot, which has the advantages of high propulsion efficiency, strong maneuverability, and good concealment performance. It has been widely used in underwater operations in complex environments such as seabed survey, military reconnaissance, marine biological research, and water quality monitoring. . Depth control is one of the basic capabilities required for the bionic robotic fish to complete underwater operations, including floating control, diving control and cruise control. Existing depth control methods include shape change method, water storage bin method, center of gravity adjustment method, etc. These methods require the bionic robot fish to adjust its own structure or adjust its volume by absorbing and releasing water to achieve depth control. The adjustment process is cumbersome, resulting in The real-time performance of the method is poor.

Contents of the invention

The present application provides a bionic robotic fish depth control method and device based on an angle of attack method, which can solve the problems of cumbersome adjustment process and poor real-time performance of the existing bionic robotic fish depth control method.

In the first aspect, the embodiment of the present application provides a method for controlling the depth of a bionic robotic fish based on the angle of attack method, the method comprising:

When the first depth of the bionic robotic fish at the current moment is not within the preset depth range, obtain the pitch angle of the bionic robotic fish at the current moment, and the first deflection angle of the pectoral fin of the bionic robotic fish at the previous moment; according to the first deflection The angle and pitch angle determine the actual pectoral fin attack angle of the bionic robot fish at the current moment; according to the relative positional relationship between the first depth and the preset depth range, the first expected pectoral fin attack angle is determined, and the first expected pectoral fin attack angle is used to make the bionic machine The pitching moment of the fish is greater than or equal to the first threshold; the first deflection angle is adjusted to the second deflection angle according to the actual pectoral fin attack angle and the first expected pectoral fin attack angle, so that the bionic robotic fish moves to a preset depth range;

When the bionic robotic fish moves from the first depth to the boundary of the preset depth range, both the first expected pectoral fin attack angle and the third pectoral fin deflection angle are adjusted to 0, and then, the bionic robotic fish moves within the preset depth range , adjusting the fourth deflection angle of the pectoral fin at the current moment according to the second depth of the bionic robotic fish at the current moment and the preset depth, and the preset depth is within the preset depth range.

Based on the depth determination control method for the bionic robotic fish provided in the present application, it can be determined whether the bionic robotic fish should dive or float up according to the relative positional relationship between the first depth and the preset depth range. Determine the actual pectoral fin attack angle of the bionic robot fish at the current moment according to the pitch angle at the current moment and the first deflection angle of the pectoral fin at the previous moment, and the first deflection angle can be adjusted by using the actual pectoral fin attack angle and the first expected pectoral fin attack angle . Through the real-time adjustment of the pectoral fin deflection angle, the pitch angle and motion direction of the bionic robotic fish can be adjusted, and then the actual pectoral fin angle of attack can be adjusted to approach the first desired pectoral fin angle of attack, so that the bionic robotic fish can produce a larger The pitching moment shortens the path of the bionic robotic fish moving from the first depth to the preset depth range, reduces the time between the bionic robotic fish from the first depth to the preset depth range, and improves the real-time performance of the depth-fixed control method.

Optionally, adjusting the first deflection angle to the second deflection angle according to the actual pectoral fin attack angle and the first expected pectoral fin attack angle includes: determining the difference between the pectoral fin attack angle error and the pectoral fin attack angle Angle error change rate; use the preset first fuzzy control table corresponding to the relative position relationship to perform fuzzy control on the pectoral fin angle of attack error and pectoral fin angle of attack error change rate to obtain the actual control increment; according to the actual control increment The first deflection angle is adjusted to obtain the second deflection angle of the pectoral fin at the current moment.

Based on the above optional method, during the motion of the bionic robotic fish, the actual angle of attack of the pectoral fins will be affected by factors such as the surrounding water flow and motion posture. Using the advantages of fuzzy control algorithm in dealing with nonlinear control and uncertainty, the pectoral fin angle of attack error between the actual pectoral fin angle of attack and the first expected pectoral fin angle of attack and the rate of change of pectoral fin angle of attack error are processed, and the actual control gain is obtained. to adjust the first deflection angle in real time, which can improve the accuracy of the depth control of the bionic robotic fish.

Optionally, the pitching moment includes pitching moment and pitching moment; if the first depth is less than the minimum value of the preset depth range, the first expected pectoral fin attack angle is used to make the pitching moment of the bionic robotic fish greater than or equal to the first threshold, the first A fuzzy control table is a diving fuzzy control table used to control the bionic robotic fish to dive; if the first depth is greater than the maximum value of the preset depth range, the first expected pectoral fin attack angle is used to make the bionic robotic fish look up. The torque is greater than or equal to the first threshold, and the first fuzzy control table is a floating fuzzy control table used to control the bionic robotic fish to perform floating movement.

Optionally, adjusting the fourth deflection angle of the pectoral fin at the current moment according to the second depth and the preset depth of the bionic robotic fish at the current moment includes: determining the difference between the depth error and the preset depth of the bionic robotic fish at the second depth at the current moment and the preset depth Depth error change rate: use the preset second fuzzy control table to perform fuzzy control processing on the depth error and the depth error change rate to obtain the fourth deflection angle of the pectoral fin at the current moment.

Optionally, the fixed depth control method also includes: during the bionic robotic fish moves from the first depth to the preset depth range, adjusting the swing frequency and swing amplitude of the tail fin of the bionic robotic fish, and setting the moving speed of the bionic robotic fish to the first Speed: During the movement of the bionic robotic fish within the preset depth range, the first speed is adjusted to a second speed, and the second speed is lower than the first speed.

Based on the above optional method, the swing frequency and swing amplitude of the tail fin will affect the movement speed of the bionic robot fish. The periodic swing of the tail fin can provide thrust for the bionic robot fish, and the coordinated propulsion of the tail fin and pectoral fin can make the bionic robot fish move quickly. Movement from a first depth to a preset depth range.

In the second aspect, the embodiment of the present application provides a bionic robotic fish depth-fixing control device based on the angle of attack method, which includes:

The acquiring unit is used to acquire the pitch angle of the bionic robotic fish at the current moment and the first deflection angle of the pectoral fin of the bionic robotic fish at the previous moment when the first depth of the bionic robotic fish at the current moment is not within the preset depth range ;

The control unit is used to determine the actual pectoral fin attack angle of the bionic robotic fish at the current moment according to the first deflection angle and pitch angle, and determine the first expected pectoral fin attack angle according to the relative positional relationship between the first depth and the preset depth range, the first The expected pectoral fin attack angle is used to make the pitching moment of the bionic robotic fish greater than or equal to the first threshold, and the first deflection angle is adjusted to the second deflection angle according to the actual pectoral fin attack angle and the first expected pectoral fin attack angle, so that the bionic robotic fish will Preset depth range movement; when the bionic robotic fish moves from the first depth to the boundary of the preset depth range, both the first expected pectoral fin attack angle and the third pectoral fin deflection angle are adjusted to 0, and then the bionic robotic fish During movement within the preset depth range, the fourth deflection angle of the pectoral fins at the current moment is adjusted according to the second depth of the bionic robotic fish at the current moment and the preset depth, and the preset depth is within the preset depth range.

Optionally, adjusting the first deflection angle to the second deflection angle according to the actual pectoral fin attack angle and the first expected pectoral fin attack angle includes: determining the difference between the pectoral fin attack angle error and the pectoral fin attack angle Angle error rate of change; Utilize the preset first fuzzy control table corresponding to the relative positional relationship to carry out fuzzy control processing on pectoral fin angle of attack error and pectoral fin angle of attack error rate of change to obtain actual control increment; according to actual control increment The first deflection angle is adjusted to obtain the second deflection angle of the pectoral fin at the current moment.

In a third aspect, an embodiment of the present application provides a computer-readable storage medium, where a computer program is stored in the computer-readable storage medium, and when the computer program is executed by a processor, the method according to any one of the above-mentioned first aspects is implemented.

In a fourth aspect, an embodiment of the present application provides a computer program product, which, when the computer program product is run on a terminal device, causes the terminal device to execute the method in any one of the foregoing first aspects.

In the fifth aspect, the embodiment of the present application provides a bionic robotic fish. The bionic robotic fish includes: a fish body, a caudal fin arranged on the fish body, and pectoral fins symmetrically arranged on both sides of the fish body. A processor, a rudder machine driver, pull-wire driver, central mode generator, depth sensor and inertial sensor; the processor is used to realize the method in any one of the above-mentioned first aspects, and adjusts the deflection angle of the pectoral fin through the steering gear driver; the pull-wire driver passes the central mode The generator controls the swing amplitude and swing frequency of the caudal fin, and then controls the movement speed of the bionic robotic fish; the depth sensor is used to detect the depth of the bionic robotic fish; the inertial sensor is used to detect the pitch angle of the fish body.

It can be understood that, for the beneficial effects of the above-mentioned second aspect to the fifth aspect, reference may be made to the relevant description of the above-mentioned first aspect and the beneficial effects brought about by each possible implementation manner of the first aspect, and details are not repeated here.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the accompanying drawings that need to be used in the descriptions of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings in the following description are only for the present application For some embodiments, those of ordinary skill in the art can also obtain other drawings based on these drawings without paying creative efforts.

Fig. 1 is a structural diagram of a bionic robotic fish provided by an embodiment of the present application;

Fig. 2 is a cross-sectional view of different viewing angles of the pectoral fin in the bionic robotic fish provided by an embodiment of the present application;

Fig. 3 is a flow chart of a method for controlling the depth of a bionic robotic fish based on the angle of attack method provided by an embodiment of the present application;

Fig. 4 is the flowchart of a kind of fuzzy control method provided by an embodiment of the present application;

Fig. 5 is a flow chart of a fuzzy control method provided by another embodiment of the present application;

Fig. 6 is a kind of diving fuzzy control rule table provided by an embodiment of the present application;

Fig. 7 is a kind of diving fuzzy control table provided by an embodiment of the present application;

Fig. 8 is a kind of upward fuzzy control rule table provided by an embodiment of the present application;

Fig. 9 is a kind of upper-submarine fuzzy control table provided by an embodiment of the present application;

Fig. 10 is a table of fuzzy control rules for fixed-depth cruising provided by an embodiment of the present application;

Fig. 11 is a kind of fixed-depth cruise fuzzy control table provided by an embodiment of the present application;

Fig. 12 is a schematic structural diagram of a depth-fixing control device for a bionic robotic fish based on an angle of attack method provided by an embodiment of the present application.

Detailed ways

In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

Depth control is one of the basic capabilities required for the bionic robotic fish to complete underwater operations, including floating control, diving control, and depth-fixed cruise control. Specifically, the floating control is used to control the bionic robotic fish to move upward from the current depth to the desired depth when the current depth value of the bionic robotic fish is greater than the expected depth value. The dive control is used to control the bionic robotic fish to dive from the current depth to the desired depth when the current depth value of the bionic robotic fish is less than the expected depth value. Depth-fixed cruise control is used to control the movement of the bionic robotic fish at the desired depth.

Existing depth control methods include shape change method, water storage bin method, center of gravity adjustment method, etc. Among them, the shape control method changes the volume of the bionic robotic fish itself, thereby changing the size of the buoyancy to achieve floating and diving movements; the water storage method is to change the self-weight of the bionic robotic fish by absorbing or releasing water, thereby achieving floating and diving movements. These two methods are limited by the size of the bionic robot fish, which makes the depth of the bionic robot fish limited, and the adjustment speed is slow, and the real-time performance of the method is poor. The center of gravity method needs to be equipped with counterweight sliders, screw rods, motors, encoders and other components to adjust the center of gravity to change the pitch angle of the head of the bionic robotic fish to complete the floating and diving movements. The structure of the bionic robotic fish is relatively complicated. These methods need to design complex robotic fish structures or occupy a large space. The real-time performance of the method is poor and lacks mobility. The size of the internal space of the robotic fish leads to a limited number of detection instruments that can be carried, which is not conducive to the expansion of other functional tasks. .

In order to solve the above problems, the embodiment of the present application provides a method and device for controlling the depth of a bionic robotic fish based on the angle of attack method. Determine the actual pectoral fin attack angle of the bionic robot fish at the current moment according to the pitch angle at the current moment and the first deflection angle of the pectoral fin at the previous moment, and the first deflection angle can be calculated in real time by using the actual pectoral fin attack angle and the first expected pectoral fin attack angle. Adjust, and then adjust the pitch angle and motion direction of the bionic robotic fish, so that the bionic robotic fish can generate a larger pitching moment, thereby shortening the path of the bionic robotic fish moving from the first depth to the preset depth range, and improving the real-time accuracy of the fixed depth control method. sex.

The technical solution of the present application will be described in detail below in conjunction with the accompanying drawings. The embodiments described below by referring to the figures are exemplary, and are intended to explain the present application, and should not be construed as limiting the present application.

Fig. 1 is a structural diagram of a bionic robotic fish provided in an embodiment of the present application. Among them, (a) in FIG. 1 is the outline structure diagram of the bionic robotic fish, and (b) in FIG. 1 is a schematic diagram of the internal structure of the bionic robotic fish. As shown in (a) of FIG. 1 , the bionic robotic fish 1 includes: a fish body 11 , a caudal fin 13 arranged on the fish body 11 , and pectoral fins 12 arranged symmetrically on both sides of the fish body.

As shown in (b) among Fig. 1, be provided with processor 14 and the memory 19 that is connected with processor 14 respectively, steering gear driver 17, pull-wire driver 15, central pattern generator 16, inertial sensor 181 in fish body 11 and depth sensor 182 . The depth sensor 182 is used to detect the depth of the bionic robotic fish 1 in real time. The inertial sensor 181 is used to detect the attitude parameters (such as pitch angle, roll angle, etc.), angular velocity, acceleration, and heading angle of the fish body 11 . The steering gear driver 17 is connected with the pectoral fins 12, and the deflection angle of the pectoral fins 12 is regulated by adjusting the rotation angle of the steering gear driver 17. The pull-wire driver 15 is connected to the tail fin 13 through the central pattern generator 16, and the pull-wire driver 15 is used to drive the central pattern generator 16, and controls the swing amplitude and swing frequency of the tail fin 13 through the central pattern generator 16, thereby controlling the bionic robotic fish. 1 movement speed.

The bionic robotic fish also includes a memory 19 . The memory 19 is used to store computer programs 191 and modules, such as the depth-fixing control method for simulated robotic fish based on the angle of attack method provided in this application. The processor 14 executes various functions and data processing of the simulated robotic fish by running the computer programs and modules stored in the memory 19 . Processor 14 may also be a fuzzy controller. The processor 14 can execute the depth-fixing control method of simulated robotic fish based on the angle of attack method provided by the present application according to the data detected by the sensor 18, and send a control signal to the steering gear driver to adjust the deflection angle of the steering gear driver, and then adjust the pectoral fin. 12 deflection angles. The deflection angle of the pectoral fin 12 is the angle between the chord 121 of the pectoral fin 12 and the fish body 11 . Exemplarily, the control signal may be a pulse width modulation signal, and the pulse width of the pulse width modulation signal determines the deflection angle of the steering gear driver. Assuming that the signal period of the pulse width modulation signal is 20MS, the pulse width between 0.5MS and 2.5MS can make the deflection angle of the steering gear driver change linearly from 0 degrees to 180 degrees. The bionic robot fish can be provided with a plurality of steering gear drivers, which are respectively used to control the rotation of the corresponding pectoral fins and flap the wings up and down.

It should be noted that when the bionic robotic fish floats and dives in the water, the pitch angle and pectoral fin attack angle will also change with the change of the bionic robotic fish's posture. As shown in FIG. 1 , the pitch angle θ of the bionic robotic fish 1 is the angle between the fish body 11 and the water flow direction. Assuming that the direction of the water flow is horizontal, when the fish body 11 is horizontally suspended in the water, the pitch angle of the bionic robotic fish 1 is 0; when the bionic robotic fish 1 dives downward, the pitch angle is negative; when the bionic robotic fish 2 floats upward, the pitch angle is a positive value.

Fig. 2 is a cross-sectional view of the pectoral fins of the bionic robotic fish in different deflection states. The cross-sectional shape of the pectoral fin 12 adopts the airfoil profile of an airfoil. Exemplarily, a NACA 0012 or NACA 0020 airfoil curve can be used to generate the cross-sectional shape of the pectoral fin 12 . When the bionic robotic fish 1 swims in water, the forces acting on the pectoral fins 12 are mainly lift and drag. Among them, the resistance is the force generated by the water hindering the movement of the pectoral fin 12 when the bionic robot fish 1 swims, which is opposite to the speed direction of the pectoral fin 12; up the lift. The bionic robotic fish 1 relies on the pectoral fins 12 to interact with water to generate a pitching moment. As shown in (a) in FIG. 2 , the lift center 122 of the general pectoral fin wing is selected as the length of the chord 121 of 0.25 from the leading edge point of the airfoil. When the pectoral fin 12 and the caudal fin 13 jointly drive the bionic robotic fish 1 to move, the periodic swing of the caudal fin 13 makes the bionic robotic fish 1 move at a certain speed, and at the same time, the deflection angle of the pectoral fin 12 makes the bionic robotic fish 1 generate lift and thus generate a pitching moment , and then realize the pitching motion. When the angle of attack of the pectoral fin is positive, the bionic robotic fish 1 generates a pitch moment, when the angle of attack of the pectoral fin is negative, the bionic robotic fish 1 generates a moment of depression, and when the angle of attack of the pectoral fin is zero, the lift force is zero.

As shown in (b) of FIG. 2 , the pectoral fin attack angle α of the bionic robotic fish 1 is the angle between the chord 121 of the pectoral fin 12 and the direction of water flow. Assuming that the direction of water flow is horizontal, when the chord 121 and the direction of water flow are at the same level, the angle of attack of the pectoral fin of the bionic robotic fish 1 is 0, as shown in (a) in Figure 2; the relative direction of water flow points to the lower surface of the pectoral fin 12 , the angle of attack of the pectoral fin of the bionic robotic fish 1 is positive, as shown in (b) in Figure 2; when the relative water flow direction points to the upper surface of the pectoral fin 12, the angle of attack of the pectoral fin of the bionic robotic fish 1 is negative.

In addition, as shown in (b) in Figure 1, the bionic robotic fish 1 also includes sonar, Beidou positioning, industrial control board, wireless communication module, camera, servo motor, water leakage sensor, power battery, etc. connected to the processor 14, etc. part. The structure of the bionic robotic fish provided in this application is exemplary. Other structures of the bionic robotic fish will not be described in detail here.

Based on the bionic robotic fish provided in the above embodiments, the embodiment of the present application also provides a method for controlling the depth of the bionic robotic fish based on the angle of attack method. As shown in Figure 3, in a possible implementation, the method for controlling the depth of the bionic robotic fish based on the angle of attack method includes the following steps:

S100. When the first depth of the bionic robotic fish at the current moment is not within the preset depth range, acquire the pitch angle of the bionic robotic fish at the current moment and the first deflection angle of the pectoral fin of the bionic robotic fish at the previous moment.

It should be noted that when using the bionic robotic fish for underwater operations, it is generally required that the bionic robotic fish can float up or dive to a preset depth, and cruise at a fixed depth within the preset depth range to complete the underwater operations. The preset depth range may be a depth range centered on the preset depth. Exemplarily, the bionic robot fish can be made to swim within the range of its own height. Suppose the preset depth is h, the height of the bionic robotic fish is g, and g≤h, then the preset depth range is [h-g, h+g], and h-g and h+g are the boundaries of the preset depth range.

Exemplarily, the first depth of the bionic robotic fish can be detected in real time by a depth sensor in the bionic robotic fish. Inertial sensors are used to detect the pitch angle of the bionic robotic fish in real time at the current moment. The deflection angle of the steering gear driver is the deflection angle of the pectoral fin.

In one embodiment, when the first depth of the bionic robotic fish is not within the preset depth range, the motion speed of the bionic robotic fish can be the first speed by controlling the swing frequency and swing amplitude of the caudal fin of the bionic robotic fish, and the second One speed is the pitching speed that can make the bionic robotic fish obtain a larger pitching moment.

Specifically, when the first depth of the bionic robotic fish is not within the preset depth range, it is necessary to move the bionic robotic fish from the first depth to the preset depth range by diving or floating. The swing frequency and swing amplitude of the caudal fin will affect the movement speed of the bionic robotic fish, and the periodic swing of the caudal fin can provide thrust for the bionic robotic fish. During the movement of the bionic robotic fish from the first depth to the preset depth range, the pitching moment of the bionic robotic fish is related to the angle of attack of the pectoral fin and the movement speed. The pitching moment needs to make the fish body produce a faster pitching speed. The coordinated propulsion of the caudal fin and the pectoral fin can make the bionic robot fish quickly move from the first depth to the preset depth range. Therefore, the motion speed of the bionic robotic fish can be set to the first speed by controlling the swing frequency and swing amplitude of the tail fin of the bionic robotic fish. Exemplarily, the swing frequency and swing amplitude of the caudal fin of the bionic robotic fish can be adjusted to the maximum value, so that the bionic robotic fish can obtain a larger pitching speed.

S200. Determine the actual pectoral fin attack angle of the bionic robotic fish at the current moment according to the first deflection angle and pitch angle; determine the first expected pectoral fin attack angle according to the relative positional relationship between the first depth and the preset depth range, The angle is used to make the pitching moment of the bionic robotic fish greater than or equal to the first threshold; adjust the first deflection angle to the second deflection angle according to the actual pectoral fin attack angle and the first expected pectoral fin attack angle, so that the bionic robotic fish moves to the preset depth. range of motion.

The pitch attitude of the bionic robotic fish will change with the current and other factors during the movement in the water, and the angle of attack of the bionic robotic fish's pectoral fins at each moment will also change with the change of the pitch angle. According to the first deflection angle and pitch angle, the actual pectoral fin attack angle of the bionic robotic fish at the current moment can be determined, and the specific formula is:

α _c (t)=P ₁ (t-1)+θ(t)

Among them, α _c (t) represents the actual pectoral fin attack angle of the bionic robotic fish at the current moment; P ₁ (t-1) represents the first deflection angle of the bionic robotic fish at the previous moment; The pitch angle at the current moment. In the embodiment of the present application, the pectoral fin attack angle, deflection angle, and pitch angle are all vectors.

In a possible implementation, the method for adjusting the first deflection angle to the second deflection angle according to the actual pectoral fin attack angle and the first expected pectoral fin attack angle includes the following steps:

Step 1: Determine the pectoral fin angle of attack error and pectoral fin angle of attack error change rate between the actual pectoral fin attack angle and the first expected pectoral fin attack angle.

Specifically, the pectoral fin angle of attack error can be expressed as: e _α (t)=α ₁ −α _c (t). Among them, e _α (t) represents the pectoral fin angle of attack error; α ₁ represents the first expected pectoral fin attack angle.

The pectoral fin angle of attack error change rate ec _α can be expressed as:

Step 2: Use the preset first fuzzy control table to perform fuzzy control processing on the pectoral fin angle of attack error and the rate of change of the pectoral fin angle of attack error to obtain the actual control increment.

In the embodiment of the present application, as shown in Fig. 4, the pectoral fin angle of attack error and the rate of change of the pectoral fin angle of attack error can be processed by using the fuzzy control method to obtain the actual control increment. The specific method is as follows: firstly, the pectoral fin angle of attack error e _α and the pectoral fin angle of attack error change rate ec _α are respectively quantified by using the first error quantization factor Ke ₁ and the first error change rate quantization factor Kec ₁ to obtain the quantified pectoral fin attack angle Error E _α and quantitative pectoral fin angle of attack error rate of change EC _α ; then query the preset first fuzzy control table according to the quantified pectoral fin angle of attack error E _α and quantified pectoral fin angle of attack error rate of change EC _α , and obtain the fuzzy control increment U; Use the center of gravity method and the first proportional factor Ku ₁ to defuzzify the fuzzy control increment U to obtain the actual control increment u.

Step 3, adjusting the first deflection angle P ₁ to the second deflection angle P ₂ according to the actual control increment u.

Specifically, the actual control increment u is added to the first deflection angle P ₁ of the bionic robotic fish at the last moment to obtain the second deflection angle P ₂ .

Based on the bionic robotic fish shown in Figure 1, after the processor determines the second deflection angle, it can send a control signal to the steering gear controller, so that the deflection angle of the steering gear controller can be adjusted to the second deflection angle, and then adjust the deflection angle of the pectoral fins , so that the actual pectoral fin attack angle of the bionic robotic fish is close to the first desired pectoral fin attack angle, so that the bionic robotic fish moves from the first depth to the preset depth range in the shortest path. It can be understood that the shortest path should be close to the vertical distance between the first depth and the preset depth range.

In one embodiment, if the first depth of the bionic robotic fish is less than the minimum value of the preset depth range, it means that the bionic robotic fish needs to dive from the first depth to the preset depth range. At this time, the first expected pectoral fin attack angle is used to make the bionic robotic fish generate a pitching moment, and the pitching moment must be greater than or equal to the first threshold, and the first fuzzy control table should be the dive Fuzzy control table.

In another embodiment, if the first depth of the bionic robotic fish is greater than the maximum value of the preset depth range, it means that the bionic robotic fish needs to float up from the first depth to the preset depth range. At this time, the first expected pectoral fin attack angle is used to make the bionic robotic fish generate the upward moment, and the upward moment must be greater than or equal to the first threshold value, and the first fuzzy control table should be the fuzzy control for floating up for controlling the bionic robotic fish to perform upward movement surface.

As an example and not a limitation, through experiments and simulation analysis, it is found that the lift and drag of the simulated robotic fish will change with the change of the angle of attack. The bionic robotic fish quickly moves up and down. Therefore, the first threshold can be set to the maximum pitching moment value generated by the bionic robotic fish, or a value slightly smaller than the maximum pitching moment value generated by the bionic robotic fish. Exemplarily, based on the simulated robotic fish shown in Figure 1 of the present application, when the simulated robotic fish moves in water, the absolute value of the angle of attack of the pectoral fin of the simulated robotic fish is between 1 degree and 15 degrees, and the lift of the simulated robotic fish will vary with The increase of the absolute value increases, and the resistance will basically remain unchanged with the increase of the absolute value; when the absolute value of the pectoral fin attack angle is greater than 15 degrees, the lift of the simulated robotic fish will decrease with the increase of the absolute value. The resistance will increase as the absolute value increases. Therefore, when the absolute value of the pectoral fin attack angle is 15 degrees, the biomimetic robotic fish can generate the maximum pitching moment.

In another possible implementation, when the bionic robotic fish moves from the first depth to the boundary of the preset depth range, the pitch angle of the bionic robotic fish needs to be gradually adjusted to 0 degrees, so that the fish body of the bionic robotic fish is in line with the The flow direction is parallel. Within the preset depth range, after the fish body of the bionic robotic fish is adjusted to a horizontal state, the thrust generated by the tail fin and the deflection angle of the pectoral fin can be used to make the bionic robotic fish swim at a fixed depth within the preset depth range. Therefore, after the above step S200, the bionic robotic fish control method provided by the present application also includes step S300, specifically as follows:

S300, when the bionic robotic fish moves from the first depth to the boundary of the preset depth range, adjust both the first expected pectoral fin attack angle and the third pectoral fin deflection angle to 0; after that, the bionic robotic fish is within the preset depth range During the movement, the fourth deflection angle of the pectoral fin at the current moment is adjusted according to the second depth of the bionic robotic fish at the current moment and the preset depth, and the preset depth is within the preset depth range.

In one embodiment, when it is detected for the first time that the bionic robotic fish moves from the first depth to the boundary value of the preset depth range, the first expected pectoral fin attack angle can be adjusted to the second expected pectoral fin attack angle; according to the second expected The angle of attack of the pectoral fin and the pitch angle of the bionic robotic fish at each moment determine the third deflection angle of the pectoral fin at the corresponding moment. Until the pitch angle of the bionic robotic fish is 0, the third deflection angle is also adjusted to 0.

According to the second expected pectoral fin attack angle α ₂ and the pitch angle θ(t) of the bionic robotic fish at each moment, determine the third deflection angle P ₃ (t) of the pectoral fin at the corresponding moment, which can be expressed as: α ₂ =P ₃ (t)-theta(t).

Wherein, the second expected pectoral fin attack angle is used to make the bionic robotic fish adjust the pitch angle of the bionic robotic fish to 0 degree within a preset depth range.

In one example, assuming that the bionic robotic fish is suspended and swimming horizontally in the water at the first depth, and now the bionic robotic fish needs to dive from the first depth to a preset depth range, the first expected pectoral fin attack angle can be set as - 15 degrees, so that the bionic robotic fish can produce the maximum bending moment. Then, before diving, the deflection angle of the pectoral fin can be adjusted to the first expected pectoral fin angle of attack -15 degrees, so that the bionic robotic fish dives downward. During the diving process, the deflection angle of the pectoral fins is adjusted in real time by using the steps S100 and S200 provided by the present application, so that the bionic robotic fish always dives at the first desired pectoral fin attack angle of -15 degrees. When the bionic robotic fish dives from the first depth to the minimum value of the preset depth range, the first expected pectoral fin attack angle -15 degrees is adjusted to the second expected pectoral fin attack angle +10 degrees.

In another embodiment, when the bionic robotic fish dives from the first depth to the maximum value of the preset depth range, step S300 provided in this application is used to adjust the pitch angle of the bionic robotic fish to 0 degrees, and then the pectoral fins are adjusted to 0 degrees. The deflection angle of is adjusted to 0, and the second expected pectoral fin attack angle is adjusted to the third expected pectoral fin attack angle, and the third expected pectoral fin attack angle is 0. The third expected pectoral fin attack angle is used to make the bionic robotic fish move within a preset depth range, so as to realize constant depth cruise. During the movement of the bionic robotic fish within the preset depth range, the depth of the bionic robotic fish at the current moment is obtained, and the fourth deflection angle of the bionic robotic fish at the current moment is determined according to the depth at the current moment and the preset depth using a fuzzy control algorithm.

It should be noted that when the angle of attack of the pectoral fin of the bionic robotic fish is 0, no pitching moment will be generated, and only relying on the thrust generated by the swing of the tail fin makes the bionic robotic fish cruise within the preset depth range. Therefore, when the pitch angle of the bionic robotic fish is 0 degrees, it means that the fish body is in a horizontal posture. At this time, the deflection angle of the pectoral fins needs to be adjusted to 0 degrees, and the second expected pectoral fin attack angle is adjusted to 0 degrees.

As an example and not a limitation, during the depth-fixed cruise of the bionic robotic fish, the movement speed of the bionic robotic fish can be reduced from the first movement speed to the second movement speed by reducing the swing frequency and swing amplitude of the caudal fin. The second movement speed is the cruising speed calculated to make the cruising distance of the bionic robotic fish longer when the power supply of the bionic robotic fish is limited.

In one embodiment, determining the fourth deflection angle of the bionic robotic fish at the current moment according to the second depth and the preset depth of the bionic robotic fish at the current moment may include the following steps:

Step 1, determining the depth error and depth error change rate of the second depth and the preset depth.

Specifically, the depth error can be expressed as: e _h (t)=hh _c (t). Among them, e _h (t) represents the depth error of the bionic robotic fish at the current moment; h represents the preset depth; h _c (t) represents the second depth of the bionic robotic fish at the current moment.

The rate of change of depth error ec _h can be expressed as:

Step 2, using the preset second fuzzy control table to perform fuzzy control processing on the depth error and the rate of change of the depth error to obtain the fourth deflection angle of the bionic robotic fish at the current moment.

In the embodiment of the present application, as shown in FIG. 5 , a fuzzy control algorithm may be used to process the depth error and the rate of change of the depth error to determine the fourth deflection angle of the pectoral fin at the current moment. The specific implementation method is as follows: first, the second error quantization factor Ke ₂ and the second error change rate quantization factor Kec ₂ are used to fuzzify the depth error e _h and the depth error change rate ec _h respectively (also called quantization processing) , to obtain the quantized depth error E _h and the rate of change of the quantized depth error EC _h ; then query the preset second fuzzy control table according to the quantized depth error E _h and the rate of change of the quantized depth error EC _h to obtain the fuzzy control quantity A; use the center of gravity method And the second proportional factor Ku ₂ performs defuzzification processing on the fuzzy control variable A to obtain the actual control variable a. The actual control amount a is the fourth deflection angle P ₄ of the pectoral fin of the bionic robotic fish at the current moment.

It should be noted that the second fuzzy control table is a fuzzy control table for depth-fixed cruising for the bionic robotic fish within a preset depth range.

Based on the bionic robotic fish shown in Figure 1, after the processor determines the actual control quantity a, it can determine the pulse width of the control signal according to the actual control quantity a, and send the control signal to the steering gear controller, so that the deflection angle of the steering gear controller Adjust to the fourth deflection angle, and then adjust the deflection angle of the pectoral fin, so that the actual angle of attack of the pectoral fin of the bionic robotic fish is close to 0 degrees. If a>0, the bionic robotic fish will ascend; if a<0, the bionic robotic fish will dive. Through the process of floating up and down, the bionic robotic fish can move within the preset depth range, and then the bionic robotic fish can move in the preset depth range. Set depth to maintain constant depth cruise.

The method for formulating the first fuzzy control table and the second fuzzy control table in the embodiment of the present application will be described in detail below.

Taking the first fuzzy control table as a submerged fuzzy control table as an example, the design method of the first fuzzy control table is exemplarily described. Through simulation and experimental experience, the universe of pectoral fin angle of attack error e _α is set to [-3,3] degrees, and the universe of pectoral fin angle of attack error change rate ec _α is set to [-6,6] degrees/s. The domain of discourse controlling the increment u is set to [-3,3] degrees. In the dive movement, with the purpose of the bionic robotic fish quickly approaching the preset depth range, the quantized pectoral fin angle of attack error E _α , the quantified pectoral fin angle of attack error change rate EC _α and the fuzzy control increment U are equally divided into There are 7 quantization levels, that is, the fuzzy subset universe of variables is {-3, -2, -1, 0, 1, 2, 3}, and the corresponding first error quantization factor Ke ₁ =n/e _α ( max)=3/3=1, the first error change rate quantization factor Kec ₁ =n/ec _α (max)=3/6=0.5, the first scaling factor Ku ₁ =u(max)/3=3/3 =1.

In addition, E _α , EC _α and U are equally divided into 7 fuzzy states, which are composed of linguistic variables Negative Big (NB), Negative Medium (NM), Negative Small (NS), Zero (ZE), Positive Small (PS), Median (PM) and Zhengda (PB) are respectively indicated. Determine the membership function of the language value, and give the fuzzy membership function for each of the above languages. Here, the membership function of each language value adopts a trigonometric function. In the process of fuzzy reasoning, the Mamdani maximin method is used for reasoning, and a set of control rules consisting of 49 fuzzy conditional statements is obtained, and the submerged fuzzy control rule table is established according to the control rules. The dive fuzzy control rule table is shown in Figure 6, and the dive fuzzy control table designed based on the dive fuzzy control rule table shown in Figure 6 is shown in Figure 7.

The design method of the floating fuzzy control table is the same as that of the diving fuzzy control table. It's just that the deployment method of the floating fuzzy control rule table is opposite to that of the submerged fuzzy control rule table. The floating fuzzy control rule table is shown in Figure 8, and the floating fuzzy control table designed based on the floating fuzzy control rule table shown in Figure 8 is shown in Figure 9. The value of U in the floating fuzzy control table is opposite to the value of U in the submerged fuzzy control table.

In the depth-fixed cruising stage, through simulation and experimental experience, the discourse domain of the depth error change rate ec _h is set to [-6,6] cm/s, and the discourse domain of the actual control variable a is set to [-6,6] degrees . In order to maintain a high precision in the fixed-depth cruise stage, the fuzzification process divides the quantization depth error E _h , the quantization depth error change rate EC _h and the fuzzy control amount A into 13 quantization levels, that is, the fuzzy subset of variables is taken The domain of discourse is {-6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6}, the second error quantization factor Ke ₂ =n/e _h ( max)=6/18=1/3, the second error change rate quantization factor Kec ₂ =n/ec _h (max)=6/6=1, the second scaling factor Ku ₂ =a(max)/6=6 /6=1.

In addition, E _h , EC _h and A are equally divided into 7 fuzzy states, which are composed of linguistic variables negative large (NB), negative medium (NM), negative small (NS), zero (ZE), positive small (PS), Median (PM) and Zhengda (PB) are respectively indicated. Determine the membership function of the language value, and give the fuzzy membership function for each of the above languages. Here, the membership function of each language value adopts a trigonometric function. In the process of fuzzy reasoning, the Mamdani maxima-minimum method is used for reasoning. The fuzzy control rule table for fixed-depth cruise is shown in Figure 10. The fuzzy control table for fixed-depth cruise is designed based on the fuzzy control rule table for fixed-depth cruise As shown in Figure 11.

The bionic robotic fish depth control method based on the angle of attack method provided by this application can adjust the first deflection angle in real time by using the actual pectoral fin attack angle and the first expected pectoral fin attack angle to adjust the pitch angle and movement direction of the bionic robotic fish. Then adjust the actual pectoral fin attack angle to make it close to the first desired pectoral fin attack angle, so that the bionic robot fish can generate a larger pitching moment and move from the first depth to the preset depth range in the shortest path, thereby shortening the bionic robotic fish. The time it takes for the robot fish to reach the preset depth range. In addition, using the advantages of fuzzy control algorithm in dealing with nonlinear control and uncertainty, the pectoral fin angle of attack error between the actual pectoral fin angle of attack and the first expected pectoral fin angle of attack and the pectoral fin angle of attack The error change rate is processed by fuzzy control to obtain the actual control increment, so as to adjust the first deflection angle in real time. And in the fixed-depth cruising stage, fuzzy control is performed on the depth error and depth difference change rate between the current attack depth and the preset depth to obtain the actual control amount, so that the bionic robot can cruise within the preset depth range to improve the bionic robotic fish. Real-time and accuracy of depth control.

As shown in Fig. 12, based on the same inventive concept, the embodiment of the present application also provides a bionic robot fish depth-fixing control device based on the angle of attack method. The fixed depth control device 400 includes an acquisition unit 401 and a control unit 402 .

Wherein, the acquiring unit 401 is used to acquire the pitch angle of the bionic robotic fish at the current moment and the first depth of the pectoral fin of the bionic robotic fish at the previous moment when the first depth of the bionic robotic fish at the current moment is not within the preset depth range. deflection angle.

The control unit 402 is used to determine the actual pectoral fin attack angle of the bionic robotic fish at the current moment according to the first deflection angle and pitch angle, and determine the first expected pectoral fin attack angle according to the relative positional relationship between the first depth and the preset depth range. The expected pectoral fin attack angle is used to make the pitching moment of the bionic robotic fish greater than or equal to the first threshold, and the first deflection angle is adjusted to the second deflection angle according to the actual pectoral fin attack angle and the first expected pectoral fin attack angle, so that the bionic robotic fish will Preset depth range movement; when the bionic robotic fish moves from the first depth to the boundary of the preset depth range, both the first expected pectoral fin attack angle and the third pectoral fin deflection angle are adjusted to 0, and then the bionic robotic fish During movement within the preset depth range, the fourth deflection angle of the pectoral fins at the current moment is adjusted according to the second depth of the bionic robotic fish at the current moment and the preset depth, and the preset depth is within the preset depth range.

Those skilled in the art can clearly understand that for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used for illustration. In practical applications, the above-mentioned functions can be assigned to different functional units, Completion of modules means that the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment may be integrated into one processing unit, or each unit may exist separately physically, or two or more units may be integrated into one unit, and the above-mentioned integrated units may adopt hardware It can also be implemented in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the protection scope of the present application. For the specific working process of each unit in the above-mentioned apparatus 400, reference may be made to the corresponding process in the foregoing method embodiment, and details are not repeated here.

The embodiment of the present application also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the depth-fixing control method described in the foregoing method embodiments is implemented.

An embodiment of the present application further provides a computer program product, which, when the computer program product is run on a terminal device, enables the terminal device to implement the depth-fixing control method described in the foregoing method embodiments when executed.

Reference to "one embodiment" or "some embodiments" or the like in this application means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in other embodiments," etc. in various places in this specification are not necessarily All refer to the same embodiment, but mean "one or more but not all embodiments" unless specifically stated otherwise. The terms "including", "comprising", "having" and variations thereof mean "including but not limited to", unless specifically stated otherwise.

In the description of the present application, it should be understood that the terms "first" and "second" are used for description purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features.

In addition, in this application, unless otherwise clearly stipulated and limited, the terms "connected" and "connected" should be understood in a broad sense, for example, it can be mechanical connection or electrical connection; it can be direct connection or through An intermediate medium is indirectly connected, which can be the internal communication of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, those of ordinary skill in the art can understand the above terms in this application according to the specific situation. specific meaning.

The above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be applied to the foregoing embodiments The technical solutions described in the examples are modified, or some or all of the technical features are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the application.

Claims

A method for controlling the depth of a bionic robotic fish based on an angle of attack method, characterized in that the method comprises:

When the first depth of the bionic robotic fish at the current moment is not within the preset depth range, obtain the pitch angle of the bionic robotic fish at the current moment, and the first deflection of the pectoral fin of the bionic robotic fish at the previous moment angle;

Determine the actual pectoral fin attack angle of the bionic robotic fish at the current moment according to the first deflection angle and the pitch angle, and determine the first pectoral fin attack angle according to the relative positional relationship between the first depth and the preset depth range. Expected pectoral fin attack angle, the first expected pectoral fin attack angle is used to make the pitching moment of the bionic robotic fish greater than or equal to a first threshold value, and the adjusting the first deflection angle to a second deflection angle, so that the bionic robotic fish moves to the preset depth range;

When the bionic robotic fish moves from the first depth to the boundary of the preset depth range, both the first expected pectoral fin attack angle and the third pectoral fin deflection angle are adjusted to 0, after that, the During the movement of the bionic robotic fish within the preset depth range, adjust the fourth deflection angle of the pectoral fin at the current moment according to the second depth of the bionic robotic fish at the current moment and the preset depth, the preset depth within the preset depth range.
The method according to claim 1, wherein the adjusting the first deflection angle to a second deflection angle according to the actual pectoral fin angle of attack and the first desired pectoral fin attack angle comprises:

determining the pectoral fin angle of attack error and pectoral fin angle of attack error rate of change of the actual pectoral fin angle of attack and the first desired pectoral fin angle of attack;

performing fuzzy control processing on the pectoral fin angle of attack error and the rate of change of the pectoral fin angle of attack error by using the preset first fuzzy control table corresponding to the relative positional relationship to obtain an actual control increment;

The first deflection angle is adjusted to a second deflection angle according to the actual control increment.
The method according to claim 2, wherein the pitching moment comprises a pitching moment and a pitching moment;

If the first depth is less than the minimum value of the preset depth range, the first expected pectoral fin attack angle is used to make the pitching moment of the bionic robotic fish greater than or equal to the first threshold, the The first fuzzy control table is a diving fuzzy control table used to control the bionic robotic fish to dive;

If the first depth is greater than the maximum value of the preset depth range, the first expected pectoral fin attack angle is used to make the pitch moment of the bionic robotic fish greater than or equal to the first threshold, the The first fuzzy control table is a floating fuzzy control table used for controlling the floating movement of the bionic robotic fish.
The method according to claim 1, wherein the adjusting the fourth deflection angle of the pectoral fin at the current moment according to the second depth and the preset depth of the bionic robotic fish at the current moment comprises:

Determining the depth error and depth error change rate of the second depth and the preset depth of the bionic robotic fish at the current moment;

The second preset fuzzy control table is used to perform fuzzy control processing on the depth error and the change rate of the depth error to obtain a fourth deflection angle of the pectoral fin at the current moment.
The method according to any one of claims 1 to 4, wherein the method further comprises:

During the movement of the bionic robotic fish from the first depth to the preset depth range, adjust the swing frequency and swing amplitude of the tail fin of the bionic robotic fish, and set the moving speed of the bionic robotic fish to the first speed ;

During the movement of the bionic robotic fish within the preset depth range, the first speed is adjusted to a second speed, and the second speed is lower than the first speed.
A bionic robotic fish depth-fixing control device based on the angle of attack method, characterized in that the device comprises:

The acquiring unit is used to acquire the pitch angle of the bionic robotic fish at the current moment when the first depth of the bionic robotic fish at the current moment is not within the preset depth range, and the position of the pectoral fin of the bionic robotic fish at the previous The first deflection angle at time;

A control unit, configured to determine the actual pectoral fin attack angle of the bionic robotic fish at the current moment according to the first deflection angle and the pitch angle, and according to the relative position between the first depth and the preset depth range relationship, determine the first expected pectoral fin attack angle, the first expected pectoral fin attack angle is used to make the pitching moment of the bionic robotic fish greater than or equal to the first threshold, according to the actual pectoral fin attack angle and the first expected pectoral fin attack angle The angle of attack adjusts the first deflection angle to a second deflection angle, so that the bionic robotic fish moves to the preset depth range; when the bionic robotic fish moves from the first depth to the preset At the boundary of the depth range, both the first expected angle of attack of the pectoral fin and the third deflection angle of the pectoral fin are adjusted to 0, and then, during the movement of the bionic robotic fish within the preset depth range, according to the The second depth of the bionic robotic fish at the current moment and the preset depth adjust the fourth deflection angle of the pectoral fin at the current moment, and the preset depth is within the preset depth range.
The device according to claim 6, wherein the adjusting the first deflection angle to the second deflection angle according to the actual pectoral fin attack angle and the first expected pectoral fin attack angle comprises:

determining the pectoral fin angle of attack error and pectoral fin angle of attack error rate of change of the actual pectoral fin angle of attack and the first desired pectoral fin angle of attack;

performing fuzzy control processing on the pectoral fin angle of attack error and the rate of change of the pectoral fin angle of attack error by using the preset first fuzzy control table corresponding to the relative positional relationship to obtain an actual control increment;

The first deflection angle is adjusted to a second deflection angle according to the actual control increment.
The device according to claim 7, wherein the pitching moment comprises a pitching moment and a pitching moment;

If the first depth is less than the minimum value of the preset depth range, the first expected pectoral fin attack angle is used to make the pitching moment of the bionic robotic fish greater than or equal to the first threshold, the The first fuzzy control table is a diving fuzzy control table used to control the bionic robotic fish to dive;

If the first depth is greater than the maximum value of the preset depth range, the first expected pectoral fin attack angle is used to make the pitch moment of the bionic robotic fish greater than or equal to the first threshold, the The first fuzzy control table is a floating fuzzy control table used for controlling the floating movement of the bionic robotic fish.
The device according to any one of claims 6 to 8, wherein the fourth deflection angle of the pectoral fin at the current moment is adjusted according to the second depth of the bionic robotic fish at the current moment and the preset depth, include:

Determining the depth error and depth error change rate of the second depth and the preset depth of the bionic robotic fish at the current moment;

The second preset fuzzy control table is used to perform fuzzy control processing on the depth error and the change rate of the depth error to obtain a fourth deflection angle of the pectoral fin at the current moment.
A bionic robotic fish, characterized in that the bionic robotic fish comprises:

The fish body, the caudal fin on the fish body and the pectoral fins symmetrically arranged on both sides of the fish body, a processor and a steering gear driver, a pull-wire driver, Central pattern generator, depth sensor and inertial sensor;

The processor is used to implement the method according to any one of claims 1 to 5, and adjust the deflection angle of the pectoral fin through the steering gear driver; The swing amplitude and swing frequency of the caudal fin, and then control the movement speed of the bionic robotic fish; the depth sensor is used to detect the depth of the bionic robotic fish; the inertial sensor is used to detect the pitch angle of the fish body.