A foldable electrostatic hydraulic driver for a bionic manta ray pectoral fin, a bionic manta ray pectoral fin and a parameter design method thereof

Abstract

The application discloses a folding electrostatic hydraulic driver for a bionic manta ray pectoral fin, the bionic manta ray pectoral fin and a parameter design method thereof. The folding electrostatic hydraulic driver comprises a flexible oil storage sealed bag, a dielectric fluid and electrodes. The flexible oil storage sealed bag is divided into an electrode area and a fluid deformation area. The electrode area is symmetrically attached with electrodes on both sides. The fluid deformation area comprises two deformation chambers. The electrodes are attracted, the dielectric fluid flows from the electrode area to the fluid deformation area, the two deformation chambers are inflated, and the output angle of the driver is increased. In the bionic manta ray pectoral fin, a phase difference is generated by controlling the output angle of the folding electrostatic hydraulic driver, and a propelling force is formed. According to the parameters such as the liquid content in the driver and the length of the deformation chamber, the driving angle design is optimized, the output force of the folding electrostatic hydraulic driver is calculated in combination with the input voltage, the efficiency and scientific nature of the driver design process are realized, the dependence on experiments is reduced, and the design efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of soft bionics technology, and particularly relates to a foldable electro-hydraulic driver for bionic manta ray pectoral fin, a bionic manta ray pectoral fin and a parameter design method thereof. BACKGROUND

[0002] The electro-hydraulic driver is a new type of driver with high ductility, adaptability and low energy consumption. The electro-hydraulic driver usually has a deformable shell (flexible or stretchable), which is covered with a pair of opposite electrodes and filled with liquid dielectric inside. When a voltage is applied to the electrodes, the Maxwell stress acts on the shell and the liquid medium, driving the local redistribution of the liquid medium, resulting in the change of the shape of the shell, so as to realize the conversion of electrical energy into mechanical energy. At present, many domestic and foreign researchers have carried out in-depth research on the electro-hydraulic driver and applied it to the field of soft robots.

[0003] Patent 2024107687136 discloses a water-based swing propeller based on electro-hydraulic driving, which drives the bionic fish tail to swing left and right through a deformation chamber, simulating the propulsion mode of fish; patent 2024104140122 discloses an underwater bionic flexible actuator based on electro-hydraulic driving, which stacks multiple electro-hydraulic drivers to realize the up-down swing of the pectoral fin; patent 2023113467815 discloses an electro-hydraulic driver using rigid electrodes and its manufacturing method, which uses rigid electrodes to increase the output force, but due to the defects of the film material and the structure of the electro-hydraulic driver itself, the angle generated is almost unchanged compared with the angle generated by flexible electrodes. In the paper Spider-Inspired Electrohydraulic Actuators for Fast Soft-Actuated Joints, researchers obtained the rotation angle and output force of the electro-hydraulic driver under different specifications through a large number of experiments; the existing technology has the following problems: 1. The existing electro-hydraulic drivers generally have the technical limitation of small driving angle, which makes it difficult to meet the demand of large angle action in actual application, thereby limiting its application range and functional expansion. 2. The current design method of electro-hydraulic driver mainly relies on a large number of experiments and repeated tests, and lacks a scientific parameterized design system. This design mode not only consumes a lot of time and resources, but also has the problem of low design efficiency, and it is difficult to accurately predict the output performance (such as output force and deformation angle) of the driver, thereby affecting the performance optimization and development process of the driver. SUMMARY

[0004] The application aims to provide a folded electro-hydraulic driver for a bionic manta ray pectoral fin with an improved output angle range and a parameter design method thereof.

[0005] The folded electro-hydraulic driver for the bionic manta ray pectoral fin comprises a flexible oil storage sealed bag, a dielectric fluid and electrodes, the flexible oil storage sealed bag is divided into an electrode area and a fluid deformation area, the flexible oil storage sealed bag on both sides of the electrode area is symmetrically attached with electrodes, and the fluid deformation area comprises two deformation chambers.

[0006] Further, a skirt is left around the sealing area of the flexible oil storage sealed bag.

[0007] Further, the electrodes are flexible electrodes prepared from ion-conductive polyacrylamide hydrogel or rigid electrodes prepared from aluminum foil or copper foil; the area of the electrodes is not greater than the area of the electrode area of the flexible oil storage sealed bag.

[0008] Further, the dielectric fluid is plant transformer oil with good insulation and low viscosity.

[0009] The bionic manta ray pectoral fin comprises a pectoral fin, a side plate, a pectoral fin movable framework, spring sheets, a skin and the folded electro-hydraulic driver, the front end and the rear end of the pectoral fin are respectively arranged on the side plate through the pectoral fin movable framework, the spring sheets are installed on both sides of the pectoral fin movable framework, the folded electro-hydraulic driver is symmetrically installed on both sides of the pectoral fin movable framework, and the outermost deformation chamber of the folded electro-hydraulic driver is fixed in the mounting groove of the side plate.

[0010] The spring sheets can strengthen the rigidity of the soft joints in the pectoral fin movable framework due to the insufficient rigidity of the soft joints, the spring sheets have a certain elastic deformation capacity, and the spring sheets are deformed together with the framework when the folded electro-hydraulic driver moves. When the folded electro-hydraulic driver is powered off, the elastic potential energy stored in the spring sheets is released, which helps the movement of the folded electro-hydraulic driver and makes the liquid in the fluid deformation area of the folded electro-hydraulic driver flow back to the electrode area due to the residual electric field, so that the state of the next movement of the folded electro-hydraulic driver is consistent with that of the previous movement.

[0011] Further, the pectoral fin movable framework comprises a limiting plate, soft joints and a framework, the pectoral fin is installed on the framework, and the widths of the limiting plate, the framework and the soft joints decrease in sequence.

[0012] Further, the projection of the spring sheet is located in the mounting pectoral fin part of the limiting plate, the flexible joint and the skeleton.

[0013] Further, the limiting plate and the skeleton have the same hardness, and the hardness of the flexible joint is less than that of the limiting plate and the skeleton.

[0014] Further, the mounting groove of the side plate is a variable-diameter square hole, and the diameter of the square hole corresponding to the electrode area is less than that of the square hole corresponding to the fluid deformation area.

[0015] The parameter design method of the folding electrostatic hydraulic driver for the bionic manta ray pectoral fin, comprising the following steps:

[0016] (1) Determine the design parameters of the folding electrostatic liquid driver, the length of the fluid deformation area deformation chamber L1=L0, the width of the folding electrostatic liquid driver W=W0, the direct current voltage value U, the length of the electrode area electrode L2=L0 and the liquid content V injected into the flexible oil storage sealing bag practice ;

[0017] (2) Determine the amplitude θ o , wave number w and frequency f of the manta ray pectoral fin, establish a simulation model, and calculate the maximum lift F l of the pectoral fin under the parameters;

[0018] (3) According to the size of the active skeleton of the pectoral fin, determine the length L1=L0 of the deformation chamber of the folding electrostatic hydraulic driver, the width W=W0 and the length L2=L0 of the electrode area electrode;

[0019] (4) Calculate the content of the driver completely filled with dielectric liquid

[0020]

[0021] (5) Determine the actual injection of dielectric liquid content, V practice =V ideal ×n, n=60%

[0022] (6) Calculate the maximum angle θ max of the folding electrostatic hydraulic driver:

[0023]

[0024] In the formula, A is the cross-sectional area of the folding driver, and its y max is the maximum height of the folding driver when deformed when energized;

[0025] (7) Determine the maximum angle θ max of the driver and the optimal wave amplitude θo

[0026] When θ max < 1.05 × θ o , then go to step (9), otherwise go to step (8);

[0027] (8) judge the maximum angle θ max of the driver and the relationship with the optimal fluctuation amplitude 1.05θ o of manta ray:

[0028] When θ max < 1.05 × θ o , then go to step (11), otherwise go to step (13);

[0029] (9) judge the relationship between V practice and V ideal , if V practice ≤ V ideal , go to step (10), otherwise go to step (12);

[0030] (10) increase the content of dielectric liquid in the folding electrostatic hydraulic driver V zpractice , let n = n + 5%, return to step (6);

[0031] (11) calculate the output force of the driver:

[0032]

[0033] the elastic force of the spring sheet

[0034]

[0035] In the formula, ε0 is the vacuum dielectric constant, ε r is the relative dielectric constant of the dielectric liquid, U is the driving voltage, I is the moment of inertia of the spring sheet, E is the elastic modulus of the spring sheet, go to step (16);

[0036] (12) increase the length L1 of the deformation area chamber of the driver, return to step (4);

[0037] (13) reduce the length L1 of the deformation area chamber of the driver, return to step (4);

[0038] (14) increase the driving voltage value U, U ∈ [7000, 12000], let U = U + 1000V, go to step (8), if U > 12000V, go to step (15);

[0039] (15) increase the length L2 of the electrode area of the driver, return to step (11);

[0040] (16) judge the relationship between F and F​l +2F elastic , if F < F l +2F elastic then go to step (14), otherwise end.

[0041] Beneficial effects: compared with the prior art, the present application has the following significant advantages: 1, the present application sets multiple deformation chambers in the fluid deformation area to form a support and increase the output angle range of the folding electro-hydraulic driver; 2, the present application optimizes the driving angle design by changing the key parameters such as the internal liquid content and the deformation chamber length of the driver, and accurately calculates the output force of the folding electro-hydraulic driver in combination with the input voltage condition, so as to realize the efficiency and scientificity of the driver design process, reduce the experimental dependence, and improve the design efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 is a schematic view of the folding electro-hydraulic driver in a natural state;

[0043] Figure 2 is a schematic view of the folding electro-hydraulic driver in a working state;

[0044] Figure 3 is a schematic view of the folding electro-hydraulic driver;

[0045] Figure 4 is a schematic view of the structure of the bionic pectoral fin;

[0046] Figure 5 is a schematic view of the structure of the movable skeleton of the pectoral fin;

[0047] Figure 6 is a schematic view of the movable skeleton of the pectoral fin in a working state of the folding electro-hydraulic driver;

[0048] Figure 7 is a flowchart of designing the folding electro-hydraulic driver according to the related parameters of manta ray. DETAILED DESCRIPTION

[0049] The present application will be further described below in combination with the drawings.

[0050] The folding electro-hydraulic driver 1 for the bionic manta ray pectoral fin according to the present application comprises a flexible oil storage sealed bag 11 containing 5cs silicone oil, and the flexible oil storage sealed bag comprises two areas of an electrode area A and a fluid deformation area B and a rectangular aluminum foil electrode 12.

[0051] The flexible oil storage sealed bag 11 is made of a rectangular Bopp film with good insulation and large tensile force, which is folded twice, and its cross-sectional shape is similar to "Σ". First, the heat sealing machine is used to heat seal along the two edges of the rectangle, and then the appropriate amount of 5cs silicone oil is injected, and finally the heat sealing machine is used to seal. The folded part of the flexible oil storage sealed bag forms the fluid deformation area, and the unfolded part forms the electrode area.

[0052] As shown in Figure 2 The fluid deformation area B is composed of a first deformation chamber B1 and a second deformation chamber B2. The cross sections of the two chambers are rectangular, and the second deformation chamber is located directly above the first deformation chamber. One end of the two chambers is connected to the electrode area of the flexible oil storage sealed bag, realizing the connection between the electrode area and the fluid deformation area.

[0053] The electrode area is pasted with electrodes 12 on the top and bottom, and the electrodes are rectangular in shape. The electrodes are mainly made of aluminum foil as rigid electrodes, and the length and width of the electrodes 12 are slightly smaller than the corresponding dimensions of the electrode area of the flexible oil storage sealed bag.

[0054] The flexible oil storage sealed bag 11 is also designed with a skirt to prevent the generation of electric arc around it when high voltage is applied. The cross section of the electrode area is rectangular, and the length of the electrode area in the flexible oil storage sealed bag 11 is greater than or equal to the length of the fluid deformation area. The dielectric fluid is a 5cs silicone oil with good insulation.

[0055] As shown in Figure 2 When high voltage is applied to the electrode area, the upper and lower electrodes 12 quickly attract each other, and the 5cs silicone oil flows from the electrode area to the fluid deformation area to generate liquid pressure in the two chambers in the fluid deformation area. When the second deformation chamber expands, the first deformation chamber provides support for the expansion of the second chamber. The included angle between the expanded second deformation chamber and the horizontal position will be greater than the included angle when only one chamber expands.

[0056] As shown in Figure 3As shown in the folding electrostatic hydraulic driver manufacturing process, it is mainly made by plastic sealing machine. First, through cutting, a rectangular Bopp film 111 with a length of (6L+4) mm and a width of (W+4) mm is obtained; then, it is folded along the center folding line l1 to obtain a double-layer rectangular film with a length of (3L+4) mm and a width of (W+4) mm; then, it is folded along the outward folding line l2 to obtain a rectangular film with four layers in front with a length of L mm and a width of (W+4) mm, and two layers in back with a length of (L+2) mm and a width of (W+4) mm; finally, a layer of polyimide film 112 with a length of 2W mm, a width of 2L mm and a thickness of 0.075 mm is sandwiched in the middle of the four layers of film in front, the long side a of the rectangular film is heat sealed by the plastic sealing machine, then a proper amount of 5cs silicone oil is injected, and finally it is sealed by the plastic sealing machine.

[0057] As shown in the folding electrostatic hydraulic driver manufacturing process, it is mainly made by plastic sealing machine. First, through cutting, a rectangular Bopp film 111 with a length of (6L+4) mm and a width of (W+4) mm is obtained; then, it is folded along the center folding line l1 to obtain a double-layer rectangular film with a length of (3L+4) mm and a width of (W+4) mm; then, it is folded along the outward folding line l2 to obtain a rectangular film with four layers in front with a length of L mm and a width of (W+4) mm, and two layers in back with a length of (L+2) mm and a width of (W+4) mm; finally, a layer of polyimide film 112 with a length of 2W mm, a width of 2L mm and a thickness of 0.075 mm is sandwiched in the middle of the four layers of film in front, the long side a of the rectangular film is heat sealed by the plastic sealing machine, then a proper amount of 5cs silicone oil is injected, and finally it is sealed by the plastic sealing machine. Figure 4 As shown in the folding electrostatic hydraulic driver manufacturing process, it is mainly made by plastic sealing machine. First, through cutting, a rectangular Bopp film 111 with a length of (6L+4) mm and a width of (W+4) mm is obtained; then, it is folded along the center folding line l1 to obtain a double-layer rectangular film with a length of (3L+4) mm and a width of (W+4) mm; then, it is folded along the outward folding line l2 to obtain a rectangular film with four layers in front with a length of L mm and a width of (W+4) mm, and two layers in back with a length of (L+2) mm and a width of (W+4) mm; finally, a layer of polyimide film 112 with a length of 2W mm, a width of 2L mm and a thickness of 0.075 mm is sandwiched in the middle of the four layers of film in front, the long side a of the rectangular film is heat sealed by the plastic sealing machine, then a proper amount of 5cs silicone oil is injected, and finally it is sealed by the plastic sealing machine.

[0058] As shown in the folding electrostatic hydraulic driver manufacturing process, it is mainly made by plastic sealing machine. First, through cutting, a rectangular Bopp film 111 with a length of (6L+4) mm and a width of (W+4) mm is obtained; then, it is folded along the center folding line l1 to obtain a double-layer rectangular film with a length of (3L+4) mm and a width of (W+4) mm; then, it is folded along the outward folding line l2 to obtain a rectangular film with four layers in front with a length of L mm and a width of (W+4) mm, and two layers in back with a length of (L+2) mm and a width of (W+4) mm; finally, a layer of polyimide film 112 with a length of 2W mm, a width of 2L mm and a thickness of 0.075 mm is sandwiched in the middle of the four layers of film in front, the long side a of the rectangular film is heat sealed by the plastic sealing machine, then a proper amount of 5cs silicone oil is injected, and finally it is sealed by the plastic sealing machine.

[0059] As shown in the folding electrostatic hydraulic driver manufacturing process, it is mainly made by plastic sealing machine. First, through cutting, a rectangular Bopp film 111 with a length of (6L+4) mm and a width of (W+4) mm is obtained; then, it is folded along the center folding line l1 to obtain a double-layer rectangular film with a length of (3L+4) mm and a width of (W+4) mm; then, it is folded along the outward folding line l2 to obtain a rectangular film with four layers in front with a length of L mm and a width of (W+4) mm, and two layers in back with a length of (L+2) mm and a width of (W+4) mm; finally, a layer of polyimide film 112 with a length of 2W mm, a width of 2L mm and a thickness of 0.075 mm is sandwiched in the middle of the four layers of film in front, the long side a of the rectangular film is heat sealed by the plastic sealing machine, then a proper amount of 5cs silicone oil is injected, and finally it is sealed by the plastic sealing machine. Figure 5

[0060] ​The spring sheet 4 has a rectangular cross section. The front end of the spring sheet is provided with a hole corresponding to the joint between the skeleton part 33 and the soft joint part 32, and the end is provided with a hole corresponding to the end of the limiting plate part 31. The spring sheet 4 has the following functions: the skeleton part 33 moves downward due to its own gravity, which strengthens the rigidity of the soft joint part 32 in the chest fin movable skeleton 3; the spring sheet 4 has a certain elastic deformation capacity, which deforms the spring sheet 4 together with the skeleton part 33 when the folding electro-hydraulic driver 1 on the upper surface of the "chimney" moves; when the folding electro-hydraulic driver 1 is powered off, the spring sheet 4 stores a certain elastic potential energy, which helps the movement of the folding electro-hydraulic driver 1 on the lower surface of the "chimney", and the stored elastic potential energy makes the liquid in the fluid deformation area of the folding electro-hydraulic driver 1 flow back to the electrode area, so that the next movement of the folding electro-hydraulic driver 1 is consistent with the previous movement.

[0061] The side plate 5 is a thin plate with a wing-shaped cross section, and the front end and the end of the wing-shaped cross section are provided with open structures. The front end of the open structure slightly extends outward relative to the outer surface of the side plate, and the end extends outward relative to the inner side of the side plate, and the whole presents two "chimney" structures. The limiting plate part 31 in the chest fin movable skeleton 3 is connected to the "chimney" inside the side plate by gluing, so as to divide the "chimney" inside into upper and lower sides. In the front end part, the length of the skeleton part 331 in the "chimney" structure is shorter, and in the end part, the length of the skeleton part 332 in the "chimney" structure is longer. The upper surfaces inside the front and rear "chimneys" are connected by folding electro-hydraulic drivers 111, 113 by gluing, and the lower surfaces are also connected by folding electro-hydraulic drivers 112, 114 by gluing. The "chimney" part inside the side plate is used to accommodate the electrode area of the folding electro-hydraulic driver 1, and the "chimney" part outside the side plate is kept a certain distance from the deformation area of the folding electro-hydraulic drivers 111, 113 to provide stable support and avoid interference with the deformation of the deformation area of the folding electro-hydraulic driver.

[0062] As Figure 6As shown, when the folded electro-hydraulic driver 112 adhered to the lower surface in the opening structure in the first skeleton part 331 is electrified, the folded electro-hydraulic driver 112 will make the first skeleton part 331 bend upwards, when the folded electro-hydraulic driver 113 adhered to the upper surface in the opening structure in the second skeleton part 332 is electrified, the folded electro-hydraulic driver 113 will make the second skeleton part 332 bend downwards, a phase difference is generated between the first skeleton part 331 and the second skeleton part 332, the soft silicone chest fin forms a wave, thereby generating a propelling force.

[0063] The method for designing the folded electro-hydraulic driver according to the manta ray related parameters comprises the following steps:

[0064] (1) The design parameters of the folded electro-hydraulic driver are determined, including that the fluid deformation region comprises two deformation chambers, the lengths of the two deformation chambers are equal, the deformation chamber length of the fluid deformation region is L1=L0, the width of the folded electro-hydraulic driver is W=W0, the length of the electrode of the electrode region is L2=L0, the direct current voltage value is U=7000V, and the liquid content V injected into the flexible oil storage sealed bag practice .

[0065] (2) The amplitude θ of the manta ray chest fin is determined o =47°, the wave number w=0.4, the frequency f=1.0Hz, and a simulation model is established according to the real manta ray chest fin with a certain proportion scaling (2.5%), and then the maximum lift F of the chest fin under the parameters is calculated l =0.17N;

[0066] The three-dimensional model of the manta ray chest fin is imported into Fluent, and a fluid domain with a proper size is set. Appropriate grids are divided, the fluid domain adopts hexahedral grids, and the chest fin model and the fluid domain interface adopt tetrahedral grids.

[0067] The K-omega turbulence model is adopted, the coupling of pressure and velocity in the continuity equation adopts the Simple algorithm, and the convergence residual is set as κ=1×10 -3 .

[0068] The boundary conditions are set, the inlet boundary is set as a velocity inlet, the outlet boundary is set as a pressure outlet, and the periphery is a fixed wall surface.

[0069] The UDF module in the Fluent module is used to define the chest fin motion. The motion of the grid nodes of the manta ray chest fin is mainly defined by using the DEFINE_GRID_MOTION macro, and the coordinates, velocity and pressure of the chest fin grid nodes are accessed by using the Compute_Force_And_Moment macro. The calculation is performed by setting the time step number as 1600, the iteration number as 100 and the time step length as 0.005.

[0070] After the residual κ converges, the calculation is stopped. The lift of the pectoral fin is imported through the post-processing module of Fluent, and the maximum lift F of the pectoral fin in one movement cycle is calculated l = 0.17 N.

[0071] (3) According to the size of the moving skeleton of the pectoral fin, the length L1 = 4 cm and the width W = 4 cm of the folded electrostatic hydraulic driver and the length L2 = 4 cm of the electrode area electrode are preliminarily determined;

[0072] (4) The content of the driver completely filled with dielectric liquid is calculated

[0073]

[0074] (5) The actual injection content of the dielectric liquid V practice = V ideal × n = 14.64 ml, n = 60%.

[0075] (6) The maximum angle θ of the folded electrostatic hydraulic driver is calculated according to the following formula max = 48.54°:

[0076]

[0077] In the formula, A is the cross-sectional area of the folded driver, which y max is the maximum height of the folded driver when it is deformed when energized.

[0078] (7) The relationship between the maximum angle θ of the driver max and the optimal fluctuation amplitude θ of the manta ray o is judged,

[0079] When θ max < θ o , step (9) is entered, otherwise step (8) is entered;

[0080] (8) The relationship between the maximum angle θ of the driver max and the optimal fluctuation amplitude 1.05 θ of the manta ray o is judged:

[0081] When θ max < 1.05 × θ o , step (11) is entered, otherwise step (13) is entered;

[0082] (9) The relationship between V practice and V ideal is judged, if V practice ≤ V ideal , step (10) is entered, otherwise step (12) is entered;

[0083] (10) Increase the dielectric liquid content V in the folded electrostatic hydraulic driver zpractice , let n = n + 5%, return to step (6);

[0084] (11) Calculate the output force of the driver:

[0085]

[0086] The elastic force of the spring sheet

[0087]

[0088] In the formula, ε0 is the vacuum dielectric constant, ε r is the relative dielectric constant of the dielectric liquid, U is the driving voltage, I is the moment of inertia of the spring sheet, E is the elastic modulus of the spring sheet, and step (16) is entered;

[0089] (12) Increase the length L1 of the deformation area chamber of the driver, and return to step (4);

[0090] (13) Reduce the length L1 of the deformation area chamber of the driver, and return to step (4);

[0091] (14) Increase the driving voltage value U, U ∈ [7000, 12000], let U = U + 1000V, enter step (8), if U > 12000V, enter step (15);

[0092] (15) Increase the length L2 of the electrode area of the driver = 12cm, return to step (11);

[0093] (16) Judge F and F l + 2F elastic , if F < F l + 2F elastic , enter step (14), otherwise end.

Claims

1. A parameter design method for a foldable electrostatic hydraulic actuator for a biomimetic manta ray pectoral fin, characterized in that, The foldable electrostatic hydraulic actuator for the biomimetic manta ray pectoral fin includes a flexible oil storage sealing bag, a dielectric fluid, and electrodes. The flexible oil storage sealing bag is divided into an electrode area and a fluid deformation area. Electrodes are symmetrically attached to both sides of the flexible oil storage sealing bag in the electrode area. The fluid deformation area includes two deformation chambers. When a voltage is applied to the electrode area, the upper and lower electrodes are attracted together, and the dielectric fluid flows from the electrode area to the fluid deformation area, causing the two deformation chambers in the fluid deformation area to expand. The parameter design method includes the following steps: (1) Determine the design parameters of the folded electrostatic actuator. The fluid deformation region includes two deformation chambers with equal lengths. The length of the deformation chambers in the fluid deformation region is... The width of the foldable electrostatic actuator DC voltage value U, electrode length in electrode region and the liquid content inside the flexible oil storage sealed bag. ; (2) Determine the amplitude of the manta ray's pectoral fins , wave number and frequency A simulation model was established to calculate the maximum lift of the pectoral fin under these parameters. ; (3) Determine the length of the deformation chamber of the folding electrostatic hydraulic actuator based on the dimensions of the pectoral fin movable skeleton. ,width and the length of the electrode in the electrode region ; (4) Calculate the amount of dielectric fluid that completely fills the inside of the actuator. ; (5) Determine the actual injected dielectric liquid content, , (6) Calculate the maximum angle generated by the folding electrostatic hydraulic actuator. : ； ； In the formula, The cross-sectional area of ​​the folded actuator is... , This refers to the maximum height of the folding actuator when it deforms upon being powered on. (7) Determine the maximum angle of the driver. With the optimal fluctuation amplitude of manta rays Relationship: when If the condition is met, proceed to step (9); otherwise, proceed to step (8). (8) Determine the maximum angle of the driver. With the optimal fluctuation amplitude of manta rays Relationship: when If the condition is met, proceed to step (11); otherwise, proceed to step (13). (9) Judgment and If the relationship, If yes, proceed to step (10); otherwise, proceed to step (12). (10) Increase the dielectric fluid content in the folding electrostatic hydraulic actuator ,make Return to step (6); (11) Calculate the output force of the driver: ； The elastic force of the spring sheet: ； In the formula, The vacuum permittivity, The relative permittivity of the dielectric liquid is... For driving voltage, Let be the moment of inertia of the spring sheet. Given the elastic modulus of the spring sheet, proceed to step (16). (12) Increase the length of the chamber in the deformation region of the actuator. Return to step (4); (13) Reduce the length of the chamber in the deformation region of the actuator Return to step (4); (14) Increase the driving voltage value , ,make Proceed to step (8), if Then proceed to step (15); (15) Increase the length of the driver electrode region Return to step (11); (16) Judgment and ,like If yes, proceed to step (14); otherwise, end.

2. The parameter design method for the foldable electrostatic hydraulic actuator for the biomimetic manta ray pectoral fin according to claim 1, characterized in that, The flexible oil storage sealing bag has a skirt around the sealing area.

3. The parameter design method for the foldable electrostatic hydraulic actuator for the biomimetic manta ray pectoral fin according to claim 1, characterized in that, The electrode is a flexible electrode made of ion-conductive polyacrylamide hydrogel or a rigid electrode made of aluminum foil or copper foil; the area of ​​the electrode is not larger than the area of ​​the electrode region of the flexible oil storage sealing bag.

4. The parameter design method for the foldable electrostatic hydraulic actuator for the biomimetic manta ray pectoral fin according to claim 1, characterized in that, The dielectric fluid is a low-viscosity vegetable transformer oil with good insulation properties.

5. A biomimetic manta ray pectoral fin, characterized in that, The invention includes a pectoral fin, side plates, a movable pectoral fin skeleton, spring plates, skin, and a folding electrostatic hydraulic actuator as described in any one of claims 1-4 for a biomimetic manta ray pectoral fin. The front and rear ends of the pectoral fin are respectively mounted on the side plates through the movable pectoral fin skeleton. Spring plates are installed on both sides of the movable pectoral fin skeleton. The folding electrostatic hydraulic actuator is symmetrically installed on both sides of the movable pectoral fin skeleton. The outermost deformable chamber of the folding electrostatic hydraulic actuator is fixed in the mounting groove of the side plate.

6. The biomimetic manta ray pectoral fin according to claim 5, characterized in that, The pectoral fin skeletal structure includes a limiting plate, a soft joint, and a frame. The pectoral fin is mounted on the frame, and the widths of the limiting plate, the frame, and the soft joint decrease sequentially.

7. The biomimetic manta ray pectoral fin according to claim 6, characterized in that, The projection of the spring plate is located within the limiting plate, soft joint, and the frame where the pectoral fin is mounted.

8. The biomimetic manta ray pectoral fin according to claim 6, characterized in that, The limiting plate and the skeleton have the same stiffness, while the soft joints have less stiffness than the limiting plate and the skeleton.

9. The biomimetic manta ray pectoral fin according to claim 5, characterized in that, The mounting groove of the side plate is a variable diameter square hole, and the diameter of the square hole corresponding to the electrode area is smaller than the diameter of the square hole corresponding to the fluid deformation area.

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