Dielectric elastomer-based decapterus maruadsi-imitated robotic fish and preparation and control method thereof

Abstract

The invention relates to the technical field of bionic robots, and particularly discloses a dielectric elastomer-based decapterus maruadsi-imitated robotic fish and a preparation and control method thereof, the dielectric elastomer-based decapterus maruadsi-imitated robotic fish comprises a robotic fish head, a driving unit, a tail fin, a buoy, a balancing weight and a connecting piece; the driving unit is composed of two bending drivers and an electrode, the end, in a bending state, of each bending driver is fixedly connected with one end of the connecting piece to form a fish fin, and the non-bending parts of the bending drivers are bonded and fixed to form a fish body; the robotic fish head is fixedly connected with the other end of the connecting piece, and the tail fin is pasted and fixed at one end of the fish body; the buoy is fixed to the upper portion of the head of the robotic fish, and the balancing weight is fixed to the lower portion of the head of the robotic fish. The dielectric elastomer-based decapterus-imitating robotic fish provided by the invention adopts the dielectric elastomer to manufacture the bending driver, can better simulate fish swimming, adapts to a complex underwater environment, and effectively improves the working efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of bionic robots, in particular to a bionic robot fish based on a dielectric elastomer and a preparation and control method thereof. Background Art

[0002] Underwater robots are developing rapidly. Early rigid products relied on propellers or jet propulsion, which could accomplish basic underwater tasks, but had poor maneuverability in complex environments, and the noise and disturbances generated by their propulsion methods would interfere with biological research and other work. With the advancement of materials and manufacturing technology, flexible underwater robots have emerged, and bionic robot fish have attracted much attention.

[0003] After a long period of evolution, fish have adapted their body structure and movement patterns to the aquatic environment. Take the trevally as an example. Its special body shape can reduce resistance in the water and achieve efficient swimming. Bionic robot fish draws on this body shape to consume less energy and move faster when operating underwater. Moreover, the bionic robot fish imitates the drive of fish fins and has strong maneuverability. Compared with traditional rigid underwater robots, it can reach the target location more quickly and accurately when performing tasks. Its fish-like appearance also has advantages in fields such as military reconnaissance and biological monitoring, which can avoid disturbing the target and obtain more accurate information.

[0004] As a smart material, dielectric elastomers bring new opportunities for the development of bionic robot fish. They are electroactive polymers that can convert electrical energy into mechanical energy. They have the advantages of large actuation strain, fast response speed, high electromechanical coupling efficiency, low cost, low noise and high energy density. They can be used to make a variety of actuators and have great application potential in the field of robotics, providing an ideal driving method for bionic robot fish.

[0005] However, the development of bionic robot fish currently faces challenges. In terms of driving mode, the power output of existing technologies is not efficient and stable enough, and the performance of some driving materials is poor; material selection must take into account multiple performances; motion control is difficult to accurately simulate the complex movements of fish; in terms of energy supply, existing battery technology cannot meet the needs of long-term and long-distance operations, which limits the application scope and operation time of bionic robot fish. Summary of the invention

[0006] The purpose of the present invention is to propose a trevally-like robotic fish based on dielectric elastomers, which uses dielectric elastomers as drivers to achieve a fully soft structure, can better simulate the swimming of various fish, improve environmental adaptability, and can accurately adjust motion parameters according to actual needs to improve swimming speed and efficiency.

[0007] To achieve the above-mentioned purpose, the present invention proposes a croaker-like robotic fish based on dielectric elastomer, comprising a robotic fish head, a driving unit, a tail fin, a float, a counterweight and a connecting piece; the driving unit is composed of two bending actuators and electrodes, one end of the bending actuator in a bent state is fixedly connected to one end of the connecting piece to form a fish fin, and the unbent part of the bending actuator is glued and fixed to form a fish body; the robotic fish head is fixedly connected to the other end of the connecting piece, and the tail fin is glued and fixed to one end of the fish body; the float is fixed above the robotic fish head, and the counterweight is fixed below the robotic fish head.

[0008] Preferably, the electrode is arranged on the bending actuator.

[0009] Preferably, the fish fins are symmetrically arranged on both sides of the fish body.

[0010] Preferably, the connecting piece is a bending structure, and the bending part can move freely.

[0011] Preferably, the bending actuator is made of a dielectric elastomer, and the head and the tail fin of the robotic fish are made of carbon fiber reinforced plastic (CFRP).

[0012] The present invention also provides a method for preparing a scad-like robotic fish based on a dielectric elastomer, the steps of which are as follows:

[0013] Preparation of bending actuator: Based on the DEMES design, the PET dielectric elastomer sheet was laser cut and hollowed out, and electrodes were added. Fillers were covered on the electrode corners, and the actuator performance was tested.

[0014] Assemble the drive unit: glue and fix one end of the two bending actuators, and connect the other end to the connector at a connection angle of 60°;

[0015] Making the head and tail fin of the robot fish: Using CFRP material to make the head and tail fin of the robot fish according to the size requirements;

[0016] Assemble the robot fish: Assemble the drive unit, the robot fish head and the tail fin, and install the float and counterweight to complete the production of the imitation trevally robot fish.

[0017] The present invention also provides a control method for a scad-like robotic fish based on a dielectric elastomer, and the swimming speed of the robotic fish is controlled by adjusting the frequency and amplitude of a sinusoidal wave driving voltage applied to the scad-like robotic fish.

[0018] Therefore, the present invention proposes a scad-like robotic fish based on a dielectric elastomer and a preparation and control method thereof, and the beneficial effects thereof are as follows:

[0019] (1) The dielectric elastomer-based robot fish proposed in the present invention uses the dielectric elastomer as a driver to achieve a fully soft structure, which can better simulate the swimming of various fish and improve the ability to adapt to the environment.

[0020] (2) The present invention proposes a trevally-mimicking robotic fish based on a dielectric elastomer, whose unique bending actuator structure design and connection angle optimization make the robotic fish more realistic in imitating the swimming pattern of the trevally and improve its motion performance.

[0021] (3) The present invention proposes a jackdaw-like robotic fish based on a dielectric elastomer, which provides a scientific basis for the motion control of the robotic fish by studying the frequency and amplitude of the driving voltage. The motion parameters can be accurately adjusted according to actual needs to improve the swimming speed and efficiency.

[0022] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is an overall structural diagram of a scad-like robotic fish based on a dielectric elastomer according to the present invention;

[0024] Figure 2 It is a schematic diagram of the structure and dimensions of the bending actuator in the present invention;

[0025] Figure 3 A schematic diagram of the connection angle of a bending actuator for a scad-like robotic fish based on a dielectric elastomer according to the present invention;

[0026] Figure 4 Schematic diagram of the swimming speed of the scad robot fish at different frequencies in an embodiment of the present invention;

[0027] Figure 5 Schematic diagram of the swimming speed of the croaker robot fish under different voltages in an embodiment of the present invention.

[0028] Reference numerals

[0029] 1. Robot fish head; 2. Drive unit; 3. Tail fin; 4. Float; 5. Counterweight; 6. Connector; 7. Connection angle. DETAILED DESCRIPTION

[0030] In order to make the technical solutions, advantages and purposes of the present invention clearer, the technical solutions of the embodiments of the present invention are clearly and completely described below. The described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of this application.

[0031] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0032] As a special type of electroactive polymer, dielectric elastomer has a unique ability to convert electrical energy into mechanical energy and can realize driving functions. From the perspective of material properties, it is an elastomeric material with a high dielectric constant. When an external electric field is applied, the dielectric elastomer can quickly change its shape or volume; and when the external electric field is removed, it can quickly return to its initial state. The stress and strain generated in this process realize the effective conversion of electrical energy into mechanical energy.

[0033] Compared with other driving materials, dielectric elastomers have significant advantages. They have high energy density and can store and release more energy in a limited space; they have fast response speed and can respond to changes in electric fields in a short time; they are low in cost and economically feasible in large-scale applications; in addition, they are resistant to strong magnetic interference and can still work stably in complex electromagnetic environments. Based on these characteristics, dielectric elastomers have become an emerging artificial muscle soft driving material that has attracted much attention, showing unique application advantages in many fields such as medical equipment, adaptive optics, mobile robots, mobile manipulators, and MRI-compatible manipulators.

[0034] Embodiment 1

[0035] like Figure 1 As shown, the present invention provides a croaker-like robotic fish based on dielectric elastomer, comprising a robotic fish head 1, a driving unit 2, a tail fin 3, a float 4, a counterweight 5 and a connector 6; the robotic fish head 1 and the driving unit 2 are connected via the connector 6, and the tail fin 3 is glued and fixed to the other end of the driving unit 2; the float 4 is fixed above the robotic fish head 1, and the counterweight 5 is fixed below the robotic fish head 1.

[0036] The driving unit 2 is composed of two bending drivers and electrodes. One end of the bending driver is fixedly connected to the connecting piece 6 in a bent state to form a fish fin, and the connection angle 7 is 60°; the unbent parts of the two bending drivers are glued and fixed to form a fish body, and the fish fins are symmetrically arranged on both sides of the fish body; wherein the connecting piece 6 is a bending structure, and the bending part can move freely.

[0037] Bending actuators made of dielectric elastomers usually use double semicircles or rectangles as the shape of the hollowed-out area of ​​the flexible substrate, and use a laser cutting machine to hollow out the dielectric elastomer PET sheet. The electrode is set on the bending actuator, and the shape is changed to a shape with a shorter frame. Since the electrode width will affect the torque, the electrode width remains unchanged. When the electrode is asymmetric, the center of the area must be close to the bending position. When making a croaker-like robotic fish, the length and stiffness of the drive unit 2 connected to one side of the tail fin 3 must be kept as constant as possible; at the same time, in order to avoid stress concentration, the corners of the electrode part are covered with fillers. Figure 2 The structural dimension parameters of the bending actuator are shown in Table 1.

[0038] Table 1 Structural parameters of bending actuator (unit: mm)

[0039] Material Pre-stretching l w m p t <![CDATA[q1]]> <![CDATA[q2]]> s <![CDATA[n1]]> <![CDATA[n2]]> PET Elongation ratio 4 67 57 38 0.2 0.1 19 30 8 4 6

[0040] Among them, l represents width, w represents height, m ​​represents electrode height, t represents substrate thickness, p represents fixing material thickness, q1 and q2 represent widths of single-sided fixing materials, s represents distance between fixing materials, n1 represents single-sided electrode width, and n2 represents single-sided electrode width.

[0041] like Figure 3 As shown, when the bending actuator is connected to the connecting member 6, the setting is made without being affected by the initial state of the bending actuator, and the connecting member 6 obtains the maximum force at 60°, so the connection angle 7 is set to 60°.

[0042] The robot fish head 1 and tail fin 3 are made of carbon fiber reinforced plastic CFRP. The size of the robot fish head 1 is 80mm long, 57mm high, and 0.2mm thick. The overall length of the imitation scad robot fish is 158mm, the height is 57mm, and the driving area is 950mm. 2 .

[0043] The scad robot fish is driven by fins, and the two fins are symmetrically arranged on both sides of the body. The scad robot fish achieves stable swimming by driving with the help of the fins located on both sides of the body. In view of the propulsion mechanism of the central fin-pair fin mode, the paddling mode is adopted to propel the robot fish forward. The paddling mode is a movement mode based on resistance, which is manifested as a forward and backward movement. When moving, the fins paddling backwards to generate propulsion, and the fins paddling forwards to generate fluid resistance.

[0044] The propulsion speed of the bionic robot fish is affected by a variety of kinematic parameters. When the driving voltage frequency is changed, the speed of the fish fins will change. In order to explore the effect of the driving signal frequency on the swimming speed of the bionic robot fish, the following experiments were conducted:

[0045] 1. The relationship between the driving voltage frequency and the propulsion speed of the croaker robot fish.

[0046] A sinusoidal driving voltage with an amplitude of 4.5 kV is applied to the fish fins. The swimming speed of the bionic robotic fish in the central fin-opposite fin mode is tested. Figure 4 As shown in the figure, the swimming speed of the robot fish at different frequencies. It can be seen from the figure that as the voltage frequency increases, the swimming speed of the bionic fish first increases and then decreases. When the voltage frequency is 3Hz, the swimming speed of the robot fish reaches its maximum value. When the connection angle is 60°, the maximum swimming speed is 8.8mm / s. After the voltage frequency exceeds 3Hz, the swimming speed of the robot fish begins to decrease. When the voltage frequency is 5Hz, the robot fish swims the slowest, and the swimming speed is about 60% lower than that at 2Hz.

[0047] 2. The influence of driving voltage on the swimming speed of the croaker robot fish.

[0048] like Figure 5 As shown in the figure, a sinusoidal driving voltage with a frequency of 3Hz is applied to the fish fins, and the voltage amplitude increases from 4kV to 4.5kV to test the cruising speed of the bionic fish. As can be seen from the figure, with the increase of voltage amplitude, the swimming speed of the bionic fish gradually increases, and the swimming speed reaches the maximum value when the voltage is 4.5kV. In the process of increasing voltage, the amplitude of the fish fin swing also increases, and the maximum swimming speed is 8.81mm / s.

[0049] Embodiment 2

[0050] The present invention also provides a method for preparing a scad-like robotic fish based on a dielectric elastomer, the steps of which are as follows:

[0051] Preparation of bending actuator: Based on the DEMES design, PET sheets were laser cut and hollowed out, electrodes were added, fillers were covered on the electrode corners, and the actuator performance was tested;

[0052] Assemble the drive unit 2: glue and fix one end of the two bending actuators, and connect the other end to the connecting piece 6 at a connection angle of 60°;

[0053] Making the head 1 and tail fin 3 of the robot fish: using CFRP material to make the head 1 and tail fin 3 of the robot fish according to size requirements;

[0054] Assembling the robot fish: Assemble the drive unit 2, the robot fish head 1 and the tail fin 3, and install the float 4 and the counterweight 5 to complete the production of the imitation trevally robot fish.

[0055] Embodiment 3

[0056] The present invention also provides a control method for a scad-like robotic fish based on a dielectric elastomer, and the swimming speed of the robotic fish is controlled by adjusting the frequency and amplitude of a sinusoidal wave driving voltage applied to the scad-like robotic fish.

[0057] Therefore, the present invention provides a trevally-like robot fish based on dielectric elastomer, and a preparation and control method thereof. The dielectric elastomer is used to make a bending driver to achieve a fully soft structure, which can better simulate the swimming of fish and adapt to complex underwater environments. The unique driver structure design ensures stable operation; the 60° connection angle makes it more realistic when imitating the swimming mode of trevally, and the power output is efficient; in addition, the influence of the driving voltage frequency and amplitude on the swimming speed is clarified, and the motion parameters can be accurately adjusted as needed. The maximum swimming speed can reach 8.81 mm / s, effectively improving the operating efficiency.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A scad-like robotic fish based on dielectric elastomer, characterized in that: The robot fish comprises a head, a driving unit, a tail fin, a float, a counterweight and a connecting piece; the driving unit is composed of two bending actuators and electrodes, one end of the bending actuator in a bent state is fixedly connected to one end of the connecting piece to form a fish fin, and the unbent part of the bending actuator is bonded and fixed to form a fish body; the head of the robot fish is fixedly connected to the other end of the connecting piece, and the tail fin is fixedly glued to one end of the fish body; the float is fixed above the head of the robot fish, and the counterweight is fixed below the head of the robot fish.

2. The dielectric elastomer-based robotic fish according to claim 1, characterized in that: The electrode is arranged on the bending actuator.

3. The dielectric elastomer-based robotic fish according to claim 1, characterized in that: The fish fins are symmetrically arranged on both sides of the fish body.

4. The dielectric elastomer-based robotic fish according to claim 1, characterized in that: The connecting piece is a bent structure, and the bent part can move freely.

5. The dielectric elastomer-based robotic fish according to claim 1, characterized in that: The bending actuator is made of dielectric elastomer, and the head and tail fin of the robotic fish are made of carbon fiber reinforced plastic (CFRP).

6. A method for preparing a scad-like robotic fish based on a dielectric elastomer, characterized in that: Here are the steps: Preparation of bending actuator: Laser cutting and hollowing of PET dielectric elastomer sheet and adding electrodes, covering the electrode corners with fillers, and testing the actuator performance; Assemble the drive unit: glue and fix one end of the two bending actuators, and connect the other end to the connector at a connection angle of 60°; Making the head and tail fin of the robot fish: Using CFRP material to make the head and tail fin of the robot fish according to the size requirements; Assemble the robot fish: Assemble the drive unit, the head and tail fin of the robot fish, and install the float and counterweight to complete the production of the imitation trevally robot fish.

7. A control method for a scad-like robotic fish based on a dielectric elastomer, characterized in that: The swimming speed of the robotic fish is controlled by adjusting the frequency and amplitude of the sinusoidal wave driving voltage applied to the robotic fish.

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