Variable stiffness biomimetic caudal fin based on low melting thermoplastic materials and underwater robots

Abstract

The application relates to the technical field of underwater robots, and provides a variable-rigidity bionic tail fin based on low-melting-point thermoplastic material and an underwater robot, the variable-rigidity bionic tail fin based on low-melting-point thermoplastic material comprises a tail fin plate, a tail fin framework, a tail fin shell and a temperature control assembly; the tail fin framework is arranged on at least one side of the tail fin plate, and the tail fin framework is made of low-melting-point thermoplastic material; the temperature control assembly comprises a heating element and a temperature control device, the heating element is arranged on the tail fin framework, and the temperature control device controls the heating temperature of the heating element to adjust the rigidity of the tail fin framework; and the tail fin shell is wrapped around the periphery of the tail fin plate. The uneven rigidity distribution and the multiple rigidity changes of the variable-rigidity bionic tail fin based on low-melting-point thermoplastic material can improve and optimize the swimming performance of a bionic robot fish under various environmental conditions, and the variable-rigidity bionic tail fin based on low-melting-point thermoplastic material has high reliability and practicality.

Description

Technical Field

[0001] This invention relates to the field of underwater robot technology, and in particular to a variable stiffness biomimetic tail fin and underwater robot based on a low melting point thermoplastic material. Background Technology

[0002] Underwater robots have become an important tool for people to conduct marine exploration and underwater operations. Among them, biomimetic robotic fish are different from traditional underwater robots that are driven by propellers. Biomimetic robotic fish have the advantages of high mobility, high efficiency and low noise.

[0003] Fish in nature can use muscle tissue to control changes in the stiffness of their body and tail fin. For most existing biomimetic robotic fish, the tail fin is the primary power source for their swimming. By changing the stiffness of the robotic fish's body and tail fin, its swimming performance can be affected to varying degrees.

[0004] Currently, technologies for improving swimming performance by altering fish body stiffness mainly focus on the mechanical structure design of biomimetic robotic fish. Different mechanical structures can produce fish body stiffness of varying degrees, thereby further enhancing swimming performance. However, most research results concentrate on mechanical design and can only achieve a single stiffness change, which is not easily adjustable online. In other words, for varying swimming conditions, a single stiffness change cannot achieve optimal results in all situations. Summary of the Invention

[0005] This invention provides a variable stiffness biomimetic tail fin and underwater robot based on low melting point thermoplastic material, which can change the problem that the stiffness of the tail fin is not easy to adjust online.

[0006] This invention provides a variable stiffness biomimetic tail fin based on a low melting point thermoplastic material, comprising: a tail fin plate, a tail fin skeleton, a tail fin shell, and a temperature control component;

[0007] The caudal fin skeleton is disposed on at least one side of the caudal fin plate, and the caudal fin skeleton is made of a low melting point thermoplastic material; the temperature control component includes a heating element and a temperature control element, the heating element is disposed on the caudal fin skeleton, and the temperature control element controls the heating temperature of the heating element to adjust the rigidity of the caudal fin skeleton; the caudal fin shell covers the outer periphery of the caudal fin plate.

[0008] According to an embodiment of the present invention, a variable stiffness biomimetic tail fin based on a low melting point thermoplastic material is provided. The temperature control component further includes a temperature measuring element disposed on the tail fin skeleton. The temperature measuring element is electrically connected to the temperature control device. The temperature control device controls the heating element according to the real-time temperature of the temperature measuring element and the target temperature, so that the real-time temperature is equal to the target temperature.

[0009] According to an embodiment of the present invention, a variable stiffness biomimetic tail fin based on a low melting point thermoplastic material is provided. The tail fin skeleton forms an installation space and an opening communicating with the installation space. The temperature measuring element is disposed in the installation space through the opening.

[0010] According to an embodiment of the present invention, a variable stiffness biomimetic tail fin based on a low melting point thermoplastic material is provided. The tail fin skeleton includes a main skeleton, a secondary skeleton, and a branch skeleton. The secondary skeleton is connected to the main skeleton, and the branch skeleton is connected to the secondary skeleton.

[0011] At least one of the main frame, the secondary frame, and the branch frame is provided with the heating element, and the temperature control device can control the heating temperature of each heating element.

[0012] According to an embodiment of the present invention, a variable stiffness biomimetic tail fin based on a low melting point thermoplastic material is provided. The tail fin plate is provided with a through hole, and the tail fin shell includes a first shell and a second shell, wherein the first shell is connected to the second shell through the through hole.

[0013] According to an embodiment of the present invention, a variable stiffness biomimetic tail fin based on a low melting point thermoplastic material is provided. The tail fin plate has a first side and a second side facing away from each other. The first side and the second side are provided with the tail fin skeleton. The tail fin skeleton located on the first side and the tail fin skeleton located on the second side are symmetrically arranged about the tail fin plate.

[0014] According to an embodiment of the present invention, a variable stiffness biomimetic tail fin based on a low melting point thermoplastic material is provided. The variable stiffness biomimetic tail fin based on a low melting point thermoplastic material further includes multiple tail fin pads, which are stacked at the root of the tail fin plates.

[0015] According to an embodiment of the present invention, a variable stiffness biomimetic tail fin based on a low melting point thermoplastic material is provided, wherein multiple tail fin pads are formed with hollow areas, and the tail fin plates are provided with pads corresponding to the hollow areas, and the heating element is connected to the pads through wires.

[0016] In addition, the present invention also provides an underwater robot, including the above-mentioned variable stiffness biomimetic tail fin based on a low melting point thermoplastic material.

[0017] According to an embodiment of the present invention, an underwater robot is provided, wherein the underwater robot is a biomimetic fish, and the biomimetic fish further includes a fish body connected to a variable stiffness biomimetic tail fin. The fish body includes a fish skeleton and a temperature control component. The fish skeleton is made of a low melting point thermoplastic material, and the temperature control component is used to adjust the stiffness of the fish skeleton.

[0018] The present invention provides a variable stiffness bionic tail fin and underwater robot based on low-melting-point thermoplastic material. Temperature control can be used to regulate the temperature of the heating element located on the tail fin skeleton, thereby controlling the stiffness changes of various parts of the tail fin skeleton and thus regulating the overall stiffness of the tail fin. The tail fin skeleton made of low-melting-point thermoplastic polymer material has the advantages of being easy to implement and low-cost. Functionally, it can achieve continuous stiffness changes and online stiffness control, adjusting stiffness while the bionic tail fin moves. Utilizing the non-uniform stiffness distribution and multiple stiffness changes of this variable stiffness bionic tail fin based on low-melting-point thermoplastic material, it is expected to improve and optimize the swimming performance of bionic robotic fish under various environmental conditions, exhibiting strong reliability and practicality. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of the variable stiffness biomimetic tail fin based on low melting point thermoplastic material provided in an embodiment of the present invention;

[0021] Figure 2 This is one of the partial structural schematic diagrams of a variable stiffness biomimetic tail fin based on low melting point thermoplastic material provided in an embodiment of the present invention;

[0022] Figure 3 This is the second partial structural schematic diagram of the biomimetic tail fin based on low-melting-point thermoplastic material provided in the embodiment of the present invention;

[0023] Figure 4 This is the third partial structural schematic diagram of the biomimetic tail fin based on low-melting-point thermoplastic material provided in the embodiments of the present invention.

[0024] Figure label:

[0025] 1. A variable stiffness biomimetic tail fin based on low-melting-point thermoplastic materials;

[0026] 11. Tail fin plate; 111. Through hole; 112. Solder pad;

[0027] 12. Caudal fin skeleton;

[0028] 13. Caudal fin shell;

[0029] 14. Caudal fin pad;

[0030] 15. Temperature measuring element;

[0031] 16. Heating element. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0033] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the variable stiffness biomimetic tail fin 1 based on low melting point thermoplastic material in this embodiment of the invention includes: tail fin plate 11, tail fin skeleton 12, tail fin shell 13, and temperature control component.

[0034] The caudal fin plate 11 can be crescent-shaped. The shape of the caudal fin plate 11 is inspired by the shape of the tuna's caudal fin in nature; its streamlined shape helps reduce drag during tail movement and increases forward thrust. Furthermore, the caudal fin plate 11 can be made of an elastic composite plate, possessing good elasticity.

[0035] Furthermore, the material used for the caudal fin skeleton 12 is a low-melting-point thermoplastic polymer, such as polycaprolactone. This polymer has a low melting point (60°C) and good thermoplasticity, allowing for a large degree of stiffness change within a small range of temperature variations. Additionally, based on the structure of the tuna caudal fin in nature, which exhibits a smooth decrease in thickness from the base to the tip, the thickness design of the caudal fin skeleton 12 also mimics the structure of the tuna caudal fin; in other words, the caudal fin skeleton 12 exhibits a smooth decrease in thickness from the base to the tip.

[0036] It is particularly noteworthy that the base of the caudal fin plate 11 is composed of several layers of elastic composite plates to reinforce the base of the caudal fin, thereby preventing breakage during movement.

[0037] In practical applications, the caudal fin skeleton 12 is located on at least one side of the caudal fin plate 11, that is, the caudal fin skeleton 12 is located on one side of the caudal fin plate 11 or simultaneously on both sides of the caudal fin plate 11. The temperature control assembly includes a heating element 16 and a temperature control device. The heating element 16 is located on the caudal fin skeleton 12, and the heat generated by the heating element 16 can be transferred to the caudal fin skeleton 12. The temperature control device controls the heating temperature of the heating element 16 to adjust the stiffness of the caudal fin skeleton 12. In addition, the caudal fin outer shell 13 covers the outer periphery of the caudal fin plate 11.

[0038] It should be noted that the tail fin shell 13 can be made by injecting elastic molding material into a mold. The silicone tail fin shell 13 covers the tail fin plate 11 and the tail fin skeleton 12, making them sealed and isolated from the outside world. This gives the variable stiffness bionic tail fin good heat insulation function and makes it easy to control the temperature of the thermoplastic material underwater.

[0039] In practical applications, the caudal fin shell 13 also has a streamlined shape, with its thickness smoothly decreasing to zero from the base to the tip. The overall size of the caudal fin shell 13 is slightly larger than that of the caudal fin plate 11, so the caudal fin shell 13 can completely cover the caudal fin plate 11.

[0040] In this embodiment of the invention, the temperature of the heating element 16 located on the caudal fin skeleton 12 can be controlled by a temperature control device, thereby regulating the stiffness changes of each part of the caudal fin skeleton 12 and thus regulating the overall stiffness changes of the caudal fin. The caudal fin skeleton 12 made of low-melting-point thermoplastic polymer material has the advantages of being easy to implement and low-cost. Functionally, it can achieve continuous stiffness changes and online stiffness control, and stiffness adjustment can be achieved while the biomimetic caudal fin is moving. By utilizing the non-uniform stiffness distribution and multiple stiffness changes of the variable stiffness biomimetic caudal fin 1 based on low-melting-point thermoplastic material, it is expected to improve and optimize the swimming performance of the biomimetic robotic fish under various environmental conditions, and has strong reliability and practicality.

[0041] like Figure 4 As shown, in an optional embodiment, the temperature control component further includes a temperature measuring element 15, which is disposed on the tail fin skeleton 12. The temperature measuring element 15 is electrically connected to the temperature control device, and the temperature control device controls the heating element 16 according to the real-time temperature of the temperature measuring element 15 and the target temperature, so that the real-time temperature is equal to the target temperature.

[0042] It should be noted that the temperature sensing element 15 can be a thermistor, and the heating element 16 can be a heating resistor. The heating resistor can be welded to the tail fin plate 11 and directly contact the tail fin skeleton 12 to heat the tail fin skeleton 12 and achieve stiffness changes. The thermistor can be welded to the tail fin plate 11 to monitor the temperature of the tail fin skeleton 12.

[0043] The temperature control device can be connected to an external power supply to achieve temperature control of the tail fin skeleton 12. The stiffness of the material constituting the tail fin skeleton 12 can be changed due to temperature changes, thereby indirectly controlling the stiffness of the tail fin skeleton 12 through temperature control.

[0044] Specifically, when the temperature control is running, the thermistor feedback data is processed to obtain temperature data, and the on / off control of the heating resistor is performed based on the obtained temperature data to ultimately achieve the desired temperature level.

[0045] In practical applications, such as Figure 4As shown, in order to facilitate the installation of the temperature measuring element 15, the tail fin skeleton 12 has an installation space and an opening communicating with the installation space. The temperature measuring element 15 is installed in the installation space through the opening, and the heating element 16 can be installed on the side of the tail fin skeleton 12 away from the tail fin plate 11.

[0046] like Figure 2 , Figure 3 and Figure 4 As shown, in an optional embodiment, the caudal fin skeleton 12 includes a main skeleton, a secondary skeleton, and a branch skeleton, with the secondary skeleton connected to the main skeleton and the branch skeleton connected to the secondary skeleton. At least one of the main skeleton, secondary skeleton, and branch skeleton is provided with a heating element 16, and a temperature control device can control the heating temperature of each heating element 16. For example, the main skeleton, secondary skeleton, and branch skeleton are each provided with a corresponding heating element 16, and the temperature control device can independently control the heating temperature of each heating element 16.

[0047] The caudal fin skeleton 12 can form multiple channels with independently controllable temperature. In other words, the caudal fin skeleton 12 can be designed in a branch-like shape, divided into several segments of channels, forming a corresponding number of independent temperature-controlled channels.

[0048] like Figure 3 As shown, in an optional embodiment, the caudal fin plate 11 is provided with a through hole 111, and the caudal fin shell 13 includes a first shell and a second shell, with the first shell connected to the second shell through the through hole 111.

[0049] Specifically, the caudal fin plate 11 has several through holes 111 distributed on it, which can be used to bond the thermoplastic material on both sides of the caudal fin plate 11 and the caudal fin shell 13, preventing the silicone caudal fin shell 13 and the thermoplastic caudal fin skeleton 12 from separating from the caudal fin plate 11. Among them, the through holes 111 can be circular through holes.

[0050] Furthermore, the caudal fin plate 11 has a first side and a second side facing away from each other, and caudal fin skeletons 12 are provided on the first side and the second side. The caudal fin skeletons 12 located on the first side and the caudal fin skeletons 12 located on the second side are symmetrically arranged about the caudal fin plate 11. In addition, the temperature control controls the stiffness of the two caudal fin skeletons 12 symmetrically arranged about the caudal fin plate 11 to be the same or different.

[0051] Specifically, since the caudal fin skeleton 12 is located on both sides of the caudal fin plate 11, heating resistors need to be arranged on both sides to ensure that the temperature difference between the two sides of the caudal fin plate 11 is not too large. A thermistor is arranged on one side of the caudal fin skeleton 12. For example, the heating resistor is attached to the upper surface of the caudal fin skeleton 12, while the thermistor is arranged inside the caudal fin skeleton 12 on the side closer to the caudal fin plate 11. In this case, each temperature control assembly includes two heating resistors connected in parallel and one thermistor.

[0052] like Figure 3As shown, in an optional embodiment, the variable stiffness biomimetic tail fin 1 based on low melting point thermoplastic material further includes multiple tail fin pads 14, which are stacked at the root of the tail fin plate 11.

[0053] The caudal fin pad 14 is bonded to the root of the caudal fin plate 11 with structural adhesive. In other words, the caudal fin pad 14 is placed at the root of the variable stiffness bionic caudal fin 1 based on a low-melting-point thermoplastic material to strengthen the root of the variable stiffness bionic caudal fin and prevent breakage.

[0054] In this embodiment of the invention, multiple caudal fin pads 14 are stacked on both sides of the caudal fin plate 11 with the same thickness to thicken the root of the variable stiffness bionic caudal fin, making it less prone to breakage under certain motion intensity.

[0055] In an optional embodiment, multiple tail fin pads 14 are formed with hollow areas, and the tail fin 11 is provided with pads 112 corresponding to the hollow areas. The heating element 16 is connected to the pads 112 via wires.

[0056] It should be noted that the tail fin plate 11 can be a printed circuit board; for example, the tail fin plate 11 can be a flexible circuit board. In this case, both the temperature measuring element 15 and the heating element 16 are electrically connected to the pads 112 on the flexible circuit board through the conductive layer inside the flexible circuit board. The pads 112 are used for electrical connection with external functional devices such as temperature control devices.

[0057] In addition, embodiments of the present invention also provide an underwater robot, including the variable stiffness biomimetic tail fin 1 based on low melting point thermoplastic material in the above embodiments.

[0058] Specifically, since the underwater robot includes the variable stiffness bionic tail fin 1 based on low melting point thermoplastic material as described above, and the specific structure of the variable stiffness bionic tail fin 1 based on low melting point thermoplastic material is as described in the above embodiments, the underwater robot shown in this embodiment includes all the technical solutions of the above embodiments, and therefore has at least all the beneficial effects achieved by all the above technical solutions, which will not be elaborated here.

[0059] Specifically, in its initial state, at room temperature (approximately 25°C), the variable stiffness bionic tail fin's framework 12 is in a solid state, exhibiting maximum stiffness. By supplying power to the temperature control component, the temperature levels of various parts of the tail fin framework 12 can be adjusted. By changing the temperature level, the stiffness of a specific part of the tail fin framework 12 is altered, thus changing the overall stiffness of the bionic tail fin and achieving stiffness control.

[0060] In an optional embodiment, the underwater robot is a biomimetic fish, which also includes a fish body connected to a variable stiffness biomimetic tail fin. The fish body includes a fish skeleton and a temperature control component. The fish skeleton is made of a low-melting-point thermoplastic material, and the temperature control component is used to adjust the stiffness of the fish skeleton. The temperature control component may include the aforementioned temperature measuring element 15, heating element 16, and temperature control device. It should be particularly noted that the temperature control device and power supply equipment may be located inside the fish body.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A variable stiffness biomimetic tail fin based on a low-melting-point thermoplastic material, characterized in that, include: Caudal fin plate, caudal fin skeleton, caudal fin shell, and temperature control components; The caudal fin skeleton is disposed on at least one side of the caudal fin plate, and the caudal fin skeleton is made of a low-melting-point thermoplastic material; the temperature control component includes a heating element and a temperature control device, the heating element is disposed on the caudal fin skeleton, and the temperature control device controls the heating temperature of the heating element to adjust the stiffness of the caudal fin skeleton; the caudal fin shell covers the outer periphery of the caudal fin plate; the temperature control component further includes a temperature measuring element, the temperature measuring element is disposed on the caudal fin skeleton, the temperature measuring element is electrically connected to the temperature control device, and the temperature control device controls the heating element according to the real-time temperature and target temperature of the temperature measuring element, so that the real-time temperature is equal to the target temperature; the caudal fin skeleton includes a main skeleton, a secondary skeleton, and a branch skeleton, the secondary skeleton is connected to the main skeleton, and the branch skeleton is connected to the secondary skeleton; at least one of the main skeleton, the secondary skeleton, and the branch skeleton is provided with the heating element, and the temperature control device can control the heating temperature of each heating element.

2. The variable stiffness biomimetic tail fin based on a low-melting-point thermoplastic material according to claim 1, characterized in that, The tail fin skeleton has an installation space and an opening communicating with the installation space, and the temperature measuring element is installed in the installation space through the opening.

3. The variable stiffness biomimetic tail fin based on a low-melting-point thermoplastic material according to claim 1, characterized in that, The caudal fin plate is provided with a through hole, and the caudal fin shell includes a first shell and a second shell, with the first shell connected to the second shell through the through hole.

4. The variable stiffness biomimetic tail fin based on a low-melting-point thermoplastic material according to any one of claims 1 to 3, characterized in that, The caudal fin plate has a first side and a second side facing away from each other. The caudal fin skeleton is provided on the first side and the second side. The caudal fin skeleton located on the first side and the caudal fin skeleton located on the second side are symmetrically arranged about the caudal fin plate.

5. The variable stiffness biomimetic tail fin based on a low-melting-point thermoplastic material according to any one of claims 1 to 3, characterized in that, The variable stiffness biomimetic tail fin based on low melting point thermoplastic material also includes multiple tail fin pads, which are stacked at the base of the tail fin plates.

6. The variable stiffness biomimetic tail fin based on a low-melting-point thermoplastic material according to claim 5, characterized in that, The multiple tail fin pads form a hollow area, and the tail fins are provided with pads corresponding to the hollow areas. The heating element is connected to the pads via wires.

7. An underwater robot, characterized in that, Including the variable stiffness biomimetic tail fin based on low melting point thermoplastic material as described in any one of claims 1 to 6.

8. The underwater robot according to claim 7, characterized in that, The underwater robot is a biomimetic fish, which also includes a fish body connected to the variable stiffness biomimetic tail fin. The fish body includes a fish skeleton and a temperature control component. The fish skeleton is made of a low melting point thermoplastic material, and the temperature control component is used to adjust the stiffness of the fish skeleton.

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