High-speed bionic robotic fish based on caudal fin enhanced propulsion

Abstract

The application relates to the field of machine fish, and particularly discloses a high-speed bionic machine fish based on tail fin enhanced propulsion, which comprises a fish head bionic part, a fish body bionic part and a tail fin piece; the end of the fish body bionic part is movably connected with an open tail bone support; a crank rocker structure is arranged on the fish body bionic part; the crank rocker structure is connected with the open tail bone support; the open tail bone support is partially connected with the tail fin piece; and a tail handle side convex fin piece is arranged on the open tail bone support; the crank rocker structure is used for converting rotary motion into the reciprocating swing action of the whole body of the open tail bone support and the tail fin piece; the tail handle side convex fin piece is used for generating a backward rolling vortex and colliding with the leading edge vortex generated by the tail fin piece in the reciprocating swing process. The open tail bone support is used as the tail handle connecting structure of the machine fish to connect the tail fin piece and the fish body bionic part, so that a faster swimming speed can be obtained under the automatic swimming model of the machine fish.

Description

Technical Field

[0001] This invention relates to the field of biomimetic robotic fish technology, specifically to a high-speed biomimetic robotic fish based on enhanced tail fin propulsion. Background Technology

[0002] With the continuous development of biomimetic technology, the research and application of biomimetic robots, especially biomimetic robotic fish, have gradually gained widespread attention. Current propulsion methods for underwater biomimetic robotic fish mainly include propeller propulsion, medium propulsion, and oscillating propulsion. Robotic fish using propeller propulsion and medium propulsion face the challenge of precisely controlling the high-frequency oscillation and movement of their main body structure.

[0003] In order to mimic the swimming style of fish as much as possible, most biomimetic robotic fish use the swinging of the tail and body to generate propulsion. In order to pursue a streamlined fish body structure, the overall structure is covered with skin. Based on the numerical model of fixed swinging under theoretical flow conditions, this robotic fish structure can indeed achieve a theoretical swimming speed. However, based on the actual free swimming model, it cannot provide a more efficient driving method to achieve a higher driving speed.

[0004] In conclusion, there is a question regarding how to further improve the driving efficiency of existing robotic fish during actual free swimming. Summary of the Invention

[0005] The purpose of this invention is to provide a high-speed biomimetic robotic fish based on tail fin-enhanced propulsion, in order to solve the technical problem in the prior art where there is a need to further improve the driving efficiency of existing robotic fish during actual free swimming.

[0006] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution:

[0007] A high-speed biomimetic robotic fish based on enhanced tail fin propulsion includes a biomimetic head, a biomimetic body, and a tail fin. An open tailbone support is movably connected to the end of the biomimetic body. A crank-rocker structure is provided on the biomimetic body and connected to the open tailbone support. The open tailbone support is partially connected to the tail fin, and a caudal peduncle lateral convex fin is provided on the open tailbone support.

[0008] The crank rocker structure is used to convert the rotational motion into a reciprocating swinging motion of the whole connecting the open tailbone support and the tail fin. The convex fin on the tail peduncle is used to generate a backward rolling vortex and collide with the leading edge vortex generated by the tail fin during the reciprocating swinging process.

[0009] As a preferred embodiment of the present invention, the open tailbone support includes an upper support body and a lower support body, and the upper support body and the lower support body are symmetrically arranged. The ends of the upper support body and the lower support body facing the fish-body bionic part are connected to the ends of the fish-body bionic part through rotating parts.

[0010] The crank-rocker structure is located between the two rotating components.

[0011] As a preferred embodiment of the present invention, the tail shank side convex fins are provided on both the upper support body and the lower support body. The two tail shank side convex fins are arranged in the same vertical plane as the upper support body and the lower support body, and the two tail shank side convex fins are centrally symmetrical.

[0012] As a preferred embodiment of the present invention, the crank rocker structure includes a mating rod and a drive motor disposed inside the bionic part of the fish body. The upper and lower ends of the mating rod are respectively connected to the upper support body and the lower support body, and a sliding groove along the length direction of the mating rod is provided on the mating rod.

[0013] A crank is mounted on the part of the output shaft of the drive motor located outside the bionic fish body. The crank is connected to a rocker arm, and the end of the rocker arm away from the crank is embedded in the groove.

[0014] The crank rotates in a circular motion under the drive of the drive motor, causing the rocker arm to move up and down in the slide groove, and driving the mating rod to oscillate back and forth under the cooperation of the rotating component.

[0015] In a preferred embodiment of the present invention, the rotating component includes a horizontal support section and a connecting frame disposed on the bionic part of the fish body, wherein the connecting frame is rotatably connected to the horizontal support section via a first rotating shaft.

[0016] As a preferred embodiment of the present invention, an encoder is connected to the end of the first rotating shaft, and the encoder is connected to the fish-shaped bionic part through a base bracket.

[0017] As a preferred embodiment of the present invention, the caudal fin has a retainer, the retainer is connected to the open coccyx support via a second pivot, and at least two torsion springs are mounted on the shaft of the second pivot, one end of the torsion spring is connected to the retainer, and the other end is connected to the open coccyx support.

[0018] As a preferred embodiment of the present invention, a counterweight placement groove is provided inside the bionic fish body part.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] This invention uses an open tailbone support as the caudal peduncle connection structure to connect the caudal fin and the biomimetic part of the fish body. Based on the automatic swimming model of the robotic fish and the method of setting the caudal peduncle lateral convex fin on the open tailbone support, faster swimming speed can be obtained.

[0021] The open-type coccyx support, driven by a crank-rocker mechanism, enables smoother swinging motions. Attached Figure Description

[0022] To more clearly illustrate the embodiments of the present invention or the technical solutions in 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 merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the structure of the drive motor installed inside the bionic part of the fish body according to an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the open coccyx structure according to an embodiment of the present invention;

[0026] Figure 4 This is a graph showing the change of thrust coefficients over time for various parts of the robotic fish during a thrust experiment according to an embodiment of the present invention.

[0027] Figure 5 This is a three-dimensional eddy current simulation diagram of the biomimetic robotic fish model at t / T = 0.4 in the thrust experiment of this embodiment of the invention;

[0028] Figure 6 The diagram shows the ωz profile of a horizontal slice and the distribution structure of the thrust CT on the surface of the robotic fish at t / T = 0.4 in the thrust experiment simulation of this embodiment of the invention.

[0029] Figure 7 This is a schematic diagram of the overall structure of the distribution of the surface thrust CT of the robotic fish when t / T = 0.2 in the thrust experiment of this embodiment of the invention.

[0030] The labels in the diagram represent the following:

[0031] 10- Fish head bionic part; 20- Fish body bionic part; 30- Tail fin plate; 40- Open tailbone support; 50- Crank rocker structure; 60- Tail peduncle lateral convex fin plate; 70- Breeding block placement groove;

[0032] 31-Fixer; 32-Second pivot; 33-Torsion spring;

[0033] 41-Upper support body; 42-Lower support body; 43-Rotating component; 44-Horizontal support section; 45-Connecting frame; 46-First rotating shaft; 47-Encoder; 48-Base support;

[0034] 51-Matching rod; 52-Slide groove; 53-Drive motor; 54-Crank; 55-Rock arm. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] like Figures 1 to 7 As shown, the present invention provides a high-speed bionic robotic fish based on tail fin enhanced propulsion, including a fish head bionic part 10, a fish body bionic part 20, and a tail fin 30. An open tailbone support 40 is movably connected to the end of the fish body bionic part 20. A crank rocker structure 50 is provided on the fish body bionic part 20. The crank rocker structure 50 is connected to the open tailbone support 40. The open tailbone support 40 is partially connected to the tail fin 30. A caudal peduncle lateral convex fin 60 is provided on the open tailbone support 40.

[0037] The crank rocker structure 50 is used to convert the rotational motion into a reciprocating swinging motion of the whole connecting the open tailbone support 40 and the tail fin 30. The lateral convex fin 60 of the tail peduncle is used to generate a backward rolling vortex and collide with the leading edge vortex generated by the tail fin 30 during the reciprocating swinging process.

[0038] like Figures 4 to 7 As shown, based on the design of the open tailbone support 40, the thrust coefficient of each part of the robotic fish was tested. When the force is positive, it represents resistance, and when it is negative, it represents thrust. From the thrust coefficient curve, it can be seen that the overall thrust generated by the tail fin of the robotic fish is higher when there is a caudal peduncle convex fin 60.

[0039] The main reason is that the synergistic effect of the caudal peduncle lateral convex fin 60 and the caudal fin can enhance the leading edge vortex of the caudal fin and weaken the trailing edge vortex.

[0040] Among them, the leading edge vortex mainly generates thrust, while the trailing edge vortex mainly generates drag, as can be seen by observing the three-dimensional vortex structure diagram and the ωz profile diagram of the horizontal slice of the biomimetic robotic fish model at t / T = 0.4.

[0041] The vortex generated by the lateral convex fin 60 of the caudal peduncle rolls backward and collides with the leading edge vortex of the caudal fin, inducing a stronger leading edge vortex and enhancing the propulsion performance of the caudal fin, which is consistent with the results in the thrust coefficient variation diagram.

[0042] Since the vortex behind the body of the robotic fish is not so obvious, by comparing the thrust distribution diagram of the robotic fish, it can be concluded that when t / T = 0.4 and there is a 60° lateral convex fin on the caudal peduncle, the low-pressure area of ​​the caudal fin is larger, that is, there is greater thrust, which is consistent with the above conclusion.

[0043] Based on the simulation results, it can be seen that the rotation of the crank and rocker is minimally affected by the frictional resistance of the water. In this embodiment, after simulation, it was found that when the maximum swing angle of the tail fin swing mechanism is 40 degrees and the maximum swing frequency is 9Hz, the experimental results were not good in terms of using skin to cover the crank and rocker to reduce the frictional resistance with the water.

[0044] Meanwhile, the low-pressure area at the trunk and tail is also larger, meaning the trunk generates less drag, which is consistent with the results in the thrust coefficient diagram. When t / T = 0.2, the forces on the tail fins of both are basically the same, but with the tail peduncle 60, the high-pressure area at the trunk and tail is larger, meaning there is greater drag, which is consistent with the results in the thrust coefficient curve diagram.

[0045] Therefore, the synergistic effect between the vortex generated by the lateral convex fin 60 of the caudal peduncle and the leading edge vortex of the caudal fin is the main reason for enhancing the thrust of the caudal fin.

[0046] In this embodiment, multiple caudal peduncle lateral convex fins 60 can be provided, and the size of the caudal peduncle lateral convex fins 60 on the upper support body 41 and / or lower support body 42 gradually decreases in the direction of the caudal fin 30.

[0047] In this embodiment, the open tailbone support 40 specifically refers to a support structure that replaces the tail peduncle structure, compared to the method of covering the tail peduncle structure with skin in robotic fish.

[0048] To more clearly illustrate the working principle of the open coccyx support 40, this embodiment provides an example of the open coccyx support 40, specifically including:

[0049] The upper support body 41 and the lower support body 42 are strip-shaped structures, and the upper support body 41 and the lower support body 42 are symmetrically arranged with respect to the center line of the overall structure of the robotic fish. The ends of the upper support body 41 and the lower support body 42 facing the bionic part 20 of the fish body are connected to the ends of the bionic part 20 of the fish body through the rotating part 43. The extension length and direction of the upper support body 41 and the lower support body 42 in the direction of the fish body can be designed with consideration of the linear structure of the fish body.

[0050] In this embodiment, to facilitate the transition between the biomimetic fish body and the tail fin 30 structure, the width between the upper support body 41 and the lower support body 42 gradually decreases in the direction approaching the tail fin 30, forming an overall trapezoidal shape. Figure 1 and Figure 2 As shown.

[0051] Based on the experiment, it was found that the robotic fish with the skin removed swims faster. In the case of a fixed oscillation under the condition of incoming current, the performance of the robotic fish with the skin removed (wrapped shell) is weaker in terms of drag and thrust coefficients. However, the swimming model of the robotic fish is not a free swimming model and cannot accurately reflect the impact on speed.

[0052] To optimize the driving mechanism of the open coccyx support 40, the crank rocker structure 50 is positioned between the two rotating parts 43.

[0053] Both the upper support body 41 and the lower support body 42 are provided with tail shank side convex fins 60. The two tail shank side convex fins 60 are set in the same vertical plane as the upper support body 41 and the lower support body 42, and the two tail shank side convex fins 60 are centrally symmetrical.

[0054] The crank-rocker structure 50 in this embodiment specifically includes:

[0055] The mating rod 51 and the drive motor 53 are installed inside the fish-body bionic part 20. The upper and lower ends of the mating rod 51 are connected to the upper support body 41 and the lower support body 42 respectively. A sliding groove 52 along the length direction of the mating rod 51 is provided on the mating rod 51.

[0056] The output shaft of the drive motor 53 is mounted with a crank 54 on the part outside the fish-shaped bionic part 20. The crank 54 is connected to a rocker arm 55, and the end of the rocker arm 55 away from the crank 54 is embedded in a groove 52.

[0057] The crank 54 rotates in a circular motion under the drive of the drive motor 53, causing the rocker arm 55 to move up and down in the slide groove 52, and the drive mating rod 51 to oscillate back and forth under the cooperation of the rotating part 43.

[0058] Thus, the structure driving the open tailbone support 30 essentially only includes the rocker arm 55 and the mating rod 51 extending from the bionic part 20 of the robotic fish body, thereby optimizing the crankshaft design, reducing the number of parts, and making the transmission structure more compact and lightweight.

[0059] Of course, to ensure smoother swinging of the open tailbone support 40 and reduce jamming, the end of the mating rod 51 and the connecting frame 45 can be rotatably connected. This optimizes the crankshaft's trajectory, providing smoother swinging motion and avoiding jamming or shaking that may occur in traditional structures, supporting swing frequencies up to 10Hz. This structure allows for a larger tailbone swing angle, thereby enhancing the robotic fish's swimming speed.

[0060] The rotating component 43 in this embodiment includes a horizontal support section 44 and a connecting frame 45 disposed on the fish-body bionic part 20. The connecting frame 45 is rotatably connected to the horizontal support section 44 via a first rotating shaft 46.

[0061] An encoder 47 is connected to the end of the first rotating shaft 46. The encoder 47 is connected to the fish-body bionic part 20 through the base bracket 48. Its purpose is to obtain the rotation status and rotation efficiency of the first rotating shaft 46 through the encoder 47.

[0062] Furthermore, the caudal fin 30 in this embodiment includes a retainer 31, which is connected to the open coccyx support 40 via a second pivot 32. At least two torsion springs 33 are mounted on the shaft of the second pivot 32, with one end of the torsion spring 33 connected to the retainer 31 and the other end connected to the open coccyx support 40.

[0063] The connection between the fixator 31 and the open coccyx support 32 is similar to a hinge connection, and the second pivot 32 is equivalent to the pivot of the hinge. The torsion spring 33 connecting the fixator 31 and the open coccyx support 40 can buffer the tail fin 30 during the reversing swing process, reducing the mechanical wear at the connection between the fixator 31 and the open position frame 40.

[0064] In this embodiment, two torsion springs 33 are provided on the second rotating shaft 32.

[0065] In this embodiment, a counterweight placement groove 70 is provided inside the bionic fish body 20 for installing counterweights. The bionic fish body has a hollow tail cavity inside, and a motor compartment is provided inside the hollow cavity for installing a drive motor. The motor shaft of the drive motor is connected to a crank 54. An annular groove is provided on the front side of the motor compartment for storing a battery.

[0066] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. A high-speed biomimetic robotic fish based on tail fin-enhanced propulsion, comprising a biomimetic head (10), a biomimetic body (20), and a tail fin (30), characterized in that, An open tailbone support (40) is movably connected to the end of the bionic fish body part (20). A crank rocker structure (50) is provided on the bionic fish body part (20). The crank rocker structure (50) is connected to the open tailbone support (40). The open tailbone support (40) is partially connected to the tail fin (30). A caudal peduncle lateral convex fin (60) is provided on the open tailbone support (40). The crank rocker structure (50) is used to convert the rotational motion into a reciprocating swing motion of the whole connecting the open tailbone support (40) and the tail fin (30). The tail peduncle convex fin (60) is used to generate a backward rolling vortex and collide with the leading edge vortex generated by the tail fin (30) during the reciprocating swing. The open tailbone support (40) includes an upper support body (41) and a lower support body (42), and the upper support body (41) and the lower support body (42) are symmetrically arranged. The ends of the upper support body (41) and the lower support body (42) facing the fish body bionic part (20) are connected to the end of the fish body bionic part (20) through a rotating part (43). The crank rocker structure (50) is located between the two rotating parts (43); Both the upper support body (41) and the lower support body (42) are provided with tail peduncle side convex fins (60). The two tail peduncle side convex fins (60) are arranged in the same vertical plane as the upper support body (41) and the lower support body (42), and the two tail peduncle side convex fins (60) are centrally symmetrical. The crank rocker structure (50) includes a mating rod (51) and a drive motor (53) installed inside the fish-body bionic part (20). The upper and lower ends of the mating rod (51) are connected to the upper support body (41) and the lower support body (42) respectively. A sliding groove (52) along the length direction of the mating rod (51) is provided on the mating rod (51). A crank (54) is installed on the part of the output shaft of the drive motor (53) located outside the fish-body bionic part (20). The crank (54) is connected to a rocker arm (55), and the end of the rocker arm (55) away from the crank (54) is embedded in the groove (52). The crank (54) rotates in a circular motion under the drive of the drive motor (53), causing the rocker arm (55) to move up and down in the slide groove (52), and driving the mating rod (51) to oscillate back and forth under the cooperation of the rotating part (43).

2. The high-speed biomimetic robotic fish based on tail fin-enhanced propulsion according to claim 1, characterized in that, The rotating component (43) includes a horizontal support section (44) and a connecting frame (45) disposed on the fish-body bionic part (20). The connecting frame (45) is rotatably connected to the horizontal support section (44) via a first rotating shaft (46).

3. The high-speed biomimetic robotic fish based on tail fin-enhanced propulsion according to claim 2, characterized in that, An encoder (47) is connected to the end of the first rotating shaft (46), and the encoder (47) is connected to the fish-body bionic part (20) via a base bracket (48).

4. The high-speed biomimetic robotic fish based on tail fin-enhanced propulsion according to claim 1, characterized in that, The caudal fin (30) has a retainer (31), which is connected to the open coccyx support (40) via a second pivot (32). At least two torsion springs (33) are mounted on the shaft of the second pivot (32). One end of the torsion spring (33) is connected to the retainer (31), and the other end is connected to the open coccyx support (40).

5. A high-speed biomimetic robotic fish based on tail fin-enhanced propulsion according to claim 1, characterized in that, A counterweight placement groove (70) is provided inside the bionic fish body part (20).

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