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

Abstract

The invention relates to the field of robotic fishes, and particularly discloses a high-speed bionic robotic fish based on tail fin enhanced propulsion, the high-speed bionic robotic fish comprises a fish head bionic part, a fish body bionic part and tail fins, the end part of the fish body bionic part is movably connected with an open tail bone bracket, and a crank rocker structure is arranged on the fish body bionic part; the crank rocker structure is connected with an open tail bone support, the open tail bone support is partially connected with a tail fin, and a tail handle side convex fin is arranged on the open tail bone support; the crank rocker structure is used for converting the rotating motion into the whole reciprocating swing action for connecting the open tail bone support and the tail fin, and the tail handle side convex fin is used for generating eddy current rolling backwards and collides with front edge eddy current generated in the reciprocating swing process of the tail fin. The open type tail bone support serves as a tail handle connecting structure of the robotic fish to connect the tail fin and the fish body bionic part, and a higher swimming speed can be obtained under an automatic swimming model of the robotic fish.

Description

Technical Field

[0001] The invention relates to the technical field of bionic robot fish, and in particular to a high-speed bionic robot fish based on tail fin enhanced propulsion. Background Art

[0002] With the continuous development of bionic technology, the research and application of bionic robots, especially bionic robot fish, have gradually gained wide attention. The existing driving modes of underwater bionic robot fish mainly include propeller propulsion, medium propulsion and swing propulsion. Robot fish using propeller propulsion and medium propulsion have the problem of precise control of high-frequency swing and movement of the main structure of the robot fish itself.

[0003] In order to achieve the bionic robot fish's bionic swimming method of fish as much as possible, most bionic robot fish use the swing of the fish tail and the fish body to achieve propulsion, and in order to pursue a streamlined fish body, the overall structure is covered with skin. This kind of robot fish structure can indeed obtain a theoretical swimming speed based on a numerical model of fixed swing under theoretical incoming flow conditions, but based on an actual free swimming model, it cannot provide a more efficient driving method to obtain a higher driving speed.

[0004] In summary, the existing robot fish has the problem of how to further improve the driving efficiency during the actual free swimming process. Summary of the invention

[0005] The purpose of the present invention is to provide a high-speed bionic robotic fish based on tail fin enhanced propulsion, so as to solve the technical problem in the prior art that there is a way to further improve the driving efficiency of the existing robotic fish during actual free swimming.

[0006] In order to solve the above technical problems, the present invention specifically provides the following technical solutions:

[0007] A high-speed bionic robot fish based on caudal fin enhanced propulsion, comprising a fish head bionic part, a fish body bionic part and a caudal fin, wherein the end of the fish body bionic part is movably connected to an open coccyx support, a crank rocker structure is arranged on the fish body bionic part, the crank rocker structure is connected to the open coccyx support, the open coccyx support is partially connected to the caudal fin, and a caudal peduncle lateral convex fin is arranged on the open coccyx support;

[0008] Among them, the crank rocker structure is used to convert the rotational motion into an overall reciprocating swinging motion that connects the open coccyx support and the tail fin, and the tail handle side fin 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 caudal skeleton 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 both connected to the ends of the fish body bionic part through rotating members;

[0010] The crank-rocker mechanism is located between the two rotating members.

[0011] As a preferred embodiment of the present invention, finlets on the side of the caudal peduncle are provided on both the upper support body and the lower support body. The two finlets on the side of the caudal peduncle and the upper support body and the lower support body are arranged in the same vertical plane, and the two finlets on the side of the caudal peduncle are centrosymmetric.

[0012] As a preferred embodiment of the present invention, the crank-rocker mechanism includes a mating rod and a driving motor arranged inside the fish body bionic part. The upper and lower ends of the mating rod are respectively connected to the upper support body and the lower support body, and a chute is arranged on the mating rod along the length direction of the mating rod;

[0013] A crank is installed on the part of the output shaft of the driving motor located outside the fish body bionic part. The crank is connected to a rocker, and the end of the rocker away from the crank is embedded in the chute;

[0014] Wherein, the crank rotates in a circular motion under the drive of the driving motor, causing the rocker to move up and down in the chute, and driving the mating rod to swing reciprocally under the cooperation of the rotating member.

[0015] As a preferred embodiment of the present invention, the rotating member includes a horizontal support section and a connecting frame arranged on the fish body bionic part. The connecting frame is rotatably connected to the horizontal support section through 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 body bionic part through a base support.

[0017] As a preferred embodiment of the present invention, the caudal fin has a fixator. The fixator is connected to the open caudal skeleton through a second rotating shaft. At least two torsion springs are sleeved on the shaft body of the second rotating shaft. One end of the torsion spring is connected to the fixator, and the other end is connected to the open caudal skeleton.

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

[0019] The present invention has the following beneficial effects compared with the prior art:

[0020] The present invention uses an open caudal bone bracket as the connecting structure of the tail handle of the robotic fish to connect the caudal fin and the fish body bionic part. Based on the automatic swimming model of the robotic fish and the method of setting the tail handle side convex fins on the open caudal bone bracket, a faster swimming speed can be obtained.

[0021] Based on the open caudal bone bracket, a smoother swinging motion can be obtained by driving through a crank-rocker mechanism. Brief Description of the Drawings

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained based on the provided drawings.

[0023] Figure 1 Schematic diagram of the overall structure of the embodiment of the present invention;

[0024] Figure 2 Schematic diagram of the structure of the drive motor arranged in the fish body bionic part in the embodiment of the present invention;

[0025] Figure 3 Schematic diagram of the open caudal bone structure in the embodiment of the present invention;

[0026] Figure 4 Graph of the thrust coefficient of each part of the robotic fish changing with time in the thrust experiment of the embodiment of the present invention;

[0027] Figure 5 Three-dimensional eddy current simulation diagram of the bionic robotic fish model when t / T = 0.4 in the thrust experiment of the embodiment of the present invention;

[0028] Figure 6 Schematic diagram of the ωz contour of the horizontal slice and the distribution structure of the surface thrust CT of the robotic fish when t / T = 0.4 in the thrust experiment simulation of the embodiment of the present invention;

[0029] Figure 7 Overall structure diagram of the distribution of the surface thrust CT of the robotic fish when t / T = 0.2 in the thrust experiment of the embodiment of the present invention.

[0030] The reference numerals in the drawings are respectively represented as follows:

[0031] 10 - Bionic head part; 20 - Bionic fish body part; 30 - Caudal fin; 40 - Open caudal bone bracket; 50 - Crank-rocker structure; 60 - Tail handle side convex fin; 70 - Breeding block placement groove;

[0032] 31 - Fixator; 32 - Second rotating shaft; 33 - Torsion spring;

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

[0034] 51 - Matching rod; 52 - Chute; 53 - Driving motor; 54 - Crank; 55 - Rocker. Specific embodiments

[0035] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] As Figures 1 to 7 shown, the present invention provides a high - speed bionic robotic fish based on caudal fin enhanced propulsion, including a fish head bionic part 10, a fish body bionic part 20 and a caudal fin piece 30. The end of the fish body bionic part 20 is movably connected with an open caudal bone support 40. A crank - rocker mechanism 50 is arranged on the fish body bionic part 20. The crank - rocker mechanism 50 is connected to the open caudal bone support 40. The open caudal bone support 40 is partially connected to the caudal fin piece 30. A caudal peduncle side convex fin 60 is arranged on the open caudal bone support 40.

[0037] Among them, the crank - rocker mechanism 50 is used to convert the rotational motion into a reciprocating swinging motion of the whole connecting the open caudal bone support 40 and the caudal fin piece 30. The caudal peduncle side convex fin 60 is used to generate a backward - rolling eddy current, and collides with the leading - edge eddy current generated during the reciprocating swing of the caudal fin piece 30.

[0038] As Figures 4 to 7 shown, based on the design of the open caudal bone support 40, experiments on the thrust coefficient of each part of the robotic fish are carried out. Among them, when the force is positive, it represents resistance, and when it is negative, it represents thrust. It can be seen from the thrust coefficient curve graph that the overall thrust generated by the caudal fin of the robotic fish is higher under the condition with the caudal peduncle side convex fin 60.

[0039] The main reason is that the synergistic effect of the caudal peduncle side 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, and the trailing - edge vortex mainly generates resistance, which can be seen by observing the three - dimensional eddy current structure diagram and the ωz contour diagram of the horizontal section of the bionic robotic fish model at t / T = 0.4.

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

[0042] Since the post-body vortex of the trunk of the robotic fish is relatively less obvious, by comparing the thrust distribution diagrams of the robotic fish, it can be obtained that when t / T = 0.4, the low-pressure area of the caudal fin is larger with the caudal peduncle convex fin 60, that is, there is a 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 little affected by the frictional resistance of the water body. In this embodiment, after simulation, it is found that when the maximum swing angle of the caudal fin blade swing mechanism is 40 degrees and the maximum swing frequency is 9 Hz, from the perspective of using the skin to wrap the crank and rocker parts to reduce the frictional resistance with the water body, the experimental results are not good.

[0044] At the same time, the low-pressure area at the tail of the trunk is also larger, that is, the trunk generates less resistance, which is consistent with the results in the thrust coefficient diagram; when t / T = 0.2, the forces on the caudal fins of both are basically the same, while in the case of having the caudal peduncle convex fin 60, the high-pressure area at the tail of the trunk is larger, that is, there is greater resistance, which is consistent with the results in the thrust coefficient curve diagram.

[0045] Therefore, the synergistic effect between the vortex generated by the caudal peduncle convex fin 60 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 convex fins 60 can be provided, and the sizes of the caudal peduncle convex fins 60 on the upper support body 41 and / or the lower support body 42 facing the direction of the caudal fin blade 30 gradually decrease.

[0047] The open caudal bone bracket 40 in this embodiment specifically refers to using a bracket structure to replace the caudal peduncle structure compared with the way of wrapping the caudal peduncle structure of the robotic fish with skin.

[0048] To more clearly illustrate the working principle of the open caudal bone bracket 40, this embodiment provides an embodiment of the open caudal bone bracket 40, which specifically includes:

[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 midline of the overall structure of the robotic fish. The ends of the upper support body 41 and the lower support body 42 facing the fish body bionic part 20 are both connected to the ends of the fish body bionic part 20 through rotating parts 43. The extension length and direction of the upper support body 41 and the lower support body 42 in the fish body direction can be designed in consideration of the linear structure of the fish body.

[0050] In this embodiment, in order to achieve a smooth transition between the fish body bionic part and the tail fin piece 30, the width between the upper support body 41 and the lower support body 42 gradually decreases in the direction approaching the tail fin piece 30, presenting a trapezoidal shape as Figure 1 and Figure 2 shown.

[0051] Based on experiments, it is found that the swimming speed of the robotic fish without the skin is faster. In the numerical model of fixed oscillation under oncoming flow, simply considering the resistance and thrust coefficient, the performance of the robotic fish without the skin (the wrapped outer shell) is weaker. 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 method of the open tailbone bracket 40, the crank-rocker structure 50 is positioned between the two rotating parts 43.

[0053] On both the upper support body 41 and the lower support body 42, there are tail handle side convex fin pieces 60. The two tail handle side convex fin pieces 60, the upper support body 41, and the lower support body 42 are arranged in the same vertical plane, and the two tail handle side convex fin pieces 60 are centrosymmetric.

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

[0055] A mating rod 51 and a driving motor 53 arranged inside the fish body bionic part 20. The upper and lower ends of the mating rod 51 are respectively connected to the upper support body 41 and the lower support body 42. A chute 52 is arranged on the mating rod 51 along the length direction of the mating rod 51.

[0056] A crank 54 is installed on the part of the output shaft of the driving motor 53 located outside the fish body bionic part 20. The crank 54 is connected to a rocker 55, and the end of the rocker 55 far from the crank 54 is embedded in the chute 52.

[0057] Among them, the crank 54 rotates in a circular motion under the drive of the driving motor 53, causing the rocker 55 to move up and down in the chute 52, and driving the mating rod 51 to swing reciprocally under the cooperation of the rotating part 43.

[0058] In this way, the structure for driving the open tailbone bracket 30 essentially only includes the rocker 55 and the mating rod 51 extending out of the fish body bionic part 20 of the robotic fish, thereby optimizing the design of the crankshaft, reducing the number of components, and making the transmission structure more compact and lightweight.

[0059] Of course, in order to make the swing of the open caudal vertebra bracket 40 smoother and reduce jamming, the end of the cooperating rod 51 and the connecting frame 45 can be set to be rotatably connected. Further optimizing the operating trajectory of the crankshaft can provide a smoother swinging motion, avoid jamming or jitter phenomena that may occur in traditional structures, and support a swinging frequency of up to 10 HZ. Such a structure can achieve a larger caudal vertebra swing angle, thereby enhancing the swimming speed of the robotic fish.

[0060] The rotating member 43 in this embodiment includes a horizontal bracket section 44 and a connecting frame 45 provided on the fish body bionic part 20. The connecting frame 45 is rotatably connected to the horizontal bracket section 44 through 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 a base bracket 48, and its purpose is to obtain the rotation condition and rotation efficiency of the first rotating shaft 46 through the encoder 47.

[0062] Furthermore, the caudal fin piece 30 in this embodiment is equipped with a fixator 31. The fixator 31 is connected to the open caudal vertebra bracket 40 through a second rotating shaft 32. At least two torsion springs 33 are sleeved on the shaft body of the second rotating shaft 32. One end of the torsion spring 33 is connected to the fixator 31, and the other end is connected to the open caudal vertebra bracket 40.

[0063] The connection method between the fixator 31 and the open caudal vertebra bracket 32 is similar to a hinge connection here, and the second rotating shaft 32 is equivalent to the core shaft of the hinge. Among them, the torsion spring 33 connecting the fixator 31 and the open caudal vertebra bracket 40 can buffer during the process of the caudal fin piece 30 swinging in the reverse direction, reducing the mechanical loss at the connection between the fixator 31 and the open position skeleton 40.

[0064] Two torsion springs 33 are provided on the second rotating shaft 32 in this embodiment.

[0065] In this embodiment, a counterweight placement groove 70 is provided inside the fish body bionic part 20 for installing counterweights. The interior of the bionic fish body part is a hollow cavity. A motor chamber is provided in the hollow cavity for installing a driving motor. The motor shaft of the driving motor is connected to a crank 54. An annular groove is provided on the front side of the motor chamber for storing battery blocks.

[0066] The above embodiments are only exemplary embodiments of the present application and are not used to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements within the essence and protection scope of the present application, and such modifications or equivalent replacements should also be regarded as falling within the protection scope of the present application.

Claims

1. A high-speed bionic robotic fish based on tail fin enhanced propulsion, comprising a fish head bionic part (10), a fish body bionic part (20) and a tail fin (30), characterized in that: The end of the fish body bionic part (20) is movably connected to an open coccyx support (40), a crank rocker structure (50) is provided on the fish body bionic part (20), the crank rocker structure (50) is connected to the open coccyx support (40), the open coccyx support (40) is partially connected to the caudal fin (30), and a caudal peduncle lateral convex fin (60) is provided on the open coccyx support (40); The crank rocker structure (50) is used to convert the rotational motion into an integral reciprocating swinging motion that connects the open coccyx support (40) and the tail fin (30), and the tail handle side convex fin (60) is used to generate a vortex that rolls backwards and collides with the leading edge vortex generated by the tail fin (30) during the reciprocating swinging process.

2. A high-speed bionic robotic fish based on tail fin enhanced propulsion according to claim 1, characterized in that: The open coccyx support (40) comprises 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, and 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 ends of the fish body bionic part (20) via a rotating member (43); The crank rocker structure (50) is located between the two rotating members (43).

3. The high-speed bionic robotic fish based on tail fin enhanced propulsion according to claim 2, characterized in that: The caudal shank side convex fins (60) are provided on both the upper support body (41) and the lower support body (42); the two caudal shank 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 caudal shank side convex fins (60) are centrally symmetrical.

4. The high-speed bionic robotic fish based on tail fin enhanced propulsion according to claim 3, characterized in that: The crank rocker structure (50) comprises a matching rod (51) and a driving motor (53) arranged inside the fish body bionic part (20); the upper and lower ends of the matching rod (51) are respectively connected to an upper bracket body (41) and a lower bracket body (42); and a sliding groove (52) is arranged on the matching rod (51) along the length direction of the matching rod (51); A crank (54) is installed on the part of the output shaft of the driving motor (53) located outside the fish body bionic part (20), the crank (54) is connected to a rocker (55), and the end of the rocker (55) away from the crank (54) is embedded in the slide groove (52); The crank (54) is driven by a driving motor (53) to rotate in a circle, so that the rocker (55) moves up and down in the slide groove (52), and drives the matching rod (51) to swing back and forth under the cooperation of the rotating member (43).

5. The high-speed bionic robotic fish based on tail fin enhanced propulsion according to claim 2, characterized in that: The rotating member (43) comprises a horizontal support segment (44) and a connecting frame (45) arranged on the fish body bionic part (20); the connecting frame (45) is rotatably connected to the horizontal support segment (44) via a first rotating shaft (46).

6. The high-speed bionic robotic fish based on tail fin enhanced propulsion according to claim 5, 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).

7. The high-speed bionic robotic fish based on tail fin enhanced propulsion according to claim 1, characterized in that: The tail fin (30) is provided with a fixer (31), and the fixer (31) is connected to the open coccyx support (40) via a second rotating shaft (32). At least two torsion springs (33) are mounted on the shaft body of the second rotating shaft (32), and one end of the torsion spring (33) is connected to the fixer (31), and the other end is connected to the open coccyx support (40).

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

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