Crank link drive bionic fish tail mechanism

Abstract

This invention provides a crank-connecting rod driven bionic fish tail mechanism, including a support frame (1) on which tension / compression sensors (2) and bearings (5) are mounted. A tripod (4) is connected to the tension / compression sensors (2) and bearings (5) respectively, and the lower end of the tripod (4) is connected to a first horizontal plate (10) through a vertical support plate (6). It also includes a waterproof motor (7) connected to the first horizontal plate (10). The shaft of the waterproof motor (7) drives the first crank disc (27), the second crank disc (28), and the third crank disc (29) supported by concentric bearings within a rigid frame to rotate via a crank-connecting rod drive mechanism. A first pull rope (32), a second pull rope (33), and a third pull rope (34) are respectively wound around the first crank disc (27), the second crank disc (28), and the third crank disc (29) and are respectively fastened to the fish tail joint structure. This mechanism can adjust the phase difference of the fish tail to achieve a fish tail wave effect where the front joint drives the rear joint.

Description

Technical Field

[0001] This invention relates to the field of underwater biomimetic robots, and particularly to a crank-connecting rod driven biomimetic fish tail mechanism. Background Technology

[0002] The ocean is a vital component of the global life support system, covering up to 71% of the Earth's surface. It contains abundant energy, mineral, and biological resources, making it a valuable asset for the sustainable development of human society. Human development and utilization of the ocean are accelerating with advancements in science and technology. As socio-economic development progresses and human activities in marine exploration become more frequent and in-depth, various high-performance autonomous underwater robots with functions such as marine resource exploration, underwater environmental monitoring, biological observation, energy extraction, and military reconnaissance have been developed. These robots possess broad application prospects and enormous potential value.

[0003] While theoretical research on the locomotion mechanisms of fish continues to advance, research institutions both domestically and internationally are constantly developing biomimetic robotic fish for different work objectives. When a fish undulates, its body drives its tail to undulate, similar to how the thighs drive the lower legs in freestyle swimming. This swimming method efficiently utilizes tail waves to achieve forward propulsion. Biomimetic robotic fish are categorized based on their actuation methods: traditional electro-hydraulic / pneumatic actuation and intelligent material actuation. Currently, most biomimetic fish still employ a series motor drive system, with motors positioned at the rotation axis of the tail's rotating joints. Typically, 2-4 joint motors are connected in series to achieve the tail's undulating shape. Summary of the Invention

[0004] The current driving methods for biomimetic robotic fish have significant problems. As the fish grows larger, the weight of the oscillating joints and the tail increases with the weight of the motor. Furthermore, the motor's left-right oscillation requires continuous start-stop-reverse-start-stop cycles, necessitating a low moment of inertia in the motor itself, making it difficult to achieve high-power oscillations. Currently, achieving frequencies above 2Hz is quite challenging for most motors. Besides series-connected motors, methods using full-circumference rotation, such as crank-connecting rod mechanisms and cam transmission mechanisms, can achieve tail oscillation. However, these mechanisms inherently suffer from the inability to change the tail's phase difference, and the assembled tail exhibits a fixed bend rather than a natural posture, resulting in a highly inconsistent appearance with the actual fish.

[0005] To address the issues that ordinary series motor joints cannot achieve high-frequency oscillation and that crank-connecting rod mechanisms and cam transmission mechanisms cannot achieve natural posture and cannot adjust phase difference, this invention proposes a crank-connecting rod driven bionic fishtail mechanism.

[0006] To solve the above problems, the present invention is achieved through the following technical solution:

[0007] This invention proposes a crank-connecting rod driven bionic fishtail mechanism, characterized by comprising a crank-connecting rod drive mechanism, a support frame 1, a tension / compression sensor 2, a conversion frame 3, a tripod 4, a waterproof motor 7, and a vertical support plate 6. The support frame 1 is connected to the tension / compression sensor 2. One end of the tripod 4 is connected to the conversion frame 3. The conversion frame 3 is connected through the tension / compression sensor 2 and positioned on the side of the tripod 4 closest to the sensor. A central cylindrical beam is located on the upper part of the end of the tripod 4 furthest from the conversion frame 3. The central cylindrical beam and the shaft... The bearing 5 is interference-fitted and securely connected to the support frame 1. The lower end of the tripod 4 is connected to the upright support plate 6. The front end of the housing of the waterproof motor 7 and the upright support plate 6 are each connected to the rigid frame. The waterproof motor 7 is connected to a crank-connecting rod drive mechanism. The crank-connecting rod drive mechanism is located inside the rigid frame. The crank-connecting rod drive mechanism has a crank disc inside. A pull rope is connected around the crank disc. The pull rope is guided by a pulley and then connected to the fishtail joint structure, so that the fishtail joint structure is fixedly connected to the rigid frame.

[0008] Preferably, in the crank-connecting rod driven bionic fishtail mechanism of the present invention, the rigid frame is formed by sequentially connecting the first horizontal plate 10 with the first vertical plate 11, the second horizontal plate 26 and the second vertical plate 31, and the vertical support plate 6 is connected to the first horizontal plate 10 of the rigid frame.

[0009] Further preferably, in the crank-connecting rod driven bionic fishtail mechanism of the present invention, the crank-connecting rod driven bionic fishtail mechanism includes at least a first crank plate 27, a second crank plate 28, and a third crank plate 29. The first crank plate 27, the second crank plate 28, and the third crank plate 29 are axially positioned and fixed between the first horizontal plate 10 and the second horizontal plate 26 of the rigid frame structure by a crank shaft 30 retaining spring and a concentric bearing. The waterproof motor 7 is connected via the crank shaft 30. The crank-connecting rod drive mechanism drives and rotates the first crank plate 27, the second crank plate 28, and the third crank plate 29; at least the first crank plate 27, the second crank plate 28, and the third crank plate 29 are respectively surrounded by at least the first pull rope 32, the second pull rope 33, and the third pull rope 34; the first pull rope 32, the second pull rope 33, and the third pull rope 34 are guided by pulleys and then fastened to the fishtail joint structure by the first, second, and third tensioning bolts 42, 40, and 41.

[0010] More preferably, the crank-connecting rod drive mechanism is configured as follows: the waterproof motor 7 is connected to the first crank 13 of the crank-connecting rod drive mechanism via the coupling 12; both ends of the coupling 12 are concentrically connected to the shaft of the waterproof motor 7 and the first crank 13 respectively with set screws; the first bearing 14 and the first connecting rod 15 hold the first crank 13 tightly; the first baffle 16 is fastened to the first crank 13; the first crank 13 and the second crank 18 are concentrically connected with clearance; the second stop 17 and the second crank 18 are fastened to each other, and the second crank 18 is fastened to the lower second baffle 20; the second bearing 19 and the second connecting rod 21 hold the second crank 18 tightly; the third crank 22 and the second crank 18... The concentric gap connection is used. The third stop 23 is fastened to the third crank 22. The third bearing 24 and the third connecting rod 25 hold the third crank 22 tightly. The first connecting rod 15 and the first crank disc 27 are axially limited by the cylindrical gap cooperation with the axial retaining spring. The second connecting rod 21 and the second crank disc 28 are axially limited by the cylindrical gap cooperation with the axial retaining spring. The third connecting rod 25 and the third crank disc 29 are axially limited by the cylindrical gap cooperation with the axial retaining spring.

[0011] More preferably, for the crank-connecting rod driven bionic fishtail mechanism, the fastening connection is a bolt fastening connection, and the clamping is a bolt clamping clamping.

[0012] More preferably, for the crank-connecting rod driven bionic fish tail mechanism, the rear end of the waterproof motor 7 housing is connected to a watertight joint; preferably, there are at least two watertight joints, including a first watertight joint 8 and a second watertight joint 9.

[0013] More preferably, for the crank-connecting rod driven bionic fishtail mechanism, when the motor drives the crank to rotate, the first crank 13 drives the first baffle 16 to rotate at a certain angle, and then the first baffle 16 contacts the second baffle 17 and starts to drive the second crank 18 to rotate. The second baffle 20 on the second crank 18 rotates at a certain angle and then contacts the third baffle 23 on the third crank 22 and drives the third crank 22 to rotate. In this way, the first crank 13 drives the second crank 18 to rotate, and the second crank 18 drives the third crank 22 to rotate.

[0014] More preferably, for the crank-connecting rod driven bionic fish tail mechanism, the fish tail joint structure includes a fixed joint end 35, a joint and a fish tail 39, wherein one end of the fixed joint end 35 is detachably connected to the second vertical plate 31, and the other end is detachably connected to the joint, and the fixed joint end 35 is detachably connected to the fish tail through the joint.

[0015] More preferably, for the crank-connecting rod driven bionic fish tail mechanism, the joint includes at least a first joint 36, a second joint 37, and a third joint 38. One end of the first joint 36 is detachably connected to the fixed joint end 35. The first joint 36, the second joint 37, and the third joint 38 are detachably connected in sequence. The third joint 38 is detachably connected to the fish tail 39 of the fish tail joint structure.

[0016] More preferably, for the crank-connecting rod driven bionic fish tail mechanism, the first pull rope 32, the second pull rope 33 or the third pull rope 34 are fastened to the fish tail 39 by tensioning bolts.

[0017] More preferably, in the crank-connecting rod driven bionic fish tail mechanism, the second pull rope 33 is guided by a pulley, passes through the first joint 36 and the second joint 37 in sequence, and is then connected to the fish tail 39.

[0018] More preferably, in the crank-connecting rod driven bionic fish tail mechanism, the third pull rope 34 passes through the pulley guide hole, passes through the first joint 36, and is then connected to the fish tail 39.

[0019] More preferably, for the crank-connecting rod driven bionic fish tail mechanism, the first pull rope 32, the second pull rope 33 or the third pull rope 34 are fastened to the fish tail 39 by tensioning bolts.

[0020] More preferably, for the crank-connecting rod driven bionic fish tail mechanism, the number of crank-connecting rods formed by the crank and connecting rod is 1-10 sets, preferably 3-10 sets.

[0021] More preferably, for the crank-connecting rod driven bionic fish tail mechanism, the characteristic is that adjusting the positions of the first stop 16, the second stop 17, the second stop 20, and the third stop 23 can achieve different phase differences.

[0022] More preferably, for the crank-connecting rod driven bionic fish tail mechanism, the characteristic is that when the motor is not rotating, all the baffles and all the blocks are not in contact, the crank joint is directly in a free state, and the fish tail can achieve a natural bending or straightening state.

[0023] In other words, in the biomimetic fish tail mechanism of the present invention, different phase differences can be adjusted by adjusting the positions of the first baffle, the second block, the second baffle, and the third block. Furthermore, when the motor is not rotating, the baffle and the block are not in contact, the crank joint is directly in a free state, and the fish tail can be naturally bent or straightened.

[0024] According to the crank-connecting rod driven bionic fish tail mechanism of the present invention, the phase difference of the fish tail can be adjusted to achieve the effect of the fish tail wave, in which the front joint drives the rear joint.

[0025] The beneficial effects of this invention are:

[0026] 1. This invention can achieve high-frequency fish tail swaying;

[0027] 2. This invention can achieve the natural extended state of the fish tail when at rest;

[0028] 3. This invention can realize the phase difference of the fish tail and the phase difference can be adjusted, so that the fish tail joint can swing in a highly efficient swimming mode according to the fish body. Attached Figure Description

[0029] Figure 1 This is an overall structural diagram of the crank-connecting rod driven bionic fish tail structure of the present invention;

[0030] Figure 2a This is a three-dimensional structural diagram of the first and second baffles of the crank-connecting rod driven bionic fish tail mechanism of the present invention.

[0031] Figure 2b for Figure 2a A front view of the first and second baffles;

[0032] Figure 2c for Figure 2a Top view of the first and second baffles;

[0033] Figure 2d for Figure 2c Cross-sectional view in the cc direction;

[0034] Figure 3a This is a front view of the structure of the second and third stops in the crank-connecting rod driven bionic fish tail mechanism of the present invention;

[0035] Figure 3b This is a top view of the structure of the second and third stops in the crank-connecting rod driven bionic fish tail mechanism of the present invention;

[0036] Figure 3c This is a left view of the structure of the second and third stops in the crank-connecting rod driven bionic fish tail mechanism of the present invention;

[0037] Figure 4a This is a three-dimensional structural diagram of the first crank structure in the crank-connecting rod driven bionic fish tail mechanism of the present invention.

[0038] Figure 4b for Figure 4a A front view of the first crank structure;

[0039] Figure 4c for Figure 4a A bottom view of the first crank structure;

[0040] Figure 4d for Figure 4a Top view of the first crank structure;

[0041] Figure 4e for Figure 4b A cross-sectional view along the AA direction in the first crank structure;

[0042] Figure 4f for Figure 4a Left view of the first crank structure;

[0043] Figure 4g for Figure 4a Rear view of the first crank structure;

[0044] Figure 4h for Figure 4f A cross-sectional view of the structure shown in the BB direction;

[0045] Figure 5a This is a schematic diagram of the three-dimensional structure of the second crank in the crank-connecting rod driven bionic fish tail mechanism of the present invention;

[0046] Figure 5b for Figure 5a A front view of the second crank structure;

[0047] Figure 5c for Figure 5b Cross-sectional view of the second crank structure in the BB direction;

[0048] Figure 5d for Figure 5b A cross-sectional view of the second crank structure in the AA direction;

[0049] Figure 5e for Figure 5a A bottom view of the second crank structure.

[0050] Figure 6a This is a front view of the third crank in the crank-connecting rod driven bionic fish tail mechanism of the present invention;

[0051] Figure 6b This is a bottom view of the third crank in the crank-connecting rod driven bionic fish tail mechanism of the present invention;

[0052] Figure 6c This is a top view of the third crank in the crank-connecting rod driven bionic fish tail mechanism of the present invention;

[0053] Figure 6d for Figure 6a A cross-sectional view of the structure shown in the AA direction;

[0054] Figure 6e This is a left view of the third crank in the crank-connecting rod driven bionic fish tail mechanism of the present invention;

[0055] Figure 6f for Figure 6e Cross-sectional view of the structure in the BB direction shown;

[0056] Figure 7 for Figure 1 A magnified view of a portion of the crank-connecting rod mechanism in the bionic fishtail mechanism driven by the crank-connecting rod;

[0057] Figure 8a This is a schematic diagram of the fish tail in the crank-connecting rod driven bionic fish tail mechanism of the present invention, in which the fish tail is not driven by the motor and is in a naturally straightened or bent state.

[0058] Figure 8b This is a schematic diagram of the fish tail in the crank-connecting rod driven bionic fish tail mechanism of the present invention, which is driven by a motor and is in a bending and swinging state.

[0059] Explanation of reference numerals in the attached figures

[0060] 1. Support frame; 2. Tension / compression sensor; 3. Conversion frame; 4. Tripod; 5. Bearing; 6. Vertical support plate; 7. Waterproof motor; 8. First watertight connector; 9. Second watertight connector; 10. First horizontal plate; 11. First vertical plate; 12. Coupling; 13. First bearing shell; 14. First connecting rod; 15. First baffle; 16. Second baffle block; 17. Second crank; 18. Second bearing shell; 19. Second baffle; 20. Second connecting rod; 21. Third crank; 22. Third baffle block; 23. Third bearing shell; 24. Third connecting rod; 25. Second horizontal plate; 26. First crank disc; 27. Second crank disc; 28. Third crank disc; 29. ​​Crank shaft; 30. Second vertical plate; 31. First pull rope; 32. Second pull rope; 33. Third pull rope; 34. Fixed joint end; 35. First joint; 36. Second joint; 37. Third joint; 38. Fish tail; 39. First tension bolt; 40. Second tension bolt; 41. Third tension bolt; 42. Detailed Implementation

[0061] The technical solution of the crank-connecting rod driven bionic fishtail mechanism of the present invention will be further described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are merely exemplary examples of the present invention, and not all embodiments. The directional terms such as "left," "right," "middle," "center," "upper," "lower," "top," and "bottom" used therein are only for the convenience of explaining the structure and working principle of the present invention in conjunction with the accompanying drawings, and should not be regarded as a limitation of the present invention. 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.

[0062] like Figure 1As shown, this invention provides a crank-connecting rod driven bionic fishtail mechanism, including a crank-connecting rod drive mechanism, a support frame 1, a tension / compression sensor 2, a conversion frame 3, a tripod 4, a waterproof motor 7, and a vertical support plate 6. The tension / compression sensor 2 is bolted to the support frame 1. The right end of the tripod 4 is bolted to the conversion frame 3, which is connected through the tension / compression sensor 2 and positioned to the left of the sensor. The upper left end of the tripod 4 has a central cylindrical beam, which is interference-fitted with a bearing 5. The bearing 5 is bolted to the support frame 1. The lower end of the tripod 4 is bolted to the vertical support plate 6. The invention also includes a waterproof motor 7 connected to the crank-connecting rod mechanism. The crank-connecting rod mechanism has a crank disc, around which a pull rope is wound. The pull rope is guided by pulleys and connected to the fishtail joint structure, thereby fixing the fishtail joint structure to the rigid frame.

[0063] In a preferred embodiment, the first horizontal plate 10, the first vertical plate 11, the second horizontal plate 26, and the second vertical plate 31 are bolted together in sequence to form a rigid frame, and the vertical support plate 6 is connected to the first horizontal plate 10 of the rigid frame.

[0064] In a preferred embodiment, the top of the waterproof motor 7 housing is threaded with a first watertight connector 8 and a second watertight connector 9.

[0065] In a specific embodiment of the biomimetic fish tail mechanism of the present invention, the first crank structure, the second crank structure, and the third crank structure are as follows: Figures 4a-4h , Figures 5a-5e , Figures 6a-6f As shown; where, Figures 4a-4h These are, respectively, a perspective view, a front view, a bottom view, a top view, a cross-sectional view along the AA direction, a right view, a rear view, and a cross-sectional view along the BB direction of the first crank structure in the bionic fish tail mechanism of the present invention; Figures 5a-5e These are, respectively, a perspective view, a front view, a cross-sectional view along the BB direction, a cross-sectional view along the AA direction, and a bottom view of the second crank structure in the bionic fish tail mechanism of the present invention; Figures 6a-6f These are, respectively, the front view, bottom view, top view, AA-direction cross-sectional view, right view, and BB-direction cross-sectional view of the third crank in the bionic fishtail mechanism of the present invention.

[0066] In a preferred embodiment, the crank-connecting rod drive mechanism includes at least a first crank plate 27, a second crank plate 28, and a third crank plate 29. The first crank plate 27, the second crank plate 28, and the third crank plate 29 are axially positioned and fixed between the first horizontal plate 10 and the second horizontal plate 26 of the rigid frame structure via a crank shaft 30 retaining spring and a concentric bearing. The waterproof motor 7 drives the first crank plate 27, the second crank plate 28, and the third crank plate 29 to rotate via the crank-connecting rod drive mechanism. At least a first pull rope 32, a second pull rope 33, and a third pull rope 34 are respectively connected around the first crank plate 27, the second crank plate 28, and the third crank plate 29. The first pull rope 32, the second pull rope 33, and the third pull rope 34 are guided by pulleys and then fastened to the fishtail joint structure by tension bolts 42, 40, and 41.

[0067] Specifically, such as Figure 7 As shown, Figure 7 for Figure 1 A partial enlarged view of the crank-connecting rod mechanism in the bionic fishtail mechanism driven by the crank-connecting rod ( Figure 1 (Enlarged view of the connection relationship of the three crank components shown in A); The crank-connecting rod drive mechanism is configured as follows: The waterproof motor 7 is connected to the first crank 13 of the crank-connecting rod drive mechanism through the coupling 12; the two ends of the coupling 12 are respectively concentrically connected to the shaft of the waterproof motor 7 and the first crank 13 with set screws; the first bearing 14 and the first connecting rod 15 are bolted to the first crank 13; the first baffle 16 and the first crank 13 are bolted together; the first crank 13 and the second crank 18 are concentrically connected with a clearance; the second stop 17 and the second crank 18 are bolted together; and the second crank (18) is bolted to the second baffle (20) below; the second bearing 19 and the second connecting rod 21 are bolted to the second crank 18; the third crank 22 and the second crank 18 are concentrically connected with a clearance. The third stop 23 is bolted to the third crank 22. The third bearing 24 and the third connecting rod 25 are fastened to the third crank by bolts. The first connecting rod 15 and the first crank disc 27 are axially limited by a cylindrical clearance fit with a retaining spring. The second connecting rod 21 and the second crank disc 28 are axially limited by a cylindrical clearance fit with a retaining spring. The third connecting rod 25 and the third crank disc 29 are axially limited by a cylindrical clearance fit with a retaining spring.

[0068] The crank shaft 30, the first crank disc 27, the second crank disc 28, and the third crank disc 29 are axially positioned and concentrically supported by retaining rings on the first horizontal plate 10 and the second horizontal plate 26 of the rigid frame structure; the waterproof motor 7 drives and rotates the first crank disc 27, the second crank disc 28, and the third crank disc 29 through the crank connecting rod and other components formed by the crank connecting rod and other components.

[0069] In one specific implementation, the fish tail joint structure includes a fixed joint end 35, a joint, and a fish tail 39. One end of the fixed joint end 35 is detachably connected to the second vertical plate 31, and the other end is detachably connected to the joint. The fixed joint end 35 is detachably connected to the fish tail through the joint.

[0070] Specifically, the first pull rope 32, the second pull rope 33, and the third pull rope 34 are respectively connected to the first crank plate 27, the second crank plate 28, and the third crank plate 29; one end of the fixed joint end 35 is bolted to the second vertical plate 31, and the other end is bolted to the first joint 36; both ends of the second joint 37 are bolted to the first joint 36 and the third joint 38 respectively; and both ends of the third joint 38 are bolted to the second joint 37 and the fish tail 39 respectively.

[0071] The first pull rope 32 passes through the first joint 36, the second joint 37, and the third joint 38 in sequence via the pulley guide, and is then fastened by the third tension bolt 42.

[0072] The second pull rope 33 passes through the hole in sequence via the pulley guide, through the first joint 36 and the second joint 37, and is then fastened by the second tension bolt 41.

[0073] The third pull rope 34 passes through the pulley guide hole, passes through the first joint 36, and is then fastened by the first tension bolt 40.

[0074] In one specific implementation, the first pull rope 32, the second pull rope 33, or the third pull rope 34 are fastened to the fish tail 39 by tensioning bolts.

[0075] It should be noted that the number of crank-connecting rods formed by the crank and connecting rod is 1-10 sets, preferably 3-10 sets.

[0076] In a specific embodiment of the bionic fish tail mechanism of the present invention, the structures of the first and second stop plates, as well as the second and third stop blocks, are as follows: Figures 2a-2d , as well as Figures 3a-3c As shown. Among them, Figures 2a-2d These are, respectively, a three-dimensional structural diagram, a front view, a top view, and a cross-sectional schematic diagram in the cc direction of the first and second plates of a specific biomimetic fish tail mechanism of the present invention. Figures 3a-3c These are, respectively, the front view, top view, and right view of the second and third blocks in the bionic fish tail mechanism of the present invention.

[0077] like Figure 7 , Figure 8a and 8bAs shown, the motor drives the first crank 13 to rotate via a coupling. Before the first baffle 16 and the second stop 17 contact, the motor only affects the rotation of the first crank 13. After the first crank 13 drives the first baffle 16 to rotate and contacts the second stop 17 on the second crank 18, the second crank 18 begins to experience rotational torque. Similarly, after the second crank 18 drives the second baffle 20 to rotate and contacts the third stop 23 on the third crank 22, the third crank 22 begins to rotate after receiving rotational torque.

[0078] In practice, after the device of the present invention is installed, the positions of the baffle and block of the fish tail are adjusted according to the actual required phase difference. The first crank, the second crank, and the third crank rotate left and right in sequence according to the structural principle of the present invention, thereby realizing the sequential swinging of the three joints of the rear end of the fish tail, thus realizing the phase difference of the fish tail, that is, realizing the fish tail wave effect of the front end joint driving the rear end joint. In the case of realizing the phase difference, a natural straight state without phase difference can also be realized. The natural straight state is realized as follows: when the motor drives the crank to rotate, the first crank 13 drives the first baffle 16 to rotate a certain angle, and then the first baffle 16 contacts the second block 17 and then starts to drive the second crank 18 to rotate. The second baffle 20 on the second crank 18 rotates a certain angle with the second crank 18 and then contacts the third block 23 on the third crank 22 and drives the third crank 22 to rotate. In this way, the first crank 13 drives the second crank 18 to rotate, and the second crank 18 drives the third crank 22 to rotate. Adjusting the positions of the first baffle 16, the second baffle 17, the second baffle 20, and the third baffle 23 allows for different phase differences to be adjusted. When not rotating, and the baffles and baffles are not in contact, the fish tail is in a free state (the free state of the fish tail can be either bent or straight). For example... Figure 8a As shown, before the first baffle 16 and the second baffle 17, as well as the second baffle 20 and the third baffle 23, come into contact, the fish tail is naturally straight; as Figure 8b As shown, after the first baffle 16 and the second baffle 17, as well as the second baffle 20 and the third baffle 23 come into contact, the three joints are driven by the rotation of the motor, causing the fishtail mechanism to bend and swing.

[0079] The specific process for adjusting different phase differences is explained as follows: The first baffle 16 can be adjusted in angle on the first crank 13 by tightening bolts; the second baffle 17 can be adjusted in angle on the second crank 18 by tightening bolts; the second baffle 20 can be adjusted in angle on the second crank 18 by tightening bolts; and the third baffle 23 can be adjusted in angle on the third crank 22 by tightening bolts. The changes in the positions of the first baffle 16 and the second baffle 17 can alter the time and angle at which the first crank 13 drives the second crank 18 to rotate; the changes in the positions of the second baffle 20 and the third baffle 23 can alter the time and angle at which the second crank 18 drives the third crank 29 to rotate. This allows for the adjustment of different phase differences.

[0080] In other words, the biomimetic fish tail structure of this invention can achieve different phase differences by adjusting the positions of the first baffle 16, the second baffle 17, the second baffle 20, and the third baffle 23. When the motor is not rotating, all the baffles and all the baffles are not in contact, the crank joint is directly in a free state, and the fish tail can be naturally bent or straightened.

[0081] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. For example, the above embodiments only describe the fishtail with 3 joints (3 crank-connecting rod structures) in detail, but it can actually be adjusted to n (n joints, where n takes values ​​from 1 to 10) joints (n crank-connecting rod structures). Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A crank-connecting rod driven biomimetic fish tail mechanism, characterized in that, The system includes a crank-connecting rod drive mechanism, a support frame (1), a tension / compression sensor (2), a conversion frame (3), a tripod (4), a waterproof motor (7), and a vertical support plate (6). The tension / compression sensor (2) is connected to the support frame (1), and one end of the tripod (4) is connected to the conversion frame (3). The conversion frame (3) is connected through the tension / compression sensor (2) and is located on the side of the tension / compression sensor (2) near the tripod (4). A central cylinder is provided on the upper part of the end of the tripod (4) away from the conversion frame (3). A crossbeam, the middle cylindrical crossbeam and the bearing (5) are interference-fitted together, the bearing (5) is fastened to the support frame (1), and the lower end of the tripod (4) is connected to the vertical support plate (6); the front end of the housing of the waterproof motor (7) and the vertical support plate (6) are each connected to the rigid frame; the waterproof motor (7) is connected to a crank-connecting rod drive mechanism; the crank-connecting rod drive mechanism is set inside the rigid frame, and a crank disc is provided inside the crank-connecting rod drive mechanism. A pull rope is connected around the crank disc, and the pull rope is guided by a pulley. The tail joint structure is then connected to the fishtail joint structure, thereby fixing the fishtail joint structure to the rigid frame; the crank-connecting rod drive mechanism is provided with at least a first crank plate (27), a second crank plate (28), and a third crank plate (29), the first crank plate (27), the second crank plate (28), and the third crank plate (29) are axially positioned and supported and fixed between the first horizontal plate (10) and the second horizontal plate (26) of the rigid frame structure by means of a crank shaft (30) retaining spring and a concentric bearing, and the waterproof motor (7) is connected to the fishtail joint structure. The crank-connecting rod drive mechanism drives and rotates the first crank plate (27), the second crank plate (28), and the third crank plate (29); at least the first crank plate (27), the second crank plate (28), and the third crank plate (29) are respectively surrounded by at least the first pull rope (32), the second pull rope (33), and the third pull rope (34); the first pull rope (32), the second pull rope (33), and the third pull rope (34) are respectively guided by pulleys and then fastened to the fishtail joint structure by tensioning bolts.

2. The crank-connecting rod driven bionic fishtail mechanism according to claim 1, wherein, The rigid frame is formed by sequentially connecting the first horizontal plate (10) with the first vertical plate (11), the second horizontal plate (26), and the second vertical plate (31), and the vertical support plate (6) is connected to the first horizontal plate (10) of the rigid frame.

3. The crank-connecting rod driven bionic fishtail mechanism according to claim 1 or 2, wherein, The crank-connecting rod drive mechanism is configured as follows: the waterproof motor (7) is connected to the first crank (13) of the crank-connecting rod drive mechanism via a coupling (12); both ends of the coupling (12) are concentrically connected to the shaft of the waterproof motor (7) and the first crank (13) respectively with set screws; the first bearing (14) and the first connecting rod (15) hug the first crank (13); the first baffle (16) is fastened to the first crank (13); the first crank (13) and the second crank (18) are concentrically connected with clearance; the second stop (17) and the second crank (18) are fastened together; and the second crank (18)... The second bearing (20) is fastened to the second baffle below. The second bearing (19) and the second connecting rod (21) hug the second crank (18). The third crank (22) and the second crank (18) are connected concentrically with a clearance. The third baffle (23) is fastened to the third crank (22). The third bearing (24) and the third connecting rod (25) hug the third crank (22). The first connecting rod (15) and the first crank disc (27) are axially limited by a cylindrical clearance with a retaining spring. The second connecting rod (21) and the second crank disc (28) are axially limited by a cylindrical clearance with a retaining spring. The third connecting rod (25) and the third crank disc (29) are axially limited by a cylindrical clearance with a retaining spring.

4. The crank-connecting rod driven bionic fishtail mechanism according to claim 3, wherein, The fastening connection is achieved by bolts, and the clamping is achieved by bolts.

5. The crank-connecting rod driven bionic fishtail mechanism according to claim 1 or 2, wherein, The waterproof motor (7) has a tight-fitting connector at the rear end of its housing.

6. The crank-connecting rod driven bionic fishtail mechanism according to claim 5, wherein, There are at least two watertight joints, including a first watertight joint (8) and a second watertight joint (9).

7. The crank-connecting rod driven bionic fishtail mechanism according to claim 3, wherein, When the motor drives the crank to rotate, the first crank (13) drives the first baffle (16) to rotate at a certain angle. After the first baffle (16) contacts the second baffle (17), it starts to drive the second crank (18) to rotate. The second baffle (20) on the second crank (18) contacts the third baffle (23) on the third crank (22) after the second crank (18) rotates at a certain angle. This drives the third crank (22) to rotate. In this way, the first crank (13) drives the second crank (18) to rotate, and the second crank (18) drives the third crank (22) to rotate.

8. The crank-connecting rod driven bionic fishtail mechanism according to claim 2, wherein, The fish tail joint structure includes a fixed joint end (35), a joint, and a fish tail (39). One end of the fixed joint end (35) is detachably connected to the second vertical plate (31), and the other end is detachably connected to the joint. The fixed joint end (35) is detachably connected to the fish tail through the joint.

9. The crank-connecting rod driven bionic fishtail mechanism according to claim 8, wherein, The joint includes at least a first joint (36), a second joint (37), and a third joint (38). One end of the first joint (36) is detachably connected to the fixed joint end (35). The first joint (36), the second joint (37), and the third joint (38) are detachably connected in sequence. The third joint (38) is detachably connected to the fish tail (39) of the fish tail joint structure.

10. The crank-connecting rod driven bionic fishtail mechanism according to claim 9, characterized in that, The first pull rope (32) is guided by a pulley and passes through the holes in sequence through the first joint (36), the second joint (37), and the third joint (38) before being connected to the fish tail (39).

11. The crank-connecting rod driven bionic fishtail mechanism according to claim 9, wherein, The second pull rope (33) is guided by a pulley, passes through the hole in sequence, passes through the first joint (36) and the second joint (37), and is then connected to the fish tail (39).

12. The crank-connecting rod driven bionic fishtail mechanism according to claim 9, wherein, The third pull rope (34) passes through the pulley guide hole, passes through the first joint (36), and is then connected to the fish tail (39).

13. The crank-connecting rod driven bionic fishtail mechanism according to claim 10, wherein, The first pull rope (32), the second pull rope (33) or the third pull rope (34) are fastened to the fish tail (39) by tensioning bolts.

14. The crank-connecting rod driven bionic fishtail mechanism according to claim 13, characterized in that, The number of crank-connecting rods formed by the crank and connecting rod is 1-10.

15. The crank-connecting rod driven bionic fishtail mechanism according to claim 14, characterized in that, The number of crank-connecting rods formed by the crank and connecting rod is 3-10.

16. The crank-connecting rod driven bionic fishtail mechanism according to claim 3, characterized in that, Adjusting the positions of the first baffle (16), the second baffle (17), the second baffle (20), and the third baffle (23) can achieve different phase differences.

17. The crank-connecting rod driven bionic fishtail mechanism according to claim 3, characterized in that, When the motor is not rotating, all the baffles and blocks are not in contact, the crank joint is in a free state, and the fish tail can be naturally bent or straightened.

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