A bistable biomimetic robotic fish

Abstract

The application discloses a kind of bistable biomimetic robot fish, it is related to biomimetic robot fish technical field, including fish body, first driving device, bistable structure and fish tail, first driving device is set in fish body, bistable structure has two equilibrium states, the output of first driving device is connected with one end of bistable structure, first driving device can drive bistable structure swing around first axis and change from one equilibrium state to another equilibrium state, the other end of bistable structure is connected with fish tail, and bistable structure swing around first axis can drive fish tail swing.The fish body tail of the present application is provided with the bistable structure, and the volume of the bistable structure is small, has two stable equilibrium states, can be switched between the two states quickly under the excitation of driving mechanism, and releases the elastic potential energy stored in the process, produces explosive movement, can quickly drive fish tail swing, and then makes fish body swim quickly.

Description

Technical Field

[0001] This invention relates to the field of biomimetic robotic fish technology, and in particular to a bistable biomimetic robotic fish. Background Technology

[0002] Bionic robotic fish, especially those that borrow from the BCF (Body and / or Caudal Fin propulsion) propulsion mode of fish, have become an important research direction in fields such as marine resource exploration, environmental monitoring, and national defense security. Currently, the driving methods of bionic robotic fish are mainly divided into two categories: rigid actuation and soft actuation.

[0003] Rigid actuators typically use a motor in conjunction with a rigid linkage mechanism to drive the tail fin's oscillation. These systems are complex, heavy, and have low energy conversion efficiency. Furthermore, their motion differs significantly from the graceful oscillations of real fish, making it difficult to balance propulsion efficiency and maneuverability, thus limiting overall swimming performance. Flexible actuators, on the other hand, better simulate the graceful movements of fish, effectively reducing drag and exhibiting higher motion efficiency in specific scenarios. However, these soft actuators usually require a drive structure on the side, generally suffering from low output force, slow response speed, and insufficient thrust. This makes it difficult for biomimetic robotic fish to achieve high-speed movement and instantaneous acceleration, and their maneuverability fails to meet the demands of practical engineering applications. Summary of the Invention

[0004] The purpose of this invention is to provide a bistable biomimetic robotic fish to solve the problems existing in the prior art, thereby reducing the weight of the drive structure while achieving high-speed movement and instantaneous acceleration.

[0005] To achieve the above objectives, the present invention provides the following solution: This invention provides a bistable biomimetic robotic fish, comprising a fish body, a first driving device, a bistable structure, and a fish tail. The first driving device is disposed within the fish body. The bistable structure has two equilibrium states. The output of the first driving device is connected to one end of the bistable structure. The first driving device can drive the bistable structure to oscillate around a first axis and change from one equilibrium state to another. The other end of the bistable structure is connected to the fish tail. The oscillation of the bistable structure around the first axis can drive the fish tail to oscillate.

[0006] In one embodiment, the bistable structure is made of an elastic material, and the bistable structure connected to the fish tail has elastic deformation.

[0007] In one embodiment, the bistable structure includes a first connecting plate, a second connecting plate, and a third connecting plate. The middle part of the first connecting plate is fixedly connected to the output component of the first driving device. One end of the first connecting plate is fixedly connected to one end of the second connecting plate, and the other end of the first connecting plate is fixedly connected to one end of the third connecting plate. The other end of the second connecting plate is a first end with a first connection position. The other end of the third connecting plate is a second end with a second connection position. The first connecting plate, the second connecting plate, and the third connecting plate are all made of elastic material. The first connection position and the second connection position are both connected to the fish tail. The first connecting plate, the second connecting plate, and the third connecting plate connected to the fish tail all have elastic deformation.

[0008] In one embodiment, the distance between the first connection position and the second connection position in the first direction can be adjusted and connected to the fish tail, and the first direction is parallel to the first axis.

[0009] In one embodiment, the bistable structure is made of spring steel or polyester.

[0010] In one embodiment, a thin film is further included, which is fixedly connected to the bistable structure and capable of covering the space between the second connecting plate and the third connecting plate.

[0011] In one embodiment, the film is a silicone film, which is wrapped around the second connecting plate and the third connecting plate and covers the space between them.

[0012] In one embodiment, the fish body includes a head, a middle section of the body, and a rear section. The head is fixedly connected to one end of the middle section of the body, and the rear section of the body is rotatably connected to the other end of the middle section of the body about a second axis. The second axis is parallel to the first axis. The first driving device is fixedly disposed in the rear section of the body. A limiting groove is provided at the end of the rear section of the body near the bistable structure. The portion of the bistable structure away from the tail is placed in the limiting groove and can swing within the limiting groove.

[0013] In one embodiment, the fish also includes a second drive device and two pectoral fins. The second drive device is disposed in the middle section of the fish body. The output of the second drive device is connected to the two pectoral fins. The two pectoral fins extend out of the middle section of the fish body. The second drive device can drive the two pectoral fins to rotate around a third axis. The plane passing through the first axis and the second axis is the first plane. The third axis is perpendicular to the first plane.

[0014] In one embodiment, a third driving device is also included, the output of which is fixedly connected to the rear section of the fish, and the third driving device is capable of driving the rear section of the fish to rotate about the second axis.

[0015] The present invention achieves the following technical effects compared to the prior art: This invention discloses a bistable biomimetic robotic fish. The bistable structure set at the tail of the fish is small in size and has two stable equilibrium states. Under the excitation of the first driving device, the bistable structure can quickly switch between these two equilibrium states and release the stored elastic potential energy in the process, generating explosive motion. It can quickly drive the tail to swing, thereby enabling the fish to swim quickly. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a cross-sectional view of a bistable biomimetic robotic fish according to some embodiments of the present invention. Figure 2 This is a schematic diagram of the power mechanism of the bistable biomimetic robotic fish in some embodiments of the present invention; Figure 3 This is a schematic diagram of the third drive device of the bistable bionic robotic fish in some embodiments of the present invention. Figure 4 This is a schematic diagram of the drive mechanism of the bistable biomimetic robotic fish in some embodiments of the present invention. Figure 5 This is a front view of the bistable structure of the present invention when the first and second connection positions are not connected; Figure 6 for Figure 5 Right view of the bistable structure in the image; Figure 7 A schematic diagram showing the connection between the first and second connection positions of the bistable structure of the present invention; Figure 8 A front view showing the connection between the first and second connection positions of the bistable structure of the present invention; Figure 9 A top view showing the connection between the first and second connection positions of the bistable structure of the present invention; Figure 10This represents the maximum deflection value of the bistable biomimetic robotic fish structure of the present invention under different preload distances; Figure 11 The deflection curves of the bistable biomimetic robotic fish structure of the present invention under different preload distances are shown. Figure 12 This is a comparison diagram of the average force values ​​at different frequencies of the bistable and non-bistable tails of the bistable bionic robotic fish of the present invention. Figure 13 This is a comparison diagram of the force value range at different frequencies of the bistable and non-bistable tails of the bistable bionic robotic fish of the present invention; Figure 14 Force-time curves of the bistable and non-bistable tails of the bistable biomimetic robotic fish of this invention; In the diagram: 1. Fish body; 2. First drive unit; 3. Bistable structure; 31. First connecting plate; 32. Second connecting plate; 33. Third connecting plate; 4. Fish tail; 5. Fish head; 6. Midsection of fish body; 7. Rear section of fish body; 8. Second drive servo; 9. First gear; 10. Second gear; 11. Pectoral fin; 12. Third drive servo; 13. First drive servo; 14. Drive arm; 15. Drive support arm; 16. First mounting bracket; 17. Second mounting bracket; 18. Mounting platform; 19. Limiting groove; 20. Connecting bracket; 21. Baffle; 22. Fifth axis; 23. Sixth axis; 24. Seventh axis; 25. Eighth curve. Detailed Implementation

[0018] 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.

[0019] The purpose of this invention is to provide a bistable biomimetic robotic fish to solve the problems existing in the prior art, so as to reduce the weight of the drive structure while achieving high-speed movement and instantaneous acceleration.

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1-4As shown, this invention provides a bistable biomimetic robotic fish, comprising a fish body 1, a first driving device 2, a bistable structure 3, and a tail 4. The first driving device 2 is disposed within the fish body 1. The bistable structure 3 has two equilibrium states. The output of the first driving device 2 is connected to one end of the bistable structure 3. The first driving device 2 can drive the bistable structure 3 to oscillate around a first axis and change from one equilibrium state to another. The other end of the bistable structure 3 is connected to the tail 4. The oscillation of the bistable structure 3 around the first axis can drive the tail 4 to oscillate. The bistable structure 3 disposed at the tail of the fish body 1 is small in size and has two stable equilibrium states. Under the excitation of the first driving device 2, it can quickly switch between these two equilibrium states and release stored elastic potential energy in the process, generating explosive motion, which can quickly drive the tail 4 to oscillate, thereby enabling the fish body 1 to swim rapidly.

[0022] In one embodiment, the bistable structure 3 is made of an elastic material and is connected to the fish tail 4. The bistable structure 3, made of an elastic material, exhibits elastic deformation, which enables the fish tail 4 to swing rapidly. The bistable structure 3 has elastic deformation in both equilibrium states and possesses energy to recover from deformation. Under the oscillation excitation of the first driving device 2, it generates an inter-well jump, instantaneously changing from one equilibrium state to another, rapidly releasing energy, thereby causing the fish tail 4 to swing, thus achieving high-speed movement and instantaneous acceleration of the biomimetic fish.

[0023] In one embodiment, the bistable structure 3 includes a first connecting plate 31, a second connecting plate 32, and a third connecting plate 33. The middle part of the first connecting plate 31 is fixedly connected to the output component of the first driving device 2. One end of the first connecting plate 31 is fixedly connected to one end of the second connecting plate 32, and the other end of the first connecting plate 31 is fixedly connected to one end of the third connecting plate 33. The other end of the second connecting plate 32 is the first end, which has a first connection position. The other end of the third connecting plate 33 is the second end, which has a second connection position. The first connecting plate 31, the second connecting plate 32, and the third connecting plate 33 are all made of elastic material. The first connection position and the second connection position are both connected to the fish tail 4. The first connecting plate 31, the second connecting plate 32, and the third connecting plate 33 connected to the fish tail 4 all have elastic deformation.

[0024] In a more specific embodiment, one end of the first connecting plate 31 is connected to one end of the second connecting plate 32, and the other end of the first connecting plate 31 is connected to one end of the third connecting plate 33. The three are integrally formed to create a bistable structure 3. The first connecting plate 31, the second connecting plate 32, and the third connecting plate 33 connected to the fish tail 4 all have elastic deformation, which results in prestress inside the bistable structure 3 composed of the first connecting plate 31, the second connecting plate 32, and the third connecting plate 33. Under the drive of the first driving device 2, it can generate explosive motion, causing the fish tail 4 to swing.

[0025] In some embodiments, the second connecting plate 32 and the third connecting plate 33 in the bistable structure 3 are symmetrical with respect to the horizontal centerline of the fish body 1, so that the second connecting plate 32 and the third connecting plate 33 deform synchronously during the jump. Since the second connecting plate 32 and the third connecting plate 33 in the bistable structure 3 are symmetrical with respect to the horizontal centerline of the fish body 1, there is concentrated stress at the connection points of the first connecting plate 31, the second connecting plate 32 and the third connecting plate 33 in the bistable structure 3. In this embodiment, the corners of the first connecting plate 31 and the second connecting plate 32, as well as the two corners of the first connecting plate 31 and the third connecting plate 33 are rounded to reduce the concentrated stress.

[0026] In one embodiment, the distance between the first connecting position and the second connecting position in the first direction is adjustable and they are connected to the fishtail 4, the first direction being parallel to the first axis. The distance between the first end and the second end in the first direction is adjustable, and adjusting the distance between the first connecting position and the second connecting position in the first direction can adjust the deformation amplitude of the bistable structure.

[0027] like Figures 5-11 As shown, Figure 5 The central axis of the first connecting plate 31 is the fifth axis 23, the central axis of the second connecting plate 32 is the sixth axis 22, the central axis of the third connecting plate 33 is the seventh axis 24, the edge lines of the second connecting plate 32 and the third connecting plate 33 are the eighth axis 25, L is the distance from the fifth axis 23 to the eighth axis 25, b is the distance between the first connecting position and the second connecting position, D is the distance between the sixth axis 22 and the seventh axis 24, and s is the cross-sectional width of the second connecting plate 32 or the third connecting plate 33. Figure 9 This indicates that the deformation of the edge at the end of the second connecting plate 32 or the third connecting plate 33 (the end furthest from the fish head) is the maximum deflection. .

[0028] Treating the second connecting plate 32 and the third connecting plate 33 as flexible beams with uniform cross-sections fixed at one end, a system is established. Figure 7 In the coordinate system shown, the length direction of the beam is consistent with the length directions of the second connecting plate 32 and the third connecting plate 33. The length direction of the beam is the locally varying coordinate axis x, and the bending direction of the beam is the globally fixed coordinate axis. The origin point O is located at the intersection of the sixth axis 22 and the fifth axis 23. Therefore, the structural deformation mainly occurs along... The bending deformation and torsional deformation about the x-axis of the shaft are governed by the Euler-Bernoulli beam deformation theorem: ; ; In the formula, Indicates along Bending deformation of the shaft, The x-axis represents torsional deformation; P represents the equivalent external force; M represents the equivalent external torque; E represents the elastic modulus of the material; G represents the shear modulus of the material; I represents the direction of the centerline of the section about the y-axis (the centerline of any section perpendicular to the x-axis of the second connecting plate 32 or the third connecting plate 33, parallel to the sixth axis 23, such as...). Figure 6 The moment of inertia (as shown in the figure) is given by J, which represents the torsional constant of the section; L0 represents the total length from the driving point (point A) to the end point involved in bending and torsional deformation. Where: ; ; ; ; in It is Poisson's ratio. The strain energy stored in the flexible beam is U, mainly the bending strain energy U along the v-axis. v and cross section U x Torsional strain energy: ; ; Total stored strain energy: ; The constraint relationship for connecting distance b can be obtained from the geometric relationship: ; By applying the minimum strain energy theorem, the curve of vx can be obtained by numerically solving the above formula, thus determining the shape of the bistable structure.

[0029] like Figures 9-10 As shown, with L=0.085m, s=0.01m, and w=0.5×10 -3 Under the condition of m, the deflection curves and maximum deflection in the range of b = 0.01~0.06m are shown. The changes are as follows. It can be seen that as the preload distance b increases, the deflection changes significantly, the maximum deflection increases, and the relationship is nonlinear. The larger the preload distance b, the greater the deflection, and the larger the amplitude of the fish tail swing. That is, a larger water-pushing displacement is generated in one swing cycle. At the same time, due to the increase of the preload distance b, the potential well of the bistable structure 3 is also deeper, and the energy released by the fish tail 4 in one swing is also greater. The swing speed of the fish tail 4 will increase, providing a greater instantaneous thrust (the forward thrust on the bionic fish generated by the swing of the fish tail).

[0030] Therefore, the greater the preload distance b, the greater the deformation of the bistable structure 3, and the greater the swing amplitude of the fishtail 4. Adjusting the preload distance b can change the swing amplitude of the fishtail 4. In one embodiment, the bistable structure 3 is made of spring steel or polyester. Elastic materials possess excellent tensile and flexural strength, meeting the stiffness requirements of the bistable structure 3 during repeated deformation, preventing structural failure due to weight reduction. The polyester material can be PET (polyethylene terephthalate) or PETG (polyethylene terephthalate-1,4-cyclohexanediol).

[0031] In one embodiment, a thin film is also included. The thin film is fixedly connected to the bistable structure 3 and can cover the second connecting plate 32 and the third connecting plate 33, as well as the space between them. The thin film is wrapped around the outside of the bistable structure 3 to cover the hollow part. The thin film can increase the water-facing area of ​​the tail and increase the forward thrust. At the same time, the shape of the wrapped thin film is similar to that of a fish body, which can increase the aesthetics of the shape.

[0032] In one embodiment, the film is a silicone film, which is wound around the space between the second connecting plate 32 and the third connecting plate 33. The silicone film has sufficient elasticity and a very small elastic modulus, so it hardly affects the transition process of the bistable structure 3. The film can also be a fluororubber film, which is resistant to water and acid and alkali corrosion, making it suitable for the actuation scenarios of underwater biomimetic devices.

[0033] In one embodiment, the fish body 1 includes a head 5, a mid-body section 6, and a rear section 7. The head 5 is fixedly connected to one end of the mid-body section 6, and the rear section 7 is rotatably connected to the other end of the mid-body section 6 around a second axis parallel to the first axis. A first driving device 2 is fixedly disposed within the rear section 7. A limiting groove 19 is provided at the end of the rear section 7 near the bistable structure 3, and the portion of the bistable structure 3 away from the tail 4 is placed within the limiting groove 19 and can swing within the limiting groove 19. The fish body 1 includes a head 5, a mid-body section 6, and a rear section 7. The fish body 1 is segmented, which can improve the simulation effect and enhance the swimming flexibility of the fish body 1. The first driving device 2 includes a first driving servo motor 13 and a first transmission assembly. The first driving servo motor 13 is fixedly connected to the rear section 7, and the output of the first driving servo motor 13 is driven by the first transmission assembly. The first transmission assembly is fixedly connected to the bistable structure 3, and the first driving servo motor 13 can drive the bistable structure 3 to swing around the first axis through the first transmission assembly. The first drive servo motor 13 is fixedly mounted on the first mounting bracket 16 fixedly disposed in the inner cavity of the fish tail section 7. The first transmission assembly includes a drive arm 14 and a drive support arm 15. The output end of the first drive servo motor 13 is drive-connected to the drive arm 14, which rotates around the second axis. The drive support arm 15 is fixedly connected to a connection position on one side of the drive arm 14, and the connection position is spaced from the first axis in a direction perpendicular to the first axis. The drive support arm 15 includes a clamping arm that extends in a direction perpendicular to the first axis and can clamp and fix the bistable structure 3. The first drive servo motor 13 can drive the drive arm 14 to rotate, and the drive arm 14 drives the fixedly connected drive support arm 15 to rotate. The fixedly connected bistable structure 3 swings around the first axis under the drive of the drive support arm 15. There is a 2mm gap between the limiting groove 19 and the bistable structure 3 so that the bistable structure 3 can drive the fish tail 4 to jump.

[0034] In one embodiment, a cylindrical silicone film sleeve is fabricated and fitted between the middle section 6 and the rear section 7 of the fish body. Silicone adhesive is used to directly fix the silicone film sleeve to the middle section 6 and the rear section 7. On one hand, the silicone film sleeve uses a 0.2mm thick ordinary silicone film, which has sufficient elasticity and a very small elastic modulus, hardly affecting the transition process of the bistable structure. On the other hand, it also allows for the complete coverage of the fish body 1, resulting in a smooth shape and reduced drag.

[0035] In one embodiment, the system further includes a second drive device and two pectoral fins 11. The second drive device is disposed within the middle section 6 of the fish body, and its output component is connected to the two pectoral fins 11. The two pectoral fins 11 partially extend out of the middle section 6 of the fish body. The second drive device can drive the two pectoral fins 11 to rotate around a third axis. The plane of the first axis and the second axis is a first surface, and the third axis is perpendicular to the first surface. The second drive device provides power for the two pectoral fins 11 to rotate around a fourth axis, thereby propelling the fish body 1 to swim in the water. The rotation of the pectoral fins 11 also assists in the movement of the fish body 1 in the water.

[0036] In one embodiment, the second driving device includes a second driving servo motor 8 and a second transmission assembly. The second transmission assembly includes a first gear 9 and a second gear 10. The second driving servo motor 8 is fixedly installed on a second mounting bracket 17 fixedly disposed in the inner cavity of the middle section 6 of the fish body. The output shaft of the second driving servo motor 8 is drivenly connected to the first gear 9. The first gear 9 meshes with the second gear 10. Pectoral fins 11 are fixedly connected to both sides of the second gear 10. The second driving servo motor 8 can drive the pectoral fins 11 to rotate around the fourth axis through the first gear 9 and the second gear 10. The swinging of the pectoral fins 11 can help the entire fish body 1 to swim.

[0037] In one embodiment, a third drive device is further included. The output of the third drive device is fixedly connected to the rear section 7 of the fish. The third drive device is capable of driving the rear section 7 of the fish to rotate around a second axis. The third drive device includes a third drive servo 12, which is fixedly mounted on a mounting platform 18 inside the middle section 6 of the fish. The output of the third drive servo 12 is fixedly connected to the rear section 7 of the fish. The third drive servo 12 is capable of controlling the rear section 7 of the fish to rotate around a third axis.

[0038] The third drive servo motor 12 is installed inside the middle section 6 of the fish body and is installed through the mounting platform set on the middle section 6 of the fish body. The output shaft of the third drive servo motor 12 is fixedly connected to the connecting bracket 20. The end of the connecting bracket 20 that extends out of the middle section 6 of the fish body and is away from the third drive servo motor 12 is fixedly connected to the rear section 7 of the fish body. The third drive servo motor 12 can rotate the rear section 7 of the fish body around the third axis.

[0039] In one embodiment, a control system and a power supply are also included. The control system and power supply are housed within the fish head 5. The control system provides control signals to the first, second, and third driving devices, while the power supply provides a power source for them. Both the control system and power supply are installed within the fish head 5. One end of the fish head 5 is open, while the other ends are closed. The opening is detachably connected to the middle section 6 of the fish body. Both the open end of the fish head 5 and the middle section 6 have concealed through holes. Bolts are used to connect the fish head 5 and the middle section 6 without affecting the smoothness of the fish's shape. A baffle 21 is provided between the fish head 5 and the middle section 6, and the baffle 21 is located in a slot in the middle section 6. The slot, the baffle 21, and the fish head 5 and the middle section 6 are all sealed with silicone. Together with the middle section 6 of the fish body, 21 forms a closed structure inside the fish head 5, preventing water from the middle section 6 of the fish body and external water from entering the fish head 5 and affecting the use of the power supply inside the fish head 5; the power supply can provide power to the first drive device, the second drive device and the third drive device. The baffle is provided with through holes that allow wires to pass through. The fish head 5, the middle section 6 of the fish body and the rear section 7 of the fish body are similar in shape to the fish body, which facilitates swimming. Several hidden through holes are provided on the outside of the fish head 5 and the middle section 6 of the fish body, and the two are connected by bolts to reduce resistance.

[0040] Furthermore, the control system also includes a control chip, which is a Bluetooth chip. The Bluetooth chip receives control signals and generates PWM waves to adjust the servo angles. The first drive servo 13 has a rotation angle of -20° to 20°, the second drive servo 8 has a rotation angle of -90° to 90°, and the third drive servo 12 has a rotation angle of -30° to 30°. The drive arm 14 applies displacement drive to the drive point of the bistable fishtail 4, so as to achieve a large swing amplitude and high speed swing of the bistable fishtail 4 with a small displacement drive. The drive frequency is adjustable from 0 to 5Hz.

[0041] The bistable structure and the fishtail together form a bistable fishtail, such as Figures 12-13 As shown, under the same driving conditions (drive rod swing angle -25°~25°, L=90mm, b=20mm, cross-sectional thickness w=0.8mm, cross-sectional width s=10mm), the average force value (i.e., average thrust value) and the range of force values ​​(i.e., thrust value) of the bistable and non-bistable fishtails in one swing cycle at different driving frequencies are compared. Figure 12 It can be seen that the addition of bistable structure 3 can increase the thrust of the fish tail, and the effect of increasing the average thrust is more significant at high drive frequencies.

[0042] from Figure 13It can be seen that the maximum thrust of the bistable tail in one swing cycle is much greater than that of the non-bistable tail, which indicates that the addition of the bistable structure 3 can significantly increase the instantaneous thrust and improve the maneuverability of the bistable bionic robotic fish.

[0043] from Figure 14 The force (thrust)-time curves of the bistable and non-bistable tails of the biomimetic robotic fish show that, under the thrust generation mode of the bistable tail, the bistable transition can generate a larger instantaneous thrust than the non-bistable tail.

[0044] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A bistable biomimetic robotic fish, characterized in that: The device includes a fish body, a first driving device, a bistable structure, and a fish tail. The first driving device is disposed inside the fish body. The bistable structure has two equilibrium states. The output of the first driving device is connected to one end of the bistable structure. The first driving device can drive the bistable structure to swing around a first axis and change from one equilibrium state to another equilibrium state. The other end of the bistable structure is connected to the fish tail. The swinging of the bistable structure around the first axis can drive the fish tail to swing.

2. The bistable biomimetic robotic fish according to claim 1, characterized in that: The bistable structure is made of an elastic material, and the bistable structure connected to the fish tail has elastic deformation.

3. The bistable biomimetic robotic fish according to claim 1 or 2, characterized in that: The bistable structure includes a first connecting plate, a second connecting plate, and a third connecting plate. The middle part of the first connecting plate is fixedly connected to the output component of the first driving device. One end of the first connecting plate is fixedly connected to one end of the second connecting plate, and the other end of the first connecting plate is fixedly connected to one end of the third connecting plate. The other end of the second connecting plate is a first end with a first connection position. The other end of the third connecting plate is a second end with a second connection position. The first connecting plate, the second connecting plate, and the third connecting plate are all made of elastic material. The first connection position and the second connection position are both connected to the fish tail. The first connecting plate, the second connecting plate, and the third connecting plate connected to the fish tail all have elastic deformation.

4. The bistable biomimetic robotic fish according to claim 3, characterized in that: The distance between the first connection position and the second connection position in the first direction can be adjusted and connected to the fish tail, and the first direction is parallel to the first axis.

5. The bistable biomimetic robotic fish according to claim 3, characterized in that: The bistable structure is made of spring steel or polyester.

6. The bistable biomimetic robotic fish according to claim 3, characterized in that: It also includes a thin film, which is fixedly connected to the bistable structure and can cover the space between the second connecting plate and the third connecting plate.

7. The bistable biomimetic robotic fish according to claim 6, characterized in that: The film is a silicone film, which is wrapped around the second connecting plate and the third connecting plate and covers the space between them.

8. The bistable biomimetic robotic fish according to claim 1, characterized in that: The fish body includes a head, a middle section of the body, and a rear section. The head is fixedly connected to one end of the middle section of the body, and the rear section of the body is rotatably connected to the other end of the middle section of the body around a second axis. The second axis is parallel to the first axis. The first driving device is fixedly installed inside the rear section of the body. A limiting groove is provided at the end of the rear section of the body near the bistable structure. The end of the bistable structure away from the tail is placed in the limiting groove and can swing within the limiting groove.

9. The bistable biomimetic robotic fish according to claim 8, characterized in that: It also includes a second drive device and two pectoral fins. The second drive device is located in the middle section of the fish body. The output of the second drive device is connected to the two pectoral fins. The two pectoral fins extend out of the middle section of the fish body. The second drive device can drive the two pectoral fins to rotate around a third axis. The plane passing through the first axis and the second axis is the first surface. The third axis is perpendicular to the first surface.

10. The bistable biomimetic robotic fish according to claim 8, characterized in that: A third driving device is also provided in the middle section of the fish body. The output component of the third driving device is fixedly connected to the rear section of the fish body. The third driving device can drive the rear section of the fish body to rotate around the second axis.

Images