A composite drive based biomimetic robotic fish

Abstract

The application discloses a bionic robotic fish based on composite driving, comprising: a plurality of driving joints arranged in the fish tail and sequentially hinged along the length direction of the fish tail; a first driving structure arranged in the fish tail and connected with the first driving joint close to the fish head to drive the fish tail to swing by driving the first driving joint to rotate; two flexible cables distributed on both sides of the plurality of driving joints along the direction perpendicular to the length direction of the fish tail and connected with each driving joint; a positioning member located on the side of the first driving joint close to the fish head and connected with the flexible cable; and a second driving structure arranged in the fish tail and connected with the positioning member to drive the fish tail to swing by driving the positioning member to rotate. The application increases rigid driving on the front side of the flexible cable driving through the composite driving mode, effectively improves the overall propulsion performance and hydrodynamic efficiency of the fish tail, and is not only suitable for large-size robotic fish, but also suitable for maneuvering propulsion and attitude control in complex environments.

Description

Technical Field

[0001] This utility model relates to the field of robotic fish technology, and in particular to a biomimetic robotic fish based on composite drive. Background Technology

[0002] Bionic robotic fish have gained widespread attention and application in various fields due to their advantages such as high efficiency, flexibility, and low noise. The performance of their propulsion system directly affects the overall propulsion efficiency, attitude stability, and environmental adaptability of the machine, with the tail structure being particularly critical. In nature, most fish tails exhibit a distribution characteristic of "rigid at the front and flexible at the rear": the front section relies on the coordinated action of muscles and skeleton to generate the main driving torque, while the rear section utilizes compliance and hydrodynamic effects to form a smooth and continuous undulation, thereby achieving both high propulsion efficiency and low flow resistance, and improving attitude adjustment flexibility.

[0003] For example, patent CN10143772A discloses that existing bionic fish often use a single cable-driven method, where a drive structure drives the cable to move, thereby causing the fish's tail to swing. Although the structure is simple, it is only suitable for small-sized fish or relatively simple fluid environments, where a small driving force is sufficient. However, when the size of the fish increases or the fluid environment becomes more complex and variable, the drive system needs to withstand higher traction forces, which can easily lead to uneven cable tension distribution. This can cause control lag and ultimately reduce the propulsion efficiency of the bionic fish.

[0004] Therefore, existing technologies still need to be improved and developed. Utility Model Content

[0005] The technical problem to be solved by this invention is to provide a biomimetic robotic fish based on composite drive, which aims to improve propulsion efficiency, in view of the above-mentioned defects of the prior art.

[0006] The technical solution adopted by this utility model to solve the technical problem is as follows:

[0007] A biomimetic robotic fish based on composite actuation, comprising:

[0008] Multiple drive joints are located inside the fish tail, arranged along the length of the fish tail and hinged sequentially.

[0009] The first drive structure is located inside the fish tail and is connected to the first drive joint near the fish head, so as to drive the fish tail to swing by rotating the first drive joint.

[0010] Two flexible cables are distributed on both sides of multiple drive joints along a direction perpendicular to the length of the fish tail, and are connected to each drive joint.

[0011] A positioning element is located on the side of the first drive joint near the fish head and is connected to the flexible cable;

[0012] The second drive structure is located inside the fish tail and connected to the positioning member, so as to drive the positioning member to rotate and cause the fish tail to swing.

[0013] The biomimetic robotic fish based on composite actuation also includes:

[0014] The elastic element has one end connected to the first drive joint, and the other end passes through each of the intermediate drive joints and is connected to the last drive joint furthest from the fish head; when the fish tail is in a straight state, the elastic element is in a natural state; when the fish tail is in a swinging state, the elastic element is in a deformed state.

[0015] The biomimetic robotic fish based on composite actuation, wherein the first actuation structure includes:

[0016] At least one rigid linkage unit; the rigid linkage unit includes two rigid links distributed vertically; the rigid links extend along the length of the fish tail and are connected to the first drive joint;

[0017] A driver, connected to the rigid link, drives the rigid link to rotate; the plane of rotation of the rigid link is parallel to the extension direction of the rigid link.

[0018] The biomimetic robotic fish based on composite drive, wherein the actuator and the second drive structure are arranged along the length direction of the fish tail, and the second drive structure is located between the actuator and the first drive joint.

[0019] The biomimetic robotic fish based on composite actuation also includes:

[0020] Adapter; the adapter is provided on both sides of the drive joint along the length of the fish tail; the two adapters located between two adjacent drive joints are rotatably connected.

[0021] The biomimetic robotic fish based on composite drive has two adapters located between two adjacent drive joints that are staggered vertically and partially overlap.

[0022] The biomimetic robotic fish based on composite drive, wherein the drive joint is an elliptical drive joint, and the long axis of the drive joint extends vertically and is perpendicular to the length direction of the fish tail.

[0023] The biomimetic robotic fish based on composite drive has multiple drive joints whose long axes decrease sequentially from the head to the tail.

[0024] The biomimetic robotic fish based on composite drive, wherein the positioning component is a circular positioning component, and the central axis of the positioning component extends vertically.

[0025] The biomimetic robotic fish based on composite actuation also includes:

[0026] Fin units, located near the fish's head;

[0027] The third drive structure is located inside the fish head and connected to the fin unit to drive the fin unit to rotate; the rotation plane of the fin unit is perpendicular to the rotation plane of the first drive joint.

[0028] Beneficial effects: In this application, the rigid drive of the first drive structure to the first drive joint and the flexible drive of the second drive structure to each drive joint through the flexible cable realize a composite drive mode, which cleverly integrates the precise control capability of rigid drive with the continuous deformation capability of flexible cable, so that the fish tail can complete large-amplitude swing while having good structural compactness and control stability. Compared with the single cable drive method in the prior art, this application adds a rigid drive to the front of the flexible cable drive, so that the rigid drive and the cable flexible drive cooperate with each other, effectively improving the overall propulsion performance and hydrodynamic efficiency of the fish tail, which is especially suitable for maneuvering propulsion and attitude control in complex environments. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of the biomimetic robotic fish based on composite drive in this utility model;

[0030] Figure 2 This is a first view of the internal structure of the fish tail in this utility model;

[0031] Figure 3 This is a second view of the internal structure of the fish tail in this utility model;

[0032] Figure 4 This is a partially exploded structural diagram of the biomimetic robotic fish based on composite drive in this utility model.

[0033] Figure 5 This is a schematic diagram of the assembly structure of the fin unit at the fish head in this utility model;

[0034] Figure 6 This is a schematic diagram comparing the swinging state of the fish tail and the straight state of the fish tail when the first driving joint and the positioning component rotate in the same direction in this utility model.

[0035] Figure 6 Figure 'a' is a schematic diagram of the fish tail's swinging state when the first driving joint rotates counterclockwise in the same direction as the positioning component;

[0036] Figure 6In the middle, b is a diagram showing the fish tail in a straight position;

[0037] Figure 6 The middle 'c' is a schematic diagram of the fish tail's swinging state when the first driving joint rotates clockwise in the same direction as the positioning component;

[0038] Figure 7 This is a schematic diagram comparing the swinging state of the fish tail and the straight state of the fish tail when the first driving joint and the positioning component rotate in opposite directions in this utility model.

[0039] Figure 7 The diagram in 'd' shows the swaying state of the fish tail when the first driving joint rotates clockwise and the positioning component rotates counterclockwise.

[0040] Figure 7 The middle 'e' is a diagram showing the fish tail in a straight position;

[0041] Figure 7 The diagram in f is a schematic of the fish tail swinging state when the first driving joint rotates counterclockwise and the positioning component rotates clockwise. Detailed Implementation

[0042] The embodiments of this utility model will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be understood that the preferred embodiments are only for illustrating this utility model and not for limiting the scope of protection of this utility model.

[0043] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0044] The inventors of this application discovered through research that, in nature, the tail structure of most fish exhibits a typical distribution characteristic of "rigid at the front and flexible at the rear." The front section of the tail relies on the strong synergy of muscles and skeleton to generate the main driving torque; while the middle and rear sections rely on high flexibility to adapt to hydrodynamics, forming a smooth and continuous undulating shape. This structural design not only helps to improve propulsion efficiency but also effectively reduces fluid resistance and enhances the flexibility of attitude adjustment, representing an efficient locomotion mechanism developed through long-term evolution in fish.

[0045] Existing technologies often employ a single cable-driven method to achieve fish tail swaying. This involves placing a cable within the fish tail and connecting it to a drive structure. The drive structure moves the cable, which in turn propels the tail to sway. While cable movement provides a degree of flexibility, creating a continuous wave pattern, it is only suitable for smaller fish and simple fluid environments (where there are few obstacles and the fish can pass through smoothly without needing to sway at large or multiple angles). For larger fish and more complex fluid environments, this simple cable-driven method requires the drive system to withstand higher traction forces, leading to uneven cable tension distribution. This can cause control lag, limited wave amplitude, and ultimately, reduced propulsion efficiency for the biomimetic fish.

[0046] To address the aforementioned technical problems, this application provides a biomimetic robotic fish based on composite actuation, such as... Figure 2 and Figure 3 As shown, the biomimetic robotic fish based on composite drive includes: multiple drive joints 1, a first drive structure 2, two flexible cables 3, a positioning element 4, and a second drive structure 5; the multiple drive joints 1 are disposed within the tail 100, arranged along the length direction of the tail 100, and hinged sequentially; the first drive structure 2 is disposed within the tail 100 and connected to the first drive joint A near the head 200, so as to drive the tail 100 to swing by rotating the first drive joint A; the two flexible cables 3 are distributed on both sides of the multiple drive joints 1 along a direction perpendicular to the length direction of the tail 100, and are connected to each drive joint 1; the positioning element 4 is located on the side of the first drive joint A near the head 200 and is connected to the flexible cable 3; the second drive structure 5 is disposed within the tail 100 and connected to the positioning element 4, so as to drive the tail 100 to swing by rotating the positioning element 4.

[0047] Taking a fish head 200 facing forward and a fish tail 100 facing backward as an example: Specifically, multiple drive joints 1 are all located inside the fish tail 100, and are arranged at intervals along the length of the fish tail 100 and hinged sequentially; the drive joint 1 closest to the direction of the fish head 200 is the first drive joint A, and the first drive joint A is hinged to the drive joint 1 located in the direction of the fish tail 100 (the second drive joint behind the first drive joint A); similarly, the second drive joint is hinged to the third drive joint behind it, and so on.

[0048] The first drive structure 2 is located on the front side of the first drive joint A (the first drive joint A is located on the side closer to the fish head 200, where the front, back, left, right, up, and down directions are as follows). Figure 1As shown), it is connected to the first drive joint A, thereby driving the first drive joint A to rotate along the horizontal plane and causing the fishtail 100 to swing; therefore, the connection between the first drive structure 2 and the first drive joint A is used to output a large torque to provide a main propulsion force with rigidity and fast response characteristics, which is suitable for high-frequency command adjustment and fast steering. Two flexible cables 3 are arranged on both sides of the fishtail 100 in the left and right horizontal direction, and each flexible cable 3 is connected to all drive joints 1 and also to the positioning member 4 on the second drive structure 5; when the second drive structure 5 drives the positioning member 4 to rotate along the horizontal plane, the rotation of the positioning member 4 is converted into the opposite movement of the two flexible cables 3 (one flexible cable 3 moves forward and the other flexible cable 3 moves backward), which drives the fishtail 100 to swing, realizing the linkage control of the middle and rear section of the fishtail 100.

[0049] The first drive structure 2 is connected to the first drive joint A to provide rigid drive for the front section of the fish tail 100, which can simulate the force exerted by the natural fish tail 100 and ensure overall output efficiency. The second drive structure 5 is connected to the positioning component 4, the flexible cable 3 and each drive joint 1 to provide flexible drive for the middle and rear sections of the fish tail 100. With the help of its flexible characteristics, it forms continuous undulation in space, thereby realizing streamlined tail movement, which is close to the undulating behavior of the fish tail 100 of real fish. This makes the bionic robotic fish based on composite drive have a more natural and coherent swaying trajectory in the water.

[0050] As can be seen, in this application, the rigid drive of the first drive structure 2 to the first drive joint A and the flexible drive of the second drive structure 5 to each drive joint 1 through the flexible cable 3 achieve a composite drive mode, which cleverly integrates the precise control capability of rigid drive with the continuous deformation capability of flexible cable 3, so that the fish tail 100 can complete large-amplitude swing while having good structural compactness and control stability. Compared with the single cable drive method in the prior art, this application adds a rigid drive to the front of the flexible cable 3 drive, so that the rigid drive and the cable flexible drive cooperate with each other, effectively improving the overall propulsion performance and hydrodynamic efficiency of the fish tail 100. It can not only be applied to large-size robotic fish, but also adapt to the maneuver propulsion and attitude control in complex environments.

[0051] It should be noted that the rotation of the first drive joint A is a rotation about the first drive structure 2; the plane of rotation of the first drive joint A under the drive of the first drive structure 2 is parallel to the plane of rotation of the positioning member 4 under the drive of the second drive structure 5, and both are swinging in the horizontal direction. Therefore, when both the first drive structure 2 and the second drive structure 5 are activated, the swing of the fish tail 100 driven by the rotation of the first drive joint A and the swing of the fish tail 100 driven by the two flexible cables 3 can be connected to each other, realizing the swing of the fish tail 100 in more than one different posture, which is more suitable for maneuvering propulsion and attitude control in complex environments.

[0052] For example: Figure 6 As shown, when both the first drive structure 2 and the second drive structure 5 are activated, and the first drive structure 2 drives the first drive joint A to rotate counterclockwise around the first drive structure 2, and the second drive structure 5 drives the positioning component 4 to rotate counterclockwise (the first drive joint A and the positioning component 4 rotate counterclockwise in the same direction, as shown in the diagram), the first drive joint A and the positioning component 4 rotate counterclockwise in the same direction. Figure 6 When (as shown in a), the front part of the fish tail 100 swings to the left; one end of the flexible cable 3 on the left side connected to the positioning part 4 is pulled towards the fish head 200, and the rear part of the fish tail 100 swings to the left. Thus, the entire fish tail 100 swings to the left relative to the fish head 200, presenting a continuous arc.

[0053] like Figure 6 As shown, when both the first drive structure 2 and the second drive structure 5 are activated, and the first drive structure 2 drives the first drive joint A to rotate clockwise around the first drive structure 2, and the second drive structure 5 drives the positioning member 4 to rotate clockwise (the first drive joint A and the positioning member 4 rotate clockwise in the same direction, as shown in the diagram), Figure 6 When (as shown in c), the front part of the fish tail 100 swings to the right; one end of the right flexible cable 3 connected to the positioning part 4 is pulled towards the fish head 200, and the rear end of the fish tail 100 swings to the right. Then the entire fish tail 100 swings to the right relative to the fish head 200, presenting a continuous arc.

[0054] like Figure 7 As shown, when both the first drive structure 2 and the second drive structure 5 are activated, and the first drive structure 2 drives the first drive joint A to rotate clockwise around the first drive structure 2, while the second drive structure 5 drives the positioning member 4 to rotate counterclockwise (the first drive joint A and the positioning member 4 rotate in opposite directions, as shown in the diagram), Figure 7 When (as shown in d), the front part of the fish tail 100 swings to the right; one end of the left flexible cable 3 connected to the positioning part 4 is pulled towards the fish head 200, and the rear part of the fish tail 100 swings to the left, so the fish tail 100 as a whole presents a continuous S shape.

[0055] like Figure 7 As shown, when both the first drive structure 2 and the second drive structure 5 are activated, and the first drive structure 2 drives the first drive joint A to rotate counterclockwise around the first drive structure 2, while the second drive structure 5 drives the positioning member 4 to rotate clockwise (the first drive joint A and the positioning member 4 rotate in opposite directions, as shown in the diagram), the first drive structure 2 drives the first drive joint A to rotate counterclockwise around the first drive structure 2, while the second drive structure 5 drives the positioning member 4 to rotate clockwise. Figure 7 When (as shown in f), the front part of the fish tail 100 swings to the left; one end of the right flexible cable 3 connected to the positioning part 4 is pulled towards the fish head 200, and the rear part of the fish tail 100 swings to the right, so the fish tail 100 as a whole presents a continuous S shape.

[0056] Therefore, by rationally configuring the driving methods of the first driving structure 2 and the second driving structure 5, the power performance and bionic performance of the fish tail 100 can be effectively improved, achieving high amplitude and high frequency tail swinging motion, enhancing propulsion efficiency and attitude control capability, and making it suitable for bionic robotic fish of different sizes, meeting their needs for efficient maneuvering propulsion and stable attitude adjustment in complex aquatic environments.

[0057] One embodiment of this application, such as Figure 2 , Figure 3 and Figure 4 As shown, the biomimetic robotic fish based on composite drive also includes an elastic element 6; one end of the elastic element 6 is connected to the first drive joint A, and the other end of the elastic element 6 passes through each of the intermediate drive joints 1 and is connected to the last drive joint 1 furthest from the fish head 200; when the fish tail 100 is in a straight state (such as...), Figure 1 , Figure 6 b and Figure 7 When (as shown in e), the elastic element 6 is in its natural state; when the fish tail 100 is in a swinging state, the elastic element 6 is in a deformed state.

[0058] Specifically, the elastic element 6 extends along the length of the fish tail 100, and its two ends are connected to the first drive joint A and the last drive joint 1 away from the fish head 200, respectively. When the fish tail 100 is in a straight state, the elastic element 6 is in a natural state and does not undergo elastic deformation; when the first drive joint A rotates under the drive of the first drive structure 2 and / or multiple drive joints 1 rotate under the drive of the flexible cable 3, the front end of the elastic element 6 bends relative to the rear end, and the bending direction matches the rotation direction and rotation angle of the corresponding drive joints 1, so that the elastic element 6 changes to a deformed state.

[0059] In this embodiment, the connection point of the corresponding elastic element 6 on the drive joint 1 is located at the center of the drive joint 1, so that the elastic element 6, as an elastic return element, can actively release elastic restoring force when the flexible cable 3 is relaxed, automatically driving the fish tail 100 to return to the neutral position, ensuring the natural rebound and stability of the fish tail 100 structure during the movement, avoiding the movement deviation caused by inertia or water flow disturbance, and ensuring the continuity of the continuous swing of the fish tail 100 and the dynamic stability of the system.

[0060] One implementation method in this embodiment, such as Figure 3 and Figure 4 As shown, a fixed base 7 is provided on the first drive joint A, and brass guide blocks 8 are provided on the remaining drive joints 1. One end of the elastic element 6 is connected to the fixed base 7 by screw positioning. The elastic element 6 is also connected to the brass blade block by screw to realize the positioning of the elastic element 6 in the length direction.

[0061] In one embodiment of this invention, the elastic element 6 is a flat rectangular elastic element 6, and the length direction of the elastic element 6 is the same as the length direction of the fish tail 100, and the width direction of the elastic element 6 is the up and down direction; in this way, the elastic deformation direction of the elastic element 6 can better conform to the left and right swinging direction of the fish tail 100.

[0062] One embodiment of this application, such as Figure 2 and Figure 3 As shown, the first drive structure 2 includes a driver 21 and at least one rigid link unit; the rigid link unit includes two rigid links 22 distributed vertically; the rigid links 22 extend along the length direction of the fish tail 100 and are respectively connected to the driver 21 and the first drive joint A; the driver 21 is connected to the rigid links 22 to drive the rigid links 22 to rotate; the plane of rotation of the rigid links 22 is parallel to the extension direction of the rigid links 22.

[0063] Specifically, the rigid linkage unit includes two rigid linkages 22, which are distributed vertically. The rigid linkages 22 extend along the length of the fish tail 100, and their two ends are connected to the actuator 21 and the first drive joint A, respectively. When the actuator 21 is activated, the rigid linkage 22 rotates around the connection point between itself and the actuator 21 along the horizontal plane, thereby driving the first drive joint A to rotate around the actuator 21, thus realizing the swinging of the fish tail 100.

[0064] Considering the internal space of the biomimetic robotic fish and the overall size of the first drive joint A, in one embodiment of this invention, the rigid linkage unit is one.

[0065] In one embodiment of this invention, the driver 21 includes two servo motors, with one drive shaft facing upwards and the other downwards, thereby achieving rotational drive of the two rigid connecting rods 22. This composite drive mode combines the rapid response capability of motor drive with the smoothness of flexible cable 3 transmission, improving the output torque and fluctuation amplitude of the fish tail 100 without significantly increasing the fish body volume, and enhancing the smoothness and motion continuity of the fish tail 100.

[0066] In one embodiment of this invention, the actuator 21 and the second drive structure 5 are arranged along the length of the fish tail 100, with the second drive structure 5 located on the side of the actuator 21 closest to the fish tail 100. Specifically, the second drive structure 5 is located between the actuator 21 and the first drive joint A, and is mounted on the lower rigid link 22 in the rigid link unit. When the first drive structure 2 is activated, it not only drives the rigid link 22 to rotate, but also drives the second drive structure 5 to rotate. This ensures that when both the second drive structure 5 and the first drive structure 2 are activated, regardless of whether the rotation direction of the first drive joint A and the positioning member 4 is the same or opposite, the swinging of the front and rear sections of the fish tail 100 can form smooth and continuous lines, thereby ensuring the continuity of the continuous swinging of the fish tail 100 and the dynamic stability of the system.

[0067] Understandably, the positioning element 4 is also located between the driver 21 and the first drive joint A, and is connected to the second drive structure 5 and the two flexible cables 3 respectively.

[0068] One embodiment of this application, such as Figure 2 and Figure 3 As shown, the bionic robotic fish based on composite drive also includes adapter 9; adapter 9 is provided on both sides of the drive joint 1 along the length direction of the fish tail 100, and the two adapter 9 located between two adjacent drive joints 1 are rotatably connected.

[0069] Specifically, each drive joint 1 has a connecting member 9 on both its front and rear sides, so the hinge between two adjacent drive joints 1 is the hinge between two adjacent connecting members 9. Since each drive joint 1 is connected to the flexible cable 3, when the flexible cable 3 moves, each drive joint 1 can move relative to the two adjacent drive joints 1 at the front and rear under the action of the hinge between the two adjacent connecting members 9, thus realizing the swinging of the fish tail 100.

[0070] It is understandable that the first drive joint A is only provided with the adapter 9 on the rear side, and is not provided with the adapter 9 on the front side, so as to give way to the rigid link 22, ensuring that the front side of the first drive joint A can be connected to the driver 21 through the rigid link 22, and the rear side of the first drive joint A can be hinged to the adjacent drive joint 1 through the adapter 9.

[0071] In one embodiment of this invention, two adapters 9 located between two adjacent drive joints 1 are arranged vertically in a staggered manner and partially overlap.

[0072] Specifically, two adjacent adapters 9 are staggered vertically, partially overlapping, and hinged by a pin 10. The central axis of the pin 10 extends vertically, passes through the two adapters 9 in sequence, and can rotate relative to the two adapters 9; thus, when the first drive structure 2 and / or the second drive structure 5 are activated, a relative staggered rotation can be generated between the two adjacent drive joints 1, realizing the swinging of the fishtail 100.

[0073] In this embodiment, the two adjacent adapters 9 are staggered vertically and partially overlap, making the connection between the two adjacent adapters 9 smoother and more stable. This reduces the horizontal offset between the two adjacent adapters 9 when the drive joint 1 moves, thus making the lines generated by the swing of the fish tail 100 smoother. The overall structure is compact, the control is natural, and the biomimicry is strong.

[0074] In one embodiment of this application, the drive joint 1 is an elliptical drive joint, and the long axis of the drive joint 1 extends vertically and is perpendicular to the length direction of the fish tail 100.

[0075] Specifically, the long axis of the drive joint 1 extends vertically, and the short axis of the drive joint 1 is arranged horizontally left and right. The long axis of the drive joint 1 is perpendicular to the length direction of the fish tail 100, which makes the appearance of the drive joint 1 more closely fit and adapt to the shape of the fish tail 100. When the drive joint 1 moves, it can better reflect the smoothness of the fish tail 100 swinging. Moreover, the fish tail 100 is not prone to vertical deformation during swinging, and the swinging in the left and right directions is more flexible, which is conducive to achieving flexible left and right swinging and stronger biomimicry.

[0076] In one embodiment of this application, the long axes of the multiple drive joints 1 decrease sequentially from the fish head 200 to the fish tail 100. Specifically, the closer to the end of the fish tail 100, the smaller the long axis of the drive joint 1; the closer to the fish head 200, the larger the long axis of the drive joint 1, so that the multiple drive joints 1 form a flexible gradient, the fish tail 100 has sufficient support and power transmission capacity, making it easier to achieve large-amplitude swinging and more closely resembling the movement pattern of a real fish tail 100.

[0077] In one embodiment of this application, the positioning member 4 is a circular positioning member 4, and the central axis of the positioning member 4 extends vertically. After the flexible cable 3 is connected to the positioning member 4, no matter which direction the positioning member 4 rotates, the part of the flexible cable 3 near the positioning member 4 can fit against the outer circumferential surface of the positioning member 4 and thus be supported by the positioning member 4. In this way, even if the rotation direction of the first driving joint A is opposite to the rotation direction of the positioning member 4 under the drive of the first driving structure 2 and the second driving structure 5, a smooth transition can be formed at the connection between the front section and the middle and rear sections of the fish tail 100, and the overall structure is compact and the control is natural.

[0078] like Figure 1 and Figure 5 As shown, the bionic robotic fish based on composite drive also includes a fin unit 11 and a third drive structure 12; the fin unit 11 is close to the fish head 200; the third drive structure 12 is disposed inside the fish head 200 and connected to the fin unit 11 to drive the fin unit 11 to rotate; the rotation plane of the fin unit 11 is perpendicular to the rotation plane of the first drive joint A.

[0079] Specifically, the fin unit 11 includes two fins 111 distributed left and right, with the rotation plane of the fins 111 being a vertical plane. The third drive structure 12 includes a drive member 121, a first transmission gear 122, a second transmission gear 123, and a transmission rod 124. The drive member 121 includes a motor, and its drive shaft is coaxially connected to the first transmission gear 122, driving the first transmission gear 122 to rotate along the vertical plane. The second transmission gear 123 is coaxially connected to the transmission rod 124 and meshes with the first transmission gear 122, thereby driving the transmission rod 124 to rotate through the second transmission gear 123. The two ends of the transmission rod 124 are respectively connected to the two fins 111, so that when the transmission rod 124 rotates, it can synchronously drive the two fins 111 to rotate.

[0080] In summary, this utility model provides a biomimetic robotic fish based on composite drive, comprising: multiple drive joints disposed within the tail, arranged along the length of the tail and hinged sequentially; a first drive structure disposed within the tail and connected to the first drive joint near the head, so as to drive the tail to swing by rotating the first drive joint; two flexible cables distributed on both sides of the multiple drive joints along a direction perpendicular to the length of the tail and connected to each drive joint; a positioning member located on the side of the first drive joint near the head and connected to the flexible cables; and a second drive structure disposed within the tail and connected to the positioning member, so as to drive the tail to swing by rotating the positioning member. In this application, the rigid drive of the first drive structure to the first drive joint and the flexible drive of the second drive structure to each drive joint via flexible cables achieve a composite drive mode. This cleverly integrates the precise control capability of rigid drive with the continuous deformation capability of flexible cables, enabling the fish tail to achieve large-amplitude swings while maintaining good structural compactness and control stability. Compared to the single cable drive method in the prior art, this application adds a rigid drive to the front of the flexible cable drive, allowing the rigid drive and the flexible cable drive to work together to effectively improve the overall propulsion performance and hydrodynamic efficiency of the fish tail. This not only makes it suitable for large-sized robotic fish but also adapts to maneuver propulsion and attitude control in complex environments.

[0081] It should be understood that the application of this utility model is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A biomimetic robotic fish based on composite actuation, characterized in that, It includes: Multiple drive joints are located inside the fish tail, arranged along the length of the fish tail and hinged sequentially. The first drive structure is located inside the fish tail and is connected to the first drive joint near the fish head, so as to drive the fish tail to swing by rotating the first drive joint. Two flexible cables are distributed on both sides of multiple drive joints along a direction perpendicular to the length of the fish tail, and are connected to each drive joint. A positioning element is located on the side of the first drive joint near the fish head and is connected to the flexible cable; The second drive structure is located inside the fish tail and connected to the positioning member, so as to drive the positioning member to rotate and cause the fish tail to swing.

2. The biomimetic robotic fish based on composite actuation according to claim 1, characterized in that, It also includes: The elastic element has one end connected to the first drive joint, and the other end passes through each of the intermediate drive joints and is connected to the last drive joint furthest from the fish head. When the fish tail is in a straight state, the elastic element is in a natural state; when the fish tail is in a swinging state, the elastic element is in a deformed state.

3. The biomimetic robotic fish based on composite actuation according to claim 1, characterized in that, The first driving structure includes: At least one rigid linkage unit; the rigid linkage unit includes two rigid links distributed vertically; the rigid links extend along the length of the fish tail and are connected to the first drive joint; A driver, connected to the rigid link, drives the rigid link to rotate; the plane of rotation of the rigid link is parallel to the extension direction of the rigid link.

4. The biomimetic robotic fish based on composite actuation according to claim 3, characterized in that, The driver and the second drive structure are arranged along the length of the fish tail, and the second drive structure is located between the driver and the first drive joint.

5. The biomimetic robotic fish based on composite actuation according to claim 1, characterized in that, It also includes: Adapter; the adapter is provided on both sides of the drive joint along the length of the fish tail; the two adapters located between two adjacent drive joints are rotatably connected.

6. The biomimetic robotic fish based on composite actuation according to claim 5, characterized in that, The two adapters located between two adjacent drive joints are staggered vertically and partially overlap.

7. The biomimetic robotic fish based on composite actuation according to claim 1, characterized in that, The drive joint is an elliptical drive joint, and the long axis of the drive joint extends vertically and is perpendicular to the length direction of the fish tail.

8. The biomimetic robotic fish based on composite actuation according to claim 7, characterized in that, The major axes of the multiple drive joints decrease sequentially from the head to the tail of the fish.

9. The biomimetic robotic fish based on composite actuation according to claim 1, characterized in that, The positioning element is a circular positioning element, and the central axis of the positioning element extends vertically.

10. The biomimetic robotic fish based on composite actuation according to claim 1, characterized in that, It also includes: Fin units, located near the fish's head; The third drive structure is located inside the fish head and connected to the fin unit to drive the fin unit to rotate; the rotation plane of the fin unit is perpendicular to the rotation plane of the first drive joint.

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