Earthworm-like variable-rigidity bionic robotic fish

Abstract

The invention discloses an earthworm-like variable-rigidity bionic robotic fish. The earthworm-like variable-rigidity bionic robotic fish comprises a head, the pneumatic device is arranged in the head part; one axial end of the paper folding structure is connected with the head part; the pneumatic device is connected with the paper folding structure and used for inflating the paper folding structure or exhausting air from the paper folding structure so as to drive the paper folding structure to stretch out and draw back in the axial direction. The driving device is arranged in the head part; and the wire drawing structure is connected with the driving device and the paper folding structure so as to drive the paper folding structure to bend under the driving of the driving device. A paper folding structure and a wire pulling structure are combined, the rigidity of a fish body is adjusted through air suction and inflation of the paper folding structure by a pneumatic device, the pressure intensity in the paper folding mechanism is adjusted, earthworm-like wriggling and swimming are generated, and the trafficability in operation in a narrow space is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of robotic fish, and in particular to an earthworm-like bionic robotic fish with variable stiffness. Background Art

[0002] Bionic robot fish are mainly divided into two types according to their propulsion methods: robot fish with body tail fin propulsion mode and robot fish with middle fin to fin propulsion mode. Compared with the latter, the former has the characteristics of high propulsion efficiency, fast startup speed and long-term high-speed operation underwater, which has attracted many inventors and researchers to engage in the research and development of this type of robot fish. However, the current research on the influence of body stiffness on swimming performance is still immature, and the morphological adjustment control of existing variable stiffness bionic robot fish is very limited, and most of them cannot effectively stretch or change shape.

[0003] For example, patent number CN117985211A discloses controlling the heating temperature of the heating element by a temperature control unit to adjust the stiffness of the tail fin skeleton. However, the flexibility is low when performing large tail swings, and the earthworm-like peristaltic swimming cannot be completed, resulting in low passability when operating in narrow spaces.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] The technical problem to be solved by the present invention is that, in view of the above-mentioned defects of the prior art, a variable stiffness bionic robot fish similar to an earthworm is provided, which aims to realize earthworm-like peristaltic swimming and improve the passability of operations in narrow spaces.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0007] A bionic earthworm-like robot fish with variable stiffness, comprising a head, and further comprising:

[0008] A pneumatic device disposed in the head;

[0009] An origami structure, one axial end of which is connected to the head; the pneumatic device is connected to the origami structure and is used to inflate or evacuate air from the origami structure to drive the origami structure to expand and contract along the axial direction;

[0010] The driving device is arranged in the head.

[0011] The earthworm-like variable stiffness bionic robotic fish, wherein the pneumatic device comprises:

[0012] Gas cylinders;

[0013] A reversing valve connected to the origami structure;

[0014] The air pump is arranged between the gas storage bottle and the reversing valve, and is connected to the gas storage bottle and the reversing valve respectively.

[0015] The earthworm-like variable stiffness bionic robotic fish further comprises:

[0016] The pulling wire structure is connected to the driving device and the origami structure respectively, so as to drive the origami structure to bend under the driving of the driving device.

[0017] The earthworm-like variable stiffness bionic robotic fish, wherein the pull-wire structure comprises:

[0018] A first pull wire, located on one side of the origami structure in a radial direction, with one end of the first pull wire connected to the driving device and the other end connected to the origami structure;

[0019] The second pull wire is symmetrically arranged on the other radial side of the origami structure, and one end of the second pull wire is connected to the driving device, and the other end is connected to the origami structure.

[0020] The earthworm-like variable stiffness bionic robotic fish, wherein the driving device comprises:

[0021] Steering gear;

[0022] A steering wheel, arranged on the steering gear, to rotate along a horizontal plane under the drive of the steering gear;

[0023] The first pull wire and the second pull wire are distributed on both sides of the steering disc and are both connected to the steering disc.

[0024] The earthworm-like variable stiffness bionic robotic fish, wherein the pull-wire structure further comprises:

[0025] The first fixing plate is arranged on the origami structure and can reciprocate along the axial direction with the origami structure; the first pull wire and the second pull wire are located on both sides of the first fixing plate and are both connected to the first fixing plate.

[0026] The earthworm-like variable stiffness bionic robotic fish, wherein the pull-wire structure further comprises:

[0027] A second fixing plate, disposed on the origami structure and located between the head and the first fixing plate;

[0028] The second wire fixing plate is provided with a first assembly hole and a second assembly hole, the first pull wire passes through the first assembly hole and is loosely matched with the first assembly hole; the second pull wire passes through the second assembly hole and is loosely matched with the second assembly hole.

[0029] The earthworm-like variable stiffness bionic robotic fish further comprises:

[0030] A tail fin, arranged at an end of the origami structure away from the head;

[0031] Two push plate structures are symmetrically arranged on both sides of the tail fin.

[0032] The earthworm-like variable stiffness bionic robotic fish, wherein the push plate structure comprises:

[0033] A flexible connector connected to the tail fin;

[0034] A first push plate, disposed on the flexible connecting member;

[0035] The second push plate is arranged on the flexible connecting member and is located on a side of the first push plate away from the origami structure.

[0036] The earthworm-like variable stiffness bionic robotic fish, wherein the push plate structure further comprises:

[0037] The elastic pad is arranged on the flexible connecting member and is located between the first pushing plate and the second pushing plate.

[0038] Beneficial effect: In the present application, the origami structure is combined with the wire pulling structure. The pneumatic device is used to inflate and evacuate the origami structure, thereby adjusting the internal pressure of the origami structure to achieve spatial folding and stretching deformation of the origami structure, thereby adjusting the stiffness of the fish body and generating earthworm-like peristaltic swimming, which significantly improves the passability in narrow space operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the overall structure of the earthworm-like variable stiffness bionic robotic fish described in the present invention;

[0040] Figure 2 This is a schematic diagram of the internal structure of the earthworm-like variable stiffness bionic robotic fish described in the present invention;

[0041] Figure 3 It is a schematic diagram of a partial decomposition structure of the earthworm-like variable stiffness bionic robotic fish of the present invention;

[0042] Figure 4 is a schematic diagram of the assembly structure of the driving device, the first pull wire and the second pull wire in the present invention;

[0043] Figure 5 This is a comparison diagram of different turning states of the earthworm-like variable stiffness bionic robotic fish described in the present invention;

[0044] Figure 5 Figure a is a schematic diagram of the turning of the earthworm-like variable stiffness bionic robotic fish when the second pull line is tightened in the present invention;

[0045] Figure 5 b is a schematic diagram of the earthworm-like variable stiffness bionic robotic fish of the present invention when moving straight;

[0046] Figure 5 Figure c is a schematic diagram of the turning of the earthworm-like variable stiffness bionic robotic fish when the first pull line is tightened in the present invention;

[0047] Figure 6 is a state comparison diagram of the earthworm-like variable stiffness bionic robotic fish when the origami structure of the present invention is extended toward the tail;

[0048] Figure 6 d in the figure is a reference diagram of the use state of the earthworm-like variable stiffness bionic robotic fish in a natural state;

[0049] Figure 6 Figure e is a reference diagram of the use state of the earthworm-like variable stiffness bionic robotic fish when the origami structure of the present invention is initially stretched;

[0050] Figure 6 Fig. f is a reference diagram of the use state of the earthworm-like variable stiffness bionic robotic fish when the origami structure of the present invention continues to stretch;

[0051] Figure 7 is a state comparison diagram of the earthworm-like variable stiffness bionic robotic fish when the origami structure of the present invention retracts toward the head;

[0052] Figure 7 g is a reference diagram of the use state of the earthworm-like variable stiffness bionic robotic fish when the origami structure of the present invention is stretched;

[0053] Figure 7 h is a reference diagram of the use state of the earthworm-like variable stiffness bionic robotic fish when the origami structure of the present invention is initially retracted;

[0054] Figure 7 Reference k in the figure is a reference diagram of the use state of the earthworm-like variable stiffness bionic robotic fish when the origami structure in the present invention continues to retract to a natural state. DETAILED DESCRIPTION

[0055] The following will describe the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention.

[0056] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0057] The present application provides a bionic robot fish with variable stiffness similar to an earthworm, such as Figure 1 and Figure 2 As shown, the earthworm-like variable stiffness bionic robot fish includes: a head 1, a pneumatic device 2, an origami structure 3 and a driving device 4; the pneumatic device 2 is arranged in the head 1; one axial end of the origami structure 3 is connected to the head 1; the pneumatic device 2 is connected to the origami structure 3, and is used to inflate the origami structure 3 or extract air from the origami structure 3 to drive the origami structure 3 to extend and retract axially; the driving device 4 is arranged in the head 1.

[0058] Specifically, the origami structure 3 is tubular, that is, the origami structure 3 has a cavity inside to carry gas. The origami structure 3 is composed of a plurality of origami units, which are arranged in a straight line along the axial direction, and the radial side of each origami unit is rhombus-shaped and folded inward at the center to form an angle β. The pneumatic device 2 is connected to the origami structure 3, so as to inflate and evacuate the inner cavity of the origami structure 3 to change the pressure of the inner cavity of the origami structure 3, thereby changing the shape of the origami structure 3.

[0059] When the origami structure 3 is inflated, the angle β (e.g. Figure 7 The origami structure 3 extends axially, and the axial length of the origami structure 3 increases (as shown in FIG. Figure 6 As shown), the rigidity of the fish body is improved to meet the needs of rapid swimming; when air is pumped out of the origami structure 3, the angle β decreases, and the origami structure 3 retracts axially (as shown Figure 7 As shown in the figure, the axial length of the origami structure 3 is reduced, which reduces the rigidity of the fish body and softens the fish body, making it easier to change the swimming direction and complete the turn. The design of the origami mechanism allows it to change during the process of gas injection or discharge. This "spatial foldability" enables the robot fish to control its shape by adjusting the amount of gas. Through the different folding modes of the origami structure 3, the robot fish can achieve volume expansion or contraction, and then adjust the rigidity and flexibility of swimming. In relatively narrow waters, the spatial foldability of the origami structure 3 is utilized, and the origami structure 3 is pumped and inflated in cooperation with the pneumatic device 2, so that the fish body can perform telescopic movements, which can achieve variable rigidity and variable volume swimming, thereby effectively improving the flexibility and adaptability of the bionic robot fish.

[0060] Earthworm-like peristalsis is a bionic motion mode that imitates the wave-like muscle contraction and expansion movement of earthworms or similar organisms when they move. When earthworms crawl in the soil, they use a series of continuous wave-like muscle contractions and relaxations to move their bodies forward and backward segment by segment, forming a wave-like peristaltic motion. The drive device 4 described in this application is combined with the pull-wire structure 5 to imitate the muscle closure of fish. The pull-wire structure 5 is driven by the drive device 4 to move, pulling the fish body cavity formed by the origami structure 3, so that the bionic robot fish can perform a large-scale tail-swinging motion, thereby generating thrust. In narrow space operations, the coordinated movement of the origami mechanism and the pull-wire mechanism produces earthworm-like peristaltic swimming, which significantly improves the passability in narrow space operations.

[0061] Therefore, in the present application, the pneumatic device 2 inflates and deflates the origami structure 3 to adjust the pressure inside the origami mechanism, thereby achieving spatial folding and stretching deformation of the origami structure 3, thereby adjusting the stiffness of the fish body, so that the robot fish can adapt to different task requirements and environmental changes, produce earthworm-like peristaltic swimming, and significantly improve its passability in narrow space operations.

[0062] In one embodiment of the present application, Figure 2 and Figure 3 As shown, the pneumatic device 2 includes a gas cylinder 21, a reversing valve 22 and an air pump 23; the reversing valve 22 is connected to the origami structure 3; the air pump 23 is arranged between the gas cylinder 21 and the reversing valve 22, and is respectively connected to the gas cylinder 21 and the reversing valve 22.

[0063] Specifically, the gas cylinder 21, the air pump 23, the reversing valve 22 and the origami structure 3 are connected in sequence; the gas cylinder 21 is used to store compressed gas, the gas cylinder 21 is connected to one end of the air pump 23 through a pipeline, and the other end of the air pump 23 is connected to the reversing valve 22, and the gas is transported from the gas cylinder 21 to the reversing valve 22 through the air pump 23.

[0064] The reversing valve 22 is a three-position four-way reversing valve, and is used to control the flow direction and flow rate of the gas. The flow direction of the gas is controlled by changing the position of the valve body, so as to realize the delivery of gas into the origami structure 3 and the extraction of gas from the origami structure 3. When the reversing valve 22 is in the inflated state, the gas flows into the inner cavity (air chamber) of the origami structure 3 through the reversing valve, pushing the origami structure 3 to stretch and expand, making the origami structure 3 harden, and increasing its volume and shape. When it is necessary to soften or reduce the volume of the origami structure 3, the reversing valve 22 is switched to the exhaust state, and the gas is discharged from the inner cavity of the origami structure 3, and the origami structure 3 is reduced in volume, softened, and its rigidity is reduced.

[0065] In one embodiment of the present application, the earthworm-like variable stiffness bionic robotic fish further includes a pull-wire structure 5 (such as Figure 3 The pull-wire structure 5 is connected to the driving device 4 and the origami structure 3, respectively, so as to drive the origami structure 3 to bend under the drive of the driving device 4. The driving device 4 in the present application is combined with the pull-wire structure 5 to imitate the muscle closure of fish. The pull-wire structure 5 is driven by the driving device 4 to move, and the fish body cavity formed by the origami structure 3 is pulled, so that the bionic robotic fish can perform a large-scale tail swinging movement, thereby generating thrust.

[0066] In one embodiment of the present application, Figure 3 and Figure 4 As shown, the pull wire structure 5 includes a first pull wire 51 and a second pull wire 52; the first pull wire 51 is located on one side of the radial direction of the origami structure 3, and one end of the first pull wire 51 is connected to the driving device 4, and the other end is connected to the origami structure 3; the second pull wire 52 is symmetrically arranged on the other side of the radial direction of the origami structure 3, and one end of the second pull wire 52 is connected to the driving device 4, and the other end is connected to the origami structure 3.

[0067] Specifically, the first pull line 51 and the second pull line 52 are distributed on the left and right sides of the origami structure 3 and are both connected to the origami structure 3. When the driving device 4 is started, the first pull line 51 is tightened or loosened, and the second pull line 52 is loosened or tightened, thereby changing the shape of the fish body and realizing the bending and turning of the fish body.

[0068] The connection point between the first pull wire 51 and the driving device 4 and the connection point between the first pull wire 51 and the origami structure 3 are both fixed connection points, that is, the connection point between the first pull wire 51 and the driving device 4 is positioned, and the connection point between the first pull wire 51 and the origami structure 3 is also positioned. Similarly, the connection point between the second pull wire 52 and the driving device 4 is positioned, and the connection point between the second pull wire 52 and the origami structure 3 is also positioned.

[0069] In one embodiment of the present application, Figure 2 and Figure 4 As shown, the driving device 4 includes a steering gear 41 and a steering wheel 42. The steering wheel 42 is arranged on the steering gear 41 so as to rotate along a horizontal plane under the drive of the steering gear 41. The first pull wire 51 and the second pull wire 52 are distributed on both sides of the steering wheel 42 and are both connected to the steering wheel 42.

[0070] Specifically, the first tension wire 51 and the second tension wire 52 are distributed on both sides of the steering disc 42 along the radial direction of the steering disc 42. In one implementation of the present embodiment, when the steering engine 41 is started and drives the steering disc 42 to rotate clockwise, the contact length between the first tension wire 51 and the steering disc 42 increases, the first tension wire 51 is pulled by the steering disc 42 and drives the origami structure 3 to bend in the direction of the first tension wire 51; when the steering engine 41 is started and drives the steering disc 42 to rotate clockwise, the contact length between the second tension wire 52 and the steering disc 42 increases, the second tension wire 52 is pulled by the steering disc 42 and drives the origami structure 3 to bend in the direction of the second tension wire 52.

[0071] like Figure 4 As shown, an arc groove 421 is provided on the outer circumferential surface of the steering wheel 42, and the arc groove 421 cooperates with the first pull wire 51 and the second pull wire 52 to accommodate the first pull wire 51 and the second pull wire 52 when the steering wheel 42 rotates, thereby limiting the first pull wire 51 and the second pull wire 52 to avoid excessive displacement when the first pull wire 51 and the second pull wire 52 are pulled and deformed, thereby ensuring the stability of the bionic robot fish when turning.

[0072] like Figure 2 and Figure 3 As shown, the wire pulling structure 5 also includes a first wire fixing plate 53, which is arranged on the origami structure 3 and can move back and forth axially with the origami structure 3; the first wire pulling wire 51 and the second wire pulling wire 52 are located on both sides of the first wire fixing plate 53 and are both connected to the first wire fixing plate 53.

[0073] Specifically, the position between the first fixing plate 53 and the origami structure 3 is relatively fixed, and the position of the connection point between the first fixing plate and the first pull wire 51 and the second pull wire 52 is relatively fixed, so when the origami structure 3 is extended or retracted, the first fixing plate 53 moves axially synchronously with the origami structure 3. The first fixing plate 53 can increase the degree of interference between the first pull wire 51, the second pull wire 52 and the origami structure 3, ensuring that the tension generated when the first pull wire 51 or the second pull wire 52 is tightened can be stably transmitted to the origami structure 3, thereby ensuring the stability of the bionic robotic fish when turning.

[0074] like Figure 2 and Figure 3 As shown, the wire pulling structure 5 also includes a second wire fixing plate 54, which is arranged on the origami structure 3 and is located between the head 1 and the first wire fixing plate 53; the second wire fixing plate 54 is provided with a first assembly hole and a second assembly hole, the first pull wire 51 passes through the first assembly hole and is loosely matched with the first assembly hole; the second pull wire 52 passes through the second assembly hole and is loosely matched with the second assembly hole.

[0075] Specifically, the second fixing plate 54 is located on the side of the first fixing plate 53 close to the head 1, that is, the first fixing plate 53 is closer to the tail of the bionic robotic fish, and the second fixing plate 54 is closer to the head 1. The second fixing plate 54 and the first fixing plate 53 are arranged at intervals, and the first pull wire 51 and the second pull wire 52 are both assembled with the second fixing plate 54. The clearance fit between the first pull wire 51 and the first assembly hole, and the clearance fit between the second pull wire 52 and the second assembly hole, enable the first pull wire 51 and the second pull wire 52 to be movable relative to the second fixing plate 54; that is, the assembly point between the first pull wire 51 and the second fixing plate 54 is not fixed, and the assembly point between the second pull wire 52 and the second fixing plate 54 is not fixed. When the first pull wire 51 is tightened or the second pull wire 52 is tightened or the origami structure 3 is stretched or contracted, the second fixing plate 54 can move relative to the first pull wire 51 and the second pull wire 52.

[0076] In the present application, the first pull line 51 and the second pull line 52 are installed by two fixing plates, and the first pull line 51 and the second pull line 52 can be fixed in different places, providing more uniform and balanced force transmission; by setting fixing plates at different positions of the fish body, it can be ensured that the pull line structure 5 can effectively control the movement of the fish body in multiple directions. When the swimming direction needs to be adjusted, the two fixing plates can fix the pull lines in different directions respectively, so that the fish body is more stable when adjusting the direction, and reduce the malfunction caused by unevenness or looseness of the first pull line 51 or the second pull line 52.

[0077] Meanwhile, if there is only one fixing plate, the tension and load of the first and second cables 51, 52 will be concentrated at a single point, which may cause excessive stress at that point, thereby affecting the service life of the first and second cables 51, 52 or causing unbalanced movement. By using two fixing plates, the tension of the first and second cables 51, 52 can be dispersed to multiple points, reducing the overload at a single point and improving the reliability and stability of the cable structure 5.

[0078] The cooperation of the first fixing plate 53 and the second fixing plate 54 also helps to ensure the structural symmetry of the design, so that the robot fish maintains balance during propulsion, and avoids asymmetric or unbalanced movement caused by the tension line on one side being too tight or too loose. Especially when high-precision control is required, the two fixing points help to ensure the stability of the entire system.

[0079] In one embodiment of the present application, Figure 1 , Figure 2 and Figure 3 As shown, the earthworm-like variable stiffness bionic robotic fish also includes a dorsal fin 6 , and the dorsal fin 6 is arranged on the second wire fixing plate 54 .

[0080] Specifically, the function of the dorsal fin 6 is to improve the forward stability of the robot fish, especially to prevent the fish body from tilting up and down or rolling during the swimming process; the dorsal fin 6 is arranged on the second fixed line plate 54 which is relatively forward, which can play a better role in the forward process of the robot fish and help to better control the longitudinal stability of the fish body. When the robot fish swims, the dorsal fin 6 can resist the disturbance caused by the water flow and reduce the upside-down flipping or instability caused by the unevenness of the fluid or the reaction force of the water flow; and, compared with the dorsal fin 6 being arranged on the first fixed line plate 53, the dorsal fin 6 is arranged on the second fixed line plate 54 which is relatively forward in this embodiment, which can ensure that the dorsal fin 6 can contact the water flow earlier, help to optimize the direction of the water flow entering the robot fish body, prevent the water flow from forming vortices or unstable local flows at the tail, reduce resistance and improve propulsion efficiency, so as to quickly generate stability during the swimming process and avoid the robot fish from affecting the whole body shape due to the instability of the rear.

[0081] It should be noted that the first fixing plate 53 and the second fixing plate 54 are partially embedded in the origami structure 3 and partially extend outside the origami structure 3, and the portions embedded in the origami structure 3 are provided with ventilation holes 50 (such as Figure 3 As shown), to ensure that the gas can fill the entire inner cavity of the origami structure 3; the second wire fixing plate 54 extends to the part outside the origami structure 3 for installing the dorsal fin 6, the first pull wire 51 and the second pull wire 52; the first wire fixing plate 53 extends to the part outside the origami structure 3 for installing the first pull wire 51 and the second pull wire 52.

[0082] In one embodiment of the present application, the earthworm-like variable stiffness bionic robotic fish also includes a tail fin 7 and two push plate structures 8; the tail fin 7 is arranged at the end of the origami structure 3 away from the head 1; the two push plate structures 8 are symmetrically arranged on both sides of the tail fin 7.

[0083] like Figure 1 , Figure 2 and Figure 5 As shown, in this embodiment, the push plate structure 8 is arranged on both sides of the tail fin 7, and a pointed accommodation space is formed between the two push plate structures 8, and the tail fin 7 is located in the pointed accommodation space; one end of the push plate structure 8 is connected to the tail fin 7, and the other end is a free end. The tail fin 7 is mainly responsible for providing propulsion, and the push plate structures 8 on both sides of the tail fin 7 assist the tail fin 7 to jointly push the water flow, so that the propulsion can be more evenly distributed, avoiding the propulsion force from being too concentrated in a single direction of the tail fin 7, thereby enhancing the overall propulsion efficiency. The push plate structure 8 increases the propulsion area of ​​the water flow and increases the hydrodynamic effect of the tail, which helps to maintain the propulsion of the robot fish at high speed or heavy load, especially when a large thrust is required, the push plate structure 8 can provide additional power support. At the same time, the two push plate structures 8 can help guide the water flow to flow smoothly along the body shape of the robot fish, avoid the water flow from forming unnecessary vortices or turbulence around the tail fin 7, help reduce the instability in fluid dynamics, and make the robot fish swim more smoothly and stably.

[0084] In relatively open waters, the first pull line 51 and the second pull line 52 fixed on the steering disc 42 are connected to the first fixed line plate 53 and the second fixed line plate 54, and the swing of the steering gear 41 drives the tail fin 7 to swing to achieve propulsion; and during the extension and retraction process of the origami structure 3, the tail fin 7 and the push plate structure 8 can imitate the insect feet pushing water, so that the robot fish can be propelled forward without relying on the swing of the tail.

[0085] like Figure 1As shown, the push plate structure 8 includes a flexible connector 83, a first push plate 81 and a second push plate 82; the flexible connector 83 is connected to the tail fin 7, the first push plate 81 is arranged on the flexible connector 83, and the second push plate 82 is arranged on the flexible connector 83 and is located on the side of the first push plate 81 away from the origami structure 3.

[0086] Specifically, one end of the flexible connector 83 is connected to the tail fin 7, and the other end is a free end; the first push plate 81 and the second push plate 82 are arranged side by side on the same side of the flexible connector 83. The first push plate 81 and the second push plate 82 form two independent structures and are connected by the flexible connector 83, so that the push plate structure 8 has a certain flexibility, reducing the rigidity of the push plate structure 8; the pressure and direction of the water flow will change continuously during the swimming process, and the flexible push plate structure 8 can flexibly adjust its shape according to these changes (such as Figure 5 , Figure 6 and Figure 7 As shown in the figure, the robot fish can better cope with different water conditions and reduce fluid resistance. When the robot fish swims at a low speed or turns, the flexible push plate structure 8 can help to make a smooth transition and avoid the rigid push plate from generating excessive unnecessary resistance or water flow disturbance in these situations; the flexibility of the push plate structure 8 enables the push plate structure 8 to push water when the pull wire structure 5 moves.

[0087] The flexible connector 83 can be made of elastic materials such as silicone, which can absorb and disperse the pressure applied by the water flow, reduce the stress concentration that the first push plate 81 and the second push plate 82 may encounter, thereby improving the fatigue resistance and durability of the push plate structure 8, allowing the robot fish to maintain the stability of the water flow during different speeds or turns, reduce sudden changes or abrupt force transmission, and make the swimming process smoother and more natural.

[0088] Figure 6 and Figure 7 As shown, Figure 6 Middle arrow and Figure 7 The arrows in the middle indicate the direction of the fluid (water); when the pneumatic device 2 drives the origami structure 3 to gradually extend toward the tail, the direction of the fluid received by the push plate structure 8 is as follows: Figure 6 As shown in FIG. 1 , the angle between the two push plate structures 8 gradually increases, and the two push plate structures 8 gradually open outward. When the pneumatic device 2 drives the origami structure 3 to gradually retract toward the head, the direction of the fluid on the push plate structure 8 is as follows: Figure 7 As shown, the angle between the two push plate structures 8 gradually decreases, and the two push plate structures 8 gradually close inwards.

[0089] like Figure 1 and Figure 3 As shown, the push plate structure 8 further includes an elastic pad 84 , which is disposed on the flexible connector 83 and located between the first push plate 81 and the second push plate 82 .

[0090] The elastic pad 84 can also limit the first push plate 81 and the second push plate 82. The bonding of the elastic pad 84 on the flexible connector 83 allows the angle and shape between the first push plate 81 and the second push plate 82 to be properly adjusted according to the change of water flow and the motion state of the robot fish; under different water flow conditions, the action of the push plate structure 8 can respond more flexibly, thereby improving the propulsion efficiency and stability of the robot fish.

[0091] At the same time, the elastic pad 84 can effectively disperse and mitigate the reaction force of the water flow on the first push plate 81 and the second push plate 82, avoiding excessive pressure and impact caused by the rigid push plate. The flexible design of the push plate can better alleviate and absorb the impact from the water flow under the action of the water flow, reducing the instability or loss of control of the robot fish caused by excessive reaction force.

[0092] In summary, the present invention provides a kind of earthworm-like variable stiffness bionic robot fish, which includes a head; a pneumatic device, which is arranged in the head; an origami structure, one end of which is axially connected to the head; the pneumatic device is connected to the origami structure and is used to inflate or extract air from the origami structure to drive the origami structure to extend and retract axially; a driving device, which is arranged in the head; and a wire structure, which is respectively connected to the driving device and the origami structure to drive the origami structure to bend under the drive of the driving device. In the present application, the origami structure is combined with the wire-pulling structure, and the pneumatic device is used to inflate and evacuate the origami structure, thereby adjusting the internal pressure of the origami structure and realizing spatial folding and stretching deformation of the origami structure, thereby adjusting the stiffness of the fish body, so that the robot fish can adapt to different task requirements and environmental changes; the wire-pulling mechanism imitates the muscle distribution of the robot fish, pulls the fish body cavity composed of the origami mechanism, and performs a large-scale tail-swinging movement, thereby generating thrust. In operations in confined spaces, the movements of the origami mechanism and the wire-pulling mechanism are coordinated to generate earthworm-like peristaltic swimming, significantly improving the passability in operations in confined spaces; and in the extension and retraction process of the origami structure, the tail fin and the push plate structure can imitate the water pushing of insect feet, so that the robot fish can move forward without relying on tail swinging.

[0093] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A variable stiffness earthworm-like bionic robotic fish, comprising a head, characterized in that: It also includes: A pneumatic device disposed in the head; An origami structure, one axial end of which is connected to the head; the pneumatic device is connected to the origami structure and is used to inflate or evacuate air from the origami structure to drive the origami structure to expand and contract along the axial direction; The driving device is arranged in the head.

2. The earthworm-like variable stiffness bionic robotic fish according to claim 1, characterized in that: The pneumatic device comprises: Gas cylinders; A reversing valve connected to the origami structure; The air pump is arranged between the gas storage bottle and the reversing valve, and is connected to the gas storage bottle and the reversing valve respectively.

3. The earthworm-like variable stiffness bionic robotic fish according to claim 1, characterized in that: It also includes: The pulling wire structure is connected to the driving device and the origami structure respectively, so as to drive the origami structure to bend under the driving of the driving device.

4. The earthworm-like variable stiffness bionic robotic fish according to claim 3, characterized in that: The wire pulling structure comprises: A first pull wire, located on one side of the origami structure in a radial direction, with one end of the first pull wire connected to the driving device and the other end connected to the origami structure; The second pull wire is symmetrically arranged on the other radial side of the origami structure, and one end of the second pull wire is connected to the driving device, and the other end is connected to the origami structure.

5. The earthworm-like variable stiffness bionic robotic fish according to claim 4, characterized in that: The driving device comprises: Steering gear; A steering wheel, arranged on the steering gear, to rotate along a horizontal plane under the drive of the steering gear; The first pull wire and the second pull wire are distributed on both sides of the steering disc and are both connected to the steering disc.

6. The earthworm-like variable stiffness bionic robotic fish according to claim 4, characterized in that: The pull wire structure also includes: The first fixing plate is arranged on the origami structure and can reciprocate along the axial direction with the origami structure; the first pull wire and the second pull wire are located on both sides of the first fixing plate and are both connected to the first fixing plate.

7. The earthworm-like variable stiffness bionic robotic fish according to claim 6, characterized in that: The pull wire structure also includes: A second fixing plate, disposed on the origami structure and located between the head and the first fixing plate; The second wire fixing plate is provided with a first assembly hole and a second assembly hole, the first pull wire passes through the first assembly hole and is loosely matched with the first assembly hole; the second pull wire passes through the second assembly hole and is loosely matched with the second assembly hole.

8. The earthworm-like variable stiffness bionic robotic fish according to claim 1, characterized in that: It also includes: A tail fin, arranged at an end of the origami structure away from the head; Two push plate structures are symmetrically arranged on both sides of the tail fin.

9. The earthworm-like variable stiffness bionic robotic fish according to claim 8, characterized in that: The push plate structure comprises: A flexible connector connected to the tail fin; A first push plate, disposed on the flexible connecting member; The second push plate is arranged on the flexible connecting member and is located on a side of the first push plate away from the origami structure.

10. The earthworm-like variable stiffness bionic robotic fish according to claim 9, characterized in that: The push plate structure also includes: The elastic pad is arranged on the flexible connecting member and is located between the first pushing plate and the second pushing plate.

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