PVC gel efficient composite swing propelling structure for medium and large bionic fishes

Abstract

The invention relates to the technical field of bionic robots, in particular to a PVC gel efficient composite swing propelling structure for medium and large bionic fishes, which comprises a plurality of swing joints connected in series; each swing joint comprises a structural part and two swing units, and each structural part comprises a driving force collecting plate, a cover plate, a bottom plate and a ridge plate; the two swing units are arranged between the cover plate and the bottom plate, and each swing unit comprises a PVC gel driver and a displacement amplification mechanism; one end of the PVC gel driver is fixed to the bottom plate, the other end of the PVC gel driver is connected with the displacement amplifying mechanism through the driving force collecting plate, and the displacement output tail end of the displacement amplifying mechanism makes contact with the boss of the cover plate. The displacement amplification mechanism is used for increasing the width (in the z direction) of the swing joint under the same PVC gel deformation condition so as to maintain or amplify the bending swing angle, so that the body type and the propelling performance of the bionic robotic fish are improved, and the bionic robotic fish has the advantages that the structure and the process are simple, and the swing angle and the bending moment can be well regulated and controlled.

Description

Technical Field

[0001] This application relates to the field of biomimetic robot technology, and in particular to a high-efficiency composite oscillating propulsion structure made of PVC gel for medium and large-sized biomimetic fish. Background Technology

[0002] The design inspiration for robotic fish structures primarily comes from marine fish. With the rapid development of underwater exploration technology in my country, underwater robots, as an integrated system of modern high-tech underwater instruments, have immense potential application value. Currently, the propulsion system of robotic fish still uses electric motors, with most of the energy used to convert the motor's rotational motion into fin flapping. Its advantages include high output speed, large driving force, and convenient control, but it also suffers from disadvantages such as complex structure, stiff movements, low flexibility, and high noise, making it difficult to truly achieve the high efficiency and stealth of fish swimming. Bionic robotic fish, as a combination of fish propulsion mechanisms and robotics technology, provide a new approach for developing novel underwater vehicles, possessing significant research value and application prospects. Once applied, bionic robotic fish will play a crucial role in operations in complex and dangerous underwater environments, reconnaissance, underwater rescue, marine life observation, and archaeology.

[0003] Artificial muscles are novel functional materials capable of sensing external stimuli. They can deform under the influence of an applied electric field, temperature field, or solution ion concentration field, exhibiting behaviors such as bending, extending, twisting, and contracting. They can also withstand certain loads, thus enabling actuation. Furthermore, they are lightweight and inexpensive, leading to their increasingly significant applications in machinery, medical, and military fields. Using flexible smart materials as actuators for biomimetic robotic fish allows for better miniaturization, high flexibility, and low noise. Typical artificial muscle materials, such as dielectric elastomers (DE) and ionomer-metal composites (IPMC), are widely studied. IPMC materials offer advantages such as low driving voltage (1-5V), flexibility, lightweight, and good biocompatibility, but suffer from lower driving force and slower response speed. DE materials offer advantages such as high output force and fast response speed, but their high operating voltage (up to several kilovolts) and susceptibility to breakdown limit their widespread use in soft robot actuation. PVC gel (Poly vinylchloride gel, PVC gel) is also a new type of artificial muscle material. It has high strain (above 13%), fast response speed (0-100Hz), wide operating frequency band, light weight, operating voltage between ionomers and dielectric elastomers, and large driving force (100N), making it very suitable for biomimetic robot drive design.

[0004] Existing technology discloses a biomimetic fish tail structure driven by PVC gel artificial muscles, which uses two rows of stacked PVC gel actuators connected in series on the left and right sides to alternately contract and extend to achieve bending and oscillation. The PVC gel stacked actuators directly transmit force to the joint base plate through bosses. Since the maximum strain of the actuators is limited (about 10%), increasing the width of the actuators will lead to a decrease in the oscillation angle of the biomimetic fish tail and a weakening of propulsion performance. Therefore, the designable width range is relatively limited (1-3cm), which restricts the improvement of the robotic fish's body size and propulsion performance. Summary of the Invention

[0005] This application provides a high-efficiency composite oscillating propulsion structure for medium and large-sized biomimetic fish using PVC gel. It utilizes a displacement amplification mechanism to increase the width (z-direction) of the oscillating joint under the same PVC gel deformation conditions, while maintaining or amplifying the bending oscillation angle, thereby improving the size and propulsion performance of the biomimetic robotic fish. It has the advantages of simple structure and process, and good adjustability of oscillation angle and bending moment.

[0006] To address the aforementioned technical problems, this application provides a high-efficiency composite oscillating propulsion structure using PVC gel for medium to large-sized biomimetic fish, comprising: multiple oscillating joints connected in series; each oscillating joint includes a structural component and two oscillating units; the structural component includes a driving force gathering plate, a parallel cover plate and a bottom plate, and a ridge plate vertically disposed between the cover plate and the bottom plate; one end of the ridge plate is connected to the cover plate via a hinge, and the other end is fixed to the bottom plate; the two oscillating units are disposed between the cover plate and the bottom plate, and the two oscillating units are symmetrical about the longitudinal central axis of the ridge plate; each oscillating unit includes a PVC gel actuator and a displacement amplification mechanism; one end of the PVC gel actuator is fixed to the bottom plate, and the other end is connected to the displacement amplification mechanism via the driving force gathering plate, and the displacement output end of the displacement amplification mechanism contacts the boss of the cover plate.

[0007] In some exemplary embodiments, the deformation and driving force generated by the extension and contraction of the PVC gel actuator act on the displacement amplification mechanism. After displacement amplification and force reduction, the force is applied to the cover plate of the swing joint. When multiple swing joints are connected in series, the cover plate of the swing joint is the base plate of the swing joint connected in series with it. That is, after displacement amplification and force reduction, the force is applied to the base plate of the swing joint connected in series with it. The PVC gel actuators in adjacent swing units alternately extend or shorten, causing the swing joint to bend and swing, thereby causing the multiple swing joints connected in series to swing left and right rhythmically to simulate fish tail propulsion.

[0008] In some exemplary embodiments, the formula for displacement amplification is:

[0009]

[0010] Where S is the amplified displacement, s is the deformation caused by the extension and contraction of the PVC gel actuator, L is 1 / 2 of the width of the swing joint, d is the length of the displacement output end from the longitudinal central axis of the spine plate; Ld is the lever length of the displacement amplification mechanism, and w is the length of the driving force convergence position from the side of the driving force convergence position.

[0011] The formula for reducing force is:

[0012]

[0013] Where f is the reduced force and F is the driving force.

[0014] In some exemplary embodiments, one end of the driving force concentrator is connected to the PVC gel actuator, and the other end is connected to the displacement amplification mechanism via a hinge; the driving force concentrator is used to collect the deformation and driving force generated by the extension and contraction of the PVC gel actuator, and to apply the collected force to the displacement amplification mechanism.

[0015] In some exemplary embodiments, the displacement amplification mechanism includes a first connecting rod, a lever, and a second connecting rod; the first connecting rod is perpendicular to the base plate, and one end of the first connecting rod is fixedly connected to the base plate, while the other end is connected to the lever via a hinge; the lever is parallel to the cover plate, and the end of the lever away from the first connecting rod is fixedly connected to the second connecting rod, and the displacement output end of the second connecting rod contacts the boss of the cover plate.

[0016] In some exemplary embodiments, the lever is located between the PVC gel actuator and the cover plate; a gap exists between the lever and the PVC gel actuator.

[0017] In some exemplary embodiments, the displacement amplification mechanism is a sinking displacement amplification mechanism; the PVC gel actuator includes a plurality of PVC gel driving units; there is a lateral gap between adjacent PVC gel driving units for placing the sinking displacement amplification mechanism; the driving force gathering plate is an inverted driving force gathering plate; the lever is located in the lateral gap between adjacent PVC gel driving units; there is a gap between the lever and the PVC gel actuator.

[0018] In some exemplary embodiments, the swing joints of the displacement amplification mechanism with a sinking design are connected in series to form a biomimetic fish tail; the biomimetic fish tail includes multiple series-connected double PVC gel composite bending swing joints; the double PVC gel composite bending swing joint is formed by connecting two swing joints of the displacement amplification mechanism with a sinking design; the cover plates of the two swing joints in the double PVC gel composite bending swing joint are placed opposite each other and the two swing joints share a cover plate; or, the cover plates of the two swing joints in the double PVC gel composite bending swing joint are removed, the spine plates of the two swing joints are connected by flexible hinges, the displacement output ends of the displacement amplification mechanism of the two swing joints are connected by flexible hinges to form a zigzag hinge displacement amplification mechanism, and the bottom plates of adjacent swing joints are connected in series by fixed connection to form a biomimetic fish tail.

[0019] In some exemplary embodiments, in each swing joint, two PVC gel actuators are integrally molded in two swing units; the integrally molded PVC gel actuators have gaps in both the width and height directions of the swing joint, the gap in the width direction is used to arrange the displacement amplification mechanism of the sinking design, and the gap in the height direction is used to arrange the ridge plate and the wire.

[0020] In some exemplary embodiments, the hinge includes a pin-type hinge and a flexible hinge; the flexible hinge is a flexible hinge integrally manufactured from plastic; or, the flexible hinge includes an elastic metal sheet and two oppositely arranged plastic parts, with the two ends of the elastic metal sheet respectively inserted into the oppositely arranged plastic parts to achieve flexible rotation.

[0021] The technical solution provided in this application has at least the following advantages:

[0022] This application provides a high-efficiency composite oscillating propulsion structure using PVC gel for medium to large-sized bionic fish, comprising: multiple oscillating joints connected in series; each oscillating joint includes a structural component and two oscillating units; the structural component includes a driving force gathering plate, a parallel cover plate and a bottom plate, and a ridge plate vertically disposed between the cover plate and the bottom plate; one end of the ridge plate is connected to the cover plate via a hinge, and the other end is fixed to the bottom plate; the two oscillating units are disposed between the cover plate and the bottom plate, and the two oscillating units are symmetrical about the longitudinal central axis of the ridge plate; each oscillating unit includes a PVC gel actuator and a displacement amplification mechanism; one end of the PVC gel actuator is fixed to the bottom plate, and the other end is connected to the displacement amplification mechanism via the driving force gathering plate, and the displacement output end of the displacement amplification mechanism contacts the boss of the cover plate. The high-efficiency composite oscillating propulsion mechanism using PVC gel designed in this application can expand the dimensions of the robotic fish in the length, width, and height directions, while reliably controlling key performance aspects such as oscillation moment and oscillation angle, realizing high-efficiency composite oscillation of medium to large-sized bionic fish. It can be used for the development and application of medium to large-sized flexible bionic robotic fish and has significant promotional value. Attached Figure Description

[0023] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments, and unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0024] Figure 1 This is a schematic diagram of the structure of a swing joint provided in an embodiment of this application.

[0025] Figure 2 This is a schematic diagram of a hinge structure provided in an embodiment of this application.

[0026] Figure 3 A hinge structure diagram provided for another embodiment of this application.

[0027] Figure 4 This is a schematic diagram of the displacement amplification mechanism provided in one embodiment of this application.

[0028] Figure 5 A cross-sectional view (AA) of the PVC gel bending and swinging joint of the displacement amplification mechanism provided in an embodiment of this application.

[0029] Figure 6 This is a three-dimensional view of a semi-joint of a PVC gel bending and swinging joint provided by a displacement magnification mechanism in an embodiment of this application.

[0030] Figure 7 This is a diagram of a multi-jointed fishtail of a PVC gel bending and swinging joint, which is part of a displacement amplification mechanism provided in an embodiment of this application.

[0031] Figure 8 This is a schematic diagram of the structure of a double PVC gel composite bending and swinging joint provided in an embodiment of this application.

[0032] Figure 9 This is a diagram of a multi-jointed fishtail with a double PVC gel composite bending and swinging joint provided in an embodiment of this application.

[0033] Figure 10 This is a schematic diagram showing the distribution of PVC gel and structural components in a medium-to-large bionic fish tail according to an embodiment of this application. Detailed Implementation

[0034] As can be seen from the background technology, the existing biomimetic structures have a relatively limited range of designed widths (1-3cm), which restricts the improvement of the size of the robotic fish and its propulsion performance.

[0035] To address the aforementioned technical problems, this application provides a high-efficiency composite oscillating propulsion structure using PVC gel for medium to large-sized biomimetic fish. The structure includes: multiple oscillating joints connected in series; each oscillating joint includes a structural component and two oscillating units; the structural component includes a driving force concentrator plate, parallel cover plates and bottom plates, and a ridge plate vertically disposed between the cover plates and bottom plates; one end of the ridge plate is connected to the cover plate via a hinge, and the other end is fixed to the bottom plate; the two oscillating units are disposed between the cover plate and the bottom plate, and the two oscillating units are symmetrical about the longitudinal central axis of the ridge plate; each oscillating unit includes a PVC gel actuator and a displacement amplification mechanism; one end of the PVC gel actuator is fixed to the bottom plate, and the other end is connected to the displacement amplification mechanism via the driving force concentrator plate, with the displacement output end of the displacement amplification mechanism contacting the boss of the cover plate. This application provides a high-efficiency composite oscillating propulsion structure using PVC gel for medium to large-sized biomimetic fish, proposing to utilize a displacement amplification mechanism to increase the joint width (z-direction) under the same PVC gel deformation conditions while maintaining or amplifying the bending oscillation angle, thereby improving the body shape and propulsion performance of the biomimetic robotic fish. It has the advantages of simple structure and process, and good adjustability of oscillation angle and bending moment.

[0036] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0037] This application provides a high-efficiency composite oscillating propulsion structure made of PVC gel for medium to large-sized biomimetic fish, comprising: multiple oscillating joints connected in series; each oscillating joint includes a structural component and two oscillating units, and the multiple oscillating joints are sequentially connected in series to form a flexible, curved, oscillating biomimetic fish tail. Figure 1 As shown, the structural components include a driving force gathering plate 11 (sliding joint boss), a parallel cover plate 14 and a base plate 15, and a ridge plate 16 vertically disposed between the cover plate 14 and the base plate 15; one end of the ridge plate 16 is connected to the cover plate 14 via a hinge 13 connecting the ridge plate 16 and the cover plate 14 (or the base plate 15 of the next swing joint), and the other end is fixed to the base plate 15; two swing units are disposed between the cover plate 14 and the base plate 15, and the two swing units are symmetrical about the longitudinal central axis of the ridge plate 16; each swing unit includes a PVC gel actuator 12 and a displacement amplification mechanism 22; one end of the PVC gel actuator 12 is fixed to the base plate 15, and the other end is connected to the displacement amplification mechanism 22 via the driving force gathering plate 11, and the displacement output end of the displacement amplification mechanism 22 contacts the boss of the cover plate 14.

[0038] This application provides a high-efficiency composite swing propulsion structure for medium and large-sized bionic fish using PVC gel. The displacement amplification mechanism 22 increases the width (z direction) of the swing joint under the same PVC gel deformation conditions, thereby maintaining or amplifying the bending swing angle and improving the size and propulsion performance of the bionic robotic fish. Figure 1 The middle cover plate 14 can be the base plate 15 of the connected swing joint, 21 is the hinge connecting the displacement amplification mechanism 22, 23 is the hinge connecting the driving force gathering plate 11 and the displacement amplification mechanism 22, and 24 is the boss of the cover plate, wherein the displacement amplification mechanism 22 is in contact with the boss 24 of the cover plate.

[0039] In some embodiments, the hinge includes a pin-type hinge and a flexible hinge; the flexible hinge in the swing joint, especially in the displacement amplification mechanism, may be a pin-type hinge. The flexible hinge is a flexible hinge integrally machined from plastic; or, the flexible hinge includes an elastic metal sheet and two oppositely arranged plastic parts, with the two ends of the elastic metal sheet respectively inserted into the oppositely arranged plastic parts to achieve flexible rotation.

[0040] Specifically, to simplify the manufacturing and installation process, flexible hinges can be manufactured using one-piece plastic printing, such as... Figure 2 and Figure 3 As shown, Figure 2 The 25th hinge is a flexible hinge that can be printed entirely from plastic; to increase the durability of the hinge, a flexible metal sheet can be inserted into the plastic to achieve a flexible hinge. Figure 3 26 is a metal piece inserted into a plastic block.

[0041] In some embodiments, the deformation and driving force generated by the extension and retraction of the PVC gel actuator 12 act on the displacement amplification mechanism 22. After displacement amplification and force reduction, the force is applied to the cover plate 14 of the swing joint. When multiple swing joints are connected in series, the cover plate 14 of the swing joint is the base plate 15 of the swing joint connected in series with it. That is, after displacement amplification and force reduction, the force is applied to the base plate 15 of the swing joint connected in series with it. The PVC gel actuators 12 in adjacent swing units alternately extend or shorten, causing the swing joint to bend and swing, thereby causing the multiple swing joints connected in series to swing left and right rhythmically to simulate fish tail propulsion.

[0042] Since the strain of the PVC gel actuator 12 is limited (~10%), increasing the width of the PVC gel actuator 12 or the position w of the driving force gathering plate 11 (sliding joint boss) will inevitably reduce the bending angle and decrease the propulsion performance. Therefore, this application proposes to use a displacement amplification mechanism 22 to amplify the driving displacement and compensate for the reduction in bending angle caused by the increase in width. The displacement amplification mechanism 22 will weaken the driving force transmitted to the cover plate 14 or the bottom plate 15 of the next swing joint. This is compensated by increasing the area by increasing the width and length of the actuator. The relationship between the deformation s and the driving force F is as follows: Figure 4 As shown.

[0043] In some embodiments, the formula for displacement amplification is:

[0044]

[0045] Where S is the amplified displacement, s is the deformation caused by the extension and contraction of the PVC gel actuator, L is 1 / 2 of the width of the swing joint, d is the length of the displacement output end from the longitudinal central axis of the spine plate; Ld is the length of the lever of the displacement amplification mechanism, and w is the length of the driving force convergence position from the side of the driving force convergence position.

[0046] The formula for reducing force is:

[0047]

[0048] Where f is the reduced force and F is the driving force.

[0049] like Figure 4 As shown, the length of the lever of the displacement amplification mechanism 22 is Ld, and its rotation center is set at one end of the lever. The deformation and driving force generated by the extension and retraction of the PVC gel actuator 12 are concentrated at the middle position of the lever through the driving force collection plate 11, and the distance from the rotation hinge is w. The displacement is amplified through the other end of the lever and then acts on the cover plate, with an amplification factor of (Ld) / w.

[0050] In some embodiments, one end of the driving force gathering plate 11 is connected to the PVC gel actuator 12, and the other end is connected to the displacement amplification mechanism 22 via a hinge; the driving force gathering plate 11 is used to gather the deformation and driving force generated by the extension and retraction of the PVC gel actuator 12, and apply the gathered force to the displacement amplification mechanism 22.

[0051] Specifically, to ensure the stability of the swing joint drive, the boss of the drive force collection plate 11 is usually located in the middle of the PVC gel actuator 12.

[0052] Please continue reading. Figure 1 In some embodiments, the displacement amplification mechanism 22 includes a first connecting rod (a vertical connecting rod on both sides of the two PVC gel actuators 12), a lever (a horizontal rod horizontally disposed above the PVC gel actuators 12), and a second connecting rod (a vertical connecting rod close to the ridge plate 16 and connected to the cover plate 14); the first connecting rod is perpendicular to the base plate 14, and one end of the first connecting rod is fixedly connected to the base plate 14, and the other end is connected to the lever via a hinge; the lever is parallel to the cover plate 14, and the end of the lever away from the first connecting rod is fixedly connected to the second connecting rod, and the displacement output end of the second connecting rod contacts the boss of the cover plate 14.

[0053] In some embodiments, the lever is located between the PVC gel actuator 12 and the cover plate 14; there is a gap between the lever and the PVC gel actuator 12. It should be noted that this gap is mainly due to the expansion and contraction deformation of the PVC laminate. When bending, interference may occur between the lever and the PVC. Therefore, a gap is reserved between the lever and the PVC gel actuator 12.

[0054] like Figure 5 As shown, in some embodiments, the displacement amplification mechanism 22 adopts a sinking displacement amplification mechanism; the PVC gel actuator 12 includes a plurality of PVC gel driving units; there is a lateral gap between adjacent PVC gel driving units for placing the sinking displacement amplification mechanism; the driving force gathering plate 11 adopts an inverted driving force gathering plate; the lever is located in the lateral gap between adjacent PVC gel driving units; there is a gap between the lever and the PVC gel actuator 12.

[0055] Figure 6 This is a three-dimensional view of the semi-joint of the pivot joint. Figure 7 This is a diagram of a multi-jointed fishtail. Figure 7 In the middle, 3 represents the PVC gel bending and swinging joint that sinks under the displacement amplification mechanism. Figure 5 In the diagram, 31 is a downward-sinking displacement amplification mechanism, and 32 is an inverted drive force gathering plate (hinge). After adding the displacement amplification mechanism 22, the gap between the PVC gel actuator 12 and the cover plate 14 increases. In order to reduce the gap and increase the drive power density, the PVC gel is divided into blocks, and the lever 31 of the displacement amplification mechanism is downward-sinking between the PVC gel actuators 12. The corresponding drive force gathering plate 32 adopts an inverted structure and is connected to the lever 31 through a hinge.

[0056] Specifically, such as Figure 6 As shown, in order to reduce the large gap h2 generated by the displacement amplification mechanism in the swing joint, the joint is divided into multiple unit blocks along the height direction (y direction). The lever of the displacement amplification mechanism is placed in the gap between the PVC gel unit blocks, and the gap h2 is reduced by the sinking design.

[0057] Assuming the initial installation height h1 of the PVC gel used is ±ε after energization, the porosity h2 should not be less than 2ε(L / d)h1. Connecting the bending and swinging joints 3 of the PVC gel, which are lowered by the displacement amplification mechanism, end to end in series can form a biomimetic fish tail. Figure 7 As shown.

[0058] like Figure 8 and Figure 9As shown, in some embodiments, the swing joints of the displacement amplification mechanism with a sinking design are connected in series in a head-to-tail order to form a bionic fish tail; the bionic fish tail includes a plurality of series-connected double PVC gel composite bending swing joints 4; the double PVC gel composite bending swing joint 4 is formed by connecting two swing joints of the displacement amplification mechanism with a sinking design; in the double PVC gel composite bending swing joint 4, the cover plates of the two swing joints are placed opposite to each other and the two swing joints share a cover plate; or, as Figure 8 shown, the cover plates of the two swing joints in the double PVC gel composite bending swing joint 4 are removed, the spine plates of the two swing joints are connected by a spine plate flexible hinge 41, and the displacement output ends of the displacement amplification mechanisms of the two swing joints are connected by a flexible hinge to form a zigzag hinge displacement amplification mechanism, as Figure 8 shown, 42 is the center hinge of the zigzag amplification mechanism. The bottom plates 15 of adjacent swing joints are connected in series by fixed connections to form a bionic fish tail.

[0059] As Figure 8 shown, the swing angle and bending moment of the swing joint can be flexibly adjusted. Increasing the width 2w and length of the PVC gel actuator 12 can increase the driving force and thus increase the bending moment; the swing joint adjusts the amplified displacement and thus increases the swing angle through the rod length L - d of the displacement amplification mechanism, the distance d from the displacement output end to the central spine plate, and the driving force concentration position w; the swing joint adjusts the porosity in the length direction (x-direction) of the fish tail h2 / (h1 + h2) through the half-width L of the joint and the distance d from the displacement output end to the central spine plate. The smaller the value, the more compact the fish tail structure and the higher the swing propulsion power. The composite bending swing joint is simpler to process, and the upper and lower bottom plates are connected in series by fixed connections to form a bionic fish tail.

[0060] In some embodiments, in the two swing units of each swing joint, the two PVC gel actuators adopt an integrated molding design; the integrated molding design of the PVC gel actuator has gaps in both the width direction and the height direction of the swing joint. The gap in the width direction is used to arrange the displacement amplification mechanism with a sinking design, and the gap in the height direction is used to arrange the spine plate and wires.

[0061] Figure 10 Shows a schematic diagram of the distribution of PVC gel and structural plate parts in a medium and large bionic fish tail; where, 5 is the medium and large bionic fish tail, 51 is the x - z plane view of the bionic fish tail, 52 is the x - y plane view of the bionic fish tail, 53 is a single joint of the bionic fish tail, 54 is the "zigzag" hinge displacement amplification mechanism, 55 is the lateral gap for placing the "zigzag" hinge displacement amplification mechanism, 56 is the longitudinal gap for placing the spine plate, and 57 is the partition-connected PVC gel drive unit (partition-connected PVC gel artificial muscle plane). As Figure 10As described above, the left and right sets of PVC gel drive units 57 can be integrally manufactured, with gaps evenly arranged along the joint width (z-direction) and height (y-direction). The lateral gap 55 in the width direction is mainly used to arrange the "ji"-shaped hinge displacement amplification mechanism 54, while the longitudinal gap 56 in the height direction is mainly used to arrange the ridge plate 16, wires, etc. For the design of medium and large-sized bionic fish tails 5, the "ji"-shaped hinge displacement amplification mechanism 54 can expand the scale of the fish body in the width (z-direction) direction (>10 cm), the layout of muscle segments can expand the scale in the height (y-direction) direction (>50 cm), and increasing the porosity in the length (x-direction) direction can improve the propulsion efficiency and increase the scale in the length direction (>100 cm).

[0062] Specifically, the hinges used in the joints include, but are not limited to, pin hinges and flexible hinges, etc. The flexible hinge can be integrally processed from plastic, with the thickness reduced at the rotating part to increase flexibility; or a metal elastic sheet can be inserted into the plastic to achieve flexible rotation and improve durability. Multiple PVC gel-driven bending and swinging joints with displacement amplification are sequentially connected in series by pin hinges at the head and tail to form a bionic fish tail.

[0063] The following will introduce the high-efficiency composite swinging propulsion structure of medium and large-sized bionic fish using PVC gel provided by the present application through specific embodiments in detail.

[0064] Embodiment 1

[0065] Please refer to Figures 5 to 7 , four standard rectangular area-sized PVC gel drivers 12 are manufactured by the lamination method, the bottom plate 15 and the ridge plate 16 are manufactured by 3D printing, the displacement amplification mechanism (lever 31) with a sinking design and its hinge are manufactured by 3D printing, and the driving force converging plate 32 with an inverted structure and its hinge are also manufactured by 3D printing.

[0066] The displacement amplification mechanism with a sinking design and the driving force converging plate 32 with an inverted structure are installed and combined through pin hinges. On the left and right sides of the bottom plate 15, two PVC gel drive blocks are respectively placed on the bottom plate 15, and then the combined structure of the displacement amplification mechanism with a sinking design and the driving force converging plate 32 with an inverted structure is placed on the PVC gel blocks. The displacement amplification mechanism with a sinking design is fixed to the outside of the bottom plate 15 to form a PVC gel bending and swinging joint 3 with a single displacement amplification mechanism sinking (hereinafter referred to as the bending and swinging joint 3).

[0067] Connect two bending and swinging joints 3 end to end, that is, connect the bottom plate 15 of one joint to the ridge plate 16 of the next joint, and connect them through a hinge 13, which can be a pin hinge. During the installation process, ensure that the PVC gel has a certain pre-compression force, and the displacement of compression and shrinkage is usually εh1. Through pre-compression installation, ensure the stable installation of the overall structure of the PVC gel, and at the same time meet the requirements of elongation and shrinkage deformation during the bending process. Install multiple bending and swinging joints 3 in series in sequence to form a bionic fish tail.

[0068] Embodiment 2

[0069] Please refer to Figure 10 , fabricate multiple PVC gel actuators 12; integrally print the bottom plate 15 and the ridge plate 16 respectively by 3D printing method, and connect the ridge plates of two T-shaped (bottom plate and ridge plate) structures through metal sheets to form a flexible hinge; print the driving force collecting plate 32 with an inverted structure and the "ji" - shaped hinge displacement amplification mechanism 54 by 3D printing method.

[0070] First, install the driving force collecting plate 32 with a sinking structure and the "ji" - shaped hinge displacement amplification mechanism 54 through a pin hinge and fix them between the bottom plates 15 of two T-shaped structures. Then, stack and pre-compress multiple PVC gel actuators 12 and install them between the driving force collecting plate 32 and the bottom plate 15 to ensure the stability of the installation. Fixing the bottom plates 15 of multiple fabricated joints together can form a bionic fish tail.

[0071] Please refer to Figure 10 , in order to further expand the scale of the bionic robotic fish in the height direction (y direction), multiple PVC gel actuators 12 (also called PVC gel blocks) and the "ji" - shaped hinge displacement amplification mechanism 54 can be arranged in the height direction.

[0072] Figure 10 Shows a schematic diagram of the distribution of PVC gel and structural components in a medium and large - sized bionic fish tail. Among them, 5 is a medium and large - sized bionic fish tail, 51 is the x - z plane view of the bionic fish tail, 52 is the x - y plane view of the bionic fish tail, 53 is a single joint of the bionic fish tail, 54 is the "ji" - shaped hinge displacement amplification mechanism, 55 is the lateral gap for placing the "ji" - shaped hinge displacement amplification mechanism, 56 is the longitudinal gap for placing the ridge plate, and 57 is the PVC gel drive unit connected in zones (the plane of the PVC gel artificial muscle connected in zones).

[0073] Integrated manufacturing of a PVC gel film with patterned openings can integrally manufacture the multiple PVC gel blocks distributed along the height direction. During joint fabrication, first stack and install the PVC gel blocks on a T-shaped structure, and then install the driving force collection plate 32 of the sinking structure and the "ji" - shaped hinge displacement amplification mechanism 54 on the bottom plate to form an integrated large-scale bionic fish tail single joint 53. Fixing the bionic fish tail single joints 53 in sequence according to the head-to-tail order forms a medium and large-sized bionic fish tail 5.

[0074] With the above technical solutions, the embodiment of the present application provides a high-efficiency composite swing propulsion structure for medium and large-sized bionic fish using PVC gel, including: multiple series-connected swing joints; each swing joint includes a structural member and two swing units, and multiple swing joints are serially connected in sequence to form a flexible and bending swing bionic fish tail. The structural member includes a driving force collection plate 11, parallel cover plates 14 and bottom plates 15, and a ridge plate 16 vertically disposed between the cover plate 14 and the bottom plate 15; one end of the ridge plate 16 is connected to the cover plate 14 through a hinge 13 connecting the ridge plate and the cover plate, and the other end is fixed to the bottom plate 15; the two swing units are disposed between the cover plate 14 and the bottom plate 15, and the two swing units are symmetric about the longitudinal central axis of the ridge plate 16; each swing unit includes a PVC gel actuator 12 and a displacement amplification mechanism 22; one end of the PVC gel actuator 12 is fixed on the bottom plate 15, and the other end is connected to the displacement amplification mechanism 22 through the driving force collection plate 11, and the displacement output end of the displacement amplification mechanism 22 contacts the boss of the cover plate 14. The designed PVC gel high-efficiency composite swing propulsion mechanism of the present application can expand the scale in the three directions of the length, width and height of the robotic fish, and at the same time realize reliable regulation of key performances such as swing bending moment and swing angle, achieve high-efficiency composite swing of medium and large-sized bionic fish, and can be used for the development and application of medium and large-sized flexible bionic robotic fish, having important popularization value.

[0075] Those of ordinary skill in the art can understand that the above embodiments are specific embodiments for implementing the present application, and in practical applications, various changes can be made in form and details without departing from the spirit and scope of the present application. Any person skilled in the art can make their own changes and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application should be subject to the scope defined by the claims.

Claims

1. A high-efficiency composite oscillating propulsion structure using PVC gel for medium to large-sized biomimetic fish, characterized in that, include: Multiple tandem pivot joints; Each swing joint includes a structural component and two swing units; The structural component includes a driving force gathering plate, a parallel cover plate and a bottom plate, and a ridge plate vertically disposed between the cover plate and the bottom plate; one end of the ridge plate is connected to the cover plate by a hinge, and the other end is fixed to the bottom plate; Two swing units are disposed between the cover plate and the bottom plate, and the two swing units are symmetrical about the longitudinal central axis of the ridge plate; Each swing unit includes a PVC gel actuator and a displacement amplification mechanism; one end of the PVC gel actuator is fixed to the base plate, and the other end is connected to the displacement amplification mechanism through a driving force collection plate, and the displacement output end of the displacement amplification mechanism contacts the boss of the cover plate.

2. The high-efficiency composite oscillating propulsion structure for medium and large-sized biomimetic fish using PVC gel as described in claim 1, characterized in that, The deformation and driving force generated by the extension and contraction of the PVC gel actuator act on the displacement amplification mechanism. After displacement amplification and force reduction, the force is applied to the cover plate of the swing joint. When multiple swing joints are connected in series, the cover plate of the swing joint is the base plate of the swing joint connected in series with it. That is, after displacement amplification and force reduction, the force is applied to the base plate of the swing joint connected in series with it. The PVC gel actuators in adjacent swing units alternately extend or shorten, causing the swing joint to bend and swing, thereby causing multiple swing joints connected in series to swing left and right rhythmically to simulate fish tail propulsion.

3. The high-efficiency composite oscillating propulsion structure for medium and large-sized biomimetic fish using PVC gel as described in claim 2, characterized in that, The formula for displacement amplification is: Where S is the amplified displacement, s is the deformation caused by the extension and contraction of the PVC gel actuator, L is 1 / 2 of the width of the swing joint, d is the length of the displacement output end from the longitudinal central axis of the spine plate; Ld is the lever length of the displacement amplification mechanism, and w is the length of the driving force convergence position from the side of the driving force convergence position. The formula for reducing force is: Where f is the reduced force and F is the driving force.

4. The high-efficiency composite oscillating propulsion structure for medium and large-sized biomimetic fish using PVC gel as described in claim 1, characterized in that, One end of the driving force collecting plate is connected to the PVC gel actuator, and the other end is connected to the displacement amplification mechanism via a hinge; The driving force gathering plate is used to gather the deformation and driving force generated by the expansion and contraction of the PVC gel actuator, and apply the gathered force to the displacement amplification mechanism.

5. The high-efficiency composite oscillating propulsion structure for medium and large-sized biomimetic fish using PVC gel according to claim 1, characterized in that, The displacement amplification mechanism includes a first connecting rod, a lever, and a second connecting rod; The first connecting rod is perpendicular to the base plate, and one end of the first connecting rod is fixedly connected to the base plate, while the other end is connected to the lever via a hinge; The lever is parallel to the cover plate, and the end of the lever away from the first connecting rod is fixedly connected to the second connecting rod. The displacement output end of the second connecting rod contacts the boss of the cover plate.

6. The high-efficiency composite oscillating propulsion structure for medium and large-sized biomimetic fish using PVC gel according to claim 5, characterized in that, The lever is located between the PVC gel actuator and the cover plate; There is a gap between the lever and the PVC gel actuator.

7. The high-efficiency composite oscillating propulsion structure for medium and large-sized biomimetic fish using PVC gel according to claim 5, characterized in that, The displacement amplification mechanism is a sinking displacement amplification mechanism; the PVC gel actuator includes several PVC gel driving units; there is a lateral gap between adjacent PVC gel driving units for placing the sinking displacement amplification mechanism. The driving force collecting plate adopts an inverted structure. The lever is located in the lateral gap between adjacent PVC gel drive units; There is a gap between the lever and the PVC gel actuator.

8. The high-efficiency composite oscillating propulsion structure for medium and large-sized biomimetic fish using PVC gel according to claim 7, characterized in that, The swing joints of the displacement amplification mechanism with a sinking design are connected in series in a head-to-tail sequence to form a biomimetic fish tail. The bionic fish tail consists of multiple tandem double PVC gel composite bending and swinging joints; The dual PVC gel composite bending swing joint is composed of two swing joints connected by a displacement amplification mechanism with a sinking design. In the dual PVC gel composite bending and swinging joint, the cover plates of the two swinging joints are placed opposite each other and the two swinging joints share a cover plate; or, the cover plates of the two swinging joints in the dual PVC gel composite bending and swinging joint are removed, the spine plates of the two swinging joints are connected by flexible hinges, the displacement output ends of the displacement amplification mechanisms of the two swinging joints are connected by flexible hinges to form a zigzag hinge displacement amplification mechanism, and the base plates of adjacent swinging joints are connected in series by fixed connection to form a biomimetic fish tail.

9. The high-efficiency composite oscillating propulsion structure for medium and large-sized biomimetic fish using PVC gel according to claim 7, characterized in that, In each swing joint, two PVC gel actuators are designed as a single piece in the two swing units; The PVC gel actuator with one-piece molding design has gaps in both the width and height directions of the swing joint. The gap in the width direction is used to arrange the displacement amplification mechanism of the sinking design, and the gap in the height direction is used to arrange the ridge plate and wires.

10. The high-efficiency composite oscillating propulsion structure for medium and large-sized biomimetic fish using PVC gel according to claim 1, characterized in that, The hinges include pin-type hinges and flexible hinges; The flexible hinge is a flexible hinge made of one piece of plastic; or, the flexible hinge includes an elastic metal sheet and two oppositely arranged plastic parts, with the two ends of the elastic metal sheet respectively inserted into the oppositely arranged plastic parts to achieve flexible rotation.

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