A bionic manta ray robot with foldable fins and its control method

Abstract

The present invention belongs to the technical field related to underwater bionic robots and discloses a bionic manta ray robot with foldable fins and a control method thereof. The bionic manta ray robot with foldable fins comprises a main frame, foldable fins mounted on either side of the main frame, and a flexible skin covering the foldable fins. The foldable fins comprise a flapping mechanism, a folding mechanism, and a driving mechanism. The flapping mechanism is rotatably connected to the main frame and is configured to achieve up and down oscillation of the foldable fins through rotation. The folding mechanism is provided on the flapping mechanism and is configured as a retractable structure along the span of the flapping mechanism. The flexible skin is connected to the folding mechanism. The driving mechanism is mounted on the main frame and connected to the folding mechanism, and is configured to drive the folding mechanism to retract and extend along the span to achieve length variation of the foldable fins. This invention structurally expands the pectoral fin function of the bionic manta ray robot, thereby improving the manta ray robot's mobility and agility.

Description

Technical Field

[0001] The present invention belongs to the technical field related to underwater bionic robots, and more specifically, relates to a bionic manta ray robot with foldable fins and a control method thereof. Background Art

[0002] Manta rays, with their disc-shaped bodies and symmetrical, triangular, wing-shaped pectoral fins, possess excellent stability, low environmental disturbances, superior three-dimensional maneuverability, and high efficiency. Research has shown that manta rays' broad, flat, wing-shaped pectoral fins are key to their efficient and maneuverable swimming. The bionic manta ray, based on a biological manta ray prototype, mimics the motion characteristics of its pectoral fins, using a mechanical drive mechanism and flexible materials.

[0003] The pectoral fins of existing bionic manta ray robots are structurally simple and are usually only used to support and drive the reciprocating oscillation of the skin. In order to improve the movement flexibility and agility of the bionic manta ray robot, the traditional pectoral fin structure requires multiple driving fins to be arranged along the chord direction to increase the controllable degrees of freedom of the skin. At the same time, complex control algorithms are used to adjust the flapping amplitude, flapping frequency, flapping phase difference, flapping offset and other variables of each driving fin in real time, adjust the size and direction of the hydrodynamic force captured by the skin, making the robot system more complex and reducing the stability of the system operation.

[0004] Existing bionic manta ray robots have the problem of simple pectoral fin structure design and single function, which limits the flexibility and agility of the bionic manta ray robots. Summary of the Invention

[0005] In response to the above-mentioned defects or improvement needs of the prior art, the present invention provides a bionic manta ray robot with foldable fins and a control method thereof, which are used to solve the problems of the existing bionic manta ray robots, such as the simple pectoral fin structure design and single function, which limit the movement flexibility and agility of the bionic manta ray robot.

[0006] To achieve the above-mentioned objectives, according to one aspect of the present invention, a foldable fin bionic manta ray robot is provided, comprising a main frame, foldable fins respectively mounted on both sides of the main frame, and a flexible skin covering the foldable fins; the foldable fins comprise a flapping mechanism, a folding mechanism, and a driving mechanism, the flapping mechanism being rotatably connected to the main frame and configured to achieve up and down oscillation of the foldable fins by rotation, the folding mechanism being arranged on the flapping mechanism and configured as a retractable structure along the span direction of the flapping mechanism, the flexible skin being connected to the folding mechanism, the driving mechanism being mounted on the main frame and connected to the folding mechanism and configured to drive the folding mechanism to perform retractable movement along the span direction to achieve a change in the span length of the foldable fins.

[0007] According to the foldable fin bionic manta ray robot provided by the present invention, the flapping mechanism includes a flapping rod, a flapping seat and a flapping servo; the flapping seat is connected to the flapping rod at one end and is rotatably hinged to the main frame at the other end; the flapping servo is fixed to the main frame, connected to the flapping seat and drives the flapping seat to oscillate.

[0008] According to the foldable fin bionic manta ray robot provided by the present invention, the folding mechanism includes a plurality of folding units connected in sequence along the span direction, each of the folding units includes two groups of hinge chains correspondingly arranged on the upper and lower sides of the flapping mechanism and a rib support seat connected to the end of the hinge chain, each group of the hinge chains includes two rotatably connected connecting plates, and the opposite ends of the two connecting plates are respectively rotatably connected to the rib support seat, the corresponding ends of the two groups of hinge chains in each folding unit are connected to the same rib support seat, and one rib support seat is shared between two adjacent folding units.

[0009] According to the foldable fin bionic manta ray robot provided by the present invention, tooth structures are respectively provided at the opposite ends of the two connecting plates in each group of the hinge chains, and the tooth structures between two adjacent folding units are meshed and connected.

[0010] According to the foldable fin bionic manta ray robot provided by the present invention, the folding mechanism also includes a toothed side plate, which is connected to the side of the connecting plate, and one end of the toothed side plate is provided with teeth for forming the tooth structure.

[0011] According to the foldable fin bionic manta ray robot provided by the present invention, the driving mechanism includes a folding rope, an extension rope, a fin tip wire pulley and a winding servo; the winding servo is installed on the main frame, one end of the folding rope is wound around the winding servo, and the other end is connected to the folding mechanism, the fin tip wire pulley is arranged at the fin tip of the flapping mechanism, one end of the extension rope is wound around the winding servo, and the other end is connected to the folding mechanism after passing around the fin tip wire pulley.

[0012] According to the foldable fin bionic manta ray robot provided by the present invention, the winding directions of the folding rope and the stretching rope on the winding servo are opposite.

[0013] According to the foldable fin bionic manta ray robot provided by the present invention, the main frame includes a main bottom plate, a main top plate, support columns and floats; the main bottom plate and the main top plate are fixed together by support columns, and the floats are installed on the main top plate to provide buoyancy for the robot underwater.

[0014] The foldable fin bionic manta ray robot provided by the present invention also includes a tail fin and a main control board, wherein the tail fin includes a left tail fin plate, a left tail fin servo, a right tail fin plate, a right tail fin servo, and a tail fin fixing seat; the left tail fin plate is connected to the left tail fin servo and is controlled by the angle of the left tail fin servo; the right tail fin plate is connected to the right tail fin servo and is controlled by the angle of the right tail fin servo; the left tail fin servo and the right tail fin servo are mounted on the rear end of the main frame via the tail fin fixing seat;

[0015] The main control board is placed at the front end of the main frame and is connected to the foldable fin and the tail fin via signal lines.

[0016] According to another aspect of the present invention, a control method for a foldable fin bionic manta ray robot is provided. Based on any of the above-mentioned foldable fin bionic manta ray robots, the control method comprises:

[0017] During the downstroke and upstroke of a flapping cycle, the lengths of the foldable fins on both sides are controlled to remain constant, so that the robot moves forward horizontally.

[0018] The lengths of the foldable fins on both sides are increased simultaneously during a downstroke of a flapping cycle, and / or the lengths of the foldable fins on both sides are shortened simultaneously during an upstroke, so that the robot generates positive lift and causes an upward floating motion;

[0019] The lengths of the foldable fins on both sides are shortened simultaneously during a downstroke of a flapping cycle, and / or the lengths of the foldable fins on both sides are increased simultaneously during an upstroke, so that the robot generates negative lift and causes a diving action;

[0020] During the downstroke or upstroke of a flapping cycle, the length of the foldable fin on one side is increased and the length of the foldable fin on the other side is shortened, so that the robot obtains rolling and yaw moments.

[0021] In general, compared with the prior art, the above technical solutions conceived by the present invention provide a foldable fin bionic manta ray robot and a control method thereof:

[0022] 1. By providing a folding structure on the flapping mechanism to connect to the flexible skin, the folding structure, driven by a drive mechanism, causes the flexible skin to contract in the spanwise direction, thereby achieving changes in the spanwise length and projected area of ​​the foldable fin. This structurally expands the pectoral fin function of the bionic manta ray robot, thereby improving the manta ray robot's mobility and agility.

[0023] 2. It can mimic the changes in the projected area of ​​the pectoral fins of manta rays during various agile movements. Its design, assembly, and manufacturing are simple, enabling the agile movement of bionic manta ray robots to adapt to complex environments and diverse tasks using simple control algorithms.

[0024] 3. The bionic manta ray robot's pectoral fins are structurally adjustable in length. The length of the foldable fins can be varied in real time during flapping. By combining different fin lengths during the upstroke and downstroke of a flapping cycle, diverse dynamic performance can be achieved. Furthermore, the different lengths of the left and right foldable fins of the bionic manta ray robot also generate more driving torque in directions such as roll and yaw. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the three-dimensional structure of a bionic manta ray robot with foldable fins according to an embodiment of the present invention;

[0026] Figure 2 for Figure 1 Schematic diagram of the three-dimensional structure of the main frame and tail fin of the foldable fin bionic manta ray robot;

[0027] Figure 3 for Figure 1 A schematic diagram of the three-dimensional structure between the right foldable fin and the main base plate of the foldable fin bionic manta ray robot shown;

[0028] Figure 4 for Figure 3 A schematic diagram of the three-dimensional structure of the flapping mechanism in the foldable fin shown;

[0029] Figure 5 for Figure 3 A schematic diagram of the three-dimensional structure of the folding mechanism in the foldable fin shown;

[0030] Figure 6 for Figure 3 A schematic top view of the structure of the rope drive mechanism in the foldable fin shown;

[0031] Figure 7 for Figure 3 Side view comparison of the fully extended and fully folded states of the foldable fin shown;

[0032] Figure 8 for Figure 1 Schematic diagram showing the effect of different lengths of the foldable fin on the span change in the foldable fin bionic manta ray robot;

[0033] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0034] 1. Main frame; 2. Foldable fin; 3. Tail fin; 4. Flexible skin; 5. Main control panel; 1-1. Main bottom plate; 1-2. Main top plate; 1-3. Support column; 1-4. Float; 2-1. Flapping mechanism; 2-2. Folding mechanism; 2-3. Rope drive mechanism; 3-1. Left tail fin plate; 3-2. Left tail fin servo; 3-3. Right tail fin plate; 3-4. Right tail fin servo; 3-5. Tail fin fixing seat; 2-11. Flapping seat; 2-12. Flapping rod; 2-13. Flapping servo; 2-21. Connecting plate; 2-22. Toothed side plate; 2-23. Rib support seat; 2-24. Linear bearing; 2-31. Folding rope; 2-32. Extension rope; 2-33. Fin tip wire pulley; 2-34. Winding servo. DETAILED DESCRIPTION

[0035] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0036] See also Figure 1 , the present embodiment 1 provides a foldable fin bionic manta ray robot, which includes a main frame 1, foldable fins 2 respectively installed on both sides of the main frame 1, and a flexible skin 4 covering the foldable fins 2; the foldable fins 2 include a flapping mechanism 2-1, a folding mechanism 2-2 and a driving mechanism, the flapping mechanism 2-1 is rotatably connected to the main frame 1, and is used to realize the up and down oscillation of the foldable fin 2 by rotation, the folding mechanism 2-2 is provided on the flapping mechanism 2-1 and is set as a retractable structure along the span direction of the flapping mechanism 2-1, the flexible skin 4 is connected to the folding mechanism 2-2, the driving mechanism is installed on the main frame 1 and is connected to the folding mechanism 2-2, and is used to drive the folding mechanism 2-2 to move telescopically along the span direction to realize the length change of the foldable fin 2.

[0037] In this embodiment, the main frame 1 serves as the main structure connecting the remaining components; there are two foldable fins 2, which are respectively installed on the left and right sides of the main frame 1, covered by a flexible skin 4, and composed of a flapping mechanism 2-1, a folding mechanism 2-2 and a driving mechanism; the foldable fins 2 are driven by the flapping mechanism 2-1 to oscillate up and down, driving the flexible skin 4 covering it to interact with the water flow, capture water power, and provide a power source for the robot.

[0038] This embodiment takes into account that in nature, manta rays adjust the magnitude and direction of the hydrodynamic forces they capture by changing the projected area of ​​their pectoral fins during movement, enabling them to perform a variety of agile swimming maneuvers. However, existing bionic manta ray robots are generally unable to structurally change the projected area of ​​their pectoral fins. Based on this, this embodiment proposes a bionic manta ray robot with foldable fins. By structurally varying the size of the pectoral fins in the span direction, this can simulate the changes in projected area of ​​the manta ray's pectoral fins during different swimming maneuvers. This allows for the robot to achieve dexterous movement and improve its agility through simple structural assembly and control algorithms.

[0039] In some specific embodiments, reference Figure 3 and Figure 4 The flapping mechanism 2-1 includes a flapping rod 2-12, a flapping seat 2-11, and a flapping servo 2-13. The flapping seat 2-11 is connected to the flapping rod 2-12 at one end and is rotatably hinged to the main frame 1 at the other end, so that the flapping seat 2-11 and the flapping rod 2-12 can rotate relative to the main frame 1 as a whole to achieve up and down oscillation. The flapping servo 2-13 is fixed to the main frame 1, connected to the flapping seat 2-11, and drives the flapping seat 2-11 to oscillate. A side plate can be provided on the main frame 1, and the flapping seat 2-11 can be rotatably connected to the side plate at the other end via a rotating bearing. The output shaft of the flapping servo 2-13 can be transmission-connected to the other end of the flapping seat 2-11, thereby driving the flapping seat 2-11 and the flapping rod 2-12 to rotate.

[0040] In some specific embodiments, the folding mechanism 2-2 includes a plurality of folding units connected in sequence along the span direction, each of the folding units includes two groups of hinge chains correspondingly arranged on the upper and lower sides of the flapping mechanism 2-1 and a rib support seat 2-23 connected to the end of the hinge chain, each group of the hinge chains includes two rotatably connected connecting plates 2-21, and the opposite ends of the two connecting plates 2-21 are respectively rotatably connected to the rib support seat 2-23, the corresponding ends of the two groups of hinge chains in each folding unit are connected to the same rib support seat 2-23, and one rib support seat 2-23 is shared between two adjacent folding units.

[0041] In some specific embodiments, two connecting plates 2-21 in each set of the hinged chains are provided with tooth structures at opposite ends thereof, and the tooth structures between two adjacent folding units are meshed and connected.

[0042] In some specific embodiments, the folding mechanism 2-2 also includes a toothed side plate 2-22, which is connected to the side of the connecting plate 2-21, and one end of the toothed side plate 2-22 is provided with teeth for forming the tooth structure.

[0043] refer to Figure 3 and Figure 5 In this embodiment, the folding mechanism 2-2 includes a connecting plate 2-21, a toothed side plate 2-22, a rib support seat 2-23 and a linear bearing 2-24; the rib support seat 2-23 and the flapping rod 2-12 are coaxially constrained by the linear bearing 2-24 and can slide on the flapping rod 2-12; each connecting plate 2-21 is connected to a toothed side plate 2-22 on both sides. The two connecting plates 2-21 are hinged together to form a set of hinge chains, and one end of the two corresponding sets of hinge chains is installed on the upper and lower sides of the rib support seat 2-23 to form a folding unit. Multiple folding units are chain-connected to the flapping mechanism 2-1, and the toothed side plates 2-22 on adjacent folding units are engaged with each other to achieve coupling and linkage of multiple folding units.

[0044] In this embodiment, one end of two corresponding upper and lower hinge chains and a rib support base 2-23 are rotatably connected together via pins to form a foldable unit. When the other ends of the two hinge chains are connected to the rib support bases 2-23 of other foldable units, multiple foldable units can be chained together in this manner. The toothed side plates 2-22 of the chained foldable units engage with each other, coupling the sliding freedom of the multiple foldable units together. The end of the hinge chain closest to the fin root, i.e., the end closest to the main frame 1, near the fin root, can be directly rotatably connected to the flapping base 2-11.

[0045] The number and size of the folding units used on each foldable fin 2 can be adjusted according to the size and telescopic length requirements of the robot, and the embodiment of the present invention does not impose any unique limitation.

[0046] In some specific embodiments, reference Figure 6 The driving mechanism includes a folding rope 2-31, an extension rope 2-32, a fin tip wire pulley 2-33, and a winding servo 2-34. The winding servo 2-34 is mounted on the main frame 1. One end of the folding rope 2-31 is wound around the winding servo 2-34 and the other end is connected to the folding mechanism 2-2. The fin tip wire pulley 2-33 is located at the fin tip of the flapping mechanism 2-1. One end of the extension rope 2-32 is wound around the winding servo 2-34 and the other end is connected to the folding mechanism 2-2 after passing through the fin tip wire pulley 2-33. The winding servo 2-34 drives the folding rope 2-31 and the extension rope 2-32 to move.

[0047] In some specific embodiments, one end of the folding rope 2-31 is connected to the winding servo 2-34, and the other end is fixed to the rib support seat 2-23 closest to the root of the fin; the extension rope 2-32 is led out from the winding servo 2-34 and passed around the fin tip wire wheel 2-33 and then fixed to the rib support seat 2-23 closest to the root of the fin.

[0048] In some specific embodiments, the folding rope 2-31 and the stretching rope 2-32 are wound in opposite directions on the winding servo 2-34.

[0049] refer to Figure 6 The winding servo 2-34 is fixed on the main base plate 1-1 of the main frame 1, and winds the folding rope 2-31 and the stretching rope 2-32 in clockwise and counterclockwise directions respectively; the folding rope 2-31 is directly fixed on the rib support seat 2-23 closest to the root of the fin; the stretching rope 2-32 passes around the fin tip wire wheel 2-33 and is fixed on the rib support seat 2-23 closest to the root of the fin, forming a belt transmission form with the folding rope 2-31.

[0050] When the winding servo 2-34 rotates counterclockwise, the folding rope 2-31 is tightened and the extension rope 2-32 is relaxed, driving the multiple folding units to slide inward synchronously, reducing the length of the foldable fin 2. When the winding servo 2-34 rotates clockwise, it pulls the extension rope 2-32, causing the folding rope 2-31 to relax, driving the multiple folding units to slide outward, increasing the length of the foldable fin 2. Specifically, the folding rope 2-31 will pull the folding unit closest to the fin root to slide inward, while the remaining folding units connected in series will move together under the drive of the toothed side plate 2-22. The extension rope 2-32 is tightened and drives the folding unit closest to the fin root to slide outward, while the remaining folding units connected in series will slide outward synchronously under the drive of the toothed side plate 2-22.

[0051] The clockwise and counterclockwise directions in this embodiment are described for the purpose of illustrating the motion principle more clearly, without making any unique limitation. Figure 7 The structural positions of the foldable fin 2 at the longest length and the shortest length are shown in the figure.

[0052] In some specific embodiments, the main frame 1 includes a main bottom plate 1-1, a main top plate 1-2, support columns 1-3 and floats 1-4; the main bottom plate 1-1 and the main top plate 1-2 are fixed together through the support columns 1-3, and the floats 1-4 are installed on the main top plate 1-2 to provide buoyancy for the robot underwater. Figure 2 The main bottom plate 1-1 serves as the main load-bearing component to which the remaining components are fixed, and is fixed to the main top plate 1-2 by supporting it; the floating block 1-4 is fixed on the main top plate 1-2 to provide buoyancy for the robot underwater and balance the gravity of the robot underwater.

[0053] Among them, the support columns 1-3 are used to support the main top plate 1-2, and the floating blocks 1-4 are used to balance gravity. Therefore, their number needs to be adjusted according to the size and weight of the robot, and the embodiment of the present invention does not make any unique limitation.

[0054] In this embodiment, the foldable fin 2 includes a flapping mechanism 2-1, a folding mechanism 2-2 and a driving mechanism; the flapping mechanism 2-1 is installed on the main base plate 1-1 and can rotate relative to the main base plate 1-1, driving the entire foldable fin 2 to oscillate back and forth up and down; the folding mechanism 2-2 is mounted on the flapping mechanism 2-1, can move up and down with the flapping mechanism 2-1, and can slide along the axis of the flapping mechanism 2-1; the rope driving mechanism 2-3 is fixed on the main base plate 1-1 and is connected to the folding mechanism 2-2 by two sets of ropes.

[0055] In some specific embodiments, reference Figure 2 A bionic manta ray robot with a foldable fin 2 also includes a tail fin 3 and a main control board 5, wherein the tail fin 3 includes a left tail fin plate 3-1, a left tail fin servo 3-2, a right tail fin plate 3-3, a right tail fin servo 3-4 and a tail fin fixing seat 3-5; the left tail fin plate 3-1 is connected to the left tail fin servo 3-2 and is controlled by the angle of the left tail fin servo 3-2; the right tail fin plate 3-3 is connected to the right tail fin servo 3-4 and is controlled by the angle of the right tail fin servo 3-4; the left tail fin servo 3-2 and the right tail fin servo 3-4 are installed at the rear end of the main frame 1 through the tail fin fixing seat 3-5;

[0056] The main control board 5 is placed at the front end of the main frame 1 and is connected to the foldable fin 2 and the tail fin 3 via signal lines.

[0057] The tail fin 3 is mounted at the rear of the main frame 1. The main control board 5 is placed at the front of the main frame 1 and is connected to the foldable fin 2 and the tail fin 3 via signal cables. In this embodiment, the angles of the left and right tail fins 3-1 and 3-3 can be adjusted in real time during the robot's swimming, assisting in adjusting the robot's roll, yaw, and pitch angles.

[0058] Further, refer to Figure 1 and Figure 3 The folding mechanism can be connected to a support rod for connecting and fixing the flexible skin by bonding or other means. Specifically, the support rod can be connected to the rib support seat. Figure 5 and Figure 6 Rib plates can be set on both sides of the rib support seat, and the rib plates are provided with openings, which can be used to pass through or fix ropes.

[0059] The foldable fin 2 can change its length in real time during the oscillation process, thereby adjusting the hydrodynamic performance of the robot during flapping and making various agile movements. Figure 8 During movement, the Foldable Fin 2 bionic manta ray robot can adjust the length of each wing in real time, thereby producing changes in span and obtaining more diverse dynamic performance.

[0060] Furthermore, this second embodiment provides a control method for a foldable fin bionic manta ray robot. Based on any of the above-mentioned foldable fin bionic manta ray robots, the control method includes:

[0061] During the downstroke and upstroke of a flapping cycle, the lengths of the foldable fins 2 on both sides are controlled to remain unchanged, so that the robot moves forward horizontally;

[0062] In a downstroke of a flapping cycle, the lengths of the foldable fins 2 on both sides are increased simultaneously, and / or, in an upstroke, the lengths of the foldable fins 2 on both sides are shortened simultaneously, so that the robot generates positive lift to cause an upward floating motion;

[0063] The lengths of the foldable fins 2 on both sides are shortened simultaneously during the downstroke of a flapping cycle, and / or the lengths of the foldable fins 2 on both sides are increased simultaneously during the upstroke, so that the robot generates negative lift and causes a diving action;

[0064] In a downstroke or upstroke of a flapping cycle, the length of the foldable fin 2 on one side is increased and the length of the foldable fin 2 on the other side is shortened, so that the robot obtains rolling and yaw moments.

[0065] In this embodiment, a flapping cycle is divided into a downstroke and an upstroke; when the lengths of the fins on both sides remain unchanged during the downstroke and upstroke, the robot will maintain a steady horizontal forward motion; when the lengths of the left and right fins are increased at the same time during the downstroke, and when the lengths of the left and right fins are shortened at the same time during the upstroke, the robot will generate a significant positive lift to cause an upward floating action; when the lengths of the left and right fins are shortened at the same time during the downstroke and the lengths of the left and right fins are increased at the same time during the upstroke, the robot will generate a significant negative lift to cause a diving action; when the length of the left fin is increased and the length of the right fin is shortened during the downstroke, the robot will obtain a rolling and yaw moment; the above examples illustrate how the length adjustment of the foldable fin 2 can achieve and improve the agility of the bionic manta ray robot under simple control.

[0066] The foldable fin bionic manta ray robot provided by the present invention comprises a main frame 1 as the main structure connecting the remaining components. The foldable fins 2 are fixed to the left and right sides of the main frame 1 and consist of a flapping mechanism 2-1, a folding mechanism 2-2, and a rope drive mechanism 2-3. The flapping mechanism 2-1 drives the foldable fins 2 to oscillate up and down. The folding mechanism 2-2 can expand and fold along the robot's span, changing the robot's span in real time during the oscillation. The rope drive mechanism 2-3 is fixed to the main frame 1 and moves the folding mechanism 2-2 by pulling it with two sets of flexible ropes. A flexible skin 4 covers the foldable fins 2 to capture hydrodynamic forces during flapping. A tail fin 3 is mounted behind the main frame 1 to assist in posture adjustment. A main control board 5 is connected to each mechanism via signal lines to control its movement. The present invention structurally mimics the changes in the projected area of ​​the pectoral fins of manta rays during various agile movements, facilitating the agile movement of the bionic manta ray robot using a simple control algorithm.

[0067] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A bionic manta ray robot with foldable fins, characterized in that: The invention comprises a main frame, foldable fins respectively installed on both sides of the main frame, and a flexible skin covering the foldable fins; the foldable fins include a flapping mechanism, a folding mechanism and a driving mechanism, the flapping mechanism being rotatably connected to the main frame and being used to realize the up and down oscillation of the foldable fins by rotation, the folding mechanism being arranged on the flapping mechanism and being set as a retractable structure along the span direction of the flapping mechanism, the flexible skin being connected to the folding mechanism, the driving mechanism being installed on the main frame and connected to the folding mechanism and being used to drive the folding mechanism to perform retractable movement along the span direction to realize the length change of the foldable fins.

2. The foldable fin bionic manta ray robot according to claim 1, characterized in that: The flapping mechanism includes a flapping rod, a flapping seat and a flapping servo; the flapping seat is connected to the flapping rod at one end and is rotatably hinged to the main frame at the other end; the flapping servo is fixed on the main frame, connected to the flapping seat and drives the flapping seat to oscillate.

3. The foldable fin bionic manta ray robot according to claim 1, characterized in that: The folding mechanism includes a plurality of folding units connected in sequence along the span direction, each of the folding units includes two groups of hinge chains correspondingly arranged on the upper and lower sides of the flapping mechanism and a rib support seat connected to the end of the hinge chain, each group of the hinge chains includes two connecting plates connected in rotation, and the opposite ends of the two connecting plates are respectively connected in rotation to the rib support seat, the corresponding ends of the two groups of hinge chains in each folding unit are connected to the same rib support seat, and one rib support seat is shared between two adjacent folding units.

4. The foldable fin bionic manta ray robot according to claim 3, characterized in that: The two connecting plates in each set of the hinged chains are provided with tooth structures at the two opposite ends thereof, and the tooth structures between two adjacent folding units are meshed and connected.

5. The foldable fin bionic manta ray robot according to claim 4, characterized in that: The folding mechanism further includes a toothed side plate, which is connected to the side of the connecting plate. One end of the toothed side plate is provided with teeth for forming the tooth structure.

6. The foldable fin bionic manta ray robot according to any one of claims 1 to 5, characterized in that: The driving mechanism includes a folding rope, an extension rope, a fin tip wire pulley and a winding servo; the winding servo is installed on the main frame, one end of the folding rope is wound around the winding servo, and the other end is connected to the folding mechanism, the fin tip wire pulley is arranged at the fin tip of the flapping mechanism, one end of the extension rope is wound around the winding servo, and the other end is connected to the folding mechanism after passing around the fin tip wire pulley.

7. The foldable fin bionic manta ray robot according to claim 6, characterized in that: The winding directions of the folding rope and the stretching rope on the winding servo are opposite.

8. The foldable fin bionic manta ray robot according to any one of claims 1 to 5, characterized in that: The main frame includes a main bottom plate, a main top plate, support columns and floating blocks; the main bottom plate and the main top plate are fixed together through support columns, and the floating blocks are installed on the main top plate to provide buoyancy for the robot underwater.

9. The foldable fin bionic manta ray robot according to any one of claims 1 to 5, characterized in that: The main body frame further includes a tail fin and a main control panel, wherein the tail fin includes a left tail fin plate, a left tail fin servo, a right tail fin plate, a right tail fin servo, and a tail fin fixing seat; the left tail fin plate is connected to the left tail fin servo and is controlled by the angle of the left tail fin servo; the right tail fin plate is connected to the right tail fin servo and is controlled by the angle of the right tail fin servo; the left tail fin servo and the right tail fin servo are mounted on the rear end of the main body frame via the tail fin fixing seat; The main control board is placed at the front end of the main frame and is connected to the foldable fin and the tail fin via signal lines.

10. A control method for a bionic manta ray robot with foldable fins, characterized in that: Based on the foldable fin bionic manta ray robot according to any one of claims 1 to 9, the control method includes: During the downstroke and upstroke of a flapping cycle, the lengths of the foldable fins on both sides are controlled to remain constant, so that the robot moves forward horizontally. The lengths of the foldable fins on both sides are increased simultaneously during a downstroke of a flapping cycle, and / or the lengths of the foldable fins on both sides are shortened simultaneously during an upstroke, so that the robot generates positive lift and causes an upward floating motion; The lengths of the foldable fins on both sides are shortened simultaneously during a downstroke of a flapping cycle, and / or the lengths of the foldable fins on both sides are increased simultaneously during an upstroke, so that the robot generates negative lift and causes a diving action; During the downstroke or upstroke of a flapping cycle, the length of the foldable fin on one side is increased and the length of the foldable fin on the other side is shortened, so that the robot obtains rolling and yaw moments.

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