Self-powered underwater bionic robot driven by shape memory alloy

Abstract

This invention provides a shape memory alloy-driven self-powered underwater biomimetic robot, comprising a pectoral fin undulation mechanism, a pectoral fin folding and unfolding mechanism, a fuselage, a wave energy conversion device, a center of gravity adjustment device, a battery, and a control module. The pectoral fin undulation mechanism and the pectoral fin folding and unfolding mechanism form a foldable pectoral fin, which is hinged to the fuselage via a pectoral fin rotation axis. In the unfolded state, the foldable pectoral fin captures wave energy to drive the wave energy conversion device to generate electricity and charge the battery. In the folded state, the pectoral fin undulation mechanism generates a sinusoidal propulsion wave. The control module, wave energy conversion device, and center of gravity adjustment device are all installed within the fuselage. The control module controls the movement of the foldable pectoral fin. This invention utilizes a shape memory alloy to design a novel flexible drive mechanism, reducing the weight and volume of the drive mechanism, solving the problems of traditional solutions, and achieving biomimetic goals.

Description

Technical Field

[0001] The present invention relates to, in particular, a self-powered underwater bionic robot driven by a shape memory alloy. Background Art

[0002] Most existing underwater bionic robots use electric motors as their driving source, which have disadvantages such as large size and weight, and high energy consumption, making it difficult to meet the requirements of the structural size and endurance of micro-robots.

[0003] Patent CN113320665A proposes a long-fin wave-propelled underwater robot, which uses a servo-driven series four-bar linkage to achieve high-frequency continuous fluctuations on the fin surface. It has good maneuverability and anti-interference capabilities. The robot is powered by a 2200mAh lithium battery, which can only support the robot to move at a speed of 0.2m / s for more than 2 hours. Patent CN108528666B discloses a bionic manta ray underwater robot, which consists of a main frame, a battery, a control module, a water pump, a tail assembly and multiple pairs of wave rods, wherein a motor controls a differential wave mechanism to move the structure, a battery is used to provide energy for the movement of the robot, and a water storage tank and a water pump are used to achieve sinking and floating movements. The underwater bionic robots disclosed in the above patents have a short battery life, and their battery life is limited by the capacity of the onboard lithium battery. When used in ocean exploration missions, they need to be frequently recovered and deployed.

[0004] Patent CN113548146A discloses a self-powered underwater robot based on tidal energy, including a first cabin, a second cabin, an impeller and a power generation mechanism. The impeller is used to drive the generator to generate electricity. This solution can control the extension and storage of the impeller, realize the utilization of tidal energy, and will not affect the navigation of the AUV. However, it has the disadvantages of poor motion performance and great interference to the environment. Summary of the invention

[0005] In view of the defects in the prior art, the object of the present invention is to provide a self-powered underwater bionic robot driven by a shape memory alloy.

[0006] A shape memory alloy driven self-powered underwater bionic robot provided by the present invention comprises a pectoral fin wave mechanism, a pectoral fin folding and unfolding mechanism, a fuselage, a wave energy conversion device, a center of gravity adjustment device, a battery and a control module, wherein:

[0007] The pectoral fin undulating mechanism and the pectoral fin folding mechanism form a foldable pectoral fin, and the foldable pectoral fin is hinged to the fuselage through a pectoral fin rotation axis;

[0008] When the foldable pectoral fins are in the unfolded state, they capture wave energy to drive the wave energy conversion device to generate electricity and charge the battery; when in the folded state, the pectoral fin wave mechanism generates a quasi-sine propulsion wave;

[0009] The control module, the wave energy conversion device, and the center of gravity adjustment device are all installed in the fuselage cabin;

[0010] The control module controls the movement of the foldable pectoral fin.

[0011] Preferably, the pectoral fin undulation mechanism comprises a membrane, a fin swing unit, an undulation cabin, a pectoral fin undulation cabin cover, a positive electrode assembly, a negative electrode assembly, and a shaft end cover, wherein:

[0012] The wave cabin body and the pectoral fin wave cabin cover are connected by bolts, and a sealing gasket is installed between the two;

[0013] There are multiple groups of fin ray swinging units, and the multiple groups of fin ray swinging units are covered with thin films, so that the multiple groups of fin rays can swing alternately;

[0014] The positive electrode assembly and the negative electrode assembly are assembled in the toggle cabin.

[0015] Preferably, the fin swing unit comprises a carbon fiber rod, a fin connector, a first one-way shape memory alloy wire, a second one-way shape memory alloy wire, a fin swing shaft, a sleeve, a flange bearing, a first sealing ring, and a second sealing ring, wherein:

[0016] The carbon fiber rod is bonded to the fin ray connecting member, and the fin ray connecting member is connected to the fin ray swing axis via a pin;

[0017] The sleeve presses the flange bearing onto one side of the first sealing ring, the other side of the first sealing ring is pressed against the wave chamber, and the second sealing ring is installed in the shaft hole of the wave chamber;

[0018] Each group of fin swing units is axially positioned by an insulating pad;

[0019] One side of the first one-way shape memory alloy wire and the second one-way shape memory alloy wire is wound around the positive electrode assembly, passes through the small hole of the fin swing axis in the opposite direction, and the other side is wound around the negative electrode assembly.

[0020] Preferably, the positive electrode assembly comprises a first positive electrode, a second positive electrode and an insulating connector, wherein:

[0021] One side of the first one-way shape memory alloy wire is wound around the first positive electrode, and one side of the second one-way shape memory alloy wire is wound around the second positive electrode;

[0022] Each group of positive electrodes is connected via the insulating connector 164 .

[0023] Preferably, the negative electrode assembly comprises a negative electrode and an insulating connector, and each group of negative electrodes is connected via the insulating connector.

[0024] Preferably, the pectoral fin folding and unfolding mechanism comprises a pectoral fin bracket, a lead screw, a polished rod, a lead screw flange, a first scissor-type connecting rod group, a second scissor-type connecting rod group and a micro reduction motor, wherein:

[0025] The lead screw, polished rod and micro reduction motor are all arranged on the pectoral fin bracket;

[0026] The pectoral fin folding and unfolding mechanism is connected to the undulating cabin of the pectoral fin undulating mechanism via a scissor-type connecting rod group;

[0027] One of the connecting rods of the first scissor-type connecting rod group is connected to a screw flange arranged on the screw;

[0028] The micro reduction motor drives the first scissor-type connecting rod group to move under the limit of the lead screw;

[0029] The second scissor-type connecting rod group is arranged on the polished rod, and when the first scissor-type connecting rod group moves, it drives the second scissor-type connecting rod group to move under the limit of the polished rod.

[0030] Preferably, the first scissor-type connecting rod assembly comprises a flange connector, a first connecting rod, a plug bolt, a bearing, a second connecting rod, a first polished rod slider and a first polished rod, wherein:

[0031] The flange connector is connected to the screw flange via bolts;

[0032] One side of the first connecting rod is hingedly connected to the pectoral fin bracket by a plug bolt, and the other side is connected to the first polished rod slider;

[0033] The bearing is mounted on the first connecting rod and the second connecting rod and connected by plug bolts;

[0034] One side of the second connecting rod is connected to the flange connector, and the other side is hingedly connected to the wave cabin through a plug bolt;

[0035] The first polished rod slider is sleeved on the first polished rod to form a cylindrical pair, and the first connecting rod limits the rotational freedom and slides linearly along the first polished rod.

[0036] Preferably, the wave energy conversion device comprises a two-stage gear speed increasing mechanism, a generator, a piezoelectric vibrator and a piezoelectric paddle shaft, wherein:

[0037] The foldable pectoral fin is hinged to the fuselage through the pectoral fin rotation axis;

[0038] One side of the pectoral fin rotation axis is connected to the pectoral fin bracket of the foldable pectoral fin, and the other side is connected to the input gear of the secondary gear speed increasing mechanism;

[0039] The output gear of the secondary gear speed increasing mechanism is connected to the generator;

[0040] The generator and the piezoelectric vibrator are directly mounted on a support below the fuselage cabin.

[0041] Preferably, the piezoelectric vibrator comprises piezoelectric ceramics and a copper sheet, the piezoelectric ceramics are mounted on the copper sheet, and shear grooves are alternately formed on the copper sheet.

[0042] Preferably, the center of gravity adjustment device includes a stepper motor, a motor bracket, a screw, a battery, a screw flange, a weight holder upper cover, a weight holder, and an optical axis, wherein:

[0043] The stepper motor is mounted on the motor bracket, and the motor bracket is mounted on a support below the fuselage cabin;

[0044] One side of the screw rod is connected to the stepping motor via a thread, and the other side is directly stuck in the U-shaped groove reserved at the rear of the fuselage cabin;

[0045] The battery is used as a weight of the center of gravity adjustment device, and is pressed tightly into two grooves of the weight holder by the upper cover of the weight holder, and the weight holder is connected to the screw flange;

[0046] The optical axis passes through two circular holes below the weight retaining frame, and the front and rear sides of the optical axis are clamped in U-shaped grooves reserved at the front and rear of the fuselage cabin.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. The present invention adopts shape memory alloy to design a new type of flexible driving mechanism, which reduces the weight and volume of the driving mechanism, solves the problems existing in traditional solutions, and achieves the purpose of bionics.

[0049] 2. The foldable pectoral fins designed in the present invention enable the robot to have two working modes: the pectoral fins are folded during movement and unfolded during energy capture, thereby resolving the contradiction between the opposite requirements on the size of the robot's pectoral fins for efficient movement of the robot and raft-type wave energy generation, and utilizing wave energy to improve the robot's endurance. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0051] Figure 1 Schematic diagram of the self-powered underwater bionic robot in the energy harvesting state.

[0052] Figure 2 Schematic diagram of the self-powered underwater bionic robot in motion.

[0053] Figure 3Schematic diagram of the extended state of the foldable pectoral fins of the self-powered underwater bionic robot.

[0054] Figure 4 Schematic diagram of the folded state of the foldable pectoral fins of the self-powered underwater bionic robot.

[0055] Figure 5 It is a partial cross-sectional view of the shaft system of the pectoral fin undulating mechanism.

[0056] Figure 6 Schematic diagram of the winding of shape memory alloy wire for the fin swing unit.

[0057] Figure 7 Schematic diagram of the electrode assembly of the pectoral fin undulation mechanism.

[0058] Figure 8 Schematic diagram of the internal structure of the self-powered underwater bionic robot.

[0059] Fig. 9 Schematic diagram of the center of gravity adjustment mechanism. DETAILED DESCRIPTION

[0060] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0061] As shown in the picture Fig. 9 As shown, an underwater bionic robot provided according to the present invention includes a pectoral fin wave mechanism 1, a pectoral fin folding and unfolding mechanism 2, a fuselage 3, a wave energy conversion device 4, a center of gravity adjustment device 5, and a control module 6, wherein the fuselage 3 includes a fuselage top cover 31, a sealing pad 32 and a fuselage cabin 33.

[0062] The pectoral fin undulating mechanism 1 and the pectoral fin folding mechanism 2 constitute the foldable pectoral fin of the robot. The foldable pectoral fin is hinged to the fuselage 3 via the pectoral fin rotating shaft 28. The foldable pectoral fin of the underwater robot has two states: folded and unfolded. In the unfolded state, the robot uses the foldable pectoral fin to capture wave energy to drive the wave energy conversion device 4 to generate electricity and charge the battery 54. In the folded state, the pectoral fin undulating mechanism 1 generates a quasi-sinusoidal propulsion wave to achieve basic movement.

[0063] The control module 6 is installed at the front of the underwater robot body cabin 33 , the wave energy conversion device 4 and the center of gravity adjustment device 5 are installed at the middle and rear part of the fuselage cabin 33 , and the center of gravity adjustment device 5 is located above the wave energy conversion device 4 .

[0064] The pectoral fin wave mechanism 1 includes a membrane 11, a fin swing unit 12, a wave chamber 13, a sealing gasket 14, a pectoral fin wave chamber cover 15, a positive electrode assembly 16, a negative electrode assembly 17, a shaft end cover 18, and an insulating gasket 19. The wave chamber 13 and the pectoral fin wave chamber cover 15 are connected by bolts, and a sealing gasket 14 is installed between the two to achieve sealing and waterproofing.

[0065] The pectoral fin oscillation mechanism includes 5 groups of fin ray oscillation units 12, and the 5 groups of fin ray oscillation units are covered with a film 11 to simulate the flexible oscillation characteristics of the pectoral fins of rays. The basic movement of the robot is achieved by generating a quasi-sine propulsion wave through the alternating oscillation of each group of fin rays.

[0066] The fin swing unit 12 includes a carbon fiber rod 121, a fin connector 122, a first one-way shape memory alloy wire 123, a second one-way shape memory alloy wire 124, a pin 125, a fin swing shaft 126, a sleeve 127, a flange bearing 128, a first sealing ring 129, and a second sealing ring 1210.

[0067] The carbon fiber rod 121 is bonded to the fin ray connector 122 , and the fin ray connector 122 is connected to the fin ray swing shaft 126 via the pin 125 .

[0068] The shaft system axial positioning method of the fin swing unit 12 is as follows: the sleeve 127 presses the flange bearing 128 on one side of the first sealing ring 129, the other side of the sealing ring 139 is pressed against the wave chamber 13, and the second sealing ring 1210 is installed in the shaft hole of the wave chamber 13. Each group of fin swing units is axially positioned by an insulating pad 19.

[0069] The fin swing unit 12 realizes waterproof sealing of the shaft system through the first sealing ring 129 and the second sealing ring 1210.

[0070] The positive electrode assembly 16 includes a positive electrode end cap 161 , a first positive electrode 162 , a second positive electrode 163 , and an insulating connector 164 , and each group of positive electrodes is connected via the insulating connector 164 .

[0071] The negative electrode assembly 17 includes a negative electrode end cap 171 , a negative electrode 172 , and an insulating connector 173 , and each group of negative electrodes is connected via the insulating connector 173 .

[0072] One side of the first one-way shape memory alloy wire 123 is wound around the first positive electrode 162, passes through the small hole on the fin swing shaft 126 from right to left, and the other side is wound around the negative electrode 172. One side of the second one-way shape memory alloy wire 124 is wound around the second positive electrode 163, passes through another small hole on the fin swing shaft 126 from left to right, and the other side is wound around the negative electrode 172. It is worth noting that the directions in which the two one-way shape memory alloy wires pass through the fin swing shaft 126 should be opposite to ensure the repeated pulling effect of the shape memory alloy wire on the fin swing shaft when alternating power is applied.

[0073] The working principle of the fin swing unit 12 is as follows: when the first one-way shape memory alloy wire 123 is powered on, the first one-way shape memory alloy wire 123 contracts and pulls the fin swing shaft 126 to rotate counterclockwise, and the carbon fiber rod 121 swings upward. The counterclockwise rotation of the fin swing shaft 126 will simultaneously pull the second one-way shape memory alloy wire 124 to cause it to be stretched and deformed. After the first one-way shape memory alloy wire 123 is powered off, the fin swing shaft 126 rotates clockwise under the action of the tensile stress inside the second one-way shape memory alloy wire 124, and the carbon fiber rod 121 swings upward. The rod 121 returns to its original position; when the second one-way shape memory alloy wire 124 is energized, the second one-way shape memory alloy wire 124 contracts and pulls the fin swing shaft 126 to rotate clockwise, and the carbon fiber rod 121 swings downward. The clockwise rotation of the fin swing shaft 126 pulls the first one-way shape memory alloy wire 123, causing it to be stretched and deformed. After the second one-way shape memory alloy wire 124 is powered off, the fin swing shaft 126 rotates counterclockwise under the tensile stress inside the first one-way shape memory alloy, and the carbon fiber rod 121 returns to its original position. The first one-way shape memory alloy wire 123 and the second one-way shape memory alloy wire 124 are alternately energized, and the fin swing unit 12 will produce reciprocating swings.

[0074] Compared with the current mainstream motor-driven rigid solution, the fin swing unit 12 is small in size, light in weight, simple and compact in structure, and has a certain degree of flexibility. It is closer to the movement mode driven by muscles of organisms, which is conducive to the bionic and lightweight robot.

[0075] The working principle of the pectoral fin waving mechanism 1 is as follows: by controlling the power-on time and power-on voltage of the one-way shape memory alloy wires in the five groups of fin ray swing units 12, the swing amplitude, response speed and swing phase difference of different fin ray swing units are adjusted, so that the pectoral fin waving mechanism generates a sine-like propulsion wave, thereby realizing the basic movement of the underwater robot.

[0076] The pectoral fin folding and unfolding mechanism 2 comprises a pectoral fin bracket 21, a screw rod 22, a polished rod 23, a screw rod flange 24, a first scissor-type connecting rod group 25, a second scissor-type connecting rod group 26, a micro reduction motor 27, a pectoral fin rotating shaft 28, and a motor cabin cover 29. The pectoral fin folding and unfolding mechanism is connected to the undulating cabin of the pectoral fin undulating mechanism through the scissor-type connecting rod group.

[0077] More specifically, the first scissor-type connecting rod assembly includes a flange connector 251 , a first connecting rod 252 , a driving bolt 253 , a bearing 254 , a second connecting rod 255 , a first smooth rod slider 256 , a first smooth rod 257 , a driving bolt 258 , and a driving bolt 259 .

[0078] The flange connector 251 is connected to the screw flange 24 via bolts, so as to convert the rotational motion of the screw 22 into the linear motion of the driving member of the first scissor-type linkage mechanism 25 .

[0079] One side of the first connecting rod 252 is hingedly connected to the pectoral fin bracket 21 via a plug bolt 259 , and the other side is connected to the first bare rod slider 256 .

[0080] The bearing 254 is installed on the first connecting rod 252 and the second connecting rod 255 and connected by a plug bolt 253.

[0081] One side of the second connecting rod 255 is connected to the flange connector 251 , and the other side is hingedly connected to the wave cabin 13 via a plug bolt 258 .

[0082] The first polished rod slider 256 is loosely sleeved on the first polished rod 257 to form a cylindrical pair, and the first connecting rod 252 limits the rotational freedom and can only slide linearly along the first polished rod 257.

[0083] The second scissor-type connecting rod assembly 26 includes a polished rod slider 261 , a third connecting rod 262 , a plug bolt 263 , a bearing 264 , a fourth connecting rod 265 , a second polished rod slider 266 , a second polished rod 267 , a plug bolt 268 , and a plug bolt 269 .

[0084] The polished rod slider 261 is loosely sleeved on the polished rod 23 to form a cylindrical pair, and the rotational freedom is limited by the fourth connecting rod 265, so that it can only slide linearly along the polished rod 23.

[0085] One side of the third connecting rod 262 is hingedly connected to the pectoral fin bracket 21 via a plug bolt 269 , and the other side is connected to the second bare rod slider 266 .

[0086] The bearing 264 is mounted on the third connecting rod 262 and the fourth connecting rod 265 and connected by a plug bolt 263 .

[0087] One side of the fourth connecting rod 265 is connected to the polished rod slider 261 , and the other side is hingedly connected to the wave cabin 13 via a plug bolt 268 .

[0088] The second polished rod slider 266 is loosely sleeved on the second polished rod 267 to form a cylindrical pair, and the rotational freedom is limited by the third connecting rod 262, and can only slide linearly along the second polished rod 267.

[0089] The outer side of the pectoral fin folding and unfolding mechanism 2 is coated with a silicone film to increase the force-bearing area when the pectoral fins of the underwater robot are unfolded to capture energy, thereby improving energy utilization.

[0090] The working principle of the pectoral fin folding and unfolding mechanism 2: the pectoral fin folding and unfolding mechanism 2 is composed of an upper and lower layer of scissor-type connecting rod mechanisms, the first scissor-type connecting rod group 25 is an active connecting rod group, and the second scissor-type connecting rod group 26 is a driven connecting rod group. When the micro reduction motor 27 drives the screw 22 to rotate continuously, the screw flange 24 drives the first scissor-type connecting rod group 25 to fold and unfold, and the movement of the wave cabin 13 will drive the driven connecting rod group to fold and unfold.

[0091] The fuselage 3 includes a fuselage top cover 31 , a sealing gasket 32 ​​, and a fuselage cabin 33 .

[0092] The fuselage cabin 33 is equipped with a wave energy conversion device 4 , a center of gravity adjustment device 5 , and a control module 6 .

[0093] The wave energy conversion device 4 includes a two-stage gear speed increasing mechanism 41 , a generator 42 , a piezoelectric vibrator 43 , and a piezoelectric paddle shaft 44 .

[0094] More specifically, the foldable pectoral fins on both sides of the robot are hingedly connected to the fuselage cabin 33 through the pectoral fin rotation shaft 28 installed on the pectoral fin bracket 21, one side of the pectoral fin rotation shaft 28 is connected to the pectoral fin bracket 21, and the other side is connected to the input gear of the two-stage gear speed increaser mechanism 41, and the output gear of the two-stage gear speed increaser mechanism 41 is connected to the generator 42.

[0095] The generator 42 and the piezoelectric vibrator 43 are directly mounted on a support below the fuselage cabin 33 .

[0096] The piezoelectric vibrator 43 includes a piezoelectric ceramic 431 and a copper sheet 432 . Three piezoelectric ceramics 431 are mounted on the copper sheet 432 , and shear grooves are alternately opened on the copper sheet 432 , which is beneficial to increase the bending deformation of the piezoelectric vibrator 43 under the excitation of the piezoelectric paddle shaft 44 .

[0097] The working principle of the wave energy conversion device 4 is as follows: under the action of waves, the pectoral fins on both sides of the robot unfold and swing relative to the fuselage 3, and the swing of the pectoral fins is converted into the rotation of the generator 42 through the two-stage gear speed increase mechanism 41, so that the generator generates electricity. At the same time, the piezoelectric paddle shaft 44 is the intermediate shaft of the two-stage gear speed increase mechanism 41, so the reciprocating swing of the pectoral fins will also cause the piezoelectric paddle shaft 44 to reciprocate. It is worth noting that the slot on the piezoelectric paddle shaft 44 needs to clamp the cantilever end of the piezoelectric vibrator 43 during installation, so that the piezoelectric paddle shaft 44 will force the piezoelectric vibrator 43 to bend reciprocatingly during the reciprocating rotation, thereby generating electricity using piezoelectric ceramics and improving the efficiency of wave energy utilization.

[0098] The center of gravity adjustment device 5 includes a stepping motor 51 , a motor bracket 52 , a screw 53 , a battery 54 , a screw flange 55 , a weight holder upper cover 56 , a weight holder 57 , and an optical axis 58 .

[0099] The stepper motor 51 is mounted on the motor bracket 52 , and the motor bracket 52 is mounted on a support below the fuselage cabin 33 .

[0100] One side of the screw rod 53 is connected to the stepping motor 51 via a thread, and the other side is directly stuck in a U-shaped groove reserved at the rear of the fuselage cabin 33 .

[0101] The battery 54 is both an energy storage and supply module and a weight of the center of gravity adjustment device 5 . The battery 54 is pressed into two grooves of the weight holder 57 by the weight holder upper cover 56 . The weight holder 57 is connected to the screw flange 55 .

[0102] The optical axis 58 passes through the two circular holes below the weight retaining frame 57, and the front and rear sides of the optical axis 58 are stuck in the U-shaped grooves reserved at the front and rear of the fuselage cabin 33, which are used to limit the swing of the weight, maintain the stability of the weight during the linear movement, and ensure the stability of the robot body posture when adjusting the center of gravity.

[0103] The working principle of the center of gravity adjustment device 5 is as follows: when the stepper motor 51 rotates continuously, the screw flange 55 drives the weight to move along the center line of the underwater robot body, thereby changing the axial position of the robot's center of gravity, changing the pitch posture of the robot during movement, and coordinating the movement of the robot to achieve floating and diving.

[0104] The working method of the underwater robot is as follows: when the underwater robot is under the water surface, the robot is in motion mode, the pectoral fins can be folded, the folded size of the single pectoral fin is 180 mm, the control module alternately supplies power to the first positive electrode and the second positive electrode, and the pectoral fin swing axis is pulled to reciprocate by alternately contracting the one-way shape memory alloy wire, and the five groups of fin swing units alternately swing, so that the pectoral fins on both sides of the robot produce flexible fluctuations to achieve motion. During motion, the folded pectoral fins of the underwater robot are conducive to reducing the robot's navigation resistance and reducing energy consumption.

[0105] When the robot needs to float, the center of gravity adjustment device controls the weight to move to the rear of the robot, the center of gravity of the robot moves backward, the head posture is tilted upward, the pectoral fin undulating mechanism continues to fluctuate, and the robot moves toward the water surface.

[0106] When the robot is on the water surface, the robot is in the energy capture mode, the control module controls the micro reduction motor to rotate, drives the foldable pectoral fin to unfold, the unilateral pectoral fin can be extended to 320mm, the extension rate is 178%, the pectoral fin reciprocates relative to the fuselage under the excitation of waves, and drives the generator and piezoelectric vibrator to generate electricity through the wave energy conversion mechanism. When generating electricity, the pectoral fins of the underwater robot are unfolded, which can increase the force area of ​​the pectoral fins under the excitation of waves and improve the wave energy generation power.

[0107] When the robot needs to dive, the control module controls the micro reduction motor to rotate, driving the foldable pectoral fins to fold, and the center of gravity adjustment device controls the weight to move to the front of the robot body. The center of gravity of the robot moves forward, the head posture leans down, the pectoral fin undulating mechanism continues to fluctuate, and the robot moves underwater.

[0108] The present invention uses shape memory alloy to design the robot's fin swing unit. Preferably, two one-way shape memory alloy wires are used to design a flexible driver. By reasonably designing the relative positions of the positive and negative electrodes and the fin swing axis, the robot's fins can be driven to swing back and forth. Multiple groups of shape memory alloy wires drive a fin swing unit at the same time, which simply and efficiently improves the driving force, speeds up the motion response, and effectively reduces the weight and volume of the robot's drive mechanism, solving the problem that the traditional rigid drive solution cannot meet the structural limitations of micro-sized underwater robots due to its large size and weight, and thus is difficult to meet the driving needs of micro-sized robots. The undulating pectoral fin has a certain degree of flexibility, which is closer to the movement mode of biological muscle drive.

[0109] The present invention adopts foldable pectoral fins. When in motion, the pectoral fins are folded, which effectively reduces the navigation resistance of the robot. When in energy-capturing state, the pectoral fins are unfolded, which increases the force-bearing area of ​​the robot when capturing energy, effectively improves the energy utilization efficiency of the robot to achieve self-power supply by using the raft-type wave energy conversion principle, and enhances the robot's endurance when working underwater. The foldable pectoral fins organically combine the robot's efficient wave propulsion with raft-type wave energy power generation.

[0110] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0111] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A self-powered underwater bionic robot driven by a shape memory alloy, characterized in that: It includes a pectoral fin wave mechanism, a pectoral fin folding and unfolding mechanism, a fuselage, a wave energy conversion device, a center of gravity adjustment device, a battery and a control module, wherein: The pectoral fin undulating mechanism and the pectoral fin folding mechanism form a foldable pectoral fin, and the foldable pectoral fin is hinged to the fuselage through a pectoral fin rotation axis; When the foldable pectoral fins are in the unfolded state, they capture wave energy to drive the wave energy conversion device to generate electricity and charge the battery; when in the folded state, the pectoral fin wave mechanism generates a quasi-sine propulsion wave; The control module, the wave energy conversion device, and the center of gravity adjustment device are all installed in the fuselage cabin; The control module controls the movement of the foldable pectoral fin; The pectoral fin undulation mechanism includes a membrane, a fin swing unit, an undulation cabin, a pectoral fin undulation cabin cover, a positive electrode assembly, a negative electrode assembly, and a shaft end cover, wherein: The wave cabin body and the pectoral fin wave cabin cover are connected by bolts, and a sealing gasket is installed between the two; There are multiple groups of fin ray swinging units, and the multiple groups of fin ray swinging units are covered with thin films, so that the multiple groups of fin rays can swing alternately; The positive electrode assembly and the negative electrode assembly are assembled in the shifting cabin; The fin swing unit includes a carbon fiber rod, a fin connector, a first one-way shape memory alloy wire, a second one-way shape memory alloy wire, a fin swing shaft, a sleeve, a flange bearing, a first sealing ring, and a second sealing ring, wherein: The carbon fiber rod is bonded to the fin ray connecting member, and the fin ray connecting member is connected to the fin ray swing axis via a pin; The sleeve presses the flange bearing onto one side of the first sealing ring, the other side of the first sealing ring is pressed against the wave chamber, and the second sealing ring is installed in the shaft hole of the wave chamber; Each group of fin swing units is axially positioned by an insulating pad; One side of the first one-way shape memory alloy wire and the second one-way shape memory alloy wire is wound around the positive electrode assembly, passes through the small hole of the fin swing axis in the opposite direction, and the other side is wound around the negative electrode assembly.

2. The shape memory alloy driven self-powered underwater bionic robot according to claim 1, characterized in that: The positive electrode assembly comprises a first positive electrode, a second positive electrode and an insulating connector, wherein: One side of the first one-way shape memory alloy wire is wound around the first positive electrode, and one side of the second one-way shape memory alloy wire is wound around the second positive electrode; Each group of positive electrodes is connected via the insulating connector 164 .

3. The shape memory alloy driven self-powered underwater bionic robot according to claim 1, characterized in that: The negative electrode assembly comprises a negative electrode and an insulating connector, and each group of negative electrodes is connected by the insulating connector.

4. The shape memory alloy driven self-powered underwater bionic robot according to claim 1, characterized in that: The pectoral fin folding and unfolding mechanism includes a pectoral fin bracket, a lead screw, a polished rod, a lead screw flange, a first scissor-type connecting rod group, a second scissor-type connecting rod group and a micro reduction motor, wherein: The lead screw, polished rod and micro reduction motor are all arranged on the pectoral fin bracket; The pectoral fin folding and unfolding mechanism is connected to the undulating cabin of the pectoral fin undulating mechanism via a scissor-type connecting rod group; One of the connecting rods of the first scissor-type connecting rod group is connected to a screw flange arranged on the screw; The micro reduction motor drives the first scissor-type connecting rod group to move under the limit of the lead screw; The second scissor-type connecting rod group is arranged on the polished rod, and when the first scissor-type connecting rod group moves, it drives the second scissor-type connecting rod group to move under the limit of the polished rod.

5. The shape memory alloy driven self-powered underwater bionic robot according to claim 4, characterized in that: The first scissor-type connecting rod assembly includes a flange connector, a first connecting rod, a plug bolt, a bearing, a second connecting rod, a first polished rod slider and a first polished rod, wherein: The flange connector is connected to the screw flange via bolts; One side of the first connecting rod is hingedly connected to the pectoral fin bracket by a plug bolt, and the other side is connected to the first polished rod slider; The bearing is mounted on the first connecting rod and the second connecting rod and connected by plug bolts; One side of the second connecting rod is connected to the flange connector, and the other side is hingedly connected to the wave cabin through a plug bolt; The first polished rod slider is sleeved on the first polished rod to form a cylindrical pair, and the first connecting rod limits the rotational freedom and slides linearly along the first polished rod.

6. The shape memory alloy driven self-powered underwater bionic robot according to claim 1, characterized in that: The wave energy conversion device comprises a two-stage gear speed increasing mechanism, a generator, a piezoelectric vibrator and a piezoelectric paddle shaft, wherein: The foldable pectoral fin is hinged to the fuselage through the pectoral fin rotation axis; One side of the pectoral fin rotation axis is connected to the pectoral fin bracket of the foldable pectoral fin, and the other side is connected to the input gear of the secondary gear speed increasing mechanism; The output gear of the secondary gear speed increasing mechanism is connected to the generator; The generator and the piezoelectric vibrator are directly mounted on a support below the fuselage cabin.

7. The shape memory alloy driven self-powered underwater bionic robot according to claim 6, characterized in that: The piezoelectric vibrator comprises piezoelectric ceramics and a copper sheet, the piezoelectric ceramics are mounted on the copper sheet, and shear grooves are alternately opened on the copper sheet.

8. The shape memory alloy driven self-powered underwater bionic robot according to claim 1, characterized in that: The center of gravity adjustment device includes a stepper motor, a motor bracket, a screw, a battery, a screw flange, a weight holder upper cover, a weight holder, and an optical axis, wherein: The stepper motor is mounted on the motor bracket, and the motor bracket is mounted on a support below the fuselage cabin; One side of the screw rod is connected to the stepping motor via a thread, and the other side is directly stuck in the U-shaped groove reserved at the rear of the fuselage cabin; The battery is used as a weight of the center of gravity adjustment device, and is pressed tightly into two grooves of the weight holder by the upper cover of the weight holder, and the weight holder is connected to the screw flange; The optical axis passes through two circular holes below the weight retaining frame, and the front and rear sides of the optical axis are clamped in U-shaped grooves reserved at the front and rear of the fuselage cabin.

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