Underwater bionic double-fin robot with rolling device and control method of underwater bionic double-fin robot

Abstract

The invention discloses an underwater bionic double-fin robot with a rolling device and a control method thereof.The underwater bionic double-fin robot is of a vertically-symmetrical and bilaterally-symmetrical structure and comprises a shell, a double-fin module, a transmission module, a rolling module and a control system.The rolling module comprises three planet gears, a sun gear and a planet carrier; the sun gear is rigidly connected with the output shaft, the planet carrier is slidably connected with the planet gears through bearings, and the three planet gears are internally meshed with the planet carrier and externally meshed with the sun gear; through the change of mass distribution of the three planet wheels when the rotating mechanism rotates, the mass center, originally close to the center line of the lower portion, of the robot shifts to one side of the body, the two fins swing in a matched mode to provide two lateral forces in the opposite directions at different depths, and the robot is assisted in completing the rolling action. By adjusting the weight distribution of the rolling module, the robot can roll in the horizontal axis direction and keep the state after rolling; the robot can be assisted to complete rolling by adjusting the opposite offset middle position and the opposite swinging direction of the double-fin module. The robot is simple and compact in structure, and through cooperation of the rolling module and the double-fin module, conversion of rolling motion and motion postures of the robot can be achieved.

Description

Technical Field

[0001] The invention belongs to the field of underwater bionic robots, and in particular relates to an underwater bionic double-fin robot with a rolling device and a control method thereof. Background Art

[0002] With the continuous advancement of science and technology, underwater robots are increasingly used in the fields of ocean exploration, resource development, and environmental monitoring. Fish swim by swinging their bodies and fins, showing efficient propulsion and excellent maneuverability. Bionic fish-shaped robots can flexibly shuttle in complex underwater environments by simulating the swimming method of fish, showing broad application prospects.

[0003] At present, most bionic fish-shaped robots, although they can achieve high-speed and high-maneuverability swimming movements, almost lack the ability to roll horizontally, which seriously restricts the robots from performing tasks in narrow horizontal spaces underwater. Even though a few robot fish can perform backflips by flapping a pair of pectoral fins, they still cannot roll effectively when crossing narrow spaces.

[0004] Sunfish, as an uncommon marine fish, has a huge dorsal fin and a huge anal fin. They rely on controlling the swing of their fins to move forward, turn, ascend and dive, and roll horizontally. However, the existing double-fin robots designed based on the sunfish still have problems such as difficult control and insufficient flexibility in certain specific situations (such as when rolling or adjusting specific postures). Therefore, adding a rolling function to the double-fin robot to improve its flexibility and control accuracy in underwater movement is of great significance to promoting the application of bionic robots. Summary of the invention

[0005] In order to solve the shortcomings of the prior art, a tumbling device is added to the underwater bionic dual-fin robot to realize the robot's tumbling motion and motion posture transformation, so as to complete more complex and flexible underwater motion and meet the purpose of diversified applications. The present invention adopts the following technical solutions: An underwater bionic twin-fin robot with a rolling device comprises a shell, a twin-fin module, a transmission module, a control system and a rolling module. The twin-fin modules are symmetrically mounted at the upper and lower ends of the outer side of the shell. The control system shifts the center of gravity of the robot through the rolling module, and controls the twin-fin module through the transmission module to perform reverse swinging of the upper and lower twin fins with opposite offset mid-positions, and cooperates with the rolling module to make the robot roll up and down.

[0006] Furthermore, the transmission module includes an upper transmission shaft, a lower transmission shaft and a flat transmission shaft, the dual-fin module includes an upper fin sub-module and a lower fin sub-module, and the tumbling module includes a planetary gear, a sun gear and a gear ring; the upper transmission shaft is connected to the upper fin sub-module, the lower transmission shaft is connected to the lower fin sub-module, the sun gear is rigidly connected to the flat transmission shaft through a coupling, and meshes with a group of planetary gears around the orbiter, a group of planetary gears mesh with the inner part of the gear ring, the planetary gears are made of a metal material with high density, have a large weight, and are evenly arranged in odd numbers on the periphery of the sun gear, so that while ensuring the stability of the robot, the center of gravity of the robot can be changed with a little effort, the tooth ratio of the sun gear, planetary gear and gear ring is 18:31:81, and the gear ring is interference fit with the lower shell of the tumbling module; the waterproofing measures between the upper and lower transmission shafts and the shell include two layers of oil seals, and waterproof material is filled in the middle.

[0007] Furthermore, the tumbling module also includes a planetary carrier, which is slidably connected to the planetary wheels via bearings, so that the distance between the three planetary wheels remains relatively stable.

[0008] Furthermore, the housing comprises an upper housing, a lower housing and a tumbling module waterproof housing arranged symmetrically between the upper housing and the lower housing, the upper housing comprises a flat upper gear ring groove, a flat upper tumbling motor groove, and a flat upper flat bearing groove, the lower housing comprises a flat lower gear ring groove, a flat lower tumbling motor groove, and a flat lower flat bearing groove; the tumbling module waterproof housing comprises a front waterproof cover and a rear waterproof cover; the transmission module comprises a flat oil seal and a flat bearing; The gear ring groove formed by the upper flat gear ring groove and the lower flat gear ring groove is used to fix the tumbling module waterproof shell and then fix the tumbling module; the tumbling motor groove formed by the upper flat tumbling motor groove and the lower flat tumbling motor groove is used to fix the tumbling motor; the upper flat bearing groove and the lower flat bearing groove are connected by a flat transmission shaft through a flat bearing support; The front waterproof cover is provided with a waterproof structure consistent with the motor housing, which is used to fix the flat oil seal, the flat transmission shaft and the flat bearing; the gear ring is interference fit with the rear waterproof cover, and the flat transmission shaft passes through the front waterproof cover and the flat bearing to provide deflection power for the tumbling module.

[0009] The tumbling module housing is splined with the upper and lower housings to fix the gears of the tumbling module. The bearing supports the horizontal transmission shaft, which is connected to the sun gear through molding and is the power source of the entire tumbling module.

[0010] Furthermore, the upper fin submodule includes an upper fin fixed part and an upper fin movable part, and the lower fin submodule includes a lower fin fixed part and a lower fin movable part, which provides a faster and more convenient way to replace the fins, reduces the wear on the shaft, and prolongs the life of the whole machine; the transmission module also includes an upper outer oil seal, an upper inner oil seal, a lower outer oil seal, a lower inner oil seal, an upper bearing, and a lower bearing; The upper fin fixing part and the upper fin movable part are connected and combined into a complete fin by bolts. The hole of the upper fin fixing part is arranged in cooperation with the upper transmission shaft. The upper transmission shaft passes through the upper bearing fixed in the upper bearing limit groove from the inside of the shell, and passes through the upper outer oil seal fixed in the upper outer oil seal groove. The other end of the upper transmission shaft passes through the end face of the upper inner oil seal inside the shell and is fixed to one end of the motor, so that the torque transmitted by the motor is transmitted to the double fin module through the transmission shaft; the other end of the transmission shaft is semicircular, which is used to position and install the upper and lower fin fixing parts and is fixed by bolts. The end of the transmission shaft is formed and connected with the surface of the motor and connected by bolts. The material of the transmission shaft is 6061 aluminum, which has a relatively low density and a strong anti-rust effect. The lower fin fixing part and the lower fin movable part are combined into a complete fin through bolt connection. The hole of the lower fin fixing part is matched with the lower transmission shaft. The lower transmission shaft passes through the lower bearing fixed in the lower bearing limiting groove from the inside of the shell and passes through the lower outer oil seal fixed in the lower outer oil seal groove. The other end of the lower transmission shaft passes through the end face of the lower inner oil seal inside the shell and is fixed to the other end of the motor.

[0011] Furthermore, the housing includes an upper housing, a lower housing and a motor housing disposed between the upper and lower housings, and the motor housing includes an upper motor housing and a lower motor housing; the housing is formed of resin by 3D printing, and is symmetrical in both vertical and horizontal directions, providing mechanical structural conditions for smooth rolling; The upper housing includes an upper motor slot, an upper bearing slot, an upper bearing limit slot, and an upper outer oil seal slot, and the lower housing includes a lower motor slot, a lower bearing slot, a lower bearing limit slot, and a lower outer oil seal slot; The upper motor shell comprises an upper motor upper shell and an upper motor lower shell, the lower motor shell comprises a lower motor upper shell and a lower motor lower shell, the upper motor upper shell comprises an upper oil seal groove, an upper upper spline, an upper inner O-type rubber ring groove, an upper outer O-type rubber ring groove, an upper motor positioning pin, and an upper transmission shaft hole, and the upper motor lower shell comprises an upper wire slot hole, an upper stop groove, and upper and lower splines; the upper motor upper shell positions the motor through the upper motor positioning pin, and the motor is connected to the motor at the bottom of the upper motor lower shell with screws, the outer wall of the upper motor upper shell is extruded and matched with the motor lower shell through the O-type rubber ring installed in the upper inner O-type rubber ring groove, and the upper motor upper shell is fitted with the upper stop groove, the upper transmission shaft passes through the upper motor upper shell through the upper transmission shaft hole and the upper inner oil seal, the O-type rubber ring is sleeved on the upper outer O-type rubber ring groove and squeezes the upper motor groove to form an axial seal, providing a waterproof environment for the motor; the upper motor groove is connected to the upper motor lower shell through the upper upper spline and the upper and lower splines and the upper motor upper shell, and is fixed with bolts.

[0012] The motor is protected by a motor housing, and the motor power data line enters the motor housing through a wire slot and is connected to the motor. The motor and the housing are fixed to each other through splines and fixed by bolts.

[0013] The waterproof measures for the motor housing include double O-rings squeezed between the upper and lower housings, O-rings squeezed between the upper motor housing and the upper housing, and waterproof materials filled at the wire holes and at the joints between the upper and lower covers.

[0014] Furthermore, the shell includes a symmetrically arranged upper shell, a lower shell and a battery shell arranged between the upper and lower shells, the upper shell includes a flat upper battery slot, and the lower shell includes a flat lower battery slot; the battery shell includes a battery upper shell and a battery lower shell; the battery slot formed by the flat upper battery slot and the flat lower battery slot is used to fix the internal battery.

[0015] A control method for an underwater bionic twin-fin robot with a rolling device, wherein a control system controls a rolling module to rotate so as to shift the center of gravity of the robot, and controls a transmission module so as to make the upper and lower fins of the twin-fin module, which are opposite to the offset center, swing in opposite directions, and cooperate with the rolling module to make the robot roll up and down. After rolling, the rolling module is stopped from rotating so as to stabilize the center of gravity of the robot, and the twin-fin module returns to the zero-degree offset center.

[0016] Furthermore, the method specifically includes the following steps: Step 1: Put the robot into water and put it in a slightly positive buoyancy state; Step 2: Initialize the dual-fin module through the control system so that the upper and lower fins are at a zero-degree neutral position; Step 3: When the robot is in a balanced state, the control system controls the transmission module to drive the upper and lower fins of the dual-fin module to swing at the zero-degree offset center, at the same frequency and in the same direction (i.e., the phase difference is 0 degrees). At this time, the robot is in a linear motion state and remains vertical. Step 4: When the robot performs a rolling action, the control system controls the rolling module to rotate clockwise (or counterclockwise). The rotation direction controls the rolling direction of the robot as a whole. The operation of the rolling module causes the center of gravity, which is originally located below the left and right symmetrical center of the robot, to shift to the upper left (or upper right), gradually tilting from the vertical state to one side of the horizontal plane; Step 5: At the same time, the control system controls the median offset of the upper and lower fins of the dual-fin module to opposite angles, and the two fins swing in opposite directions, which causes the robot to generate an outward pulling force in the horizontal direction of the two fins, accelerating the speed at which the robot tilts from a vertical state to a horizontal direction, and assisting the robot to complete the rolling action; Step 6: After the robot completes the tumbling action (i.e., flips 90 degrees from the original vertical state to the horizontal state), stop the tumbling module from rotating and keep its center of gravity in a balanced position (i.e., rotates 90 degrees from the original 0-degree position). At the same time, the dual-fin module returns to the zero-degree offset center position, swings at the same frequency and in the same direction, so that the robot maintains its current motion posture.

[0017] Furthermore, in step 5, the median offset angles of the upper and lower fins are opposite, and the phase difference of the reverse swinging of the double fins is 180 degrees.

[0018] The advantages and beneficial effects of the present invention are: The underwater bionic robot of the present invention takes the sunfish as the bionic prototype and adopts a structural design that is symmetrical in both upper and lower directions and in both left and right directions, so that its overall weight distribution is uniform and symmetrical, creating structural conditions for realizing tumbling movements, and the robot is spindle-shaped as a whole with a streamlined appearance, which reduces the impact from the front water flow and has good hydrodynamic characteristics; the dual-fin module and the tumbling device of the underwater bionic robot of the present invention adopt a motor direct connection method, which can realize a larger range of swing frequencies and swing amplitudes, and can adjust the swing phase and offset center position in real time, which creates control conditions for realizing tumbling movements, and the structure is simple and compact, which realizes the lightweight and miniaturization of the robot and reduces the complexity of the robot system; the underwater bionic robot of the present invention, by adding a tumbling device on the basis of the dual-fin robot, makes the tumbling device and the dual-fin device move in coordination, can realize stable tumbling movements and motion posture switching, expands the application scenarios of the robot, and provides technical support for the robot's multiple motion modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the overall structure of the robot in an embodiment of the present invention.

[0020] Figure 2 Schematic diagram of the outer structure of the robot in an embodiment of the present invention.

[0021] Figure 3 Schematic diagram of the structure of the tumbling module in an embodiment of the present invention.

[0022] Figure 4a Schematic diagram of the upper shell structure in an embodiment of the present invention.

[0023] Figure 4b Schematic diagram of the lower shell structure in an embodiment of the present invention.

[0024] Figure 5 This is a structural diagram of the waterproof housing of the rollover module in an embodiment of the present invention.

[0025] Figure 6 Schematic diagram of the internal structure of the shell in an embodiment of the present invention.

[0026] Figure 7 This is an assembly diagram of the output shaft of the transmission module in an embodiment of the present invention.

[0027] Figure 8 Schematic diagram of the structure of the upper fin module in an embodiment of the present invention.

[0028] Figure 9aThis is an assembly diagram of the output shaft of the upper housing in an embodiment of the present invention.

[0029] Figure 9b This is an assembly diagram of the output shaft of the lower housing in an embodiment of the present invention.

[0030] Fig.10 Schematic diagram of the upper motor housing structure in an embodiment of the present invention.

[0031] Fig.11 Schematic diagram of the state of the robot after completing the rolling action in an embodiment of the present invention.

[0032] Explanation of the markings in the figure: 1. Shell; 2. Dual fin module; 3. Transmission module; 4. Control system; 5. Rollover module; 11. Upper shell; 12. Lower shell; 13. Motor shell; 14. Battery shell; 15. Rollover module waterproof shell; 21. Upper fin module; 22. Lower fin module; 31. Upper transmission shaft; 32. Lower transmission shaft; 33. Flat transmission shaft; 34. Upper outer oil seal; 35. Upper inner oil seal; 36. Lower outer oil seal; 37. Lower inner oil seal; 38. Flat oil seal; 39. Upper bearing ; 310, lower bearing; 311, flat bearing; 51, planetary gear; 52, sun gear; 53, gear ring; 54, planet carrier; 111, upper battery slot; 112, upper bearing slot; 113, upper bearing limit slot; 114, upper outer oil seal slot; 115, flat upper battery slot; 116, flat upper gear ring slot; 117, flat upper tumbling motor slot; 118, flat upper flat bearing slot; 121, lower motor slot; 122, lower bearing slot; 123 lower bearing limit slot; 124, lower outer oil seal slot; 125, flat lower battery slot; 126, flat lower gear ring slot; 127, flat lower rolling motor slot wheel; 128, flat lower flat bearing slot; 131, upper motor housing; 132, lower motor housing; 141, upper battery housing; 142, lower battery housing; 151, front waterproof cover; 152, rear waterproof cover; 211, upper fin fixed part; 212, upper fin movable part; 221, lower fin fixed part; 222, lower fin movable part; 1311, upper Motor upper shell; 1312, upper motor lower shell; 1321, lower motor upper shell; 1322, lower motor lower shell; 13111, upper oil seal groove; 13112, upper upper spline; 13113, upper inner O-type rubber ring groove; 13114, upper outer O-type rubber ring groove; 13115, upper motor locating pin; 13116, upper transmission shaft hole; 13121, upper wire slot hole; 13122, upper stop slot; 13123, upper and lower splines. DETAILED DESCRIPTION

[0033] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0034] like Figure 1, Figure 2 As shown, an underwater bionic twin-fin robot with a rolling device includes a shell 1, a twin-fin module 2, a transmission module 3, a control system 4 and a rolling module 5. The twin-fin module 2 is symmetrically installed at the upper and lower ends of the outer side of the shell 1. The control system 4 shifts the center of gravity of the robot through the rolling module 5, and controls the twin-fin module 2 through the transmission module 3 to swing the upper and lower twin fins in opposite offset positions in the opposite direction, and cooperates with the rolling module 5 to make the robot roll up and down.

[0035] like Figure 3 As shown, the transmission module 3 includes an upper transmission shaft 31, a lower transmission shaft 32 and a flat transmission shaft 33, the dual-fin module 2 includes an upper fin module 21 and a lower fin module 22, and the tumbling module 5 includes a planetary gear 51, a sun gear 52, and a gear ring 53; the upper transmission shaft 31 is connected to the upper fin module 21, the lower transmission shaft 32 is connected to the lower fin module 22, the sun gear 52 is rigidly connected to the flat transmission shaft 33 through a coupling, and meshes with a group of planetary gears 51 around the surround, and a group of planetary gears 51 are meshed with the gear ring 53. The planetary gears are made of a metal material with a high density and a large weight, and are evenly arranged in odd numbers on the periphery of the sun gear, so that while ensuring the stability of the robot, the center of gravity of the robot can be changed with a little effort. The gear ratio of the sun gear, the planetary gear and the gear ring is 18:31:81, and the gear ring is interference fit with the lower shell of the tumbling module; the waterproofing measures between the upper and lower transmission shafts and the shell include two layers of oil seals, and waterproof material is filled in the middle.

[0036] The tumbling module 5 further includes a planet carrier 54 , which is slidably connected to the planetary wheels 51 via bearings, so that the distance between the three planetary wheels 51 remains relatively stable.

[0037] like Figure 4a , Figure 4b ,and Figures 5 to 7 As shown, the housing 1 includes an upper housing 11, a lower housing 12 and a tumbling module waterproof housing 15 arranged symmetrically between the upper and lower housings, the upper housing 11 includes a flat upper gear ring groove 116, a flat upper tumbling motor groove 117, and a flat upper flat bearing groove 118, the lower housing 12 includes a flat lower gear ring groove 126, a flat lower tumbling motor groove 127, and a flat lower flat bearing groove 128; the tumbling module waterproof housing 15 includes a front waterproof cover 151 and a rear waterproof cover 152; the transmission module 3 includes a flat oil seal 38 and a flat bearing 311; The gear ring groove formed by the upper flat gear ring groove 116 and the lower flat gear ring groove 126 is used to fix the tumbling module waterproof shell 15 and then fix the tumbling module 5; the tumbling motor groove formed by the upper flat tumbling motor groove 117 and the lower flat tumbling motor groove 127 is used to fix the tumbling motor; the upper flat bearing groove 118 and the lower flat bearing groove 128 are supported and connected by the flat transmission shaft 33 through the flat bearing 311; The front waterproof cover 151 is provided with a waterproof structure consistent with the motor housing 13, which is used to fix the flat oil seal 38, the flat transmission shaft 33 and the flat bearing 311; the gear ring 53 is interference fit with the rear waterproof cover 152, and the flat transmission shaft 33 passes through the front waterproof cover 151 and the flat bearing 311 to provide deflection power for the tumbling module 5.

[0038] The tumbling module housing is splined with the upper and lower housings to fix the gears of the tumbling module. The bearing supports the horizontal transmission shaft, which is connected to the sun gear through molding and is the power source of the entire tumbling module.

[0039] like Figure 8 , Figure 9a , Figure 9b As shown, the upper fin submodule 21 includes an upper fin fixed part 211 and an upper fin movable part 212, and the lower fin submodule 22 includes a lower fin fixed part 221 and a lower fin movable part 222, which provides a faster and more convenient way to replace the fins, reduces the wear on the shaft, and prolongs the life of the whole machine; the transmission module 3 also includes an upper outer oil seal 34, an upper inner oil seal 35, a lower outer oil seal 36, a lower inner oil seal 37, an upper bearing 39, and a lower bearing 310; The upper fin fixing part 211 and the upper fin movable part 212 are connected and combined into a complete fin by bolts. The hole of the upper fin fixing part 211 is matched with the upper transmission shaft 31. The upper transmission shaft 31 passes through the upper bearing 39 fixed in the upper bearing limit groove 113 from the inside of the housing 1, and passes through the upper outer oil seal 34 fixed in the upper outer oil seal groove 114. The other end of the upper transmission shaft 31 passes through the end face of the upper inner oil seal 35 inside the housing 1 and is fixed to one end of the motor, so that the torque transmitted by the motor is transmitted to the double fin module through the transmission shaft; the other end of the transmission shaft is semicircular, which is used to position and install the upper and lower fin fixing parts and is fixed by bolts. The end of the transmission shaft is formed and connected with the surface of the motor and connected by bolts. The material of the transmission shaft is 6061 aluminum, which has a relatively low density and a strong anti-rust effect. The lower fin fixing part 221 and the lower fin movable part 222 are combined into a complete fin through bolt connection. The hole of the lower fin fixing part 221 is matched with the lower transmission shaft 32. The lower transmission shaft 32 passes through the lower bearing 310 fixed in the lower bearing limit groove 123 from the inside of the shell 1, and passes through the lower outer oil seal 36 fixed in the lower outer oil seal groove 124. The other end of the lower transmission shaft 32 passes through the end face of the lower inner oil seal 37 inside the shell 1 and is fixed to the other end of the motor.

[0040] The housing 1 includes an upper housing 11, a lower housing 12 and a motor housing 13 disposed between the upper and lower housings, wherein the motor housing 13 includes an upper motor housing 131 and a lower motor housing 132; the housing is formed by 3D printing of resin, and is symmetrical in both vertical and horizontal directions, providing mechanical structural conditions for smooth rolling; like Fig.10 As shown, the upper housing 11 includes an upper motor slot 111, an upper bearing slot 112, an upper bearing limiting slot 113, and an upper outer oil seal slot 114, and the lower housing 12 includes a lower motor slot 121, a lower bearing slot 122, a lower bearing limiting slot 123, and a lower outer oil seal slot 124; The upper motor housing includes an upper motor upper housing 1311 and an upper motor lower housing 1312, the lower motor housing 132 includes a lower motor upper housing 1321 and a lower motor lower housing 1322, the upper motor upper housing 1311 includes an upper oil seal groove 13111, an upper spline 13112, an upper inner O-type rubber ring groove 13113, an upper outer O-type rubber ring groove 13114, an upper motor positioning pin 13115, and an upper transmission shaft hole 13116, the upper motor lower housing 1312 includes an upper wire slot 13121, an upper stop slot 13122, and upper and lower splines 13123; the upper motor upper housing 1311 locates the motor through the upper motor positioning pin 13115, and at the bottom of the upper motor lower housing 1312 The motor is connected with screws, and the outer wall of the upper motor shell 1311 is squeezed and matched with the motor lower shell 1312 through the O-type rubber ring installed in the upper inner O-type rubber ring groove 13113, and the upper motor shell 1311 is fitted with the upper stop groove 13122, and the upper transmission shaft 31 passes through the upper motor shell 1311 through the upper transmission shaft hole 13116 and the upper inner oil seal 35. The O-type rubber ring is sleeved on the upper outer O-type rubber ring groove 13114 and squeezes the upper motor groove 111 to form an axial seal, providing a waterproof environment for the motor; the upper motor groove 111 is connected with the upper motor lower shell 1312 through the upper spline 13112 and the upper and lower splines 13123 and the upper motor shell 1311 and the upper motor lower shell 1312, and are fixed with bolts.

[0041] The motor is protected by a motor housing, and the motor power data line enters the motor housing through a wire slot and is connected to the motor. The motor and the housing are fixed to each other through splines and fixed by bolts.

[0042] The waterproof measures for the motor housing include double O-rings squeezed between the upper and lower housings, O-rings squeezed between the upper motor housing and the upper housing, and waterproof materials filled at the wire holes and at the joints between the upper and lower covers.

[0043] The shell 1 includes a symmetrically arranged upper shell 11, a lower shell 12 and a battery shell 14 arranged between the upper and lower shells, the upper shell 11 includes a flat upper battery slot 115, and the lower shell 12 includes a flat lower battery slot 125; the battery shell 14 includes a battery upper shell 141 and a battery lower shell 142; the battery slot formed by the flat upper battery slot 115 and the flat lower battery slot 125 is used to fix the internal battery.

[0044] In an embodiment of the present invention, the upper shell 11 and the lower shell 12 are connected by 4mm bolts and 4mm square nuts, and the battery shell 14 is interference fit with the battery slot. A V-shaped groove is formed between the contact between the upper and lower covers of the battery shell 14, which is used for later waterproof sealant sealing. The motor shell 13 and the motor slot are positioned by splines, and the upper and lower covers of the motor shell 13 are axially sealed by a double-layer O-ring. The motor shell 13 is fixed in the motor slot by 3mm bolts and 3mm square nuts. A V-shaped groove is formed between the contact between the upper and lower covers of the motor shell 13, which is used for later waterproof sealant sealing. The diameter of the waterproof shell of the rolling mechanism is 102mm, and the diameter of the corresponding groove of the shell part is 101.5mm, and the two form an interference fit.

[0045] The flat bearing is located in the bearing groove of the housing, supporting the transmission shaft to transmit power to the tumbling mechanism. The diameter of the transmission shaft is 15mm, and the corresponding hole diameter of the waterproof housing is 15.2mm to avoid friction and extend the service life of the shaft. In order to ensure the tightness of the waterproof protective housing, a double oil seal is added at the shaft hole to prevent ambient water from entering the motor.

[0046] The double oil seal needs to be smeared with a certain amount of grease before mating.

[0047] like Figure 8 As shown, the dual-fin module 2 of the present invention includes an upper fin fixed part 21, an upper fin movable part 212, a lower fin fixed part 221, and a lower fin movable part 222. The fixed part is formed with the corresponding transmission shaft and fixed with bolts. In order to avoid the influence of repeated fin replacement on the service life of the transmission shaft, it is divided into a movable part and a fixed part, and the movable part and the fixed part are fixed by bolts and nuts to form a complete fin.

[0048] To meet the requirements of waterproofing, installation and quality, the drive shaft is made of 6061 aluminum through 3D processing and then polished. The roughness does not exceed 1.5μm. It has the characteristics of high hardness, wear resistance and corrosion resistance.

[0049] like Figure 1 , Figure 2 As shown, the upper shell 11 and the lower shell 12 of the present invention have shapes close to those of a sunfish, and are formed by optimizing the shape of the sunfish. The material is made of gel resin through 3D printing.

[0050] In order to ensure the stability of the connection when the double fins swing at different frequencies, the upper bearing groove 112 and the lower bearing groove 122 are smaller than the outer diameter of the installed bearing, ranging from 0.2 to 0.3 mm, and the retaining springs installed through the bearing limit grooves 113 and 123 further ensure the tightness of the bearing installation.

[0051] The diameter of the shaft hole for installing the upper transmission shaft 31, the lower transmission shaft 32, and the flat transmission shaft 33 is slightly larger than the diameter of the transmission shaft, ranging from 0.2mm to 0.4mm. Before installing the sealing ring, a layer of waterproof sealant should be applied on the inner wall of the sealing ring groove of the upper outer oil seal groove 114 and the lower outer oil seal groove 124. The sealing ring uses a nitrile output shaft sealing ring.

[0052] like Figure 3 , Figure 7 As shown, the planet carrier 54 is slidably connected to the three planetary gears 51 via bearings, so that the distance between the three planetary gears 51 remains relatively stable. The sun gear is rigidly connected to the flat transmission shaft 33 via a coupling and meshes with the three planetary gears 51. The planetary gears 51 also mesh with the gear ring 53.

[0053] The gear meshing part needs to be coated with lubricating oil to reduce noise. The gear ring 53 and the rear waterproof cover 152 are interference fit to fix them.

[0054] The O-type rubber ring and the rear waterproof cover 152 should be fully coated with grease before fitting.

[0055] A control method for an underwater bionic dual-fin robot with a rolling device, wherein a control system 4 controls the rotation of a rolling module to shift the center of gravity of the robot, and controls a transmission module 3 to make the upper and lower fins of the dual-fin module 2 with opposite offset mid-positions swing in opposite directions, and cooperates with a rolling module 5 to make the robot roll up and down. After rolling, the rotation of the rolling module is stopped to stabilize the center of gravity of the robot, and the dual-fin module returns to the zero-degree offset mid-position. Specifically, the method comprises the following steps: Step 1: Put the robot into water and put it in a slightly positive buoyancy state; Step 2: Initialize the dual-fin module 2 by controlling the control system 4 so that the upper and lower fins are at a zero-degree neutral position; Step 3: When the whole robot is in a balanced state, the control system 4 controls the transmission module 3 to drive the upper and lower fins of the double-fin module 2 to swing at a zero-degree offset mid-position, at the same frequency and in the same direction, that is, the phase difference is 0 degrees. At this time, the whole robot is in a linear motion state and maintains a vertical state; Step 4: When the robot performs a rolling action, the control system 4 controls the rolling module 5 to rotate clockwise or counterclockwise. The rotation direction controls the rolling direction of the entire robot. The operation of the rolling module causes the center of gravity originally located below the left and right symmetric center of the robot to shift to the upper left or upper right, gradually tilting from a vertical state to one side of the horizontal plane; Step 5: At the same time, the control system 4 controls the median offset of the upper and lower fins of the dual-fin module 2 to be opposite angles, and the two fins swing in opposite directions, which causes the robot to generate a pulling force outward in the horizontal direction of the two fins, accelerating the speed at which the robot tilts from a vertical state to a horizontal direction, and assisting the robot to complete the rolling action; The opposite angles of the median offsets of the upper and lower fins are within ±10 degrees, and the phase difference of the reverse swings of the double fins is 180 degrees.

[0056] Step 6: After completing the rolling action, the robot flips 90 degrees from its original vertical state to a horizontal state. Fig.11 As shown, the tumbling module is stopped from rotating and its center of gravity is kept in a balanced position, that is, it is rotated 90 degrees from the original 0-degree position. At the same time, the dual-fin module 2 is restored to the zero-degree offset center position, and swings at the same frequency and direction, so that the robot maintains the current motion posture.

[0057] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An underwater bionic dual-fin robot with a tumbling device, comprising a housing (1), a dual-fin module (2), a transmission module (3), a control system (4) and a tumbling module (5), characterized in that: The double fin module (2) is symmetrically mounted at the upper and lower ends of the outer side of the shell (1); the control system (4) causes the center of gravity of the robot to shift via the tumbling module (5), and controls the double fin module (2) via the transmission module (3) to swing the upper and lower double fins in opposite offset positions in the opposite directions, thereby cooperating with the tumbling module (5) to cause the robot to tumble up and down.

2. The underwater bionic double-fin robot with a tumbling device according to claim 1, characterized in that: The transmission module (3) comprises an upper transmission shaft (31), a lower transmission shaft (32) and a flat transmission shaft (33); the dual-fin module (2) comprises an upper fin module (21) and a lower fin module (22); the tumbling module (5) comprises a planetary gear (51), a sun gear (52) and a gear ring (53); the upper transmission shaft (31) is connected to the upper fin module (21); the lower transmission shaft (32) is connected to the lower fin module (22); the sun gear (52) is rigidly connected to the flat transmission shaft (33) via a coupling and meshes with a group of planetary gears (51) surrounding the orbiter; and the group of planetary gears (51) is internally meshed with the gear ring (53).

3. The underwater bionic double-fin robot with a tumbling device according to claim 2, characterized in that: The tumbling module (5) further comprises a planet carrier (54), and the planet carrier (54) is slidably connected to the planetary gear (51) via a bearing.

4. The underwater bionic double-fin robot with a tumbling device according to claim 2, characterized in that: The housing (1) comprises an upper housing (11), a lower housing (12) and a tumbling module waterproof housing (15) arranged symmetrically between the upper and lower housings; the upper housing (11) comprises a flat upper gear ring groove (116), a flat upper tumbling motor groove (117), and a flat upper flat bearing groove (118); the lower housing (12) comprises a flat lower gear ring groove (126), a flat lower tumbling motor groove (127), and a flat lower flat bearing groove (128); the tumbling module waterproof housing (15) comprises a front waterproof cover (151) and a rear waterproof cover (152); the transmission module (3) comprises a flat oil seal (38) and a flat bearing (311); The gear ring groove formed by the upper flat gear ring groove (116) and the lower flat gear ring groove (126) is used to fix the tumbling module waterproof housing (15); the tumbling motor groove formed by the upper flat tumbling motor groove (117) and the lower flat tumbling motor groove (127) is used to fix the tumbling motor; the upper flat bearing groove (118) and the lower flat bearing groove (128) are supported and connected by the flat transmission shaft (33) through the flat bearing (311); The front waterproof cover (151) is provided with a waterproof structure for fixing a flat oil seal (38), a flat transmission shaft (33) and a flat bearing (311); the gear ring (53) and the rear waterproof cover (152) are interference fit, and the flat transmission shaft (33) passes through the front waterproof cover (151) and the flat bearing (311).

5. The underwater bionic double-fin robot with a tumbling device according to claim 2, characterized in that: The upper fin module (21) comprises an upper fin fixed portion (211) and an upper fin movable portion (212); the lower fin module (22) comprises a lower fin fixed portion (221) and a lower fin movable portion (222); the transmission module (3) further comprises an upper outer oil seal (34), an upper inner oil seal (35), a lower outer oil seal (36), a lower inner oil seal (37), an upper bearing (39), and a lower bearing (310); The upper fin fixing portion (211) and the upper fin movable portion (212), the hole of the upper fin fixing portion (211) being arranged in cooperation with the upper transmission shaft (31), the upper transmission shaft (31) passing through the interior of the housing (1) via the upper bearing (39) and passing through the upper outer oil seal (34), the other end of the upper transmission shaft (31) passing through the end surface of the upper inner oil seal (35) inside the housing (1) and being fixed to one end of the motor; The lower fin fixing portion (221) is connected to the lower fin movable portion (222); the hole of the lower fin fixing portion (221) is arranged in cooperation with the lower transmission shaft (32); the lower transmission shaft (32) passes through the interior of the housing (1) via the lower bearing (310) and passes through the lower outer oil seal (36); the other end of the lower transmission shaft (32) passes through the end surface of the lower inner oil seal (37) inside the housing (1) and is fixed to the other end of the motor.

6. The underwater bionic double-fin robot with a tumbling device according to claim 2, characterized in that: The housing (1) comprises an upper housing (11), a lower housing (12) and a motor housing (13) arranged between the upper and lower housings, wherein the motor housing (13) comprises an upper motor housing (131) and a lower motor housing (132); The upper housing (11) comprises an upper motor slot (111), an upper bearing slot (112), an upper bearing limiting slot (113), and an upper outer oil seal slot (114); the lower housing (12) comprises a lower motor slot (121), a lower bearing slot (122), a lower bearing limiting slot (123), and a lower outer oil seal slot (124); The upper motor housing comprises an upper motor housing (1311) and an upper motor lower housing (1312); the lower motor housing (132) comprises a lower motor upper housing (1321) and a lower motor lower housing (1322); the upper motor housing (1311) comprises an upper oil seal groove (13111), an upper spline (13112), an upper inner O-type rubber ring groove (13113), an upper outer O-type rubber ring groove (13114), an upper motor positioning pin (13115), and an upper transmission shaft hole (13116); the upper motor lower housing (1312) comprises an upper wire slot hole (13121), an upper stop groove (13122), and upper and lower splines (13123); the upper motor housing (1311) positions the motor via the upper motor positioning pin (13115); The motor is connected to the bottom of the upper motor lower shell (1312); the outer wall of the upper motor upper shell (1311) is extruded and matched with the motor lower shell (1312) through an O-shaped rubber ring installed in the upper inner O-shaped rubber ring groove (13113); the upper motor upper shell (1311) is fitted with the upper stop groove (13122); the upper transmission shaft (31) passes through the upper transmission shaft hole (13116) and the upper inner oil seal (35) and passes through the upper motor upper shell (1311); the O-shaped rubber ring is sleeved in the upper outer O-shaped rubber ring groove (13114) and squeezes the upper motor groove (111) to form an axial seal; the upper motor groove (111) is connected to the upper motor lower shell (1312) through the upper spline (13112) and the upper and lower splines (13123) and the upper motor upper shell (1311).

7. The underwater bionic double-fin robot with a tumbling device according to claim 2, characterized in that: The housing (1) comprises an upper housing (11), a lower housing (12) and a battery housing (14) arranged between the upper and lower housings, the upper housing (11) comprising a flat upper battery slot (115), the lower housing (12) comprising a flat lower battery slot (125); the battery housing (14) comprising a battery upper housing (141) and a battery lower housing (142); the battery slot formed by the flat upper battery slot (115) and the flat lower battery slot (125) is used to fix an internal battery.

8. A control method for an underwater bionic dual-fin robot with a tumbling device according to any one of claims 1 to 7, characterized in that: The control system (4) controls the rotation of the tumbling module to shift the center of gravity of the robot, and controls the transmission module (3) to make the upper and lower fins of the double fin module (2) with opposite offset mid-positions swing in opposite directions, and cooperates with the tumbling module (5) to make the robot tumble up and down. After tumbling, the tumbling module stops rotating to stabilize the center of gravity of the robot, and at the same time, the double fin module returns to the zero-degree offset mid-position.

9. The control method according to claim 8, characterized in that The specific steps include: Step 1: Put the robot into water and put it in a positive buoyancy state; Step 2: Initialize the dual-fin module (2) by controlling the control system (4) so ​​that the upper and lower fins are at a zero-degree neutral position; Step 3: When in a balanced state, the control system (4) controls the transmission module (3) to drive the upper and lower fins of the double-fin module (2) to swing at a zero-degree offset mid-position, at the same frequency, and in the same direction; Step 4: When the robot performs a rolling action, the control system (4) controls the rolling module (5) to rotate, so that the center of gravity of the robot shifts and gradually tilts from a vertical state to one side of the horizontal plane; Step 5: At the same time, the control system (4) controls the upper and lower fins of the dual-fin module (2) to be offset at opposite angles and to swing in the opposite direction; Step 6: After the robot completes the tumbling action, the tumbling module stops rotating and keeps its center of gravity in a balanced position. At the same time, the dual-fin module (2) returns to the zero-degree offset center position and swings at the same frequency and direction.

10. The control method according to claim 9, characterized in that: In step 5, the median offsets of the upper and lower fins are at opposite angles, and the phase difference of the reverse swings of the two fins is 180 degrees.

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