A high-thrust underwater bionic robot with an asymmetric stiffness swimming arm

Abstract

The present invention discloses a high-propulsion underwater bionic robot with asymmetric stiffness swimming arms, comprising a fairing, a waterproof cabin, a swimming arm and a swimming power device. The fairing is fixedly connected to the waterproof cabin, and a streamlined external design is adopted to reduce water flow resistance; the waterproof cabin comprises a base and a waterproof shell, the base and the waterproof cabin are fixed by bolts and nuts, and O-rings and silicone are used for sealing and waterproofing, and the base carries a buoyancy adjustment device, a center of gravity adjustment device, a power storage device, a load and a control panel. Four swimming arms are symmetrically installed at the bottom of the base, and are driven by the swimming power device to swing back and forth. The power storage device comprises a main power motor, an active turntable, an active block, a screw bearing, and a driven connecting rod, and drives the swimming power device and the swimming arm to move by storing energy and releasing kinetic energy through a spring. The present invention achieves stable and efficient underwater motion performance through innovative mechanical structure and power design, and at the same time has excellent center of gravity adjustment ability and load capacity.

Description

Technical Field

[0001] The present invention relates to the fields of bionics and mechanical structures, and specifically to a bionic jellyfish robot that can achieve attitude changes underwater and has high load capacity and efficient propulsion performance. Background Art

[0002] Bionic robots are a type of artificial intelligence device that mimics the movement patterns and behavioral characteristics of organisms, and they have broad application prospects in fields such as underwater detection, environmental monitoring, and the entertainment industry. The swimming motion of jellyfish mainly includes two stages: diastolic expansion and systolic propulsion. Thrust is generated by quickly closing, and the resistance area is reduced by slowly opening to maintain a stable propulsion effect. In addition, the unique buoyancy adjustment ability of jellyfish enables them to achieve highly flexible vertical movement in water. However, most existing underwater bionic robots mimic the movement mode of jellyfish, but still face many technical challenges when implementing these movements. For example, existing jellyfish bionic robots have the following problems:

[0003] Limited center-of-gravity adjustment ability: Most existing designs adopt simple buoyancy adjustment mechanisms, but it is difficult to achieve precise center-of-gravity adjustment in complex underwater environments, resulting in relatively single attitude control of the robot and affecting the stability and flexibility of movement.

[0004] Slow movement speed: Although the propulsion systems of some existing jellyfish bionic robots mimic the systolic stage of jellyfish, the thrust output in the systolic stage is relatively linear, making it difficult to achieve rapid response and resulting in slow movement speed of the robot.

[0005] Weak load capacity: Many existing bionic jellyfish robots, due to relatively simple functional designs, although they can perform basic movements, are difficult to carry large loads due to limitations of the power system and cannot adapt to complex underwater tasks.

[0006] Based on the above problems, the present invention proposes a bionic jellyfish robot that achieves stable and efficient underwater movement performance through innovative mechanical structures and power designs, and at the same time has excellent center-of-gravity adjustment ability and load capacity. Summary of the Invention

[0007] The purpose of the present invention is to provide a high-thrust underwater bionic robot with asymmetric stiffness swimming arms in view of the deficiencies of the prior art.

[0008] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0009] The present invention includes a fairing, a waterproof cabin, swimming arms, and a swimming power device.

[0010] The fairing is fixedly connected to the waterproof cabin body and has a streamlined external design to reduce water flow resistance; the waterproof cabin body includes a base and a waterproof outer shell, the base and the waterproof outer shell are fixed by bolts and nuts, and are sealed against water by an O-ring and silicone, and bear a buoyancy adjustment device, a center of gravity adjustment device, a power storage and power device, a load and a control board; a plurality of through holes for water inlet are provided on the fairing. There are four swimming arms in total, symmetrically installed at the bottom of the base, and driven by a swimming power device to swing reciprocally. The power storage and power device includes a main power motor, a main turntable, a main stop block, a screw bearing, and a driven connecting rod. The swimming power device and the swimming arms are driven to move by spring energy storage and kinetic energy release.

[0011] The control board is not the key description focus of the structure of the present invention.

[0012] Further, the swimming arm includes: a waterproof servo motor, a first section of the main rigid skeleton, a last section of the main rigid skeleton, a first section of the left rigid skeleton, a last section of the left rigid skeleton, a first section of the right rigid skeleton, a last section of the right rigid skeleton, a flexible material film, a driving gear, and a driven gear. The first section of the main rigid skeleton is connected to the last section of the main rigid skeleton, the first section of the left rigid skeleton is connected to the last section of the left rigid skeleton, and the first section of the right rigid skeleton is connected to the last section of the right rigid skeleton, that is, the corresponding first and last sections of each part of the rigid skeleton are hinged by a stud bearing and can rotate freely.

[0013] Further, the output shaft of the waterproof servo motor of the swimming arm is fixed to the first section of the right rigid skeleton, the protrusion on the first section of the right rigid skeleton is connected to the driving gear, the driving gear meshes with the driven gear, and the driven gear is fixed to the first section of the left rigid skeleton; when the output shaft of the waterproof servo motor rotates, the driving gear drives the driven gear to rotate, so that the left rigid skeleton and the right rigid skeleton rotate synchronously in opposite directions, causing the swimming arm to open and close like a fan. The left rigid skeleton includes the first section of the left rigid skeleton and the last section of the left rigid skeleton, and the right rigid skeleton includes the first section of the right rigid skeleton and the last section of the right rigid skeleton.

[0014] Further, the main transmission rod of the swimming power device moves in the vertical direction, the rod end joint bearing of the swimming power device is fixedly connected to the main transmission rod by a nut, the adjustable double-headed bearing connecting rod is hinged to the main transmission rod by a stud and a bearing, the main transmission rod passes through the hole in the center of the base and moves up and down in the vertical direction, and a spring is installed between the main transmission rod and the base, and a spring is installed between the main transmission rod and the base to provide elastic driving force during the movement.

[0015] Further, a silicone bellows is installed on the main transmission rod, one end of the bellows is fixed and sealed by a pipe clamp, one end is installed at the end of the main transmission rod, and one end is installed on the protrusion below the base, and the installation part is sealed with silicone. When the main transmission rod moves up and down, the bellows moves together with its good stretchability. The internal space of the bellows is connected to the inside of the waterproof cabin body and is a water-free area.

[0016] Furthermore, the main power motor is fixed in the motor mounting groove provided on the base through a bracket. The output shaft of the main power motor is fixedly connected to the driving block. The driving block and the driving turntable are connected through a needle roller bearing, and the two can rotate freely coaxially. The screw bearing is installed on the driving turntable and fixed by a nut. The driving turntable, the driven connecting rod, and the rod end joint bearing are sequentially hinged through studs and bearings; when the driving block rotates, it drives the driving turntable and the driven connecting rod, causing the main transmission rod to move upward, compressing the spring to store energy, and when the spring is released, it drives the swimming arm to quickly paddle through the main transmission rod.

[0017] Furthermore, the swimming arm has an asymmetric stiffness design: a micro spring is connected between the first section and the last section of its rigid skeleton, which is used to adapt to the bending of the water flow to reduce resistance during the slow relaxation stage, and return to a straight state through the spring tension during the fast paddling stage; a limiting structure is also provided between the first section and the last section, which is used to abut against each other during the fast paddling stage, so as to maintain the rigidity of the swimming arm and ensure the propulsion efficiency. The rigid skeleton includes a main rigid skeleton, a left rigid skeleton, and a right rigid skeleton;

[0018] Furthermore, the center of gravity adjustment device includes a counterweight, a gear motor, a rack, a guide rail, a counterweight frame, a guide rail slider, and a pressing strip. The gear motor drives the gear to move linearly along the rack. The counterweight, the gear motor, and the guide rail slider are installed on the counterweight frame for adjusting the center of gravity of the robot, and the guide rail, the rack, and the pressing strip are installed on the base.

[0019] Furthermore, the swimming motion of the robot is divided into three processes: a slow relaxation stage, a fast paddling stage, and a gliding stage. The swimming arm of the robot closes and bends in a fan shape during the slow relaxation stage to reduce resistance; it opens and remains straight in a fan shape during the fast paddling stage to provide a strong thrust; and it remains stationary during the gliding stage to reduce resistance.

[0020] In the slow relaxation stage: the motor rotates to drive the driving block to rotate clockwise. When the driving block contacts the screw bearing, it pushes the screw bearing and the driving turntable to rotate together. Subsequently, the driving block continues to rotate. While driving the driving turntable to rotate, it pulls the main transmission rod upward through the driven connecting rod, compresses the spring, and drives the swimming arm to gradually open through the connecting rod. The swimming arm closes and bends in a fan shape to reduce resistance.

[0021] In the fast paddling stage: when the driving turntable rotates to the highest point, the spring is compressed to the limit, the swimming arm reaches the maximum opening angle, and the fan surface of the swimming arm opens. At this time, the screw bearing disengages from the contact with the driving block, and the elastic potential energy released by the spring provides power to pull the main transmission rod downward, driving the swimming arm to quickly contract while remaining straight, completing the fast paddling stage of swimming. This is the main work process of the robot swimming underwater. When the screw bearing reaches the bottom, the fast paddling stage ends.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. The present invention uses a motor to provide power to compress a spring, store energy in the spring, and then release the spring to quickly release the stored elastic potential energy, providing a large instantaneous power for the swimming arm. This working characteristic brings a high instantaneous thrust to the robot, effectively improving the acceleration and rapid response ability of the robot. At the same time, based on the linear mechanical characteristics of the spring, the thrust distribution is optimized through the spring energy storage and release process, improving the energy utilization rate and propulsion efficiency.

[0024] 2. The asymmetric stiffness design of the swimming arm of the present invention, in cooperation with the flexible film, closes the fan surface and bends to reduce resistance during slow relaxation, and opens the fan surface and keeps it straight to increase thrust during rapid rowing, effectively reducing the influence of the swimming arm resistance on the speed of the robot.

[0025] 3. The robot of the present invention has a large load. The total weight is 11 kg, the load of the center of gravity adjustment device is 1.1 kg, and an additional load of 4.4 kg can be carried. The center of gravity adjustment device can most affect the overall center of gravity of the robot and perform precise attitude control of the inclination of the robot in the horizontal-vertical direction.

[0026] In summary, the present invention solves the problems of low propulsion efficiency and weak load capacity of existing underwater bionic robots. The underwater robot can achieve stable and efficient underwater motion performance and flexible attitude control. Its core technologies include an efficient swimming power device driven by a motor and spring energy storage, an asymmetric stiffness swimming arm, and a large-load center of gravity adjustment device, significantly improving the propulsion efficiency, energy utilization rate, and load capacity. The swimming arm combines a rigid skeleton with a flexible material film and uses a servo motor to achieve three motion states: actively opening, actively closing, and passively bending, optimizing the flexibility and efficiency of the robot's movement. The energy storage power device drives the spring to store energy through a motor and releases the elastic potential energy to provide an instantaneous large thrust for the swimming arm, enhancing the rapid response ability of the robot in water. In addition, the center of gravity adjustment device adjusts the center of gravity of the robot by precisely controlling the movement of the counterweight frame, further improving its attitude control ability. Description of the Drawings

[0027] Figure 1 is a schematic diagram of the overall structure of the present invention.

[0028] Figure 2 is a schematic diagram of the external structure of the swimming arm of the present invention.

[0029] Figure 3 is a schematic diagram of the transmission structure of the swimming arm of the present invention.

[0030] Figure 4 is a schematic diagram of the bending structure of the swimming arm of the present invention.

[0031] Figure 5 It is a schematic diagram of the center-of-gravity adjustment device and the internal structure in the present invention.

[0032] Figure 6 It is a schematic diagram of the overall inclination of the center-of-gravity adjustment device of the present invention.

[0033] Figure 7 It is a schematic diagram of the distribution of the internal devices in the cabin body of the present invention.

[0034] Figure 8 It is a schematic diagram of the structures of the swimming power device and the energy storage power device in the present invention. Specific embodiments

[0035] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0036] As Figure 1 shown, the present invention provides a high-thrust underwater bionic robot with asymmetric stiffness swimming arms, including a fairing 1, a waterproof cabin body 2, a buoyancy adjustment device 5, a center-of-gravity adjustment device 6, an energy storage power device 7, a swimming power device 4, and swimming arms 3. The robot can efficiently complete bionic motion, buoyancy and center-of-gravity adjustment, and flexible direction control. Its core technologies include an efficient energy storage system based on spring drive, a large-load center-of-gravity adjustment device with remarkable effects, and an asymmetric stiffness swimming arm design, which significantly improves the propulsion efficiency and energy utilization rate.

[0037] The fairing 1 and the waterproof cabin body 2 are installed together and adopt a streamlined design, which can effectively reduce the water flow resistance. The buoyancy adjustment device 5, the center-of-gravity adjustment device 6 and the electronic control module are installed inside the waterproof cabin body 2, and the waterproof cabin body 2 provides waterproof protection and load support;

[0038] The center-of-gravity adjustment device 6 uses a gear-rack drive as the core drive system. The gear motor 62 drives the rotation of the gear meshing with the rack 63, so as to realize the linear motion of the counterweight frame 65 along the guide rail 64. This drive method has high rigidity and precision, can maintain stable center-of-gravity adjustment under different working conditions, and at the same time ensures the tight combination of the gear-rack mechanism and the guide rail 64 through the pressing strip 67 to improve the structural stability. The counterweight frame 65 is fixed to the counterweight block 61 and installed on the guide rail slider 66, and the guide rail 64 provides the constraint and guidance for the movement, ensuring that the counterweight frame 65 can still move smoothly when carrying a large load.

[0039] The energy storage power device 7 drives a linkage system through a motor to store energy for the spring 43 of the swimming power device 4. The two together provide power for the swimming arm 3 to simulate the diastolic and systolic movements of jellyfish. The swimming drive arm is composed of a rigid skeleton and a flexible material film 37, and a servo motor is combined to realize the switching of three motion states (actively opening, actively closing, and passively bending), thereby effectively improving the propulsion efficiency and motion flexibility.

[0040] As Figure 1 shown, the fairing 1 and the waterproof housing 22 are formed by 3D printing with high-strength white resin. The two are fixedly installed together to form a streamlined external contour, which can effectively reduce the water flow resistance. The space between the fairing 1 and the waterproof housing 22 is the immersion area, where an immersion counterweight is placed. The immersion counterweight is 1.8 kg and is designed as a replaceable module. The counterweight object should be symmetrical, and its weight can be adjusted within the range of 1.5 - 2.0 kg to adapt to different load requirements. Multiple regularly arranged drainage holes are attached to both sides of the fairing 1 to ensure its connection with the external water environment.

[0041] As Figure 2 shown, each swimming arm 3 includes a waterproof servo motor 30, a main rigid skeleton, a left rigid skeleton, a right rigid skeleton, a flexible material film 37, a driving gear 38, and a driven gear 39. The main rigid skeleton includes a main rigid skeleton head section 31 and a main rigid skeleton tail section 32; the left rigid skeleton includes a left rigid skeleton head section 33 and a left rigid skeleton tail section 34; the right rigid skeleton includes a right rigid skeleton head section 35 and a right rigid skeleton tail section 36. The skeletons are all formed by 3D printing with high-strength resin. The corresponding head and tail sections of each part of the rigid skeleton are hinged through stud bearings and can rotate freely.

[0042] The fairing 1 adopts a streamlined body of revolution design and selects the Granville line type in the streamline curve cluster method line type. It is overall streamlined and has good hydrodynamic performance. This design can effectively reduce the resistance of water flow and improve the motion efficiency of the robot. Multiple drainage holes that can let water in and out are provided on the fairing 1 to balance the water level height inside and outside the fairing 1.

[0043] As Figure 3As shown, the output shaft of the waterproof servo 30 is fixed to the driving gear 38 and the first section 35 of the right rigid frame, and the driven gear 39 is fixed to the first section 33 of the left rigid frame. When the output shaft of the waterproof servo 30 rotates, the main rigid frame does not move, and the driving gear 38 drives the driven gear 39 to rotate, so that the left rigid frame and the right rigid frame rotate synchronously in opposite directions, so that the swimming arm 3 fan is opened. At the same time, four synchronous connecting rods, two long and two short, are installed on the left and right frames of the swimming arm 3, which are hinged by bolts and bearings. The other end of the connecting rod is also installed on the micro guide slider 66 of the main frame by bolts and bearings. The rotation of the right rigid frame will drive the slider to move up and down on the guide rail 64, and synchronously drive the connecting rod on the other side and the driven frame to rotate, helping the fan to open and close synchronously better and increase the structural stability.

[0044] A flexible material film 37 is installed between the frames of the swimming arm 3 and fixed on both sides by bolts and nuts. When the fan is closed, the film will be retracted and clamped between the frames, and will not increase the resistance of the swimming arm 3. When the fan is opened, the flexible material film 37 is opened and tightened, which can increase the resistance of the swimming arm 3.

[0045] like Figure 4 As shown, the swimming arm 3 has asymmetric stiffness, and a micro spring is connected between the first and last sections of the rigid skeleton of the swimming arm 3, and both ends of the spring are fixed at Figure 4 When the swimming arm 3 accumulates power and slowly relaxes, the lower part of the swimming arm 3 bends under the action of water flow resistance to reduce the resistance received, and the spring is stretched at this time. When the power accumulation stage ends, the swimming arm 3 reaches the highest point, and the swimming arm 3 returns to a straight state under the action of the spring tension.

[0046] The swimming arm 3 needs greater rigidity when it contracts quickly to paddle, and a limited position structure is designed at the connection between the first and the last end of the skeleton, such as Figure 4 As shown in the dotted circle on the right side, they can resist each other when subjected to force, so that the other side of the swimming arm 3 will not bend when subjected to force, and will remain straight, ensuring that the swimming thrust will not be reduced.

[0047] The asymmetric stiffness design of the swimming arm 3 reduces water resistance by bending the lower part during the slow relaxation phase, thereby improving movement efficiency; while during the fast paddling phase, the rigidity is maintained through the limiting structure, ensuring sufficient propulsion force, significantly improving propulsion efficiency and stability, and is more in line with bionic motion characteristics than traditional designs.

[0048] like Figure 5As shown, the gear of the gear motor 62 of the center of gravity adjustment device 6 is meshed with the rack 63, and the driving force is provided by the rotation of the gear, and the directional constraint is provided by the guide rail slider 66 installed on the counterweight frame 65 moving on the guide rail 64. Because the load of the counterweight frame 65 is relatively large, in order to prevent the counterweight frame 65 from being deformed due to excessive load and affecting the meshing of the gear rack, the movement trajectory of the load frame is further limited by the clamping strip 67 to ensure the close connection between the gear and the rack 63 and improve the stability of the structure. The buffer block is set at the extreme position of the counterweight frame 65. When the counterweight frame 65 moves to the end of the stroke, it can effectively absorb kinetic energy to prevent the counterweight from impacting and damaging the base plate. As shown Figure 6 As shown, the center of gravity adjustment device is tilted 10° as a whole. This tilt design can significantly increase the adjustment range of the center of gravity, thereby making the center of gravity change more flexible and the adjustment effect of the device more significant.

[0049] like Figure 7 As shown, a power storage device 7 is installed on the base 21, which includes a main power motor 71, a driving turntable 72, a driving block 73, a screw bearing 74, and a driven connecting rod 75. The main power motor 71 is fixed in the designed motor mounting groove on the base 21 through a bracket, and the output shaft of the main power motor 71 is fixedly connected to the active block 73. The active block 73 is connected to the driving turntable 72 through a needle bearing, and the two can rotate freely coaxially. The screw bearing 74 is installed on the driving turntable 72 and fixed by a nut. The driving turntable 72, the driven connecting rod 75, and the rod end joint bearing 41 are hinged in sequence through studs and bearings. The driving turntable 72 and the driven connecting rod 75 are formed by 3D printing of high-strength white resin. The active block 73 is made of metal material due to the high working intensity required.

[0050] The base 21 is formed by 3D printing of high-strength and high-toughness black resin, and is fixed to the waterproof shell 22 with screws and nuts. Both the base 21 and the waterproof shell 22 have two circles of O-ring installation grooves for placing O-rings, and some silicone with a hardness of 10 degrees is added and tightened with bolts to ensure sealing performance.

[0051] The base 21 is equipped with a depth sensor and a waterproof switch. When a problem occurs, the power can be cut off manually underwater to protect the robot. Two small holes are also opened to place the power line and signal line of the waterproof servo 30. The waterproof servos 30 are grouped in pairs, and each group uses one hole. After the wires pass through, they are sealed with silicone to ensure waterproof performance, and a layer of hot melt adhesive is covered on both surfaces of the silicone to increase strength.

[0052] A limit base is installed below the base 21 to provide end limit for the swimming arm 3, ensuring that the swimming arm 3 will not contract inward excessively due to inertia at the end of the rapid contraction stage, causing problems of interference and collision between the swimming arms 3. Four swimming arms 3 are symmetrically installed at the bottom of the base 21 and are hinged through bearings and copper columns, and the swimming arms 3 can rotate freely.

[0053] To reduce friction, a flat thrust needle bearing and a gasket are installed between the driving turntable 72 and the driven connecting rod 75, which can also play a role in adjusting flatness.

[0054] The buoyancy device 5 uses a lead screw motor as the power source and drives the sealing piston to reciprocate through a flange and a connecting rod. Through this design, the buoyancy device can realize the operations of pumping water and draining water, thereby adjusting the buoyancy of the robot;

[0055] As Figure 8 shown, the rod end joint bearing 41 of the swimming power device 4 is fixedly connected to the main transmission rod 42 through a nut, the adjustable double-end bearing connecting rod 44 is hinged to the main transmission rod 42 through a stud and a bearing, the main transmission rod 42 moves up and down in the vertical direction through the hole in the center of the base 21, and the spring 43 is installed between the main transmission rod 42 and the base 21.

[0056] The adjustable double-end bearing connecting rod 44 consists of a right-hand thread rod end bearing, a left-hand thread rod end bearing and a threaded rod. By rotating the threaded rod, the overall length of the double-end bearing connecting rod 44 can be changed, which is used to adjust the working stroke range of the swimming arm 3.

[0057] A silica gel bellows is installed on the main transmission rod 42. One end of the bellows is fixedly sealed through a pipe clamp, one end is installed at the end of the main transmission rod 42, and one end is installed on the protrusion below the base 21, and the installation part is sealed with silica gel. When the main transmission rod 42 moves up and down, the bellows moves together relying on its good stretchability. The internal space of the bellows is connected to the inside of the waterproof cabin 2 and is a water-free area.

[0058] The swimming motion of the robot is divided into three processes: slow diastolic stage, rapid stroke stage and gliding stage.

[0059] In the slow diastolic stage, the energy storage power device 7 works. The driving motor 71 drives the driving block 73 to rotate clockwise. When the driving block 73 contacts the screw bearing 74, it pushes the screw bearing 74 and the driving turntable 72 to rotate together. Subsequently, the driving block 73 continues to rotate. While driving the driving turntable 72 to rotate, it pulls the main transmission rod 42 upward through the driven connecting rod 75, compresses the spring, and drives the swimming arm 3 to gradually open through the adjustable double-end bearing connecting rod 44.

[0060] Based on the linear mechanical characteristics of the spring 43, the stage with a larger elastic force of the spring 43 coincides with the stage with the largest projected area during the water - paddling process of the swimming arm 3, while the part with a smaller elastic force of the spring 43 coincides with the stage with a smaller projected area during the water - paddling process of the swimming arm 3. Generally speaking, the proportion of useful work is increased, and the swimming efficiency and energy utilization rate are improved.

[0061] During the fast - paddling stage, it starts when the active turntable 72 rotates to the highest point. At this time, the spring 43 is compressed to the limit, and the swimming arm 3 reaches the maximum opening angle. The screw bearing 74 disengages from the contact with the active rotating block, and the elastic potential energy released by the spring 43 provides power to pull the main transmission rod 42 downward, driving the rapid contraction of the swimming arm 3 to complete the fast - paddling stage of swimming. This is the main work - doing process of the robot swimming underwater. When the screw bearing 74 reaches the bottom, the fast - paddling stage ends.

[0062] Subsequently, the robot enters the gliding stage, and the system enters the standby state, waiting for the active block 73 driven by the motor to complete the remaining half - circle rotation stroke. After that, the swimming power device returns to the initial state, preparing to enter the next action cycle.

[0063] When steering is required, the fan - shaped surface of the swimming arm 3 on the side close to the steering direction always remains closed, reducing the propulsion force, making the propulsion force on this side decrease, and generating a rotational torque. After the robot completes the turn, the swimming arm 3 resumes normal operation and moves forward in the new direction.

[0064] The control of the robot body uses a single - chip microcomputer of model STM32f407ZGT6 to control the motor power supply through a relay, which serves as a power - off protection unit during operation failures, and controls the total power supply of the robot through a waterproof switch. Integrate the wireless serial port module ATK - LORA, the gyroscope MPU6050, and the depth sensor. The wireless serial port module communicates wirelessly with the upper computer, and realizes the remote real - time control of the robot's direction, depth, and propulsion force through wireless communication.

[0065] Experimental data: The whole bionic jellyfish robot weighs about 11 kg, with a total counterweight of 5.5 kg. The maximum diameter of the cabin is 240 mm, the height of the waterproof cabin 2 is 270 mm, the length of the cabin 1 with a fairing is 400 mm, and the total length of the robot is 740 mm. It is independently powered by a 24V lithium - ion battery with a capacity of 6000 mAh, without external signal lines and power lines. The test site is a small pool with a length of 4 meters and a width of 2 meters, and the water depth is 1 meter. When testing, the gliding time of the robot is set to 1 second, and a complete motion cycle is about 2.3 seconds. Among them, the opening process of the swimming arm 3 takes about 0.8 seconds, and the speed is relatively slow during this stage, with an average speed of 10 cm / s. The paddling process of the swimming arm 3 takes about 0.5 seconds, and the gliding process takes 1 second. The average speed during this stage is 25 - 30 cm / s. On average, the overall speed is about 20 - 23 cm / s.

Claims

1. A high-thrust underwater bionic robot with an asymmetric stiffness swimming arm, characterized by including: A fairing (1), a waterproof cabin (2), a swimming arm (3) and a swimming power device (4); The deflector (1) is fixedly connected to the waterproof cabin (2) and adopts a streamlined external design to reduce water flow resistance; the waterproof cabin (2) comprises a base (21) and a waterproof shell (22); the base (21) and the waterproof shell (22) are fixed by bolts and nuts, and are sealed with O-rings and silicone for waterproofing, and carry a buoyancy adjustment device (5), a center of gravity adjustment device (6), a power storage device (7), a load and a control panel; There are four swimming arms (3) in total, which are symmetrically mounted on the bottom of the base (21) and driven by the swimming power device (4) to swing back and forth; The power storage device (7) comprises a main power motor (71), a main rotating disk (72), a main stopper (73), a screw bearing (74), and a driven connecting rod (75); the swimming power device (4) and the swimming arm (3) are driven to move by storing energy and releasing kinetic energy through a spring (43); The swimming arm (3) comprises: a waterproof steering gear (30), a main rigid frame first section (31), a main rigid frame last section (32), a left rigid frame first section (33), a left rigid frame last section (34), a right rigid frame first section (35), a right rigid frame last section (36), a flexible material film (37), a driving gear (38), and a driven gear (39); the main rigid frame first section (31) and the main rigid frame last section (32), the left rigid frame first section (33) and the left rigid frame last section (34), and the right rigid frame first section (35) and the right rigid frame last section (36) are respectively connected, that is, the first and last sections corresponding to each part of the rigid frame are hinged through stud bearings and can rotate freely; The waterproof steering gear output shaft of the swimming arm (3) is fixed to the right rigid frame first section (35), the protrusion on the right rigid frame first section (35) is connected to the driving gear (38), the driving gear (38) is meshed with the driven gear (39), and the driven gear (39) is fixed to the left rigid frame first section (33); when the waterproof steering gear output shaft rotates, the driving gear (38) drives the driven gear (39) to rotate, so that the left rigid frame and the right rigid frame rotate synchronously in opposite directions, so that the swimming arm fan surface opens and closes; the left rigid frame includes the left rigid frame first section (33) and the left rigid frame last section (34), and the right rigid frame includes the right rigid frame first section (35) and the right rigid frame last section (36).

2. The high-thrust underwater bionic robot with asymmetric stiffness swimming arms according to claim 1, characterized in that: The main transmission rod (42) of the swimming power device (4) moves in the vertical direction, the rod end joint bearing (41) of the swimming power device (4) is fixedly connected to the main transmission rod (42) through a nut, the adjustable double-head bearing connecting rod (44) is hinged to the main transmission rod (42) through a stud and a bearing, the main transmission rod (42) passes through a hole in the center of the base (21) and moves up and down in the vertical direction, a spring is installed between the main transmission rod (42) and the base (21), and a spring (43) is installed between the main transmission rod (42) and the base (21) to provide an elastic driving force during the movement.

3. The high-thrust underwater bionic robot with an asymmetric stiffness swimming arm according to claim 2, characterized in that: A silicone bellows is installed on the main transmission rod (42). One end of the bellows is fixed and sealed by a pipe clamp and installed at the end of the main transmission rod (42), and the other end is installed on the protrusion under the base (21), and the installation part is sealed with silicone. When the main transmission rod (42) moves up and down, the bellows moves together relying on its good flexibility. The internal space of the bellows is connected to the inside of the waterproof cabin (2), which is a water-free area.

4. The high-thrust underwater bionic robot with asymmetric stiffness swimming arms according to claim 3, characterized in that, The main power motor (71) is fixed on the base (21) through a bracket in the designed motor installation groove. The output shaft of the main power motor (71) is fixedly connected to the active stopper (73). The active stopper (73) and the active turntable (72) are connected by a needle bearing, and the two can rotate freely coaxially. The screw bearing (74) is installed on the active turntable (72) and fixed by a nut. The active turntable (72), the driven connecting rod (75), and the rod end spherical bearing (41) are successively hinged by studs and bearings. When the active stopper (73) rotates, it drives the active turntable and the driven connecting rod (75), making the main transmission rod (42) move upward, compressing the spring (43) to store energy. When the spring (43) is released, it drives the swimming arm (3) to quickly paddle through the main transmission rod (42).

5. The high-thrust underwater bionic robot with an asymmetric stiffness swimming arm according to claim 4, characterized in that The swimming arm (3) has an asymmetric stiffness design: A micro spring is connected between the first section and the last section of its rigid skeleton, which is used to close and bend the fan surface during the slow diastolic phase to reduce resistance, and to restore the fan surface to open and keep straight through the spring tension during the quick paddling phase to provide a strong thrust; A limiting structure is also arranged between the first section and the last section, which is used to abut against each other during the quick paddling phase, so as to maintain the rigidity of the swimming arm (3).

6. The high-thrust underwater bionic robot with an asymmetric stiffness swimming arm according to claim 5, characterized in that, The center of gravity adjustment device (6) includes a counterweight (61), a gear motor (62), a rack (63), a guide rail (64), a counterweight frame (65), a guide rail slider (66) and a pressing strip (67). The gear motor (62) drives the gear to move linearly along the rack (63). The counterweight (61), the gear motor (62) and the guide rail slider (66) are installed on the counterweight frame (65) for adjusting the center of gravity of the robot. The guide rail (64), the rack (63) and the pressing strip (67) are installed on the base (21).

7. The high-thrust underwater bionic robot with asymmetric stiffness swimming arms according to claim 6, characterized in that, In the slow diastolic phase: The motor rotates to drive the active stopper (73) to rotate clockwise. When the active stopper (73) contacts the screw bearing (74), it pushes the screw bearing (74) and the active turntable (72) to rotate together. Subsequently, the active stopper (73) continues to rotate. While driving the active turntable (72) to rotate, it pulls the main transmission rod (42) upward through the driven connecting rod (75), compresses the spring (43), and drives the swimming arm (3) to gradually open through the connecting rod. The fan surface of the swimming arm (3) closes and bends to reduce resistance.

8. The high-thrust underwater bionic robot with an asymmetric stiffness swimming arm according to claim 7, characterized in that, The described rapid stroke stage: When the active turntable (72) rotates to the highest point, the spring (43) is compressed to the limit, the swimming arm (3) reaches the maximum opening angle, and the fan-shaped surface of the swimming arm (3) opens; at this time, the screw bearing (74) disengages from the contact with the active rotating block, and the elastic potential energy released by the spring (43) provides power to pull down the main transmission rod (42) and drive the swimming arm (3) to quickly contract while maintaining a straight state, completing the rapid stroke stage of swimming. This is the main work process of the robot swimming underwater; when the screw bearing (74) reaches the bottom, the rapid stroke stage ends.

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