Bionic underwater robot based on long wave motion propulsion principle of MPF

Abstract

The application provides a bionic underwater robot based on MPF long-wave motion propulsion principle, which comprises a front-end propulsion mechanism for generating front-end propulsion force, a central pitching mechanism for adjusting the pitching pose of the robot, a middle-end propulsion mechanism for generating middle-end propulsion force, a tail-end motor driving mechanism for providing overall driving, and a robot control system; the front end of the front-end propulsion mechanism is connected with the front end of the central pitching mechanism, the tail end of the central pitching mechanism is connected with the front end of the middle-end propulsion mechanism, the tail end of the middle-end propulsion mechanism is connected with the front end of the tail-end motor driving mechanism, and the robot control system is connected with the central pitching mechanism and the tail-end motor driving mechanism and outputs control instructions. The application achieves the purposes of simple structure, easy assembly, low energy consumption and cost reduction; in addition, the pitching motion of the underwater robot is realized by relying on the change of the shape instead of the displacement, and the space utilization and underwater swimming performance are improved.

Description

Technical Field

[0001] This invention relates to the field of robot application technology, specifically to a biomimetic underwater robot based on the MPF long-wave motion propulsion principle. Background Technology

[0002] Given the increasing depletion of terrestrial resources and space, the exploration and development of marine resources has become a hot topic, and underwater propulsion devices and robots adapted to the marine working environment have become a research focus for scientists worldwide. Bionic underwater robots are robots designed to operate in aquatic environments, mimicking the swimming patterns and propulsion methods of aquatic organisms. Abundant aquatic biological resources provide rich inspiration for the movement patterns, operation strategies, pressure resistance, and drag reduction designs of bionic underwater robots.

[0003] The propulsion principles of biomimetic underwater robots are divided into two types: BCF (body / tail fin propulsion) and MPF (central fin / pair fin propulsion). Biomimetic underwater robots based on the MPF long-wave propulsion principle have advantages such as high maneuverability, strong anti-interference ability, and excellent environmental friendliness. Therefore, the research on this type of biomimetic underwater robot has a very broad market prospect and application value.

[0004] Patent document CN113428329A (application number: CN202110776831.8) discloses an underwater robot with a propulsion system similar to that of a batfish. This device includes a pressure-resistant cabin, servo motors, and flexible fins. The underwater robot's interior contains a center-of-gravity adjustment mechanism, a control module, a camera, a support plate, and a battery module. The pressure-resistant cabin consists of a shell and end caps. The servo motors are symmetrically arranged on both sides of the cabin's central axis, with five motors on each side. Each servo motor has aluminum fins for connecting to the flexible fins. There are two flexible fins, each connected to one of the servo motors. The fins deform flexibly as they oscillate. When there is an initial phase difference between the servo motors and they reciprocate, the fins transmit sinusoidal motion to the flexible fins, and the traveling wave propagates along the surface of the flexible fins, generating thrust. However, this patent does not meet the requirements of this invention. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a biomimetic underwater robot based on the MPF long-wave motion propulsion principle.

[0006] The biomimetic underwater robot based on the MPF long-wave motion propulsion principle provided by the present invention includes: a front propulsion mechanism for generating front thrust, a central pitch mechanism for adjusting the robot's pitch posture, a mid-end propulsion mechanism for generating mid-end thrust, an end motor drive mechanism for providing overall drive, and a robot control system.

[0007] The end of the front propulsion mechanism is connected to the front of the central pitch mechanism, the end of the central pitch mechanism is connected to the front of the middle propulsion mechanism, the end of the middle propulsion mechanism is connected to the front of the end motor drive mechanism, and the robot control system is connected to the central pitch mechanism and the end motor drive mechanism and outputs control commands.

[0008] Preferably, the front-end propulsion mechanism includes: a first transmission propulsion unit, a second transmission propulsion unit, a first front-end fin shaft, a second front-end fin shaft, a first front-end main shaft, a second front-end main shaft, and a first transmission frame sheet metal part;

[0009] The first and second front-end fin shafts pass through the first and second transmission propulsion units and are fixed in axial position by sleeves; the first and second front-end main shafts pass through the first and second transmission propulsion units and are connected to the gear system of the transmission propulsion unit by pins; the front side of the first transmission frame sheet metal part is connected to the end side of the first transmission propulsion unit, and the end side of the first transmission frame sheet metal part is connected to the front side of the second transmission propulsion unit.

[0010] Preferably, the mid-end propulsion mechanism includes: a third transmission propulsion unit, a fourth transmission propulsion unit, a fifth transmission propulsion unit, a second transmission frame sheet metal part, a third transmission frame sheet metal part, a first rear end fin shaft, a second rear end fin shaft, a first rear end main shaft, and a second rear end main shaft;

[0011] The first and second rear fin shafts pass through the third, fourth, and fifth transmission propulsion units, connecting them and fixing their axial positions with sleeves. The first and second rear main shafts pass through the third, fourth, and fifth transmission propulsion units and are connected to the gear train of the transmission propulsion units by pins. The front side of the second transmission frame sheet metal part is bolted to the rear side of the third transmission propulsion unit, and the rear side of the second transmission frame sheet metal part is bolted to the front side of the fourth transmission propulsion unit. The front side of the third transmission frame sheet metal part is bolted to the rear side of the fourth transmission propulsion unit, and the rear side of the third transmission frame sheet metal part is bolted to the front side of the fifth transmission propulsion unit.

[0012] Preferably, the central pitch mechanism includes: a first pitch fixing frame, a second pitch fixing frame, a first universal joint, a second universal joint, a first pitch frame sheet metal part, a second pitch frame sheet metal part, and a pitch transmission assembly;

[0013] The front side of the pitch transmission assembly is bolted to the first pitch fixing frame, and the rear side of the pitch transmission assembly is bolted to the second pitch fixing frame. The front end of the first universal joint is pinned to the first front main shaft passing through the first pitch fixing frame, and the rear end of the first universal joint is pinned to the first rear main shaft passing through the second pitch fixing frame. The front end of the second universal joint is pinned to the second front main shaft passing through the first pitch fixing frame, and the rear end of the second universal joint is pinned to the second rear main shaft passing through the second pitch fixing frame. The front side of the first pitch frame sheet metal is bolted to the rear side of the second transmission propulsion unit, and the rear side of the first pitch frame sheet metal is bolted to the front side of the first pitch fixing frame. The front side of the second pitch frame sheet metal is bolted to the rear side of the second pitch fixing frame, and the rear side of the second pitch frame sheet metal is bolted to the front side of the mid-end propulsion mechanism.

[0014] Preferably, the end motor drive mechanism includes: a first coupling, a second coupling, a first waterproof motor, a second waterproof motor, a motor support, an end motor frame, and a motor frame sheet metal part;

[0015] The front end of the first coupling is connected to the first rear main shaft, and the end of the first coupling is connected to the first waterproof motor shaft; the front end of the second coupling is connected to the second rear main shaft, and the end of the second coupling is connected to the second waterproof motor shaft; the front side of the motor frame sheet metal part is bolted to the end side of the fifth transmission propulsion unit, and the end side of the motor frame sheet metal part is connected to the front side of the end motor frame; the first waterproof motor and the second waterproof motor pass through the motor support and the end motor frame, the front end shaft of the first waterproof motor is connected to the first coupling, and the front end shaft of the second waterproof motor is connected to the second coupling.

[0016] Preferably, the transmission propulsion unit includes a first transmission propulsion unit, a second transmission propulsion unit, a third transmission propulsion unit, a fourth transmission propulsion unit, and a fifth transmission propulsion unit;

[0017] The spindle includes a first front spindle, a second front spindle, a first rear spindle, and a second rear spindle;

[0018] The fin shaft includes a first front fin shaft, a second front fin shaft, a first rear fin shaft, and a second rear fin shaft;

[0019] The transmission propulsion unit has a symmetrical structure and includes: a transmission propulsion frame, a gear train, bearings, a short shaft, a crank, a connecting rod, and fins;

[0020] The main shaft passes through the bearing, the transmission and propulsion frame, and the inner gear of the gear system in sequence, and is connected to the inner gear of the gear system by a pin; the short shaft passes through the crank, the bearing, the transmission and propulsion frame, and the outer gear of the gear system in sequence, and is connected to the crank and the outer gear of the gear system by a pin; one end of the connecting rod is connected to the small hole of the crank, and the other end of the connecting rod is connected to the inner hole of the fin. The fin is sleeved on the fin shaft through the middle hole and the axial position is fixed by a sleeve.

[0021] Preferably, the pitch transmission assembly includes: an upper waterproof servo, a lower waterproof servo, left and right pitch transmission linkage pairs, left and right pitch main rods, a front lug, and a rear lug.

[0022] The upper and lower waterproof servos are each bolted to the left and right sides of the left and right pitch transmission linkage pairs. The other end of the left and right pitch transmission linkage pairs is bolted to the middle of the corresponding left and right pitch main rods. One side of the left and right pitch main rods is bolted to the end lug, and the slot on the other side of the left and right pitch main rods is bolted to the front lug.

[0023] Preferably, the robot control system includes a motor drive control module and a servo motor drive control module;

[0024] The control modules for the first waterproof motor, the second waterproof motor, the upper waterproof servo motor, and the lower waterproof servo motor are independent of each other. The motor drive control module sends control signals to control the motor speed, and the servo motor drive control module sends control signals to control the servo motor angle, thereby controlling the robot's movement.

[0025] Preferably, the robot's motion propulsion mechanism is as follows: flexible silicone is continuously coated on the fin surface to form a flexible fin surface, and the motion waveform is set by adjusting the initial phase of the fin in the transmission propulsion unit during installation;

[0026] The specific operation method is as follows: When assembling the inner and outer gears of the gear system, each tooth of the outer gear is labeled. Two adjacent outer gears are assembled sequentially with a certain number of teeth interval, thereby creating a certain phase difference between the positions of adjacent fins, which in turn forms a set waveform for propelling the robot's movement. The first waterproof motor and the second waterproof motor are controlled to rotate forward at the same speed, generating a waveform that propagates backward, thus generating a forward thrust, and the robot completes the forward movement. The first waterproof motor and the second waterproof motor are controlled to rotate in opposite directions at the same speed, generating a waveform that propagates forward, thus generating a backward thrust, and the robot completes the backward movement.

[0027] Preferably, the robot's turning mechanism is as follows: by differentiating the rotation speeds of the two waterproof motors, the wave speeds of the left and right fins are made different, thereby generating a difference in the left and right propulsion forces, thus completing the robot's turning action. Specifically, when the rotation speed of the right motor is greater than that of the left motor, the robot completes the action of turning to the left; when the rotation speed of the right motor is less than that of the left motor, the robot completes the action of turning to the right.

[0028] The mechanism of the robot's pitch motion is as follows: the upper waterproof servo and the lower waterproof servo adjust the servo shaft angle in the same direction, and drive the left and right pitch main rods to rotate through the left and right pitch transmission linkages, thereby transmitting the servo torque to the front end, causing the robot's front end to rotate around the first universal joint and the second universal joint, thus completing the pitch posture adjustment action.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] This invention solves the problems of high motor requirements, high energy consumption, complex control modules, and high costs caused by single motor driving a single fin in the prior art. It establishes a single motor driving a multi-fin structure, achieving the goals of simple structure, easy assembly, low energy consumption, and reduced cost. In addition, this invention achieves the pitch motion of the underwater robot by changing its own shape rather than changing its displacement, thus improving space utilization and underwater mobility. Attached Figure Description

[0031] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0032] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0033] Figure 2 This is a schematic diagram of the front-end propulsion mechanism of the present invention;

[0034] Figure 3 This is a schematic diagram of the central pitch mechanism of the present invention;

[0035] Figure 4 This is a schematic diagram of the mid-range propulsion mechanism of the present invention;

[0036] Figure 5 This is a schematic diagram of the end motor drive mechanism of the present invention;

[0037] Figure 6 This is a schematic diagram of the transmission and propulsion unit structure of the present invention;

[0038] Figure 7 This is a schematic diagram of the complete design of the present invention;

[0039] In the diagram: 1. Front-end propulsion mechanism; 2. Central pitch mechanism; 3. Mid-end propulsion mechanism; 4. End-end motor drive mechanism; 5. First transmission propulsion unit; 6. Second transmission propulsion unit; 7. First front-end fin shaft; 8. Second front-end fin shaft; 9. First front-end main shaft; 10. Second front-end main shaft; 11. First transmission frame sheet metal part; 12. First pitch fixing frame; 13. Second pitch fixing frame; 14. First universal joint; 15. Second universal joint; 16. First pitch frame sheet metal part; 17. Second pitch frame sheet metal part; 18. Pitch transmission assembly; 19. Third transmission propulsion unit; 20. Fourth transmission propulsion unit; 21. Fifth transmission propulsion unit; 22. Second transmission frame sheet metal part. 23. Third transmission frame sheet metal part, 24. First rear end fin shaft, 25. Second rear end fin shaft, 26. First rear end main shaft, 27. Second rear end main shaft, 28. First coupling, 29. Second coupling, 30. First waterproof motor, 31. Second waterproof motor, 32. Motor support part, 33. End motor frame, 34. Motor frame sheet metal part, 35. Front housing, 36. Rear housing, 37. Transmission propulsion frame, 38. Gear system, 39. Bearing, 40. Short shaft, 41. Crank, 42. Connecting rod, 43. Fin, 44. Upper waterproof servo, 45. Lower waterproof servo, 46. Left and right pitch transmission connecting rod pair, 47. Left and right pitch main rod, 48. Front lug, 49. End lug. Detailed Implementation

[0040] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0041] Example:

[0042] like Figure 1 This invention provides a biomimetic underwater robot based on the MPF (Multi-wavelength propulsion) principle, comprising: a front-end propulsion mechanism 1 for generating front-end propulsion, a central pitch mechanism 2 for adjusting the robot's pitch posture, a mid-end propulsion mechanism 3 for generating mid-end propulsion, an end-effector motor drive mechanism 4 for providing overall drive, and a robot control system. The end of the front-end propulsion mechanism 1 is connected to the front end of the central pitch mechanism 2; the end of the central pitch mechanism 2 is connected to the front end of the mid-end propulsion mechanism 3; the end of the mid-end propulsion mechanism 3 is connected to the front end of the end-effector motor drive mechanism 4; and the robot control system is connected to the central pitch mechanism 2 and the end-effector motor drive mechanism 4 and outputs control commands. Figure 7 The front shell 35 and the rear shell 36 are used to enclose the front and rear ends of the biomimetic underwater robot.

[0043] like Figure 2The front-end propulsion mechanism 1 includes: a first transmission propulsion unit 5, a second transmission propulsion unit 6, a first front-end fin shaft 7, a second front-end fin shaft 8, a first front-end main shaft 9, a second front-end main shaft 10, and a first transmission frame sheet metal part 11. The first front-end fin shaft 7 and the second front-end fin shaft 8 pass through the first transmission propulsion unit 5 and the second transmission propulsion unit 6 and are fixed in axial position by sleeves. The first front-end main shaft 9 and the second front-end main shaft 10 pass through the first transmission propulsion unit 5 and the second transmission propulsion unit 6 and are connected to the gear system of the transmission propulsion unit by pins. The front side of the first transmission frame sheet metal part 11 is connected to the end side of the first transmission propulsion unit 5, and the end side is connected to the front side of the second transmission propulsion unit 6.

[0044] like Figure 3 The central pitch mechanism 2 includes: a first pitch fixing frame 12, a second pitch fixing frame 13, a first universal joint 14, a second universal joint 15, a first pitch frame sheet metal part 16, a second pitch frame sheet metal part 17, and a pitch transmission assembly 18. The pitch transmission assembly 18 is bolted to the front of the first pitch fixing frame 12 and bolted to the rear of the second pitch fixing frame 13. The front end 14 of the first universal joint is pinned to the first front main shaft 9 passing through the first pitch fixing frame 12, and the rear end is pinned to the second pitch fixing frame 13. The first rear end spindle 26 of the frame 13 is connected by a pin. The front end of the second universal joint 15 is connected by a pin to the second front end spindle 10 passing through the first pitch fixing frame 12, and the end is connected by a pin to the second rear end spindle 27 passing through the second pitch fixing frame 13. The front side of the first pitch frame sheet metal part 16 is bolted to the end side of the second transmission propulsion unit 6, and the end side is bolted to the front side of the first pitch fixing frame. The front side of the second pitch frame sheet metal part 17 is bolted to the end side of the second pitch fixing frame 13, and the end side is bolted to the front side of the middle propulsion mechanism 3.

[0045] like Figure 4The mid-range propulsion mechanism 3 includes: a third transmission propulsion unit 19, a fourth transmission propulsion unit 20, a fifth transmission propulsion unit 21, a second transmission frame sheet metal part 22, a third transmission frame sheet metal part 23, a first rear end fin shaft 24, a second rear end fin shaft 25, a first rear end main shaft 26, and a second rear end main shaft 27. The first rear end fin shaft 24 and the second rear end fin shaft 25 pass through the third transmission propulsion unit 19, the fourth transmission propulsion unit 20, and the fifth transmission propulsion unit 21, connecting the three and fixing their axial positions with sleeves. The first rear-end main shaft 26 and the second rear-end main shaft 27 pass through the third transmission propulsion unit 19, the fourth transmission propulsion unit 20, and the fifth transmission propulsion unit 21, and are connected to the gear system of the transmission propulsion unit by pins. The front side of the second transmission frame sheet metal part 22 is bolted to the rear side of the third transmission propulsion unit 19, and the rear side is bolted to the front side of the fourth transmission propulsion unit 20. The front side of the third transmission frame sheet metal part 23 is bolted to the rear side of the fourth transmission propulsion unit 20, and the rear side is bolted to the front side of the fifth transmission propulsion unit 21.

[0046] like Figure 5 The end motor drive mechanism 4 includes: a first coupling 28, a second coupling 29, a first waterproof motor 30, a second waterproof motor 31, a motor support 32, an end motor frame 33, and a motor frame sheet metal part 34. The front end of the first coupling 28 is connected to the first rear main shaft 26, and the end is connected to the shaft of the first waterproof motor 30. The front end of the second coupling 29 is connected to the second rear main shaft 27, and the end is connected to the shaft of the second waterproof motor 31. The front side of the motor frame sheet metal part 34 is bolted to the end side of the fifth transmission propulsion unit 21, and the end side is connected to the front side of the end motor frame 33. The first waterproof motor 30 and the second waterproof motor 31 pass through the motor support 32 and the end motor frame 33, and their front end shafts are connected to the coupling.

[0047] like Figure 6 The transmission propulsion unit (5-6, 19-21) includes: a transmission propulsion frame 37, a gear train 38, a bearing 39, a short shaft 40, a crank 41, a connecting rod 42, and a fin 43. The transmission propulsion unit (5-6, 19-21) has a symmetrical structure. The main shaft (9-10, 26-27) passes through the bearing 39, the transmission propulsion frame 37, and the inner gear of the gear train 38 in sequence, and is connected to the inner gear of the gear train 38 by a pin. The short shaft 40 passes through the crank 41, the bearing 39, the transmission propulsion frame 37, and the outer gear of the gear train 38 in sequence, and is connected to the crank 41 and the outer gear of the gear train 38 by a pin. One end of the connecting rod 42 is connected to the small hole of the crank 41, and the other end is connected to the inner hole of the fin 43. The fin 43 is sleeved on the fin shaft (7-8, 24-25) through the middle hole and its axial position is fixed by a sleeve.

[0048] The pitch transmission assembly 18 includes: an upper waterproof servo 44, a lower waterproof servo 45, left and right pitch transmission linkage pairs 46, left and right pitch main rods 47, a front lug 48, and a rear lug 49. The left and right sides of the upper and lower waterproof servos 44 are each bolted to the left and right sides of the pitch transmission linkage pairs 46. The other end of the pitch transmission linkage 46 is bolted to the middle of the corresponding pitch main rod 47. One side of the left and right pitch main rod 47 is bolted to the rear lug 49, and the slot on the other side is bolted to the front lug 48.

[0049] The robot control system includes a motor drive control module and a servo drive control module. The control modules for the first waterproof motor 30, the second waterproof motor 31, the upper waterproof servo motor 44, and the lower waterproof servo motor 45 are independent of each other. The motor drive control module sends control signals to control the speed of the motors, and the servo drive control module sends control signals to control the rotation angle of the servo motors, thereby controlling the movement of the robot.

[0050] Work methods:

[0051] Combination Figure 1 The robot's motion propulsion mechanism is explained as follows: The robot's motion is designed based on the MPF long-wave propulsion principle. Flexible silicone is continuously coated onto the fin surfaces to form flexible fin surfaces. During installation, the initial phase of the fins 43 in each transmission propulsion unit (5-6, 19-21) is adjusted to set the motion waveform. Specifically, when assembling the inner and outer gears of the gear system 38, each tooth of the outer gear is labeled. Two adjacent outer gears are assembled sequentially with a certain number of teeth interval, thereby creating a certain phase difference between the positions of adjacent fins 43, thus forming the set waveform for propulsion of the robot. Controlling the first waterproof motor 30 and the second waterproof motor 31 to rotate forward at the same speed generates a waveform that propagates backward, thereby generating forward propulsion force, and the robot completes the forward motion. Similarly, controlling the first waterproof motor 30 and the second waterproof motor 31 to rotate in opposite directions at the same speed generates a waveform that propagates forward, thereby generating backward propulsion force, and the robot completes the backward motion.

[0052] Combination Figure 1 The turning mechanism of the robot is explained as follows: Scientific research on MPF ​​propulsion shows that the higher the wave speed of the fin waveform, the greater the propulsive force generated. The robot proposed here differentiates the rotation speeds of the two waterproof motors, causing a difference in the wave speeds of the left and right fins, thereby generating a difference in the left and right propulsive forces, thus completing the robot's turning motion. Specifically, when the rotation speed of the right motor is greater than that of the left motor, the robot turns left; when the rotation speed of the right motor is less than that of the left motor, the robot turns right.

[0053] Combination Figure 3 The mechanism of the robot's pitch motion is explained as follows: The upper waterproof servo motor 44 and the lower waterproof servo motor 45 adjust the servo motor shaft angle in the same direction. Through the left and right pitch transmission linkages 46, the left and right pitch main rods 47 are rotated, thereby transmitting the servo motor torque to the front end, causing the robot's front end to rotate around the first universal joint 14 and the second universal joint 15 as the center, thus completing the pitch posture adjustment action.

[0054] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0055] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A biomimetic underwater robot based on the MPF long-wave motion propulsion principle, characterized in that, include: A front-end propulsion mechanism (1) for generating front-end thrust, a central pitch mechanism (2) for adjusting the robot's pitch posture, a mid-end propulsion mechanism (3) for generating mid-end thrust, an end motor drive mechanism (4) for providing overall drive, and a robot control system. The end of the front propulsion mechanism (1) is connected to the front end of the central pitch mechanism (2), the end of the central pitch mechanism (2) is connected to the front end of the middle propulsion mechanism (3), the end of the middle propulsion mechanism (3) is connected to the front end of the end motor drive mechanism (4), and the robot control system is connected to the central pitch mechanism (2) and the end motor drive mechanism (4) and outputs control commands. The front-end propulsion mechanism (1) includes: a first transmission propulsion unit (5), a second transmission propulsion unit (6), a first front-end fin shaft (7), a second front-end fin shaft (8), a first front-end main shaft (9), a second front-end main shaft (10), and a first transmission frame sheet metal part (11). The first front fin shaft (7) and the second front fin shaft (8) pass through the first transmission propulsion unit (5) and the second transmission propulsion unit (6) and are fixed in axial position with sleeves; the first front main shaft (9) and the second front main shaft (10) pass through the first transmission propulsion unit (5) and the second transmission propulsion unit (6) and are connected to the gear system of the transmission propulsion unit with pins; the front side of the first transmission frame sheet metal part (11) is connected to the end side of the first transmission propulsion unit (5) and the end side of the first transmission frame sheet metal part (11) is connected to the front side of the second transmission propulsion unit (6); The mid-end propulsion mechanism (3) includes: a third transmission propulsion unit (19), a fourth transmission propulsion unit (20), a fifth transmission propulsion unit (21), a second transmission frame sheet metal part (22), a third transmission frame sheet metal part (23), a first rear end fin shaft (24), a second rear end fin shaft (25), a first rear end main shaft (26), and a second rear end main shaft (27). The first rear fin shaft (24) and the second rear fin shaft (25) pass through the third transmission propulsion unit (19), the fourth transmission propulsion unit (20), and the fifth transmission propulsion unit (21) to connect the three and fix their axial positions with a sleeve; the first rear main shaft (26) and the second rear main shaft (27) pass through the third transmission propulsion unit (19), the fourth transmission propulsion unit (20), and the fifth transmission propulsion unit (21) and are connected to the gear system of the transmission propulsion unit by a pin; the front side of the second transmission frame sheet metal part (22) is bolted to the end side of the third transmission propulsion unit (19), and the end side of the second transmission frame sheet metal part (22) is bolted to the front side of the fourth transmission propulsion unit (20); the front side of the third transmission frame sheet metal part (23) is bolted to the end side of the fourth transmission propulsion unit (20), and the end side of the third transmission frame sheet metal part (23) is bolted to the front side of the fifth transmission propulsion unit (21); The central pitch mechanism (2) includes: a first pitch fixing frame (12), a second pitch fixing frame (13), a first universal joint (14), a second universal joint (15), a first pitch frame sheet metal part (16), a second pitch frame sheet metal part (17), and a pitch transmission assembly (18). The front side of the pitch drive assembly (18) is bolted to the first pitch fixing frame (12), and the rear side of the pitch drive assembly (18) is bolted to the second pitch fixing frame (13); the front end of the first universal joint (14) is pinned to the first front end spindle (9) passing through the first pitch fixing frame (12), and the rear end of the first universal joint (14) is pinned to the first rear end spindle (26) passing through the second pitch fixing frame (13); the front end of the second universal joint (15) is pinned to the second front end spindle (10) passing through the first pitch fixing frame (12). The end of the second universal joint (15) is connected to the second rear spindle (27) passing through the second pitch fixing frame (13) by a pin; the front side of the first pitch frame sheet metal part (16) is connected to the end side of the second transmission propulsion unit (6) by bolts, and the end side of the first pitch frame sheet metal part (16) is connected to the front side of the first pitch fixing frame (12) by bolts; the front side of the second pitch frame sheet metal part (17) is connected to the end side of the second pitch fixing frame (13) by bolts, and the end side of the second pitch frame sheet metal part (17) is connected to the front side of the middle propulsion mechanism (3) by bolts; The pitch transmission assembly (18) includes: an upper waterproof servo (44), a lower waterproof servo (45), left and right pitch transmission linkage pairs (46), left and right pitch main rods (47), a front lug (48), and a rear lug (49). The upper waterproof servo (44) and the lower waterproof servo (45) are each bolted to the left and right sides of the left and right pitch transmission linkage pair (46). The other end of the left and right pitch transmission linkage pair (46) is bolted to the middle of the corresponding left and right pitch main rod (47). One side of the left and right pitch main rod (47) is bolted to the end lug (49), and the slot on the other side of the left and right pitch main rod (47) is bolted to the front lug (48).

2. The biomimetic underwater robot based on the MPF long-wave motion propulsion principle according to claim 1, characterized in that, The end motor drive mechanism (4) includes: a first coupling (28), a second coupling (29), a first waterproof motor (30), a second waterproof motor (31), a motor support (32), an end motor frame (33), and a motor frame sheet metal part (34). The front end of the first coupling (28) is connected to the first rear main shaft (26), and the end of the first coupling (28) is connected to the shaft of the first waterproof motor (30); the front end of the second coupling (29) is connected to the second rear main shaft (27), and the end of the second coupling (29) is connected to the shaft of the second waterproof motor (31); the front side of the motor frame sheet metal part (34) is bolted to the end side of the fifth transmission propulsion unit (21), and the end side of the motor frame sheet metal part (34) is connected to the front side of the end motor frame (33); the first waterproof motor (30) and the second waterproof motor (31) pass through the motor support part (32) and the end motor frame (33), the front end shaft of the first waterproof motor (30) is connected to the first coupling (28), and the front end shaft of the second waterproof motor (31) is connected to the second coupling (29).

3. The biomimetic underwater robot based on the MPF long-wave motion propulsion principle according to claim 2, characterized in that, The transmission propulsion unit includes a first transmission propulsion unit (5), a second transmission propulsion unit (6), a third transmission propulsion unit (19), a fourth transmission propulsion unit (20), and a fifth transmission propulsion unit (21). The spindle includes a first front spindle (9), a second front spindle (10), a first rear spindle (26), and a second rear spindle (27); The fin shaft includes a first front fin shaft (7), a second front fin shaft (8), a first rear fin shaft (24), and a second rear fin shaft (25); The transmission propulsion unit has a symmetrical structure and includes: a transmission propulsion frame (37), a gear system (38), a bearing (39), a short shaft (40), a crank (41), a connecting rod (42), and fins (43). The main shaft passes through the bearing (39), the transmission propulsion frame (37), and the inner gear of the gear system (38) in sequence, and is connected to the inner gear of the gear system (38) by a pin; the short shaft (40) passes through the crank (41), the bearing (39), the transmission propulsion frame (37), and the outer gear of the gear system (38) in sequence, and is connected to the crank (41) and the outer gear of the gear system (38) by a pin; one end of the connecting rod (42) is connected to the small hole of the crank (41), and the other end of the connecting rod (42) is connected to the inner hole of the fin (43). The fin (43) is sleeved on the fin shaft through the middle hole and the axial position is fixed by a sleeve.

4. The biomimetic underwater robot based on the MPF long-wave motion propulsion principle according to claim 3, characterized in that, The robot control system includes a motor drive control module and a servo motor drive control module; The control modules of the first waterproof motor (30), the second waterproof motor (31), the upper waterproof servo motor (44), and the lower waterproof servo motor (45) are independent of each other. The motor drive control module sends control signals to control the speed of the motor, and the servo motor drive control module sends control signals to control the rotation angle of the servo motor, thereby controlling the movement of the robot.

5. The biomimetic underwater robot based on the MPF long-wave motion propulsion principle according to claim 4, characterized in that, The robot's motion propulsion mechanism is as follows: flexible silicone is continuously coated on the fin surface to form a flexible fin surface. During installation, the motion waveform is set by adjusting the initial phase of the fin (43) in the transmission propulsion unit. The specific operation method is as follows: When assembling the inner and outer gears of the gear system (38), each tooth of the outer gear is labeled. The two adjacent outer gears are assembled in sequence with a certain number of teeth interval, so that the positions of the adjacent fins (43) are sequentially formed with a certain phase difference, so that the fin surface forms a set waveform for propelling the robot's movement; control the first waterproof motor (30) and the second waterproof motor (31) to rotate in the forward direction at the same speed, generating a waveform that propagates backward, thereby generating a forward thrust, and the robot completes the forward movement; control the first waterproof motor (30) and the second waterproof motor (31) to rotate in the opposite direction at the same speed, generating a waveform that propagates forward, thereby generating a backward thrust, and the robot completes the backward movement.

6. The biomimetic underwater robot based on the MPF long-wave motion propulsion principle according to claim 5, characterized in that, The robot's turning mechanism is as follows: by differentiating the rotation speeds of the two waterproof motors, the wave speeds of the left and right fins differ, resulting in a difference in the left and right propulsion forces, thereby completing the robot's turning motion. Specifically, when the rotation speed of the right motor is greater than that of the left motor, the robot turns to the left; when the rotation speed of the right motor is less than that of the left motor, the robot turns to the right. The mechanism of the robot's pitch action is as follows: the upper waterproof servo motor (44) and the lower waterproof servo motor (45) adjust the servo motor shaft angle in the same direction, and drive the left and right pitch main rods (47) to rotate through the left and right pitch transmission linkages (46), thereby transmitting the servo motor torque to the front end, driving the robot's front end to rotate around the first universal joint (14) and the second universal joint (15) as the center, and completing the pitch posture adjustment action.

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