Three-degree-of-freedom multifunctional transmission mechanism for underwater robot and working method

Abstract

The invention relates to a three-degree-of-freedom multifunctional transmission mechanism for an underwater robot and a working method, and belongs to the technical field of bathyscapes. The three-degree-of-freedom multifunctional transmission mechanism comprises a stay wire transmission unit, an energy conversion unit and a structure supporting unit; the structure supporting unit is used for supporting the whole mechanism; the stay wire transmission unit is used for realizing three-degree-of-freedom motion of pitching, yawing and rolling; and the energy conversion unit is used for meeting two functional requirements of energy capture and driving control. The rigidity of the joint is adjustable by improving the stay wire transmission unit, three-degree-of-freedom movement of pitching, yawing and rolling is achieved in combination with gear transmission, and the two functional requirements of energy capture and driving control are met at the same time through magnetic coupling transmission; and internal parts are protected from seawater corrosion through an anti-aging rubber corrugated pipe and a seawater vulcanized rubber sealing process.

Description

Technical Field

[0001] This invention relates to a three-degree-of-freedom multifunctional transmission mechanism and its working method for underwater robots, belonging to the field of deep-sea submersible technology. Background Technology

[0002] Jointed underwater robots play a crucial role in marine exploration, underwater construction, and inspection tasks due to their superior maneuverability and flexibility. Traditional jointed underwater robots often employ direct-drive gearboxes or hydraulic oscillating cylinders for their transmission mechanisms, resulting in large distal masses, lengthy sealing components, and high system rotational inertia. This leads to an excessively large turning radius, limiting their maneuverability in complex seabed environments. While traditional rigid transmission systems offer high structural rigidity and excellent positioning accuracy, their inherent low compliance limits performance in dynamic interactive tasks. When subjected to external impact loads or subjected to high-precision force control, these systems often exhibit significant rigidity and lack effective passive energy buffering mechanisms. This characteristic easily induces large contact stresses, increasing the risk of mechanical damage to the system itself and the manipulated objects.

[0003] Northeastern University invented a two-degree-of-freedom joint structure (application number 201710571402), which achieves pitch and rotational motion through a single motor drive. However, its structure is relatively complex, employing a three-stage gear reduction design, increasing the difficulty of installation and maintenance. The Shanghai Aerospace Systems Engineering Research Institute invented a two-degree-of-freedom joint for space robots (application number 201510302614), achieving pitch, rotation, and their combined motion by adjusting the motor's speed and angle. However, its structure is complex, and its size and weight remain relatively large, making it difficult to meet the lightweight requirements of underwater robots. Tianjin University invented a two-degree-of-freedom joint for deep-sea multi-jointed submersibles (application number 201910628038), using two orthogonally mounted motors. Tongji University invented an underwater robot joint (application number 202410335554), using bevel gear transmission; both achieve pitch and yaw motion for a single joint. Nanjing Institute of Technology invented a three-degree-of-freedom biomimetic turtle robot (application number 202310387491), which uses a planetary gear differential structure and a rotary mechanism to achieve three degrees of freedom movement of the flippers. However, these designs still maintain a rigid structure, which has weak resistance to ocean current impacts and is prone to damage to internal parts. Northeast Petroleum University invented a three-drive active ball joint underwater snake robot (application number: 202421152828), in which the ball joint module achieves flexible movement of three degrees of freedom through servo motors and gear transmission. However, the three-drive system requires three servo motors to be controlled separately and to achieve precise synchronization, resulting in a complex structure and high control difficulty. Xinxing Jihua (Beijing) Intelligent Equipment Technology Research Institute Co., Ltd. invented a three-degree-of-freedom joint, robotic arm and robot (application number 202422087420), which achieves rolling, pitching and yaw movements through a swivel joint and a universal joint. In addition, it uses a line drive to reduce the mass of the joint and reduce inertia by placing the motor at the rear. However, the joint stiffness is fixed and cannot adapt to complex marine environments. Rope-driven transmission technology transmits force and motion through flexible ropes, and concentrates the drive motors in a pressure-resistant chamber, making the joint body lightweight and compact. It is considered an ideal solution for building long-torso, multi-jointed robots.

[0004] Existing multi-joint underwater robot joints have the following shortcomings:

[0005] (1) Most of them are rigid structures, which have a weak ability to resist the impact of ocean currents and lack sufficient flexibility to absorb external disturbance energy. They are prone to vibration and positioning deviation in strong ocean current environments, which in turn affects the stability of operations.

[0006] (2) The joint stiffness is fixed and cannot adapt to complex marine environments;

[0007] (3) The drive unit is mainly concentrated in the joint area, which leads to a complex sealing structure and a high system rotational inertia, affecting the flexibility of movement;

[0008] (4) The energy supply relies on portable batteries, making it difficult to achieve long-term continuous operation, and it fails to effectively utilize the kinetic energy in the underwater environment for energy replenishment. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention proposes a three-degree-of-freedom multifunctional transmission mechanism and its working method for underwater robots. By improving the cable transmission unit, the joint stiffness is made adjustable, and combined with gear transmission, it realizes three degrees of freedom of movement: pitch, yaw, and roll. Through magnetic coupling transmission, it simultaneously meets the functional requirements of energy harvesting and drive control. The internal components are protected from seawater corrosion by aging-resistant rubber bellows and seawater-grade vulcanized sealant.

[0010] The present invention adopts the following technical solution:

[0011] A three-degree-of-freedom multifunctional transmission mechanism for underwater robots includes a wire transmission unit, an energy conversion unit, and a structural support unit;

[0012] The structural support unit is used to support the entire mechanism; the cable drive unit is used to realize the three degrees of freedom of movement: pitch, yaw and roll; the energy conversion unit is used to meet the two functional requirements of energy capture and drive control.

[0013] Preferably, the cable drive unit includes a yaw disc A, a yaw disc B, a drive rope A, a drive rope B, a yaw shaft, a hydraulic cylinder, a low-speed motor, a gear pump, an oil tank, an electromagnetic reversing valve, a valve block, a magnetic coupler A, a guide wheel A, a guide wheel B, a pitch shaft, a pitch shaft bracket, a winding shaft A, and a winding shaft B.

[0014] The structural support unit includes an end cap, a joint support, an upper cabin end cap, a lower cabin end cap, a gear bracket, a motor bracket, and a bellows.

[0015] There are two pitch axis supports, each fixedly connected to one side of the end cap. The two ends of the pitch axis are movably connected to the pitch axis supports. Guide wheels A and B are located at both ends of the pitch axis, allowing the pitch axis to rotate together with guide wheels A and B. The rear end clasp of the hydraulic cylinder is sleeved with the middle of the pitch axis, and the front end clasp is sleeved with the middle of the yaw axis. The hydraulic cylinder can rotate relative to the pitch axis and yaw axis respectively. The pitch axis and yaw axis are perpendicular to each other in opposite planes.

[0016] The yaw disk A and yaw disk B are respectively movably mounted at both ends of the yaw axis, and yaw disk A and yaw disk B can rotate relative to the yaw axis; the yaw disk A is fixedly connected to the end cover of the upper hull, driving the next section of the hull to rotate, thereby realizing pitch or yaw motion.

[0017] Preferably, the oil tank and low-speed motor are fixedly installed inside the upper hull end cover, the low-speed motor is coaxially connected to the input end of the magnetic coupler A, the gear pump is fixedly installed outside the upper hull end cover and coaxially connected to the output end of the magnetic coupler A, the valve block is fixedly installed outside the upper hull end cover, and the electromagnetic reversing valve is fixedly connected to the valve block.

[0018] Preferably, the energy conversion unit includes a reducer, a magnetic coupler B, gear A, gear B, gear C, gear D, an internal gear, an electromagnetic clutch A, an electromagnetic clutch B, an electric motor, a generator, a storage battery, and a geared motor.

[0019] The reducer is fixedly installed on the other side of the end cover. The reducer has a dual-shaft output with the two output shafts arranged opposite each other. The input shaft of the reducer is perpendicular to the two output shafts. The winding shaft A and the winding shaft B are respectively connected to the two output shafts of the reducer and are parallel to the guide wheel A and the guide wheel B respectively. The input shaft of the reducer is coaxially connected to the output end of the magnetic coupler B.

[0020] Gear A is coaxially connected to the input end of magnetic coupler B. Gear B meshes with gear A and is coaxially connected to the output end of electromagnetic clutch A. The input end of electromagnetic clutch A is connected to a motor. Gear C meshes with gear A and is coaxially connected to the input end of electromagnetic clutch B. The output end of electromagnetic clutch B is connected to a generator. Gear B and gear C do not contact each other. Gear D is coaxially connected to a reduction motor. Gear D meshes with an internal gear. The internal gear is fixedly installed inside the lower hull end cover, driving the lower hull end cover to rotate around the axis to achieve rolling motion. Gear D and the internal gear do not contact gear A, gear B, or gear C.

[0021] Preferably, a joint support is provided between the end cover and the lower hull end cover, gears A, B, C, and D are installed on one side of the gear bracket, electromagnetic clutches A and B and a reduction motor are fixedly installed on the other side of the gear bracket, the gear bracket is fixedly connected to the motor bracket, the generator, motor and battery are fixedly installed on the motor bracket, and the motor bracket is fixedly connected to the hull shell.

[0022] When gear A rotates, it drives the input shaft of magnetic coupler B to rotate synchronously. By changing the magnetic field distribution inside magnetic coupler B, the torque is transmitted to the output shaft of magnetic coupler B, which in turn drives the input shaft of the reducer to rotate, thus realizing non-contact power transmission. The low-speed motor and the gear pump also achieve non-contact power transmission through magnetic coupler A. Combined with the upper and lower chamber end covers with sealed end caps, the sealing separation between the chamber and the joint is ensured, effectively improving the reliability of the internal sealing of the chamber.

[0023] Preferably, guide grooves are provided on the outer surfaces of yaw disk A, yaw disk B, guide wheel A, and guide wheel B, guide wheel A and guide wheel B are provided with two guide grooves (inner and outer), and yaw disk A and yaw disk B are provided with one guide groove.

[0024] Spiral guide grooves are provided on the outer surfaces of winding shaft A and winding shaft B. The spiral guide grooves of the two winding shafts rotate in opposite directions. The transmission rope A / transmission rope B moves in the guide grooves to prevent the transmission rope from slipping or tangling during the movement.

[0025] The transmission rope A is wound around the winding shaft A, and a screw is set to fix the two turns of transmission rope in the middle to prevent the transmission rope from slipping and axial movement during operation, and to ensure winding stability. One outer end of the transmission rope A is wound and riveted to the yaw disc A after passing through the outer guide groove of the guide wheel A, and the other inner end of the transmission rope A is wound onto the yaw disc B after passing through the inner guide groove of the guide wheel A.

[0026] The transmission rope B is wound around the winding shaft B, and a screw is used to fix the two turns of transmission rope in the middle. The outer end of the transmission rope B is wound and riveted to the yaw disc A after passing through the outer guide groove of the guide wheel B. The inner end of the transmission rope B is wound around the yaw disc B after passing through the inner guide groove of the guide wheel B, and is connected to the inner end of the transmission rope A.

[0027] Preferably, both transmission rope A and transmission rope B are made of steel wire rope.

[0028] Preferably, the hydraulic cylinder can change the distance between the yaw axis and the pitch axis, thereby adjusting the tension of the transmission rope and making the joint stiffness variable; when high stiffness is required (such as for precision operation or energy capture), the hydraulic cylinder extends to increase the tension of the transmission rope; when high compliance is required (such as for shock absorption or resistance to strong currents), the hydraulic cylinder shortens to reduce the tension of the transmission rope; the low-speed motor drives the gear pump through the magnetic coupler A, thereby controlling the hydraulic oil to enter the valve block from the oil tank, and adjusting the extension and retraction of the hydraulic cylinder piston rod under the action of the electromagnetic reversing valve.

[0029] Preferably, the upper and lower hull end caps are sealed together by an aging-resistant rubber bellows, and the connection is sealed with marine-grade vulcanized rubber, which achieves joint sealing while ensuring the flexibility of the joint during multi-degree-of-freedom movement.

[0030] A method for operating the aforementioned three-degree-of-freedom multifunctional transmission mechanism for underwater robots includes a drive control mode and an energy harvesting mode.

[0031] In drive control mode, the battery provides energy to the motor, and the motor transmits power to gear B through electromagnetic clutch A. At this time, electromagnetic clutch B is in the disengaged state, the generator does not participate in the transmission process, gear B meshes with gear A, so that the power is transmitted to the input shaft of the reducer through magnetic coupler B, and then distributed to the winding shaft A and winding shaft B respectively through the two output shafts of the reducer, thereby driving the transmission rope A and transmission rope B to move.

[0032] When the winding shafts A and B rotate in the same direction under the drive of the reducer output shaft, the outer ends of the transmission ropes A and B extend / retract, and the inner ends retract / extend, thereby driving the yaw disc A, yaw disc B, yaw shaft, and hydraulic cylinder to rotate around the pitch axis, thus realizing the pitch movement of the joint; when the winding shafts A and B rotate in opposite directions, the outer ends of the transmission ropes A extend / retract, and the inner ends retract / extend, and the outer ends of the transmission ropes B retract / extend, and the inner ends extend / retract, thus driving the yaw disc A to rotate around the yaw axis, thereby realizing the yaw movement of the joint.

[0033] In addition, the battery can also power the geared motor, which transmits power to gear D. Gear D meshes with the internal gear, thereby driving the end cover of the cabin to rotate and realize the rolling motion of the joint.

[0034] In energy capture mode, the hull oscillates with the waves, and the change in the volume of displaced water causes buoyancy fluctuations. When the hull is lifted to the wave crest, the volume of displaced water decreases, resulting in buoyancy less than gravity, generating a downward resultant force. Conversely, when the hull sinks to the wave trough, the volume of displaced water increases, and buoyancy greater than gravity, creating an upward resultant force. This buoyancy difference drives the hull to oscillate. Due to the phase difference in the oscillation motion of the hulls on both sides of the joint, the hulls on both sides of the joint sway vertically under the constraint of the joint, which in turn causes the joint to pitch. The horizontal forward and backward motion of water particles generates huge thrust and pull on the hull, and the propagating waves create a phase difference in the longitudinal motion of the underwater robot. This phase difference generates a recurring torque at the joint, converting the horizontal input of wave energy into a coordinated serpentine oscillation of the underwater robot in the horizontal plane, which in turn triggers the yaw motion of the joint. The pitch and yaw motion of the joint drives the yaw disk A to rotate. Through the linkage of transmission rope A and transmission rope B, the winding shaft A and winding shaft B rotate accordingly. The rotational power of winding shaft A and winding shaft B is transmitted to the magnetic coupler B through the reducer, which drives gear A to rotate. Gear A meshes with gear C, so that the power is transmitted to the generator through the electromagnetic clutch B. At this time, the electromagnetic clutch A is in the open state, the motor does not participate in the operation, and the generator converts mechanical energy into electrical energy and stores it in the battery, thereby realizing energy recovery.

[0035] For any details not covered in this invention, please refer to the prior art.

[0036] The beneficial effects of this invention are as follows:

[0037] (1) The present invention adopts rope drive transmission and has adjustable stiffness, which can absorb and buffer impact energy, resist strong current, enhance the flexibility of underwater robot, reduce the risk of mechanical damage, and also achieve precise control, improve operation accuracy and energy capture efficiency.

[0038] (2) The present invention can realize three degrees of freedom of motion in one joint, namely pitch, yaw and roll, which improves the flexibility of underwater robots and is suitable for complex marine environments.

[0039] (3) The present invention uses aging-resistant rubber corrugated pipe for joint protection, enhances external flexibility, and protects internal components from seawater corrosion and foreign matter entanglement. Marine vulcanized rubber sealing process is implemented to achieve secondary protection.

[0040] (4) The present invention provides a sealed end cap for the cabin and uses a magnetic coupler to achieve a sealed separation between the cabin and the joint, preventing seawater from leaking into the cabin due to joint seal failure, and ensuring the safety and reliability of the internal components of the cabin.

[0041] (5) The energy conversion unit of the present invention integrates charging and discharging modes, and combines energy capture and drive control functions, effectively saving space and significantly improving battery life. Attached Figure Description

[0042] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0043] Figure 1 This is an external structural diagram of a three-degree-of-freedom multifunctional transmission mechanism for underwater robots.

[0044] Figure 2 This is an overall structural diagram of a three-degree-of-freedom multifunctional transmission mechanism for underwater robots.

[0045] Figure 3 This is an internal structural diagram of a three-degree-of-freedom multifunctional transmission mechanism for underwater robots.

[0046] Figure 4 This is a schematic diagram of the yaw disk A winding of a three-degree-of-freedom multifunctional transmission mechanism for an underwater robot.

[0047] Figure 5 This is a schematic diagram of the winding of a winding shaft for a three-degree-of-freedom multifunctional transmission mechanism used in underwater robots.

[0048] Figure 6This is a flowchart illustrating the pitch and yaw motion of a three-degree-of-freedom multifunctional transmission mechanism for an underwater robot.

[0049] Figure 7 This is a schematic diagram of the pitch motion of a three-degree-of-freedom multifunctional transmission mechanism for underwater robots.

[0050] Figure 8 This is a schematic diagram of the yaw motion of a three-degree-of-freedom multifunctional transmission mechanism for underwater robots.

[0051] Among them, 1-oil tank, 2-low speed motor, 3-upper hull end cover, 4-magnetic coupler A, 5-gear pump, 6-valve block, 7-solenoid directional valve, 8-yaw disc A, 9-yaw disc B, 10-yaw shaft, 11-drive rope A, 12-drive rope B, 13-cylinder, 14-guide wheel A, 15-guide wheel B, 16-pitch shaft, 17-pitch shaft bracket, 18-end cover, 19-winding shaft A, 20-winding wire Shaft B, 21-Joint support, 22-Reducer, 23-Lower hull end cover, 24-Magnetic coupler B, 25-Internal gear, 26-Gear A, 27-Gear B, 28-Gear C, 29-Gear D, 30-Gear bracket, 31-Electromagnetic clutch A, 32-Electromagnetic clutch B, 33-Motor bracket, 34-Geared motor, 35-Motor, 36-Generator, 37-Battery, 38-Bellwall. Detailed Implementation

[0052] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. However, this is not the only description; all aspects not described in detail herein are based on conventional techniques in the art.

[0053] Example 1

[0054] A three-degree-of-freedom multifunctional transmission mechanism for underwater robots, such as Figures 1 to 8 As shown, it includes a wire drive unit, an energy conversion unit, and a structural support unit;

[0055] The structural support unit supports the entire mechanism; the cable drive unit enables the movement of three degrees of freedom: pitch, yaw, and roll; and the energy conversion unit meets the functional requirements of energy capture and drive control.

[0056] Example 2

[0057] A three-degree-of-freedom multifunctional transmission mechanism for underwater robots, as described in Embodiment 1, differs in that the cable transmission unit includes a yaw disc A 8, a yaw disc B 9, a transmission rope A 11, a transmission rope B 12, a yaw shaft 10, a hydraulic cylinder 13, a low-speed motor 2, a gear pump 5, an oil tank 1, an electromagnetic reversing valve 7, a valve block 6, a magnetic coupler A 4, a guide wheel A 14, a guide wheel B 15, a pitch shaft 16, a pitch shaft bracket 17, a winding shaft A 19, and a winding shaft B 20;

[0058] The structural support unit includes an end cap 18, a joint support 21, an upper cabin end cap 3, a lower cabin end cap 23, a gear bracket 30, a motor bracket 33, and a bellows 38.

[0059] There are two pitch axis brackets 17, which are fixedly connected to one side of the end cover 18. The two ends of the pitch axis 16 are movably connected to the pitch axis brackets 17. Guide wheels A 14 and B 15 are set at both ends of the pitch axis 16, and the pitch axis 16, guide wheels A 14 and B 15 can rotate together. The rear end clasp of the hydraulic cylinder 13 is sleeved with the middle of the pitch axis 16, and the front end clasp of the hydraulic cylinder 13 is sleeved with the middle of the yaw axis 10. The hydraulic cylinder 13 can rotate relative to the pitch axis 16 and the yaw axis 10 respectively. The pitch axis 16 and the yaw axis 10 are perpendicular to each other.

[0060] Yaw disc A 8 and yaw disc B 9 are respectively movably mounted at both ends of yaw axis 10. Yaw disc A 8 and yaw disc B 9 can rotate relative to yaw axis 10. Yaw disc A 8 is fixedly connected to the upper hull end cover 3, driving the next hull section to rotate, thereby achieving pitch or yaw motion.

[0061] The oil tank 1 and the low-speed motor 2 are fixedly installed inside the upper hull end cover 3. The low-speed motor 2 is coaxially connected to the input end of the magnetic coupler A 4. The gear pump 5 is fixedly installed outside the upper hull end cover 3 and coaxially connected to the output end of the magnetic coupler A 4. The valve block 6 is fixedly installed outside the upper hull end cover 3. The electromagnetic reversing valve 7 is fixedly connected to the valve block 6.

[0062] The energy conversion unit includes a reducer 22, a magnetic coupler B 24, a gear A 26, a gear B 27, a gear C 28, a gear D 29, an internal gear 25, an electromagnetic clutch A 31, an electromagnetic clutch B 32, an electric motor 35, a generator 36, a storage battery 37, and a geared motor 34.

[0063] The reducer 22 is fixedly mounted on the other side of the end cover 18. The reducer 22 has dual-shaft output, with the two output shafts arranged opposite each other. The input shaft of the reducer 22 is perpendicular to the two output shafts. The winding shaft A 19 and the winding shaft B 20 are respectively connected to the two output shafts of the reducer 22 and are parallel to the guide wheel A 14 and the guide wheel B 15 respectively. The input shaft of the reducer 22 is coaxially connected to the output end of the magnetic coupler B 24.

[0064] Gear A 26 is coaxially connected to the input end of magnetic coupler B 24. Gear B 27 meshes with gear A 26 and is coaxially connected to the output end of electromagnetic clutch A 31. The input end of electromagnetic clutch A 31 is connected to motor 35. Gear C 28 meshes with gear A 26 and is coaxially connected to the input end of electromagnetic clutch B 32. The output end of electromagnetic clutch B 32 is connected to generator 36. Gear B 27 and gear C 28 do not contact each other. Gear D 29 is coaxially connected to gear 34. Gear D 29 meshes with internal gear 25. Internal gear 25 is fixedly installed inside the lower hull end cover 23, driving the lower hull end cover 23 to rotate around the axis, realizing lateral rolling motion. Gear D 29 and internal gear 25 do not contact gear A 26, gear B 27, or gear C 28.

[0065] like Figure 2 The diagram shows the overall structure without the bellows. A joint support 21 is provided between the end cover 18 and the lower hull end cover 23. Gears A 26, B 27, C 28, and D 29 are installed on one side of the gear bracket 30. Electromagnetic clutches A 31, B 32, and the geared motor 34 are fixedly installed on the other side of the gear bracket 30. The gear bracket 30 is fixedly connected to the motor bracket 33. The generator 36, the motor 35, and the battery 37 are fixedly installed on the motor bracket 33. The motor bracket 33 is fixedly connected to the outer shell of the hull.

[0066] like Figure 3 The diagram shows the internal structure of a three-degree-of-freedom multifunctional transmission mechanism for an underwater robot, including a concealed bellows, joint support, motor bracket, gear bracket, upper cabin end cover, and lower cabin end cover. It clearly illustrates the transmission relationship within the energy conversion unit. When gear A 26 rotates, it drives the input shaft of magnetic coupler B 24 to rotate synchronously. By changing the magnetic field distribution inside magnetic coupler B 24, torque is transmitted to the output shaft of magnetic coupler B 24, which in turn drives the input shaft of reducer 22 to rotate, achieving non-contact power transmission. Similarly, non-contact power transmission is achieved between the low-speed motor 2 and the gear pump 5 via magnetic coupler 4A. Combined with the sealed end covers of the upper and lower cabins, the sealed separation between the cabin and the joint is ensured, effectively improving the reliability of the cabin's internal sealing.

[0067] like Figure 4 and Figure 5 The diagram shows a yaw disk A and a winding shaft of a three-degree-of-freedom multifunctional transmission mechanism for an underwater robot, combined with... Figure 7 and Figure 8The winding path of the transmission unit is clearly shown. Guide grooves are provided on the outer surfaces of yaw disc A8, yaw disc B9, guide wheel A14, and guide wheel B15. Guide wheel A14 and guide wheel B15 are provided with two guide grooves, one inner and one outer, while yaw disc A8 and yaw disc B9 are provided with one guide groove.

[0068] Spiral guide grooves are provided on the outer surfaces of winding shaft A 19 and winding shaft B 20. The spiral guide grooves of the two winding shafts rotate in opposite directions. The transmission rope A / transmission rope B moves in the guide grooves to prevent the transmission rope from slipping or tangling during the movement.

[0069] The transmission rope A11 is wound around the winding shaft A19, and a screw is used to fix the two turns of transmission rope in the middle to prevent the transmission rope from slipping and moving axially during operation, and to ensure winding stability. One outer end of the transmission rope A11 is wound and riveted to the yaw disc A8 after passing through the outer guide groove of the guide wheel A14, and the other inner end of the transmission rope A11 is wound onto the yaw disc B9 after passing through the inner guide groove of the guide wheel A14.

[0070] The transmission rope B12 is wound around the winding shaft B20, and a screw is used to fix the two turns of transmission rope in the middle. The outer end of the transmission rope B12 is wound and riveted to the yaw disc A8 after passing through the outer guide groove of the guide wheel B15. The inner end of the transmission rope B12 is wound around the yaw disc B9 after passing through the inner guide groove of the guide wheel B15, and is connected to the inner end of the transmission rope A11.

[0071] Both transmission rope A 11 and transmission rope B 12 are made of steel wire rope.

[0072] Example 3

[0073] A three-degree-of-freedom multifunctional transmission mechanism for an underwater robot, as described in Embodiment 2, differs in that the cylinder 13 can change the distance between the yaw axis 10 and the pitch axis 16, thereby adjusting the tension of the transmission rope and making the joint stiffness variable. When high stiffness is required (such as for precision operations or energy capture), the cylinder 13 extends to increase the tension of the transmission rope; when high compliance is required (such as for shock absorption or resistance to strong currents), the cylinder 13 shortens to reduce the tension of the transmission rope. The low-speed motor 2 drives the gear pump 5 through the magnetic coupler A 4, thereby controlling the hydraulic oil to enter the valve block 6 from the oil tank 1, and adjusting the extension and retraction of the piston rod of the cylinder 13 under the action of the electromagnetic reversing valve 7.

[0074] Example 4

[0075] A three-degree-of-freedom multifunctional transmission mechanism for underwater robots, as described in Embodiment 3, differs in that... Figure 1As shown, the upper and lower end caps are joints, and the rest of the structure is located inside the hull. The upper end cap 3 and the lower end cap 23 are sealed together by an aging-resistant rubber bellows 38. The connection is sealed with marine-grade vulcanized rubber, which achieves joint sealing while ensuring the flexibility of the joint during multi-degree-of-freedom movement.

[0076] Example 5

[0077] A method for operating a three-degree-of-freedom multifunctional transmission mechanism for an underwater robot, including a drive control mode and an energy harvesting mode;

[0078] like Figure 6 As shown, the downward arrow indicates the drive control phase, and the upward arrow indicates the energy capture phase;

[0079] In drive control mode, battery 37 provides energy to motor 35. Motor 35 transmits power to gear B 27 through electromagnetic clutch A31. At this time, electromagnetic clutch B 32 is in the disengaged state, generator 36 does not participate in the transmission process, gear B 27 meshes with gear A 26, so that power is transmitted to the input shaft of reducer 22 through magnetic coupler B 32, and then distributed to winding shaft A 19 and winding shaft B 20 through the two output shafts of reducer 22, thereby driving transmission rope A 11 and transmission rope B 12 to move.

[0080] When the winding shafts A 19 and B 20 rotate in the same direction under the drive of the output shaft of the reducer 22, the outer ends of the transmission ropes A 11 and B 12 extend / retract, and the inner ends retract / extend, thereby driving the yaw discs A 8 and B 9 to rotate together with the yaw shaft 10 and the hydraulic cylinder 13 around the pitch axis 16, realizing the pitch movement of the joint. Figure 7 As shown; when the winding shaft A 19 and the winding shaft B 20 rotate in opposite directions, the outer end of the transmission rope A 11 extends / retracts, and the inner end retracts / extends; the outer end of the transmission rope B 12 retracts / extends, and the inner end extends / retracts, thus driving the yaw disc A 8 to rotate around the yaw axis 10, thereby realizing the yaw motion of the joint, as shown. Figure 8 As shown;

[0081] In addition, the battery 37 can also power the geared motor 34, which transmits power to the gear D 29. The gear D 29 meshes with the internal gear 25, thereby driving the end cover of the cabin to rotate and realize the rolling motion of the joint.

[0082] In energy capture mode, the hull oscillates with the waves, and the change in the volume of displaced water causes buoyancy fluctuations. When the hull is lifted to the wave crest, the volume of displaced water decreases, resulting in buoyancy less than gravity and a downward resultant force. Conversely, when the hull sinks to the wave trough, the volume of displaced water increases, and buoyancy greater than gravity, creating an upward resultant force. This buoyancy difference drives the hull's oscillation. Due to the phase difference in the oscillation motion of the hulls on both sides of the joint, the hulls on both sides of the joint oscillate vertically under the joint's constraints, thus triggering the joint's pitch motion. The horizontal forward and backward motion of water particles generates significant thrust and pull on the hull, and the propagating waves create a phase difference in the underwater robot's longitudinal motion. This phase difference generates a recurring torque at the joint, converting the horizontal input of wave energy into a coordinated serpentine oscillation of the underwater robot in the horizontal plane, thus triggering the joint's yaw motion. The joint's pitch and yaw motions drive the yaw disk A8 to rotate, which is connected to the transmission rope B via transmission rope A11. The linkage of winding shafts A 19 and B 20 causes them to rotate. The rotational power of winding shafts A 19 and B 20 is transmitted to magnetic coupler B 24 via reducer 22, which drives gear A 26 to rotate. Gear A 26 meshes with gear C 28, allowing power to be transmitted to generator 36 via electromagnetic clutch B 32. At this time, electromagnetic clutch A 31 is in the disengaged state, motor 35 does not participate in the operation, and generator 36 converts mechanical energy into electrical energy and stores it in battery 37, thereby realizing energy recovery.

[0083] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A three-degree-of-freedom multifunctional transmission mechanism for underwater robots, characterized in that, It includes a wire drive unit, an energy conversion unit, and a structural support unit; The structural support unit is used to support the entire mechanism; the cable drive unit is used to realize the three degrees of freedom of movement: pitch, yaw and roll; the energy conversion unit is used to meet the two functional requirements of energy capture and drive control.

2. The three-degree-of-freedom multifunctional transmission mechanism for underwater robots according to claim 2, characterized in that, The cable drive unit includes yaw disc A, yaw disc B, drive rope A, drive rope B, yaw shaft, hydraulic cylinder, low-speed motor, gear pump, oil tank, electromagnetic reversing valve, valve block, magnetic coupler A, guide wheel A, guide wheel B, pitch shaft, pitch shaft bracket, winding shaft A, and winding shaft B. The structural support unit includes an end cap, a joint support, an upper cabin end cap, a lower cabin end cap, a gear bracket, a motor bracket, and a bellows. There are two pitch axis supports, each fixedly connected to one side of the end cap. The two ends of the pitch axis are movably connected to the pitch axis supports. Guide wheels A and B are located at both ends of the pitch axis, allowing the pitch axis to rotate together with guide wheels A and B. The rear end clasp of the hydraulic cylinder is sleeved with the middle of the pitch axis, and the front end clasp is sleeved with the middle of the yaw axis. The hydraulic cylinder can rotate relative to the pitch axis and yaw axis respectively. The pitch axis and yaw axis are perpendicular to each other in opposite planes. The yaw disk A and yaw disk B are respectively movably mounted at both ends of the yaw axis, and yaw disk A and yaw disk B can rotate relative to the yaw axis; the yaw disk A is fixedly connected to the end cover of the upper hull, driving the next section of the hull to rotate, thereby realizing pitch or yaw motion.

3. The three-degree-of-freedom multifunctional transmission mechanism for underwater robots according to claim 2, characterized in that, The oil tank and low-speed motor are fixedly installed inside the upper hull end cover. The low-speed motor is coaxially connected to the input end of the magnetic coupler A. The gear pump is fixedly installed outside the upper hull end cover and coaxially connected to the output end of the magnetic coupler A. The valve block is fixedly installed outside the upper hull end cover, and the electromagnetic reversing valve is fixedly connected to the valve block.

4. The three-degree-of-freedom multifunctional transmission mechanism for underwater robots according to claim 3, characterized in that, The energy conversion unit includes a reducer, a magnetic coupler B, gear A, gear B, gear C, gear D, an internal gear, an electromagnetic clutch A, an electromagnetic clutch B, an electric motor, a generator, a storage battery, and a geared motor. The reducer is fixedly installed on the other side of the end cover. The reducer has a dual-shaft output with the two output shafts arranged opposite each other. The input shaft of the reducer is perpendicular to the two output shafts. The winding shaft A and the winding shaft B are respectively connected to the two output shafts of the reducer and are parallel to the guide wheel A and the guide wheel B respectively. The input shaft of the reducer is coaxially connected to the output end of the magnetic coupler B. Gear A is coaxially connected to the input end of magnetic coupler B. Gear B meshes with gear A and is coaxially connected to the output end of electromagnetic clutch A. The input end of electromagnetic clutch A is connected to a motor. Gear C meshes with gear A and is coaxially connected to the input end of electromagnetic clutch B. The output end of electromagnetic clutch B is connected to a generator. Gear B and gear C do not contact each other. Gear D is coaxially connected to a reduction motor. Gear D meshes with an internal gear. The internal gear is fixedly installed inside the lower hull end cover, driving the lower hull end cover to rotate around the axis to achieve rolling motion. Gear D and the internal gear do not contact gear A, gear B, or gear C.

5. The three-degree-of-freedom multifunctional transmission mechanism for underwater robots according to claim 4, characterized in that, A joint support is provided between the end cover and the lower compartment end cover. Gears A, B, C, and D are installed on one side of the gear bracket. Electromagnetic clutches A and B and a reduction motor are fixedly installed on the other side of the gear bracket. The gear bracket is fixedly connected to the motor bracket. The generator, motor, and battery are fixedly installed on the motor bracket. The motor bracket is fixedly connected to the outer shell of the compartment. When gear A rotates, it drives the input shaft of magnetic coupler B to rotate synchronously. By changing the magnetic field distribution inside magnetic coupler B, the torque is transmitted to the output shaft of magnetic coupler B, which in turn drives the input shaft of the reducer to rotate, thus realizing non-contact power transmission. The low-speed motor and the gear pump also achieve non-contact power transmission through magnetic coupler A.

6. The three-degree-of-freedom multifunctional transmission mechanism for underwater robots according to claim 5, characterized in that, The outer surfaces of the yaw disk A, yaw disk B, guide wheel A, and guide wheel B are all provided with guide grooves. Guide wheel A and guide wheel B are provided with two guide grooves, one inner and one outer. Yaw disk A and yaw disk B are provided with one guide groove. Spiral guide grooves are provided on the outer surfaces of winding shaft A and winding shaft B. The spiral guide grooves of the two winding shafts rotate in opposite directions. The transmission rope A / transmission rope B moves in the guide grooves to prevent the transmission rope from slipping or tangling during the movement. The transmission rope A is wound around the winding shaft A, and a screw is set to fix the two turns of transmission rope in the middle to prevent the transmission rope from slipping and axial movement during operation, and to ensure winding stability. One outer end of the transmission rope A is wound and riveted to the yaw disc A after passing through the outer guide groove of the guide wheel A, and the other inner end of the transmission rope A is wound onto the yaw disc B after passing through the inner guide groove of the guide wheel A. The transmission rope B is wound around the winding shaft B, and a screw is used to fix the two turns of transmission rope in the middle. The outer end of the transmission rope B is wound and riveted to the yaw disc A after passing through the outer guide groove of the guide wheel B. The inner end of the transmission rope B is wound around the yaw disc B after passing through the inner guide groove of the guide wheel B, and is connected to the inner end of the transmission rope A.

7. The three-degree-of-freedom multifunctional transmission mechanism for underwater robots according to claim 6, characterized in that, Both transmission rope A and transmission rope B are made of steel wire rope.

8. The three-degree-of-freedom multifunctional transmission mechanism for underwater robots according to claim 7, characterized in that, The hydraulic cylinder can change the distance between the yaw axis and the pitch axis, thereby adjusting the tension of the transmission rope and making the joint stiffness variable. When high stiffness is required, the hydraulic cylinder extends to increase the tension of the transmission rope; when high compliance is required, the hydraulic cylinder shortens to reduce the tension of the transmission rope. The low-speed motor drives the gear pump through the magnetic coupler A, thereby controlling the hydraulic oil to enter the valve block from the oil tank, and adjusting the extension and retraction of the hydraulic cylinder piston rod under the action of the solenoid directional valve.

9. The three-degree-of-freedom multifunctional transmission mechanism for underwater robots according to claim 8, characterized in that, The upper hull end cap and the lower hull end cap are sealed together by an aging-resistant rubber bellows, and the connection is sealed with marine-grade vulcanized rubber.

10. A method for operating the three-degree-of-freedom multifunctional transmission mechanism for an underwater robot as described in any one of claims 1-9, characterized in that, Including drive control mode and energy capture mode; In drive control mode, the battery provides energy to the motor, and the motor transmits power to gear B through electromagnetic clutch A. At this time, electromagnetic clutch B is in the disengaged state, the generator does not participate in the transmission process, gear B meshes with gear A, so that the power is transmitted to the input shaft of the reducer through magnetic coupler B, and then distributed to the winding shaft A and winding shaft B respectively through the two output shafts of the reducer, thereby driving the transmission rope A and transmission rope B to move. When the winding shafts A and B rotate in the same direction under the drive of the reducer output shaft, the outer ends of the transmission ropes A and B extend / retract, and the inner ends retract / extend, thereby driving the yaw disc A, yaw disc B, yaw shaft, and hydraulic cylinder to rotate around the pitch axis, thus realizing the pitch movement of the joint; when the winding shafts A and B rotate in opposite directions, the outer ends of the transmission ropes A extend / retract, and the inner ends retract / extend, and the outer ends of the transmission ropes B retract / extend, and the inner ends extend / retract, thus driving the yaw disc A to rotate around the yaw axis, thereby realizing the yaw movement of the joint. In addition, the battery can also power the geared motor, which transmits power to gear D. Gear D meshes with the internal gear, thereby driving the end cover of the cabin to rotate and realize the rolling motion of the joint. In energy capture mode, the hull oscillates with the waves, and the change in the volume of displaced water causes buoyancy fluctuations. When the hull is lifted to the wave crest, the volume of displaced water decreases, resulting in buoyancy less than gravity, creating a downward resultant force. Conversely, when the hull sinks to the wave trough, the volume of displaced water increases, and buoyancy greater than gravity, creating an upward resultant force. This buoyancy difference drives the hull's oscillation motion. Due to the phase difference in the oscillation motion of the hulls on both sides of the joint, the hulls on both sides of the joint oscillate vertically under the joint's constraints, thus causing the joint's pitch motion. The horizontal forward and backward motion of water particles generates thrust and pull on the hull, and the propagating waves create a phase difference in the underwater robot's longitudinal motion. The phase difference generates a recurring torque at the joint, converting the horizontal input of wave energy into a coordinated serpentine oscillation of the underwater robot in the horizontal plane, which in turn triggers the yaw motion of the joint. The pitch and yaw motion of the joint drives the yaw disk A to rotate. Through the linkage of transmission rope A and transmission rope B, the winding shaft A and winding shaft B rotate accordingly. The rotational power of winding shaft A and winding shaft B is transmitted to the magnetic coupler B through the reducer, which drives gear A to rotate. Gear A meshes with gear C, so that the power is transmitted to the generator through the electromagnetic clutch B. At this time, the electromagnetic clutch A is in the open state, the motor does not participate in the operation, and the generator converts mechanical energy into electrical energy and stores it in the battery, thereby realizing energy recovery.

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