Rope-driven joint for multi-joint ocean robot and control method and application of rope-driven joint

Abstract

The invention relates to a rope-driven joint for a multi-joint ocean robot and a control method and application of the rope-driven joint, and belongs to the technical field of deep-sea submersibles, the rope-driven joint comprises a stay wire transmission unit, an energy conversion unit and a cabin support, the stay wire transmission unit comprises a winding shaft support, a large winding shaft, a small winding shaft and a steel wire rope, the energy conversion unit comprises a speed reducer, a magnetic coupler, a gear A, a gear B, a gear C, an electromagnetic clutch A, an electromagnetic clutch B, a motor and a generator; the shock resistance of the joint is improved through the built-in spring of the winding shaft, the axial force generated by stay wire transmission is avoided by improving the winding shaft structure and the winding mode, sealing is conducted in a magnetic coupling transmission mode, and the two functional requirements of energy capture and active driving can be met at the same time.

Description

Technical Field

[0001] The present invention relates to a cable-driven joint for a multi-joint underwater robot, its control method and application, belonging to the technical field of deep-sea submersibles. Background Art

[0002] As one of the most vast areas on the earth, the ocean contains rich resources and has huge development potential. The exploration of the ocean has become a strategic focus of countries around the world. As an important equipment for ocean research and development, underwater robots can carry a variety of electronic and mechanical devices, such as CTD profilers, Doppler loggers, manipulators, etc., and can achieve a wide range of ocean exploration and scientific education tasks, which is of great significance for in-depth understanding of the ocean environment, discovery of ocean resources, and promotion of the development of ocean science.

[0003] A multi-joint underwater robot is a special robot in the field of deep-sea exploration. It realizes steering and attitude control through the coordinated movement of multiple joints, rather than relying on a tail rudder or a complex buoyancy adjustment system. This design makes the underwater robot have a certain flexibility, which can improve its maneuverability and reduce the turning radius, so as to realize maneuvering operations in a smaller range.

[0004] Among them, the joints of a multi-joint underwater robot are the key structures for realizing high-efficiency maneuverability and flexible attitude control. Through the multi-degree-of-freedom movement of the joints, the underwater robot can achieve complex motion modes, such as pitching, yawing, and rolling, etc., so as to flexibly perform operations such as surfacing, diving, turning, and constant-depth cruising in the deep-sea environment. In terms of technical implementation, the joints of a multi-joint underwater robot usually include a driving unit and a transmission unit. The driving unit includes components such as motors, couplings, and drive shafts, while the transmission unit involves components such as gear racks and transmission shafts. This joint design enables the underwater robot to control its attitude by the rotation direction of the motor and the meshing of the gears when performing pitching and yawing movements. In addition, the joint design also needs to consider sealing to ensure the reliability of the underwater robot in the deep-sea high-pressure environment.

[0005] The existing patent document "A two-degree-of-freedom joint for a deep-sea multi-joint submersible" (application number 2019106280386) discloses a multi-joint submersible joint, which integrates two degrees of freedom on a single joint of the submersible, realizing two degrees of freedom of pitching and yawing, and improving the flexibility of the multi-joint submersible. However, its structure still adopts a rigid structure and is difficult to resist the impact force received during the working process.

[0006] The joints of existing multi-joint underwater robots have the following deficiencies: 1. Most joints adopt a rigid structure and are prone to damage under the impact of ocean currents in the actual working environment.

[0007] 2. The watertightness needs to be considered between the sealed cabin and the joints. Facing the deep-sea high-pressure environment, the reliability of the underwater robot is poor.

[0008] 3. The multi-joint structure form causes large energy loss during the movement of the underwater robot, making it difficult to ensure the endurance of the underwater robot. Summary of the Invention

[0009] Aiming at the deficiencies of the prior art, the present invention provides a cable-driven joint for a multi-joint underwater robot and its control method. The structure design is scientific and reasonable. The impact resistance of the joint is improved by installing a spring inside the winding shaft. The axial force generated by the cable drive is avoided by improving the winding shaft structure and winding method. Sealing is carried out by means of magnetic coupling drive, which can meet the two functional requirements of energy capture and active drive at the same time.

[0010] The technical solution of the present invention is as follows: A cable-driven joint for a multi-joint underwater robot, including a cable drive unit, an energy conversion unit and a cabin support. The cable drive unit includes a winding shaft bracket, a large winding shaft, a small winding shaft and a steel wire rope. The energy conversion unit includes a reducer, a magnetic coupler, Gear A, Gear B, Gear C, electromagnetic clutch A, electromagnetic clutch B, a motor and a generator; The winding shaft bracket is connected to the cabin support. The large winding shaft is arranged on the winding shaft bracket. A connecting plate is also connected to the large winding shaft. The connecting plate is connected to the next section of the cabin, or the connecting plate is the side plate of the next section of the cabin. The large winding shaft can rotate on the winding shaft bracket and drive the next section of the cabin to rotate through the connecting plate at the same time. The small winding shaft is installed on the output shaft of the reducer. The large winding shaft is connected to the small winding shaft through a steel wire rope to form a drive; The reducer is installed on the cabin support. Its input shaft and output shaft are perpendicular to each other. The input shaft is connected to the magnetic coupler. The magnetic coupler is connected to Gear C. The output shaft is connected to the small winding shaft; Gear C meshes with Gear A and Gear B respectively. Gear A and Gear B do not contact. The output end of electromagnetic clutch A is connected to Gear A. The output end of electromagnetic clutch B is connected to Gear B. The input end of electromagnetic clutch A is connected to the generator. The input end of electromagnetic clutch B is connected to the motor.

[0011] The motor, electromagnetic clutch B, Gear B, Gear C, magnetic coupler, reducer and cable drive unit are connected to form an active drive link; the cable drive unit, reducer, magnetic coupler, Gear C, Gear A, electromagnetic clutch A and generator are connected to form an energy collection link.

[0012] Preferably, with the cabin support as the demarcation line, the magnetic coupler, Gear A, Gear B, Gear C, electromagnetic clutch A, electromagnetic clutch B, the motor, and the generator are located inside the sealed cabin, while the speed reducer, the small winding shaft, the large winding shaft, the steel wire rope, and the winding shaft bracket are located outside the cabin body and immersed in seawater.

[0013] Preferably, a spring is arranged inside the small winding shaft, with the axis of the spring coinciding with the axis of the small winding shaft. One end of the spring is connected to the outer small winding shaft, and the other end of the spring is connected to the inner small winding shaft; the inner wall of the small winding shaft is pin-connected to the output shaft of the speed reducer. When the joint is impacted by an external force, the spring deforms to absorb the external force impact and prevent damage to the motor or the steel wire rope.

[0014] Preferably, spiral guiding grooves are provided on the outer surfaces of the large winding shaft and the small winding shaft, and the steel wire rope moves within the spiral guiding grooves. The spiral guiding grooves of the two winding shafts have the same helix direction. The guiding groove of the small winding shaft is a continuous section in the middle, and the guiding groove of the large winding shaft is divided into two sections on the left and right. The ratio of the pitches of the spiral guiding grooves of the two winding shafts is equal to the ratio of the diameters of the two winding shafts. This design can ensure that the transmission part of the steel wire rope is always perpendicular to the axes of the two winding shafts during the rotation of the joint, avoiding the axial force generated by the cable drive.

[0015] Preferably, the two ends of the steel wire rope are riveted to the starting points of the spiral guiding grooves on the surface of the large winding shaft through screws. Each end of the two ropes of the steel wire rope winds around the screw for half a turn, and the transmission between the large winding shaft and the small winding shaft is completed by one steel wire rope; a screw is arranged in the middle of the spiral guiding groove of the small winding shaft and straddles two turns of the steel wire rope to fix the steel wire rope on the small winding shaft. When the steel wire rope is installed and fixed, the winding parts of the steel wire rope are all wound in a right-handed direction, and the two rope ends are separately fixed on both sides.

[0016] Preferably, electromagnetic clutch A, electromagnetic clutch B, the motor, and the generator are installed on the motor mounting bracket, and the motor mounting bracket is connected to the cabin support and is all located inside the cabin.

[0017] More preferably, a storage battery is further provided on the motor mounting frame, and both the motor and the generator are connected to the storage battery.

[0018] A control method for a cable-driven joint of a multi-joint marine robot includes the following steps: When the marine robot is in the autonomous motion state, electromagnetic clutch A is powered off, electromagnetic clutch B is powered on, the cable-driven joint is connected to the motor, the storage battery provides energy for the motor, the motor drives Gear B to rotate through electromagnetic clutch B, Gear B drives Gear C to rotate, and thus drives the small winding shaft to rotate through the magnetic coupler and the speed reducer. Through the steel wire rope, the large winding shaft is driven to rotate at a certain angle of the joint to control the autonomous motion of the marine robot; When the multi-joint ocean robot is in the energy harvesting state, electromagnetic clutch A is energized, and electromagnetic clutch B is de-energized. The cable-driven joint is connected to the generator. The waves drive the relative movement of the sealed cabin bodies on both sides of the cable-driven joint, causing the large winding shaft to rotate. The small winding shaft is driven to rotate through the steel wire rope, and the gear A is driven to rotate through the reducer, magnetic coupling, and gear C. It is connected to the generator through the electromagnetic clutch to drive the generator to generate electricity for wave energy harvesting and charge the battery.

[0019] An ocean robot includes multiple sealed cabins, and two cabin bodies are connected by the aforementioned cable-driven joint.

[0020] The beneficial effects of the present invention are as follows: 1. The cable-driven joint of the multi-joint ocean robot of the present invention adopts cable drive, which occupies a small space. When the two winding shafts are displaced to a certain extent under the action of an external force, the cable can compensate for it, making the joint have a certain flexibility.

[0021] 2. Springs are built into the winding shafts. When the joint is subjected to an external impact, the springs can absorb part of the impact force, improving the anti-impact performance of the joint.

[0022] 3. The introduction of the guide groove and a cable winding method avoids the axial force in the cable drive.

[0023] 4. The transmission shafts inside and outside the sealed cabin are connected by magnetic coupling drive, ensuring the watertightness of the sealed cabin.

[0024] 5. Two functions, active drive and passive energy harvesting, are realized on one joint at the same time, making the overall structure of the multi-joint ocean robot more compact and improving its endurance. Description of the Drawings

[0025] Figure 1 It is the overall structure diagram of the multi-joint ocean robot; Figure 2 It is the overall structure diagram of a cable-driven joint for a multi-joint ocean robot; Figure 3 It is a cross-sectional view of a cable-driven joint for a multi-joint ocean robot. The scattered points in the figure are the flooded areas; Figure 4 It is a cross-sectional view of the small winding shaft of a cable-driven joint for a multi-joint ocean robot; Figure 5 It is a schematic diagram of the steel wire rope fixation of the large winding shaft of a cable-driven joint for a multi-joint ocean robot; Figure 6 It is a schematic diagram of the steel wire rope fixation of the small winding shaft of a cable-driven joint for a multi-joint ocean robot; Figure 7Schematic diagram of the assembly state of the wire rope of the cable-driven joint for a multi-joint underwater robot; Among them, 1 is the cabin support, 2 is the wire winding shaft bracket, 3 is the large wire winding shaft, 4 is the small wire winding shaft, 5 is the wire rope, 6 is the spring, 7 is the reducer, 8 is the magnetic coupler, 9 is gear A, 10 is gear B, 11 is gear C, 12 is electromagnetic clutch A, 13 is electromagnetic clutch B, 14 is the motor, 15 is the generator, 16 is the motor mounting bracket, and 17 is the storage battery. Specific implementation mode

[0026] The present invention will be further described below through embodiments in conjunction with the drawings, but is not limited thereto.

[0027] Embodiment 1: A cable-driven joint for a multi-joint underwater robot, as Figure 2 , Figure 3 shown, includes a wire-pulling transmission unit, an energy conversion unit, and a cabin support 1. The wire-pulling transmission unit includes a wire winding shaft bracket 2, a large wire winding shaft 3, a small wire winding shaft 4, and a wire rope 5. The energy conversion unit includes a reducer 7, a magnetic coupler 8, gear A 9, gear B 10, gear C 11, electromagnetic clutch A 12, electromagnetic clutch B 13, a motor 14, a generator 15, and a storage battery 17.

[0028] The wire winding shaft bracket is connected to and fixed on the cabin support. The large wire winding shaft is arranged on the wire winding shaft bracket. A connecting plate is also connected to the large wire winding shaft. The connecting plate is connected to the next section of the cabin, or the connecting plate is the side plate of the next section of the cabin. The large wire winding shaft can rotate on the wire winding shaft bracket and drive the next section of the cabin to rotate through the connecting plate at the same time. The small wire winding shaft is installed on the output shaft of the reducer. The large wire winding shaft is connected to the small wire winding shaft through a wire rope to form a transmission.

[0029] The reducer is installed on the cabin support. Its input shaft and output shaft are perpendicular to each other. The input shaft is connected to the magnetic coupler. The magnetic coupler is connected to gear C. The output shaft is connected to the small wire winding shaft.

[0030] Gear C meshes with gear A and gear B respectively. Gear A and gear B do not contact. The output end of electromagnetic clutch A is connected to gear A. The output end of electromagnetic clutch B is connected to gear B. The input end of electromagnetic clutch A is connected to the generator. The input end of electromagnetic clutch B is connected to the motor. Both the motor and the generator are connected to the storage battery.

[0031] The motor, electromagnetic clutch B, gear B, gear C, magnetic coupler, reducer, and wire-pulling transmission unit are connected to form an active drive link; the wire-pulling transmission unit, reducer, magnetic coupler, gear C, gear A, electromagnetic clutch A, and generator are connected to form an energy harvesting link.

[0032] Taking the cabin support as the demarcation line, the magnetic coupler, Gear A, Gear B, Gear C, electromagnetic clutch A, electromagnetic clutch B, motor, and generator are located inside the sealed cabin, while the reducer, small winding shaft, large winding shaft, steel wire rope, and winding shaft bracket are located outside the cabin and immersed in seawater, as Figure 3 shown.

[0033] Embodiment 2: A rope-driven joint for a multi-joint marine robot has the same structure as that in Embodiment 1, except that a spring 6 is arranged inside the small winding shaft, as Figure 4 shown. The axis of the spring coincides with the axis of the small winding shaft. One end of the spring is connected to the outer small winding shaft, and the other end of the spring is connected to the inner small winding shaft; the inner wall of the small winding shaft is pin-connected to the output shaft of the reducer. When the joint is impacted by an external force, the joint connected to the large winding shaft generates a torque due to the impact force, and the torsional impact is transmitted to the small winding shaft through the steel wire rope, as Figure 4 indicated by the arrow in. The spring deforms to absorb the external force impact and prevent damage to the motor or the steel wire rope.

[0034] Embodiment 3: A rope-driven joint for a multi-joint marine robot has the same structure as that in Embodiment 1, except that spiral guiding grooves are arranged on the outer surfaces of the large winding shaft and the small winding shaft, as Figure 5 , Figure 6 , Figure 7 shown. The steel wire rope moves in the spiral guiding grooves. The spiral guiding grooves of the two winding shafts have the same helix direction. The guiding groove of the small winding shaft is a continuous section in the middle, and the guiding groove of the large winding shaft is divided into left and right sections. As Figure 7 shown by the steel wire rope, the corresponding spiral guiding grooves at the corresponding positions can be known. The pitch ratio of the spiral guiding grooves of the two winding shafts is equal to the diameter ratio of the two winding shafts. This design can ensure that the steel wire rope transmission part is always perpendicular to the axes of the two winding shafts during the rotation of the joint, avoiding the axial force generated by the wire-pulling transmission. And the number of turns of the spiral guiding groove on the small winding shaft is greater than the number of turns of the actually wound steel wire rope, ensuring that the steel wire rope is still in the rope groove at the limit position after rotation.

[0035] The steel wire rope is riveted to the surface of the winding shaft by screws. Among them, the two ends of the steel wire rope are riveted to the starting points of the spiral guiding grooves on the surface of the large winding shaft by screws. Each of the two ends of the steel wire rope winds around the screw for half a turn, and the transmission between the large winding shaft and the small winding shaft is completed by one steel wire rope; a screw is arranged in the middle of the spiral guiding groove of the small winding shaft and straddles two turns of the steel wire rope to fix the steel wire rope on the small winding shaft. As Figure 7 shown, when the steel wire rope is installed and fixed, the winding parts of the steel wire rope are all wound in the right-handed direction, and the two ends are separately fixed on both sides.

[0036] Embodiment 4: A cable-driven joint for a multi-joint underwater robot, the structure of which is as described in Embodiment 1, except that electromagnetic clutch A, electromagnetic clutch B, a motor, a generator, and a storage battery are installed on a motor mounting bracket 16, and the motor mounting bracket is connected to the cabin support and is all located inside the cabin.

[0037] Embodiment 5: A control method for a cable-driven joint for a multi-joint underwater robot as described in Embodiment 1, including the following steps: When the underwater robot is in the autonomous motion state, electromagnetic clutch A is de-energized, electromagnetic clutch B is energized, the cable-driven joint is connected to the motor, and the storage battery provides energy for the motor. The motor drives gear B to rotate through electromagnetic clutch B, and gear B drives gear C to rotate. Thus, the small winding shaft is driven to rotate through the magnetic coupling and the speed reducer, and the large winding shaft is driven to rotate at a certain angle through the steel wire rope, controlling the autonomous motion of the underwater robot.

[0038] When the multi-joint underwater robot is in the energy harvesting state, electromagnetic clutch A is energized, electromagnetic clutch B is de-energized, the cable-driven joint is connected to the generator, and the relative motion of the sealed cabin bodies on both sides of the cable-driven joint is generated by the ocean waves, causing the large winding shaft to rotate. The small winding shaft is driven to rotate through the steel wire rope, and gear A is driven to rotate through the speed reducer, the magnetic coupling, and gear C, and is connected to the generator through the electromagnetic clutch to drive the generator to generate electricity for wave energy harvesting and charge the storage battery.

[0039] Embodiment 6: An underwater robot includes multiple sealed cabins, and two cabins are connected by the cable-driven joint as described in Embodiment 1. As Figure 1 shown.

Claims

1. A cable-driven joint for a multi-joint underwater robot, characterized in that It includes a wire-pulling drive unit, an energy conversion unit, and a cabin support. The wire-pulling drive unit includes a wire-winding shaft bracket, a large wire-winding shaft, a small wire-winding shaft, and a steel wire rope. The energy conversion unit includes a reducer, a magnetic coupler, Gear A, Gear B, Gear C, electromagnetic clutch A, electromagnetic clutch B, a motor, and a generator. The wire-winding shaft bracket is connected to the cabin support. The large wire-winding shaft is arranged on the wire-winding shaft bracket. A connecting plate is also connected to the large wire-winding shaft. The connecting plate is connected to the next cabin section, or the connecting plate is a side plate of the next cabin section. The small wire-winding shaft is installed on the output shaft of the reducer. The large wire-winding shaft is connected to the small wire-winding shaft through a steel wire rope to form a drive. The reducer is installed on the cabin support. Its input shaft and output shaft are perpendicular to each other. The input shaft is connected to the magnetic coupler. The magnetic coupler is connected to Gear C. The output shaft is connected to the small wire-winding shaft. Gear C meshes with Gear A and Gear B respectively. The output end of electromagnetic clutch A is connected to Gear A. The output end of electromagnetic clutch B is connected to Gear B. The input end of electromagnetic clutch A is connected to the generator. The input end of electromagnetic clutch B is connected to the motor.

2. The cable-driven joint for a multi-joint underwater robot according to claim 1, wherein, Taking the cabin support as the dividing line, the magnetic coupler, Gear A, Gear B, Gear C, electromagnetic clutch A, electromagnetic clutch B, the motor, and the generator are located inside the sealed cabin. The reducer, the small wire-winding shaft, the large wire-winding shaft, the steel wire rope, and the wire-winding shaft bracket are located outside the cabin.

3. The cable-driven joint for a multi-joint marine robot according to claim 1, wherein A spring is arranged inside the small wire-winding shaft. The axis of the spring coincides with the axis of the small wire-winding shaft. The inner wall of the small wire-winding shaft is pin-connected to the output shaft of the reducer.

4. The cable-driven joint for a multi-joint underwater robot according to claim 1, wherein Spiral guide grooves are provided on the outer surfaces of the large wire-winding shaft and the small wire-winding shaft. The steel wire rope moves in the spiral guide grooves. The spiral guide grooves of the two wire-winding shafts have the same helix direction. The guide groove of the small wire-winding shaft is a continuous section in the middle. The pitch ratio of the spiral guide grooves of the two wire-winding shafts is equal to the diameter ratio of the two wire-winding shafts.

5. The cable-driven joint for a multi-joint marine robot according to claim 1, wherein The two ends of the steel wire rope are riveted to the starting point of the spiral guide groove on the surface of the large wire-winding shaft through screws. A screw is arranged in the middle of the spiral guide groove of the small wire-winding shaft and straddles two turns of the steel wire rope.

6. The cable-driven joint for a multi-joint marine robot according to claim 1, characterized in that, Electromagnetic clutch A, electromagnetic clutch B, the motor, and the generator are installed on the motor mounting bracket. The motor mounting bracket is connected to the cabin support and is all located inside the cabin.

7. The cable-driven joint for a multi-joint underwater robot according to claim 6, wherein A storage battery is also provided on the motor mounting frame. The motor and the generator are both connected to the storage battery.

8. A control method for a cable-driven joint of a multi-joint underwater robot according to any one of claims 1-7, characterized in that, It includes the following steps: When the marine robot is in the autonomous motion state, electromagnetic clutch A is powered off, and electromagnetic clutch B is powered on. The cable-driven joint is connected to the motor. The storage battery provides energy for the motor. The motor drives Gear B to rotate through electromagnetic clutch B. Gear B drives Gear C to rotate. Then, through the magnetic coupler and the reducer, the small wire-winding shaft is driven to rotate. Through the steel wire rope, the large wire-winding shaft is driven to make a joint rotation at a certain angle to control the autonomous motion of the marine robot. When the multi-joint underwater robot is in the energy harvesting state, electromagnetic clutch A is energized and electromagnetic clutch B is de-energized. The cable-driven joint is connected to the generator. The wave drives the relative movement of the sealed cabin bodies on both sides of the cable-driven joint, causing the large winding shaft to rotate. The small winding shaft is driven to rotate through the steel wire rope, and the gear A is driven to rotate through the reducer, magnetic coupler, and gear C. It is connected to the generator through the electromagnetic clutch to drive the generator to generate electricity for wave energy harvesting and charge the battery.

9. An ocean robot, characterized in that, It includes multiple sections of sealed cabins, and two cabin bodies are connected by the cable-driven joint described in any one of claims 1-7.

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