Underwater soft manipulator, underwater robot and grasping method thereof

Abstract

The application provides an underwater soft manipulator, an underwater robot and a grabbing method thereof, and comprises one arm and three fingers, the arm is connected with the three fingers, and the arm and the three fingers are characterized in that: the arm and the three fingers each comprise a flexible structure fabric, an elastic tubular air bag and a sealing film, the elastic tubular air bag serves as a framework, the flexible structure fabric is sleeved on the outer side of the elastic tubular air bag, and the sealing film covers the flexible structure fabric. The arm and the three fingers each form a sealed chamber formed by the sealing film and a connecting piece, and the elastic tubular air bag in the sealed chamber is independently controlled through negative pressure and positive pressure, so that underwater multi-degree-of-freedom movement, spatial positioning and grabbing actions are realized. The underwater manipulator can realize multi-degree-of-freedom movement and variable stiffness performance, so that the flexibility, adaptability and reliability of underwater operation of the manipulator are improved, and the underwater manipulator also has the advantage of light weight; the grabbing method is controlled through positive and negative air pressure to realize underwater multi-degree-of-freedom movement, spatial positioning and grabbing and other complex actions.

Description

Technical Field

[0001] This invention belongs to the field of robotics technology and relates to the improvement of underwater manipulators, specifically an underwater soft manipulator, an underwater robot and its grasping method. Background Technology

[0002] Underwater robots have wide applications in marine engineering, scientific research, and resource exploration. As a key component of underwater robots, the robotic arm is typically used to perform various complex tasks, such as sampling, maintenance, and material handling.

[0003] Currently, the common manipulator structures for underwater robots mainly include parallel manipulators and serial manipulators. Serial manipulators have a simple structure and are easy to control, but their flexibility and load-bearing capacity are relatively poor, limiting their ability to perform some complex tasks in underwater environments, and they are prone to generating large moments of inertia during movement. Parallel manipulators, while possessing high rigidity and precision, have a complex structure, including multiple joints and connectors, making them susceptible to the effects of water flow, thus reducing their operational stability and flexibility.

[0004] In view of this, designing a new type of underwater manipulator by applying new principles and methods to complete various complex underwater operations under the influence of water flow and other environmental factors, and to achieve stable and efficient operation of the robot, is a current challenge for underwater robots.

[0005] Given the limitations of parallel and serial manipulators in underwater robotics applications, a key challenge lies in designing an underwater soft manipulator, an underwater robot, and its grasping method that can achieve multi-freedom motion and variable stiffness, thereby improving the manipulator's flexibility and adaptability in underwater operations. Furthermore, compared to traditional rigid manipulators, this soft manipulator offers the advantage of being lightweight, thus minimizing its impact on the robot's moment of inertia. Additionally, its variable stiffness capability ensures safe underwater operation. This is a pressing technical problem that needs to be solved in this field. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention provides an underwater soft manipulator, an underwater robot, and its grasping method. This invention enables multi-degree-of-freedom motion and variable stiffness, thereby improving the manipulator's flexibility, adaptability, and reliability in underwater operations. Furthermore, it has the advantage of being lightweight. The grasping method utilizes positive and negative air pressure control to achieve complex underwater multi-degree-of-freedom motion, spatial positioning, and grasping.

[0007] The objective of this invention is achieved through the following technical solution: An underwater soft robotic hand includes an arm and three fingers, wherein the arm and the three fingers are connected. The arm and the three fingers each comprise a flexible structural fabric, an elastic tubular air bladder, and a sealing membrane. The elastic tubular air bladder serves as a skeleton, the flexible structural fabric is fitted over the outer surface of the elastic tubular air bladder, and the sealing membrane covers the flexible structural fabric within it. Each arm and each of the three fingers forms a sealed chamber consisting of a sealing membrane and a connector. The elastic tubular air bladder within each chamber is independently controlled by negative and positive pressure, enabling underwater multi-degree-of-freedom movement, spatial positioning, and grasping actions.

[0008] Improvements to the above technical solution: The flexible structural fabric is composed of several hollow spherical units with different characteristic lengths; each hollow spherical unit has the same geometric features and different spatial orientations. Horizontally placed hollow spherical units are called horizontal spherical units, and vertically placed hollow spherical units are called vertical spherical units. The vertical spherical units and the horizontal spherical units are periodically connected together to form a ring-shaped flexible structural fabric; the elastic tubular airbag includes an airbag, an inflation plug, and an inflation tube. The top of the airbag is bonded to the lower end of the inflation plug, and the inflation tube is bonded to the tube at the top of the inflation plug to form a complete inflation tube.

[0009] Further improvements to the above technical solution: The airbag in the arm includes three cylindrical airbags, the inflatable plug in the arm includes three cylindrical inflatable plugs, the airbag in each finger includes two semi-cylindrical airbags, and the inflatable plug in each finger includes two semi-cylindrical inflatable plugs; the connector includes an arm connecting plate and a finger connecting plate, with one side of the arm connecting plate and the finger connecting plate respectively connected to both ends of the arm, and the other side of the three fingers connected to the finger connecting plate; the arm connecting plate is evenly provided with three circular holes, each connected to one of the three cylindrical inflatable plugs; the finger connecting plate is provided with six semi-cylindrical holes, with two semi-cylindrical holes forming a pair, and the three pairs of semi-cylindrical holes are respectively connected to the six semi-cylindrical inflatable plugs; the arm connecting plate is provided with an air intake tube and an inflatable tube, and the finger connecting plate is provided with an air intake tube and an inflatable tube; the air intake tube on the arm connecting plate communicates with the cylindrical airbags, and the air intake tube on the finger connecting plate communicates with the semi-cylindrical airbags.

[0010] Further improvements to the above technical solution: The sealing film is made of polyethylene film, a sealing plate is provided at the fingertip, and the sealing film covering the finger, together with the arm connecting plate and the sealing plate, forms the sealing chamber; the sealing film covering the arm, together with the arm connecting plate and the finger connecting plate, forms the sealing chamber.

[0011] Further improvement to the above technical solution: the three fingers have the same structure and are evenly spaced on the finger connecting plate.

[0012] Further improvements to the above technical solution: The arm connecting plate, finger connecting plate and sealing plate are all made of PLA material by 3D printing.

[0013] Further improvement to the above technical solution: The flexible structure fabric is made of flexible TPU material by 3D printing.

[0014] An underwater robot includes a robot body, a manipulator, and a control system. The manipulator is an underwater soft manipulator as described above. An air pump and a vacuum pump are installed within the robot body. The air pump is connected via pipes to air inflator tubes in the arm and fingers of the underwater soft manipulator. The vacuum pump is connected via pipes to suction tubes in the arm and fingers of the underwater soft manipulator. The control terminals of the air pump and the vacuum pump are connected to the control system.

[0015] A grasping method for the above-mentioned underwater robot, characterized in that the grasping method includes the following steps: S1: The control system controls the underwater robot to move to the target working area. According to the work requirements, it controls the pressure of the airbag in the arm to move the arm to the target position. S2: After the arm moves to the target position, the control system applies negative pressure to the arm through a vacuum pump, so that the arm is in a high-rigidity state and maintains a stable spatial posture. S3: The control system inflates the air bladder inside the finger with an air pump, and uses positive pressure to drive the finger to grip the object. After gripping the target object, the control system applies negative pressure to the finger with a vacuum pump, so that the robotic hand finger is in a high-rigidity state, thereby achieving stable gripping of the target. S4: The control system controls the underwater robot to move to the target release area. According to the work requirements, it restores the sealed chamber of the arm to the normal pressure state and controls the pressure of the three airbags at the arm. The arm moves to the target release position. S5: Restore the sealed chamber of the finger to normal pressure and control the pressure of the air bladder inside the finger to place the target object in the designated position; S6: Repeat the above steps until the underwater operation is completed. Then, stop the positive and negative pressure of the air pump and vacuum pump in the entire underwater robot and control the underwater robot to retract.

[0016] The advantages and positive effects of this invention are: As can be seen from the above technical solution, the multi-degree-of-freedom, variable-stiffness underwater manipulator based on flexible fabric structure provided by the present invention has at least one or a part of the following beneficial effects: 1. The multi-degree-of-freedom, variable-stiffness underwater manipulator based on flexible structure fabric of the present invention has the characteristics of light weight in its flexible structure fabric, elastic tubular airbag and sealing membrane, etc. Compared with mechanical rigid manipulator, it can avoid the generation of large rotational inertia during the movement of the manipulator, thereby ensuring the stability of the underwater robot. 2. The underwater manipulator of the present invention, based on a flexible structure fabric, has a multi-degree-of-freedom and variable stiffness. Its arm can achieve multi-angle bending motion in space by controlling three airbags, and its manipulator can achieve bending in both forward and reverse directions by controlling two airbags. At the same time, the stiffness of its arm and fingers can be controlled by negative pressure. The variable stiffness soft gripper can wrap around and stably grasp the target object. 3. The underwater manipulator of the present invention, which is based on a flexible structure fabric and has multiple degrees of freedom and variable stiffness, has its arms and fingers designed and assembled separately, which can achieve overall modularity. When the length of the manipulator cannot meet the requirements of the work task, an additional set (or several sets) of arms can be added to achieve overall lengthening by stacking the same arms. The connection between the arms is basically the same as the connection between the arms and the fingers.

[0017] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0018] Figure 1 This is a three-dimensional view of the hollow spherical unit cell of the flexible structural fabric in the underwater soft manipulator of the present invention. Figure 2 This is a schematic diagram of the extension and retraction of the flexible structure fabric in the underwater soft manipulator of the present invention; Figure 3 This is a perspective view of the underwater soft robotic arm of the present invention. Figure 4 This is a top view of the arm of the underwater soft robotic arm of the present invention; Figure 5 This is a perspective view of the finger in the underwater soft robotic hand of the present invention; Figure 6 This is a top view of the finger in the underwater soft robotic hand of the present invention; Figure 7 This is a schematic diagram of the airbag at the arm of the underwater soft robotic arm of the present invention; Figure 8 This is a schematic diagram of the air bladder at the finger of the underwater soft robotic hand of the present invention; Figure 9 This is a schematic diagram of the arm connecting plate structure in the underwater soft manipulator of the present invention; Figure 10 A schematic diagram of the finger connecting plate structure in the underwater soft robotic hand of the present invention; Figure 11 This is a schematic diagram of the airbag arrangement in the underwater soft manipulator of the present invention.

[0019] Figure 12 This is a control principle diagram of the underwater soft manipulator of the present invention; Figure 13 This is a flowchart of the underwater robot grasping method of the present invention; Figure 14 This is a schematic diagram of the underwater robot of the present invention.

[0020] The components in the diagram are numbered as follows: 1. Inflation tube; 2. Suction tube; 3. Circular tubular inflation plug; 4. Arm connecting plate; 4.1. First air extraction port; 4.2. Circular hole; 5. Circular tubular airbag; 6. Semi-circular tubular inflation plug; 7. Finger connecting plate; 7.1. Second air extraction port; 7.2. Semi-circular hole; 8. Semi-circular tubular airbag; 9. Flexible structure fabric; 10. Sealing membrane; 11. Inflation pump; 12. Pressure regulating valve; 13. Vacuum pump; 14. Underwater soft manipulator; 15. Robot body. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the accompanying drawings: See Figures 1-10 This invention discloses an embodiment of an underwater soft manipulator, comprising an arm and three fingers. The arm and the three fingers are connected. Each arm and the three fingers includes a flexible structural fabric 9, an elastic tubular air bladder, and a sealing membrane 10. The elastic tubular air bladder serves as a skeleton. The flexible structural fabric 9 is fitted onto the outer surface of the elastic tubular air bladder, and the sealing membrane 10 covers the flexible structural fabric 9 within it. Each arm and each of the three fingers forms a sealed chamber formed by the sealing membrane 10 and a connector. The elastic tubular air bladder within each chamber is independently controlled by negative and positive pressure, respectively, to achieve underwater multi-degree-of-freedom movement, spatial positioning, and grasping actions.

[0022] Specifically: the aforementioned flexible structural fabric 9 is composed of several hollow spherical units with different characteristic lengths; each hollow spherical unit has the same geometric features but different spatial orientations. Horizontally placed hollow spherical units are called horizontal spherical units, and vertically placed hollow spherical units are called vertical spherical units. The vertical spherical units and the horizontal spherical units are periodically connected together to form a ring-shaped flexible structural fabric 9. The aforementioned elastic tubular airbag includes an airbag, an inflation plug, and an inflation tube 1. The top of the airbag is bonded to the lower end of the inflation plug, and the inflation tube is bonded to the tube at the top of the inflation plug, forming a complete inflation tube.

[0023] The flexible structural fabric 9 is composed of hollow spherical unit cells with the same geometric characteristics but different spatial orientations. The structure of the hollow spherical unit cells is as follows: Figure 1 As shown. Connecting the aforementioned hollow spherical unit cells together in a nested, interlocking manner forms the flexible structural fabric 9. The flexible structural fabric 9 can be made of flexible TPU material using 3D printing. When the flexible structural fabric 9 is stretched horizontally and vertically, the gaps between the hollow spherical unit cells shorten, and the flexible structural fabric 9 is elongated, as shown... Figure 2 As shown.

[0024] like Figure 3 , Figure 4 As shown, the flexible structural fabric 9 in the arm is composed of two types of hollow spherical unit cells of different sizes. The fabric structure with an effective length (the diameter of the sphere in the unit cell) of dA (structure A) forms the outer ring of the arm, while the fabric structure with an effective length (the diameter of the sphere in the unit cell) of dB (structure B) forms the inner skeleton of the arm. The inner skeleton divides the arm into three sector-shaped units with an included angle of 120°. dA is significantly larger than dB, and the gaps between the hollow spherical unit cells of the outer ring of the arm are larger than those in its inner skeleton. Figure 5 , Figure 6 As shown in the schematic diagram of the finger structure, the flexible structural fabric 9 of the finger is also composed of two hollow spherical unit cells of different sizes. Structure A forms the outer ring of the finger, and structure B forms the inner skeleton of the finger. The inner skeleton of the finger divides the finger into two semi-circular units. dA is significantly larger than dB, and the gap between the hollow spherical unit cells of the outer ring of the finger is larger than that between its inner skeleton and the outer ring.

[0025] Furthermore, the air bladder in the arm includes three cylindrical air bladders 5, the inflator in the arm includes three cylindrical inflator plugs 3, the air bladder in each finger includes two semi-cylindrical air bladders 8, and the inflator in each finger includes two semi-cylindrical inflator plugs 6.

[0026] like Figure 7 As shown, when a cylindrical airbag 5 at the arm is inflated and pressurized, the airbag 5 expands and deforms, causing the outer ring of the arm to elongate. Constrained by the arm's internal skeleton, the arm bends in the opposite direction to the cylindrical airbag 5. With the combined action of three inflated cylindrical airbags 5, the arm can bend to any angle in space. Similarly, as... Figure 8 As shown, when one of the semi-circular tubular air bladders 8 at the finger is inflated and pressurized, the finger will bend in the opposite direction to the semi-circular tubular air bladder 8. With the combined action of the two semi-circular tubular air bladders 8 at the finger, the finger can bend in both forward and reverse directions.

[0027] like Figure 9 , Figure 10As shown, the aforementioned connectors include an arm connecting plate 4 and a finger connecting plate 7. The two ends of the arm are connected to one side of the arm connecting plate 4 and the finger connecting plate 7, respectively, and the three fingers are connected to the other side of the finger connecting plate 7. The arm connecting plate 4 has three evenly spaced circular holes 4.2, each connected to one of three cylindrical air plugs 3. The finger connecting plate 7 has six semi-circular holes 7.2, with two semi-circular holes 7.2 forming a pair, and the three pairs of semi-circular holes 7.2 are each connected to one of the six semi-circular tubular air plugs 6. Both the arm connecting plate 4 and the finger connecting plate 7 are triangular in shape, with rounded corners. A first suction port 4.1 is provided on the arm connecting plate 4, and a second suction port 7.1 is provided on the finger connecting plate 7. Suction pipes 2 are installed on the first and second suction ports 4.1, and a vacuum pump 13 is used to create a vacuum, ensuring the arm and fingers are in a high-rigidity state.

[0028] Furthermore, the sealing film 10 is made of polyethylene film, and a sealing plate is provided at the fingertip. The sealing film 10 covering the finger, together with the arm connecting plate 4 and the sealing plate, forms the sealing chamber. The sealing film 10 covering the arm, together with the arm connecting plate 4 and the finger connecting plate 7, forms the sealing chamber.

[0029] When the sealed chamber is evacuated, the flexible fabric structure 9 inside is pressed together, increasing the compressive and frictional forces between the hollow spherical unit cells, thus increasing the rigidity of the manipulator and enabling it to maintain a stable posture. Applying negative pressure to the flexible fabric structure 9 transforms it into a rigid state, allowing it to maintain a stable shape to support objects of a certain weight. When the pressure inside the sealed chamber is restored to atmospheric pressure, the manipulator returns to its flexible state under the elastic restoring force of the hollow spherical unit cells.

[0030] Furthermore, the three fingers mentioned above have the same structure and are set at 120° intervals on the finger connecting plate 7.

[0031] Furthermore, the aforementioned arm connecting plate 4, finger connecting plate 7, and sealing plate are all made of PLA material using 3D printing.

[0032] Preferably, the flexible structural fabric 9 is made of flexible TPU material by 3D printing.

[0033] In specific implementation, the airbag arrangement of the present invention is as follows: Figure 11As shown, the inflation tube 1, together with the cylindrical inflation plug 3 and the cylindrical airbag 5, forms an inflation pipeline and is placed inside the arm connecting plate 4. The inflation tube 1, together with the semi-circular inflation plug 6 and the semi-circular airbag 8, forms an inflation pipeline and is placed inside the finger connecting plate 7. The suction tube 2 is directly connected to the sealed chamber formed by the sealing membrane 10 through pre-drilled holes in the arm connecting plate 4 and the finger connecting plate 7. The flexible fabric 9 and either the cylindrical airbag 5 or the semi-circular airbag 8 are wrapped by the sealing membrane 10. Figure 12 As shown, the air pump 11 generates positive pressure, and the pressure regulating valve 12 adjusts the bending direction and angle of the arm by different pressures of the three circular tubular airbags 5 at the arm. When the arm reaches the target position, the vacuum pump 13 is turned on and the pressure regulating valve is used to adjust the air pressure in the sealed chamber to make the arm reach a high rigidity state. The air pump 11 generates positive pressure and the pressure regulating valve adjusts the different pressures of the inner and outer semi-circular tubular airbags 8 of the fingers to realize the inner and outer bending of the mechanical fingers. When the robotic hand completes the gripping of the object, the vacuum pump 13 is turned on and the pressure regulating valve is used to make the mechanical fingers reach a high rigidity state to achieve stable gripping of the object.

[0034] See Figures 1-12 , Figure 14 This invention discloses an embodiment of an underwater robot, comprising a robot body 15, a manipulator, and a control system. The manipulator is the underwater soft manipulator 14 described in the above embodiment. An air pump 11 and a vacuum pump 13 are installed within the robot body 15. The air pump 11 is connected to the air inflator tubes 1 in the arm and fingers via pipes, and the vacuum pump 13 is connected to the suction tubes 2 in the arm and fingers via pipes. The control terminals of the air pump 11 and the vacuum pump 13 are connected to the control system. The underwater soft manipulator 14 is positioned at the front of the robot body 15. A visual sensor located below the underwater soft manipulator 14 can obtain the underwater robot's forward direction and bottom image. The underwater soft manipulator 14 can be controlled to complete various tasks of the underwater robot as required.

[0035] See Figures 1-14 An embodiment of the above-mentioned grasping method for underwater robots according to the present invention includes the following steps: S1: The control system controls the underwater robot to move to the target working area. According to the work requirements, it controls the pressure of the cylindrical airbag 5 in the arm to make the arm move to the target position. S2: After the arm moves to the target position, the control system applies negative pressure to the arm through the vacuum pump 13, so that the arm is in a high-rigidity state and maintains a stable spatial posture. S3: The control system inflates the semi-circular tubular airbag 8 inside the finger through the air pump 11, and drives the robotic hand finger to grasp the object through positive pressure. After grasping the target object, the control vacuum pump 13 applies negative pressure to the finger, so that the finger is in a high-rigidity state, thereby achieving stable grasping of the target. S4: The control system controls the underwater robot to move to the target release area. According to the work requirements, it restores the sealed cavity of the arm to the normal pressure state and controls the pressure of the three cylindrical airbags 5 at the arm. The arm moves to the target release position. S5: Restore the sealed chamber of the finger to normal pressure and control the pressure of the semi-circular tubular airbag 8 inside the robotic hand finger to place the target object in the designated position; S6: Repeat the above steps until the underwater operation is completed, then stop the positive and negative pressure of the air pump 11 and vacuum pump 13 in the entire underwater robot, and control the underwater robot to retract.

[0036] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. An underwater soft robotic hand, comprising one arm and three fingers, wherein the arm is connected to the three fingers, characterized in that, The arm and the three fingers each comprise a flexible structural fabric, an elastic tubular air bladder, and a sealing membrane. The elastic tubular air bladder serves as a framework, the flexible structural fabric is fitted over the outer surface of the elastic tubular air bladder, and the sealing membrane covers the flexible structural fabric within it. The arm and the three fingers each form a sealed chamber consisting of a sealing membrane and a connector. The elastic tubular air bladders within these chambers are independently controlled by negative and positive pressure, enabling underwater multi-degree-of-freedom movement, spatial positioning, and grasping actions. The flexible fabric structure is composed of several hollow spherical units with different characteristic lengths. Each hollow spherical unit has the same geometric features but different spatial orientations; horizontally placed hollow spherical units are called horizontal spherical units, and vertically placed hollow spherical units are called vertical spherical units. The vertical spherical unit cells are periodically connected to the horizontal spherical unit cells to form a ring-shaped flexible structure fabric; the elastic tubular air bladder includes an air bladder, an inflation plug, and an inflation tube, the top of the air bladder is bonded to the lower end of the inflation plug, and the inflation tube is bonded to the tube at the top of the inflation plug to form a complete inflation channel; the air bladder in the arm includes 3 circular tubular air bladders, the inflation plug in the arm includes 3 circular tubular inflation plugs, the air bladder in each finger includes 2 semi-circular tubular air bladders, and the air bladder in each finger... The inflatable plug includes two semi-circular tubular inflatable plugs; the connector includes an arm connecting plate and a finger connecting plate, with one side of the arm connecting plate and the finger connecting plate respectively connected to both ends of the arm, and the three fingers connected to the other side of the finger connecting plate. The arm connecting plate has three evenly spaced circular holes, each connected to one of the three tubular inflatable plugs. The finger connecting plate has six semi-circular holes, with two semi-circular holes forming a pair, and the three pairs of semi-circular holes each connected to one of the six tubular inflatable plugs. The arm connecting plate has a suction... The trachea and the inflation tube are provided; the finger connecting plate is provided with an inhalation tube and the inflation tube; the inhalation tube on the arm connecting plate is connected to the cylindrical air bladder; the inhalation tube on the finger connecting plate is connected to the semi-cylindrical air bladder; the sealing membrane is made of polyethylene film; a sealing plate is provided at the fingertip; the sealing membrane covering the finger, together with the arm connecting plate and the sealing plate, forms the sealed cavity; the sealing membrane covering the arm, together with the arm connecting plate and the finger connecting plate, forms the sealed cavity.

2. The underwater soft manipulator according to claim 1, characterized in that, The three fingers have the same structure and are evenly spaced on the finger connecting plate.

3. The underwater soft manipulator according to claim 1 or 2, characterized in that, The arm connecting plate, finger connecting plate, and sealing plate are all made of PLA material using 3D printing.

4. The underwater soft manipulator according to claim 1 or 2, characterized in that, The flexible structure fabric is made of flexible TPU material using 3D printing.

5. An underwater robot, comprising a robot body, a manipulator, and a control system, characterized in that, The robotic arm is an underwater soft robotic arm as described in any one of claims 1-4. An air pump and a vacuum pump are installed inside the robot body. The air pump is connected to the air inflator tubes in the arm and fingers of the underwater soft robotic arm through pipelines. The vacuum pump is connected to the suction tubes in the arm and fingers of the underwater soft robotic arm through pipelines. The control terminals of the air pump and the vacuum pump are respectively connected to the control system.

6. A grasping method for an underwater robot as described in claim 5, characterized in that, The crawling method includes the following steps: S1: The control system controls the underwater robot to move to the target working area. According to the work requirements, it controls the pressure of the airbag in the arm to move the arm to the target position. S2: After the arm moves to the target position, the control system applies negative pressure to the arm through a vacuum pump, so that the arm is in a high-rigidity state and maintains a stable spatial posture. S3: The control system inflates the air bladder inside the finger with an air pump, and uses positive pressure to drive the finger to grip the object. After gripping the target object, the control system applies negative pressure to the finger with a vacuum pump, so that the robotic hand finger is in a high-rigidity state, thereby achieving stable gripping of the target. S4: The control system controls the underwater robot to move to the target release area. According to the work requirements, it restores the sealed chamber of the arm to the normal pressure state and controls the pressure of the three airbags at the arm. The arm moves to the target release position. S5: Restore the sealed chamber of the finger to normal pressure and control the pressure of the air bladder inside the finger to place the target object in the designated position; S6: Repeat the above steps until the underwater operation is completed. Then, stop the positive and negative pressure of the air pump and vacuum pump in the entire underwater robot and control the underwater robot to retract.

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