Multi-degree-of-freedom mechanical arm cutting system for underwater operation and control method thereof
By using a multi-degree-of-freedom robotic arm cutting system, combined with aluminum profiles and pulleys to stabilize the movement of the gantry plate, and using a high-torque waterproof brushless motor and a stepper motor to drive the lead screw, precise motion control and stall detection are achieved. This solves the problems of insufficient flexibility and precision of underwater cutting equipment and improves the efficiency and stability of underwater cutting.
Patent Information
- Application Number
- CN202511336965.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-18
- Publication Date
- 2025-11-04
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Existing underwater cutting technology and equipment are limited in flexibility and have low integration, making it difficult to adapt to diverse task requirements. Furthermore, they lack control precision in complex underwater environments and are prone to decline in cutting efficiency and quality due to water flow interference and pressure changes.
A multi-degree-of-freedom robotic arm cutting system was designed, which uses aluminum profiles and pulleys to stabilize the movement of the gantry plate. It combines a high-torque waterproof brushless motor and a stepper motor to drive the lead screw. An abnormal motor current is detected by a detection device to achieve precise motion control and prevent stalling. The system also incorporates intelligent control algorithms to compensate for the impact of the underwater environment.
It improves the precision and efficiency of underwater cutting operations, and the robotic arm can flexibly adapt to complex environments, ensuring the stability and consistency of the cutting path and avoiding equipment damage.
Smart Images
Figure CN120886281A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of underwater operation, in particular to a multi-degree-of-freedom mechanical arm cutting system for underwater operation and a control system thereof. BACKGROUND
[0002] Underwater operation is widely used in fields such as ocean engineering, energy development, rescue and salvage, and scientific research. In the prior art, although underwater cutting technology has developed special equipment such as plasma cutting and laser cutting, these technologies usually rely on complex platforms and manual operation, which not only has high operation difficulty, but also limits the flexibility of the equipment. In the face of cutting and disassembly operations, underwater mechanical arms become important tools due to their flexibility and efficiency.
[0003] Currently, there are some schemes for modifying underwater mechanical arms, but these schemes are often limited to basic operation functions and do not fully consider the special needs of underwater operations. First, the integration of the device and the mechanical arm is not high, and there is a lack of modular design, which leads to poor adaptability between different mechanical arms. This not only increases the use threshold of the equipment, but also reduces the flexibility of the operation, making it difficult to meet the diverse task requirements. Second, the existing cutting device has insufficient control precision in complex underwater environments. Influenced by factors such as water flow interference and pressure changes, problems such as feed stall may occur, directly leading to a decrease in cutting efficiency and quality.
[0004] Therefore, in view of the above status, it is urgent to develop a multi-degree-of-freedom mechanical arm cutting system for underwater operation to overcome the deficiencies in current practical applications. SUMMARY
[0005] The purpose of the embodiments of the present application is to provide a multi-degree-of-freedom mechanical arm cutting system for underwater operation and a control method thereof, aiming to solve the problems raised in the background art.
[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: A multi-degree-of-freedom mechanical arm cutting system for underwater operation, comprising a mechanical arm and a connecting plate, a camera is cooperatively arranged on the mechanical arm, the mechanical arm and the connecting plate are fixedly connected through a plurality of uniformly distributed clamps, one end of an aluminum profile fixedly connected with the connecting plate, one end of the aluminum profile fixedly connected with a first fixing frame, the other end of the aluminum profile fixedly connected with a second fixing frame, and a feeding assembly cooperatively arranged between the first fixing frame and the second fixing frame, a gantry plate fixedly connected to the feeding assembly, a third mounting frame fixedly connected to one end surface of the gantry plate, a brushless motor fixedly connected to the third mounting frame, a cutting blade fixedly arranged on the drive end of the brushless motor, a plurality of fixed shafts symmetrically distributed about the aluminum profile fixedly connected to the other end of the gantry plate, a pulley rotatably sleeved to the other end of each fixed shaft, and the pulleys are in sliding connection with the track grooves on the aluminum profile.
[0007] Further technical solutions, the brushless motor adopts a large torque waterproof brushless motor.
[0008] Further technical solutions, the feeding assembly includes a stepper motor, a lead screw and a fixed seat; The stepper motor is fixedly installed below the second fixed frame; The fixed seat is fixedly connected to the third mounting frame, and the fixed seat is fixedly connected to the gantry plate; The inner wall of the fixed seat is threadedly connected with the lead screw; The upper end of the lead screw is rotatably connected with the first fixed frame; The lower end of the lead screw is fixedly connected with the driving end of the stepper motor.
[0009] Further technical solutions, a shaft coupling is arranged between the driving end of the stepper motor and the lead screw.
[0010] Further technical solutions, further comprising a controller and a detection device, the stepper motor is electrically connected with the detection device, and the controller is electrically connected with the stepper motor, the brushless motor and the detection device.
[0011] In addition, the application also provides a control method of the multi-degree-of-freedom mechanical arm cutting system for underwater operation, which is based on the multi-degree-of-freedom mechanical arm cutting system for underwater operation, and specifically includes the following steps: S1: initialization calibration, which is divided into camera calibration and mechanical arm calibration; S2: identify the target object and calculate the position of the target in the camera coordinate system; S3: convert the position of the target in the image into the position in the mechanical arm base coordinate system; S4: according to the target position and the current position of the mechanical arm, calculate the motion path and joint angle that the mechanical arm needs to execute; S5: according to the planned path, control each joint of the mechanical arm to move to the target position, and control the end effector of the mechanical arm to grasp the target; S6: complete the grasping and subsequent operation.
[0012] Further technical solutions, the motion planning of the mechanical arm in S4 is inverse kinematics solution, and the process is as follows: (1) record the target position as , (2) record the current position of the end effector of the mechanical arm as ; ； ; (3) write the objective function, execute the loop until the objective function ; ; ; ; ; ; (4) Jacobian matrix is constructed by partial derivative, and the pseudo-inverse of the Jacobian matrix links the end effector position coordinates and the joint angle vector; ； ; ; (5) iteration is carried out by Newton method until the objective function meets the convergence condition; ; ; ; (6) return to step (2) until the loop converges.
[0013] Compared with the prior art, the embodiment of the application has the following beneficial effects: 1. The target object is grabbed by the mechanical arm, the moving path of the gantry plate is stabilized in a manner that the aluminum profile and the pulley are matched, deviation caused by vibration or resistance of the underwater environment is avoided, the step motor drives the coupling to rotate, then the coupling drives the lead screw to rotate, then the lead screw drives the fixed seat to advance, then the fixed seat drives the gantry plate and the third mounting frame to advance, then the third mounting frame drives the brushless motor and the cutting piece to advance, then the cutting piece cuts the target object, the integration is high, the strip-shaped target can be efficiently grabbed and cut, and the precision and efficiency of underwater cutting operation are greatly improved; 2. The multi-degree-of-freedom design of the mechanical arm enables it to flexibly adapt to complex underwater environments and accurately position and operate the cutting tool through precise motion control; 3. The detection device detects whether the current of the step motor abnormally rises, so as to judge whether the step motor is blocked, and then the working state of the step motor is adjusted in time to avoid damage to the device caused by overload; 4. Precise motion control is used to accurately position and operate the cutting system, especially when facing the complex factor of water flow fluctuation, the mechanical arm effectively compensates for the influence of the complex underwater environment on the operation process by combining intelligent control algorithm, and ensures the stability of the cutting path and the consistency of the cutting quality.
[0014] In order to more clearly illustrate the structural features and effects of the application, the application will be described in detail below with reference to the drawings and specific embodiments. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 is a perspective view of the application from another angle; Figure 2 is a perspective view of the application from another angle; Figure 3 is a perspective view of the application from another angle; Figure 2 is an enlarged perspective view of part A in the application; Figure 4 is a flow chart of the working process of the current signal detection module of the application; Figure 5 is a flow chart of the linkage control of the application; Figure 6 is a visual servo control block diagram of the application.
[0016] In the figure: 1, first fixed frame; 2, second fixed frame; 3, aluminum profile; 4, stepping motor; 5, third mounting bracket; 6, brushless motor; 7, connecting plate; 8, cutting piece; 9, hoop; 10, mechanical arm; 11, shaft coupling; 12, lead screw; 13, gantry plate; 14, pulley; 15, fixed shaft; 16, fixed seat. DETAILED DESCRIPTION
[0017] In order to make the purpose, technical scheme and advantages of the application more clear and understandable, the application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the application and do not limit the application.
[0018] The specific implementation of the application is described in detail below in combination with specific examples.
[0019] As shown in Figures 1-3 , the embodiment of the application provides a multi-degree-of-freedom mechanical arm cutting system for underwater operation, which comprises a mechanical arm 10 and a connecting plate 7, a camera is arranged on the mechanical arm 10 in cooperation, the mechanical arm 10 and the connecting plate 7 are fixedly connected through a plurality of uniformly distributed hoops 9, one end of the connecting plate 7 is fixedly connected with an aluminum profile 3, one end of the aluminum profile 3 is fixedly connected with a first fixed frame 1, the other end of the aluminum profile 3 is fixedly connected with a second fixed frame 2, and a feeding assembly is arranged between the first fixed frame 1 and the second fixed frame 2 in cooperation, the gantry plate 13 is fixedly connected to the feeding assembly, the third mounting bracket 5 is fixedly connected to one end surface of the gantry plate 13, the brushless motor 6 is fixedly connected to the third mounting bracket 5, the cutting piece 8 is fixedly arranged on the driving end of the brushless motor 6, a plurality of fixed shafts 15 are fixedly connected to the other end of the gantry plate 13 and are symmetrically distributed about the aluminum profile 3, the pulleys 14 are rotatably sleeved to the other ends of the fixed shafts 15, and the pulleys 14 are slidably connected to the track grooves on the aluminum profile 3.
[0020] Further, the brushless motor 6 adopts a large torque waterproof brushless motor.
[0021] As shown in Figures 1-3 The feeding assembly comprises a stepping motor 4, a lead screw 12 and a fixed seat 16; the stepping motor 4 is fixedly installed on the second fixed frame 2; the fixed seat 16 is fixedly connected on the third fixed frame 5 and is fixedly connected with the gantry plate 13; the lead screw 12 is threadedly connected on the inner wall of the fixed seat 16; the upper end of the lead screw 12 is rotatably connected with the first fixed frame 1; and the lower end of the lead screw 12 is fixedly connected with the driving end of the stepping motor 4.
[0022] Further, a shaft coupling 11 is arranged between the driving end of the stepping motor 4 and the lead screw 12.
[0023] In specific application, the stepping motor 4 is started, then the stepping motor 4 drives the lead screw 12 to rotate through the shaft coupling 11, then the fixed seat 16 is driven to advance or retreat by the lead screw 12, and then the gantry plate 13 and the third fixed frame 5 are driven to advance or retreat by the fixed seat 16.
[0024] Further, a controller (not shown in the figure) and a detection device (not shown in the figure) are further included; the stepping motor 4 is electrically connected with the detection device; the controller is electrically connected with the stepping motor 4, the brushless motor 6 and the detection device; the detection device is used for detecting whether the current of the stepping motor 4 is abnormally increased, so as to determine whether the stepping motor 4 is stalled, and then timely adjust the working state of the stepping motor 4.
[0025] In specific application, when it is detected that the running current of the stepping motor 4 is abnormally increased (indicating that the feeding is stalled), the controller will automatically stop the stepping motor 4 from running, and send a pause signal to the brushless motor 6; after a certain time delay, the stepping motor 4 is restarted to continue feeding until the cutting is completed.
[0026] In the embodiment of the application, the target object is grabbed by the mechanical arm 10, the movement path of the gantry plate 13 is stabilized by the cooperation of the aluminum profile 3 and the pulley 14, the deviation caused by the vibration or resistance of the underwater environment is avoided, the coupling 11 is rotated by the stepper motor 4, then the lead screw 12 is rotated by the coupling 11, then the fixed seat 16 is advanced by the lead screw 12, then the gantry plate 13 and the third mounting frame 5 are advanced by the fixed seat 16, then the brushless motor 6 and the cutting blade 8 are advanced by the third mounting frame 5, and then the cutting blade 8 cuts the target object, the degree of integration is high, the strip-shaped target can be efficiently grabbed and cut, and the precision and efficiency of the underwater cutting operation are greatly improved; the multi-degree-of-freedom design of the mechanical arm 10 enables it to flexibly adapt to complex underwater environments and accurately position and operate the cutting tool through precise motion control; whether the current of the stepper motor 4 abnormally rises is detected by the detection device, so as to judge whether the stepper motor 4 is blocked, and then the working state of the stepper motor 4 is adjusted in time to avoid damage to the device due to overload.
[0027] The working principle of the application is that the target object is grabbed by the mechanical arm 10, the stepper motor 4 is started, then the lead screw 12 is rotated by the coupling 11, then the fixed seat 16 is advanced by the lead screw 12, then the gantry plate 13 and the third mounting frame 5 are advanced by the fixed seat 16, then the brushless motor 6 and the cutting blade 8 are advanced by the third mounting frame 5, and then the cutting blade 8 cuts the target object.
[0028] As shown in the accompanying drawings, Figures 1-6 The application also provides a control method of the multi-degree-of-freedom mechanical arm cutting system for underwater operation, which is based on the above-mentioned multi-degree-of-freedom mechanical arm cutting system for underwater operation and specifically includes the following steps: S1: initialization calibration; Camera calibration: the mapping relationship between the image coordinate system and the physical coordinate system is established by calibrating the internal and external parameters of the camera; mechanical arm calibration: the corresponding relationship between the mechanical arm base coordinate system and the end effector pose is established through joint encoder feedback.
[0029] Specifically, the initialization calibration includes camera calibration and mechanical arm 10 calibration. The camera calibration ensures that the internal and external parameters of the camera are accurate, so that the depth and position information can be accurately extracted from the image; the mechanical arm 10 calibration ensures that the positions of each joint of the mechanical arm can be accurately controlled and fed back.
[0030] S2: target recognition and positioning; Specifically, first image acquisition: using a camera to obtain the image of the working area; second target detection: identifying the target object through image processing algorithms (such as object detection, feature matching, etc.), and extracting feature points; finally target positioning: calculating the two-dimensional (or three-dimensional) position of the target in the camera coordinate system according to the detected target position.
[0031] S3: Coordinate transformation: First, convert from the image coordinate system to the base coordinate system of the robot arm 10, and then use the parameters obtained through camera calibration and some geometric transformations to convert the position of the target in the image to the position in the base coordinate system of the robot arm.
[0032] S4: Motion planning; According to the target position and the current position of the robot arm 10, calculate the motion path and joint angle that the robot arm 10 needs to execute.
[0033] Specifically, the motion planning algorithm uses a method combining the pseudo-inverse method based on the Jacobian matrix and the Newton method iteration to perform inverse kinematics calculation for the motion planning of the robot arm 10. The process is as follows: (taking two dimensions as an example) (1) Let the target position be , (2) Let the current position of the end effector of the robot arm 10 be ; Specifically, ； ; (3) Write the objective function, and execute the loop until the objective function ; ; ; ; ; ; (4) Construct the Jacobian matrix through the partial derivative, and the pseudo-inverse of the Jacobian matrix relates the end effector position coordinates to the joint angle vector; ； ; ; (5) Perform iteration through the Newton method until the objective function meets the convergence condition; ; ; ; (6) return to step (2) until the loop converges.
[0034] S5: perform the grabbing: According to the planned path, the joints of the robot arm 10 are moved to the target position, and when the robot arm 10 reaches the target position, the end effector is controlled to perform the grabbing.
[0035] Specifically, visual feedback and adjustment are needed during the movement of the robot arm 10; images are continuously acquired, the error between the target position and the actual position of the robot arm 10 is monitored, and through visual feedback, the movement path of the robot arm is adjusted in real time to ensure accurate arrival at the target position.
[0036] S6: complete the grabbing and subsequent operations.
[0037] The item is confirmed to have been successfully grabbed through other sensing means such as force sensors, and according to the needs, the robot arm 10 will perform a cutting operation.
[0038] The circuits, electronic components and modules involved are all prior art, and those skilled in the art can implement them without further description. The content protected by the present application does not involve improvement of software and methods.
[0039] The above only describes the preferred embodiments of the present application and does not limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A multi-degree-of-freedom robotic arm cutting system for underwater operations, comprising a robotic arm (10) and a connecting plate (7), wherein a camera is mounted on the robotic arm (10), characterized in that... The robotic arm (10) and the connecting plate (7) are fixedly connected by a plurality of evenly distributed clamps (9). An aluminum profile (3) is fixedly connected to the other end of the connecting plate (7). A first fixing frame (1) is fixedly connected to one end of the aluminum profile (3), and a second fixing frame (2) is fixedly connected to the other end of the aluminum profile (3). A feeding component is provided between the first fixing frame (1) and the second fixing frame (2). A gantry plate (13) is fixedly connected to the feeding component. A third mounting frame (5) is fixedly connected to one end face of the gantry plate (13). A brushless motor (6) is fixedly connected to the third mounting frame (5). A cutting blade (8) is fixedly provided at the drive end of the brushless motor (6). A plurality of fixed shafts (15) symmetrically distributed about the aluminum profile (3) are fixedly connected to the other end of the gantry plate (13). A pulley (14) is rotatably sleeved at the other end of each fixed shaft (15), and the pulley (14) is slidably connected to the track groove on the aluminum profile (3).
2. The underwater multi-degree-of-freedom robotic arm cutting system according to claim 1, characterized in that, The brushless motor (6) adopts a high-torque waterproof brushless motor.
3. The underwater multi-degree-of-freedom robotic arm cutting system according to claim 1, characterized in that, The feed assembly includes a stepper motor (4), a lead screw (12), and a fixed base (16). The second mounting bracket (2) has a stepper motor (4) fixedly installed on its upper and lower sides; the third mounting bracket (5) has a fixed seat (16) fixedly connected to it, and the fixed seat (16) is fixedly connected to the gantry plate (13). The inner wall of the fixed seat (16) is threaded with a lead screw (12). The upper end of the lead screw (12) is rotatably connected to the first mounting bracket (1), and the lower end of the lead screw (12) is fixedly connected to the drive end of the stepper motor (4).
4. The underwater multi-degree-of-freedom robotic arm cutting system according to claim 3, characterized in that, A coupling (11) is provided between the drive end of the stepper motor (4) and the lead screw (12).
5. The underwater multi-degree-of-freedom robotic arm cutting system according to claim 4, characterized in that, It also includes a controller and a detection device. The stepper motor (4) is electrically connected to the detection device, and the controller is electrically connected to the stepper motor (4), the brushless motor (6) and the detection device respectively.
6. A control method for a multi-degree-of-freedom robotic arm cutting system for underwater operations, based on the multi-degree-of-freedom robotic arm cutting system for underwater operations as described in any one of claims 1-5, characterized in that, Specifically, the following steps are included: S1: Initial calibration, which is divided into camera calibration and robotic arm (10) calibration; S2: Identify the target object and calculate its position in the camera coordinate system; S3: Convert the position of the target in the image to the position in the base coordinate system of the robotic arm (10); S4: Based on the target position and the current position of the robotic arm (10), calculate the motion path and joint angles that the robotic arm (10) needs to execute; S5: According to the planned path, control each joint of the robotic arm (10) to move to the target position, and then control the end effector of the robotic arm (10) to grasp the target; S6: Complete the capture and subsequent operations.
7. The control method for a multi-degree-of-freedom robotic arm cutting system for underwater operations according to claim 6, characterized in that, S5 continuously acquires images and monitors the error between the target position and the actual position of the robotic arm (10). Through visual feedback, it adjusts the motion path of the robotic arm in real time.
8. The control method for a multi-degree-of-freedom robotic arm cutting system for underwater operations according to claim 6, characterized in that, The motion planning of the robotic arm (10) in S4 is performed using inverse kinematics, and the process is as follows: (1) Record the target location as ; (2) Let the current position of the end effector of robotic arm 10 be _____. ; ； ； (3) Write out the objective function and execute the loop until the objective function is reached. ; ； ； ； ； ； (4) Construct the Jacobian matrix through partial derivatives, and use the pseudo-inverse of the Jacobian matrix to link the position coordinates of the end effector with the angle vectors of each joint; ； ； ； (5) Iterate using Newton's method until the objective function satisfies the convergence condition; ； ； ； (6) Return to step (2) until the loop converges.