An automatic positioning device and method for underwater laser cladding

Abstract

The application relates to an automatic positioning device and method for underwater laser cladding, in particular to a high-precision automatic positioning device and method combining sonar positioning and visual identification, which comprises a sonar positioning system, a visual identification system and an inertial navigation unit. The sonar positioning system and the visual identification system are fixed on the same circular fixing device, and synchronous positioning analysis can be realized. The inertial navigation unit fuses multi-source data, optimizes positioning parameters on the basis of sonar positioning, and obtains more accurate position information. Meanwhile, under the assistance of an underwater moving trolley and a six-axis robot, the welding gun can be quickly moved to a welding target area, and the inertial navigation unit can also feed back the position and posture of the welding gun in real time, so that the welding gun is more convenient to adjust. The device can accurately position a repair position, and improves the efficiency and accuracy of underwater operation.

Description

Technical Field

[0001] This invention relates to the field of automatic positioning technology in laser welding, and in particular to a high-precision positioning device and method based on a combination of sonar sensing and visual recognition to achieve automatic positioning. Background Technology

[0002] Underwater laser cladding technology, as an emerging method for material repair and remanufacturing, boasts advantages such as high efficiency, precision, and environmental friendliness, and is widely used in marine engineering, ship repair, and oil platforms. However, the underwater environment is complex. When defects appear in a certain area of ​​underwater materials, timely repair is necessary to avoid serious losses. A major challenge in underwater laser cladding is accurately and efficiently locating the damaged area. Factors such as limited underwater vision, beam refraction, water flow, the stability of welding equipment underwater, and the instability of sensor feedback all hinder precise positioning in underwater welding. Traditional positioning methods are insufficient to meet the high precision requirements of laser cladding.

[0003] To address the aforementioned problems, this invention provides an automatic positioning device and method for underwater laser cladding. The device includes a sonar positioning system, a visual recognition system, and an inertial navigation unit, capable of real-time monitoring of the welding torch position, determining the relative position of the welding torch to the damaged area, and making dynamic adjustments. This significantly improves the accuracy and efficiency of underwater laser cladding. This invention can improve the quality of underwater repair and broaden the application scope of underwater laser cladding. Summary of the Invention

[0004] This invention addresses the problems of slow positioning speed and insufficient accuracy in existing underwater laser cladding systems by providing an automatic positioning device and method for underwater laser cladding.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An automatic positioning device and method for underwater laser cladding, characterized in that it mainly includes a sonar positioning system (1), a visual recognition system (3), an inertial navigation unit (7), an intelligent omnidirectional vehicle (9), a six-axis robot (10), a control system (12), a laser generator (14), an automatic wire feeder (15), and a protective gas (16), wherein:

[0007] The sonar positioning system includes a sonar sensor (1) and a sonar mounting rod (2). The mounting rod (2) is connected to a circular mounting bracket (5) via a lead screw (6). The sonar sensors are evenly distributed on the circular bracket. This system utilizes the propagation characteristics of sound waves in water to calculate the location information of the underwater operation area by emitting sound waves and receiving the reflected sound waves. The sonar transmitter emits sound waves of a specific frequency, the sonar receiver receives the reflected sound waves, and the signal processor calculates the location of the operation area based on the propagation time of the sound waves.

[0008] The visual recognition system includes an underwater camera (3) and a camera mounting bracket (4). The camera (3) is connected to the customized mounting bracket (4), which is then connected to a circular mounting bracket (5) via a lead screw (6). The system captures image information of the underwater work area through the camera, uses image processing technology to identify feature points of the work area, and assists the sonar positioning system in accurate positioning.

[0009] The inertial navigation unit includes an accelerometer, a gyroscope, and a data processing unit. The three identical modules are fixed to the welding torch by a self-made special fixing clip (8). The real-time status of the welding torch is fed back from multiple directions. The data processing unit integrates multi-source data and optimizes the positioning results.

[0010] The motion system mainly includes an intelligent omnidirectional vehicle (9), a six-axis robot (10), a servo motor, and a welding torch positioning mechanism. The welding torch fixture is fixed on the robot's mechanical arm, and the robot is mounted on the vehicle. Based on the position information provided by the sonar positioning system, the visual recognition system, and the inertial navigation unit, the welding torch is controlled to move and position precisely in the underwater working area.

[0011] The automatic positioning device and method for underwater laser cladding is characterized in that the device integrates a sonar positioning system (1), a visual recognition system (3), an inertial navigation unit (7), and a motion system consisting of an intelligent omnidirectional vehicle (9) and a six-axis robot (10). The coordinated operation of these systems provides high-precision positioning capability. By utilizing the characteristics of sound waves propagating underwater, it can provide depth and distance information of the work area. The application of image processing technology can further identify the characteristics of defects in the work area and adopt different wire feeding speeds for welding different defects to improve welding quality.

[0012] The automatic positioning device and method for underwater laser cladding is characterized in that the inertial navigation unit (7) can provide continuous motion state information of the welding torch, including position, speed and attitude, which enhances the continuity and stability of positioning. The inertial navigation unit (7) fused and processed the multi-source data and transmitted the signal to the intelligent omnidirectional vehicle (9) and the six-axis robot (10), and then controlled the robot's mechanical arm to move the welding torch to the appropriate welding area.

[0013] The automatic positioning device and method for underwater laser cladding are characterized in that the device reduces manual operation and improves the level of automation; in addition, the device can work in complex underwater environments, adapt to different operating conditions and environmental changes, monitor the operating status in real time, and make adjustments based on feedback information to ensure the stability and reliability of the welding process.

[0014] The automatic positioning device and method for underwater laser cladding, characterized in that it specifically includes the following steps:

[0015] Step 1: Deploy the underwater laser cladding automatic positioning device to the target working water area to ensure the stability and operability of the equipment; turn on the power and perform a preliminary system self-test to ensure that key components such as the sonar positioning system (1), visual recognition system (3), inertial navigation unit (7) and control system (12) are working properly.

[0016] Step 2: Activate the sonar positioning system (1) to obtain preliminary location information of the target area in the underwater environment; combine with the visual recognition system (3) to capture images of the target area in real time, identify the boundary and shape of the workpiece through image processing algorithms, and accurately determine its orientation and distance; use the inertial navigation unit (7) to calibrate the position and orientation of the current device to improve positioning accuracy and prevent drift.

[0017] Step 3: The data processing system (11) receives and processes the positioning data from each sensor, generates a three-dimensional model of the welding path, optimizes the welding path based on the characteristics of the target area and welding requirements, and considers the best laser irradiation angle and scanning speed.

[0018] Step 4: The intelligent omnidirectional vehicle (9) and the six-axis robot (10) move the welding torch to the preset starting position to prepare for the laser cladding operation; start the laser, set the welding parameters (such as power, speed, etc.) according to the characteristics of the target area, and perform laser repair; the inertial navigation unit (7) provides real-time feedback on the motion status of the welding torch, and dynamically adjusts the position of the welding torch and the laser emission angle by combining data from the sonar and vision systems to ensure welding accuracy.

[0019] Step 5: The communication system transmits the final positioning information to the laser cladding system. During the welding process, it continuously receives information from the sonar positioning and visual recognition system to update the target position and environmental status. If a positional deviation or environmental change is detected, the control processor immediately adjusts the motion trajectory of the welding torch and the laser output to ensure continuous and accurate welding.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. The automatic positioning device proposed in this invention integrates a sonar positioning system, a visual recognition system, and an inertial navigation unit, enabling multi-point real-time synchronous positioning in dynamic underwater environments. The sonar provides coarse distance information, while the visual recognition system accurately identifies the target workpiece during the actual welding process. The high-frequency data updates from the inertial navigation unit prevent system drift and ensure high positional accuracy during welding.

[0022] 2. The underwater laser cladding automatic positioning device of the present invention is equipped with a real-time feedback mechanism, which can quickly acquire and process sensor data to form a closed-loop control. The real-time feedback mechanism helps to adjust the position and direction of the welding torch in a timely manner to cope with the influence of water flow, floating objects or other sudden factors, ensuring the stability and consistency of the welding process, thereby significantly improving the welding quality.

[0023] 3. The underwater laser cladding automatic positioning device of the present invention ensures the uniformity and consistency of laser cladding through precise positioning and path control, reducing welding defects such as porosity, cracks and burn-through. At the same time, the system's real-time adjustment capability makes the control of the heat-affected zone more effective and extends the service life of the repaired parts. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of an automatic positioning device and method for underwater laser cladding provided by the present invention;

[0025] Figure 2 This is a schematic diagram of a sonar positioning and visual recognition system for an automatic positioning device and method for underwater laser cladding provided by the present invention;

[0026] Figure 3 This is a schematic diagram of the inertial navigation unit of an automatic positioning device and method for underwater laser cladding provided by the present invention;

[0027] Figure 4 This is a schematic diagram of the motion system of an automatic positioning device and method for underwater laser cladding provided by the present invention;

[0028] The numbers in the diagram are explained as follows: 1. Sonar locator; 2. Sonar mounting rod; 3. Underwater camera; 4. Fixing clamp; 5. Circular fixing device; 6. Adjustable screw; 7. Inertial navigation unit; 8. Fixing clamp; 9. Intelligent omnidirectional vehicle; 10. Six-axis robot; 11. Data processing system; 12. Control system; 13. Communication system; 14. Laser generator; 15. Automatic wire feeder; 16. Protective gas. Detailed Implementation

[0029] This invention relates to an automatic positioning device and method for underwater laser cladding. The invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0030] Figure 1 This is a specific embodiment of the present invention. The figure shows an automatic positioning device for underwater laser cladding. Designed for complex underwater environments, this device accurately locates underwater defects using the automatic positioning mechanism shown in the figure, and then welds the target area according to the type of defect set. The device's key feature is the integration of a sonar positioning device and a visual recognition system. While the sonar sensor locates the initial target area, the visual recognition system immediately captures a photograph of that area and transmits it to the data processing system for target area identification, significantly improving positioning efficiency.

[0031] Figure 2 This is the main positioning structure of the device, consisting of a sonar sensor (1), a sonar fixing rod (2), a camera (3), a camera bracket (4), and a circular fixing device (5); Figure 3 It is an inertial navigation unit, consisting of an inertial navigator (7) and a fixing clip (8). Its main function is to fuse multi-source data and optimize the data to obtain a more accurate position. Figure 4 The motion system of this device includes an intelligent omnidirectional vehicle (9) and a six-axis robot (10). After the positioning system and inertial navigation unit complete the data analysis, the data is fed back to the control system. After the motion system receives the signal command from the control system, the vehicle and the robot move the welding torch to the target area and place the welding torch in a suitable welding position.

[0032] In the embodiment, the underwater environment is special (water pressure, cooling rate, etc.). In order to ensure that the molten pool is fully melted, the laser power needs to be higher than that of conventional laser cladding. In this embodiment, the laser power is 3kW, the scanning speed is 600mm / min, the wire feeding speed is 1.6m / min, and the shielding gas flow rate is 20L / min. The welding parameters are adjusted in real time according to the information feedback from the visual recognition system.

[0033] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. An automatic positioning device and method for underwater laser cladding, characterized in that, It mainly includes a sonar positioning system (1), a visual recognition system (3), an inertial navigation unit (7), an intelligent omnidirectional vehicle (9), a six-axis robot (10), a data processing system (11), a control system (12), a communication system (13), a laser generator (14), an automatic wire feeder (15), and a protective gas (16); The sonar positioning system includes a sonar sensor (1) and a sonar fixing rod (2). The sensor and the fixing rod are connected by a nut to fix the sensor on the lower clamp of the welding gun. Three identical sonar sensors are evenly distributed on the circular fixing device (5). The sonar sensor feeds back the detection data to the computer of the control system, and then the welding gun is moved to the approximate location of the defect through the motion system. The visual recognition system includes an underwater camera (3) and a fixed clamp (4). The camera is fixed on the clamp, and the fixed clamp (4) is connected to a circular fixing device (5) by a nut (6). Similarly, three cameras are evenly distributed on the circular fixing device, staggered from the sonar sensor. The sonar sensor, camera and welding torch move synchronously. When the welding torch moves to the approximate defect area, the camera takes a picture and transmits it to the data analysis system for further identification of the defect. The motion system includes an intelligent omnidirectional vehicle (9) and a six-axis robot (10). The advantage of the intelligent omnidirectional vehicle is that it can move in all directions. With the rotation of the robotic arm of the six-axis robot (10), the position of the welding torch can be adjusted 360° without dead angles. The six-axis robot is installed and fixed on the intelligent omnidirectional vehicle. The mobile vehicle can move to the designated position under the control of the control system. At the same time, the control system transmits positioning information to the six-axis robot through the communication system. After receiving the information, the six-axis robot adjusts the position and attitude of the welding torch through the movement of the robotic arm. The inertial navigation unit (7) installed on the welding torch can provide real-time feedback on the position of the welding torch.

2. The automatic positioning device and method for underwater laser cladding according to claim 1, characterized in that: Three sonar sensors are evenly distributed on a circular fixed device. The advantage of this is that the sensors cross-sensing each other, which improves the positioning accuracy. The sensors emit sound wave signals to the surroundings, and the sound wave signals are then fed back to the data processing system for initial positioning.

3. The automatic positioning device and method for underwater laser cladding according to claim 1, characterized in that: The visual recognition system can work in conjunction with sonar sensors to record the underwater welding area in real time. The camera captures images of the area and transmits them to the data processing center and control system for further analysis of defects. Based on the type of defect, the wire feeding speed and the flow rate of the shielding gas are controlled.

4. The automatic positioning device and method for underwater laser cladding according to claim 1, characterized in that: The motion system consists of a six-axis robot and an intelligent omnidirectional vehicle. After the data from the sonar device is transmitted to the control system, the control system controls the movement trajectory of the intelligent omnidirectional vehicle based on the feedback information. The intelligent vehicle, in conjunction with the robotic arm of the six-axis robot, moves the welding torch to the appropriate welding position, ensuring the accuracy of the welding position.

5. The use of the automatic positioning device and method for underwater laser cladding according to claim 1, characterized in that, Specifically, the following steps are included: Step 1: The sonar sensor (1) emits a sound wave signal. When the ultrasonic wave encounters a defect, it is fed back to the sensor. The detector records the time when the sound wave returns and then transmits the data to the data processing system (11). The distance to the target is calculated by the speed and time of ultrasonic wave propagation in water, so as to determine the approximate location of the target area. Step 2: The underwater camera (3) and the sonar sensor (1) are in the same position. After the sonar sensor completes the initial positioning, the welding torch is moved to the target area with the assistance of the motion system (9, 10). Then the camera takes an image of the target area and transmits it to the data processing system (11) to identify the damaged area and eliminate interference from factors such as attachments. Step 3: The inertial navigation unit (7) integrates the data from the sonar positioning system (1) and the visual recognition system (3) to provide real-time feedback on the position and attitude of the welding torch, and further optimize the positioning results; Step 4: The optimized positioning results are transmitted to the control system (12). The control system (12) controls the movement of the intelligent omnidirectional vehicle (9) and the six-axis robot (10) mechanical arm according to the positioning results. The two work together to move the welding torch to the appropriate welding position. Step 5: After the final location is determined, the signal is transmitted to the laser cladding system to repair the damaged area. During the repair process, the wire feeding speed and laser power are controlled according to the type and size of the defect.

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