Automatic positioning device and method for underwater laser cladding

Abstract

The invention relates to an automatic positioning device and method for underwater laser cladding, in particular to a sonar positioning and visual identification combined high-precision automatic positioning device and method, 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, so that 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. And meanwhile, under the assistance of the underwater moving trolley and the six-axis robot, the welding gun can be rapidly moved to a welding target area, the inertial navigation unit can feed back the position and posture of the welding gun in real time, and the welding gun can be adjusted more conveniently. The device can accurately position the repair position and improve the efficiency and accuracy of underwater operation.

Description

Technical Field

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

[0002] As an emerging material repair and remanufacturing method, underwater laser cladding technology has the advantages of high efficiency, precision and environmental protection, and is widely used in marine engineering, ship repair and oil platforms. However, the underwater environment is complex. When underwater materials have defects in a certain area, the materials need to be repaired in time to avoid serious losses. A major challenge in underwater laser cladding is how to accurately and efficiently find the damaged area. Factors such as limited underwater vision, refraction of light beams, water flow, stability of welding equipment underwater, and instability of sensor feedback will hinder the precise positioning of underwater welding. However, traditional positioning methods are difficult to meet the high-precision requirements required for laser cladding.

[0003] To solve the above problems, the present 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, which can monitor the position of the welding gun in real time, determine the relative position of the welding gun and the damaged area and make dynamic adjustments, which will significantly improve the accuracy and efficiency of underwater laser cladding. Through the present invention, the quality of underwater repair can be improved, and the application scope of underwater laser cladding can be broadened. Summary of the invention

[0004] Aiming at the problems of slow positioning speed and insufficient precision of existing underwater laser cladding, the present invention provides an automatic positioning device and method for underwater laser cladding.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] An automatic positioning device and method for underwater laser cladding, characterized in that it mainly comprises 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 comprises a sonar sensor (1) and a sonar fixing rod (2), the fixing rod (2) is connected to a circular fixing bracket (5) via a screw rod (6), and the sonar sensors are evenly distributed on the circular bracket. The system uses the propagation characteristics of sound waves in water to calculate the position information of the underwater operation area by transmitting sound waves and receiving reflected sound waves. The sonar transmitter transmits sound waves of a specific frequency, the sonar receiver receives the reflected sound waves, and the signal processor calculates the position of the operation area according to the propagation time of the sound waves.

[0008] The visual recognition system comprises an underwater camera (3) and a camera fixing bracket (4), wherein the camera (3) is connected to a customized fixing bracket (4), and the fixing bracket (4) is connected to a circular fixing bracket (5) via a screw rod (6). The system captures image information of an underwater operation area through a camera, uses image processing technology to identify feature points of the operation area, and assists a sonar positioning system in performing precise positioning.

[0009] The inertial navigation unit comprises an accelerometer, a gyroscope and a data processing unit. Three identical modules are fixed on the welding gun through a self-made special fixing clip (8), and the real-time status of the welding gun is fed back in multiple directions. The data processing unit integrates multi-source data to optimize the positioning result.

[0010] The motion system mainly comprises an intelligent omnidirectional trolley (9), a six-axis robot (10), a servo motor and a welding gun positioning mechanism. The welding gun fixture is fixed on the robot's mechanical arm. The robot is installed on the trolley. According to the position information provided by the sonar positioning system, the visual recognition system and the inertial navigation unit, the welding gun is controlled to move and position accurately in the underwater operation area.

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

[0012] The automatic positioning device and method for underwater laser cladding are characterized in that the inertial navigation unit (7) can provide continuous motion state information of the welding gun, including position, speed and posture, thereby enhancing the continuity and stability of positioning. The inertial navigation unit (7) transmits the signal to the intelligent omnidirectional trolley (9) and the load-bearing six-axis robot (10) after fusing and processing the multi-source data, and then controls the movement of the robot's mechanical arm to move the welding gun to a suitable 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 automation level of the operation; in addition, the device can work in a complex underwater environment, 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 are characterized by comprising the following steps:

[0015] Step 1: deploy the underwater laser cladding automatic positioning device to the target working waters to ensure the stability and operability of the equipment; start the power supply and perform a preliminary system self-check to ensure that key components such as the sonar positioning system (1), the visual recognition system (3), the inertial navigation unit (7) and the control system (12) are functioning normally.

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

[0017] Step three, 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 according to the characteristics of the target area and the welding requirements, and considers the optimal laser irradiation angle and scanning speed.

[0018] Step 4: The intelligent omnidirectional vehicle (9) and the six-axis robot (10) move the welding gun to a 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 movement state of the welding gun, and dynamically adjusts the welding gun position and laser emission angle in combination with 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 fed back by the sonar positioning and visual recognition systems, updates the target position and environmental status. If position deviation or environmental change is detected, the control processor immediately adjusts the motion trajectory of the welding gun and the laser output to ensure continuous and accurate welding.

[0020] The beneficial effects of the present invention are:

[0021] 1. The automatic positioning device proposed by the present invention integrates a sonar positioning system, a visual recognition system and an inertial navigation unit, and can achieve multi-point real-time synchronous positioning in a dynamic underwater environment. The sonar provides rough distance information, while the visual recognition system can accurately confirm the target workpiece during the actual welding process. The high-frequency data update of the inertial navigation unit can avoid system drift and ensure high position accuracy during the welding process.

[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 gun in time to cope with the influence of water flow, floating objects or other sudden factors, ensure the stability and consistency of the welding process, and thus greatly improve 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, and reduces welding defects such as pores, cracks and burn-throughs. At the same time, the real-time adjustment capability of the system makes the control of the heat-affected zone more effective, thereby extending the service life of the repaired parts. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

[0028] Explanation of the numbers in the figure: 1. Sonar locator; 2. Sonar fixing rod; 3. Underwater camera; 4. Fixing clamp rod; 5. Circular fixing device; 6. Adjustable screw; 7. Inertial navigation unit; 8. Fixing clamp; 9. Intelligent omnidirectional car; 10. Six-axis robot; 11. Data processing system; 12. Control system; 13. Communication system; 14. Laser generator; 15. Automatic wire feeder; 16. Shielding gas. DETAILED DESCRIPTION

[0029] The present invention relates to an automatic positioning device and method for underwater laser cladding, and the present invention is further described in detail below through drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0030] Figure 1 It is a specific embodiment of the present invention. The figure shows an automatic positioning device for underwater laser cladding. The device is designed for complex underwater environments. The underwater defects are accurately located by the automatic positioning device in the figure, and then the target area is welded according to the parameters set according to the type of defects. The device is characterized by integrating the sonar positioning device and the visual recognition system. When the sonar sensor finds the preliminary target area, the visual recognition system can immediately take a photo of the area and transmit it to the data processing system to identify the target area, which greatly improves the efficiency of positioning.

[0031] Figure 2 It is the main positioning structure of the device, and is composed 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 The inertial navigation unit is composed of an inertial navigation device (7) and a fixing clamp (8), and 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 the device includes an intelligent omnidirectional trolley (9) and a six-axis robot (10). After the positioning system and the inertial navigation unit complete the data analysis, they feed back to the control system. After the motion system receives the signal command from the control system, the trolley and the robot move the welding gun to the target area and place the welding gun at a suitable welding position.

[0032] In the embodiment, the underwater environment is special (water pressure, cooling rate, etc.). To ensure that the molten pool is fully melted, the laser power needs to be higher than normal compared to conventional laser cladding. The laser power in this embodiment 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 pointed out that a person skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be regarded as within the protection scope 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 comprises a sonar sensor (1) and a sonar fixing rod (2), wherein the sensor and the fixing rod are connected via a nut, and the sensor is fixed on a clamp at the bottom of a welding gun. Three identical sonar sensors are evenly distributed on a circular fixing device (5), and the sonar sensor feeds back detection data to a computer of a control system, and then the welding gun is moved to the approximate position of the defect via a motion system. The visual recognition system comprises an underwater camera (3) and a fixed clamp rod (4), wherein the camera is fixed on the clamp rod, and the fixed clamp rod (4) is connected to a circular fixing device (5) via a nut (6). Similarly, three cameras are evenly distributed on the circular fixing device and staggered with the sonar sensor. The sonar sensor, the camera and the welding gun move synchronously. When the welding gun moves to a roughly defective area, the camera takes a photo and transmits it to a data analysis system for further identification of the defect. The motion system comprises an intelligent omnidirectional trolley (9) and a six-axis robot (10). The advantage of the intelligent omnidirectional trolley is that it can move in all directions. With the rotation of the mechanical arm of the six-axis robot (10), the position of the welding gun can be adjusted 360 degrees without dead angles. The six-axis robot is fixed on the intelligent omnidirectional trolley. The mobile trolley can move to a specified 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 posture of the welding gun through the movement of the mechanical arm. The inertial navigation unit (7) installed on the welding gun can provide real-time feedback on the position of the welding gun.

2. The automatic positioning device and method for underwater laser cladding according to claim 1, characterized in that: The three sonar sensors are evenly distributed on the circular fixture. The advantage is that the sensors can cross-sensitize each other to improve the accuracy of positioning. The sensors send out sound wave signals to the surroundings, which are then fed back to the data processing system for a preliminary positioning.

3. The automatic positioning device and method for underwater laser cladding according to claim 1, characterized in that: The visual recognition system can be linked with the sonar sensor to record the conditions of the underwater welding area in real time. The camera takes pictures of the area and transmits them to the data processing center and control system for further analysis of the defects in the area. The wire feeding speed and the flow rate of the shielding gas are controlled according to the type of defects.

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 car. After the data from the sonar device is transmitted to the control system, the control system controls the motion trajectory of the intelligent omnidirectional car based on the feedback information. The intelligent car cooperates with the mechanical arm of the six-axis robot to place the welding gun in the appropriate welding position to ensure 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: The specific steps include: Step 1: a sonar sensor (1) emits a sound wave signal, and the ultrasonic wave is fed back to the sensor after encountering a defect. The detector records the time when the sound wave returns, and then transmits the data to a data processing system (11). The target distance is calculated based on the propagation speed and time of the ultrasonic wave in water, so as to determine the approximate location of the detection target area; Step 2: The underwater camera (3) and the sonar sensor (1) are at the same position. After the sonar sensor completes the initial positioning, the welding gun is moved to the target area with the assistance of the motion system (9, 10). The camera then 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 of the sonar positioning system (1) and the visual recognition system (3), and provides real-time feedback on the position and posture of the welding gun to further optimize the positioning result; Step 4, transmitting the optimized positioning result to the control system (12), and 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 result, and the two cooperate to move the welding gun to a suitable welding position; Step 5. After the final position 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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