| The laying methods of pressure pipelines are mainly overhead and buried,and some even have a coating layer.Testing the pipeline requires high-altitude operations,excavation,and dismantling of the coating layer.In order to cope with complex testing environments and meet the requirements of pressure pipeline testing,this article has developed a portable pressure pipeline welding seam internal detection system.The main work of this article is as follows:(1)On the basis of advanced detection methods and mobile robot technology research,this article proposes using robots as mobile carriers,equipped with ultrasonic phased array,electromagnetic ultrasonic thickness measurement,and camera detection equipment.The robot is remotely controlled to enter the pipeline for detection through a control box.According to the demand analysis,the robot is designed as an integrated body structure,paired with four magnetic adsorption wheels,and adopts a dual motor front drive design mode.To improve the anti-interference ability of the motor system,a cascade PID controller was adopted,and the PI control algorithm was verified through simulation testing,which has a good control effect on the motor speed.(2)Based on the analysis of testing requirements and technical requirements for testing modules,carry out the design of testing institutions.This system uses high-definition cameras,portable electromagnetic ultrasonic thickness gauges,and phased array ultrasonic flaw detectors as the detection execution mechanisms.Modular design of each detection unit and design of the mounting method of the detection device.Based on a dual motor driven robot,research was conducted on spatial displacement and position calculation,and robot pipeline positioning experiments were conducted.30 sets of true trajectory position coordinates and 30 sets of algorithm calculated position coordinates were taken,and their motion trajectories were simulated using Origin software.The results showed that the two trajectories basically overlapped,with an average error of less than 3.5%,verifying the reliability of the positioning algorithm.(3)The design of the robot remote control system adopts an upper and lower computer control mode.The upper computer is responsible for issuing control commands and collecting and processing detection data,while the lower computer is used to execute control commands sent by the upper computer.The hardware modules related to robot communication and control are integrated into the control box,which is connected to the robot through wired means.A handheld device supporting wireless communication is designed.(4)Using Visual Studio software,develop the upper computer software based on the C#/WPF framework,and design the lower computer software based on Twin CAT3 from Beifu Company.Carry out system communication design,and choose Twin CAT.ADS communication mode between industrial computer and motion controller;The electromagnetic ultrasonic thickness gauge and phased array ultrasonic flaw detector communicate with the industrial computer based on TCP/IP protocol;To achieve upper computer access to gyroscope data,Mod Bus gateway is used to convert Mod Bus TCP protocol to Mod Bus RTU protocol.(5)Perform functional testing on the detection system.In the preparation stage,three defects were buried on the left side of the weld seam at the end of the test sample tube,followed by robot travel speed test,90 ° bending test,remote macroscopic inspection,ultrasonic phased array inspection,and pipeline wall thickness inspection.The test results indicate that this detection system can meet the requirements of pressure pipeline detection. |
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