| Large diameter steel pipe is widely used in the transportation of oil and gas,and oil and gas transportation requires the same diameter of steel pipe welding to increase the length of steel pipe to complete the long-distance transmission,at the same time in the welding will be due to the geometric parameters of the two steel pipe end is not consistent,will use external forces to force it to weld,the two steel pipe weld will be cracked over time and the impact of the environment,which will cause Oil leaks and pollution of the environment.Therefo re,the accu rate measurement of the pipe ends by laser ranging has become the focus of domestic and international research.In this paper,a non-contact roundness inspection system based on the laser distance measuring principle is designed based on the study of steel pipe measurement methods.The laser displacement sensor IL-1000 from Keyence is used as the measurement tool and the geometric parameters of the tube end are fitted by combining the circumferential traversal principle and the least squares principle.The inspection system consists of a servo system,a Siemens PLC,a laser displacement sensor,an industrial control computer and a rotating measuring mechanism.Siemens PLC as the main control unit of the control servo system,control the servo system to realize the circumferential measurement of the tube end of the pipe,so as to get the displacement data,using the least squares circle fitting algorithm and the data reconstruction algorithm to fit the longest diameter,shortest diameter,average diameter,roundness and other information friendly display in the human-machine interface.The data processing and algorithm fitting as well as the software interface design were implemented using VS IDE,and the detected data were stored and uploaded to the database.F actors that may cause system errors are also analyzed,and countermeasures are proposed to reduce the errors caused by these factors.After several repetitive experiments on the built experimental platform,the final roundness detection accuracy of the system can reach 0.2mm.In order to verify the error caused by the deviation of the rotating measuring mechanism from the center of the steel pipe,and the relevant experiments were conducted to ensure that the results obtained from the inspection can be guaranteed within 0.2mm when the deviation from the horizontal coordinate of the center of the circle is plus or minus 15mm.The final results show that this system can achieve online,fast and high accuracy inspection.In practical application,in order to make the steel pipe pair welding,it is necessary to combine and sort the batches of steel pipes obtained from the inspection system,so that the steel pipes in the same batch are combined together in the best matching way,thus improving the utilization rate of the steel pipes and reducing the waste of the steel pipes.For the combination of steel pipe sorting problem is now classified as NP-Hard problem,for this problem will use genetic algorithm to solve it,the sum of the matching degree between the steel pipe as the goal of its minimum value,and finally through the MATLAB simulation using genetic algorithm to obtain the minimum value of the sorting results within the batch,so that the combination of steel pipe sorting within the batch is completed,the field workers can The final experiment shows that this algorithm can meet the enterprise’s requirement of welding steel pipes in the best sorting order. |
