Research On Precision Control Technologies For Detection System Of Defects Inside Small Pipes

With the rapid development of manufacturing,detection technology of defects inside small pipes is becoming more and more important in the field of industrial manufacturing and quality control.However,the conventional detection method for pipeline is not suitable for detecting small pipes with diameter of about 10 mm or less,and for the current several useful detection methods for small pipes,such as industrial endoscope and in-pipe micro robots,there are still some deficiencies and application limitations and they cannot meet the needs of industrial large-scale automation testing.With the combination of the visual inspection technology and industrial robot technology,this paper researches a detection system for defects inside small pipes to realize automatic,fast,high accuracy,non-contact detecting.Based on previous laboratory studies,this paper focuses on the improvement of measurement system and puts forward suitable precision control schemes to solve the problem of misalignment between sight-pipe's axis and pipe's axis and improve measuring accuracy of the system.Finally,experiments were conducted to verify the precision control scheme.The main work accomplished in this paper includes the following:1.After understanding the importance of internal defects detection technology for small pipes and conventional pipeline detection technology solutions,analyze the shortage and application limitations of the current detection method,and determine the content of this paper.2.Introduce the main composition and working principle of small pipes detection system,analyze and compare the fixed and flexible detection system,and point out the current problem of the measuring system.3.The misalignment of the sight-pipe and the pipe to be detected has decisive influence on the accuracy of measuring system.Analyze the shortage of the scheme for the fixed and flexible detection system to realize the alignment of sight-pipe and pipe through equipment attitude adjustment,and propose a new scheme through image distortion correction to realize precision control indirectly.4.Research the distortion correction method of the unfolded image of small pipes internal surface.Analyze the cause of the longitudinal image distortion and Lateral image distortion on the unfolded image,establish proper mathematical model,and put forward an image distortion correction scheme for the detection system for defects inside small pipes.5.Analyze the error of the measuring system and test the precision control scheme proposed in this paper by experiments.