| Belt conveyor is an important way of transport for bulk materials,with the advantages of low cost,long distance and large transport capacity.Conveyor belt is an important part of a belt conveyor.Due to the occasional sharp impurities in bulk materials,such as gangue and anchor rods in coal,they may penetrate the conveyor belt when they fall onto the surface of the conveyor belt which will make the conveyor belt longitudinal tear.Conveyor belt longitudinal tear can cause factories into downtime,resulting in economic losses,serious may also cause a fire and have serious consequences.Therefore,the conveyor belt longitudinal tear real-time detection is a problem need to be solved.Conveyor belt longitudinal tear mainly include two kinds of detection methods of contacting and non-contacting.The contacting detection methods are mostly have the problem of low sensitivity.For the non-contact detection method,visual inspection is a popular research direction in recent years.In order to realize the real-time,reliable detection and control the conveyor belt stopping when longitudinal tear detected,the longitudinal tear detection and positioning method based on the visible light CCD is studied in depth,and the conveyor belt longitudinal tear monitoring system is designed in this paper.The main contents of this paper are as follows:According to the research status of the conveyor belt longitudinal tear of domestic and overseas in recent years,the principle of longitudinal tear target detection based on visible CCD camera and laser light line source is proposed.The method of image preprocessing,corner detection algorithm,straight line detection algorithm and circle detection algorithm are studied.According to the FAST corner detection algorithm,the Progressive Probabilistic Hough Transform(PPHT)straight line detection algorithm and the 2-1 Hough Transform(21HT)circle detection algorithm,the principle and method of longitudinal tear detection and positioning based on image feature extraction are designed.Based on the principle of longitudinal tear detection and the principle of positioning,a miniaturized longitudinal tear detection wireless sensor node is designed to realize the detection and positioning function of longitudinal tear.The node uses the NVIDIA Jetson TK1 embedded GPU platform for image processing.The node detection software implements the principles and methods of longitudinal tear detection and positioning,and implemented by C++ programming language,and based on OpenCV visual library to ensure the processing speed,and use Qt to design a user interface for debugging.The node uses a wireless network,it can connect to the underground fiber ring network through the wireless network,to achieve the detection data to the host computer database real-time uploading.The database using MongoDB database,for saving historical data.According to the designed longitudinal tear detection wireless sensor nodes,a longitudinal tear detection system is built.The speed sensor,the longitudinal tear detection wireless sensor node and the host computer are connected together to realize the function of image acquisition,processing,result analyzing and positioning and data uploading.The experimental platform is built to test the performance of real-time and accuracy of the detection system.The test results show that the proposed method has good real-time and accuracy performance,and meets the requirement of longitudinal tear detection of conveyor belt.In order to control the conveyor belt stopping when longitudinal tear detected,the control project experimental platform is designed.The platform uses Siemens S7-300 PLC,and through the PLC programs to control the frequency converter to achieve speed control function and the motor start and stop function.The host computer and PLC communicate through the OPC server.The OPC client software is programmed by C# and connect to the detection system,for controlling the conveyor belt stopping when longitudinal tear detected.The monitoring system proposed in this paper realized the miniaturization and networked of the mine conveyor belt longitudinal tear detection sensor nodes,as well as the real-time detection and the defect location of the conveyor belt longitudinal tear,and the transmission of the data through network.The system achieved the automation of the detection of conveyor belt longitudinal tear and the control of motor stopping.It has important significance on improving the safety of mining conveyor belt running. |
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