Study On Ultrasonic Location Of Gas Leakage Point Based On TDOA And ED Data Fusion

In recent years,ultrasonic leakage detection and location technology has been widely used and paid attention in various fields,and it achieves the purpose of leakage detection and positioning according to the analysis of ultrasonic that injection of high pressure gas from leak hole of seal container or pipeline generates.The ultrasonic leakage detection and positioning system has a good application prospect because of its high precision,high realtime and so on.At present,scholars at home and abroad are already mature in the technology research and system realization of ultrasonic leakage detection.The purpose of this paper is to propose a method of ultrasonic leakage location and the design an accurate leakage location system.On the basis of the linear array and circular array of ultrasonic sensors that have been studied by scholars,this paper presents an array form of planar four element array and the purpose is to locate the leakage points in the three-dimensional space and to detect the measured containers or pipes of arbitrary shape.Introduction of sensor area array greatly widens the application scope of ultrasonic leakage detection and positioning system.The simple structure of planar four element array reduces the cost of detection system and provides the precondition for large-scale application of the leakage detection and positioning system.Secondly,the principle of the commonly used time difference location algorithm and energy attenuation location algorithm is analyzed in this paper.In this study,the arrival time difference is divided into two parts: several signal cycles and residual time difference.This paper proposes the method of using the envelope of ultrasonic signal to get the number of cycles,thus gets rid of the limitation that arrival time difference can not exceed the signal period.The limitations of the two location methods are analyzed,then feature layer data fusion algorithm based on the extended Kalman filtering method is proposed in this paper.It connects eigenvectors of the time difference location method and the energy attenuation location method,and calculates the location of leakage point.The simulation shows that the data fusion algorithm can make the location of leakage point approach the real value continuously through iterative calculation.Finally,an ultrasonic leak detection and location system in the form of sensor array is designed,and an experimental device to verify the proposed planar four element array and leak location algorithm based on data fusion is built.The experiment compares the practicability and accuracy of TDOA algorithm,ED algorithm and location algorithm based on data fusion proposed in this paper.The experimental results show that TDOA algorithm is very difficult to get the leak location because of the divergence problem,the error of computing results of the location algorithm based on data fusion is less than 20 mm and its precision is about 10 times higher than the ED algorithm.The experiment verifies the feasibility and effectiveness of the planar four element array and ultrasonic leakage localization algorithm based on data fusion.