【作者】 吴晓；

【导师】 靳世久；

【作者基本信息】 天津大学 ， 精密仪器及机械， 2010， 博士

【摘要】 管道运输已经成为与公路、铁路、航空和水运等并驾齐驱的五大运输行业之一,在国民经济和国防建设方面发挥着越来越大的作用。但随着管龄增长以及施工缺陷、人工破坏和腐蚀等原因,管道泄漏事故频频发生,不仅造成重大的经济损失,还严重污染环境。管道在线内检测器(Smart Pig)是管道腐蚀检测最广泛的方法。地面标记系统是整个管道内检测系统的管外定位部分,是消除检测器里程累积误差、精确定位管壁缺陷的关键设备。它可以将管道缺陷定位误差减少到几米甚至一米以内,为管道维修提供准确科学的数据,避免了盲目开挖。内检测器跟踪技术是内检测器在管道中出现意外被卡住之后,确定管道内检测器在管道内位置的技术。由于管道金属介质的屏蔽作用,一般的电磁波技术在应用于地面标记跟踪时受到了很大的限制。而传统的基于磁通量的地面标记技术穿透的距离有限,已经不能满足现在管道越埋越深,管壁越来越厚所带来的新的需求。本文提出了一种新的基于声传感器阵列的地面标记跟踪技术。通过声传感器阵列测量内检测器与管壁的摩擦和碰撞声音来进行标记。提出了基于内检测器自发声的跟踪技术,对被卡住的内检测器在管道中的位置进行定位。本文主要进行了以下几方面的研究工作:1、提出了利用内检测器与管壁的摩擦声和焊缝冲击声进行标记的方法。焊缝冲击声在土壤中传播距离较远,这样地面标记器能够标记埋地更深的管道。2、提出了在小波域内进行独立分量分析的声音信号增强方法,在位置未知的情况下,能够对强环境噪声下内检测器发出的声音信号进行增强。3、提出了基于声源方位角的内检测器信号判定方法。使用基于小波包熵的信号特征提取方法、基于经验模态分解的信号特征提取方法和AR模型参数法对采集到的声音信号进行特征提取,使用基于支持向量机的人工神经网络方法对信号进行模式识别。4、使用了基于信号到达时间差(TDOA)的定位方法对内检测器进行定位。提出了利用小波分解和EMD分解的方法来提高时延估计的精度。5、提出了基于内检测器自发声的跟踪技术。设计了内检测器自发声装置发出特定频率的声音信号,利用声传感器阵列检测该声音信号相位差来对内检测器定位。并通过实验验证了理论的可行性。6、通过实地试验来验证了本文所提方法的有效性。设计了基于声阵列的地面标记器硬件系统结构,为系统实用化做了铺垫。更多还原

【Abstract】 Pipeline transportation has become one of the five chief transporting industries while the other four are highway carriage, railage, air-ferry and water carriage,and is playing a more and more important part in national economy and national defence. However, along with the age of pipe growth and construction blemish, the artificial reasons such as breakage and corrosion etc., pipeline leakage accident often takes place. The leakage accidents not only result in huge economy loss, but also serious environment pollution. The Pipeline Internal Detector (Smart Pig) is the most widely used equipment in detecting pipe corrosion.The above ground marker system (AGM), which is designed to locate the corrosion precisely by eliminating the cumulate error of distance the PIG passing through and avoid blindness digging, plays a pivotal role among the whole system. The tracking technology of inner inspector is used to locate the inspector in pipe from ground, when the inspector was locked in pipe.Because the shield functions of metal media of pipe, the general electromagnetic wave can hardly penetrate the pipe wall. On the other hand, the penetrable distance of traditional magnetic flux AGM was limited, and can’t satisfy the new require of more deep and thicker pipeline wall.A new kind of above ground benchmarking and tracking technology of pipeline internal inspection instrument based on geophone array was proposed in this dissertation. The benchmarking was carried on by the geophone array detecting low energy voice on the pipewall. The voice was generated when the cups or discs of a pig encounter internal weld beads between the pipes and fittings ,or when the pig rubbed against the pipe wall surface. When pipeline internal inspection instrument was locked in pipeline, it was tracked by the geophone array to locate the voice which was sent by inspector.The dissertation mainly covers the following aspects:1. A above ground benchmarking technology based on geophone array according to crash voice of inspector and the weld seams of pipe was proposed. The above ground marker could benchmark deeper pipe because the crash voice could spread more distance in soil.2. A voice signal enhancement method of an independent component analyze in the wavelet domain was proposed , which in case of an unknown location information, was able to enhance the voice of internal detector in noise case environment.3. A sound signal determinant method based on the internal sound source azimuth detector was proposed. Wavelet packet entropy, empirical mode decomposition and the AR model parameters was used in the signals feature extraction method, and the artificial neural network based on support vector machine was used to identify the sound signals.4. The time difference of arrival based on signals (TDOA) location method was used. In order to improve the accuracy of delay estimation, the wavelet decomposition and the EMD method was proposed.5. An internal detector tracking method based on measurement of phase difference of fixed-frequency sound signal waveform was proposed, which was verified through experiments.6. The on-the-spot experiment was carried on to vertify the proposed theory. The hardware system architecture of above ground marker was designed, which was prepared for the practical usage.更多还原