【作者】 刘晓琳；

【导师】 李志全；

【作者基本信息】 燕山大学 ， 控制科学与工程， 2013， 博士

【摘要】 随着我国民航运输事业发展的需要，现代飞机装备逐渐向大规模、复杂化发展。导线是飞机电气系统的重要装置，连接于各种用电设备之间，承担了传递动力电源的任务，其性能好坏是影响用电设备稳定工作和飞机安全飞行的重要因素。硬性故障(短路故障和断路故障)和软性故障(磨损故障)是飞机导线的典型故障，会导致信号传输不正常、指示仪表不稳定、操控机械不工作、引发飞机火灾等后果。因此，为了保证飞机的安全性和持续适航性，导线故障诊断与定位是提高民航机务维修质量和效率的一项重要内容。开展本课题的研究，对于跟踪国际民航研究热点、提高我国民航科研水平具有促进作用。论文在目前国内外应用反射测量原理的飞机导线故障诊断与定位技术研究现状的基础上，首先研究了飞机导线的物质特性和电气特性，给出了导线物质结构的变化对信号在导线中传播过程的影响规律，研究了信号的传播速度与其频率特性、导线的结构特性、材料特性和温度特性之间的关系，给出了确定信号传播速度的依据。然后，以飞机导线的短路故障和断路故障为研究对象，目的在于寻求一种控制方法能够尽可能地提高应用时域反射测量原理进行故障诊断与定位的精度。采用了小波包变换算法对故障点的时域反射信号进行降噪处理，抑制了故障测试系统受到电磁信号干扰的影响。采用了基于偏最小二乘回归分析算法和互相关算法的故障定位方法，确定了入射信号与反射信号的时间间隔，实现了导线硬性故障的精确定位。其次，针对飞机导线磨损故障反射信号微弱，不易采用时域反射测量原理诊断与定位的问题，提出了应用时域-频域联合反射测量原理的飞机导线磨损故障诊断与定位方法。该方法通过发射一个线性调频信号和高斯包络组成的包含时域和频域信息的入射信号，得到故障点的反射信号。再采用分数阶小波包变换算法对时域-频域反射信号进行噪声抑制，通过设计入射信号与反射信号的互相关函数，解决了导线软性故障的定位问题。最后，通过设计以工控机为控制核心、以LabVIEW为驱动软件的飞机导线硬性故障和软性故障诊断与定位功能于一体的测试系统，实现了入射信号参数发射、导线数据信息提取、反射信号降噪处理和故障诊断与定位整个过程的自动完成。实验结果验证了所提出的方法在飞机导线的硬性故障和软性故障诊断与定位方面的有效性和准确性。更多还原

【Abstract】 With the development of Chinese civil aviation transport service, the modern aircraftequipment has gradually improved to be large-scale and complicated. The wire is animportant device of the aircraft electrical system, which connects the various electricalequipments together and transfers the electrical signals. That its performance is good orbad directly influences the stability of the electrical equipment and the security of theaircraft flight. The short circuit fault, the open circuit fault and the wear fault are thetypical faults of the aircraft wire and will cause that the signal transmission to beabnormal, the indicating instrument to be instable, the mechanical control to be inactiveand the aircraft to be ignitable. Therefore, in order to ensure the safety and continuousairworthiness of the aircraft, the wire fault diagnosis and localization is an importantcontent to improve the quality and efficiency of the civil aviation maintenance repair. Thefunction of this research task is to track the research topics of the international civilaviation and improve the scientific research level of Chinese civil aviation administration.In this paper, in the first place, the material and electrical properties of the wire arestudied based on the thorough research of the reflection technique of the fault diagnosisand localization of the aircraft wire. The rule of the signal in the wire influenced by thevariation of the material structure is put forward. And the relationships between thefrequency of the signal, the structure characteristics of the wire, the material properties ofthe wire, the circumstance temperature and the propagation velocity of the signal arestudied separately. The propagation velocity of the signal is determined.In the second place, in order to improve the accuracy received by the short circuitfault and the open circuit fault diagnosis and localization of the aircraft wire based on thetime domain reflection measurement principle, a control method is proposed. The waveletpacket transform algorithm is used to denoise the reflected signal in order to suppress theelectromagnetic interference of the measuring environment. By making use of themethods of the partial least-squares regression analysis algorithm and thecross-correlation algorithm respectively, the time interval of the incident signal and the reflected signal is identified and the accurate position of the wire hard fault is obtained.In the third place, due to the reflected signal of the wear fault of the aircraft wire istoo weak to detect using the time domain reflection measurement principle, so thetime-frequency combined domain reflection measurement method is proposed todiagnose and locate the wear fault. By emitting an incident signal in the time-frequencycombined domain which is composed of a linear frequency modulation signal and agaussian envelope, the reflected signal of the wear fault is obtained. The fractionalwavelet packet transform algorithm is used to denoise the reflected signal. Then thecross-correlation function of the incident signal and the reflected signal is designed tolocate the soft fault of the aircraft wire.In the last place, the wire fault diagnosis and localization system is designed, ofwhich the industrial control computer is the control core and the LabVIEW is the driversoftware. The whole process of transmitting the incident signal, searching the wire data,denoising the reflected signal, diagnosing and locating the fault is accomplishautomatically. The experiment results show that the proposed methods to diagnose andlocate the hard fault and the soft fault of the aircraft wire are effective and accurate.更多还原