【作者】 高俊；

【导师】 桂鑫；

【作者基本信息】 武汉理工大学 ， 信息与通信工程， 2024， 硕士

【摘要】 飞机结冰是威胁飞机飞行安全的重要因素之一,同时,为了保证复合材料机翼力学性能,需保证机翼除冰期间温度不超过其耐受温度。面向商用飞机对于减重以及节能降耗的要求,要求除冰检测系统能精准进行结冰精准定位及状态检测,同时能实现超温报警。光纤分布式传感技术体积小,抗电磁干扰,易安装,并可进行温度、振动等多物理量的分布式检测,在机翼结冰检测领域具备良好前景。针对机翼结冰检测系统的需要,本文提出一种基于光栅阵列光纤的分布式检测技术,采用相位敏感型光时域反射计(Phase-sensitive Optical Time Domain Reflectometer,φ-OTDR)系统同时进行振动与温度场的检测,一方面,通过振动检测,构建机翼振动频率与其结冰状态之间的映射关系以实现机翼结冰状态检测,另一方面,提出参考传感器结合改进的变步长最小均方误差(Least Mean Square,LMS)自适应滤波算法对相位噪声进行补偿,解决激光器频漂引起相位噪声进而影响温度测量准确性的难题。主要研究内容如下:(1)机翼结冰状态与温度检测模型构建研究。通过振动模态理论构建机翼结冰状态与其振动频率之间的映射关系;基于ABAQUS平台建立机翼结冰前后有限元模型,研究结冰对于机翼振动模态以及振动频率的影响;分析不同光纤分布式传感(Distributed Optical Fiber Sensing,DOFS)系统的传感原理,重点推导基于光栅阵列传感光纤的φ-OTDR系统振动与温度传感数学模型,提出系统对于振动与温度同时检测的可能性。(2)基于相位解调的振动-温度光栅阵列光纤分布式检测系统研究。搭建基于光栅阵列光纤的φ-OTDR系统,并通过实验分析激光器频漂带来的相位噪声;提出基于参考传感器和LMS算法的激光器频漂补偿方法,分析制约LMS算法的因素并进行改进,在MATLAB平台与同类算法进行仿真对比;通过对比传统差分方法与所提出的激光器频漂补偿方法在时域和频域的激光器频漂补偿效果,验证本文激光器补偿方法的优势;通过验证系统对于分布式振动-温度检测的能力。(3)分布式机翼结冰状态与温度检测实验验证。通过搭建的φ-OTDR系统结合激光器频漂补偿方法进行高精度分布式温度测量;分析系统的温度灵敏度、温度分辨率以及多传感器的一致性等关键参数;通过实验室模拟以及冰风洞条件真实环境下对机翼模型的频率检测,验证系统对于机翼结冰状态检测的有效性。更多还原

【Abstract】 Aircraft icing is one of the major threats to flight safety,and in order to ensure the mechanical properties of composite material wings,it is necessary to ensure that the temperature of the wing de-icing system does not exceed its tolerance temperature.Given the commercial aircraft’s requirements for weight reduction and energy conservation,the de-icing monitoring system needs to accurately locate and monitor icing conditions while also achieving over-temperature alarms.Fiber optic distributed sensing technology is small in size,immune to electromagnetic interference,easy to install,and capable of distributed detection of multiple physical quantities such as temperature and vibration,which has good prospects for wing icing monitoring.In response to the needs of the wing icing monitoring system,this thesis proposes a distributed detection technology based on fiber grating array with a phase-sensitive optical time domain reflectometer(φ-OTDR)system to simultaneously detect vibration and temperature fields.On one hand,through the monitoring of vibration field,a mapping relationship between the vibration frequencies of the wing and its icing state is constructed to achieve the monitoring of wing icing state.On the other hand,a reference sensor combined with an improved variable step size least mean square(LMS)adaptive filter is proposed to compensate for phase noise,which solves the problem of phase noise caused by laser frequency drift that affects the accuracy of temperature measurements.The main research contents are as follows:(1)Research on model construction of icing state and temperature detection.A mapping relationship between the icing state of the wing and its vibration frequency is constructed through vibration modal theory.Finite element model models of the wing before and after icing are established based on the ABAQUS platform to investigate the impact of icing on the vibration modes and frequencies of the wing.The sensing principles of different Distributed Optical Fiber Sensing(DOFS)systems is analyzed,with a focus on the derivation of mathematical models for vibration and temperature sensing inφ-OTDR systems based on grating array sensing fibers;The possibility of simultaneous monitoring of vibration and temperature in the system is proposed.(2)Research on vibration-temperature detection system based on phase demodulation and fiber grating array.Aφ-OTDR system based on fiber grating array is established and experiments are carried out to research the phase noise introduced by laser frequency drift.Method for laser frequency drift compensation based on reference sensor and LMS algorithm is proposed.The main factors that limit the performance of traditional LMS adaptive filtering are analyzed,in response to which improvement measures are proposed,and simulation analysis and comparisons with similar algorithms are completed based on the MATLAB platform.By comparing the compensation effects of traditional differential method and the proposed laser frequency drift compensation method in time domain and frequency domain,the advantages of the improved LMS algorithm are verified.The capability of the system for distributed vibration-temperature detection is verified through experiments.(3)Research and experimental verification of distributed aircraft wing icing and temperature monitoring method.The establishedφ-OTDR system combined with an improved LMS algorithm is employed to demonstrate high-precision distributed temperature measurement.Key parameters such as the system’s temperature sensitivity,temperature measurement resolution,and multi-sensor consistency are analyzed.The effectiveness of the system for monitoring the icing state of the wing is verified through frequency monitoring of the wing model in both laboratory simulations and real environment in an ice wind tunnel.更多还原