【作者】 丰志强；

【导师】 阎楚良； 张书明；

【作者基本信息】 中国农业机械化科学研究院 ， 机械设计及理论， 2005， 硕士

【摘要】 飞机机载设备振动/温度环境谱数据处理是飞机机载设备环境可靠性试验的重要组成部分,飞机机载设备在实际使用中将会受到各种使用环境的影响,其中振动环境和温度环境会减少飞机机载设备的使用寿命,影响机载设备的安全性和可靠性,导致飞机机载设备在使用中发生破坏,从而导致难以想象的严重后果。因此飞机机载设备振动/温度环境谱数据处理的真实性对保障飞机机载设备的安全性和可靠性具有十分重要的意义。 本文以JL8飞机为例,首先对飞机进行相关仪器、参数等的改装,由此获得测试所需要的条件,然后进行空测数据采集,最后选取了111个有效飞行起落,作为机载设备振动/温度环境谱数据处理和系统设计的依据。 本文也对试验数据误码的去除做了一定的研究,提出了常见误码信号识别方法、剔除准则以及分析检查。最后对那些分析前存贮为数字时间历程的测量数据,提出了进行数字修正的方法,用以消除某种类型的数据异常。 小波变换(wavelet transform,WT)作为在Fourier变换的基础上发展起来的新型学科,经过十多年的发展,在许多学科得到广泛应用。本文利用小波变换“时-频分析的显微镜”的特性,对利用小波多尺度分解从随机信号中提取周期信号也做了初步的研究。 本文针对飞机机载设备振动/温度环境谱的数据处理主要包括两方面内容:首先进行预处理(原始数据处理),再进行二次数据处理(机载设备环境参数处理)。经过典型状态划分、数据检查、数据检验之后进行原始数据处理。 本文所进行的二次数据处理(机载设备环境参数处理),首先是采用Welch法(改进周期图法)和柯立-杜开法(Cooley-Tukey)计算出飞机各个设备舱在不同的飞行科目、不同的飞行状态下的振动功率谱密度,给出各个设备舱主要典型情况下的功率谱密度图;然后对振动数据进行归纳整理,给出飞机执行不同任务时各个设备舱在不同飞行阶段的振动应力。 本文使用面向对象程序设计语言Visual C++.NET,结合应用软件工程的步骤,实现开发完成了机载设备振动环境谱数据处理和包络系统模块设计,在原有SmartDSP系统基础上,增加集功率谱分析、包络、显示于一体的振动环境谱分析处理系统模块。本系统的设计思想是通过计算机程序实现机载设备振动环境谱数据处理和包络自动化。主要由参数设置、坐标转换、窗函数切换、置信度切换、分位点切换、每帧每段功率谱密度显示、自动输出包络结果等功能模块组成。 本文所进行的飞机机载设备振动/温度环境谱数据处理研究成果,已成功地应用于JL8型教练机和Y7G飞机的机载环境谱数据处理工作之中,取得了一定的经济效益和社会效益。研究成果对机载设备环境谱的数据分析处理技术将会起到一定的推动作用,为今后继续开展机载设备环境谱的数据分析处理工作奠定了基础。更多还原

【Abstract】 The vibration/temperature data processing of environmental spectrum is an important part of environmental reliability test for aircraft airborne equipment. The aircraft airborne equipment constantly works in the various environments. The environment of vibration and temperature can seriously diminish the service life of the aircraft structure. It can affect security and reliability of aircraft airborne equipment. It can lead to many aircraft airborne equipment to be destroyed and many serious results have happened. To sum up, the authenticity of vibration/temperature data processing has great significance for guaranteeing the security and reliability of aircraft airborne equipment.This paper takes JL8 aircraft as an example. At first we must carry on the installation of the electric apparatus and then choose 111 effective flights as the processing data source of the environmental spectrum for aircraft airborne equipment.How to get rid of erroneous data is researched and the distinguishing method of general erroneous data and rejective criterion are pointed out. At last this paper indicates the rectification method for those measurement data before analysis, so we can remove some kind of abnormal data.The wavelet transform as a new-type subject which comes from Fourier transform has been used widely in a lot of subjects and fields after more than ten years of development. This paper makes an elementary research about extraction method for period signal from random signal by wavelet transform. This paper mainly includes two aspects of the environmental spectrum data processing for aircraft airborne equipment. We should carry on the pretreatment (data pre-processing) at first and then carry on the formal data processing (deal with the environmental parameter of airborne equipment). We carry on data pre-processing after typical segment dividing and data checking.Welch method and Cooley-Tukey method are adopted for the formal data processing at first. It calculates the density of power spectrum of vibration for the aircraft at different flight profiles, different flight segments of each equipment cabin. Then the application program we coded provides the chart of power spectrum density for each cabin. At last it envelops vibration data, so it can provide vibration stress of each aircraft equipment cabin during the course of differently flying task.The Object Oriented Program language, i.e. Visual C++ .NET is used in the programming of data processing application. Combining the programming step of the software engineering, this paper has finished the systematic module design of the environmental spectrum data processing. On the base of original SmartDSP system, the aim of this design is the automation of data processing. This system mainly includes the parameter configuration, coordinate transformation, window function, confidence level and quantile switching, etc.The achievement has been successfully applied to the vibration/temperature data processing of environmental spectrum for JL8 and Y7G aircraft airborne equipment. It has achieved great economic benefits and social effect. The achievement will become important driving force for the development of vibration/temperature data processing of environmental spectrum for aircraft airborne equipment. It also has laid a foundation for carrying out vibration/temperature data processing of environmental spectrum for aircraft airborne equipment in the future.更多还原