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音频管理组件是民航飞机话音通信系统的传输中枢,交联复杂,测试项目繁多,且主要机型的相关组件标准各异,造成目前该类组件的测试效率低下,人为差错率高,测试成本高昂;通过对各机型相关组件自动测试需求的分析,建立测试模型,整合测试资源,完成了基于PXI总线的多机型音频管理组件综合测试系统的设计;测试系统采用模块化结构,结合自主设计的多种测试仿真组件,通过统一的测试执行管理平台控制测试资源完成自动测试;实践证明,该系统工作稳定,完全满足多种机载音频管理组件的测试需求,并显著提高了的测试的效率和准确率。 相似文献
83.
TCAS是保障飞机飞行安全的重要机载电子设备,然而国内对TCAS系统板卡只能进行板卡级的测试,不能进行元件级的维修和测试。以TCAS系统中的视频存储器板为例,根据板卡电路特点及适航要求提出一种改进后的基于故障树分析的元件级故障诊断新方法,该方法通过对待测板卡提供外围激励信号、编写程控控制命令、故障树分析和编写输出结果优化程序等对待测板卡进行故障检测与定位,该系统通过调试与运行证明效果良好,并由实验数据得出故障检测精度大大提高,为国内自主研发元件级自动检测设备和机载电子板卡的深度维修提供了可靠的理论依据。 相似文献
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工况的变化会引起功率变换器电路健康表征参数随之变化,导致无法判断健康表征参数是因电路性能的退化还是因工况的变化引起的。针对该关键问题,以航空逆变器为研究对象,首先采用多评价指标优选模型优选出相关敏感的健康表征参数;然后基于极限学习机建立工况-无故障情况下健康表征参数映射模型;最后基于当前健康表征参数与映射模型输出的健康表征参数之间的相对变化量构建考虑工况条件的电路健康指标,实现不同工况下航空逆变器的健康评估。实验结果表明,该评估方法可以有效减小工况变化对健康指标的影响。在变工况情况下,相比于直接基于欧氏距离构建健康指标的评估方法,平均绝对误差(Mean Absolute Error,MAE)和均方根误差(Root-Mean-Square Error,RMSE)分别降低了64.4%、66.8%。 相似文献
88.
《Expert systems with applications》2007,32(1):157-171
This paper presents a new type-2 fuzzy logic system model for desulphurization process of a real steel industry in Canada. The type-2 fuzzy logic system permits us to model rule uncertainties where every membership value of an element has a second order membership value of its own. In this paper, we propose an indirect method to create second order membership grades that are amplitudes of type-2 secondary membership functions, where the primary memberships are extracted by implementation of fuzzy clustering approach. In this research, Gaussian Mixture Model (GMM) is used for the creation of second order membership grades. Furthermore, a reduction scheme is implemented which results in type-1 membership grades. In turn, this leads to a reduction of the complexity of the system. Two methods are used for the estimation of the membership functions: indirect and direct methods. In the indirect method, the system uses an interpolation scheme for the estimation of the most appropriate membership functions. In the direct method, the system is tuned by an inference algorithm for the optimization of the main parametric system. In this case, the parameters are: Schweizer and Sklar t-norm and s-norm, combination of FATI and FITA inference approaches, and Yager defuzzification. Finally, the system model is applied to the desulphurization process of a real steel industry in Canada. It is shown that the proposed type-2 fuzzy logic system is superior in comparison to multiple regression and type-1 fuzzy logic systems in terms of robustness, and error reduction. 相似文献
89.
《Composites Part A》2001,32(9):1237-1242
This paper describes an investigation of in-plane elastic properties of impact damaged regions in composite laminates. Quasi-isotropic carbon fibre/epoxy laminates were impacted and the impact damage examined by ultrasonic C-scanning, optical microscopy and thermal deplying. After impact damage observations, specimens were cut from the laminates and tested in tension and compression. The elastic modulus of the impact damage was, in both tension and compression, mainly controlled by the amount of fibre breakage. Interestingly, layers with broken fibres could sustain some load in compression, which led to higher elastic modulus in compression than in tension. The effect of delaminations on the elastic modulus was quite small in both tension and compression. The through-the-thickness variation of in-plane stiffness was studied by successively removing plies. The variation in stiffness was negligible, probably as a result of the very uniform distribution of delaminations and fibre breakage through the thickness of the laminates. 相似文献
90.
One of the important factors in the structural health monitoring systems is the amount of data that need to be analysed in real time. This study investigated the use of artificially deteriorated signals of Lamb waves in training the novelty detection (ND) system for the early damage detection. In this system Auto-associative Neural Networks were trained using principal components calculated on the basis of experimentally measured signals. The specimens studied relate to two different materials commonly used in the aerospace industry, i.e. aluminium and glass fibre reinforced polymer. Lamb waves measured in these specimens are a good example that the ND algorithm works correctly in case of simple as well as complex signals. Furthermore, it was found that the designed ND system remained sensitive and robust even when it used raw signals with a relatively low sampling rate, on a fairly narrow time window and even noised signals. 相似文献