共查询到19条相似文献,搜索用时 93 毫秒
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本文应用Bootstrap方法对小样本条件下设备故障特征库的构造进行了深入研究。Bootstrap将传统的数理方法和数值模拟技术相结合,去除了利用传统统计工具构造故障特征库时需要占有大量故障样本的要求。以构造气门机构运行状态的故障特征库为例,给出了小样本条件下构造故障特征库的基本方法。应用该方法可以提高设备诊断的效率和准确度,具有较高的工程实用价值。 相似文献
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《内燃机与动力装置》2021,(3)
针对某四缸直列轻型柴油机存在的掉缸故障,采用台架振动测试、道路振动测试、振动疲劳试验以及端子保持力测试等测试手段,系统地分析掉缸故障原因。结果表明:柴油机掉缸原因为喷油器接插件端子保持力可靠性不稳定,在线束拉扯力和振动的相互作用下导致接触件断路。通过改进喷油器接插件结构型式,采用更稳定的接插件端子,优化线束走向,重新设计大刚度的固定支架,优化高压油管管型并增加固定管夹等措施,彻底消除掉缸故障。 相似文献
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《内燃机学报》2016,(3)
气门间隙异常是柴油机常见机械故障之一,对其进行准确的诊断对提高柴油机的使用寿命具有积极的作用.针对柴油机气门间隙异常的问题,在某直列6缸柴油机上模拟了不同气门故障,提出了基于双谱估计、图像处理以及分形理论相结合的故障诊断方法.该方法首先利用双谱估计对非线性、非高斯信号的敏感性质,分析了不同故障状态下振动信号中非高斯成分及二次相位耦合特性,然后通过图像处理技术将双谱图表示为以像素位置及对应颜色强度构成的三维空间曲面,最后利用分形理论提取该曲面的分形盒维数作为故障特征.结果表明:不同状态下柴油机振动信号的双谱及其图像分形维数明显可分,正常状态下的双谱峰值分布最为复杂、分形维数最大,故障状态下的分形维数分别处在不同的范围.因此,以振动信号的分形维数作为特征值可实现柴油机气门故障诊断. 相似文献
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本文应用模糊模式识别技术来诊断汽油机故障,它通过测试汽油机一个工作循环内的转速波动并将它分为和汽油机缸数相等的样本。采用多个参数,确定合适的隶属函数,求出各样本和标准样本的贴近度,最终判别汽油机各缸的工作状态。作者在SY492Q4型汽油机上进行了验证,证明了文中采取的诊断方法的准确性。 相似文献
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《International Journal of Hydrogen Energy》2023,48(50):19262-19278
Data-driven fault diagnosis methods require huge amounts of expensive experimental data. Due to the irreversible damage of severe fault embedding experiments to proton exchange membrane fuel cell (PEMFC) systems, rare available data can be obtained. In view of this issue, a fault diagnosis method based on an auxiliary transfer network (ATN) is proposed. This method uses two parallel neural networks (main and auxiliary neural network) and a prediction fusion module to realize fault diagnosis. The auxiliary neural network is a fault diagnosis classifier pretrained based on both slight and severe fault simulative data, and its weights are transmitted into the ATN structure and frozen. After that, the main neural network is trained based on a large number of slight fault experimental data and a small number of severe fault experimental data. Through ATN, the main neural network learns the abstract features of severe faults under the guidance of auxiliary neural network, and realizes the transfer learning from simulation-based fault diagnosis classifier to experiment-based fault diagnosis classifier. Through testing, the accuracy and precision of ATN-based fault diagnosis classifier with LSTM as both main and auxiliary neural network reaches 0.993 and 1.0 respectively, which is higher than the common data-driven methods. 相似文献
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一种改进的MRVM方法及其在风电机组轴承诊断中的应用 总被引:1,自引:0,他引:1
针对风力机电组轴承故障难以诊断的问题,提出一种基于改进多分类相关向量机(MRVM)的风力机电组主轴轴承概率性智能故障诊断方法。首先,为了减少人为设定核参数的主观性以提高其分类性能,提出MRVM最优核参数自适应选取方法;然后,通过仿真实验结果验证所提方法的有效性及优越性;最后,以风电机组主轴滚动轴承故障诊断为实例,提取小波包能量为故障特征输入到改进后的MRVM中进行故障识别。实验结果表明,该方法可提高故障诊断准确率及效率,同时可输出故障诊断结果的概率信息,为实际检修人员提供更多参考信息。此外,通过与其他方法的对比实验进一步表明该方法在智能故障诊断方面的优越性。 相似文献
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《International Journal of Hydrogen Energy》2021,46(60):30828-30840
The reliability of fuel cell tram depends largely on the normal operation of on-board proton exchange membrane fuel cell (PEMFC) system. Therefore, timely and accurate fault diagnosis is necessary to further commercialize the fuel cell tram. And, a new fault diagnosis method BPNN-InceptionNet based on information fusion and deep learning is proposed in this paper. In this method, high-dimensional abstract features are extracted from the original measurement information by back propagation neural network (BPNN) and converted into feature maps for information fusion in feature level. Then the feature maps are transferred to a proposed Convolutional Neural Network (CNN) based on InceptionNet to realize fault classification. From the experiments, it is found that the kappa coefficient by BPNN-InceptionNet for the test set can reach 0.9884, which is better than that by BPNN, BPNN-VGG, and support vector machine (SVM) classifiers, meaning that the proposed method can achieve better diagnostic performance. 相似文献
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Control of a doubly fed induction generator in a wind turbine during grid fault ride-through 总被引:5,自引:0,他引:5
This paper analyzes the ability of a doubly fed induction generator (DFIG) in a wind turbine to ride through a grid fault and the limitations to its performance. The fundamental difficulty for the DFIG in ride-through is the electromotive force (EMF) induced in the machine rotor during the fault, which depends on the dc and negative sequence components in the stator-flux linkage and the rotor speed. The investigation develops a control method to increase the probability of successful grid fault ride-through, given the current and voltage capabilities of the rotor-side converter. A time-domain computer simulation model is developed and laboratory experiments are conducted to verify the model and a control method is proposed. Case studies are then performed on a representatively sized system to define the feasibility regions of successful ride-through for different types of grid faults. 相似文献