This paper examines the effectiveness of neural network algorithms for hydraulic system fault detection and a novel neural network architecture is suggested. The proposed gated convolutional autoencoder was trained on a simulated training set augmented with just 0.2% data from the real test bench, dramatically reducing the time needed to spend with the actual hardware to build a high-quality fault detection model. Our fault detection model was validated on a test bench and showed accuracy of more than 99% of correctly recognized hydraulic system states with a 10-s sampling window. This model can be also leveraged to examine the decision boundaries of the classifier in the two-dimensional embedding space.

The problem of automatic reliability monitoring and reliability-centered maintenance is increasingly important today. In this paper, we compare the accuracy of four machine learning approaches for fault detection in a hydraulic system. The first three approaches are based on SVM classifiers with linear, polynomial and RBF kernels and the last one is a gradient boosting on oblivious decision trees. We evaluate algorithms on the synthetic dataset generated by our simulation model of the helicopter hydraulic system and show that high accuracy fault detection can be achieved.

The article deals with diagnostics of hydraulic systems using phase portraits. A brief review of the existing methods for diagnosing hydraulic units identifying their advantages and disadvantages is given. An approach based on the analysis of dynamic characteristics of a hydraulic system and phase portraits of hydro-mechanical units in their operational and faulty conditions is proposed. As an example, we consider a dynamic model of a simplified hydraulic system consisting of standard components. By adjusting the model parameters characteristic faults typically occurring in operation, such as internal leaks in the pump, contamination of the hydraulic fluid with mechanical impurities, sticking of the valve, etc. were artificially introduced in hydro-mechanical units. A family of phase portraits of a hydraulic system for the operational condition and various faulty ones was constructed. A quantitative estimate of their changes, based on calculating the difference in the areas of the figures restricted by their graphs, is proposed. As a result, it was established that failures and malfunctions introduce changes in the phase portraits of hydro-mechanical units, which makes it possible to apply the proposed approach as a basis for diagnosing the technical condition of hydraulic systems.

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In order to increase efficiency of diagnostics of electro-hydro-mechanical systems (EHMS) it is advisable to have simulation models of typical faults. Such approach makes it possible to estimate in advance, even at the stage of mathematical modeling, the impact of different faults on functioning of hydraulic systems. This work is aimed at creating a database containing complexes of diagnostic features, which allow distinguishing types of faults, their causes and stages of development. In the paper, typical faults of EHMS are presented on the basis of statistical information from literature sources and experimental research. They include internal and external leakages, spool and sleeve sticking, degradation of power fluid. The causes of faults and their impact on hydraulic systems functioning are considered. Simulation models of typical faults are implemented and studied in the SimulationX software package. The static and dynamic characteristics of the systems are investigated in order to identify diagnostic signs of various faults. The impact of typical faults on various system parameters is discussed. During the research, the tasks of selecting the rational location of sensors of different types (pressure, flow, displacement, or force sensors), their quantity for recognition of a typical fault are solved. The results of theoretical and experimental studies of serviceable and faulty systems for cases of control and disturbance actions are presented. Comparative analysis of transient processes of serviceable and faulty EHMS is presented with assessment of difference between theoretical and experimental data. The results of the work allow to more rationally designing the diagnostic complex for more accurate identification of the type of fault, stage of its development and prediction of residual service life of EHMS.

Статья посвящена изучению процесса заедания золотниковых пар авиационных гидроприводов под действием частичек загрязнения, содержащихся в рабочих жидкостях гидравлических систем воздушных судов. Рассмотрен механизм воздействия этих частичек на гидропривод. Детально проанализирован процесс развития заедания. По результатам анализа разработаны две методики, позволяющие оценить состояние золотниковой пары, а также спрогнозировать появление отказа. Первая из них основана на непосредственном замере величины зазора в золотниковой паре гидропривода в процессе ремонта. Для её реализации необходимо аналитическим путём определить величину минимально допустимого зазора, обеспечивающего устойчивую работу агрегата во всём диапазоне давлений в гидравлической системе. Вторая методика является менее трудоёмкой (но и менее точной) по сравнению с первой и основывается на измерении значения макропараметра гидропривода, изменение которого связано с изменением величины зазора в золотниковой паре в процессе эксплуатации. Предварительно необходимо определить зависимость выбранного макропараметра от величины зазора в золотниковой паре. Реализация описанных методик позволит существенно повысить экономический эффект от использования воздушных судов путём сокращения расходов и времени их простоя во время ремонта.Гидравлическая система, рабочая жидкость, частички загрязнения, гидравлический привод, заедание золотниковых пар, зазор, оценка и прогнозирование технического состояния.

Рассматриваются основные закономерности, отражающие особенности и условия эрозионных процессов как следствие хозяйственной деятельности на речных водосборах, ее роль в развитии рельефа и влияние на состояние природно-хозяйственных систем на Южном Урале и Предуралье. Одним из основных факторов, обуславливающих активизацию эрозионных процессов, является трансформация склонового стока, в т.ч. увеличение его поверхностной составляющей и разрушающей способности водных потоков в условиях деградации природных комплексов на водосборе. Показано, что интенсивное развитие и тенденции к их увеличению сохраняются в регионах (например, в Республиках Башкортостан и Татарстан) благодаря усилению пастбищной нагрузки из-за увеличения поголовья скота в частном секторе и исчезновения экономических стимулов защиты от эрозии пахотных земель, несмотря на общее снижение антропогенных нагрузок. Дается характеристика негативного влияния указанных процессов на хозяйственно-экономические и экологические условия в бассейнах малых рек.

А method based on comparing oscilloscope patterns of operational parameters with reference curves is one of the most promising methods of diagnosing hydraulic systems among the existing ones. Its implementation does not allow accurate localization of the faulty unit in the system and quantitative estimation of the magnitude of the fault. To eliminate these shortcomings, it is advisable to use simulation models of hydraulic units, taking into account typical faults of a hydraulic system. Their use makes it possible to evaluate the effect of a particular malfunction on the change of dynamic parameters at the stage of mathematical modeling. As a result of the analysis of statistical information and literary sources, characteristic faults of hydraulic systems are identified. Their causes and the impact on the operation of hydraulic units are examined. Simulation models of units taking into account typical faults are described in the Matlab / Simscape software package. They are implemented using a typical hydraulic system as an example. Dynamic characteristics of a hydraulic system in a healthy condition and those of a system with one of the characteristic faults are compared.