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Bearing Fault Diagnosis Method of Wind Turbine Based on Improved Anti-Noise Residual Shrinkage Network

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Energy Engineering 2022年第2期119卷 665-680页

作者： xiaolei li Beijing Goldwind Science&Goldwind Huineng Technology Co. Ltd.Beijing100176China

Aiming at the difficulty of rolling bearing fault diagnosis of wind turbine under noise environment,a new bearing fault identification method based on the Improved Anti-noise Residual Shrinkage Network(IADRSN)is ***,the vibration signals of wind turbine rolling bearings were preprocessed to obtain data samples divided into training and test ***,a bearing fault diagnosis model based on the improved anti-noise residual shrinkage network was *** improve the ability of fault feature extraction of the model,the convolution layer in the deep residual shrinkage network was replaced with a Dense-Net *** further improve the anti-noise ability of the model,the first layer of the model was set as the Drop-block ***,the labeled data samples were used for training model and the trained model was applied to the test set to output the fault diagnosis *** results showed that the proposed method could achieve the fault diagnosis of wind turbine bearing more accurately in the high noise environment through comparison and verification.

关键词： Bearing fault diagnosis improved residual shrinkage network noise immunity

Numerical exploration on the thermal invasion characteristics of two typical gap-cavity structures subjected to hypersonic airflow

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Chinese Journal of Aeronautics 2020年第6期33卷 1589-1601页

作者： Zhenhuan li Xinlin XIA xiaolei li Chuang SUN Key Laboratory of Aerospace Thermophysics of Ministry of Industry and Information Technology School of Energy Science and EngineeringHarbin Institute of TechnologyHarbin 150001China

In this paper,numerical investigation of hypersonic gas flow over two typical gap-cavity structures is carried out using all-speed preconditioned density-based *** structures filled with porous seal in the gap are often present at the joint locations of control surfaces of the hypersonic ***-domain approach is adopted to integrate the governing equations for both porous and fluid *** basic thermal invasion characteristic is first illustrated using the maze gap-cavity structure without ***,the influence of seal filling depth on the thermal invasion characteristic is investigated for the structure with ***,a comparison of thermal invasion characteristics between maze and straight gap-cavity structures is performed to examine the influence of gap *** show that the main source of hot airflow invading into the gap is from the millimeter scale gas layer within the boundary *** the invasion characteristic presents approximate stationary behavior.A primary vortex occurs in the gap adjacent to the leeward wall,which is ascribed to the impinging effect between the separate boundary flow and the windward *** effect is also the main driving force of thermal invasion.A treatment of filling the seal in certain depth inside the gap can significantly reduce the thermal load of seal and maintain an acceptable level of the invading mass flow ***,it is found that the gap bending exerts a limited block effect on the thermal invasion without sealing,and this effect can be ignored with *** results can provide a reference for optimizing the seal gap-cavity structure configuration.

关键词： Gap-cavity structure Heat transfer Hypersonic flow Porous material Thermal invasion

Output Consensus for Heterogeneous Nonlinear Multi-Agent Systems Based on T-S Fuzzy Model

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Journal of Systems Science & Complexity 2017年第5期30卷 1042-1060页

作者： li xiaolei LUO Xiaoyuan li Shaobao GUAN Xinping School of Electrical Engineering Yanshan University Polytechnic School of Engineering New York University Institute of Electronic Information and Electrical EngineeringShanghai Jiao Tong University

In this paper, the output consensus problem of general heterogeneous nonlinear multi-agent systems subject to different disturbances is considered. A kind of Takagi-Sukeno fuzzy modeling method is used to describe the nonlinear agents' dynamics. Based on the model, a distributed fuzzy observer and controller are designed based on parallel distributed compensation scheme and internal reference models such that the heterogeneous nonlinear multi-agent systems can achieve output consensus. Then a necessary and sufficient condition is presented for the output consensus problem. And it is shown that the consensus trajectory of the global fuzzy model is determined by the network topology and the initial states of the internal reference models. Finally, some simulations are given to illustrate and verify the effectiveness of the proposed scheme.

关键词： Heterogeneous nonlinear multi-agent system internal reference model output consensus T-S fuzzy model.

Consensus of second-order nonlinear multi-agent systems via sliding mode observer and controller

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Journal of Systems Engineering and Electronics 2017年第4期28卷 756-765页

作者： xiaolei li Xiaoyuan Luo Shaobao li Jianjin li Xinping Guan School of Electrical Engineering Yanshan University Tandon School of Engineering New York University Institute of Electronic Information and Electrical Engineering Shanghai Jiao Tong University

This paper investigates the consensus problem of second-order nonlinear multi-agent systems (MASs) via the sliding mode control (SMC) approach. The velocity of each agent is assumed to be unmeasurable. A second-order sliding mode observer is designed to estimate the velocity. Then a distributed discontinuous control law based on first-order SMC is presented to solve the consensus problem. Moreover, to overcome the chatting problem, two controllers based on the boundary layer method and the super-twisting algorithm respectively are presented. It is shown that the MASs will achieve consensus under some given conditions. Some examples are provided to demonstrate the effectiveness of the proposed control laws.

关键词： nonlinear multi-agent system sliding mode observer consensus sliding mode controller

Removal of SO2 using ammonium bicarbonate aqueous solution as absorbent in a bubble column reactor

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Frontiers of Chemical Science and Engineering 2013年第2期7卷 185-191页

作者： xiaolei li Chunying ZHU Youguang MA School of Chemical Engineering and Technology State Key Laboratory of Chemical Engineering Tianjin University Tianjin 300072 China

In this work, the removal of SO2 from gas mixture with air and SO2 by ammonium bicarbonate aqueous solution as absorbent was investigated experi- mentally in a bubble column reactor. The effects of the concentration of ammonium bicarbonate, the SO2 inlet concentration of gas phase and the gas flow rate on the removal rate of SO2 were studied. The results showed that the higher the SO2 inlet concentration and the gas flow rate, the shorter the lasting time of SO2 completely removed in gas outlet, and then the faster the decrease in the removal rate of SO2. The lasting time of SO2 completely removed in gas outlet increased with increasing ammonium bicarbonate concentration. During the process of SO2 absorption, there was a critical pH of solution. When the solution pH was less than the critical pH, it would sharply fall, resulting in a rapid decrease of the SO2 removal rate. A theoretical model for predicting the SO2 removal rate has been developed by taking the chemical enhancement and the sulfite concentration in the liquid phase into account simultaneously.

关键词： SO2 removal bubble column reactor removalrate ammonium bicarbonate absorbent

Rigid graph-based three-dimension localization algorithm for wireless sensor networks

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Journal of Systems Engineering and Electronics 2018年第5期29卷 927-936页

作者： LUO Xiaoyuan ZHONG Wenjing li xiaolei GUAN Xinping School of Electrical Engineering Yanshan University Department of Automation Shanghai Jiao Tong University

This paper investigates the node localization problem for wireless sensor networks in three-dimension space. A distributed localization algorithm is presented based on the rigid graph. Before location, the communication radius is adaptively increasing to add the localizability. The localization process includes three steps: firstly, divide the whole globally rigid graph into several small rigid blocks; secondly, set up the local coordinate systems and transform them to global coordinate system; finally, use the quadrilateration iteration technology to locate the nodes in the wireless sensor network. This algorithm has the advantages of low energy consumption, low computational complexity as well as high expandability and high localizability. Moreover, it can achieve the unique and accurate localization. Finally, some simulations are provided to demonstrate the effectiveness of the proposed algorithm.

关键词： wireless sensor network localization rigid graph quadrilateration

A Logarithmic Decay of the Energy for the Hyperbolic Equation with Supercritical Damping

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Journal of Partial Differential Equations 2024年第2期37卷 150-165页

作者： li xiaolei GUO Bin School of Mathematics and Statistics Changchun University of Science and TechnologyChangchun 130022China School of Mathematics Jilin UniversityChangchun 130012China

We are concerned with the following quasilinear wave equation involving variable sources and supercritical damping:■Generally speaking,when one tries to use the classical multiplier method to analyze tRhe asymptotic behavior of solutions,an inevitable step is to deal with the integralΩ|ut|^(m−2)utudx.A usual technique is to apply Young’s inequality and Sobolev embedding inequality to use the energy function and its derivative to control this integral for the subcritical or critical ***,for the supercritical case,the failure of the Sobolev embedding inequality makes the classical method be *** do this,our strategy is to prove the rate of the integral RΩ|u|^(m)dx grows polynomially as a positive power of time variable t and apply the modified multiplier method to obtain the energy functional decays *** results improve and extend our previous work[12].Finally,some numerical examples are also given to authenticate our results.

关键词： Energy decay estimate asymptotic behavior p(x)-Laplacian operator supercritical damping

High-frequency dielectric properties of BSTO ceramic prepared with hydrothermal synthesized SrTiO_3 and BaTiO_3 powders

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Particuology 2009年第5期7卷 414-418页

作者： Yonghui Xing Hui liang xiaolei li liuqi Si Key LaboratoryforAdvanced Ceramics and Machining Technology of Ministry of Education Tianjin University Tianjin 300072 China Shandong Sinocera Functional Material Co. Ltd.. Shandong Dongying 257091 China

BSTO dielectric ceramic was prepared from SrTi03 and BaTi03 powders synthesized by hydrothermal method, as well as from ***.4TiO3 powder synthesized by conventional solid-state reaction. The former can be sintered at a relatively low temperature of 1120 ℃. Characterization by SEM showed that the grain shapes of both ceramics are cubical, though the grain size of the former is much smaller. Dielectric constants measured at 20℃ were shown to vary with frequency in the range from I kHz to 2 MHz and dc bias field, and further that the dielectric loss of the former to be less than 2 × 10^- 3 in the frequency range of 20 kHz to 1 MHz, much smaller than that of the latter sample. For the former, temperature dependence of dielectric constant is much flatter and there exists an extended phase transition diffusion covering a wide temperature range of Curie temperature To. The smaller grain size of the former depresses the dc bias electrical field dependence of dielectric constant. The tunability is 7% under a bias field of 0.6 kV/mm dc.

关键词： Hydrothermal method SrTiO3 BaTiO3 Dielectric properties

Extraction of Acoustic Normal Mode Depth Functions Using Range-Difference Method with Vertical linear Array Data

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Journal of Ocean University of China 2024年第4期23卷 871-882页

作者： GAO Siyu li Weilu ZHANG Yinquan li xiaolei WANG Ning College of Marine Technology Ocean University of ChinaQingdao 266100China National Marine Data and Information Service Tianjin 300171China

Data-derived normal mode extraction is an effective method for extracting normal mode depth functions in the absence of marine environmental ***,when the corresponding singular vectors become nonunique when two or more singular values obtained from the cross-spectral density matrix diagonalization are nearly equal,this results in unsatisfactory extraction outcomes for the normal mode depth *** address this issue,we introduced in this paper a range-difference singular value decomposition method for the extraction of normal mode depth *** performed the mode extraction by conducting singular value decomposition on the individual frequency components of the signal's cross-spectral density *** was achieved by using pressure and its range-difference matrices constructed from vertical line array *** proposed method was validated using simulated *** addition,modes were successfully extracted from ambient noise.

关键词： range difference depth function extraction normal mode