检索结果-南通市图书馆

Closed-loop fault detection for full-envelope flight vehicle with measurement delays

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2015年第3期28卷 832-844页

作者： wang zhaolei wang Qing Dong Chaoyang Gong Ligang School of Automation Science and Electrical Engineering Beihang University Beijing Aerospace Automatic Control Institute School of Aeronautical Science and Engineering Beihang University

Abstract A closed-loop fault detection problem is investigated for the full-envelope flight vehicle with measurement delays, where the flight dynamics are modeled as a switched system with delayed feedback signals. The mode-dependent observer-based fault detection filters and state estimation feedback controllers are derived by considering the delays＇ impact on the control system and fault detection system simultaneously. Then, considering updating lags of the controllers/filters＇ switching signals which are introduced by the delayed measurement of altitude and Mach number, an asynchronous H analysis method is proposed and the system model is further augmented to be an asynchronously switched time-delay system. Also, the global stability and desired performance of the augmented system are guaranteed by combining the switched delay-dependent Lyapunov Krasovskii functional method with the average dwell time method （ADT）, and the delaydependent existing conditions for the controllers and fault detection filters are obtained in the form of the linear matrix inequalities （LMIs）, Finally, numerical example based on the hypersonic vehicles and highly maneuverable technology （HiMAT） vehicle is given to demonstrate the merits of the proposed method.

关键词： Fault diagnosis Measurement delays Asynchronous switching Full-envelope flight vehicle Closed-loop fault detection

Asynchronous H_∞ Control for Unmanned Aerial Vehicles: Switched Polytopic System Approach

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2015年第2期2卷 207-216页

作者： zhaolei wang Qing wang Chaoyang Dong School of Automation Science and Electrical Engineering Beijing University of Aeronautics and Astronautics Beijing Aerospace Automatic Control Institute School of Aeronautical Science and Engineering Beijing University of Aeronautics and Astronautics

This study is concerned with the H∞control for the full-envelope unmanned aerial vehicles (UAVs) in the presence of missing measurements and external disturbances. With the dramatic parameter variations in large flight envelope and the locally overlapped switching laws in flight, the system dynamics is modeled as a locally overlapped switched polytopic system to reduce designing conservatism and solving complexity. Then, considering updating lags of controller's switching signals and the weighted coefficients of the polytopic subsystems induced by missing measurements, an asynchronous H∞control method is proposed such that the system is stable and a desired disturbance attenuation level is satisfied. Furthermore, the sufficient existing conditions of the desired switched parameter-dependent H∞controller are derived in the form of linear matrix inequality (LMIs) by combining the switched parameter-dependent Lyapunov function method and average dwell time method. Finally, a numerical example based on a highly maneuverable technology (HiMAT) vehicle is given to verify the validity of the proposed method. © 2014 Chinese Association of Automation.

关键词： Flight envelopes Linear matrix inequalities Lyapunov functions Numerical methods Robust control Robustness (control systems) Unmanned aerial vehicles (UAV) Vehicles

A rapid and operator-safe powder approach for latent fingerprint detection using hydrophilic Fe3O4@SiO2-CdTe nanoparticles

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2019年第7期62卷 889-896页

作者： zhaolei wang Xue Jiang Wenbin Liu Guolin Lu Xiaoyu Huang Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences Shanghai 200032 China Shanghai Key Laboratory of Crime Scene Evidence Shanghai Research Institute of Criminal Science and Technology Shanghai 200083 China

A new kind of bifunctional magnetic-fluorescent nanoparticles(NPs)with abundant carboxyls on the surface has been prepared by covalently combining glutathiose(GSH)-modified CdTe quantum dots(QDs)with Fe3O4@*** silica-coated Fe3O4NPs were functionalized with amino groups by(3-aminopropyl)triethoxysilane to provide Fe3O4@SiO2-NH2NPs,which was then chemically conjugated with GSH-modified CdTe QDs to form bifunctional magnetic-fluorescent NPs,Fe3O4@SiO2-NH-CO-CdTe-QDs *** properties and morphologies of Fe3O4@SiO2-NH-CO-CdTe-QDs NPs were investigated by FTIR,X-ray diffraction,transmission electron microscopy(TEM),absorption and fluorescence spectroscopy and vibrating sample *** images display that Fe3O4@SiO2-NH-CO-CdTe-QDsNPs possess spherical core-shell structure with a uniform size about 50 *** bifunctional NPs were found to exhibit good magnetic and strong fluorescent properties favorable for their application in the detection of latent ***,the carboxyls on the surface of NPs have good absorptions with water in air and the residues of fingerprints so as to not only avoid dust flying to protect the health of operators,but also improve the efficiency of detection.

关键词： fingerprint magnetic nanoparticle fluorescence quantum dot

Optimal Robust Fault Detection for Networked Flight Control Systems with Markovian Packet Dropouts

在线全文

学校读者我要写书评

暂无评论

Optimal Robust Fault Detection for Networked Flight Control ...

Feedback Linearization Control for Electro-hydraulic Servo System Based on Nonlinear Disturbance Observer 36

第25届中国控制与决策会议

作者： wang Qing wang zhaolei Dong Chaoyang School of Automation Science and Electrical Engineering School of Aeronautical Science and Engineering

ISBN: (纸本)9781467355322

In this article, the fault detection problem for the networked flight control systems with packet dropout is investigated. The networked flight control systems with periodic packet dropouts are treated as a varying sampling rate system. Refer to the non-periodic packet dropout that could be described as a Markov process, the varying sampling rate networked control system could be farther modeled as a discrete-time Markov jump linear system. Based on this model, considering a more general situation that the transition probabilities are partially known, a fault detection filter is established whose robust performance index is optimal. Meanwhile the corresponding fault detection problem can be transformed to an LMI optimization problem, and sufficient conditions to solve this problem are simultaneity derived. Finally, a networked flight control system is considered to validate the effectiveness and potential of the proposed method.

关键词： Fault detection Networked control systems Markovian jump systems partially known transition probabilities

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Feedback Linearization Control for Electro-hydraulic Servo S...

A comparison of the biological activities of ethyl acetate fractions from the stems and leaves of Penthorum chinense Pursh

第36届中国控制会议

作者： Shenhang wang Qi Xu Ruishi Lin Mingjun Yang Wei Zheng zhaolei wang Beijing Aerospace Automatic Control Institute

ISBN: (纸本)9781538629185

Feedback linearization control based on nonlinear disturbance observer is investigated for an electro-hydraulic servo system with external disturbances and system ***,a mathematical model of electro-hydraulic servo system is developed and a single input-output affine system form is *** the technique,based on the feedback linearization,is employed to transform the nonlinear system to an equivalent linear form,the controller of which is designed by the pole placement ***,a nonlinear disturbance observer is developed,which is a useful method for improving the system robustness and reducing the effects of disturbances and system *** simulation example shows that the proposed strategy can suppress parameter variation and exterior disturbance as well as obtaining good dynamic response.

关键词： Electro-hydraulic system feedback linearization nonlinear disturbance observer

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Frontiers of Agricultural Science and Engineering 2020年第4期7卷 505-512页

作者： zhaolei wang Kai JIANG Qinchao DING Shujun LIU Xiaobing DOU Bin DING College of Life Science Zhejiang Chinese Medical UniversityHangzhou 310053China Beijing Stomatological Hospital/School of Stomatology Capital Medical UniversityBeijing 100050China

Penthorum chinense Pursh(PCP)is a popular traditional medicinal plant in China,widely used for the treatment of a variety of liver *** it has been long recognized that the main active elements of PCP are contained in ethyl acetate fraction(EAF),little is known so far in terms of the relative effectiveness of EAF derived from the stems versus leaves of this *** the current study,we prepared EAF by reflux extraction and sequential extraction from the stems(SEAF)and leaves(LEAF)of PCP and tested their hepatoprotective *** extract rates and flavonoid contents of LEAF were higher than those of ***(>50μg·mL^(–1))prevented lipid accumulation in cells and protected against lipotoxicity injury when the concentration exceeded 25μg·mL^(–1).More than 95%free radicals released by 2,2-diphenyl-1-picrylhydrazyl(DPPH)were eliminated by 25μg·mL^(–1)SEAF and 50μg·mL^(–1)LEAF,***,EAFs(25μg·mL^(–1))also showed protective antioxidant effects,with the activity of LEAF being significantly higher than that of ***(10 mg·mL^(–1))also showed similar unspecific bacteriostatic *** comparison with SEAF,LEAF contained more flavonoids and had a higher anti-oxidation capability and for these reasons we suggest it should be better for clinical use.

关键词： antibacterial anti-oxidation lipid accumulation lipotoxicity Penthorum chinense Pursh

Effect of regularization parameters on geophysical reconstruction

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2009年第2期6卷 119-126页

作者： Zhou Hui wang zhaolei Qiu Dongling Li Guofa Shen Jinsong State Key Laboratory of Petroleum Resource and Prospecting China University of Petroleum Beijing 102249 China Key Laboratory of CNPC Geophysical Prospecting China University of Petroleum Beijing 102249 China Research Institute Bureau of Geophysical Prospecting Hebei 072751 China China University of Petroleum Beijing 102249 China

In this paper we discuss the edge-preserving regularization method in the reconstruction of physical parameters from geophysical data such as seismic and ground-penetrating radar data. In the regularization method a potential function of model parameters and its corresponding functions are introduced. This method is stable and able to preserve boundaries, and protect resolution. The effect of regularization depends to a great extent on the suitable choice of regularization parameters. The influence of the edge-preserving parameters on the reconstruction results is investigated and the relationship between the regularization parameters and the error of data is described.

关键词： Geophysical data inversion error of data regularization regularization parameters

在线全文

学校读者我要写书评

暂无评论

基于线性方程组解的T型线路行波测距

电网技术 2014年第4期38卷 1046-1050页

作者：王召磊刘明光北京交通大学电气工程学院北京市海淀区100044

目前的T型输电线路行波故障测距算法一般都是依据双端行波故障测距的原理。在深入研究行波故障测距原理和T型线路的故障测距方法的基础上,提出了综合利用T型线路的三端测量数据和线路本身的固有关系建立线性方程组的方法,并利用线性方... 详细信息

目前的T型输电线路行波故障测距算法一般都是依据双端行波故障测距的原理。在深入研究行波故障测距原理和T型线路的故障测距方法的基础上,提出了综合利用T型线路的三端测量数据和线路本身的固有关系建立线性方程组的方法,并利用线性方程组的解直接进行故障支路的判别和故障点测距。此方法突破了首先判断故障支路然后故障定位的传统思路,将其进行了统一。给出了确定的误差范围,作为故障支路识别和故障点测距的依据。该方法只利用故障电流的初始行波,便于故障的识别。仿真结果表明了该方法的正确性和精确度。

关键词：线性方程行波 T型线路故障测距小波变换

Robust Fault Detection for the Networked Flight Vehicle based on Asynchronously Switched Time-Delay Systems

在线全文

学校读者我要写书评

暂无评论

Robust Fault Detection for the Networked Flight Vehicle base...