检索结果-南通市图书馆

nonlinear dynamics and station-keeping control of a rotating tethered satellite system in halo orbits

在线全文

学校读者我要写书评

暂无评论

Chinese journal of Aeronautics 2013年第5期26卷 1227-1237页

作者： Liu Gang Huang j.ng Ma guangfu Li Chuanjiang Department of Control Science and Engineering Harbin Institute of Technology

The dynamics of a rotating tethered satellite system （TSS） in the vicinity of libration points are highly nonlinear and inherently unstable. In order to fulfill the station-keep control of the rotating TSS along halo orbits, a nonlinear output tracking control scheme based on the θ- D technique is proposed. Compared with the popular time-variant linear quadratic regulator （LQR） controller, this approach overcomes some limitations such as on-line computations of the algebraic Riccati equation. Besides, the obtained nonlinear suboptimal controller is in a closed form and easy to implement. numerical simulations show that the TTS trajectories track the periodic reference orbit with low energy consumption in the presence of both tether and initial injection errors. The axis of rotation can keep pointing to an inertial specific object to fulfill an observation mission. In addition, the thrusts required by the controller are in an acceptable range and can be implemented through some low-thrust propulsion devices.

关键词： Halo orbit Restricted three-body problem Station-keeping control Suboptimal control Tethered satellite system

Weighted Multi-sensor Data Level Fusion Method of Vibration Signal Based on Correlation Function

在线全文

学校读者我要写书评

暂无评论

Chinese journal of Mechanical Engineering 2011年第5期24卷 899-904页

作者： BIn guangfu jIAnG Zhinong LI Xuej.n DHILLOn B S Diagnosis and Self-recovery Engineering Research Center Beijing University of Chemical Technology Beijing 100029 China Hunan Provincial Key Laboratory of Health Maintenance for Mechanical Equipment Hunan University of Science and Technology Xiangtan 411201 China Department of Mechanical Engineering University of Ottawa 161 Louis Pasteur Ottawa K1B 6N5 Canada

As the differences of sensor＇s precision and some random factors are difficult to control,the actual measurement signals are far from the target signals that affect the reliability and precision of rotating machinery fault *** traditional signal processing methods,such as classical inference and weighted averaging algorithm usually lack dynamic adaptability that is easy for trends to cause the faults to be misjudged or left *** enhance the measuring veracity and precision of vibration signal in rotary machine multi-sensor vibration signal fault diagnosis,a novel data level fusion approach is presented on the basis of correlation function analysis to fast determine the weighted value of multi-sensor vibration *** approach doesn＇t require knowing the prior information about sensors,and the weighted value of sensors can be confirmed depending on the correlation measure of real-time data tested in the data level fusion *** gives greater weighted value to the greater correlation measure of sensor signals,and vice *** approach can effectively suppress large errors and even can still fuse data in the case of sensor failures because it takes full advantage of sensor＇s own-information to determine the weighted ***,it has good performance of anti-jamming due to the correlation measures between noise and effective signals are usually *** the simulation of typical signal collected from multi-sensors,the comparative analysis of dynamic adaptability and fault tolerance between the proposed approach and traditional weighted averaging approach is ***,the rotor dynamics and integrated fault simulator is taken as an example to verify the feasibility and advantages of the proposed approach,it is shown that the multi-sensor data level fusion based on correlation function weighted approach is better than the traditional weighted average approach with respect to fusion precision and dynamic ***,the approac

关键词： vibration signal multi-sensor data level fusion correlation function weighted value

Three-dimensional finite-time cooperative guidance for multiple missiles without radial velocity measurements

在线全文

学校读者我要写书评

暂无评论

Chinese journal of Aeronautics 2019年第5期32卷 1294-1304页

作者： Teng LYU Chuanjiang LI Yanning GUO guangfu MA Department of Control Science and Engineering Harbin Institute of Technology

In order to simultaneously attack a target with impact angle constraint in threedimensional(3-D) space, a novel distributed cooperative guidance law for multiple missiles under directed communication topologies is proposed without radial velocity measurements. First, based on missiles-target 3-D relative motion equations, the multiple missiles cooperative guidance model with impact angle constraint is constructed. Then, in Line-of-Sight(LOS) direction, based on multiagent system cooperative control theory, one guidance law with directed topologies is designed with strict proof, which can guarantee finite time consensus of multiple missiles' impact times. next, in elevation direction and azimuth direction of LOS, based on homogeneous system stability theory and integral sliding mode control theory, two guidance laws are proposed respectively with strict proof, which can guarantee LOS angles converge to desired values and LOS angular rates converge to zero in finite time. Finally, the effectiveness of the designed cooperative guidance law is demonstrated through simulation results.

关键词： 3-D cooperative guidance Directed communication topologies Finite time Impact angle constraint Radial velocity measurements

Thermodynamic and Optical Properties of CuAlO_2 under Pressure from First Principle

在线全文

学校读者我要写书评

暂无评论

journal of Wuhan University of Technology(Materials Science) 2015年第6期30卷 1338-1344页

作者：张丽琴程艳 jI guangfu College of Physics and Electronic Information Huaibei Normal University College of Physical Science and Technology Sichuan University Laboratory for Shock Wave and Detonation Physics Research Institute of Fluid Physics Chinese Academy of Engineering Physics

The structural stability, thermodynamic and optical properties of delafossite CuAlO2 were investigated using the norm-conserving pseudopotential technique based on the fi rst-principle density-functional theory. The ground-state properties obtained by minimizing the total energy were in favorable agreement with previous works. By using the quasi-harmonic Debye model, the thermodynamic properties including the Debye temperature QD, heat capacity CV, thermal expansion coeffi cient a, and Grüneisen parameter g were successfully obtained in the temperature range from 0 to 1 000 K and pressure range from 0 to 80 GPa, respectively. The optical properties including dielectric function e（v）, absorption coeffi cient a（v）, refl ectivity coeffi cient R（v）, and refractive index n（v） were also calculated and analyzed.

关键词： first principle CuAlO2 thermodynamic properties optical properties

Data-driven model-free adaptive attitude control of partially constrained combined spacecraft with external disturbances and input saturation

在线全文

学校读者我要写书评

暂无评论

Chinese journal of Aeronautics 2019年第5期32卷 1281-1293页

作者： Han GAO guangfu MA Yueyong LYU Yanning GUO Department of Control Science and Control Engineering Harbin Institute of Technology

This study presents an improved data-driven Model-Free Adaptive Control(MFAC)strategy for attitude stabilization of a partially constrained combined spacecraft with external disturbances and input saturation. First, a novel dynamic linearization data model for the partially constrained combined spacecraft with external disturbances is established. The generalized disturbances composed of external disturbances and dynamic linearization errors are then reconstructed by a Discrete Extended State Observer(DESO). With the dynamic linearization data model and reconstructed information, a DESO-MFAC strategy for the combined spacecraft is proposed based only on input and output data. next, the input saturation is overcome by introducing an antiwindup compensator. Finally, numerical simulations are carried out to demonstrate the effectiveness and feasibility of the proposed controller when the dynamic properties of the partially constrained combined spacecraft are completely unknown.

关键词： Attitude control Combined spacecraft Data-driven control Discrete Extended State Observer(DESO) Input saturation

n‑Doped Graphene‑Decorated niCo Alloy Coupled with Mesoporous niCoMoO nano‑sheet Heteroj.nction for Enhanced Water Electrolysis Activity at High Current Density

在线全文

学校读者我要写书评

暂无评论

nano-Micro Letters 2021年第5期13卷 77-89页

作者： guangfu Qian j.nli Chen Tianqi Yu Lin Luo Shibin Yin College of Chemistry and Chemical Engineering MOE Key Laboratory of New Processing Technology for Nonferrous Metals and MaterialsState Key Laboratory of Processing for Non‑Ferrous Metal and Featured MaterialsGuangxi University100 Daxue RoadNanning 530004P.R.China

Developing highly effective and stable non-noble metalbased bifunctional catalyst working at high current density is an urgent issue for water electrolysis(WE).Herein,we prepare the n-doped graphene-decorated niCo alloy coupled with mesoporous niCoMoO nano-sheet grown on 3D nickel foam(niCo@C-niCoMoO/nF)for water ***@C-niCoMoO/nF exhibits outstanding activity with low overpotentials for hydrogen and oxygen evolution reaction(HER:39/266 mV;OER:260/390 mV)at±10 and±1000 mA cm^(−2).More importantly,in 6.0 M KOH solution at 60℃ for WE,it only requires 1.90 V to reach 1000 mA cm−2 and shows excellent stability for 43 h,exhibiting the potential for actual *** good performance can be assigned to n-doped graphene-decorated niCo alloy and mesoporous niCoMoO nano-sheet,which not only increase the intrinsic activity and expose abundant catalytic activity sites,but also enhance its chemical and mechanical *** work thus could provide a promising material for industrial hydrogen production.

关键词： n-doped graphene-decorated niCo alloy Catalyst Mesoporous nano-sheet Water electrolysis High current density

Insight into the Structural Requirements of Protoporphyrino- gen Oxidase Inhibitors： Molecular Docking and CoMFA of Di- phenyl Ether, Isoxazole Phenyl, and Pyrazole Phenyl Ether

在线全文

学校读者我要写书评

暂无评论

Chinese journal of Chemistry 2013年第9期31卷 1153-1158页

作者： Shenggang Yang Gefei Hao Franck E Dayan Patrick j. Tranel guangfu Yang Key Laboratory of Pesticide & Chemical Biology Ministry of Education College of Chemistry Central China Normal University Wuhan Hubei 430079 China USDA/ARS Natural Products Utilization Research Unit P.O. Box 8048 University MS 38677 USA Department of Crop Sciences University of lllinois Urbana IL 61801 USA

Protoporphyrinogen oxidase （PPO, EC 1.***.3.4） is one of the most significant targets for a large family of in- hibitors that may be used as herbicide, bactericide, fungicide, or photosensitizing activator to treat cancer through photodynamic therapy （PDT）. Molecular docking and CoMFA were combined in a multistep framework with the ultimate goal of identifying important factor contributing to the activity of PPO inhibitors. As a continuation of the previous research work on the development of new PPO inhibitors, the bioassay results indicated that good PPO in- hibitors were discovered in all of the three chemical series with ICs0 values ranging from 0.010 to 0.061 pmol·L ^-1. Using the crystal structure of tobacco mitochondrial PPO （mtPPO） as template, all the compounds were docked into the enzyme active site. The docking pose of each compound was subsequently used in a receptor-based alignment, leading to the development of a significant CoMFA model with r^2 value of 0.98 and q^2 （cross validation r^2） value of 0.63. This novel multistep framework gives insight into the and it can be extended to other classes of PPO inhibitors. In be particularly applicable in virtual screening procedures. structural characteristics for the binding of inhibitors, addition, the simplicity of the proposed approach may

关键词： protoporphyrinogen oxidase Quantitative Structure-Activity Relationship (QSAR) Comparative Mo-lecular Field Analysis (CoMFA) diphenyl ether isoxazole phenyl pyrazole phenyl ether

Attitude control without angular velocity measurement for flexible satellites

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese journal of Aeronautics 2018年第6期31卷 1345-1351页

作者： Qinghua ZHU guangfu MA Xiaoting WAnG Aiguo WU Department of Control Science and Control Engineering Harbin Institute of Technology Harbin 150001 China Shanghai Aerospace Control Technology Institute Shanghai 201109 China Harbin Institute of Technology Shenzhen Graduate School Shenzhen 518055 China Shanghai Key Laboratory of Aerospace Intelligent Control Technology Shanghai 201109 China

In this paper, by using quaternion models, the problem of attitude control is investigated for a class of flexible satellites. Two control laws are presented for the considered flexible satellite models to guarantee convergence of the closed-loop systems without using angular velocity measurement. One is in the form of a partial state feedback for the case where the modal variable is available, and the other is in the form of an observer-based partial state feedback for the case where the modal variable cannot be measured. Finally, an example is employed to illustrate the effectiveness of the proposed control laws.

关键词： Attitude control Flexible satellites Modal variables Quaternion models Passivity

Fast fixed-time three-dimensional terminal guidance with non-concave trajectory constraint

在线全文

学校读者我要写书评

暂无评论

Chinese journal of Aeronautics 2024年第3期37卷 208-218页

作者： Youmin GOnG Yanning GUO Yueyong LYU Dongyu LI guangfu MA Department of Control Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Cyber Science and Technology Beihang UniversityBeijing 100191China

Focusing on the non-concave trajectory constraint,a sliding-mode-based nonsingular feedback fast fixed-time three-dimensional terminal guidance of rotor unmanned aerial vehicle landing,planetary landing and spacecraft rendezvous and docking terminal phase with external disturbance is investigated in this ***,a fixed-time observer based on real-time differentiator is developed to compensate for the external disturbance,whose estimation error can converge to zero after a time independent of the initial ***,a sliding surface ensuring fixed-time convergence is *** sliding surface can guarantee that the vehicle achieves a non-concave trajectory,which is better for avoiding collision and maintaining the visibility of the landing site or docking ***,the nonsingular guidance ensuring the fixed-time convergence of the sliding surface is proposed,which is continuous and chatter *** last,three numerical simulations of Mars landing are performed to validate the effectiveness and correctness of the designed scheme.

关键词： Three-dimensional Terminal guidance non-concave trajectory constraint Fast fixed-time control Sliding mode control