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Observer-Based Adaptive Fuzzy Tracking Control Using Integral Barrier Lyapunov Functionals for A Nonlinear System With Full State Constraints

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IEEE/CAA Journal of Automatica Sinica 2021年第3期8卷 617-627页

作者： Wei Zhao yanjun liu Lei liu School of Electrical Engineering Liaoning University of TechnologyJinzhou 121001China College of Science Liaoning University of TechnologyJinzhou 121001China

A new fuzzy adaptive control method is proposed for a class of strict feedback nonlinear systems with immeasurable states and full *** fuzzy logic system is used to design the approximator,which deals with uncertain and continuous functions in the process of backstepping *** use of an integral barrier Lyapunov function not only ensures that all states are within the bounds of the constraint,but also mixes the states and errors to directly constrain the state,reducing the conservativeness of the constraint satisfaction *** that the states in most nonlinear systems are immeasurable,a fuzzy adaptive states observer is constructed to estimate the unknown *** with adaptive backstepping technique,an adaptive fuzzy output feedback control method is *** proposed control method ensures that all signals in the closed-loop system are bounded,and that the tracking error converges to a bounded tight set without violating the full state *** simulation results prove the effectiveness of the proposed control scheme.

关键词： Adaptive control backstepping design integral barrier Lyapunov function(iBLF) states observer

The Ground State Solutions for Kirchhoff-Schrodinger Type Equations with Singular Exponential Nonlinearities in R^(N)

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Chinese Annals of Mathematics,Series B 2022年第4期43卷 549-566页

作者： yanjun liu Chungen liu School of Mathematical Sciences Chongqing Normal UniversityChongqing 401331China School of Mathematics and Information Science Guangzhou UniversityGuangzhou 510006China

In this paper,the authors consider the following singular Kirchhoff-Schrodinger problem M(∫_(R^(N))|∇u|^(N)+V(x)|u|^(N)dx)(−Δ_(N)u+V(x)|u|^(N-2)u)=f(x,u)/|x|^(η)in R^(N),(P_(η))where 0<η 详细信息

In this paper,the authors consider the following singular Kirchhoff-Schrodinger problem M(∫_(R^(N))|∇u|^(N)+V(x)|u|^(N)dx)(−Δ_(N)u+V(x)|u|^(N-2)u)=f(x,u)/|x|^(η)in R^(N),(P_(η))where 0<η

关键词： Ground state solutions Singular elliptic equations Critical exponential growth Kirchhoff-Schrodinger equations Singular Trudinger-Moser inequality

Minimal Non-nilpotent and Locally Nilpotent Fusion Systems

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Algebra Colloquium 2016年第3期23卷 455-462页

作者： Jun Liao yanjun liu School of Mathematical Sciences Peking University Beijing 100871 China College of Mathematics and Information Science Jiangxi Normal University Nanchang 330022 China

The main purpose of this note is to show that there is a one-to-one corre- spondence between minimal non-nilpotent （resp., locally nilpotent） saturated fusion sys- tems and finite p J-core-free p-constrained minimal... 详细信息

关键词： saturated fusion system minimal non-nilpotent locally nilpotent p-con-strained

VOCs released from municipal solid waste at the initial decomposition stage: Emission characteristics and an odor impact assessment

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Journal of Environmental Sciences 2020年第12期32卷 143-150页

作者： yanjun liu Huiyuan Yang Wenjing Lu School of Chemical&Environmental Engineering China University of Mining&TechnologyBeijing 100083China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China School of Environment Tsinghua UniversityBeijing 100084China

The nuisance from odor caused by municipal solid waste(MSW) is resulting in a growing number of public complaints and concerns. Odor pollution occurs in the initial decomposition stage of MSW, including waste collection, transportation and early pre-treatment. Furthermore, decomposition takes place in waste facilities that are often close to living areas, which can result in odor impacts on local inhabitants. However, this aspect of odor impact from MSW has not been well studied. In the current study, lab-scale waste cells were designed to simulate MSW storage conditions in the early stage. The characteristics of VOCs emissions with different waste compositions were analyzed. The odor concentration( CO, non-dimensional) method and odor intensity were used for the assessment of odor. Ethanol was the substance with highest emission rate. The release rate of VOCs increased with the growth easily biodegradable waste(EBW). VOCs emissions was reduced by 25% when the proportion of EBW decreased from 60% to 45%. Methyl sulfide, ethanol, dimethyl disulfide and ethyl acetate were identified as typical odorants. The EBW proportion in waste is the main factor significantly influencing odor pollution. The CO was 244.51 for the 60% EBW condition, which was only 61.46 for 15% EBW condition. These study results provide important information for the implementation of a garbage sorting policy and the monitoring of odor pollution from waste management.

关键词： Municipal solid waste(MSW) Initial decomposition stage Volatile organic compounds(VOCs) Odor impact assessment Odor concentration(CO)

Adaptive neural network tracking design for a class of uncertain nonlinear discrete-time systems with dead-zone

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Science China(Information Sciences) 2014年第3期57卷 276-287页

作者： liu yanjun liu Lei TONG ShaoCheng College of Science Liaoning University of Technology

In this paper,the stability and control issues of a class of uncertain nonlinear discrete-time systems in the strict feedback form are *** dead-zone input in the systems,whose property is non-symmetric and discretized,is *** unknown functions in the systems are approximated by using the radial basis function neural networks(RBFNNs).Backstepping design procedure is employed in the controller and the adaptation laws *** analysis method is utilized to prove the stability of the closed-loop system.A simulation example is given to illustrate the efectiveness of the proposed approach.

关键词： adaptive control RBF neural network non-symmetric dead-zone backstepping design uncertain nonlinear systems

A Mathematical Model of Heat Transfer in Problems of Pipeline Plugging Agent Freezing Induced by Liquid Nitrogen

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Fluid Dynamics & Materials Processing 2022年第3期18卷 775-788页

作者： Yafei Li yanjun liu Southwest Petroleum University Chengdu610500China

A mathematical model for one-dimensional heat transfer in pipelines undergoing freezing induced by liquid nitrogen is *** basic premise of this technology is that the content within a pipeline is frozen to form a plug or two plugs at a position upstream and downstream from a location where work a modification or a repair must be *** on the variable separation method,the present model aims to solve the related coupled heat conduction and moving-boundary phase change *** experiment with a 219 mm long pipe,where water was taken as the plugging agent,is presented to demonstrate the relevance and reliability of the proposed model(results show that the error is within 18%).Thereafter,the model is applied to predict the cooling and freezing process of pipelines with different inner diameters at different liquid nitrogen refrigeration temperatures when water is used as the plugging agent.

关键词： Pipeline freezing and plugging liquid nitrogen refrigeration heat transfer model transient temperature field phase change prediction

Numerical Study of Two-Winged Insect Hovering Flight

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Advances in Applied Mathematics and Mechanics 2009年第4期1卷 481-509页

作者： yanjun liu Nansheng liu Xiyun Lu Department of Modern Mechanics University of Science and Technology of ChinaHefeiAnhui 230026China

The two-winged insect hovering flight is investigated numerically using the lattice Boltzmann method(LBM).A virtual model of two elliptic foils with flapping motion is used to study the aerodynamic performance of the insect hovering flight with and without the effect of ground *** studies have been carried out by changing some parameters of the wing kinematics,including the stroke amplitude,attack angle,and the Reynolds number for the insect hovering flight without ground effect,as well as the distance between the flapping foils and the ground surface when the ground effect is *** influence of the wing kinematic parameters and the effect of the ground surface on the unsteady forces and vortical structures are *** unsteady forces acting on the flapping foils are verified to be closely associated with the time evolution of the vortex structures,foil translational and rotational accelerations,and interaction between the flapping foils and the existed vortical *** unsteady mechanisms of lift production are identified by examining the vortical structures around the flapping *** results obtained in this study provide some physical insight into the understanding of the aerodynamics and flow structures for the insect hovering flight.

关键词： Insect hovering flight lattice Boltzmann method ground effect unsteady force vortical structure

Complementarity via Minimum Error Measurement in a Two-Path Interferometer

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Chinese Physics Letters 2019年第5期36卷 12-16页

作者： Junzhao liu yanjun liu Jing Lu Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center of Quantum Effects and ApplicationsHunan Normal UniversityChangsha 410081

We study the fringe visibility and the which-path information(WPI) of a general Mach-Zehnder interferometer with an asymmetric beam splitter(BS). A minimum error measurement in the detector is used to extract the WPI. Both the fringe visibility V and the WPI I_(path) are affected by the initial state of the photon and the second asymmetric BS. The condition in which the WPI takes the maximum is obtained. The complementarity relationship V^2 + I_(path)~2 ≤ 1 is found, and the conditions for equality are also presented.

关键词： WPI Complementarity via Minimum Error Measurement in a Two-Path Interferometer MZI

Design of Full-Ocean-Depth Self-Floating Sampler and Analysis of Factors Affecting Core Penetration Depth

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Journal of Ocean University of China 2020年第5期19卷 1094-1102页

作者： REN Yugang liu yanjun DING Zhongjun liu Baohua ZHANG Jianhua School of Mechanical Engineering Shandong UniversityJinan 250061China National Deep Sea Center Qingdao 266237China Institute of Marine Science and Technology Shandong UniversityQingdao 266237China Science and Technology on Underwater Vehicle Laboratory Harbin Engineering UniversityHarbin 150001China

The hadal zone(ocean depths of 6 – 11 km) is one of the least-understood habitats on Earth because of its extreme conditions such as high pressure, darkness, and low temperature. With the development of deep-sea vehicles such as China's 7000 m manned submersible Jiaolong, abyssal science has received greater attention. For decades, gravity-piston corers have been widely used to collect loose subsea-sediment long-core samples. However, the weight and length of the gravity sampler cables and the operating environment limit sampling capacity at full ocean depths. Therefore, a new self-floating sediment sampler with a spring-loaded auto-trigger release and that incorporates characteristics from traditional gravity-driven samplers is designed. This study analyzes the process by which a gravity-piston corer penetrates the sediment and the factors that affect it. A formula for obtaining the penetration depth is deduced. A method of optimizing the sampling depth is then developed based on structure design and parametric factor modeling. The parameters considered in the modeling include the sampling depth, balance weight, ultimate stress friction coefficient, dimensions of the sampler, and material properties. Thus, a new deep-sea floating parametric sampler designed based on virtual prototyping is proposed. Accurate values for all the design factors are derived from calculations based on the conservation of energy with penetration depth, analyses of the factors affecting the penetration depth, and analyses of the pressure bar stability. Finally, experimental data are used to verify the penetration-depth function and to provide theoretical guidance for the design of sediment samplers.

关键词： full-ocean-depth sampling sediment sampler factor parameter design hadal science