检索结果-内蒙古大学图书馆

17th IFAC Symposium on System Identification (SYSID 2015)

作者： Qi, Chenkun Gao, Feng Zhao, Xianchao Yue, Yi Shanghai Jiao Tong Univ Sch Mech Engn State Key Lab Mech Syst & Vibrat Shanghai 200240 Peoples R China

The flexible manipulator is a spatially distributed mechanical system. An accurate model of the flexible manipulator is essential for the positioning control of the end effector. In this study, a grey box distributed parameter modeling approach is proposed for the flexible manipulator with unknown nonlinear dynamics. First, a nominal Euler-Bernoulli beam model is derived to describe the linear dynamics. To compensate unknown nonlinear dynamics, a nonlinear term is added in the nominal model. The Galerkin method is used to reduce the infinite-dimensional partial differential equation (PDE) model into a finite-dimensional ordinary differential equation (ODE) model. A neural network is designed to estimate the unknown nonlinearities from the input-output data. The effectiveness of the proposed grey box distributed parameter modeling approach is verified by the simulations on a flexible manipulator. (C) 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

关键词： flexible manipulator distributed parameter model model identification neural networks

来源：评论

学校读者我要写书评

暂无评论

Toward an Optimum Design of an Amorphous Silicon Photovoltaic/Thermal System:Simulation and Experiments

引用

Journal of Thermal Science 2023年第3期32卷 947-964页

作者： REN Xiao LI Jing LIU Weixin ZHU Chuanyong PEI Gang GONG Liang College of New Energy China University of Petroleum(East China)Qingdao 266580China Research Center for Sustainable Energy Technologies Energy and Environment InstituteUniversity of HullHU67RXUK Department of Thermal Science and Energy Engineering University of Science and Technology of ChinaHefei 230026China

Amorphous silicon photovoltaic/thermal(a-Si-PV/T)technology is promising due to the low power temperature coefficient,thin-film property,thermal annealing effect of the solar cells,and high conversion efficiency in *** design of a-Si-PV/T system is influenced by a number of thermodynamic,structural,and external *** analysis is useful for a good design of the system.A dynamic distributed parameter model is built and verified in this *** tests are carried *** impacts of operating temperature,mass flow rate,cover ratio of solar cells,heat transfer area,and frame shadow ratio on its performance are theoretically and experimentally *** results indicate that seven or eight copper tubes are suitable to achieve a high overall efficiency of the a-Si-PV/T *** frame and tilt angle shall avoid a shadow ratio of more than 8.3%during *** difference between power outputs at operating temperatures of 35℃and55℃in the first month is about 0.21%while it drops to less than 0.1%in the twelfth *** with conventional PVT systems,the a-Si-PV/T system benefits from a higher design temperature with a minor efficiency decrement.

关键词： amorphous silicon cell photovoltaic thermal system parametric analysis distributed parameter model frame shadow

来源：评论

学校读者我要写书评

暂无评论

Improved genetic algorithm-based prediction of a CO2 micro-channel gas-cooler against experimental data in automobile air conditioning system

引用

INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID 2019年 106卷 517-525页

作者： Yang, Jingye Yu, Binbin Chen, Jiangping Shanghai Jiao Tong Univ Inst Refrigerat & Cryogen Shanghai 200240 Peoples R China

For the prevailing CO2 micro-channel gas-cooler (MCGC) mathematical modeling research, a big challenge for an efficient numerical model is the trade-off between fast calculation and high-precision considering the specific properties of CO2. The main purpose of this work is to propose a regression method with multiple variables for CO2 MCGC model based on the combination of distributed parameter model (DPM) and Genetic algorithm (GA). The GA based prediction model of MCGC is established, which takes correlation coefficients and mean squared error into consideration. A test rig of CO2 MCGC is developed, and the experimental data used to validate the MCGC model are collected. The fixed-point iteration algorithm is utilized to reduce the complexity of simulation to accelerate the iteration speed. Moreover, an improved Taylor series expansion-based method for fast calculation of working fluid properties was proposed. The model precision was analyzed by comparing the prediction results with conducted experimental data. The improved CO2-to-air MCGC model enables to predict refrigerant outlet temperature and pressure drop within a maximum deviation of 1.2 degrees C and 2 kPa against the experimental data. (C) 2019 Elsevier Ltd and IIR. All rights reserved.

关键词： CO2 Micro channel gas cooler distributed parameter model Genetic algorithm Interpolation method Heat transfer performance

来源：评论

学校读者我要写书评

暂无评论

A partial differential equation model predictive control strategy:: application to autoclave composite processing

引用

COMPUTERS & CHEMICAL ENGINEERING 2004年第4期28卷 545-556页

作者： Dufour, P Michaud, DJ Touré, Y Dhurjati, PS Univ Lyon 1 LAGEP UMR 5007 CNRS F-69622 Villeurbanne France Univ Delaware Dept Chem Engn Newark DE 19716 USA Univ Orleans LVR UPRES EA 2078 F-18020 Bourges France

A general framework for a partial differential equation (PDE) model predictive control (MPC) problem is formulated. A first principle model of the system. described by a semi-linear PDE system with boundary control, is employed in a model predictive control (MPC) framework. Here, the aim is to determine, off-line (i.e. without process measurement), the theoretical optimal behavior of the process that will be used during on-line MPC. Input and output constraints are handled in the optimization task using a nonlinear programming method. This strategy is evaluated for the optimization of processing temperatures during the manufacture of thick-sectioned polymer composite laminates. The off-line optimization task consists of determining the optimal temperature profile, otherwise known as the cure cycle. Moreover, for this particular process, the existence of a feasible constrained optimization problem is discussed through the design of a constraint bound. (C) 2003 Elsevier Ltd. All rights reserved.

关键词： model predictive control distributed parameter model nonlinear programming trajectory optimization composite manufacturing autoclave curing process

来源：评论

学校读者我要写书评

暂无评论

Thermal performance analysis of SuperORV heat transfer tube at supercritical pressure

引用

JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING 2016年 29卷 488-496页

作者： Pan, Jie Li, Ran Lv, Tao Wu, Gang Xian Shiyou Univ Coll Petr Engn Xian 710065 Shaanxi Provinc Peoples R China

Super open rack vaporizer (SuperORV) is a new-type of liquefied natural gas (LNG) vaporizer whose lower half of heat transfer tubes has double tube structure. A distributed parameter model based on energy balance is developed in the present paper with the aim to simulate the thermal performance of SuperORV heat transfer tube at supercritical pressure. Corresponding empirical correlations are used to evaluate the convection heat transfer of LNG and seawater, and the heat transfer enhancement effects of inner fin and twisted tape insert are considered in computation. Good agreement between calculated and experimental data implies the calculation model is reliable. On this basis, the temperature and ice thickness profiles along the heat transfer tube are obtained by numerical solution with or without ice layer presence, the thermal performance of heat transfer tube is analyzed, and the effects of operating parameters and heat transfer enhancement techniques on the thermal performance are discussed. The results indicate that both the operating parameters and the heat transfer enhancement techniques have great influence on the thermal performance, including required minimum tube length, ice thickness and length of formed ice layer. The heat transfer enhancement techniques can improve the heat transfer performance markedly, and the required tube length is reduced by 47.7% while both inner fin and twisted tape insert are applied. (C) 2016 Elsevier B.V. All rights reserved.

关键词： LNG SuperORV Heat transfer tube distributed parameter model Thermal performance Supercritical pressure

来源：评论

学校读者我要写书评

暂无评论

Current differential protection principle of HVDC transmission system

引用

IET GENERATION TRANSMISSION & DISTRIBUTION 2017年第5期11卷 1286-1292页

作者： Gao, Shu-ping Liu, Qi Song, Guo-bing Xian Univ Sci & Technol Coll Elect & Control Xian 710054 Shaanxi Peoples R China Xi An Jiao Tong Univ Coll Elect Engn Xian 710049 Shaanxi Peoples R China Shaanxi Elect Power Design Inst Co Ltd China Energy Engn Grp Xian 710054 Shaanxi Peoples R China

Traditional high-voltage DC (HVDC) current differential protection has problems on identifying fault current and has long delay. In this study, a novel current differential protection principle for HVDC transmission lines is proposed. By the adoption of distributed parameter model, differential current criterion is formed at a selected point on the transmission line. When fault occurs on DC line, setting point differential current reaches a high value. When no fault occurs or fault occurs outside the DC line, setting point differential current reaches a small value. Comparing with the traditional current differential protection, the proposed principle eliminates the impact of distributed capacitive current and has no requirement of delay. Comparing with travelling wave protection, fault identification can be performed during both transient and steady states, and the proposed method has reasonable sampling frequency requirements and has high reliability. Simulation analysis shows that the proposed principle identifies faults reliably and rapidly. The proposed principle is theoretically novel and practically applicable.

关键词： HVDC power transmission power transmission protection power transmission lines current differential protection HVDC transmission system HVDC transmission lines distributed parameter model distributed capacitive current travelling wave protection fault identification

来源：评论

学校读者我要写书评

暂无评论

A Novel Fault-Location Method for HVDC Transmission Lines

引用

IEEE TRANSACTIONS ON POWER DELIVERY 2010年第2期25卷 1203-1209页

作者： Suonan, Jiale Gao, Shuping Song, Guobing Jiao, Zaibin Kang, Xiaoning Xi An Jiao Tong Univ Dept Elect Engn Xian 710049 Shanxi Peoples R China

This paper presents a method for locating faults on HVDC transmission lines using two terminal data. Different from those based on the traveling wave principle, the new fault-location algorithm can use any section of the postfault data to locate faults. The proposed method is developed based on the distributed parameter line model in which the voltage distribution over the line can be obtained from the voltage and current measurements at both terminals and point where fault occurs can be identified from the calculated voltage distribution. The fault-location algorithm is performed in time domain and thus a short data window is sufficient for it to achieve satisfactory accuracy in practice. The proposed algorithm is simulated using data of the frequency-dependent line model in EMTDC and data of an existing HVDC line as well. The simulations have shown that this method is valid and is capable of locating the faults occurring on HVDC transmission lines quickly and accurately.

关键词： distributed parameter model fault location HVDC transmission line relay protection two-terminal electrical measurements

来源：评论

学校读者我要写书评

暂无评论

Regenerative Effects of Orthogonal Chip Dimensions on Turning Stability of Thin-Wall Workpiece-Tool Coupled Dynamics

引用

IEEE-ASME TRANSACTIONS ON MECHATRONICS 2022年第5期27卷 3601-3612页

作者： Guo, Jiajie Lee, Kok-Meng Yu, Man Ma, Haifeng Xiong, Zhenhua Huazhong Univ Sci & Technol State Key Lab Digital Mfg Equipment & Technol Wuhan 430074 Peoples R China Huazhong Univ Sci & Technol Sch Mech Sci & Engn Wuhan 430074 Peoples R China Georgia Inst Technol Woodruff Sch Mech Engn Atlanta GA 30332 USA Shanghai Jiao Tong Univ Sch Mech Engn State Key Lab Mech Syst & Vibrat Shanghai 200240 Peoples R China

Machining stability of thin-wall (flexible) components plays an important role in manufacturing efficiency and final product qualities, where machining dynamics are characterized by infinite degrees of freedom distributed in both the time and spatial domains. This article presents a distributed parameter method to model the coupled workpiece-cutting tool (WP-CT) dynamics and investigate the regenerative effects of both depth and width of cut on turning stability. By accounting for the regenerative effects in both radial and axial directions of a flexible disk component, this method relaxes a commonly made assumption that the regenerative chip of the coupled WP/CT dynamics varies in the direction of chip thickness. Formulated using the energy method, the dynamic model that requires only a few dominant modes is developed to construct 3-D stability lobe diagrams in terms of width/depth of cut, rotational speed, and cutting position. The proposed modeling method, which offers a means to identify parameters of a coupled WP-CT system and predict the spatially distributed vibrations and their effects on machining stability, has been analyzed in simulation and validated with experiments.

关键词： distributed parameter model flexible workpiece (WP) machining dynamics stability lobe diagram thin-wall component

来源：评论

学校读者我要写书评

暂无评论

A STUDY ON DYNAMIC CHARACTERISTICS OF PLATE-FIN RECUPERATOR IN HIGH-TEMPERATURE GAS-COOLED REACTOR CLOSED CYCLE

引用

NUCLEAR TECHNOLOGY 2010年第3期169卷 205-217页

作者： Ding, Ming Yang, Xiaoyong Wang, Jie Harbin Engn Univ Coll Nucl Sci & Technol Harbin 150001 Peoples R China Tsinghua Univ Inst Nucl & New Energy Technol Beijing 100084 Peoples R China

A recuperator is a key component and plays an important role in the high-temperature gas-cooled reactor combined with gas turbine (HTGR-GT) system. A distributed parameter model was proposed to study the dynamic characteristics of the recuperator of the HTGR-GT cycle, and this model was solved using an implicit arithmetic. Basic characteristics of the recuperator were analyzed using responses of the recuperator to step disturbances of temperature and mass flow. The response of the recuperator to the temperature disturbances has two different characteristic times tau(1) and tau(2) depending on the relation between the response and the disturbance. The response of the recuperator to mass flow disturbance has a characteristic time tau(4) that is between tau(1) and tau(2). An example of coupled disturbance of temperature and mass flow was simulated by the distributed parameter model. This example shows the influence of the three characteristic times to the dynamic characteristics of the recuperator. When the system power of HTGR-GT is regulated slowly, the core temperature distribution of the recuperator hardly varies. However, when the electric load of the system is rejected from full power, the core temperature, especially in the front of the recuperator, suffers from a drastic change in temperature.

关键词： distributed parameter model dynamic characteristics plate-fin recuperator

来源：评论

学校读者我要写书评

暂无评论

Correction factor of lumped parameter model for linearly tapered piezoelectric cantilever

引用

JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES 2022年第3期33卷 474-488页

作者： Ismail, Mai R. Omar, Farag K. Ajaj, Rafic Ghodsi, Mojtaba United Arab Emirates Univ Dept Mech Engn Al Ain U Arab Emirates Khalifa Univ Sci & Technol Dept Aerosp Engn Abu Dhabi U Arab Emirates Univ Portsmouth Sch Energy & Elect Engn Portsmouth Hants England

distributed parameter model (DPM) gives an accurate representation of the vibration response of piezoelectric cantilevers. Nevertheless, lumped parameter model (LPM) has been widely used because of its simple mathematical representation. However, researchers developed a correction factor for LPM because of its inaccurate power output prediction of the piezoelectric harvesters. The developed correction factors were limited to the rectangular and exponentially tapered piezoelectric beams because the DPM of other shaped beams are rather complicated to derive. This paper presents a correction factor for linearly tapered piezoelectric cantilever beam using a finite element model (FEM) approach. Validation of the developed FEM is accomplished using two analytical models from literature of rectangular and exponentially tapered shapes with tip mass. Results show an excellent agreement between the FEM and the related DPM. The FEM of a linearly tapered piezoelectric cantilever is then built and the error of using the uncorrected LPM for different tapered ratios is investigated. Correction factors of different taper ratios subjected to various tip masses are developed. Comparisons between the corrected LPM and the FEM verify the estimation of the correction factor. Results show that FEM approach can be used to enhance the accuracy of LPM of piezoelectric cantilever harvesters.

关键词： Tapered piezoelectric cantilever correction factor lumped parameter model distributed parameter model finite element model tip mass effect

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：