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Design and implementation of decoupled compensation for a twin rotor multiple-input and multiple-output system

IET CONTROL THEORY AND APPLICATIONS 2013年第2期7卷 282-289页

作者： Pradhan, Jatin Kumar Ghosh, Arun IIT Bhubaneswar Sch Elect Sci Bhubaneswar 751013 Orissa India

This study achieves compensation of a physical twin rotor multiple-input and multiple-output system in two steps: (i) input-output decoupling its transfer function model, obtained by linearising its non-linear model around an operating point, using an open-loop, minimal precompensator and (ii) effecting 2-degree of freedom single-input and single-output (SISO) compensations for the resulting SISO-decoupled units. While step (i) ensures decoupling in the responses, the other performances (such as robustness, tracking, disturbance rejection, etc.) can be achieved using SISO compensations in step (ii) above. The performances of the compensated system in respect of decoupling, loop robustness and disturbance rejection are verified through simulations and experiments. The results are also compared with the existing ones.

关键词： compensation control system synthesis MIMO systems nonlinear control systems open loop systems transfer functions loop robustness disturbance rejection SISO-decoupled units single-input and single-output compensations 2-degree of freedom minimal precompensator open-loop system operating point nonlinear model transfer function model input-output decoupling twin rotor multiple-input and multiple-output system decoupled compensation

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Evaluating Infiltration Mechanisms Using Breakthrough Curve and Mean Residence Time

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WATER RESOURCES MANAGEMENT 2013年第13期27卷 4579-4590页

作者： Qu Simin Wang Tao Bao Weimin Shi Peng Jiang Peng Zhou Minmin Yu Zhongbo Hohai Univ State Key Lab Hydrol Water Resources & Hydraul En Nanjing 210098 Jiangsu Peoples R China Hohai Univ Coll Water Resources & Hydrol Nanjing 210098 Jiangsu Peoples R China HydroChina Chengdu Engn Corp Chengdu Peoples R China Univ Nevada Dept Geosci Las Vegas NV 89154 USA

Determination of infiltration mechanism is crucial for the calculation of infiltration flux in the soil which would influence the water balance computation. Two infiltration experiments with different isotopic compositions of rainfall were conducted to analyze the infiltration type by measuring isotopic concentrations (deuterium and oxygen 18) of collected outflow water samples. models with three transfer functions were used to simulate the isotopic variation of outflows in a soil column. The model performance was evaluated with the comparison of computed and observed isotopic values of outflow. Breakthrough curve based on the isotopic composition of rainfall, initial soil water and outflow, and mean residence time estimated on the best fitting transfer function model were applied to identify the infiltration type in the soil. The results show that infiltration type determination using the comparison between estimated and observed mean residence time and breakthrough curve are similar. Furthermore, we found that soil structure and isotope measurement error affected the determination of mean residence time. Results from this study may provide a framework for describing the infiltration processes in the soil column.

关键词： transfer function model Mean residence time Infiltration type Breakthrough curve

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Mathematical modeling for SnO₂ Gas Sensor Based on Second-Order Response

Mathematical Modeling for SnO<sub>2</sub> Gas Sensor Based o...

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IEEE Symposium on Industrial Electronics and Applications (ISIEA)

作者： Moshayedi, Ata Jahangir Toudeshki, Arash Gharpure, Dayamanti C. Univ Pune Dept Elect Sci Pune 411007 Maharashtra India Univ Putra Malaysia Fac Engn Ctr Adv Power & Energy Res Upm Serdang 43400 Selangor Malaysia

ISBN: (纸本)9781479911233

Sensors, work on the entrance gate for exploring dynamic environments and system response. The sensor behavior plays an important role in system modeling. Therefore, finding the mathematical model, which can describe the sensor response with maximum information over time in different environments and situations, is necessary. This paper, attempts to model the optimal transfer function of the SnO2 type gas sensor (TGS 813) for transient response and steady-state zones, based on the acquired data of the sensor. The model could be used to obtain the mathematical equation for the response, as a transfer function based on different concentrations, for the specific temperature and humidly. The data analysis has been done with Matlab software, and Genetic algorithm is further used to optimize the transfer function parameters. Moreover, the effect of variation in concentration on the transfer function coefficients has been explored. The results show that the modeling can be helpful for sensor response behavior simulation as well as physical and chemical reaction investigation.

关键词： gas sensor TGS 813 transfer function model transient estimation genetic algorithm (GA) second-order response

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Time series outlier and intervention analysis: Irrigation management influences on soil water content in silty loam soil

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AGRICULTURAL WATER MANAGEMENT 2012年 111卷 105-114页

作者： Aljoumani, Basem Sanchez-Espigares, Jose A. Canameras, Nuria Josa, Ramon Monserrat, Joaquim UPC Dept Agri Food Engn & Biotechnol Castelldefels 08860 Spain UPC Dept Stat & Operat Res Barcelona 08034 Spain Univ Lleida Dept Agroforestry Engn Lleida 25198 Spain

Understanding the field soil water regime is fundamental in scheduling irrigation as well as for monitoring water flow and solute transport. This study was carried out on variable interval irrigation and used time series analysis techniques to predict the soil water content at the interested depth by measuring one single depth in order to precisely determine the next irrigation time and its effect on soil water content at the interested depth. Volumetric water content of silty loam soil in Barcelona was measured in situ with capacitance soil moisture sensors at five depths within the root zone for a horticultural crop during its life cycle in 2010. The time series consisted of hourly measurements of soil water content and was transformed to a stationary situation. Subsequently, the transformed data were used to conduct analyses in the time domain in order to obtain the parameters of a seasonal autoregressive integrated moving average (ARIMA) model. In the case of variable interval irrigation, predicting the soil water content time series cannot be properly explained by the ARIMA model and its underlying normality assumption. By completing the ARIMA model with intervention analysis and outlier detection, the prediction of soil water content in variable interval irrigation can be made. The transfer function models were then used to predict water contents at depths of interest (0.20, 0.35, 0.50 and 0.60 m depths) as well as the average water content W-AVG in the top 0.60 m soil profile by measuring water content at 0.10 m depth. As a result, the predictions were logical. Also, the next irrigation time and its effect on soil water content at the depth of interest were correctly estimated. To confirm results of the models, the experiment was repeated in 2011, and the predicted and observed values agree reasonably well. (C) 2012 Elsevier B.V. All rights reserved.

关键词： Soil volumetric water content Autoregressive integrated moving average (ARIMA) Outlier detection transfer function model

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Control of Voltage in Proton Exchange Membrane Fuel Cell Using model Reference Control Approach

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INTERNATIONAL JOURNAL OF ELECTROCHEMICAL SCIENCE 2012年第8期7卷 6752-6761页

作者： Najafizadegan, Hamideh Zarabadipour, Hassan Imam Khomeini Int Univ Dept Elect Engn Qazvin Iran

The Proton Exchange Membrane Fuel Cell (PEMFC) is one of the most important power supplies. Maintaining a constant voltage in PEM fuel cells has always attracted the attention of many researchers and many articles have been published on this issue. This paper presents a transfer function model of a PEM fuel cell. Subsequently, model Reference Control (MRC) strategy is proposed to fix fuel cell voltage in presence of noise and disturbance. The model and the controller are implemented in the MATLAB and SIMULINK environment and results are compared with a PID controller.

关键词： model Reference Control PEM Fuel Cell transfer function model

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What role will hubs play in the LCC point-to-point connections era? The Spanish experience

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JOURNAL OF TRANSPORT GEOGRAPHY 2012年 24卷 262-270页

作者： Castillo-Manzano, Jose I. Lopez-Valpuesta, Lourdes Pedregal, Diego J. Univ Seville Fac Ciencias Econ & Empresariales Seville 41018 Spain Univ Castilla La Mancha Escuela Tecn Super Ingenieros Ind E-13071 Ciudad Real Spain

Airport systems organized spatially as hub-and-spoke systems where traditional airlines (Full-Service Network Carriers - FSNCs) dominate have been impacted by the continuing expansion of Low-Cost Carriers (LCCs) in mainly point-to-point connection systems. Using a methodology based on linear transfer function models, the objective of this paper is to reflect on the future of hubs and on whether their role as large geographical air transport nodes is in doubt. Although Spanish hubs have continued to strengthen their position of dominance, the consequences of this enforced coexistence has manifested itself in a substitution effect, with LCCs replacing FSNCs at the hubs for international, primarily intra-European, flights. The market for national flights, however, has not experienced any significant changes as this new development of LCCs in this market is fundamentally based on new demand from both new passengers and the greater travel frequency of current passengers. There is also room for complementarity between the two models, as national connections with LCC hubs feed long-distance destinations exploited solely by the FSNCs. (C) 2012 Elsevier Ltd. All rights reserved.

关键词： Hub-and-spoke system Point-to-point system Low-cost carriers transfer function model Substitution effects

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A New Method of Determining the Pile-Soil Parameters

A New Method of Determining the Pile-Soil Parameters

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4th International Conference on Technology of Architecture and Structure (ICTAS 2011)

作者： Cui, Guangqin Liu, Zengrong Ma, Chenguang Xian Univ Architecture & Technol Xian 710055 Shanxi Peoples R China Northwest Res Inst Engn Investigat & Design Xian 710003 Peoples R China

ISBN: (纸本)9783037852781

Basic transfer differential equation and transferring model of load transfer method were given at first, and the pile-soil loading state was divided into five stages according to the increasing pile-head loading process. Next, based on the overall equilibrium of pile and boundary conditions, analytical stiffness expressions of single pile relating to these transferring model parameters were derived in stages. And then, the field static load test result, Q-s curve, was also divided into five corresponding stages and subsection fitting was suggested to be made for each stage. Finally, each model parameter was determined one by one in stages according to the corresponding relations between the measured Q-s curve and the proposed analytical solutions. This pile-soil parameters determination method would enhance the application value of the measured Q-s curve in some extent, and it would provide a theoretical basis for further study on mechanical properties of pile-soil system.

关键词： transfer function model single pile stiffness Q-s curve parameters identification

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Investigating alien plant invasion in urban riparian forests in a hot and semi-arid region

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LANDSCAPE AND URBAN PLANNING 2011年第3期100卷 278-286页

作者： Sung, Chan Yong Li, Ming-Han Rogers, George O. Volder, Astrid Wang, Zhifang Texas A&M Univ Texas Transportat Inst College Stn TX 78743 USA Texas A&M Univ Dept Landscape Architecture & Urban Planning College Stn TX 78743 USA Texas A&M Univ Dept Hort Sci College Stn TX 78743 USA

In this paper, we examined twelve riparian forests along urban-rural gradients in Austin, TX (USA), on the relationship among watershed urbanization and the invasion of alien woody species. We assessed the degree of biological invasion by measuring relative alien cover (RAC) of the riparian forests. We also measured environmental variables (15 in total) that characterize the study forests, including impervious surface percentage of corresponding watersheds, stream hydrology of adjacent streams, species diversity, canopy gap percentage, and soil nutrient contents of the riparian forests. Stream hydrology was quantified by the transfer function model. The results indicate that impervious surface percentage was related to stream hydrology: the more the impervious surface in a watershed, the faster streamflow recedes after the storm, and the longer dry period the riparian forest experienced (R-2 = 0.722). Impervious surface percentage was also related to RAC (R-2 = 0.498). Nonmetric multidimensional scaling (NMDS) grouped the 15 environmental variables into five dimensions. Multiple regression analysis of RAC on the five NMDS dimensions shows that RAC was related only to the dimension related to hydrological drought. Based on these results, we concluded that watershed urbanization facilitates the invasion of alien species in riparian forests by causing hydrologic drought, particularly in hot and semi-arid regions. Published by Elsevier B.V.

关键词： transfer function model Nonmetric multidimensional scaling Ecosystem disturbance Drought Urban watershed management Ecosystem resistance

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On embedded FIR filter models for identifying continuous-time and discrete-time transfer functions: the RPM approach

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INTERNATIONAL JOURNAL OF CONTROL 2011年第3期84卷 616-632页

作者： Ouvrard, Regis Trigeassou, Jean-Claude Univ Poitiers F-86022 Poitiers France Univ Bordeaux F-33405 Talence France

For identifying a continuous-time (CT) transfer function model, data filtering is a solution which provides the necessary unmeasurable input-output derivative approximations. In discrete-time (DT) system identification, the well-known ARX model can be used successfully if the estimate is performed with suitable prefiltered data. This article describes the reinitialised partial moment (RPM) model which embeds implicitly a finite impulse response filter in both CT and DT domains. With knowledge of the important role of data prefiltering in standard methods, this RPM model embedded filter gives particular properties to this original tool. Although both the CT RPM model and the DT RPM model present an embedded filter, the formulation and the implementation in the CT and the DT domains are different. Therefore, the aim of this article is to present a tutorial on the RPM models and to give an overview of all the applications.

关键词： continuous-time model discrete-time model reinitialised partial moments RPM filter RPM model system identification transfer function model

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transfer and backtransfer processes in Yb³⁺-Er³⁺ codoped Strontium Barium Niobate glass-ceramics

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JOURNAL OF LUMINESCENCE 2011年第12期131卷 2446-2450页

作者： Martin, L. L. Martin, I. R. Haro-Gonzalez, P. Univ La Laguna Fac Fis Dept Fis Fundamental & Expt Elect & Sistemas E-38206 San Cristobal la Laguna S C De Tenerife Spain

The forward and backward energy transfer processes in Strontium Barium Niobate glass-ceramics double doped with Yb3+ and Er3+ ions have been studied. In these samples the rare earth ions are incorporated into the nanocrystals with an average size of 50 nm. Using laser excitation at 950 nm is possible to excite selectively the Yb3+ ions and detect emission due to these ions (at 1040 nm) or combined with the Er3+ ions (at 980 nm). In previous works, the energy transfer processes between these ions in different matrices have been analyzed in order to improve the emission at 1550 nm, but these analyses are restricted to fast migration processes among ions. In this fast migration regimen the results are valid only for larger concentrations. However, in this work the dynamics of these transfer processes has been carried out using a general method called "transfer function model". The parameters which characterize these processes have been obtained and it has been possible to explain the important increase of the emission at 1550 nm due to the co-doping with Yb3+ ions. This analysis is valid for any range of doping concentrations. (C) 2011 Elsevier B.V. All rights reserved.

关键词： Strontium Barium Niobate transfer function model transfer backtransfer

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