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20th World Congress of the International-Federation-of-Automatic-Control (IFAC)

作者： Hofreiter, M. Czech Tech Univ Fac Mech Engn Dept Instrumentat & Control Engn Prague Czech Republic

The paper describes a new technique for estimation up to three points on a process frequency response from a single biased-relay feedback test without using the FFT algorithm. The new technique called "shifting method" extends possibilities of the relay feedback identification of dynamic systems describable by linear models. The introduced identification method is applicable for systems with dead time if there are stable limit cycles in biased-relay feedback tests. This approach enables to fit up to five parameters of a process transfer function from data observed by one relay experiment. The method may be used for parameter estimation of linear mathematical models with various structures and therefore it can be used for parameter fitting both isochronic and anisochronic linear models. This is demonstrated on proportional and integrating time delay processes described by isochronic or anisochronic linear models. The paper also introduces explicit formulas for the parameter estimation of the process model of the second order plus time delay. The applicability of the proposed method is demonstrated on simulated examples. Matlab/Simulink programming environment was used for all simulations. (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

关键词： Relay control estimation parameters identification algorithm process model frequency response oscillation

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estimation of mixed soil water content by impedance inversion of GPR data 15

Estimation of mixed soil water content by impedance inversio...

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15th International Conference on Ground Penetrating Radar (GPR)

作者： Li, Jing Zeng, Zhaofa Chen, Lingna Liu, Fengshan Jilin Univ Coll Geoexplorat Sci & Tech Changchun 130026 Jilin Peoples R China Delaware State Univ AMRC Dover DE 19901 USA

ISBN: (纸本)9781479967896

In the vadose zone, soil has become an object of research due to its importance for environmental issues. Description and estimation of the mixed soil water content or dielectric parameter is the essential condition and the key to improving soil investigation with GPR detection. In this paper, first of all, a way to describe 3D random media which the preferred orientation of the multi-scale inhomogeneity is proposed and the importance of reducing the numerical errors with tapering function is stated. Then, we apply the FDTD method to simulate the GPR signal response of random model and use S-transform to test the simulation accuracy. For the complex random soil media, conventional method likes transmission wave method provide model parameter estimation of limited resolution only. Here, we apply a novel reflection amplitude inversion workflow for GPR data which is capable of resolving the subsurface dielectric permittivity and related water content distribution with markedly improved resolution. The synthetic results demonstrate that this method has extensive applicability in complex mixed random soil media detection and physics parameters estimation.

关键词： GPR Impedance inversion Random media model estimation parameters

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Identification of Fractional Linear Dynamical Systems with Autocorrelated Errors in Variables by Generalized Instrumental Variables

Identification of Fractional Linear Dynamical Systems with A...

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17th IFAC Technical-Committee-on-Optimal-Control (TC 2.4) Workshop on Control Applications of Optimization (CAO)

作者： Ivanov, Dmitriy V. Sandler, Ilya L. Kozlov, Evgeniy V. Samara State Univ Transport Samara Russia

This paper addresses the problem of identifying stochastic linear fractional discrete-time systems from noisy input/output data. The input noise is supposed to be fractional noise, while the output noise is assumed colored or fractional noise. The paper also proposes an estimator based on the generalized instrumental variables estimator. We have compared the proposed estimator with other estimators with the help of Monte Carlo simulations. The results of the simulated examples indicate that the proposed estimator provides good accuracy. (C) 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

关键词： Identification estimation parameters errors in variables fractional calculus instrumental variables bias compensation, discrete systems autocorrelated noises fractional noise

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Modified Model-Free Adaptive Control using Compact-Form Dynamic Linearization Technique 21st

Modified Model-Free Adaptive Control using Compact-Form Dyna...

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21st IFAC World Congress on Automatic Control - Meeting Societal Challenges

作者： Hoang Anh Pham Soeffker, Dirk Univ Duisburg Essen Chair Dynam & Control Duisburg Germany

Model-free adaptive control has been used to design feedback in cases when accurate mathematical modeling of the system can not be realized. By using only input-output information, the control approach is attractive with respect to minimal design efforts. In this contribution an improved model-free control program is proposed and applied to flexible systems. The main control idea is based on the compact-form dynamic linearization technique. A linearized controller structure which contains a matrix of unknown time-varying parameters namely pseudo-partial derivative can be designed. First, an equivalent linearized data-based model of the original system is established and corrected locally by using the recursive least-squares estimation algorithm. Then a modified objective function with respect to the controller parameter matrix considering minimization of the current tracking errors and its variations is proposed for control performance improvement. Finally, the required control inputs are calculated to fulfill control requirements. For illustration and as example, the newly introduced method is applied to reduce vibrations of an elastic crane representing a multivariable system. The control effectiveness is verified nummerically and compared with conventional model-free and PI controllers. Copyright (C) 2020 The Authors.

关键词： Model-free adaptive control Dynamic linearization Recursive least-squares estimation parameters Vibration control

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Enabling AUV Mapping of Free-Drifting Icebergs Without External Navigation Aids

Enabling AUV Mapping of Free-Drifting Icebergs Without Exter...

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Oceans Conference

作者： Hammond, Marcus Rock, Stephen M. Stanford Univ Stanford CA 94305 USA MBARI Moss Landing CA 95039 USA

ISBN: (纸本)9781479949182

This paper documents improvements in the method for offline estimation of iceberg geometry as presented by Kimball and Rock [1]. The method removes the AUV's inertial position from the equations, allowing the mission to be completed without ship-based navigation aids. This is a substantial operational advantage. Additionally, it differs from [1] in that it treats each sonar return individually, instead of abstracting multiple readings to a single point, removing a potential source of bias. Finally it reformulates the problem to simplify greatly the estimation optimization by reducing the number of needed estimation parameters. Together, these changes yield speed increases of roughly three orders of magnitude, with no loss in accuracy. The method is demonstrated via full simulation of an AUV operating around a free drifting iceberg. Additionally, an underwater sea cliff in Monterey Canyon is used as an iceberg surrogate to test the method on field data.

关键词： autonomous underwater vehicles oceanographic regions oceanographic techniques optimisation sea ice AUV inertial position AUV mapping Monterey Canyon estimation optimization estimation parameters external navigation aids field data free drifting iceberg free-drifting icebergs iceberg geometry offline estimation operational advantage potential bias source ship-based navigation aids underwater sea cliff Equations estimation Mathematical model Optimization Sonar navigation Vectors Vehicles

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PEMFC state and parameter estimation through a high-gain based adaptive observer 21st

PEMFC state and parameter estimation through a high-gain bas...

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21st IFAC World Congress on Automatic Control - Meeting Societal Challenges

作者： Cecilia, Andreu Serra, Maria Costa-Castello, Ramon CSIC UPC Inst Robot & Informat Ind Llorens & Artigas 4-6 Barcelona 08028 Spain

This work presents the design of an adaptive observer to estimate the cathode catalytic layer's water content of a polymer electrolyte membrane fuel cell and some of the parameters related to its water dynamics. However, in general, existing adaptive observer algorithms require a certain relative degree condition which is not satisfied in the concerned fuel cell system. This conflict is solved by modifying the adaptive observer strategy with an auxiliary signal that does satisfy the relative degree condition. This signal is estimated through a high-gain observer. The viability of the presented observer is validated through numerical simulations. Copyright (C) 2020 The Authors.

关键词： Observers estimation parameters High-gain observer Fuel cells Nonlinear systems

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Chemical sensor screening of blood samples: Robust analysis via data set reduction 5

Chemical sensor screening of blood samples: Robust analysis ...

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5th IFAC Symposium on Modelling and Control in Biomedical Systems

作者： Yates, JWT Gardner, JW Chappell, MJ Bolt, F Beeby, L Dowson, C Univ Warwick Div Elect & Elect Engn Sch Engn Coventry CV4 7AL W Midlands England

ISBN: (纸本)0080441599

Gas sensor analysis of blood samples is shown to be an effective method to screen for bacterial pathogens. In this work, various strains of Staphylococcus Aureus are cultured in a blood medium. The data are analysed using normalisation techniques, Principal Components Analysis (PCA) and Radial Basis Function (RBF) networks trained using the Support Vector Method (SVM). Good separation of data is reported and a classification rate of 100% was obtained. Copyright (C) 2003 IFAC.

关键词： classification data processing discriminant analysis estimation parameters Gaussian functions mass spectrometry neural networks radial basis function networks

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Model Comparison and Parameter estimation of Polymer Exchange Membrane (PEM) Fuel Cell Based on Nonlinear Least Squares Method

Model Comparison and Parameter Estimation of Polymer Exchang...

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International Aegean Conference on Electrical Machines and Power Electronics (ACEMP) / International Conference on Optimization of Electrical and Electronic Equipment (OPTIM)

作者： Ram, Krishnil R. Naidu, Karteek Kumar, Ravinesh Cirrincione, Maurizio Mohammadi, Ali Univ South Pacific Sch Engn & Phsy Suva Fiji

ISBN: (纸本)9781538676875

The comparison of different single cell PEMFC models and the estimation of model parameters are described in this article. Three different models are selected from literature and reviewed. For each PEMFC model the polarization curves were developed and then compared. Nonlinear Least Squares Method have been implemented to find the parameters of each model. The results show that some of the parameters estimated are in agreement with the experimental and simulation model polarization curves while there are more errors in the estimation of the parameters describing the activation losses.

关键词： Least Square PEMFC Modeling estimation parameters

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Generalized parameter estimation-based observers: Application to power systems and chemical-biological reactors

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AUTOMATICA 2021年 129卷

作者： Ortega, Romeo Bobtsov, Alexey Nikolaev, Nikolay Schiffer, Johannes Dochain, Denis ITAM Dept Acad Sistemas Digitales Mexico City DF Mexico ITMO Univ Dept Control Syst & Robot Kronverkskiy Av 49 St Petersburg 197101 Russia Brandenburg Tech Univ Cottbus Senftenberg Fachgebiet Regelungssyst & Netzleitech Cottbus Germany Univ Catholique Louvain UCL CESAME Ave Georges Lemaitre 4 B-1348 Louvain La Neuve Belgium Innopolis Univ Ctr Technol Robot & Mech Components 1 Univ Skaya Str Innopolis 420500 Innopolis Russia

In this paper we propose a new state observer design technique for nonlinear systems. It consists of an extension of the recently introduced parameter estimation-based observer, which is applicable for systems verifying a particular algebraic constraint. In contrast to the previous observer, the new one avoids the need of implementing an open loop integration that may stymie its practical application. We give two versions of this observer, one that ensures asymptotic convergence and the second one that achieves convergence in finite time. In both cases, the required excitation conditions are strictly weaker than the classical persistent of excitation assumption. It is shown that the proposed technique is applicable to the practically important examples of multimachine power systems and chemical-biological reactors. (C) 2021 Elsevier Ltd. All rights reserved.

关键词： estimation parameters Nonlinear systems Observers Time-invariant systems Power systems

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Evaluation of Various Generalized Pareto Probability Distributions for Flood Frequency Analysis

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WATER 2023年第8期15卷

作者： Anghel, Cristian Gabriel Ilinca, Cornel Tech Univ Civil Engn Bucharest Fac Hydrotech Lacul Tei nr 122 124 Bucharest 020396 Romania

This article analyzes six probability distributions from the Generalized Pareto family, with three, four and five parameters, with the main purpose of identifying other distributions from this family with applicability in flood frequency analysis compared to the distribution already used in the literature from this family such as Generalized Pareto Type II and Wakeby. This analysis is part of a larger and more complex research carried out in the Faculty of Hydrotechnics regarding the elaboration of a norm for flood frequency analysis using the linear moments method. In Romania, the standard method of parameter estimation is the method of ordinary moments, thus the transition from this method to the method of linear moments is desired. All the necessary elements for the distribution use are presented, such as the probability density functions, the complementary cumulative distribution functions, the quantile functions, and the exact and approximate relations for estimating parameters, for both methods of parameter estimation. All these elements are necessary for a proper transition between the two methods, especially since the use of the method of ordinary moments is done by choosing the skewness of the observed data depending on the origin of the maximum flows. A flood frequency analysis case study, using annual maximum and annual exceedance series, was carried out for the Prigor River to numerically present the analyzed distributions. The performance of this distribution is evaluated using a linear moments diagram.

关键词： floods frequency analysis extreme value statistics Pareto Wakeby estimation parameters approximate form method of ordinary moments method of linear moments

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