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Adaptive stabilization of minimum-phase systems under quantized measurements

IFAC-PapersOnLine 2020年第2期53卷 3761-3766页

作者： Anton Selivanov Alexander Fradkov Department of Automatic Control and Systems Engineering The University of Sheffield UK Saint Petersburg University Russia Institute for Problems of Mechanical Engineering Russian Academy of Sciences Russia

We construct an adaptive controller for a linear minimum-phase system of an arbitrary relative degree with an unknown bounded disturbance and dynamically quantized measurements. The key novelty is the extension of the shunting method (parallel feedforward compensator) to plants with bounded disturbances. This method leads to an augmented system of relative degree one that is stabilized by a passification-based adaptive controller. Moreover, we design a switching procedure for the controller parameters and the quantizer’s zoom that ensures the state convergence from an arbitrary set to an ellipsoid whose size depends on the disturbance bound. The results are demonstrated by an example of an aircraft flight control.

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A Converse Sum of Squares Lyapunov Function for Outer Approximation of Minimal Attractor Sets of Nonlinear systems

arXiv

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arXiv 2021年

作者： Jones, Morgan Peet, Matthew M. The Department of Automatic Control and Systems Engineering The University of Sheffield Amy Johnson Building Mappin Street SheffieldS1 3JD United Kingdom The School for the Engineering of Matter Transport and Energy Arizona State University TempeAZ85298 United States

Many dynamical systems described by nonlinear ODEs are unstable. Their associated solutions do not converge towards an equilibrium point, but rather converge towards some invariant subset of the state space called an attractor set. For a given ODE, in general, the existence, shape and structure of the attractor sets of the ODE are unknown. Fortunately, the sublevel sets of Lyapunov functions can provide bounds on the attractor sets of ODEs. In this paper we propose a new Lyapunov characterization of attractor sets that is well suited to the problem of finding the minimal attractor set. We show our Lyapunov characterization is non-conservative even when restricted to Sum-of-Squares (SOS) Lyapunov functions. Given these results, we propose a SOS programming problem based on determinant maximization that yields an SOS Lyapunov function whose 1-sublevel set has minimal volume, is an attractor set itself, and provides an optimal outer approximation of the minimal attractor set of the ODE. Several numerical examples are presented including the Lorenz attractor and Van-der-Pol oscillator. Copyright © 2021, The Authors. All rights reserved.

关键词： Lyapunov functions

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A temporal-to-spatial deep convolutional neural network for classification of hand movements from multichannel electromyography data

arXiv

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arXiv 2020年

作者： Hartwell, Adam Kadirkamanathan, Viskan Anderson, Sean R. Department of Automatic Control and Systems Engineering University of Sheffield SheffieldS1 3JD United Kingdom

Deep convolutional neural networks (CNNs) are appealing for the purpose of classification of hand movements from surface electromyography (sEMG) data because they have the ability to perform automated person-specific feature extraction from raw data. In this paper, we make the novel contribution of proposing and evaluating a design for the early processing layers in the deep CNN for multichannel sEMG. Specifically, we propose a novel temporal-to-spatial (TtS) CNN architecture, where the first layer performs convolution separately on each sEMG channel to extract temporal features. This is motivated by the idea that sEMG signals in each channel are mediated by one or a small subset of muscles, whose temporal activation patterns are associated with the signature features of a gesture. The temporal layer captures these signature features for each channel separately, which are then spatially mixed in successive layers to recognise a specific gesture. A practical advantage is that this approach also makes the CNN simple to design for different sample rates. We use NinaPro database 1 (27 subjects and 52 movements + rest), sampled at 100 Hz, and database 2 (40 subjects and 40 movements + rest), sampled at 2 kHz, to evaluate our proposed CNN design. We benchmark against a feature-based support vector machine (SVM) classifier, two CNNs from the literature, and an additional standard design of CNN. We find that our novel TtS CNN design achieves 66.6% per-class accuracy on database 1, and 67.8% on database 2, and that the TtS CNN outperforms all other compared classifiers using a statistical hypothesis test at the 2% significance level. Copyright © 2020, The Authors. All rights reserved.

关键词： Deep neural networks

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NARMAX model as a sparse, interpretable and transparent machine learning approach for big medical and healthcare data analysis 21

NARMAX model as a sparse, interpretable and transparent mach...

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21st IEEE International Conference on High Performance Computing and Communications, 17th IEEE International Conference on Smart City and 5th IEEE International Conference on Data Science and systems, HPCC/SmartCity/DSS 2019

作者： Billings, Stephen Wei, Hua-Liang Department of Automatic Control and Systems Engineering United Kingdom INSIGNEO Institute for in Silico Medicine University of Sheffield Sheffield United Kingdom

ISBN: (纸本)9781728120584

Influenza and influenza-like illnesses are one of the leading causes of death in the world, resulting in heavy losses to individual families and nations. Accurate and timely forecasts of seasonal influenza would therefore crucially important to inform and facilitate public health decision-making for presenting and intervening influenza epidemics. System identification and data-driven modelling approaches play an indispensable role in analyzing and understanding complex processes including medical, healthcare and environmental time series. This paper aims to present a type of sparse, interpretable and transparent (SIT) model, which cannot only be used for future behavior prediction but more importantly for understanding the dependent relationship between the response variables of a system on potential independent variables (also known as input variables or predictors). An ideal candidate for such a SIT representation is the well-known NARMAX (nonlinear autoregressive moving average with exogenous inputs) model, which can be established based on input and output data of the system of interest, and the final refined model is usually simple, parsimonious and easy to interpret. The general framework of the NARMAX model is presented, and the state-of-the-art algorithms for such a SIT model estimation are described. Two case studies are provided to illustrate how well the SIT-NARMAX model can work for medical, healthcare and related data. © 2019 IEEE.

关键词： Forecasting

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Switched PI control Based MRAS for Sensorless control of PMSM Drives Using Fuzzy-Logic-controller

Research Square

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Research Square 2021年

作者： Liu, Zhao-Hua Nie, Jie Wei, Hua-Liang Wu, Fa-Ming Chen, Lei Zhang, Zhu School of Information and Electrical Engineering Hunan University of Science and Technology Xiangtan411201 China Department of Automatic Control and Systems Engineering University of Sheffield SheffieldS1 3JD United Kingdom CRRC Zhuzhou Institute Company Ltd Zhuzhou412007 China

With the use of sensorless control mechanical position sensors can be removed from the gearbox, so as to decrease the maintenance costs and enhance the system robustness. In this paper, switched PI control based model reference adaptive system (MRAS) observer using Fuzzy-Logic-controller (FLC) is introduced for sensorless control of permanent magnet synchronous motor (PMSM) drives. The main work and innovation of this paper include: 1) An FLC is designed for speed and current control. The response performance of speed regulation and the accuracy of the command voltage are improved and the difficulty of manual adjustment of control parameters is avoided. In addition, the disturbance observer is established to compensate the nonlinear effect caused by voltage source inverter (VSI). Therefore, the robustness of PMSM vector control system is improved and the sensorless control precision is guaranteed. 2) A sensorless control strategy of a switched PI control based MRAS observer is proposed for stator resistance tracking, which can improve the accuracy of resistance estimation and improve the dynamic performance of sensorless control. 3) The experimental results are given to verify the availability of the proposed scheme. © 2021, CC BY.

关键词： Sensorless control

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Historical Overview of the Passification Method and its Applications to Nonlinear and Adaptive control Problems

Historical Overview of the Passification Method and its Appl...

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European control Conference (ECC)

作者： Boris Andrievsky Anton Selivanov Institute for Problems of Mechanical Engineering of RAS Saint Petersburg Department of Automatic Control and Systems Engineering The University of Sheffield UK

The present survey paper provides a historical overview of the method of passification and its applications to nonlinear and adaptive control problems from 1980 to present days.

ISBN: (数字)9783907144022

ISBN: (纸本)9781728188133

The present survey paper provides a historical overview of the method of passification and its applications to nonlinear and adaptive control problems from 1980 to present days.

关键词： Adaptive control Synchronization Robustness Nonlinear systems Circuit stability control systems

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A Data Driven Condition Monitoring of Chain Type Structures by Using Nonlinear Frequency Analyses 2

A Data Driven Condition Monitoring of Chain Type Structures ...

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2nd International Conference on Industrial Artificial Intelligence, IAI 2020

作者： Gao, Yi Luo, Zhong Zhu, Yunpeng Qiu, Yue Li, Yuqi Key Laboratory of Vibration and Control of Aero-Propulsion Systems Ministry of Education of China Northeastern University Shenyang110819 China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian116024 China University of Sheffield Department of Automatic Control and System Engineering SheffieldS13JD United Kingdom

ISBN: (纸本)9781728182162

A novel data driven condition monitoring approach is proposed in this study to detect the location of nonlinear faults in chain type structures. In this approach, the chain type system is characterized by representing the relationships between any two adjacent measurement points by NARX (Nonlinear Auto-Regressive with Exogenous Inputs) model. A new indicator for condition monitoring, known as the NET (Nonlinear Energy Transmission) indicator, is introduced based on the evaluation of the NRSFs (Nonlinear Response Spectrum Functions) of the chain type system. A 3 DOF system is employed to demonstrate the application of the data driven condition monitoring by using the NET indicator. A case study on the condition monitoring of a rotor-bearing system is then discussed to validate the advantage of the proposed approach in engineering practice. © 2020 IEEE.

关键词： Condition monitoring

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Dynamic Traffic Reconstruction using Probe Vehicles

arXiv

引用

arXiv 2020年

作者： Barreau, Matthieu Selivanov, Anton Johansson, Karl Henrik Division of Decision and Control Systems KTH Royal Institute of Technology Stockholm Sweden Department of Automatic Control and Systems Engineering University of Sheffield United Kingdom

This article deals with the observation problem in traffic flow theory. The model used is the semilinear viscous Burgers equation. Instead of using the traditional fixed sensors to estimate the state of the traffic at given points, the measurements here are obtained from Probe Vehicles (PVs). We propose then a moving dynamic boundary observer whose boundaries are defined by the trajectories of the PVs. The main result of this article is the exponential convergence of the observation error, and, in some cases, its finite-time convergence. Finally, numerical simulations show that it is possible to observe the traffic in the congested, free-flow, and mixed regimes provided that the number of PVs is large enough. Copyright © 2020, The Authors. All rights reserved.

关键词： Probes

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Guidance on the use of complex systems models for economic evaluations of public health interventions

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HEALTH ECONOMICS 2023年第7期32卷 1603-1625页

作者： Breeze, Penny R. Squires, Hazel Ennis, Kate Meier, Petra Hayes, Kate Lomax, Nik Shiell, Alan Kee, Frank de Vocht, Frank O'Flaherty, Martin Gilbert, Nigel Purshouse, Robin Robinson, Stewart Dodd, Peter J. Strong, Mark Paisley, Suzy Smith, Richard Briggs, Andrew Shahab, Lion Occhipinti, Jo-An Lawson, Kenny Bayley, Thomas Smith, Robert Boyd, Jennifer Kadirkamanathan, Visakan Cookson, Richard Hernandez-Alava, Monica Jackson, Christopher H. Karapici, Amanda Sassi, Franco Scarborough, Peter Siebert, Uwe Silverman, Eric Vale, Luke Walsh, Cathal Brennan, Alan School of Health and Related Research University of Sheffield Sheffield UK British Medical Journal Technology Appraisal Group London UK MRC/CSO Social and Public Health Sciences Unit University of Glasgow Scotland UK School of Geography University of Leeds Leeds UK Department of Public Health LaTrobe University Melbourne Australia Centre for Public Health Queen's University Belfast Belfast UK Population Health Sciences Bristol Medical School University of Bristol Bristol UK NIHR Applied Research Collaboration West (ARC West) Bristol UK Department of Public Health Policy and Systems University of Liverpool Liverpool UK CRESS University of Surrey Guildford UK Department of Automatic Control and Systems Engineering University of Sheffield Sheffield UK Business School University of Newcastle Newcastle UK Lumanity-HEOR South Yorkshire Sheffield UK College of Medicine and Health University of Exeter Exeter UK London School of Hygiene & Tropical Medicine London UK Department of Behavioural Science and Health UCL London UK Brain and Mind Centre University of Sydney New South Wales Camperdown Australia United Kingdom Health Security Agency Birmingham UK MRC/CSO Social and Public Health Sciences Unit University of Glasgow Glasgow UK Centre for Health Economics University of York Heslington UK MRC Biostatistics Unit University of Cambridge Cambridge UK NIHR SPHR London School of Hygiene and Tropical Medicine London UK Centre for Health Economics & Policy Innovation Imperial College Business School London UK Nuffield Department of Population Health University of Oxford Oxfordshire Oxford UK Department of Public Health Health Services Research and Health Technology Assessment UMIT TIROL - University for Health Sciences and Technology Hall in Tirol Tyrol Austria Division of Health Technology Assessment and Bioinformatics ONCOTYROL - Center for Personalized Cancer Medicine Innsbruck Austria Center for Health Decision Science Departments of Epidemio

To help health economic modelers respond to demands for greater use of complex systems models in public health. To propose identifiable features of such models and support researchers to plan public health modeling projects using these models. A working group of experts in complex systems modeling and economic evaluation was brought together to develop and jointly write guidance for the use of complex systems models for health economic analysis. The content of workshops was informed by a scoping review. A public health complex systems model for economic evaluation is defined as a quantitative, dynamic, non-linear model that incorporates feedback and interactions among model elements, in order to capture emergent outcomes and estimate health, economic and potentially other consequences to inform public policies. The guidance covers: when complex systems modeling is needed;principles for designing a complex systems model;and how to choose an appropriate modeling technique. This paper provides a definition to identify and characterize complex systems models for economic evaluations and proposes guidance on key aspects of the process for health economics analysis. This document will support the development of complex systems models, with impact on public health systems policy and decision making.

关键词： complex systems economic modeling public health

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Aircraft protection for complex threat platforms through integrated EWOS application 18

Aircraft protection for complex threat platforms through int...

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18th International Conference on Aerospace Sciences and Aviation Technology, ASAT 2019

作者： Rudd-Orthner, R. Mihaylova, L.S. Department of Automatic Control and Systems Engineering University of Sheffield Mappin Street SheffieldS1 3JD United Kingdom

The advancement of threats is focusing commanders to consider how to combat these complex threats throughout the kill chain including prior to launch and Anti-Access Area Denial (A2AD). To match this technology race, modern platforms have been designed with integrated command and control systems and automated Defensive Aids Suites built on modular open system architectures incorporating less diverse but more complex software driven systems. The successful operation of these combat systems is reliant upon the availability of accurate, configured, harmonised and "time sensitive" mission data without which the systems may be ineffective. This paper explores the use of threat analysis diagramming techniques, and open architectures tightly integrated with a EWOS life-cycle;to develop countermeasures with a measured response beyond the traditional self-protection kill chain stages of self-protection. It introduces how threat analysis prepares understanding for simulation and how a countermeasure description language can be used to store and exchange countermeasures in a structured form. This level of intelligence data support and analysis coordinated and synchronised across multiple platforms thereby facilitating the complexities of force protection higher up the kill chain into an onion of protection mapped to a Venn diagram of countermeasure types (design intentions) with differing data needs. © 2019 Published under licence by IOP Publishing Ltd.

关键词： Life cycle

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