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arXiv 2023年

作者： Miller, Jared Tacchi, Matteo Sznaier, Mario Jasour, Ashkan ETH Zürich Physikstrasse 3 Zürich8092 Switzerland Automatic Control Laboratory EPFL Lausanne1015 Switzerland Univ. Grenoble Alpes CNRS Grenoble INP Institute of Engineering GIPSA-lab Grenoble38000 France The Robust Systems Lab ECE Department Northeastern University BostonMA02115 United States The Team 347T-Robotic Aerial Mobility Jet Propulsion Lab PasadenaCA91109 United States

This paper formulates algorithms to upper-bound the maximum Value-at-Risk (VaR) of a state function along trajectories of stochastic processes. The VaR is upper bounded by two methods: minimax tail-bounds (Cantelli/Vysochanskij-Petunin) and Expected Shortfall/Conditional Value-at-Risk (ES). Tail-bounds lead to a infinite-dimensional Second Order Cone Program (SOCP) in occupation measures, while the ES approach creates a Linear Program (LP) in occupation measures. Under compactness and regularity conditions, there is no relaxation gap between the infinite-dimensional convex programs and their nonconvex optimal-stopping stochastic problems. Upper-bounds on the SOCP and LP are obtained by a sequence of semidefinite programs through the moment-Sum-of-Squares hierarchy. The VaR-upper-bounds are demonstrated on example continuous-time and discrete-time polynomial stochastic processes. Copyright © 2023, The Authors. All rights reserved.

关键词： Random processes

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Economic model predictive control for obstacle-aided snake robot locomotion

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IFAC-PapersOnLine 2020年第2期53卷 9702-9708页

作者： Evan Müller Philipp N. Köhler Kristin Y. Pettersen Frank Allgöwer Institute for Systems Theory and Automatic Control University of Stuttgart Stuttgart Germany. Center for Autonomous Marine Operations and Systems Department of Engineering Cybernetics Norwegian University of Science and Technology Trondheim Norway.

This paper studies the application of economic model predictive control (MPC) to snake robot locomotion. The proposed MPC algorithm integrates the gait pattern creation into the closed loop by maximizing the forward snake velocity. We consider both purely planar locomotion as well as obstacle-aided locomotion. A compliant obstacle-snake contact model is introduced, rendering the interaction dynamics considered in the optimal control problem smooth. We illustrate the efficacy of the scheme by numerical simulations. The emerging gait patterns are undulatory and can make simultaneous use of anisotropic ground friction and obstacles.

关键词： Model Predictive control Mobile robots Obstacles Trajectory planning

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Distributed control of Second-Order Multi-Agent systems:Fractional Integral Action and Consensus

Distributed Control of Second-Order Multi-Agent Systems:Frac...

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第三十九届中国控制会议

作者： Ricardo Cajo Shiquan Zhao Douglas Plaza Robain De Keyser Clara Ionescu Ghent University Research group on Dynamical Systems and Control Harbin Engineering University College of Automation Technical University of Cluj-Napoca Department of Automatic Control

This article addresses the consensus problem in multi-agent systems modeled with double-integrator dynamics under constant disturbances. Therefore, a fractional control protocol to enhance the convergence speed and robustness of the system is proposed. The communication topology of the system is represented by an undirected connected graph. In addition, the convergence of the system is analyzed with the stability boundary locus method, through which analytical expressions are deduced to ensure the stability of the agents group. Finally, an example is provided to illustrate the validity of the theoretical results.

关键词： Multi-agents Consensus problem Fractional calculus Distributed control Double-integrator dynamics

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controllability analysis and controller design for variable-pitch propeller quadcopters with one propeller failure

Advanced Control for Applications: Engineering and Industria...

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Advanced control for Applications: engineering and Industrial systems 2020年第2期2卷

作者： Wang, Zhikun Groß, Roderich Zhao, Shiyu Department of Automatic Control and Systems Engineering The University of Sheffield United Kingdom School of Engineering Westlake University Afghanistan Institute of Advanced Technology Westlake Institute for Advanced Study Afghanistan

This article studies a relatively new type of aerial platform: variable-pitch propeller (VPP) quadcopters. Unlike conventional fixed-pitch propellers that can only generate upward thrust forces, a VPP can adjust its pitch angle to generate either upward or downward thrust forces. This provides VPP quadcopter with high agility and strong maneuverability. Although VPP quadcopters have attracted some attention recently, their potential has not been fully explored yet. In this article, we study the fault-tolerant property of VPP quadcopters when one of the four VPPs fails to provide any forces or torques. We identify the equilibrium state in this case and conduct the controllability analysis based on a linearized model. This shows that the system remains controllable even if one propeller fails. As a result, simple linear-quadratic regulator controllers can be used to control the platform. Although the controllability analysis and controller are based on the linearized model, numerical simulation incorporating measurement noises and external disturbances verifies the theoretic findings. © 2020 John Wiley & Sons, Ltd.

关键词： controllers

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Inspection Trajectory Planning for 3D Structures under a Mixed-Integer Framework 15

Inspection Trajectory Planning for 3D Structures under a Mix...

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15th IEEE International Conference on control and Automation, ICCA 2019

作者： Stoican, Florin Prodan, Ionela Grøtli, Esten Ingar Nguyen, Ngoc Thinh UPB Department of Automatic Control and Systems Engineering Romania Valence F-26000 France SINTEF Digital Mathematics and Cybernetics Norway

ISBN: (纸本)9781728111643

This paper extends our previous work on constrained trajectory generation for UAVs (Unmanned Aerial Vehicles) with the task of fully covering an a priori known 3D structure. The novelty resides in the geometrical approach we adopt to describe sufficient coverage constraints in a mixed-integer formulation. The combined use of hyperplane arrangement, cell merging procedures and mixed-integer formulations provides feasible 'viewpoint' regions through which the trajectory has to pass. The selected viewpoints with their corresponding feasible cells allow the vehicle to fully cover the 3D structure. The tools used and the results obtained are exemplified over a particular quadcopter system. © 2019 IEEE.

关键词： Trajectories

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Parameter estimation and control of an unmanned aircraft-based transportation system for variable-mass payloads

Parameter estimation and control of an unmanned aircraft-bas...

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作者： Alatorre, Armando Espinoza, Eduardo S. Sánchez, Bonifacio Ordaz, Patricio Muñoz, Filiberto García Carrillo, Luis Rodolfo French-Mexican Laboratory of Informatics and Automatics Center of Research and Advanced Studies of the National Polytechnic Institute México City Mexico Automatic Control Department Center of Research and Advanced Studies of the National Polytechnic Institute México City Mexico Research Center of Information Technologies and Systems Autonomous University of the State of Hidalgo Hidalgo Mexico Klipsch School of Electrical and Computer Engineering New Mexico State University Las CrucesNM United States

This paper deals with the development of an adaptive robust controller for an Unmanned Aircraft System with variable mass. The goal is to improve trajectory tracking and energy performance while the aircraft mass is gradually reducing due to payload release. To improve the trajectory tracking performance, we propose an algorithm that merges the concepts of least squares method and sliding mode observer for the estimation of the vehicle mass. The nonlinear observer estimates the linear velocities and accelerations, which are further used to obtain the vehicle mass. A robust adaptive pole placement controller based on the Attractive Ellipsoid Method uses this estimation to update the controllers gains due to the mass variation. To validate the effectiveness of the proposed algorithm for performing aerial transportation and deployment of payloads, we present a numerical example comparing the performance of the proposed method with respect to using Proportional Derivative controllers as well as Robust controllers. © 2021 Chinese automatic control Society and John Wiley & Sons Australia, Ltd

关键词： controllers

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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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Distributed model predictive control of buildings and energy hubs

arXiv

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arXiv 2021年

作者： Lefebure, Nicolas Khosravi, Mohammad De Badyn, Mathias Hudoba Bünning, Felix Lygeros, John Jones, Colin Smith, Roy S. Department of Mechanical Engineering Swiss Federal Institute of Technology Lausanne Switzerland Automatic Control Laboratory Swiss Federal Institute of Technology Zürich Switzerland Empa Urban Energy Systems Laboratory Überlandstrasse 129 Dübendorf8600 Switzerland

Model predictive control (MPC) strategies can be applied to the coordination of energy hubs to reduce their energy consumption. Despite the effectiveness of these techniques, their potential for energy savings are potentially underutilized due to the fact that energy demands are often assumed to be fixed quantities rather than controlled dynamic variables. The joint optimization of energy hubs and buildings' energy management systems can result in higher energy savings. This paper investigates how different MPC strategies perform on energy management systems in buildings and energy hubs. We first discuss two MPC approaches;centralized and decentralized. While the centralized control strategy offers optimal performance, its implementation is computationally prohibitive and raises privacy concerns. On the other hand, the decentralized control approach, which offers ease of implementation, displays significantly lower performance. We propose a third strategy, distributed control based on dual decomposition, which has the advantages of both approaches. Numerical case studies and comparisons demonstrate that the performance of distributed control is close to the performance of the centralized case, while maintaining a significantly lower computational burden, especially in large-scale scenarios with many agents. Finally, we validate and verify the reliability of the proposed method through an experiment on a full-scale energy hub system in the NEST demonstrator in Dübendorf, Switzerland. Copyright © 2021, The Authors. All rights reserved.

关键词： Predictive control systems

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Modeling the effects of a lightbridge on oscillations in a solar pore

arXiv

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arXiv 2024年

作者： Schiavo, Luiz A.C.A. Gordovskyy, Mykola Browning, Philippa Silva, Suzana S.A. Verth, Gary Ballai, Istvan Shelyag, Sergiy Ruzheinikov, Sergey N. McLaughlin, James A. Fedun, Viktor Department of Mathematics Physics and Electrical Engineering Northumbria University NewcastleNE1 8ST United Kingdom Centre for Astrophysics Research Department of Physics Astronomy & Mathematics University of Hertfordshire HatfieldAL10 9AB United Kingdom Jodrell Bank Centre for Astrophysics University of Manchester ManchesterM13 9PL United Kingdom Plasma Dynamics Group Department of Automatic Control and Systems Engineering The University of Sheffield Mappin Street SheffieldS1 3JD United Kingdom Plasma Dynamics Group School of Mathematics and Statistics University of Sheffield Hounsfield Road SheffieldS3 7RH United Kingdom College of Science and Engineering Flinders University TonsleySA5042 Australia

Solar pores are ideal magnetic structures for wave propagation and transport of energy radially-outwards across the upper layers of the solar atmosphere. We aim to model the excitation and propagation of magnetohydrodynamic waves in a pore with a lightbridge modelled as two interacting magnetic flux tubes separated by a thin, weaker field, layer. We solve the three-dimensional MHD equations numerically and calculate the circulation as a measure of net torsional motion. We find that the interaction between flux tubes results in the natural excitation of propagating torsional Alfvén waves, but find no torsional waves in the model with a single flux tube. The torsional Alfvén waves propagate with wave speeds matching the local Alfvén speed where wave amplitude peaks. Copyright © 2024, The Authors. All rights reserved.

关键词： Plasma magnetohydrodynamic waves

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