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Effects of thermo-magneto-electro nonlinearity characteristics on the stability of functionally graded piezoelectric beam

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Applied Mathematics and Mechanics(English Edition) 2020年第2期41卷 313-326页

作者： Haohao BI Bo WANG Zichen DENG Shuodao WANG Department of Applied Mathematics Northwestern Polytechnical UniversityXi’an 710072China Ministry of Industry and Information Technology Key Laboratory of Dynamics and Control of Complex Systems Northwestern Polytechnical UniversityXi’an 710072China Department of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China School of Mechanical and Aerospace Engineering Oklahoma State UniversityOklahoma 74078U.S.A.

Due to the increasing interests in using functionally graded piezoelectric materials(FGPMs) in the design of advanced micro-electro-mechanical systems, it is important to understand the stability behaviors of the FGPM beams. In this study, considering the effects of geometrical nonlinearity, temperature, and electricity in the constitutive relations and the effect of the magnetic field on the FGPM beam, the Euler-Bernoulli beam model is adopted, and the nonlinear governing equation of motion is derived via Hamilton's principle. A perturbation method, which can decompose the deflection into static and dynamic components, is utilized to linearize the nonlinear governing equation. Then,a dynamic stability analysis is carried out, and the approximate analytical solutions for the nonlinear frequency and boundary frequencies of the unstable region are *** examples are performed to verify the present analysis. The effects of the static deflection, the static load factor, the temperature change, and the magnetic field flux on the stability behaviors of the FGPM beam are discussed. From the proposed analytical solutions and numerical results, one can easily and clearly find the effects of various controlled parameters, such as geometric and physical properties of the system, on the mechanical behaviors of structures, and the conclusions are very important and useful for the design of micro-devices.

关键词： functionally graded piezoelectric material(FGPM) geometrical nonlinearity stability analysis

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Induced OWA operators in linear regression

Induced OWA operators in linear regression

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作者： Flores-Sosa, Martha Avilés-Ochoa, Ezequiel Merigó, José M. University Autonomous of Occidente Culiacán Mexico School of Information Systems and Modelling Faculty of Engineering and Information Technology University of Technology Sydney UltimoNSW Australia Department of Management Control and Information Systems School of Economics and Business University of Chile Santiago Chile

The induced ordered weighted average (IOWA) is an aggregation operator that provides a parameterized family of operators between the minimum and the maximum. This work presents a new application that uses the simple linear regression (LR) and the IOWA operator in the same formulation. We study some of its main properties and particular cases. The main advantage of the linear regression IOWA operator is that it unifies the IOWA operator with the linear regression in the same formulation considering the degree of optimism and pessimism of the decision maker. Thus, we can under- or over- estimate the regression according to complex attitudes that the decision may have in the analysis. The work ends analyzing the applicability of this new approach in a problem regarding exchange rate forecasting. The objective of the new approach is to analyze the information in a more complete way. © 2020 - IOS Press and the authors. All rights reserved.

关键词： Linear regression

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SOLPS-ITER simulation of an X-point radiator in TCV

arXiv

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arXiv 2023年

作者： Sun, G. Pan, O. Bernert, M. Carpita, M. Duval, B.P. Février, O. Koenders, J.T.W. Reimerdes, H. Theiler, C. Wiesen, S. Colandrea, C. Gorno, S. Huett, E. Max-Planck-Institut für Plasmaphysik Garching85748 Germany DIFFER-Dutch Institute for Fundamental Energy Research Eindhoven Netherlands Department of Mechanical Engineering Control Systems Technology Group Eindhoven University of Technology Eindhoven Netherlands Forschungszentrum Jülich GmbH Institut für Energie- und Klimaforschung - Plasmaphysik Jülich52425 Germany LausanneCH-1015 Switzerland

SOLPS-ITER simulation is performed to reproduce the X-point radiator recently observed in nitrogen-seeded TCV experiments, which is a scenario that may be favorable to solve the power exhaust problems in future fusion devices. The simulations reveal the transition from the detached regime without XPR to the XPR regime, when increasing the nitrogen seeding rate. A cold X-point core surrounded by ionizing and radiative mentals is formed inside the separatrix and slightly above the X-point, where more than 90% of the total input power is dissipated. The cold X-point core exhibits a temperature of approximately 1eV and features high recombination rate to host the convective fluxes from the ionizing mental. Increasing nitrogen seeding rate also moves the nitrogen ionization front away from the target faster than the nitrogen stagnation point, which enhances the divertor nitrogen leakage to the main chamber and benefits the XPR region cooling. Carbon radiation decreases as the nitrogen seeding increases, and carbon radiation contributes to above 5% of the core impurity radiation before entering the XPR, which decreases to 2.8% when reaching the XPR. Both baffled and unbaffled divertor geometries are simulated and compared, showing that baffles facilitate the access to XPR by increasing the X-point neutral density, but requires higher seeding rate to enter the XPR regime. © 2023, CC BY.

关键词： Fusion reactor divertors

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An Efficient Spatial-Temporal Trajectory Planner for Autonomous Vehicles in Unstructured Environments

arXiv

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arXiv 2022年

作者： Han, Zhichao Wu, Yuwei Li, Tong Zhang, Lu Pei, Liuao Xu, Long Li, Chengyang Ma, Changjia Xu, Chao Shen, Shaojie Gao, Fei State Key Laboratory of Industrial Control Technology Zhejiang University Hangzhou310027 China Huzhou Institute of Zhejiang University Huzhou313000 China Department of Electrical and Systems Engineering University of Pennsylvania PhiladelphiaPA19104 United States Department of Electronic and Computer Engineering Hong Kong University of Science and Technology Hong Kong

As a core part of autonomous driving systems, motion planning has received extensive attention from academia and industry. However, real-time trajectory planning capable of spatial-temporal joint optimization is challenged by nonholonomic dynamics, particularly in the presence of unstructured environments and dynamic obstacles. To bridge the gap, we propose a real-time trajectory optimization method that can generate a high-quality whole-body trajectory under arbitrary environmental constraints. By leveraging the differential flatness property of car-like robots, we simplify the trajectory representation and analytically formulate the planning problem while maintaining the feasibility of the nonholonomic dynamics. Moreover, we achieve efficient obstacle avoidance with a safe driving corridor for unmodelled obstacles and signed distance approximations for dynamic moving objects. We present comprehensive benchmarks with State-of-the-Art methods, demonstrating the significance of the proposed method in terms of efficiency and trajectory quality. Real-world experiments verify the practicality of our algorithm. We will release our codes for the research community.1 Copyright © 2022, The Authors. All rights reserved.

关键词： Autonomous vehicles

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Constraint-adaptive MPC for large-scale systems: Satisfying state constraints without imposing them

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IFAC-PapersOnLine 2021年第6期54卷 232-237页

作者： S.A.N. Nouwens B. de Jager M. Paulides W.P.M.H. Heemels Eindhoven University of Technology Mechanical Engineering - Control Systems Technology Rotterdam The Netherlands Electrical Engineering - Electromagnetics for Care & Cure Lab Rotterdam The Netherlands Eindhoven The Netherlands Erasmus University Medical Center Cancer Institute Department of Radiotherapy Rotterdam The Netherlands

Model Predictive control (MPC) is a successful control methodology, which is applied to increasingly complex systems. However, real-time feasibility of MPC can be challenging for complex systems, certainly when an (extremely) large number of constraints have to be adhered to. For such scenarios with a large number of state constraints, this paper proposes two novel MPC schemes for general nonlinear systems, which we call constraint-adaptive MPC. These novel schemes dynamically select at each time step a (varying) set of constraints that are included in the on-line optimization problem. Carefully selecting the included constraints can significantly reduce, as we will demonstrate, the computational complexity with often only a slight impact on the closed-loop performance. Although not all (state) constraints are imposed in the on-line optimization, the schemes still guarantee recursive feasibility and constraint satisfaction. A numerical case study illustrates the proposed MPC schemes and demonstrates the achieved computation time improvements exceeding two orders of magnitude without loss of performance.

关键词： Model Predictive control Large-Scale systems Adaptive Constraints

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Distributed learning for optimal allocation of synchronous and converter-based generation

arXiv

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arXiv 2020年

作者： Jouini, Taouba Sun, Zhiyong The Department of Automatic Control LTH Lund University Sweden Department of Electrical Engineering Eindhoven University of Technology Netherlands

Motivated by the penetration of converter-based generation into the electrical grid, we revisit the classical log-linear learning algorithm for optimal allocation of synchronous machines and converters for mixed power generation. The objective is to assign to each generator unit a type (either synchronous machine or DC/AC converter in closed-loop with droop control), while minimizing the steady state angle deviation relative to an optimum induced by unknown optimal configuration of synchronous and DC/AC converter-based generation. Additionally, we study the robustness of the learning algorithm against a uniform drop in the line susceptances and with respect to a well-defined feasibility region describing admissible power deviations. We show guaranteed probabilistic convergence to maximizers of the perturbed potential function with feasible power flows and demonstrate our theoretical findings via simulative examples of power network with six generation units. Copyright © 2020, The Authors. All rights reserved.

关键词： Learning algorithms

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Analysis of the accuracy of the estimation of signal arrival angle in monostatic MIMO radar using the Capon algorithm and its modifications

Analysis of the accuracy of the estimation of signal arrival...

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International Radar Symposium (IRS)

作者： Błażej Ślesicki Anna Ślesicka Adam Kawalec Department of Avionics and Control Systems Faculty of Aviation Division Military University of Aviation Dęblin Poland Institute of Navigation Military University of Aviation Dęblin Poland Department of Anti-Aircraft Missile Sets Faculty of Mechatronics Armament and Aerospace Military University of Technology Warsaw Poland

ISBN: (数字)9788395602054

ISBN: (纸本)9781665466301

This paper presents an analysis of the feasibility of using a modified Capon algorithm for signal arrival angle estimation in a MIMO (Multiple-Input-Multiple-Output) monostatic radar. A comprehensive analysis of the state of the art in signal arrival angle estimation algorithms used in many fields of technology, not only in radiolocation, has been carried out. The methodology of simulation studies preparing the newly implemented algorithm for operation in a radar system is presented. A change from the traditional Capon algorithm was proposed in that instead of inverting the entire covariance matrix of the received data, only the upper triangular matrix R formed by decomposing the QR of the covariance matrix of the received data into the orthogonal matrix Q and the upper triangular matrix R was subjected to the inversion operation. The presented research is a comprehensive view on adaptation of angle of arrival estimation algorithms in various fields of technology, which so far has been presented in a selective manner or does not necessarily take into account all technical aspects that have a significant influence on the application of the developed algorithm in real systems. The idea of using signal arrival angle estimation algorithms and the influence of signal to noise ratio on the quality of object detection are presented. The presented results of simulation studies confirm the validity of the proposed approach to signal arrival angle estimation algorithms in MIMO monostatic radar.

关键词： MIMO radar Simulation Estimation Object detection Radar applications Matrix decomposition Covariance matrices

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Positive Invariance of Subset of Positive Externalities

Positive Invariance of Subset of Positive Externalities

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European control Conference (ECC)

作者： Adrianto Ravi Ibrahim Tomohisa Hayakawa Department of Systems and Control Engineering Tokyo Institute of Technology Tokyo Japan

ISBN: (数字)9783907144022

ISBN: (纸本)9781728188133

The notion of subset of positive externalities is explored. The subset of positive externalities for games by two pseudo-gradient agents with quadratic payoffs is characterized. It is shown that only a certain subset of the subset of positive externalities can be a positively invariant set of the pseudo-gradient dynamics. A necessary and sufficient condition such that this subset is a positively invariant set of the pseudo-gradient dynamics is given. The results are illustrated with an example.

关键词： Games Nash equilibrium Trajectory Eigenvalues and eigenfunctions Solids Europe Complex systems

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Distributed Event-Triggered Algorithm for Convex Optimization with Coupled Constraints

arXiv

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arXiv 2022年

作者： Huang, Yi Zeng, Xianlin Meng, Ziyang Sun, Jian School of Automation Beijing Institute of Technology Beijing100081 China State Key Laboratory of Intelligent Control and Decision of Complex Systems School of Automation Beijing Institute of Technology Beijing100081 China Department of Precision Instrument Tsinghua University Beijing100084 China Chongqing Innovation Center Beijing Institute of Technology Chongqing401120 China

This paper develops a distributed primal-dual algorithm via event-triggered mechanism to solve a class of convex optimization problems subject to local set constraints, coupled equality and inequality constraints. Different from some existing distributed algorithms with the diminishing step-sizes, our algorithm uses the constant step-sizes, and is shown to achieve an exact convergence to an optimal solution with an O(1/k) convergence rate for general convex objective functions, where k > 0 is the iteration number. Moreover, by applying event-triggered communication mechanism, the proposed algorithm can effectively reduce the communication cost without sacrificing the convergence rate. Finally, a numerical example is presented to verify the effectiveness of the proposed algorithm. Copyright © 2022, The Authors. All rights reserved.

关键词： Convex optimization

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Suppressing the endemic equilibrium in SIS epidemics: A state dependent approach

arXiv

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arXiv 2021年

作者： Wang, Yuan Gracy, Sebin Ishii, Hideaki Johansson, Karl Henrik Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Digital Futures Stockholm Sweden Department of Computer Science Tokyo Institute of Technology

This paper considers the susceptible-infected-susceptible (SIS) epidemic model with an underlying network structure and focuses on the effect of social distancing to regulate the epidemic level. We demonstrate that if each subpopulation is informed of its infection rate and reduces interactions accordingly, the fraction of the subpopulation infected stays below half for all time instants. To this end, we first modify the basic SIS model by introducing a state dependent parameter representing the frequency of interactions between subpopulations. Thereafter, we show that for this modified SIS model, the spectral radius of a suitably-defined matrix being not greater than one causes all the agents, regardless of their initial sickness levels, to converge to the healthy state;assuming non-trivial disease spread, the spectral radius being greater than one leads to the existence of a unique endemic equilibrium, which is also asymptotically stable. Finally, by leveraging the aforementioned results, we show that the fraction of (sub)populations infected never exceeds half. Copyright © 2021, The Authors. All rights reserved.

关键词： Epidemiology

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