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arXiv 2024年

作者： Ebihara, Yoshio Sebe, Noboru Waki, Hayato Peaucelle, Dimitri Tarbouriech, Sophie Magron, Victor Hagiwara, Tomomichi Graduate School of Information Science and Electrical Engineering Kyushu University Fukuoka819-0395 Japan Department of Intelligent and Control Systems Kyushu Institute of Technology Fukuoka820-8502 Japan Institute of Mathematics for Industry Kyushu University Fukuoka819-0395 Japan LAAS-CNRS Université de Toulouse CNRS ToulouseF-31400 France Department of Electrical Engineering Kyoto University Kyoto615-8510 Japan

This paper is concerned with the analysis of the Lp (p ∈ [1, ∞), p = ∞) induced norms of continuous-time linear systems where input signals are restricted to be nonnegative. This norm is referred to as the Lp+ induced norm in this paper. It has been shown recently that the Lp+ induced norm is effective for the stability analysis of nonlinear feedback systems where the nonlinearity returns only nonnegative signals. However, the exact computation of the Lp+ induced norm is essentially difficult. To get around this difficulty, in the first part of this paper, we provide a copositive-programming-based method for the upper bound computation by capturing the nonnegativity of the input signals by copositive multipliers. Then, in the second part of the paper, we derive uniform lower bounds of the Lp+ (p ∈ [1, ∞), p = ∞) induced norms with respect to the standard Lp induced norms that are valid for all linear systems including infinite-dimensional ones. For each linear system, we finally derive a computation method of the lower bounds of the Lp+ induced norm that are larger than (or equal to) the uniform one. The effectiveness of the upper/lower bound computation methods are fully illustrated by numerical examples. Copyright © 2024, The Authors. All rights reserved.

关键词： Linear systems

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Prototype and Simulation Model of a Robotic Hand

Prototype and Simulation Model of a Robotic Hand

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Mechatronics systems and Materials (MSM)

作者： Rafal Kordaczek Adam Krzysztof Piłat Department of Automatic Control and Robotics AGH University of Science and Technology Kraków Poland

ISBN: (数字)9781728169569

ISBN: (纸本)9781728169576

This elaboration describes the whole process of robotic hand design and modelling in order to improve some of the key performance aspects of tendon driven mechanisms. The hand model is simulated in Simscape Multibody Environment to accurately predict the performance of various designs. Some of developed mechanical solutions lead to reducing the wear, improving torque figures and enhancing rigidity.

关键词： Tendons Torque Prototypes Robots Thumb Pulleys Force

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Fabrication of UV Photodetectors Based on Photoelectrochemically Etched Nanoporous Silicon: Effect of Etchants Ratio

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Journal of Nanomaterials 2023年第1期2023卷

作者： Thahe, Asad A. Qaeed, Motahher A. Abdullah, Suhail Najm Badawy, Ibrahim M. Alqaraghuli, Hasan Alajerami, Yasser Saleh Mustafa Mindil, A. Al-Farga, Ammar Department of Medical Physics College of Applied Science University of Fallujah Baghdad Iraq Faculty of Science University of Jeddah Jeddah Saudi Arabia Department of Medical Equipment Technology Engineering Al-Rasheed University College Baghdad Iraq Energy Materials Laboratory School of Sciences and Engineering The American University in Cairo New Cairo11835 Egypt Faculty of Electrical Engineering Mechatronics and Automatic Control Department University of Technology Malaysia Johor Bahru81310 Malaysia Faculty of Applied Medical Sciences Medical Imaging Department Al-Azhar University-Gaza Gaza Palestine Faculty of Science Department of Biochemistry University of Jeddah Jeddah Saudi Arabia

Despite several attempts to enhance the electrical and charge carrier transport characteristics of porous silicon (PSi), the requisite conditions for optimally synthesizing n-PSi with appealing optoelectronic properties are yet to be achieved. Therefore, this research explores the effect of the chemical ratio of precursor materials (HF:C2H6O:H2O2) on the surface morphology, crystalline structure, and optical and electric properties of PSi. The PSi was produced by photoelectrochemical etching followed by anodization of the n-type Si under light illumination. The properties of the as-prepared PSi were studied by means of microscopic and spectroscopic techniques. The HF:C2H6O:H2O2 chemical ratio was optimized at 2: 1: 1. A metal-semiconductor-metal (MSM) ultraviolet photodetector (Pt/n-PSi/Pt) was fabricated, which exhibited high performances under UV light (365 nm) illumination. The photodetector was shown to be highly stable and reliable with a rapid rise time of 0.56 s at a bias voltage of +5 V. The MSM photodetector displayed responsivity (Rp) of 9.17 A/m at 365 nm, which significantly exceeds the values reported for TiC/porous Si/Si in some contemporary research. The photodetector fabricated from n-PSi, synthesized at an optimum chemical ratio (2: 1: 1) exhibited the best photodetection performance, possibly due to the high porosity and defect-free state of the n-PSi thin films. © 2023 Asad A. Thahe et al.

关键词： Fabrication

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Efficiency of stochastic coordinate proximal gradient methods on nonseparable composite optimization

arXiv

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arXiv 2021年

作者： Necoara, Ion Chorobura, Flavia Automatic Control and Systems Engineering Department University Politehnica Bucharest Bucharest060042 Romania Gheorghe Mihoc-Caius Iacob Institute of Mathematical Statistics and Applied Mathematics The Romanian Academy Bucharest050711 Romania

This paper deals with composite optimization problems having the objective function formed as the sum of two terms, one has Lipschitz continuous gradient along random subspaces and may be nonconvex and the second term is simple and differentiable, but possibly nonconvex and nonseparable. Under these settings we design a stochastic coordinate proximal gradient method which takes into account the nonseparable composite form of the objective function. This algorithm achieves scalability by constructing at each iteration a local approximation model of the whole nonseparable objective function along a random subspace with user-determined dimension. We outline efficient techniques for selecting the random subspace, yielding an implementation that has low cost per-iteration while also achieving fast convergence rates. We present a probabilistic worst-case complexity analysis for our stochastic coordinate proximal gradient method in convex and nonconvex settings, in particular we prove high-probability bounds on the number of iterations before a given optimality is achieved. Extensive numerical results also confirm the efficiency of our algorithm. © 2021, CC BY.

关键词： Gradient methods

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Fast Trajectory Planning for Dubins Vehicles Under Cumulative Probability of Radar Detection

SSRN

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SSRN 2022年

作者： Li, Zhuo You, Keyou Sun, Jian Song, Shiji State Key Lab of Intelligent Control and Decision of Complex Systems School of Automation Beijing Institute of Technology Beijing100081 China Department of Automation and BNRist Tsinghua University Beijing100084 China Beijing Institute of Technology Chongqing Innovation Center Chongqing401120 China

This paper studies a minimum-time trajectory planning problem under radar detection, where a Dubins vehicle aims to attack a target with a limited probability of being detected. Since the probability is accumulated along the vehicle's trajectory in an integral form, we have to address a non-convex constrained functional optimization problem. To this end, Pontryagin's minimum principle is first adopted to derive the optimality condition, based on which we obtain a set of parameterized trajectories that contains all the optimal ones. Then, fast algorithms are proposed to approximately compute a minimum-time trajectory among the set. Simulations are performed to validate the effectiveness and efficiency of the proposed planning algorithms. © 2022, The Authors. All rights reserved.

关键词： Probability

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Study of photophysical properties of Cdq2 thin film

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Materials Today: Proceedings 2022年 66卷 202-204页

作者： Lougdali, M. El Kouari, Y. Anoua, R. Zazoui, M. El Oudghiri-Idrissi, I. Abboud, Y. Zawadzka, A. Sahraoui, B. Laboratory of Materials Energy and Control System Faculty of Sciences and Technology Hassan II University of Casablanca Mohammedia B.P 146 Morocco Department of Automatic and Measurement Faculty of Physics Astronomy and Informatics Nicolaus Copernicus University Torun Poland Laboratory of Engineering Sciences for Energy National School of Applied Sciences of El Jadida El Jadida BP 1166 Morocco Faculty of Sciences Ben M'sik University of Hassan II of Casablanca Casablanca Morocco Centre for Modern Interdisciplinary Technologies Nicolaus Copernicus University Wilenska 4 Torun 87-100 Poland MOLTECH-Anjou UMR 6200 CNRS UNIV Angers 2 bd Lavoisier Angers 49045 France

In this work, the morphological and optical properties of the cadmium (II) bis(8-hydroxyquinoline) (Cdq2) thin film are presented. The film was elaborated by physical deposition technique. The Atomic Force Microscopy (AFM) image shows a homogenous surface. The transmittance was measured in the range of 300–1200 nm with UV–visible spectroscopy. The emission of the film was characterized via the photoluminescence spectroscopy, a strong luminescence has been found. The measurements done at low temperatures show a decrease of the intensity of luminescence in the temperature range of 77–300 K. © 2022

关键词： Thin films

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Wind Tunnel and Numerical Study of Wind Pressure Coefficients on a Medieval Swedish Church

SSRN

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SSRN 2024年

作者： Liu, Wei Mattsson, Magnus Widström, Torun Claesson, Leif Tianjin Key Laboratory of Indoor Air Environmental Quality Control School of Environmental Science and Engineering Tianjin University 92 Weijin Road Tianjin300072 China Department of Civil and Architectural Engineering KTH Royal Institute of Technology Brinellvägen 23 Stockholm100 44 Sweden Department of Building Engineering Energy Systems and Sustainability Science University of Gävle Gävle801 76 Sweden

Air infiltration has great importance regarding energy, comfort, moisture and dust deposition in naturally ventilated historical buildings like churches. In these buildings, air infiltration is driven by stack effect and wind. When assessing the wind effect, reasonable estimation of wind pressure coefficients is crucial. Local wind pressure coefficients are significantly affected by the shape of the building and turbulence generated by its geometrical features, which – for moderately large churches – typically consist of main building body and window recesses, gable roof, tower, apse, and sacristy. This study conducted wind tunnel and numerical investigations of wind pressure coefficients at a church, with gradual addition of these features. Wind pressure was measured on a small-scale model in a wind tunnel, while computational fluid dynamics (CFD) simulations were carried out for both small-scale and full-scale models. By comparing the experimental and numerical results, the SST k − ω turbulence model showed the best accuracy, yielding CFD results in good agreement with wind tunnel measurements. Most challenging was predicting the strong negative wind pressures occurring on a flat roof. Building structures like tower, apse, and sacristy had significant impact on the wind pressures on the central, main building body. This study adds knowledge on wind pressure effects by commonly occurring building components, with particular reference to churches and similar buildings. © 2024, The Authors. All rights reserved.

关键词： Computational fluid dynamics

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Peak Time-Windowed Mean Estimation using Convex Optimization

Peak Time-Windowed Mean Estimation using Convex Optimization

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IEEE Conference on Decision and control

作者： Jared Miller Niklas Schmid Matteo Tacchi Didier Henrion Roy S. Smith Department of Information Technology and Electrical Engineering (D-ITET) ETH Zürich Physikstrasse 3 Automatic Control Laboratory (IfA) and NCCR Automation Zürich Switzerland Univ. Grenoble Alpes CNRS Grenoble INP (Institute of Engineering Univ. Grenoble Alpes) GIPSA-lab Grenoble France LAAS-CNRS Université de Toulouse CNRS Toulouse France and the Faculty of Electrical Engineering Czech Technical University in Prague Czech Republic

ISBN: (数字)9798350316339

ISBN: (纸本)9798350316346

This paper presents an algorithmic approach towards bounding the peak time-windowed average value attained by a state function along trajectories of a dynamical system. An example includes the maximum average current flowing across a power line in any 5 -minute window. The peak time-windowed mean estimation task may be posed as a finite-dimensional but nonconvex optimization problem in terms of an initial condition and stopping time. This problem can be lifted into an infinite-dimensional linear program in occupation measures, where no conservatism is introduced under compactness and dynamical regularity assumptions. The peak time-windowed mean estimation linear program is in turn truncated into a convergent sequence of semidefinite programs using the moment-Sum-of-Squares hierarchy. Bounds of the time-windowed mean are computed for example systems.

关键词： Heuristic algorithms Current measurement Estimation Convex functions Trajectory Dynamical systems Optimization

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Robust control Barrier Function for systems Affected by a Class of Mismatched Disturbances

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SICE Journal of control, Measurement, and System Integration 2020年第4期13卷 165-172页

作者： Takano, Rin Yamakita, Masaki Department of Systems and Control Engineering School of Engineering Tokyo Institute of Technology Japan

This paper proposes a robust exponential control barrier function (RECBF) for systems affected by a class of mismatched disturbances, which forces system states to remain in a given safety set expressed by constraint functions. We consider the case that given constraint functions have different relative degrees for control input and disturbances due to the property of mismatched disturbances, and we extend a concept of the nominal exponential control barrier function (ECBF) to such cases. As a main result, we show RECBF conditions to guarantee invariance of the given safety set and formulate a convex optimization based controller with the RECBF conditions. In particular, we combine a disturbance estimation using Gaussian process regression, which is one of the machine learning methods, with the controller to make use of good properties of RECBF conditions. This formulation enables us to realize robust disturbance compensation based on experimental data, and it can be easily applied to practical systems. We show the effectiveness of the proposed controller through a numerical simulation of a magnetic ball levitation system having model uncertainty. © Taylor & Francis Group, LLC 2020.

关键词： controllers

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Plate Shape Prediction Based on Data-Driven in Roll Quenching Process

Plate Shape Prediction Based on Data-Driven in Roll Quenchin...

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Chinese Automation Congress (CAC)

作者： Liu Hu Luefeng Chen Jie Hu Min Wu Witold Pedrycz Kaoru Hirota School of Automation China University of Geosciences Wuhan China Hubei Key Laboratory of Advanced Control and Intelligent Automation for Complex Systems and the Engineering Research Center of Intelligent Technology for Geo-Exploration School of Automation Ministry of Education China University of Geosciences Wuhan China Department of Electrical and Computer Engineering University of Alberta Edmonton Canada Systems Research Institute Polish Academy of Sciences Warsaw Poland The Department of Computer Engineering Istinye University Sariyer/Istanbul Turkey Tokyo Institute of Technology Yokohama Japan The Tokyo Institute of Technology Tokyo Japan

In the process of steel plate production, predicting the plate shape is of great significance for producing high-quality and consistently stable plate shapes. This paper presents a model that predicts both the defect types and flatness of the plate, providing theoretical support for setting process parameters in roller quenching production. First, the parameters of the quenching process are analyzed to identify their characteristics. Then, the K-Means clustering algorithm and correlation analysis are employed to process the quenching process parameters. A gradient boosting decision tree (GBDT) model is used to predict the defect types and flatness of the steel plates. Finally, industrial production data is utilized for experimental validation. The obtained experimental results verify the reliability of the proposed method.

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