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Design of Molecular Screen Generating Ultra-High Vacuum for Production of Semiconductive Materials Using Molecular Beam Epitaxy Technology on The Chinese Space Station 74

Design of Molecular Screen Generating Ultra-High Vacuum for ...

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74th International Astronautical Congress, IAC 2023

作者： Liu, Hao Wang, Yifan Su, Dandan Panfilov, Yuri V. Gu, Lingyun Dong, Ge School of Aerospace Engineering Tsinghua University 30 Shuangqing Street Haidian Dis. Beijing100084 China Department of Mechanical Engineering Technologies Bauman Moscow State Technical University 5/1 ul. Baumanskaya 2-ya Moscow105005 Russia Department of Automatic Control Systems Bauman Moscow State Technical University 5/1 ul. Baumanskaya 2-ya Moscow105005 Russia

Molecular beam epitaxy (MBE), a technique for depositing multilayer high-quality thin films at the atomic level, has an important role in the manufacture of semiconductor materials and is the most promising technology for modern electronic and communication devices. To obtain impurity-free homogeneous thin films, MBE requires an ultra-high vacuum producing environment. However, maintaining such an environment on Earth is challenging due to high cost. According to statistics from Siberian Institute of Semiconductors and Physics, over 75% of the cost is spent on vacuum pumping and energy consumption. As the cost of entering space continues to decrease, we propose to implement semiconductor production with MBE in space. Specifically, using the Chinese Space Station (CSS) to haul a molecular screen (MS), when the MS travels at 7.9 km/s, the gas density behind the MS decreases significantly, and the pressure is approximately 10-8-10-10 Pa, which meets the requirements of MBE technology. In order to design a MS that meets the requirements, its material and structure need to be investigated. In this paper, a metal matrix composite is designed to reduce the outgassing rate of the MS under the influence of space radiation and temperature changes. In terms of the structural design of the MS, we propose a deformable disk-shaped structure, which is in shrinking state during rocket's launch to save load space and spreads out after entering space. The front of the MS serves as a natural barrier, preventing gas molecules and particles with low thermal motion velocities from entering the MBE growth area. The periphery of the MS is angled at 45° to the front to prevent hydrogen and helium molecules with high thermal motion velocities diffusing into the wake region from the side. In summary, we design a MS that creates conditions for using MBE technology to produce semiconductor materials in space. Further, a prototype of MS with a diameter of 450 mm and a weight of 30 kg will be sen

关键词： Molecular beam epitaxy Molecular screen Semiconductor Space manufacturing Ultrahigh vacuum

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Non-linear control of the Power Injected Into a Weak Grid by a Self-Synchronized Inverter

arXiv

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arXiv 2024年

作者： Jorge, Sebastian Gomez Solsona, Jorge A. Busada, Claudio A. Aguirre-Larrayoz, Leire C. Martínez, M. Itsaso Tapia-Otaegui, Gerardo CONICET and Dpto. Ing. Eléctrica y de Computadoras UNS Bahía Blanca Argentina The Department of Automatic Control and Systems Engineering University of the Basque Country UPV/EHU Faculty of Engineering–Gipuzkoa Donostia20018 Spain

In this work, a non-linear controller designed using non-linear transformation linearization and feedback is proposed for an inverter connected to a weak grid through a single-stage inductive filter. The proposed strategy is self-synchronized, so that it is not necessary to have a voltage sensor at the Point of Common Coupling (PCC). The strategy allows to robustify, in the presence of a weak grid, a strategy that has already been demonstrated to allow a significant reduction in the size of the DC-link capacitor of the converter. For this purpose, a state observer is designed that allows estimating the voltage at the PCC from the measurement of the output inductor current. A start-up controller is also included, which allows synchronization even in the case of system start-up. Simulation results are presented for different operating cases, including start-up, normal operation, and grid-voltage sags and swells. In all these cases, it is considered that the exact parameters of the grid to which the inverter is connected are unknown. © 2024, CC BY-SA.

关键词： Linear control systems

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Correlation of Optical Properties to Mechanical Degradation of 3D Printed Thermoplastic Polyurethane Polymers Subjected to Gamma Irradiation

Correlation of Optical Properties to Mechanical Degradation ...

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2022 International Conference on Electrical, Computer, Communications and Mechatronics engineering, ICECCME 2022

作者： Gharaibeh, Belal M.Y. Salaimeh, Ahamad A. Jararweh, Mohammed Wasel Al-Omari, Ali Alalaween, Wafa'H. Mahfouf, Mahdi Department of Industrial Engineering Collage of Engineering and Applied Sciences Amerincan University of Kuwiat Salmiya Kuwait The University of Jordan Amman Jordan Mechanical Engineering Department University of Kentucky Lexington United States Supply Chain and Planning Department Hikma Pharmaceuticals PIc Amman Jordan Extraction Department Jordanian Uranium Mining Company Amman Jordan The University of Jordan Department of Industrial Engineering Amman Jordan The University of Sheffield Department of Automatic Control and Systems Engineering Sheffield United Kingdom

ISBN: (数字)9781665470957

ISBN: (纸本)9781665470957

Polymeric medical grade materials subjected to sterilization gamma irradiation doses of medical devises and tools have been studied in this research work. Thermoplastic Polyurethane polymer specimens made by additive manufacturing method of Fused Deposition Modeling subjected to medical sterilization ranges of gamma Irradiation doses at room temperature of 12.5, 15, 20, 25, and 30 kGy were tested for mechanical, chemical and color changes due to the irradiation doses relative to control sample of 0 kGy dose. Reduction in elongation and tensile strength was observed and no significant chemical bonds changes has been observed due to low doses of gamma irradiation which is expected for TPU materials. Color changed from white transparent appearance to a yellow shade as expected due to irradiation reaching 26.7% change in intensity for the 30 kGy irradiation dose. A Levenberg - Marquardt training algorithm of two inputs and a single output were trained using Artificial Neural Network (ANN)-to correlate the color change to % elongation changes due to the single input of gamma irradiation dose and the determination coefficients are as good in the learning set as in the testing having a regression value of (R=0.9998) with validation (R=1). © 2022 IEEE.

关键词： Elongation

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Design of a Lifting-Body Earth Return Orbiter for Mars Expedition Missions 74

Design of a Lifting-Body Earth Return Orbiter for Mars Exped...

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74th International Astronautical Congress, IAC 2023

作者： Liu, Hao Su, Dandan Wang, Yifan Dong, Ge School of Aerospace Engineering Tsinghua University 30 Shuangqing Street Haidian Dis. Beijing100084 China Department of Automatic Control Systems Bauman Moscow State Technical University 5/1 ul. Baumanskaya 2-ya Moscow105005 Russia Department of Mechanical Engineering Technologies Bauman Moscow State Technical University 5/1 ul. Baumanskaya 2-ya Moscow105005 Russia

Mars has been the primary target for deep space expedition for decades, with nations such as the USA, Europe, and China unveiling their own plans for expedition. Among the most common earth return orbiter (ERO) designs are blunt-headed return capsules (e.g. Soyuz, Apollo, Dragon, Shenzhou), as well as winged multi-trip vehicles (e.g. Space Shuttle and Buran). Each of these spacecraft has its own set of advantages and disadvantages depending on the mission. During the Earth re-entry phase of a Mars expedition ERO, the blunt-head return capsule has a low lift-to-drag ratio (L/D) of K=0.2…0.5, resulting in high velocity upon arrival back on Earth. This could lead to an overload exceeding 8g, which poses a significant health risk for astronauts who have experienced prolonged weightlessness. Meanwhile, the Space Shuttle's L/D is too high, ranging from 1 to 4.5, leading to a longer return time to Earth that could be detrimental in an emergency situation. To address these issues, this paper proposes a lifting-body ERO design with a L/D ranging from 0.8 to 2.5. Its unique aeroballistics, aerothermodynamics, and mass properties make it appropriate for a Martian expedition system. As a result, the lifting-body ERO has the potential to extend the reentry corridor L=2500km, reduce waiting time in orbit, and land in a designated area at any time of day. Additionally, the lifting-body ERO could descend at a lower overload of G= 1…3g compared to the 4…8g overload of gliding or ballistic descent orbiters, which is particularly important for astronauts prolonged exposure to weightlessness. In order to design the lifting body ERO for a Martian expedition system, the mass characteristics of the lifting-body ERO are determined based on its intended purpose, overall dimensions, and aerodynamic shape. Using Newtonian theory, the aerodynamic characteristics of the ERO during the hypersonic descent phase are calculated. To determine the ballistic characteristics of the vehicle, the system

关键词： Ballistic Characteristics Lift-to-Drag Ratio Lifting-Body Mars Expedition Overload Spacecraft

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Convergence rates for an inexact linearized ADMM for nonsmooth nonconvex optimization with nonlinear equality constraints

arXiv

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arXiv 2025年

作者： Bourkhissi, Lahcen El Necoara, Ion Automatic Control and Systems Engineering Department National University of Science and Technology Politehnica Bucharest Bucharest060042 Romania Gheorghe Mihoc-Caius Iacob Institute of Mathematical Statistics and Applied Mathematics The Romanian Academy Bucharest050711 Romania

In this paper, we consider nonconvex optimization problems with nonsmooth nonconvex objective function and nonlinear equality constraints. We assume that both the objective function and the functional constraints can be separated into 2 blocks. To solve this problem, we introduce a new inexact linearized alternating direction method of multipliers (ADMM) algorithm. Specifically, at each iteration, we linearize the smooth part of the objective function and the nonlinear part of the functional constraints within the augmented Lagrangian and add a dynamic quadratic regularization. We then compute the new iterate of the block associated with nonlinear constraints inexactly. This strategy yields subproblems that are easily solvable and their (inexact) solutions become the next iterates. Using Lyapunov arguments, we establish convergence guarantees for the iterates of our method toward an ϵ-first-order solution within O(ϵ−2) iterations. Moreover, we demonstrate that in cases where the problem data exhibit e.g., semi-algebraic properties or more general the KL condition, the entire sequence generated by our algorithm converges, and we provide convergence rates. To validate both the theory and the performance of our algorithm, we conduct numerical simulations for several nonlinear model predictive control and matrix factorization problems. © 2025, CC BY.

关键词： Matrix factorization

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Client-server Mobile System for Diagnosis of Asynchronous Motors 4

Client-server Mobile System for Diagnosis of Asynchronous Mo...

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4th IEEE KhPI Week on Advanced Technology, KhPI Week 2023

作者： Chorna, Olha Kurliak, Petro Busher, Victor Chornyi, Oleksii Tytiuk, Valerii Zachepa, Iurii Institute of Education and Science in Electrical Engineering and Information Technologies Kremenchuk Mykhailo Ostrogradskyi National University Kremenchuk Ukraine Department of Electrical Power Engineering Electrical Engineering And Electromechanics Ivano-Frankivsk National Technical University of Oil and Gas Ivano-Frankivsk Ukraine Dept. of Electrical Engineering and Electronics National University "Odessa Maritime Academy" Odessa Ukraine Department of Electromechanics Kryvyi Rih National University Kryvyi Rih Ukraine Department of Systems of Automatic Control and Electric Drive Kremenchuk Mykhailo Ostrohradskyi National University Kremenchuk Ukraine

ISBN: (纸本)9798350395532

This paper presents client-server mobile system for diagnosis of asynchronous motors. The system is created as a mobile application for smartphones and tablets. The system provides processing of the measured values of the currents and voltages of the stator phases of the asynchronous motor. According to the processing results, the results of diagnostics and forecasting of the current state of asynchronous motors are calculated. The software runs on the Android OS. The main purpose is to predict the current state of AD, which has a parametric electromagnetic asymmetry of the stator phases. © 2023 IEEE.

关键词： Induction motors

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Design of a Navigation Function for a Polyhedral World 16th

Design of a Navigation Function for a Polyhedral World

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16th APCA International Conference on automatic control and Soft Computing, controlO 2024

作者： Nicu, Theodor-Gabriel Stoican, Florin Ioan, Daniel Prodan, Ionela Department of Automatic Control and Systems Engineering Romania National University of Science and Technology "Politehnica" Bucharest 313 Splaiul Independenţei Bucharest060042 Romania Univ. Grenoble Alpes Grenoble INP Institute of Engineering and Management LCIS Valence26000 France

ISBN: (纸本)9783031817236

This work pertains to the generation of navigation functions for obstacle avoidance and target tracking. One initially defines a so-called spherical world which can be further mapped into many other different topologies using a series of diffeomorphic transformations. This specific configuration further allows one to exploit the main advantages of the sum function approach with respect to the obstacle collision avoidance capabilities of an agent, sum function which is used in order to induce an effective navigation function judging not only from computational perspective, but also from the local minima point of view. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： Topology

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Sallen-Key High-Pass Filter with Unrelated Tune of Generic Parameter 23

Sallen-Key High-Pass Filter with Unrelated Tune of Generic P...

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23rd IEEE International Conference of Young Professionals in Electron Devices and Materials, EDM 2022

作者： Denisenko, Darya Yu. Prokopenko, Nikolay N. Ivanov, Yuri I. Butyrlagin, Nikolay N. Don State Technical University Department of Scientific Research Rostov-on-Don Russia Southern Federal University Department of Automatic Control Systems Rostov-on-Don Russia Department of Information Systems and Radio Engineering Don State Technical University Zelenograd Rostov-on-Don Russia Institute for Design Problems in Microelectronics of Russian Academy of Sciences Zelenograd Rostov-on-Don Russia

ISBN: (纸本)9781665498043

New second order high-pass filter of the Sallen-Key family circuit is considered, where there is unrelated tune of generic parameters by a digitally controlled resistor - the pole frequency, Q-factor pole and the scale transfer coefficient. The basic mathematical expressions of transfer function for proposed high-pass filter are obtained. A comparison of the parameters of the known and new schemes is given. A Sallen-Key high-pass filter circuit based on a high-frequency emitter follower has been developed. The results of high-pass filter modeling in the Micro-Cap 12 environment using the OP37 operational amplifier and an ideal buffer amplifier are presented. Computer simulation has shown that the pole frequency is adjusted by resistor R5. Adjusting the pole attenuation is possible by changing the resistor R3, while the pole attenuation frequency unchanged, an increase in R3 leads to an increase of the pole attenuation. © 2022 IEEE.

关键词： Operational amplifiers

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Asymmetry of the Relative Entropy in the Regularization of Empirical Risk Minimization

arXiv

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arXiv 2024年

作者： Daunas, Francisco Esnaola, Iñaki Perlaza, Samir M. Vincent Poor, H. The Department of Automatic Control & Systems Engineering The University of Sheffield SheffieldS1 3JD United Kingdom INRIA Centre Inria d'Université Côte d'Azur Sophia Antipolis06902 France The Department of Automatic Control and Systems Engineering The University of Sheffield SheffieldS1 3JD United Kingdom The Department of Electrical and Computer Engineering Princeton University PrincetonNJ08544 United States The GAATI Mathematics Laboratory University of French Polynesia Fa'a'ā98702 French Polynesia

The effect of relative entropy asymmetry is analyzed in the context of empirical risk minimization (ERM) with relative entropy regularization (ERM-RER). Two regularizations are considered: (a) the relative entropy of the measure to be optimized with respect to a reference measure (Type-I ERM-RER);or (b) the relative entropy of the reference measure with respect to the measure to be optimized (Type-II ERM-RER). The main result is the characterization of the solution to the Type-II ERM-RER problem and its key properties. By comparing the well-understood Type-I ERM-RER with Type-II ERM-RER, the effects of entropy asymmetry are highlighted. The analysis shows that in both cases, regularization by relative entropy forces the solution's support to collapse into the support of the reference measure, introducing a strong inductive bias that can overshadow the evidence provided by the training data. Finally, it is shown that Type-II regularization is equivalent to Type-I regularization with an appropriate transformation of the empirical risk function. © 2024, CC BY.

关键词： Risk assessment

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Risk-Sensitive RL Using Sampling-Based Expectation-Maximization

Risk-Sensitive RL Using Sampling-Based Expectation-Maximizat...

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IEEE Conference on Decision and control

作者： Erfaun Noorani John S. Baras Karl H. Johansson Department of Electrical and Computer Engineering Institute for Systems Research (ISR) at the University of Maryland College Park MD USA Automatic Control Lab Royal Institute of Technology Stockholm Sweden

There is a need for robust Reinforcement Learning (RL) algorithms that can cope with model misspecification, parameter uncertainty, disturbances, etc. Risk-sensitive methods offer an approach to developing robust RL algorithms by hedging against undesirable outcomes in a probabilistic manner. The Probabilistic Graphical Model (PGM) framework offers systematic exploration for risk-sensitive RL. In this paper, we bridge the Markov Decision Process (MDP) and the PGM frameworks. We exploit the equivalence of optimizing a certain risk-sensitive criterion in the MDP formalism with optimizing a log-likelihood objective in the PGM formalism. By utilizing this equivalence, we offer an approach for developing risk-sensitive algorithms by leveraging the PGM framework. We explore the Expectation-Maximization (EM) algorithm under the PGM formalism. We show that risk-sensitive policy gradient methods can be obtained by applying sampling-based approaches to the EM algorithm, e.g., Monte-Carlo EM, with the log-likelihood. We show that Monte-Carlo EM leads to a risk-sensitive Monte-Carlo policy gradient algorithm. Our simulations illustrate the risk-sensitive nature of the resulting algorithm.

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