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AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2025

作者： Vanek, Bálint Takarics, Béla Luspay, Tamás Balogh, Dániel Bartasevicius, Julius Kier, Thiemo Konatala, Ramesh Soal, Keith Guerin, Nicolas Kende u. 13.-17 BudapestH-1111 Hungary Technical University of Munich Boltzmannstrasse 15 Garching85748 Germany Institute for System Dynamics and Control Münchener Straße 20 Weßling Germany Institute for Aeroelasticity Bunsenstr. 10 Göttingen Germany 29 avenue de la Division Leclerc Châtillon Cedex92322 France

ISBN: (数字)9781624107238

ISBN: (纸本)9781624107238

This study advances aeroservoelasticity through successful active flutter suppression flight tests on a conventional demonstrator aircraft with advanced control systems. Conducted within the EU-funded FliPASED project involving SZTAKI, DLR, ONERA, and TUM, the primary goal was to mitigate flutter—a critical aeroelastic instability—using active control mechanisms in a specially designed UAV. The methodology included developing precise flexible-aircraft models, creating control algorithms to exceed the design flutter speed, and validating these on the T-FLEX and P-FLEX UAVs. Flight tests in 2023 confirmed the predicted flutter speeds and the effectiveness of two distinct active flutter suppression controllers. The UAVs achieved speeds up to 61 m/s, significantly beyond the critical flutter speed, while a deliberate test without active control at 56 m/s verified the presence of flutter, validating the models’ accuracy. These results underscore the feasibility of active flutter suppression, suggesting potential applications for future commercial aircraft. The FliPASED project also aims to contribute to the scientific community by providing an open-source repository of flight test data to foster further advancements in aeroelasticity. © 2025, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： Aeroservoelasticity

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Design and Evaluation of Nonlinear Inversion Based Automated Landing control for an Airliner in a High Crosswind Scenario

Design and Evaluation of Nonlinear Inversion Based Automated...

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AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2025

作者： Kim, Ho Joong Lombaerts, Thomas Looye, Gertjan Department of Aerospace Engineering San José State University Santa Clara County San JoseCA95121 United States Aerospace Engineering Department Charles W. Davidson College of Engineering United States KBR NASA Ames Research Center Intelligent Systems Division Mail Stop 269-1 Moffett FieldCA94083 United States Institute of System Dynamics and Control German Aerospace Center DLR Weßling82234 Germany

ISBN: (数字)9781624107238

ISBN: (纸本)9781624107238

This paper describes the design and evaluation of an autoflight controller under maximized crosswind landing scenarios using Nonlinear Dynamic Inversion (NDI) and Incremental Nonlinear Dynamic Inversion (INDI) control methods. The simulation model is representative of a nonlinear, 6 DOF twin-engined civilian transport aircraft in landing configuration starting 300 meters above the runway. The designed flight controller is of cascaded control structure based upon the time scale separation principle. While only INDI based design is evaluated, each control loop implements both NDI and INDI based design, accompanied with feed forward path control for select loops. The controller is evaluated through multiple Monte Carlo statistical analyses, each set containing 2000 landings, which are performed under widely distributed environmental and system parameters. The designed INDI method based controller as discussed in this paper satisfies all safe landing criteria for crosswind landings of up to 30 knots. © 2025, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： Aircraft landing

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Research status of creep-fatigue characteristics of salt rocks and stability of compressed air storage in salt caverns

Earth Energy Science

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Earth Energy Science 2025年第1期1卷 98-116页

作者： Marion Fourmeau Wen Liu Zongze Li Daniel Nelias Jinyang Fan Hao Tian Wei Liu Univ Lyon INSA LyonCNRSLaMCoSUMR5259Villeurbanne 69621France State Key Laboratory of Coal Mine Disaster Dynamics and Control School of Resources and Safety EngineeringChongqing UniversityChongqing 400044China Division of Mining and Geotechnical Engineering LuleåUniversity of Technology97187 LuleåSweden

Energy is an important resource that supports the development of human society,and energy security is even more relevant to the strength of a *** order to ensure energy security,countries around the world are taking measures to carry out energy transformation and construct new energy *** an important part of the new energy system,energy storage technology is highly valued by all *** many large-scale energy storage technologies,salt cavern compressed air energy storage(CAES)technology stands out for its safety and economy,which is recognized and valued by scholars from various *** the construction of salt cavern CAES power station,it is very important to ensure the stability of salt ***,scholars have investigated the mechanical properties of salt rocks and the stability of salt caverns for *** paper synthesizes the findings of current research on the creep and fatigue properties of salt rock,highlighting three key points:The factors influencing the creep and fatigue characteristics of salt rock include its composition,stress levels,and ***,impurities and surrounding pressure tend to inhibit the deformation of salt rock,whereas elevated temperature and differential stress facilitate its deformation;The mechanisms governing creep and fatigue damage in salt rock are primarily associated with dislocation movement and microcracking;Most existing constitutive models for creep and fatigue are based on viscoelastic-plasticity theory,with fewer models derived from micro-mechanical ***,this paper reviews studies on the stability of salt cavern CAES reservoirs utilizing numerical simulation methods and offers insights into future research directions concerning the creep and fatigue properties of salt rocks.

关键词： Salt rock Creep properties Fatigue properties Stability of energy storage

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MODELING AND STABILITY ANALYSIS FOR A CLASS OF INDUSTRIAL REPETITIVE PROCESSES

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INTERNATIONAL JOURNAL OF control 1990年第2期52卷 265-278页

作者： ROGERS, E OWENS, DH Division of Dynamics and Control University of StrathcIyde Glasgow United Kingdom

A mathematical model for a class of linear repetitive, or multipass, processes is developed by reference to a specific example. This is then used to develop the 50- called equivalent discrete conventional linear system to act as a basis for simulation studies. Finally, the stability of this class is completely characterized. © 1990 Taylor and Francis Group, LLC.

关键词： control Systems, Linear

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STABILITY OF HIGH STIFFNESS GAS JOURNAL BEARINGS

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WEAR 1994年第2期172卷 175-183页

作者： CZOLCZYNSKI, K [a]Division of Dynamics of Machines Control Technical University of ?ód? ?ód?Poland

One of the most important problems in the design of gas bearings is their stability. In this paper, results of investigations of the stability of a new type of gas journal bearing, the so-called ''high stiffness bearing'' (HSB) are presented. As linear models of HSB do not allow us to estimate the stability threshold with satisfactory precision, all the numerical experiments carried out have been based on a non-linear model. To calculate the motion of the bearing elements, an iterative method has been used. During the numerical experiments, regions of stable operation of the bearing have been estimated. The appearance of limit cycles points to the non-linear character of the high stiffness bearing.

关键词： Journal bearings

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CLEARANCES BETWEEN THE ROTORS OF HELICAL SCREW COMPRESSORS - THEIR DETERMINATION, OPTIMIZATION AND THERMODYNAMIC CONSEQUENCES

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART E-JOURNAL OF PROCESS MECHANICAL ENGINEERING 1994年第E2期208卷 155-163页

作者： TANG, Y FLEMING, JS Division of Dynamics and Control Department of Mechanical Engineering University of Strathclyde Glasgow Scotland

Although helical screw compressors contain only two moving parts, their shapes are very complicated and must mesh to very fine clearances. The process of determining lobe geometry requires that parts of the male generate parts of the female and vice versa. Once the nominally perfect (zero clearance) profile geometry has been generated, a method for determining clearances is needed which gives an attainable result from the manufacturing and operational viewpoints and gives a thermodynamic efficiency which is at least equal to that of competing machines of the same class. The thermodynamic performance depends principally on the internal leakage rates in the compressor, in particular, the leakage across the contact (sealing) line. This paper presents two ways of setting clearances. They result in different patterns of clearance distribution along the sealing line and have different effects of the thermodynamic performance of the compressor due to the different leakage mass flowrates that they permit. A design technique for obtaining an optimum clearance distribution is discussed. Finally, a thermodynamic model of compressor behaviour is used to predict the performance as influenced by the different clearance distributions, and the predictions are compared with measured values taken from a test compressor. The predictions are shown to be good.

关键词： Machine design

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THE ANALYSIS OF LEAKAGE IN A TWIN-SCREW COMPRESSOR AND ITS APPLICATION TO PERFORMANCE IMPROVEMENT

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART E-JOURNAL OF PROCESS MECHANICAL ENGINEERING 1995年第E2期209卷 125-136页

作者： FLEMING, JS TANG, Y Division of Dynamics and Control Department of Mechanical Engineering University of Strathclyde Glasgow Scotland

The performance of a helical screw compressor is influenced more by the internal gas leakages than by any other thermo-fluid aspect of its behaviour. Six separate types of leakage path can be identified. Only the cusp blow holes have a constant geometry;every other path has a geometry and resistance to flow which varies (periodically) in a manner unique to it. The pressure difference driving the gas along a leakage path also varies (periodically) and does so in a manner that is not the same for every leakage path. This is quite obviously a complex problem requiring insight in modelling the thermo-fluid behaviour and the solution of a large number of simultaneous equations. The distribution of leakage through the various leakage paths within the machine is important for the improvement of the compressor performance. A method of determining the aggregate leakage through each path individually over a complete compression cycle is required to enable this study to be conducted. The authors have constructed a mathematical model of the complete compressor thermofluid process which is suitable for this purpose, its macropredictions having been verified against measured data derived from a test compressor. The nature of its micropredictions and their verification, that is for each leakage path, me the subject of the paper proposed here. Analytical techniques are proposed and experimental methods are discussed. The influence of different rotational speeds on the leakage is considered. Also discussed is the manner in which the leakage distribution prediction could be used to optimize a compressor design.

关键词： TWIN SCREW COMPRESSOR GAS LEAKAGE THERMOFLUID LEAKAGE PATHS THERMODYNAMIC MODEL

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COMPARISON OF SEGMENTATION PROCESSES FOR OBJECT ACQUISITION IN INFRARED IMAGES

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IEE PROCEEDINGS-F RADAR AND SIGNAL PROCESSING 1989年第1期136卷 13-21页

作者： MARKHAM, KC Guidance and Control Department Dynamics Division British Aerospace plc Bristol UK

In this review paper, a qualitative comparison of the performance of nine different segmentation algorithms on a data base of infrared images of vehicles is described. The segmentation methods are categorised according to their mode of operation into three distinct generic classes of algorithm: namely ‘grey level threshold techniques’, ‘three dimensional histogram methods’ and ‘pixel classification techniques’. Each segmentation technique is guided to a subset of the image by a spoke filter detection algorithm which locates regions of the scene that most resemble blob shaped man-made objects. A short list of four segmentation algorithms is compiled, of which two methods from the ‘pixel classification’ class, aK-nearest neighbour (KNN) and a Bayesian algorithm, are selected. The final preference is for the Bayesian technique, the KNN method being less favoured owing to the higher computational burden.

关键词： IR images segmentation processes K-nearest neighbour infrared images picture processing segmentation algorithms spoke filter detection algorithm Pattern recognition Bayesian algorithm Optical information, image and video signal processing object acquisition pixel classification techniques grey level threshold techniques vehicles database three dimensional histogram methods

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Reverse aperiodic resonance in low- to high-dimensional bistable systems: A complement to stochastic resonance studies in logic circuits

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Communications in Nonlinear Science and Numerical Simulation 2025年 149卷

作者： Shen, Mengen Yang, Jianhua Sanjuán, MiguelA.F. Chen, Huatao Wang, Zhongqiu Jiangsu Key Laboratory of Mine Mechanical and Electrical Equipment School of Mechanical and Electrical Engineering China University of Mining and Technology Jiangsu Xuzhou221116 China Nonlinear Dynamics Chaos and Complex Systems Group Departamento de Física Universidad Rey Juan Carlos Tulipán s/n Madrid Móstoles28933 Spain Division of Dynamics and Control School of Mathematics and Statistics Shandong University of Technology Zibo255000 China School of Computer Science and Technology China University of Mining and Technology Jiangsu Xuzhou221116 China

As circuits continue to shrink in size, noise has emerged as a critical challenge in achieving optimal performance. Stochastic resonance in logic circuits offers an innovative approach to harness noise constructively;however, current implementations are limited to basic logical functions such as OR, AND, NOR, and NAND, restricting broader applications. This paper introduces a three-dimensional (3D) coupling model to investigate the counterintuitive phenomena that arise in nonlinear systems under noise. Compared to the one-dimensional Langevin equation and the two-dimensional Duffing equation, the 3D coupling model features more adjustable parameters and coupling interactions, enhancing the system's dynamic behavior. The study demonstrates that increasing noise intensity triggers reverse aperiodic resonance, leading to signal phase reversal and amplitude amplification. This phenomenon is attributed to the motion of Brownian particles in a bistable potential well. Additionally, reverse aperiodic resonance addresses the lack of logical negation in traditional stochastic resonance systems by introducing noise-driven phase reversal, providing a novel alternative to conventional inverters. © 2025 Elsevier B.V.

关键词： Sequential circuits

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Experiments on pilot visibility from a V/STOL in overwater Hover

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Journal of the American Helicopter Society 1971年第4期16卷 19-28页

作者： KURYLOWICH G RITTER A Stability and Control Group Flight Control Division Air Force Flight Dynamics Laboratory Dayton Ohio

11 refs. 31750

关键词： AIRCRAFT, VTOL-STOL

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