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作者： Moss, Robert J. Kochenderfer, Mykel J. Gariel, Maxime Dubois, Arthur Stanford Univ Dept Comp Sci Stanford CA 94305 USA Stanford Univ Dept Aeronaut & Astronaut Stanford CA 94305 USA Xwing San Francisco CA 94102 USA Xwing Engn San Francisco CA 94102 USA

Estimating the probability of failure is an important step in the certification of safety-critical systems. Efficient estimation methods are often needed due to the challenges posed by high-dimensional input spaces, risky test scenarios, and computationally expensive simulators. This work frames the problem of black-box safety validation as a Bayesian optimization problem and introduces a method that iteratively fits a probabilistic surrogate model to efficiently predict failures. The algorithm is designed to search for failures, compute the most-likely failure, and estimate the failure probability over an operating domain using importance sampling. We introduce three acquisition functions that aim to reduce uncertainty by covering the design space, optimize the analytically derived failure boundaries, and sample the predicted failure regions. Results show this Bayesian safety validation approach provides a more accurate estimate of failure probability with orders of magnitude fewer samples and performs well across various safety validation metrics. We demonstrate this approach on three test problems, a stochastic decision-making system, and a neural-network-based runway detection system. This work is open-sourced (https://***/sisl/***) and is currently being used to supplement the FAA certification process of the machine learning components for an autonomous cargo aircraft.

关键词： Flight Recorder Runway Conditions Numerical Analysis Gaussian Mixture Models Convolutional Neural Network Cargo Aircraft Statistical Analysis Aircraft Collision Avoidance Systems computing and informatics Markov Decision Process

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Gauss Equations for Local Action-Angle Orbital Elements in Cislunar Space

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2024年第11期47卷 2273-2286页

作者： Peterson, Luke T. Scheeres, Daniel J. Univ Colorado Boulder Aerosp Engn Sci Boulder CO 80309 USA

To track orbits in cislunar space, predict where they will naturally move over time, and identify where unbounded trajectories come from, one may consider local action-angle orbital elements-coordinates that relate a spacecraft state to specific trajectories and exist in approximately integrable regions of the Earth-moon circular restricted three-body problem (CR3BP). As local action-angle elements are a semi-analytical analog to two-body orbital elements, the theory is extended to allow for the study of arbitrary perturbations to the dynamics. Namely, we derive Gauss equations for an arbitrary perturbing acceleration-continuous or discrete-to the CR3BP. Examples for continuous thrust and impulsive Delta V are provided in cislunar space, i.e., around Earth-moon L1,2 in the CR3BP. Strategies for instantaneous maneuver design and transfers between quasi-periodic orbits and manifolds are developed.

关键词： Space Exploration and Technology Geosynchronous Earth Orbit Planets Solar System Moons Celestial Mechanics International Organizations, Authorities and Agencies Astrodynamics Artificial Satellites Mathematical Analysis computing and informatics

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Automated Processing Method for Chinese NOTAMs Based on Knowledge Graph

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JOURNAL OF AEROSPACE INFORMATION SYSTEMS 2024年第11期21卷 906-913页

作者： Dong, Bing Luo, Chuang Hao, Kuangong Liu, Anquan Li, Xinqian Civil Aviat Flight Univ China Guanghan 618307 Peoples R China

Notice to airmen (NOTAMs) constitutes a vital element in civil aviation operational intelligence. Historically, the processing of these notices has been manual. However, with the significant increase in the number of NOTAMs, issues including low efficiency, time-consuming processes, and high error rates associated with manual processing have become apparent. To address these challenges, we propose an enhanced approach utilizing the Bi-GRU-CRF-Attention model, based on a dataset of 105,797 NOTAMs collected from the Intelligence Center between September 2020 and April 2023. In this methodology, we employ preprocessing techniques to train the model using processed NOTAMs. Subsequently, the trained model is utilized for named entity recognition, identifying entities within the notices, such as status, facilities, and reasons and segmenting sentences into words. Following this, an advanced BERT-DPCNN method is employed to classify the identified entities, yielding triplets comprising NOTAM entities, their categories, and corresponding processing methods. By integrating rule-based approaches, we configure a NOTAM knowledge graph using neo4j. This process establishes an automated NOTAM processing system. This system can autonomously determine the category of a NOTAM upon reception and utilize the Cypher language to query for the appropriate processing method.

关键词： Aircraft Operations Conditional Random Field Civil Aviation Artificial Neural Network Aviation Safety Natural Language Processing Aviation Air Traffic Control Aviation Accidents and Incidents computing and informatics

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Gate-Based Variational Quantum Algorithm for Truss Structure Size Optimization Problem

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AIAA JOURNAL 2024年第12期62卷 4824-4833页

作者： Xu, Yusheng Wang, Xiaojun Wang, Zhenghuan Beihang Univ Natl Key Lab Strength & Struct Integr Inst Solid Mech Sch Aeronaut Sci & Engn Beijing 100191 Peoples R China

Quantum computing has become a pivotal innovation in computational science, offering novel avenues for tackling the increasingly complex and high-dimensional optimization challenges inherent in engineering design. This paradigm shift is particularly pertinent in the domain of structural optimization, where the intricate interplay of design variables and constraints necessitates advanced computational strategies. In this vein, the gate-based variational quantum algorithm utilizes quantum superposition and entanglement to improve search efficiency in large solution spaces. This paper delves into the gate-based variational quantum algorithm for the discrete variable truss structure size optimization problem. By reformulating this optimization challenge into a quadratic, unconstrained binary optimization framework, we bridge the gap between the discrete nature of engineering optimization tasks and the quantum computational paradigm. A detailed algorithm is outlined, encompassing the translation of the truss optimization problem into the quantum problem, the initialization and iterative evolution of a quantum circuit tailored to this problem, and the integration of classical optimization techniques for parameter tuning. The proposed approach demonstrates the feasibility and potential of quantum computing to transform engineering design and optimization, with numerical experiments validating the effectiveness of the method and paving the way for future explorations in quantum-assisted engineering optimizations.

关键词： Trusses computing and informatics Multidisciplinary Design Optimization Optimization Algorithm Evolutionary Algorithm Annealing Structural Optimization Quantum computing

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Statistical Characterization of Emitter Fabrication over Electrospray Array Thruster

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JOURNAL OF PROPULSION AND POWER 2024年第6期40卷 896-904页

作者： Whittaker, Collin B. Jorns, Benjamin A. Univ Michigan Dept Aerosp Engn Ann Arbor MI 48109 USA

A method for characterizing the variance in fabrication of emitters and extractors in a porous conical electrospray array thruster is presented. Coherence scanning interferometry is used to produce topographic maps of 543 of 576 sites within the array. The emitter and extractor geometries, features of size a few hundred micrometers, are modeled as a spherically capped cone recessed from a circular aperture. Regressing this model against the topographic maps yields a set of salient parameters that describe the geometry of a site, including the tip radius and height of the emitter and its offset from the extractor aperture. Statistics over the emitter geometries are computed, which represent manufacturing tolerances. It is found that key parameters like the emitter tip radius are highly variable (mean 25.8 mu m and standard deviation 20.9 mu m), highlighting the stochastic nature of the manufacturing process. Correlations between the tip radius and emitter height indicate that this variability arises from blunting of the emitters during fabrication, and the observation that emitters are shorter than nominal is explained by an increase in effective cutting diameter of the tools. Further analysis indicates that determining the mean emitter tip radius of the entire population within 5% error requires over 300 individual emitter measurements. These results indicate that accurately quantifying emitter variability at scale requires rigorous and extensive analysis, and the implications of this emitter variability for device performance and design are discussed.

关键词： Electrospray Thruster Statistical Analysis computing and informatics Computational Modeling Surface Properties Electrospray Emitters Electric Propulsion Uncertainty Quantification Microfluidics

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Improving Spacecraft Reliability Through Digital Transformation

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JOURNAL OF AEROSPACE INFORMATION SYSTEMS 2024年第5期21卷 422-429页

作者： Gordon, Nathaniel G. Boschetti, Nicolo Marsili, Damiano Falco, Gregory Cornell Univ Sibley Sch Mech & Aerosp Engn Ithaca NY 14853 USA Johns Hopkins Univ Comp Sci Baltimore MD 21211 USA

This paper demonstrates the reliability engineering benefit achievable by spacecraft digital transformation. The space industry has evolved in the past decade to increasingly incorporate new computing practices into the sector's ground service and backoffice operations, hailed as a "digital transformation" of their information technology (IT) infrastructure. Parallel sectors that heavily engage control systems, such as utilities and manufacturing, have not only embraced an IT digital transformation but also incorporated new computing architectures, chipsets, and data processing techniques into their operational technology (OT) systems. The space sector has lagged to adopt such digital technologies for their OT, such as spacecraft, and has not realized many of the associated benefits. Through a reliability engineering analysis of small satellites and a comparative case study of a digitally transformed solar sail, we demonstrate the reliability impacts of digital transformation for spacecraft.

关键词： Solar Sail Spacecraft computing and informatics Small Satellites Control Systems Data Processing Aerospace Industry Spacecraft Attitude Control Electromagnetic Interference Fault Tree Analysis

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Engineering Computations and Modeling in MATLAB®/Simulink®

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丛书名： AIAA Education Series

2011年

作者： Oleg A. Yakimenko

ISBN: (数字)9781600867828

ISBN: (纸本)9781600867811

Engineering Computations and Modeling in MATLAB®/Simulink® provides a broad overview of The MathWorks’ MATLAB®/Simulink®/GUIDE development and modeling environment. This textbook shows how to use these software tools effectively in a variety of engineering applications, including modeling real-world dynamic systems. Concepts Discussed: Major concepts of MATLAB®, Symbolic Math Toolbox™, Simulink®, and GUIDE Development of effective foolproof M-file scripts and functions Use of the 2D and 3D plotting functions and handle graphics Creation of interactive user interfaces and animations Presentation of numerical methods, coded in MATLAB® functions Accuracy of digital computations Special Features: Numerous examples Derivation of fundamental formulas using symbolic math computations Dynamic systems modeling in MATLAB® and Simulink® Development of user-friendly standalone GUIs Introduction of aerospace engineering tools This book is used as a textbook by undergraduate and graduate students taking introductory and advanced courses in applied programming, and also as a reference for working professionals using MATLAB®/Simulink®.

关键词： Aerospace Engineering Aerospace Sciences Computer Programming and Language computing and informatics computing, Information, and Communication Software Systems Systems Software

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Introduction to Dynamics and Control of Flexible Structures

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丛书名： AIAA Education Series

1993年

作者： John L. Junkins Youdan Kim

ISBN: (数字)9781600862076

ISBN: (纸本)9781563470547

Effective control laws for mechanical systems are best designed by professionals who understand both the basic mechanics of the system under consideration and the control methodology being used to design the control law. This textbook blends two traditional disciplines: engineering mechanics and control engineering. Beginning with theory, the authors proceed through computation to laboratory experiment and present actual case studies to illustrate practical aerospace applications. Intended for first-year graduate students in engineering and applied science, this book will help structural dynamists and control engineers gain broad competence in mechanics and control. A solutions manual is available for professors.

关键词： Aeronautics Algorithms and Data Structures Applied Mathematics Autonomous Systems Avionics Avionics Computers Beam (Structures) Classical Mechanics Computational Fluid Dynamics Computer Networks Computer Programming and Language Computer Storage Devices computing System computing and informatics computing, Information, and Communication Control Systems Control Theory Data Science Elementary Algebra Embedded Systems Energy Energy Forms Energy Forms, Production and Conversion Feedback Control Finite Element Method Flexible and Active Structures Fluid Dynamics General Physics Geometry Functions Guidance, Navigation, and Control Systems Inverse Problems Kalman Filter Mathematical Analysis Mathematical Optimization Mechanical and Structural Vibrations Numerical Analysis Optimal Control Theory Optimization Algorithm Riccati Equations Robotics Robots Sensors Signal Processing Spacecraft Guidance and Control Structural Analysis Structural Design and Development Structural Engineering Structural Kinematics and Dynamics Structural Modeling and Simulation Structural System Structures, Design and Test Transducers Vibration Control

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