Intelligent Autonomous Decision-Making and Cooperative Control Technology of High-Speed Vehicle Swarms

This book is a reprint of the Special Issue “Intelligent Autonomous Decision-Making and Cooperative Control Technology of High-Speed Vehicle Swarms”,which was published in Applied Sciences

Aeronautical engineering: A continuing bibliography with indexes (supplement 272)

This bibliography lists 719 reports, articles, and other documents introduced into the NASA scientific and technical information system in November, 1991. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment, and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Adaptive control of a generic hypersonic vehicle

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 111-115).This thesis presents a an adaptive augmented, gain-scheduled baseline LQR-PI controller applied to the Road Runner six-degree-of-freedom generic hypersonic vehicle model. Uncertainty in control effectiveness, longitudinal center of gravity location, and aerodynamic coefficients are introduced in the model, as well as sensor bias and noise, and input time delays. The performance of the baseline controller is compared to the same design augmented with one of two different model-reference adaptive controllers: a classical open-loop reference model design, and modified closed-loop reference model design. Both adaptive controllers show improved command tracking and stability over the baseline controller when subject to these uncertainties. The closed-loop reference model controller offers the best performance, tolerating a reduced control effectiveness of 50%, rearward center of gravity shift of -0.9 to -1.6 feet (6-11% of vehicle length), aerodynamic coefficient uncertainty scaled 4x the nominal value, and sensor bias of +1.6 degrees on sideslip angle measurement. The closed-loop reference model adaptive controller maintains at least 73% of the delay margin provided by the robust baseline design, tolerating input time delays of between 18-46 ms during 3 degree angle of attack doublet, and 80 degree roll step commands.by Daniel Philip Wiese.S.M

Aerocapture, Entry, and Co-Delivery in Uncertain Planetary Atmospheres

Aerocapture, the method of entering orbit via a single pass through the atmosphere of a planet, is an enhancing or enabling technology for a range of interplanetary missions. Compared to propulsive maneuvers, aerocapture can reduce cruise duration while decreasing the total mass expended for orbit insertion, thus leaving more time and mass for the primary science mission. Two mission classes in particular both benefit from aerocapture and are of high priority for the next decade of planetary science: exploration of the ice giants, Uranus and Neptune, and low-cost small satellite platforms. However, despite its potential benefits, aerocapture has never been implemented in flight. This is primarily because of the large uncertainties involved, which must be modeled and adequately mitigated by closed-loop autonomous guidance onboard the spacecraft. Aerocapture guidance has been well-studied for vehicles that control their atmospheric flight by changing the orientation of a lift vector, but is not as well developed for a class of flight vehicles that achieve control by releasing a drag device mid-flight. Known as drag modulation, this control mechanism is significantly less complex in terms of hardware and avionics than lift modulation, and is thus appealing for small satellite missions. However, the state of the art guidance solutions have a computational demand that is both high and difficult to bound. This dissertation contributes a novel guidance algorithm for drag-modulated aerocapture that achieves equivalent performance to the state of the art, but with reduced computational demand. One of the most pernicious sources of uncertainty that aerocapture guidance must mitigate is atmospheric density, which varies over space and time. While scientific and engineering atmosphere models are available and well-characterized for on-the-ground studies, models that retain this fidelity while being significantly more compact and analytically tractable are desirable for onboard use. This dissertation develops reduced-dimensionality models of uncertain atmosphere for use onboard a spacecraft, derives a method for updating the model based on noisy measurements, and demonstrates the ability to accurately predict future state uncertainty resulting from these environmental dispersions without requiring the use of random sampling. These contributions have a range of potential applications, including incorporation into future stochastic guidance algorithms. Many of the mission concepts most relevant to aerocapture, such as the Uranus Orbiter and Probe, involve more than one flight vehicle. These missions benefit from the ability to deliver both spacecraft to their destination with minimal disruption to the overall concept of operations. While a number of missions have successfully executed multi-vehicle architectures in the past, this "co-delivery'' method has not received dedicated systematic attention. This dissertation addresses the concept as a topic in its own right, investigating the ability to co-deliver an orbiter and probe from a single approach trajectory without the need for a divert maneuver. Co-delivery of an entire network of probes from a single, non-maneuvering mothership is also investigated. Finally, expressions for relative motion in the velocity frame are derived in order to provide a mathematical model that is more intuitive than the typical rotating orbit frame for highly-elliptical orbits, as are common for aerobraking, entry, and aerocapture. To illustrate the unifying motivation for this work, the contributions of this dissertation are applied to an example problem: the concept of reducing atmospheric uncertainty for aerocapture by including a fly-ahead probe that enters the atmosphere some time before the orbiter. While this idea has been proposed several times, the benefit conferred to the orbiter by the probe has not been quantified. The contributions of this dissertation naturally lend themselves to addressing this problem, as well as other entry, aerocapture, and co-delivery scenarios for future interplanetary missions.</p

Aeronautical engineering: A continuing bibliography with indexes (supplement 247)

This bibliography lists 437 reports, articles, and other documents introduced into the NASA scientific and technical information system in December, 1989. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

A generalized framework for robust nonlinear compensation (application to an atmospheric reentry control problem)

Ce travail de thèse est consacré à l'extension de l'Inversion Dynamique non-linéaire (NDI-Nonlinear Dynamic Inversion) pour un ensemble plus grand de systèmes non-linéaires, tout en garantissant des conditions de stabilité suffisantes. La NDI a été étudiée dans le cas de diverses applications, y compris en aéronautique et en aérospatiale. Elle permet de calculer des lois de contrôle capables de linéariser et de découpler un modèle non-linéaire à tout point de fonctionnement de son enveloppe d'état. Cependant cette méthode est intrinsèquement non-robuste aux erreurs de modélisation et aux saturations en entrée. En outre, dans un contexte non-linéaire, l'obtention d'une garantie quantifiable du domaine de stabilité atteint reste à l'heure actuelle complexe. Contrairement aux approches classiques de la NDI, notre méthodologie peut être considérée comme un cadre de compensation non-linéaire généralisé qui permet d'intégrer les incertitudes et les saturations en entrée dans le processus de conception. En utilisant des stratégies de contrôle antiwindup, la loi de pilotage peut être calculée grâce à un simple processus en deux phases. Dans ce cadre de travail généralisé des transformations linéaires fractionnaires (LFT - Linear Fractional Transformations) de la boucle fermée non-linéaire peuvent être facilement déduites pour l'analyse de la stabilité robuste en utilisant des outils standards pour de systèmes linéaires. La méthode proposée est testée pour le pilotage d'un véhicule de rentrée atmosphérique de type aile delta lors de ses phases hypersonique, transsonique et subsonique. Pour cette thèse, un simulateur du vol incluant divers facteurs externes ainsi que des erreurs de modélisation a été développé dans Simulink.This thesis work is devoted to extending Nonlinear Dynamic Inversion (NDI) for a large scale of nonlinear systems while guaranteeing sufficient stability conditions. NDI has been studied in a wide range of applications, including aeronautics and aerospace. It allows to compute nonlinear control laws able to decouple and linearize a model at any operating point of its state envelope. However, this method is inherently non-robust to modelling errors and input saturations. Moreover, obtaining a quantifiable guarantee of the attained stability domain in a nonlinear control context is not a very straightforward task. Unlike standard NDI approaches, our methodology can be viewed as a generalized nonlinear compensation framework which allows to incorporate uncertainties and input saturations in the design process. Paralleling anti-windup strategies, the controller can be computed through a single multichannel optimization problem or through a simple two-step process. Within this framework, linear fractional transformations of the nonlinear closed-loop can be easily derived for robust stability analysis using standard tools for linear systems. The proposed method is tested for the flight control of a delta wing type reentry vehicle at hypersonic, transonic and subsonic phases of the atmospheric reentry. For this thesis work, a Flight Mechanics simulator including diverse external factors and modelling errors was developed in Simulink.TOULOUSE-ISAE (315552318) / SudocSudocFranceF

Aeronautical engineering: A continuing bibliography with indexes (supplement 286)

This bibliography lists 845 reports, articles, and other documents introduced into the NASA scientific and technical information system in Dec. 1992. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment, and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Aeronautical engineering: A continuing bibliography with indexes (supplement 227)

This bibliography lists 418 reports, articles, and other documents introduced into the NASA scientific and technical information system in May, 1988