[PDF] Geometry Modeling And Adaptive Control Of Air Breathing Hypersonic Vehicles eBook

Author : Tyler J. Vick
Publisher :
Page : 149 pages
File Size : 16,23 MB
Release : 2014
Category :
ISBN :

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Air-breathing hypersonic vehicles have the potential to provide global reach and affordable access to space. Recent technological advancements have made scramjet-powered flight achievable, as evidenced by the successes of the X-43A and X-51A flight test programs over the last decade. Air-breathing hypersonic vehicles present unique modeling and control challenges in large part due to the fact that scramjet propulsion systems are highly integrated into the airframe, resulting in strongly coupled and often unstable dynamics. Additionally, the extreme flight conditions and inability to test fully integrated vehicle systems larger than X-51 before flight leads to inherent uncertainty in hypersonic flight. This thesis presents a means to design vehicle geometries, simulate vehicle dynamics, and develop and analyze control systems for hypersonic vehicles. First, a software tool for generating three-dimensional watertight vehicle surface meshes from simple design parameters is developed. These surface meshes are compatible with existing vehicle analysis tools, with which databases of aerodynamic and propulsive forces and moments can be constructed. A six-degree-of-freedom nonlinear dynamics simulation model which incorporates this data is presented. Inner-loop longitudinal and lateral control systems are designed and analyzed utilizing the simulation model. The first is an output feedback proportional-integral linear controller designed using linear quadratic regulator techniques. The second is a model reference adaptive controller (MRAC) which augments this baseline linear controller with an adaptive element. The performance and robustness of each controller are analyzed through simulated time responses to angle-of-attack and bank angle commands, while various uncertainties are introduced. The MRAC architecture enables the controller to adapt in a nonlinear fashion to deviations from the desired response, allowing for improved tracking performance, stability, and robustness.

Author : Kevin P. Groves
Publisher :
Page : 0 pages
File Size : 47,10 MB
Release : 2005
Category : Hypersonic planes
ISBN :

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Seen as a possible way of making space access more affordable, air-breathing hypersonic vehicles have been studied sporadically over the last five decades as the technical advances necessary for their development were missing. New technology has brought a renewed interest in the research area, as demonstrated by the successful flights of NASA's X-43A in April and November of 2004. Air-breathing hypersonic vehicles are characterized by their unique design, incorporating a supersonic combustion ramjet engine located beneath the fuselage. This esoteric configuration results in strong coupling between the thrust and pitch dynamics of the vehicle, which in combination with flexible effects and static instability make the vehicle a challenging application for control. For a particular model of the longitudinal dynamics of an air-breathing hypersonic vehicle, a nonlinear high fidelity simulation is developed. Tables are generated which provide a static mapping of the states/inputs to the aero-dynamic forces for the purpose of creating bounds to be used in future nonlinear control development. The tables also allow the calculation of the aerodynamics forces and moments to be replaced by a table look-up with multidimensional interpolation. A linear controller is designed using a linearized model derived numerically from the nonlinear simulation about a specific trim condition. The controller is designed to track given reference commands in velocity, angle-of-attack, and altitude using a LQR technique. The gains are tuned to achieve the performance objectives without violating the input constraints. The controller is then tested on the nonlinear simulation and functions adeptly. Anti-windup control is added to allow the input constraints to be considered in the formulation of the linear controller. In doing so the gains of the linear controller can be increased without manually keeping the inputs within their constraints through tuning of the weighting matrices. This allows both the speed of the closed loop response and that of the reference trajectories to be increased, resulting in better performance.

Author : Nicholas Michael Sambaluk
Publisher : Bloomsbury Publishing USA
Page : 456 pages
File Size : 13,70 MB
Release : 2019-08-08
Category : History
ISBN :

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This reference work examines how sophisticated cyber-attacks and innovative use of social media have changed conflict in the digital realm, while new military technologies such as drones and robotic weaponry continue to have an impact on modern warfare. Cyber warfare, social media, and the latest military weapons are transforming the character of modern conflicts. This book explains how, through overview essays written by an award-winning author of military history and technology topics; in addition to more than 200 entries dealing with specific examples of digital and physical technologies, categorized by their relationship to cyber warfare, social media, and physical technology areas. Individually, these technologies are having a profound impact on modern conflicts; cumulatively, they are dynamically transforming the character of conflicts in the modern world. The book begins with a comprehensive overview essay on cyber warfare and a large section of A–Z reference entries related to this topic. The same detailed coverage is given to both social media and technology as they relate to conflict in the 21st century. Each of the three sections also includes an expansive bibliography that serves as a gateway for further research on these topics. The book ends with a detailed chronology that helps readers place all the key events in these areas.

Author : Benjamin R. Szpak
Publisher :
Page : 33 pages
File Size : 49,47 MB
Release : 2009
Category :
ISBN :

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Abstract: Air-breathing hypersonic vehicles have risen to the forefront of the aerospace research community in reaction to the requirements of NASA and the US Air Force. NASA has interest in developing a next generation Reusable Launch Vehicle and the US Air Force is interested in an unmanned hypersonic vehicle. Recent research has focused on developing comprehensive models in order to successfully design a vehicle capable of operating in the severe hypersonic environment. Due to the layout of this class of vehicle, where the propulsion system is fully integrated into the lifting body fuselage, a tight coupling exists between the airframe, propulsion system, control system, and aerodynamics. This characteristic necessitates a multi-disciplinary approach to modeling for control design. To achieve this, a simplified model of each subsystem is needed to efficiently perform a multi-disciplinary analysis. Two important and challenging areas for multi-disciplinary modeling are the incorporation of complex aerodynamic and aerothermoelastic phenomena. The focus of this research is on the development of a model for the control surface. Specifically an aerothermoelastic model, based on a plate representation, has been developed for the vehicle control surface. This model was adapted from a previous model, developed at the Air Force Research Laboratory, to incorporate important characteristics such as taper and sweep of the control surface. Thus, the model more realistically represents the geometry of a control surface for a hypersonic vehicle. The structural model developed was then verified using finite element analysis to compare the free vibration frequencies and modeshapes. Since the structural dynamic characteristics of a solid plate are not compatible to those of a shell structured wing, the structural properties were modified to match the first two frequencies of a representative wing, namely the F-104 Lockheed Starfighter wing. As the temperature of a plate increases, the first two frequencies begin to coalesce. This coalescence of frequencies leads to a phenomena known as flutter. As the temperature of the plate was increased the aerothermoelastic response was computed at a constant Mach number until the onset of flutter. By implementing a flexible control surface model, the response of the wing to control inputs and fuselage deformations could also be investigated. Both of these effects are modeled as base motion of the cantilevered plate. Second order piston theory, a commonly used model for hypersonic aerodynamics, was used to calculate the aerodynamic forces on the plate. Results presented provide insight into the importance of aerothermoelastic effects for control oriented modeling, as well as the effect of plate sweep and taper compared to a simple square plate representation.

Author : Ruizhuo Song
Publisher : Springer
Page : 271 pages
File Size : 12,50 MB
Release : 2018-12-28
Category : Technology & Engineering
ISBN : 9811317127

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This book presents a class of novel optimal control methods and games schemes based on adaptive dynamic programming techniques. For systems with one control input, the ADP-based optimal control is designed for different objectives, while for systems with multi-players, the optimal control inputs are proposed based on games. In order to verify the effectiveness of the proposed methods, the book analyzes the properties of the adaptive dynamic programming methods, including convergence of the iterative value functions and the stability of the system under the iterative control laws. Further, to substantiate the mathematical analysis, it presents various application examples, which provide reference to real-world practices.

Author : Ernst Heinrich Hirschel
Publisher : Springer Science & Business Media
Page : 512 pages
File Size : 22,92 MB
Release : 2009-11-26
Category : Technology & Engineering
ISBN : 354089974X

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In this book selected aerothermodynamic design problems in hypersonic vehicles are treated. Where applicable, it emphasizes the fact that outer surfaces of hypersonic vehicles primarily are radiation-cooled, an interdisciplinary topic with many implications.

Author : Bertin
Publisher : Springer Science & Business Media
Page : 280 pages
File Size : 44,44 MB
Release : 2012-12-06
Category : Science
ISBN : 1461203716

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These three volumes entitled Advances in Hypersonics contain the Proceedings of the Second and Third Joint US/Europe Short Course in Hypersonics which took place in Colorado Springs and Aachen. The Second Course was organized at the US Air Force Academy, USA in January 1989 and the Third Course at Aachen, Germany in October 1990. The main idea of these Courses was to present to chemists, com puter scientists, engineers, experimentalists, mathematicians, and physicists state of the art lectures in scientific and technical dis ciplines including mathematical modeling, computational methods, and experimental measurements necessary to define the aerothermo dynamic environments for space vehicles such as the US Orbiter or the European Hermes flying at hypersonic speeds. The subjects can be grouped into the following areas: Phys ical environments, configuration requirements, propulsion systems (including airbreathing systems), experimental methods for external and internal flow, theoretical and numerical methods. Since hyper sonic flight requires highly integrated systems, the Short Courses not only aimed to give in-depth analysis of hypersonic research and technology but also tried to broaden the view of attendees to give them the ability to understand the complex problem of hypersonic flight. Most of the participants in the Short Courses prepared a docu ment based on their presentation for reproduction in the three vol umes. Some authors spent considerable time and energy going well beyond their oral presentation to provide a quality assessment of the state of the art in their area of expertise as of 1989 and 1991.