Download or read book Modeling and Control of Scramjet powered Hypersonic Vehicles with Aero thermo elastic propulsive Effects written by Robert John McCullen and published by . This book was released on 2008 with total page 670 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling Analysis and Control of a Hypersonic Vehicle with Significant Aero thermo elastic propulsion Interactions and Propulsive Uncertainty written by Akshay Shashikumar Korad and published by . This book was released on 2010 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis examines the modeling, analysis, and control system design issues for scramjet powered hypersonic vehicles. A nonlinear three degrees of freedom longitudinal model which includes aero-propulsion-elasticity effects was used for all analysis. This model is based upon classical compressible flow and Euler-Bernouli structural concepts. Higher fidelity computational fluid dynamics and finite elementmethods are needed formore precise intermediate and final evaluations. The methods presented within this thesis were shown to be useful for guiding initial control relevant design. The model was used to examine the vehicles static and dynamic characteristics over the vehicles trimmable region. The vehicle has significant longitudinal coupling between the fuel equivalency ratio (FER) and the flight path angle (FPA). For control system design, a two-input two-output plant (FER - elevator to speed-FPA) with 11 states (including 3 flexible modes) was used. Velocity, FPA, and pitch were assumed to be available for feedback.

Download or read book Control Relevant Design of Scramjet powered Hypersonic Vehicles with Aero thermo elastic propulsive Effects and Uncertainty written by Srikanth Sridharan and published by . This book was released on 2010 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling Analysis and Control of a Hypersonic Vehicle with Significant Aero thermo elastic propulsion Interactions written by Jaidev Khatri and published by . This book was released on 2011 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis examines themodeling, analysis, and control system design issues for scramjet powered hypersonic vehicles. A nonlinear three degrees of freedom longitudinal model which includes aero-propulsion-elasticity effects was used for all analyses. This model is based upon classical compressible flow and Euler-Bernouli structural concepts. Higher fidelity computational fluid dynamics and finite element methods are needed for more precise intermediate and final evaluations. The methods presented within this thesis were shown to be useful for guiding initial control relevant design. The model was used to examine the vehicle's static and dynamic characteristics over the vehicle's trimmable region. The vehicle has significant longitudinal coupling between the fuel equivalency ratio (FER) and the flight path angle (FPA). For control system design, a two-input two-output plant (FER - elevator to speed-FPA) with 11 states (including 3 flexible modes) was used. Velocity, FPA, and pitch were assumed to be available for feedback. Aerodynamic heat modeling and design for the assumed TPS was incorporated to original Bolender's model to study the change in static and dynamic properties. De-centralized control stability, feasibility and limitations issues were dealt with the change in TPS elasticity, mass and physical dimension. The impact of elasticity due to TPS mass, TPS physical dimension as well as prolonged heating was also analyzed to understand performance limitations of de-centralized control designed for nominal model.

Download or read book Control Relevant Modeling and Design of Scramjet powered Hypersonic Vehicles written by Jeffrey James Dickeson and published by . This book was released on 2012 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report provides an overview of scramjet-powered hypersonic vehicle modeling and control challenges. Such vehicles are characterized by unstable non-minimum phase dynamics with significant coupling and low thrust margins. Recent trends in hypersonic vehicle research are summarized. To illustrate control relevant design issues and tradeoffs, a generic nonlinear 3DOF longitudinal dynamics model capturing aero-elastic-propulsive interactions for wedge-shaped vehicle is used. Limitations of the model are discussed and numerous modifications have been made to address control relevant needs. Two different baseline configurations are examined over a two-stage to orbit ascent trajectory. The report highlights how vehicle level-flight static (trim) and dynamic properties change over the trajectory. Thermal choking constraints are imposed on control system design as a direct consequence of having a finite FER margin. The implication of this state-dependent nonlinear FER margin constraint, the right half plane (RHP) zero, and lightly damped flexible modes, on control system bandwidth (BW) and FPA tracking has been discussed. A control methodology has been proposed that addresses the above dynamics while providing some robustness to modeling uncertainty. Vehicle closure (the ability to fly a trajectory segment subject to constraints) is provided through a proposed vehicle design methodology. The design method attempts to use open loop metrics whenever possible to design the vehicle. The design method is applied to a vehicle/control law closed loop nonlinear simulation for validation. The 3DOF longitudinal modeling results are validated against a newly released NASA 6DOF code.

Download or read book Control oriented Analysis of Aerothermoelastic Effects for a Hypersonic Vehicle written by Sanketh Bhat and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: Hypersonic flight is seen as a feasible solution to make space travel faster, safer and more affordable. The design of the Air-breathing hypersonic vehicle is such that there is coupling between the structure and the propulsion system. Therefore, the aerodynamic, propulsion and the structural effects must be accounted to effectively model the vehicle. The vibrations from the structure affect the performance of the vehicle. Hence, vibration attenuation is a critical requirement for hypersonic vehicles. The problems of vibration are compounded by variations in heating during flight. Structural variations resulting from the tremendous heating incurred during hypersonic flight is mitigated by a thermal protection system (TPS); however, such mitigation is accompanied by an increase in weight that can be prohibitive. The actual design of a thermal protection system can be chosen to vary the level of heating reduction, and associated weight, across the structure.

Download or read book Aerothermoelastic Considerations for a Control Surface on an Air breathing Hypersonic Vehicle written by Benjamin R. Szpak and published by . This book was released on 2009 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Hypersonic Vehicles written by Giuseppe Pezzella and published by BoD – Books on Demand. This book was released on 2019-10-02 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the aviation field there is great interest in high-speed vehicle design. Hypersonic vehicles represent the next frontier of passenger transportation to and from space. However, several design issues must be addressed, including vehicle aerodynamics and aerothermodynamics, aeroshape design optimization, aerodynamic heating, boundary layer transition, and so on. This book contains valuable contributions focusing on hypervelocity aircraft design. Topics covered include hypersonic aircraft aerodynamic and aerothermodynamic design, especially aeroshape design optimization, computational fluid dynamics, and scramjet propulsion. The book also discusses high-speed flow issues and the challenges to achieving the dream of affordable hypersonic travel. It is hoped that the information contained herein will allow for the development of safe and efficient hypersonic vehicles.

Download or read book Selected Aerothermodynamic Design Problems of Hypersonic Flight Vehicles written by Ernst Heinrich Hirschel and published by Springer Science & Business Media. This book was released on 2009-11-26 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book An Extended Supersonic Combustion Model for the Dynamic Analysis of Hypersonic Vehicles written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-30 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of an advanced dynamic model for aeroelastic hypersonic vehicles powered by air breathing engines requires an adequate engine model. This report provides a discussion of some of the more important features of supersonic combustion and their relevance to the analysis and design of supersonic ramjet engines. Of particular interest are those aspects of combustion that impact the control of the process. Furthermore, the report summarizes efforts to enhance the aeropropulsive/aeroelastic dynamic model developed at the Aerospace Research Center of Arizona State University by focusing on combustion and improved modeling of this flow. The expanded supersonic combustor model described here has the capability to model the effects of friction, area change, and mass addition, in addition to the heat addition process. A comparison is made of the results from four cases: (1) heat addition only; (2) heat addition plus friction; (3) heat addition, friction, and area reduction, and (4) heat addition, friction, area reduction, and mass addition. The relative impact of these effects on the Mach number, static temperature, and static pressure distributions within the combustor are then shown. Finally, the effects of frozen versus equilibrium flow conditions within the exhaust plume is discussed. Bossard, J. A. and Peck, R. E. and Schmidt, D. K. Unspecified Center NAG1-1341...

Download or read book Geometry Modeling and Adaptive Control of Air breathing Hypersonic Vehicles written by Tyler J. Vick and published by . This book was released on 2014 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Active Control of Aerothermoelastic Effects for a Conceptual Hypersonic Aircraft written by and published by . This book was released on 1990 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aerothermoelastic Modeling of Hypersonic Vehicles written by Ryan Dale Jamison and published by . This book was released on 2008 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamic Interactions Between Hypersonic Vehicle Aerodynamics and Propulsion System Performance written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-24 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Described here is the development of a flexible simulation model for scramjet hypersonic propulsion systems. The primary goal is determination of sensitivity of the thrust vector and other system parameters to angle of attack changes of the vehicle. Such information is crucial in design and analysis of control system performance for hypersonic vehicles. The code is also intended to be a key element in carrying out dynamic interaction studies involving the influence of vehicle vibrations on propulsion system/control system coupling and flight stability. Simple models are employed to represent the various processes comprising the propulsion system. A method of characteristics (MOC) approach is used to solve the forebody and external nozzle flow fields. This results in a very fast computational algorithm capable of carrying out the vast number of simulation computations needed in guidance, stability, and control studies. The three-dimensional fore- and aft body (nozzle) geometry is characterized by the centerline profiles as represented by a series of coordinate points and body cross-section curvature. The engine module geometry is represented by an adjustable vertical grid to accommodate variations of the field parameters throughout the inlet and combustor. The scramjet inlet is modeled as a two-dimensional supersonic flow containing adjustable sidewall wedges and multiple fuel injection struts. The inlet geometry including the sidewall wedge angles, the number of injection struts, their sweepback relative to the vehicle reference line, and strut cross-section are user selectable. Combustion is currently represented by a Rayleigh line calculation including corrections for variable gas properties; improved models are being developed for this important element of the propulsion flow field. The program generates (1) variation of thrust magnitude and direction with angle of attack, (2) pitching moment and line of action of the thrust vector, (3) pressure and temperature d...

Download or read book Scramjet Propulsion written by E. T. Curran and published by AIAA. This book was released on 2001 with total page 1354 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Generic Hypersonic Vehicle Performance Model written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-03 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: An integrated computational model of a generic hypersonic vehicle was developed for the purpose of determining the vehicle's performance characteristics, which include the lift, drag, thrust, and moment acting on the vehicle at specified altitude, flight condition, and vehicular configuration. The lift, drag, thrust, and moment are developed for the body fixed coordinate system. These forces and moments arise from both aerodynamic and propulsive sources. SCRAMjet engine performance characteristics, such as fuel flow rate, can also be determined. The vehicle is assumed to be a lifting body with a single aerodynamic control surface. The body shape and control surface location are arbitrary and must be defined. The aerodynamics are calculated using either 2-dimensional Newtonian or modified Newtonian theory and approximate high-Mach-number Prandtl-Meyer expansion theory. Skin-friction drag was also accounted for. The skin-friction drag coefficient is a function of the freestream Mach number. The data for the skin-friction drag coefficient values were taken from NASA Technical Memorandum 102610. The modeling of the vehicle's SCRAMjet engine is based on quasi 1-dimensional gas dynamics for the engine diffuser, nozzle, and the combustor with heat addition. The engine has three variable inputs for control: the engine inlet diffuser area ratio, the total temperature rise through the combustor due to combustion of the fuel, and the engine internal expansion nozzle area ratio. The pressure distribution over the vehicle's lower aft body surface, which acts as an external nozzle, is calculated using a combination of quasi 1-dimensional gas dynamic theory and Newtonian or modified Newtonian theory. The exhaust plume shape is determined by matching the pressure inside the plume, calculated from the gas dynamic equations, with the freestream pressure, calculated from Newtonian or Modified Newtonian theory. In this manner, the pressure distribution along the vehicle after body expa...

Download or read book Output Feedback Control and Sensor Placement for a Hypersonic Vehicle Model written by Pete Jankovsky and published by . This book was released on 2006 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper addresses issues related to output feedback control, including sensor placement, for a model of an air-breathing hypersonic vehicle. The model presents a number of control challenges, in particular because of strong couplings between the propulsive and aerodynamic forces. Because of the vehicle's low weight, slenderness, and length, the vehicle's flexibility has a large impact on stability and control of the vehicle. Two output feedback control methods are developed. One applies reconstruction of the flexible body system states, toward applications of state feedback control. The other uses a robust design that does not rely on an observer to ensure stabilization and performance throughout a given flight envelope. A rate gyroscope and an accelerometer have been modeled, incorporating the flexible effects, and strategies for sensor placement have been developed for the hypersonic vehicle model to enhance observability or to preserve certain system structures that are favorable for robust control design. Simulation results are provided to demonstrate the sensor placement strategies and output feedback control performances.