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Modelling Simulation And Control Design Of An Air Breathing Hypersonic Vehicle
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Book Synopsis Modelling, Simulation, and Control Design of an Air-breathing Hypersonic Vehicle by : Kevin P. Groves
Download or read book Modelling, Simulation, and Control Design of an Air-breathing Hypersonic Vehicle written by Kevin P. Groves and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Control Oriented Modelling and Nonlinear Control Design for an Air-breathing Hypersonic Vehicle by : Jason Terry Parker
Download or read book Control Oriented Modelling and Nonlinear Control Design for an Air-breathing Hypersonic Vehicle written by Jason Terry Parker and published by . This book was released on 2006 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This thesis describes control oriented modelling, i.e. the development of a model which is amenable to control design, of an air-breathing hypersonic vehicle and nonlinear control design based on the constructed model. The full simulation model, or truth model, includes intricate couplings between the engine dynamics and the flight dynamics, along with complex interplay between the flexible and rigid modes of the vehicle. Furthermore, this model is found to be unstable and non-minimum phase with respect to the variables to be controlled. By replacing the complex force and moment functions with curve fitted approximations, neglecting certain weaker couplings, resorting to dynamic extension at the input side, and neglecting slower portions of the system dynamics, a control oriented model with full vector relative degree with respect to the regulated output is obtained. Standard dynamic inversion can then be applied to this model, resulting in approximate linearization of the input/output map of the truth model. A robust outer loop control is then designed using LQR with integral augmentation in a model reference scheme. Simulation results demonstrate that this technique achieves excellent tracking performance even in the presence of small plant parameter variations. The fidelity of the truth model is then increased by including additional flexible effects which render the original control design ineffective. A more elaborate control approach with an additional actuator is then employed to compensate for these new flexible effects, and simulation results which include mild plant parameter variations are presented.
Book Synopsis Control-oriented Modeling and Output Feedback Control of Hypersonic Air-breathing Vehicles by : David Orn Sigthorsson
Download or read book Control-oriented Modeling and Output Feedback Control of Hypersonic Air-breathing Vehicles written by David Orn Sigthorsson and published by . This book was released on 2008 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Hypersonic air-breathing vehicles are a promising and cost-efficient technology for launching low-earth-orbit satellites and providing rapid global-response capabilities. Modeling and control of such vehicles has been an active subject of research in recent years. A first-principle, physics-based model (FPM) of the vehicle's longitudinal dynamics has been developed at the Air Force Research Laboratory, and made available to the academic community for control systems design. This model, while suitable for simulation, is intractable for model-based control, thus requiring further control-oriented modeling. A typical control objective is to track a velocity and altitude reference while maintaining physical feasibility of the control input and the state. Two control strategies are presented in this work. The first is a linear time invariant (LTI) design based on a novel formulation of a robust servo-mechanism using singular perturbation arguments. This approach does not rely on state reconstruction but does require an analysis of a family of linearized models from the FPM. The second design relies on reduced-complexity modeling of the FPM. Intractable expressions of the forces and moment in the FPM are replaced with a curve-fit model (CFM). The CFM is expressed as a linear parameter varying (LPV) system, where the scheduling variables depend on the system output. A novel LPV regulator design methodology is developed, which explicitly addresses the case of over-actuated models (i.e., models with more inputs than performance outputs). This is a non-trivial extension of the analysis and design of output regulators for LTI systems. The LPV regulator separates the control problem into a steady-state controller and a stabilizing controller. The steady-state controller produces a non-unique approximate steady-state using receding horizon constrained optimization, while the stabilizer renders the steady-state attractive. The steady-state controller represents an approach to addressing over-actuated LPV systems, alternative to static or dynamic control allocation, or standard optimal control. The stabilizer design utilizes the LPV separation principle to decompose the problem into state feedback and LPV reduced order observer design. Both approaches are applied to the FPM in simulation and their merits and drawbacks discussed.
Book Synopsis Reference Command Tracking for a Linearized Model of an Air-Breathing Hypersonic Vehicle by :
Download or read book Reference Command Tracking for a Linearized Model of an Air-Breathing Hypersonic Vehicle written by and published by . This book was released on 2005 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: The focus of this paper is on control design and simulation for an air-breathing hypersonic vehicle. The challenges for control design in this class of vehicles lie in the inherent coupling between the propulsion system, and the airframe dynamics, and the presence of strong flexibility effects. Working from a highly nonlinear, dynamically-coupled simulation model, control designs are presented for velocity, angle-of-attack, and altitude command input tracking for a linearized version of a generic air-breathing hypersonic vehicle model linearized about a specific trim condition. Control inputs for this study include elevator deflection, total temperature change across the combustor, and the diffuser area ratio. Two control design methods are presented, both using linear quadratic techniques with integral augmentation, and are implemented in tracking control studies. The first approach focuses on set point tracking control, whereas in the second, a regulator design approach is taken. The effectiveness of each control design is demonstrated in simulation on the full nonlinear model of the generic vehicle.
Book Synopsis Geometry Modeling and Adaptive Control of Air-breathing Hypersonic Vehicles by : Tyler J. Vick
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.
Book Synopsis Anti-Windup Control for an Air-Breathing Hypersonic Vehicle Model by :
Download or read book Anti-Windup Control for an Air-Breathing Hypersonic Vehicle Model written by and published by . This book was released on 2005 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: An anti-windup controller modification is implemented in control system design for a model of the longitudinal dynamics of an air-breathing hypersonic vehicle. Anti-windup control allows the input constraints to be considered explicitly in the design of linear controllers to track a reference trajectory for the vehicle velocity, altitude, and angle of attack. The presence of anti-windup alleviates the need of keeping large penalties on the magnitude of the control input to avoid the occurrence of saturation. This, in turn, allows tighter tuning of the controller gains to obtain faster and more accurate trajectory tracking. The paper employs recent developments in anti-windup design to deal with the presence of exponentially unstable dynamics, which are typically encountered in air-breathing vehicle models. Simulation results on a fully nonlinear model are presented to validate the controller design.
Book Synopsis Modeling and Nonlinear Control of a 6-DOF Hypersonic Vehicle by : Mohammad Shakiba-Herfeh
Download or read book Modeling and Nonlinear Control of a 6-DOF Hypersonic Vehicle written by Mohammad Shakiba-Herfeh and published by . This book was released on 2015 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past two decades, there has been a renewed and sustained effort devoted to modeling the dynamics of air-breathing hypersonic vehicles, for both simulation and control design purposes. The highly nonlinear characteristics of flight dynamics in hypersonic regimes and the consequent significance variability of the response with the operating conditions requires the development of innovative flight control solutions, hence the development of suitable model of the vehicle dynamics that are amenable to design, validation and rapid calibration of control algorithms. In this dissertation, a control-oriented and a simulation model of a generic hypersonic vehicle were derived to support the design and calibration of model-based flight controllers. A nonlinear robust adaptive controller was developed on the basis of the control-oriented model, that was shown to provide stable trajectory tracking in higher fidelity computer simulations. The first stage of this research was the development of a control design model (CDM) for the 6-degree-of-freedom dynamics of an air-breathing hypersonic aircraft based on an available high-fidelity first principle model. A method that incorporates the theory of compressible fluid dynamics and system identification methods, was proposed and implemented. The development of the CDM is based on curve fit approximation of the forces and moments acting on the vehicle, making the model suitable for control design. Kriging and Least Squares methods were used to find the most appropriate curve-fitted model of the aerodynamic forces for both the control design and the control simulation models. It was shown that the 6-DOF model can be both categorized as an under-actuated mechanical system, as well as an over-actuated system with respect to a chosen in- put/output pair of interest. An important contribution of this work is the development of a nonlinear adaptive controller for the 6-DOF control design model. The controller was endowed with a modular structure, comprised of an adaptive inner-loop attitude controller and a robust nonlinear outer-loop controller of fixed structure. The purpose of the outer- loop controller is to avoid the typical complexity of solutions derived from adaptive backstepping methods. A noticeable feature of the outer-loop controller is the presence of an internal model unit that generates the reference for the angle-of-attack, in spite of parametric model uncertainty. Airspeed, lateral velocity, vehicle's heading and altitude were considered as regulated outputs of the system. Simulation results on the control simulation model show the effectiveness of the developed controller in spite of significant variation in the flight parameters.
Book Synopsis Nonlinear Robust/adaptive Controller Design for an Air-breathing Hypersonic Vehicle Model by : Lisa Fiorentini
Download or read book Nonlinear Robust/adaptive Controller Design for an Air-breathing Hypersonic Vehicle Model written by Lisa Fiorentini and published by . This book was released on 2007 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This thesis presents the design of two nonlinear robust controllers for an air-breathing hypersonic vehicle model. To overcome the analytical intractability of a dynamical model derived from first principles, a simplified control-oriented model is used for control design. The control-oriented model retains most of the features of the original model, including non-minimum phase characteristic of the flight-path angle dynamics and strong couplings between the engine and flight dynamics, whereas flexibility effects, included in the simulation model, are regarded as a dynamic perturbation. In adopting reduced-complexity models for controller design, the issue of robustness with respect to model uncertainty must be carefully addressed and included at the design level. Dynamic inversion-based design methods do not lend themselves easily to quantitative robustness analysis, due to the complexity of the inverse model of the plant. In this work, a nonlinear sequential loop-closure approach is adopted to design two different dynamic state-feedback controllers that provide stable tracking of velocity and altitude reference trajectories. The approach considered utilizes a combination of adaptive and robust design methods based on both classical and recently developed nonlinear design tools. Simulation results indicate that the proposed methodology may constitute a feasible approach towards the development of robust nonlinear controllers that satisfactorily address the issue of model uncertainty for this type of application.
Book Synopsis Control Design for a Non-minimum Phase Hypersonic Vehicle Model by : Thomas McKenna
Download or read book Control Design for a Non-minimum Phase Hypersonic Vehicle Model written by Thomas McKenna and published by . This book was released on 2016 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: Air-breathing hypersonic vehicles are emerging as a method for cost-efficient access to space. Great strides have recently been made in the field of hypersonic vehicles, however the unique dynamics of the vehicles present challenges for control design. In this thesis, a nonlinear controller for a hypersonic vehicle model is designed using the Indirect Manifold Construction approach. The high fidelity hypersonic vehicle model considered in this thesis includes many of the challenging effects of hypersonic flight. The main challenge to control design is the vehicle's unstable internal dynamics. This non-minimum phase behavior prevents the use of many standard forms of nonlinear control techniques. The nonlinear controller developed in this thesis following the Indirect Manifold Construction approach uses a hierarchical control design to force outputs to commanded values while ensuring the internal dynamics of the system remain stable. The nonlinear controller is shown to be effective in simulation. The closed loop system is also shown to be stable through a Lyapunov based stability analysis.
Book Synopsis Adres van den Raad van Leyden aan ʹt Provinciaal Bestuur van Holland over de jurisdictie van Rector en Rechteren van ʹs Lands Universiteit .... by :
Download or read book Adres van den Raad van Leyden aan ʹt Provinciaal Bestuur van Holland over de jurisdictie van Rector en Rechteren van ʹs Lands Universiteit .... written by and published by . This book was released on 1797 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Nonlinear Adaptive Controller Design for Air-breathing Hypersonic Vehicles by : Lisa Fiorentini
Download or read book Nonlinear Adaptive Controller Design for Air-breathing Hypersonic Vehicles written by Lisa Fiorentini and published by . This book was released on 2010 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This dissertation presents the design of two nonlinear robust controllers for an air-breathing hypersonic vehicle model capable of providing stable tracking of velocity and altitude (or flight-path angle) reference trajectories. To overcome the analytical intractability of a dynamical model derived from first principles, a simplified control-oriented model is used for control design. The control-oriented model retains the most important features of the model from which it was derived, including the non-minimum phase characteristic of the flight-path angle dynamics and strong couplings between the engine and flight dynamics. The first control design considers as control inputs the fuel equivalence ratio and the elevator and canard deflections. A combination of nonlinear sequential loop-closure and adaptive dynamic inversion has been adopted for the design of a dynamic state-feedback controller. An important contribution given by this work is the complete characterization of the internal dynamics of the model has been derived for Lyapunov-based stability analysis of the closed-loop system, which includes the structural dynamics. The results obtained address the issue of stability robustness with respect to both parametric model uncertainty, which naturally arises in adopting reduced-complexity models for control design, and dynamic perturbations due to the flexible dynamics. In the second control design a first step has been taken in extending those results in the case in which only two control inputs are available, namely the fuel equivalence ratio and the elevator deflection. The extension of these results to this new framework is not trivial since several issues arise. First of all, the vehicle dynamics are characterized by exponentially unstable zero-dynamics when longitudinal velocity and flight-path angle are selected as regulated output. This non-minimum phase behavior arises as a consequence of elevator-to-lift coupling. In the previous design the canard was strategically used to adaptively decouple lift from elevator command, thus rendering the system minimum phase. Moreover, the canard input was also employed to enforce the equilibrium at the desired trim condition and to provide a supplementary stabilizing action. As a result, when this control input is not assumed to be available, the fact that the system needs to be augmented with an integrator (to reconstruct the desired equilibrium) and the non-minimum phase behavior have a strong impact on the control design. In these preliminary results the flexible effects are not taken into account in the stability analysis but are considered as a perturbation and included in the simulation model. The approach considered utilizes a combination of adaptive and robust design methods based on both classical and recently developed nonlinear design tools. As a result, the issue of robustness with respect to parameter uncertainties is addressed also in this control design. Simulation results on the full nonlinear model show the effectiveness of both controllers.
Book Synopsis Control Relevant Modeling and Design of Scramjet-powered Hypersonic Vehicles by : Jeffrey James Dickeson
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.
Book Synopsis Approximate Feedback Linearization of an Air-Breathing Hypersonic Vehicle (PREPRINT). by :
Download or read book Approximate Feedback Linearization of an Air-Breathing Hypersonic Vehicle (PREPRINT). written by and published by . This book was released on 2005 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper describes the design of a nonlinear control law for an air-breathing hypersonic vehicle. The model of interest includes flexibility effects and intricate couplings between the engine dynamics and flight dynamics. To overcome the analytical intractability of this model, a nominal control-oriented model is constructed for the purpose of feedback control design. Analysis performed on the nominal model reveals the presence of unstable zero dynamics with respect to the output to be controlled, namely altitude and velocity. By neglecting certain weaker couplings and resorting to dynamic extension at the input side, a simplified nominal model with full vector relative degree with respect to the regulated output is obtained. Standard dynamic inversion can then be applied to the simplified nominal model, and this results in approximate linearization of the nominal model. Finally, a robust outer loop control is designed using LQR with integral augmentation in a model reference scheme. Simulation results are provided to demonstrate that the approximate feedback linearization approach achieves excellent tracking performance on the truth model for two choices of the system output. Finally, a brief case study is presented to qualitatively demonstrate the robustness of the design to parameter variations.
Author :National Aeronautics and Space Adm Nasa Publisher :Independently Published ISBN 13 :9781731319258 Total Pages :150 pages Book Rating :4.3/5 (192 download)
Book Synopsis Hypersonic Vehicle Simulation Model: Winged-Cone Configuration by : National Aeronautics and Space Adm Nasa
Download or read book Hypersonic Vehicle Simulation Model: Winged-Cone Configuration written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-11-18 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerodynamic, propulsion, and mass models for a generic, horizontal-takeoff, single-stage-to-orbit (SSTO) configuration are presented which are suitable for use in point mass as well as batch and real-time six degree-of-freedom simulations. The simulations can be used to investigate ascent performance issues and to allow research, refinement, and evaluation of integrated guidance/flight/propulsion/thermal control systems, design concepts, and methodologies for SSTO missions. Aerodynamic force and moment coefficients are given as functions of angle of attack, Mach number, and control surface deflections. The model data were estimated by using a subsonic/supersonic panel code and a hypersonic local surface inclination code. Thrust coefficient and engine specific impulse were estimated using a two-dimensional forebody, inlet, nozzle code and a one-dimensional combustor code and are given as functions of Mach number, dynamic pressure, and fuel equivalence ratio. Rigid-body mass moments of inertia and center of gravity location are functions of vehicle weight which is in turn a function of fuel flow. Shaughnessy, John D. and Pinckney, S. Zane and Mcminn, John D. and Cruz, Christopher I. and Kelley, Marie-Louise Langley Research Center AERODYNAMIC CHARACTERISTICS; AERODYNAMIC FORCES; ASCENT TRAJECTORIES; COMPUTERIZED SIMULATION; CONTROL SYSTEMS DESIGN; FORCE DISTRIBUTION; HYPERSONIC VEHICLES; MATHEMATICAL MODELS; MOMENT DISTRIBUTION; PANEL METHOD (FLUID DYNAMICS); AERODYNAMIC COEFFICIENTS; ANGLE OF ATTACK; CENTER OF GRAVITY; DEGREES OF FREEDOM; DYNAMIC PRESSURE; HYPERSONICS; MACH NUMBER; MOMENTS OF INERTIA; PROPULSION; SPECIFIC IMPULSE...
Author :Ernst Heinrich Hirschel Publisher :Springer Science & Business Media ISBN 13 :354089974X Total Pages :512 pages Book Rating :4.5/5 (48 download)
Book Synopsis Selected Aerothermodynamic Design Problems of Hypersonic Flight Vehicles by : Ernst Heinrich Hirschel
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.
Book Synopsis Air-breathing Hypersonic Vehicle Guidance and Control Studies; An Integrated Trajectory/control Analysis Methodology: Phase 1 by :
Download or read book Air-breathing Hypersonic Vehicle Guidance and Control Studies; An Integrated Trajectory/control Analysis Methodology: Phase 1 written by and published by . This book was released on 1991 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Aerothermoelastic Considerations for a Control Surface on an Air-breathing Hypersonic Vehicle by : Benjamin R. Szpak
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.
