Six-Degree-of-Freedom Simulation of Hypersonic Vehicles

Frendreis, Scott; Skujins, Torstens; Cesnik, Carlos E. S.

doi:10.2514/6.2009-5601

Cited by 18 publications

(18 citation statements)

References 8 publications

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“…To date, efforts have been directed almost exclusively on designing nonlinear control algorithms for longitudinal models of HSV dynamics [3]- [7], following steady progress in control-oriented modeling [8], [9]. It is only natural that the availability of 6-DOF models of hypersonic vehicle dynamics (see, for instance, [10], [11]) should prompt the development of flight control systems for this class of aircraft that address the challenges stemming from the tightly coupled, highly nonlinear and notoriously uncertain nature of HSV dynamics.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear adaptive reconfigurable controller for a generic 6-DOF hypersonic vehicle model

Serrani

Bolender

2014

2014 American Control Conference

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The development of a nonlinear adaptive controller with reconfiguration capabilities for a generic 6-DOF model of an air-breathing hypersonic vehicle is considered in this paper. The proposed controller is endowed with a modular structure (comprised of an inner-loop adaptive attitude controller, a robust nonlinear outer-loop controller and a dynamic control allocation scheme) that avoids the complexity typical of solutions based on adaptive back-stepping. An observerbased algorithm achieves decoupling between adaptation and constrained actuator dynamics. A case study is presented to illustrate the capability of the proposed methodology to deal with the simultaneous occurrence of significant model uncertainty and actuator faults.

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Section: Introductionmentioning

confidence: 99%

Nonlinear adaptive reconfigurable controller for a generic 6-DOF hypersonic vehicle model

Serrani

Bolender

2014

2014 American Control Conference

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“…In order to explore the characteristics of a three-dimensional vehicle flight, Frendreis et al 3 have conducted a full six-degree-of-freedom analysis of a generic hypersonic vehicle which included a rigid vehicle structure, twodimensional shock expansion theory for the external panel pressures, and a one-dimensional area ratio model of the propulsion system. This work was then expanded by Falkiewicz, Frendreis, and Cesnik 4 to include the effects of a flexible fuselage, flexible control surfaces, the resulting inertial coupling, unsteady aerodynamics, and aerothermal effects by partitioning the HSV into discrete component regions among which information was exchanged to maintain vehicle continuity.…”

Section: Introductionmentioning

confidence: 99%

Aerothermoelastic Simulation of Air-Breathing Hypersonic Vehicles

Klock

Cesnik

2014

55th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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This paper describes the development and implementation of a partitioned-based, multiphysics, multi-fidelity simulation framework for flexible hypersonic vehicles. This simulation framework will enable the study of the dominant physics needed for the generation of control-oriented models and will provide a reference model for flight control evaluation. A partitioned-based solution is employed to approach the problem of modeling a flexible hypersonic vehicle by dividing the vehicle into discrete regions within which unique combinations of physical processes are relevant. The dominant physics of each region are then modeled locally and information is exchanged across region interfaces at predetermined time intervals as the vehicle simulation is marched forward in time. The highly coupled physical processes within each region are modeled using an array of variable fidelity reduced order models. The partition solution implementation is compared to a monolithic solution through trim and time simulation of a sample hypersonic vehicle geometry. Trim results of rigid and flexible vehicle models show good matching between the partitioned and monolithic solutions for Mach 6, 26 km altitude, steady level flight. Time simulations at the same flight conditions also show good qualitative matching between the solutions, but a mismatch in effective mass distribution allows the monolithic vehicle model to have a slightly faster control response to a commanded elevon deflection. The partitioned solution code architecture is then extended to the characterization of flutter for a hypersonic lifting surface, showing a significant reduction of flutter Mach number as a function of flight time. I. IntroductionYPERSONIC flight presents highly coupled physical processes that must be adequately modeled in order to design the vehicle and its flight control laws. Unsteady aerodynamics, structural dynamics, aerothermal heating, thermal degradation of material properties, geometric stiffening due to thermal gradients, and thermochemical processes all play integral roles in the performance of a hypersonic vehicle (HSV). Due to these coupled and generally complex processes, the reduction of HSV states to manageable numbers has been a daunting task and posed as a significant hurdle to the timely evaluation of vehicle response and stability.Past research by Bolender and Doman 1 described a two-dimensional longitudinal flight dynamics model which employed a combination of oblique shock, Prandtl-Meyer expansion, and a quasi-one-dimensional duct with heat addition to determine the stability characteristics of a two-dimensional HSV. The inclusion of shock-expansion theory, rather than the previously studied 2 Newtonian impact theory, allowed for the consideration of engine inlet spillage and inlet shock patterns which are both considered with respect to a movable inlet door intended to maintain a shock-on-lip condition. Pressures on the aft body resulting from the propulsion exhaust are also considered. Flat plates are used to approximate control surf...

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“…This emphasizes the importance of calculating transition boundaries preflight. Many other works have discussed the flight mechanics of scramjet vehicles [3][4][5][6] including trajectory analysis [7][8][9][10] and feedback control [11,12]. Recent work has also discussed the flight dynamics of both flight modes [13] but not specifically the transition.…”

Section: Introductionmentioning

confidence: 99%

Flight Mechanics of Ram-Scram Transition

Dalle

Driscoll

2013

AIAA Atmospheric Flight Mechanics (AFM) Conference

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Among known air-breathing propulsion systems, the system that can be operated over the widest range of flight Mach numbers is the dual-mode ramjet-scramjet. In such an engine, either subsonic combustion or supersonic combustion can occur in a shared flowpath, and the mode of operation is determined by the flight condition and control inputs. Recent research has indicated that the steadystate thrust of such an engine is discontinuous across the transition from one mode to the other. This work discusses evidence for that discontinuity and discuss conditions and strategies required to maintain control through ram-scram transition. Nomenclature a = acceleration A = duct area c p = specific heat at constant pressure C L = lift coefficient C D = drag coefficient I = impulse function K = drag polar coefficient m f = cumulative fuel consumptioṅ m = mass floẇ m f = fuel mass flow rate M = Mach number p = pressure q ∞ = freestream dynamic pressure Q f = specific fuel heat release R = normalized gas constant S = reference area t = time T = temperature u = total flow speed u = vector of control variables V = velocity of vehicle x = vector of state variables γ = ratio of specific heats, flight path angle η c = combustion efficiency ρ = density τ = temporal integration variable

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Six-Degree-of-Freedom Simulation of Hypersonic Vehicles

Cited by 18 publications

References 8 publications

Nonlinear adaptive reconfigurable controller for a generic 6-DOF hypersonic vehicle model

Nonlinear adaptive reconfigurable controller for a generic 6-DOF hypersonic vehicle model

Aerothermoelastic Simulation of Air-Breathing Hypersonic Vehicles

Flight Mechanics of Ram-Scram Transition

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