Time Domain Simulation of the NASA Crew Launch Vehicle

Betts, Kevin; Rutherford, R.; McDuffie, James; Johnson, Matthew D.; Jackson, Mark; Hall, Charles E.

doi:10.2514/6.2007-6621

Cited by 13 publications

(10 citation statements)

References 1 publication

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“…The CLV model employed in this study is called Savant with was developed in a joint effort between bD Systems and NASA Marshall. The model is described in Betts 8 and itt contains simulated rigid body, aerodynamics, gravity, sloshing, engine inertia effect, mass change, actuator, and elastic body models. Many of these effects can be turned on or off in the simulation environment.…”

Section: Iia CLV Model Descriptionmentioning

confidence: 99%

“…If it can be shown that x orx is bounded, then the emulation error can be shown to converge asymptotically for perfect parameterization. Since the emulator tracking error dynamics (8) are BIBO, this error remains bounded as long as the linear control law ensures that the system state does not go unbounded. If for some reason it is determined that the system tracking error is too large, one can then apply adaptive control to the system.…”

Section: Iiia State Feedback Control Lawmentioning

confidence: 99%

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Limited Adaptive Authority Flight Control for the Crew Launch Vehicle

Muse

Calise

2009

AIAA Guidance, Navigation, and Control Conference

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The control system of the NASA Crew Launch Vehicle is designed to meet performance and robustness requirements during its ascent flight phase. However, the controller bandwidth and the attainable level of robust performance is limited by the degree of flexibility inherent in the long and slender design that has been adopted for this vehicle. Since there remains a substantial degree of uncertainty regarding the structural dynamics of this vehicle, the degree of risk associated with flight control is reduced by permitting a greater level of robust performance to be attained by augmenting the existing flight control system design with an adaptive element to recover nominal performance in the event of severe performance degradation. Attitude stabilization and flexible mode suppression of the model can be achieved by using a model reference adaptive controller designed to maintain the design level of tracking performance in the presence of disturbances, parametric uncertainties and unmodeled dynamics. The control law developed in this paper employs a limited authority adaptive element based on a new Virtual Hedging concept that augments an existing linear control law. The adaptation process is separate from the realization of the adaptive control decision. This guarantees a stable adaption process by employing a state emulator. It allows the system uncertainty to be learned online without applying any additional control. This is critical for implementing an adaptive control law as an emergency backup control law since the adaptive element will be engaged when the system performance is already poor. Initial errors between the system and the reference model, once the adaptive control is engaged, decays as the free response of the reference model (to within the ultimate bound). The adaptive design is carried out in both state feedback and output feedback form. Simulation examples illustrate the viability of the method.

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Section: Iia CLV Model Descriptionmentioning

confidence: 99%

Section: Iiia State Feedback Control Lawmentioning

confidence: 99%

Limited Adaptive Authority Flight Control for the Crew Launch Vehicle

Muse

Calise

2009

AIAA Guidance, Navigation, and Control Conference

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“…5) Historically, analytical theories have met with mixed success in estimating the effects of lateral sloshing liquid in a moving Ó 2009 The Japan Society for Aeronautical and Space Sciences container, especially, the theory of sloshing equivalent mechanics. [6][7][8] In general, the exact formulation and solution for propellant sloshing dynamic behavior is complex. However, according to theory, a discrete mechanical model, such as a pendulum or rigid mass series with a spring and dashpot, can represent the effects of propellant sloshing in various vessels.…”

Section: )mentioning

confidence: 99%

Dynamic Influence of Propellant Sloshing Estimation Using Hybrid: Mechanical Analogy and CFD

Dong

Wang

et al. 2009

Trans. Japan Soc. Aero. S Sci.

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Liquid propellant sloshing, which induces perturbations to dynamic behavior of spacecraft, is a serious problem. This paper proposes an approach based on equivalent mechanics theory and Computational Fluid Dynamics (CFD) technology to estimate the dynamic influence of propellant sloshing on spacecraft. A mechanical model was built by CFD technique and packed as a ''sloshing'' block utilized in the spacecraft Guidance Navigation and Control (GNC) simulation loop. The block takes the motion characteristics of the spacecraft as inputs and outputs perturbative force and torques induced by propellant sloshing. It is more convenient to utilize in analysis of the coupling effect between propellant sloshing dynamics and spacecraft GNC than CFD packages directly. A validation case is taken to validate the accuracy and the superiority of the approach. The deducing process is applied to practical cases, and the simulation results are presented to demonstrate the proposed approach is efficient in identifying the problems induced by sloshing and evaluating effectiveness of several typical schemes for suppressing sloshing.

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“…As an example of a commercial simulation tool, the company Astos Solutions has been developing the AeroSpace Trajectory Optimization Software (ASTOS®), a modularized software capable of performing trajectory simulation and optimization of launch vehicles (Cremaschi et al, 2010). Finally, in the work of Betts et al (2007), it can be found an example of a simulator constructed using the modularized characteristic of Simulink®, which facilitates modifications of the vehicle model as necessary.…”

Section: Introductionmentioning

confidence: 99%

A Six Degrees-of-Freedom Flight Dynamics Simulation Tool of Launch Vehicles

Silveira

Carrara

2015

J.Aerosp. Technol. Manag.

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ABSTRACT:The use of digital simulation has become an essential activity during the development and operation of launch vehicles, due to the complexity of such systems. Of particular interest is the flight dynamics simulation, which investigates the behavior of the vehicle in flight subjected to forces and moments. This work presents a simulation tool suited to perform six degrees-of-freedom flight dynamics investigations of launch vehicles. Developed at the Instituto Nacional de Pesquisas Espaciais (INPE) and the Instituto de Aeronáutica e Espaço (IAE) in Brazil, the tool was implemented following the requirement for flexibility, so that it can be used to simulate different types of launch vehicles. The assessment of the vehicle performance and the vehicle payload capacity are some examples of analysis that can be performed with the tool. A modular programming strategy was employed to assure the tool flexibility. Therefore, the models presented in the tool were implemented as separate modules. The combination of these models can originate flight models of different launch vehicles. Two flight scenarios of Brazilian rockets were simulated and the results were verified against simulation tools already employed by aerospace community. The developed tool showed good agreement with respect to the simulators used to perform the comparison.

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Time Domain Simulation of the NASA Crew Launch Vehicle

Cited by 13 publications

References 1 publication

Limited Adaptive Authority Flight Control for the Crew Launch Vehicle

Limited Adaptive Authority Flight Control for the Crew Launch Vehicle

Dynamic Influence of Propellant Sloshing Estimation Using Hybrid: Mechanical Analogy and CFD

A Six Degrees-of-Freedom Flight Dynamics Simulation Tool of Launch Vehicles

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