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Results for “simulation testbed”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS2007

Effects of Optical-density and Phase Dispersion of an Imperfect Band-limited Occulting Mask on the Broadband Performance of a TPF Coronagraph

Practical image-plane occulting masks required by high-contrast imaging systems such as the TPF-Coronagraph introduce phase errors into the transmitting beam., or, equivalently, diffracts the residual starlight into the area of the final image plane used for detecting exo-planets. Our group at JPL has recently proposed spatially Profiled metal masks that can be designed to have zero parasitic phase at the center wavelength of the incoming broadband light with small amounts of' 00 and phase dispersions at other wavelengths. Work is currently underway to design. fabricate and characterize such image-plane masks. In order to gain some understanding on the behaviors of these new imperfect band-limited occulting masks and clarify how such masks utilizing different metals or alloys compare with each other, we carried out some modeling and simulations on the contrast performance of the high-contrast imaging testbed (HCIT) at .JPL. In this paper we describe the details of our simulations and present our results.

integrated modeling↗
DOE OSTI2019

Exploring GlideinWMS and HTCondor scalability frontiers for an expanding CMS Global Pool

The CMS Submission Infrastructure Global Pool, built on Glidein-WMS andHTCondor, is a worldwide distributed dynamic pool responsible for the allocation of resources for all CMS computing workloads. Matching the continuously increasing demand for computing resources by CMS requires the anticipated assessment of its scalability limitations. In addition, the Global Plmust be able to expand in a more heterogeneous environment, in terms of resource provisioning (combining Grid, HPC and Cloud) and workload submissi.A dedicated testbed has been set up to simulate such conditions with the purpose of finding potential bottlenecks in the software or its configuration. This report provides a thorough description of the various scalabilitydimensions in size and complexity that are being explored for the future Global Pool, along with the analysis and solutions to the limitations proposed with the support of the GlideinWMS and HTCondor developer teams.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2025

A Comparison of Battery Charge Controller Technologies for Wave Energy Converters

Wave energy is a uniquely challenging field for electrical system designers. High peak and low average power potential with a constantly varying energy input is difficult to harness and control through conventional means. To power the blue economy, low-powered wave energy converters (WECs) need batteries for energy storage. Safely and effectively charging batteries from waves requires a charge controller to properly monitor and control voltage and current going to the battery. Currently, off-the-shelf charge controllers exist for other renewable generation such as wind, hydro, and solar. Two topologies were validated: a buck converter and a pulse width modulation (PWM) charge controller. Using an in-lab dry testbed, wave energy power inputs were simulated to properly validate the effectiveness of existing charge controller technologies, identifying the shortcomings and improvements needed to effectively harness wave energy.

battery storage↗
DOE OSTI2018

Analysis of the Impact of Installation Parameters and System Size on Bifacial Gain and Energy Yield of PV Systems

In this work, we present the combined effect of installation parameters (tilt angle, height above ground, and albedo) on the bifacial gain and energy yield of three photovoltaic (PV) system configurations: a single module, a row of five modules, and five rows of five modules utilizing RADIANCE based ray tracing model. We show that optimum tilt angle is dependent on parameters such as height, albedo, size of the system, and time of the year. For a single bifacial module installed in Albuquerque, NM, the optimum tilt angle is lowest (~5 degree) for summer solstice and highest (~65 degree) for winter solstice. For larger systems, optimum tilt angle can be up to 200 more than that for a single module system. We also show that modules in large scale systems, generate lower energy due to large shadowing areas cast by the modules on the ground. For albedo of 21 %, middle module in a large array generates up to 7% less energy than a single bifacial module. To validate our model, we utilize measured data from Sandia's fixed tilt bifacial PV testbed and compare it with our simulations. We find that due to higher non-uniformity, lower tilt angles demonstrate high normalized root mean square deviation (NRMSD) between measured and simulated values than high tilt angles.

14 SOLAR ENERGY↗
NASA NTRS1990

On-board switching and processing

Findings from NASA's space electronics division's (SED's) advanced systems studies related to future communications satellite services that will require onboard switching and processing technology are reviewed. SED's digital signal switching and processing technology program is reviewed. This program responds to specific systems technology development needs for enabling commercial development of future satellite services. The technologies include: modulators, demodulators, and forward error-correction hardware for space- and ground-based applications; onboard information switching and processing, onboard network control, and health monitoring; and cost-efficient ground terminals. The in-house systems integration, test, and evaluation (SITE) project, which includes a laboratory testbed for evaluating technology in a simulated systems environment, is reviewed.

Harrold, Joseph L.↗
NASA NTRS1990

Graphical interfaces for cooperative planning systems

Based on a cognitive task analysis of 5 airline flight crews in a simulator study, researchers have designed a testbed for studying computer aids for en route flight path planning. This testbed runs on a Mac II controlling three color monitors, and is being used to study the design of aids for both dispatchers and flight crews. Specifically, the research focuses on design concepts for developing cooperative problem-solving systems. We use en route flight planning (selecting alternate routes or destinations due to unanticipated weather, traffic, malfunctions, etc.) as the context for studying the design of such systems. Researchers are currently exploring three questions in this test environment: (1) When interacting with a flight planning aid, how does the role of the pilot influence overall system performance; (2) Can the architecture for a cooperative planning system be built around Sacerdoti's (1983) concept of an abstraction hierarchy, where the pilot can interact with the system at many different levels of detail (but where the computer aid by default handles lower level details that the pilot has chosen not to deat with); and (3) Can graphical displays and direct manipulation of these displays provide perceptual enhancements (Larkin and Simon, 1987) of the pilot's problem-solving activities. Information is given in viewgraph form.

Smith, Philip J.↗
NASA NTRS1993

Simulating Orbital Operations Of Spacecraft

Orbital Operations Simulator, OOS, computer program developed to implement mathematical models of complex outer-space vehicular systems and be "testbed" for new flight software. Has multi-vehicular-simulation capability to model on-orbit proximity and docking operations. Version 1.0, with its Prepare Processor and User Interface Shell designed to be true multivehicle dynamic simulator with capability to change mathematical models of spacecraft subsystems easily. Written in K & R standard C, LEX, and YACC languages and operates under System V shell.

Edwards, Carter↗
NASA NTRS1991

Lunar surface structural concepts and construction studies

The topics are presented in viewgraph form and include the following: lunar surface structures construction research areas; lunar crane related disciplines; shortcomings of typical mobile crane in lunar base applications; candidate crane cable suspension systems; NIST six-cable suspension crane; numerical example of natural frequency; the incorporation of two new features for improved performance of the counter-balanced actively-controlled lunar crane; lunar crane pendulum mechanics; simulation results; 1/6 scale lunar crane testbed using GE robot for global manipulation; basic deployable truss approaches; bi-pantograph elevator platform; comparison of elevator platforms; perspective of bi-pantograph beam; bi-pantograph synchronously deployable tower/beam; lunar module off-loading concept; module off-loader concept packaged; starburst deployable precision reflector; 3-ring reflector deployment scheme; cross-section of packaged starburst reflector; and focal point and thickness packaging considerations.

Mikulas, Martin↗
NASA NTRS1995

A study of space-rated connectors using a robot end-effector

The main research activities have been directed toward the study of the Robot Operated Materials Processing System (ROMPS), developed at GSFC under a flight project to investigate commercially promising in-space material processes and to design reflyable robot automated systems to be used in the above processes for low-cost operations. The research activities can be divided into two phases. Phase 1 dealt with testing of ROMPS robot mechanical interfaces and compliant device using a Stewart Platform testbed and Phase 2 with computer simulation study of the ROMPS robot control system. This report provides a summary of the results obtained in Phase 1 and Phase 2.

Nguyen, Charles C.↗
NASA NTRS1995

Mechanisms test bed math model modification and simulation support

This report summarizes the work performed under contract NAS8-38771 in support of the Marshall Space Flight Center Six Degree of Freedom Motion Facility and Flight Robotics Laboratory. The contract activities included the development of the two flexible body and Remote Manipulator System simulations, Dynamic Overhead Target Simulator control system and operating software, Global Positioning System simulation, and Manipulator Coupled Spacecraft Controls Testbed. Technical support was also provided for the Lightning Imaging Sensor and Solar X-Ray Imaging programs. The cover sheets and introductory sections for the documentation written under this contract are provided as an appendix.

Gilchrist, Andrea C.↗
NASA NTRS1997

RIACS

Topics considered include: high-performance computing; cognitive and perceptual prostheses (computational aids designed to leverage human abilities); autonomous systems. Also included: development of a 3D unstructured grid code based on a finite volume formulation and applied to the Navier-stokes equations; Cartesian grid methods for complex geometry; multigrid methods for solving elliptic problems on unstructured grids; algebraic non-overlapping domain decomposition methods for compressible fluid flow problems on unstructured meshes; numerical methods for the compressible navier-stokes equations with application to aerodynamic flows; research in aerodynamic shape optimization; S-HARP: a parallel dynamic spectral partitioner; numerical schemes for the Hamilton-Jacobi and level set equations on triangulated domains; application of high-order shock capturing schemes to direct simulation of turbulence; multicast technology; network testbeds; supercomputer consolidation project.

Oliger, Joseph↗
NASA NTRS1999

In-Space Internet-Based Communications for Space Science Platforms Using Commercial Satellite Networks

The continuing technological advances in satellite communications and global networking have resulted in commercial systems that now can potentially provide capabilities for communications with space-based science platforms. This reduces the need for expensive government owned communications infrastructures to support space science missions while simultaneously making available better service to the end users. An interactive, high data rate Internet type connection through commercial space communications networks would enable authorized researchers anywhere to control space-based experiments in near real time and obtain experimental results immediately. A space based communications network architecture consisting of satellite constellations connecting orbiting space science platforms to ground users can be developed to provide this service. The unresolved technical issues presented by this scenario are the subject of research at NASA's Glenn Research Center in Cleveland, Ohio. Assessment of network architectures, identification of required new or improved technologies, and investigation of data communications protocols are being performed through testbed and satellite experiments and laboratory simulations.

Kerczewski, Robert J.↗
NASA NTRS1999

Experimental Verification of Computational Models for Laminated Composites

The objective of the research reported herein is to develop a progressive damage methodology capable of predicting the residual strength of continuous fiber-reinforced, laminated, polymer matrix composites with through-penetration damage. The fracture behavior of center-notch tension panels with thin crack-like slits was studied. Since fibers are the major load-carrying constituent in polymer matrix composites, predicting the residual strength of a laminate requires a criterion for fiber fracture. The effects on fiber strain due to other damage mechanisms such as matrix cracking and delaminations must also be modeled. Therefore, the research herein examines the damage mechanisms involved in translaminate fracture and identifies the toughening mechanisms responsible for damage growth resistance in brittle epoxy matrix systems. The mechanics of matrix cracking and fiber fracture are discussed as is the mathematical framework for the progressive damage model developed by the authors. The progressive damage analysis algorithms have been implemented into a general purpose finite element code developed by NASA, the Computational Structural Mechanics Testbed (COMET). Damage growth is numerically simulated and the analytical residual strength predictions are compared to experimental results for a variety of notched panel configurations and materials systems.

Harris, Charles E.↗
NASA NTRS2012

HCIT Broadband Contrast Performance Sensitivity Studies

One of the important milestones of the TPF Coronagraph project is to demonstrate the ability to predict the performance sensitivities of the system at levels consistent with exo-planet detection requirement. We want to gain some general understanding about the potentials and the limitations of the current single-Deformable-Mirror (DM) High-contrast imaging testbed (HCIT) system through modeling and simulations. Specifically, we want to understand the effects of some common errors on the EFC-based control of e-field over a half dark-hole region and broadband contrast. Investigated errors include: (1) Absorbing particles on a flat-mirror (2) Defects on the Occulter surface (3) Dead actuators on the DM. We also investigated the effects of control bandwidth on the broadband contrast. We used a MACOS-based simulation algorithm which (1) combines a ray trace, diffraction model, & a broadband wavefront control algorithm (2) is capable of performing full three-dimensional near-field diffraction analysis

exoplanets↗
NASA NTRS2014

TPSAS-NF1676L-18905-DND

Aircraft loss of control is a leading cause of fatal accidents across all transport airplane and operational classes. Aircraft loss-of-control (LOC) accidents are highly complex in that they can result from numerous causal and contributing factors acting alone or (more often) in combination. Hence, there is no single intervention strategy to prevent these accidents. This presentation will define LOC as a dynamics and control problem, summarize LOC accident analysis results, and discuss current NASA research that supports a holistic approach for significantly reducing aircraft LOC accidents for current and future aircraft. The approach includes onboard systems technologies for LOC prevention and recovery, as well as a parallel effort for their validation. The onboard systems technologies provide improved situational awareness, guidance, and control under realistic LOC hazards, and include: hazards effects detection and mitigation; upset detection, prevention and recovery; and multiple hazards mitigation. Validation technologies include analytical, simulation, and experimental methods, tools and testbeds as well as the development of a comprehensive set of realistic LOC test scenarios. Future research directions will also be discussed.

Christine Belcastro↗
DOE OSTI2024

A Comparison of Battery Charge Controller Technologies for Wave Energy Converters: Preprint

Wave energy is a uniquely challenging field for electrical system designers. High peak and low average power potential with a constantly varying energy input is difficult to harness and control through conventional means. To power the blue economy, low-powered wave energy converters (WECs) need batteries for energy storage. Safely and effectively charging batteries from waves requires a charge controller to properly monitor and control voltage and current going to the battery. Currently, off-the-shelf charge controllers exist for other renewable generation such as wind, hydro, and solar. Two topologies were validated: a buck converter and a pulse width modulation (PWM) charge controller. Using an in-lab dry testbed, wave energy power inputs were simulated to properly validate the effectiveness of existing charge controller technologies, identifying the shortcomings and improvements needed to effectively harness wave energy.

battery storage↗