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At least 1,045 records · Page 58
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Automated path planning of the Payload Inspection and Processing System

The Payload Changeout Room Inspection and Processing System (PIPS) is a highly redundant manipulator intended for performing tasks in the crowded and sensitive environment of the Space Shuttle Orbiter payload bay. Its dexterity will be exploited to maneuver the end effector in a workspace populated with obstacles. A method is described by which the end effector of a highly redundant manipulator is directed toward a target via a Lyapunov stability function. A cost function is constructed which represents the distance from the manipulator links to obstacles. Obstacles are avoided by causing the vector of joint parameters to move orthogonally to the gradient of the workspace cost function. A C language program implements the algorithm to generate a joint history. The resulting motion is graphically displayed using the Interactive Graphical Robot Instruction Program (IGRIP) produced by Deneb Robotics. The graphical simulation has the potential to be a useful tool in path planning for the PIPS in the Shuttle Payload Bay environment.

Byers, Robert M.↗
NASA NTRS1994

A 500 megabyte/second disk array

Applications at the Army High Performance Computing Research Center's (AHPCRC) Graphic and Visualization Laboratory (GVL) at the University of Minnesota require a tremendous amount of I/O bandwidth and this appetite for data is growing. Silicon Graphics workstations are used to perform the post-processing, visualization, and animation of multi-terabyte size datasets produced by scientific simulations performed of AHPCRC supercomputers. The M.A.X. (Maximum Achievable Xfer) was designed to find the maximum achievable I/O performance of the Silicon Graphics CHALLENGE/Onyx-class machines that run these applications. Running a fully configured Onyx machine with 12-150MHz R4400 processors, 512MB of 8-way interleaved memory, 31 fast/wide SCSI-2 channel each with a Ciprico disk array controller we were able to achieve a maximum sustained transfer rate of 509.8 megabytes per second. However, after analyzing the results it became clear that the true maximum transfer rate is somewhat beyond this figure and we will need to do further testing with more disk array controllers in order to find the true maximum.

Ruwart, Thomas M.↗
NASA NTRS1995

Applying AI tools to operational space environmental analysis

The U.S. Air Force and National Oceanic Atmospheric Agency (NOAA) space environmental operations centers are facing increasingly complex challenges meeting the needs of their growing user community. These centers provide current space environmental information and short term forecasts of geomagnetic activity. Recent advances in modeling and data access have provided sophisticated tools for making accurate and timely forecasts, but have introduced new problems associated with handling and analyzing large quantities of complex data. AI (Artificial Intelligence) techniques have been considered as potential solutions to some of these problems. Fielding AI systems has proven more difficult than expected, in part because of operational constraints. Using systems which have been demonstrated successfully in the operational environment will provide a basis for a useful data fusion and analysis capability. Our approach uses a general purpose AI system already in operational use within the military intelligence community, called the Temporal Analysis System (TAS). TAS is an operational suite of tools supporting data processing, data visualization, historical analysis, situation assessment and predictive analysis. TAS includes expert system tools to analyze incoming events for indications of particular situations and predicts future activity. The expert system operates on a knowledge base of temporal patterns encoded using a knowledge representation called Temporal Transition Models (TTM's) and an event database maintained by the other TAS tools. The system also includes a robust knowledge acquisition and maintenance tool for creating TTM's using a graphical specification language. The ability to manipulate TTM's in a graphical format gives non-computer specialists an intuitive way of accessing and editing the knowledge base. To support space environmental analyses, we used TAS's ability to define domain specific event analysis abstractions. The prototype system defines events covering reports of natural phenomena such as solar flares, bursts, geomagnetic storms, and five others pertinent to space environmental analysis. With our preliminary event definitions we experimented with TAS's support for temporal pattern analysis using X-ray flare and geomagnetic storm forecasts as case studies. We are currently working on a framework for integrating advanced graphics and space environmental models into this analytical environment.

Krajnak, Mike↗
NASA NTRS1995

Software engineering capability for Ada (GRASP/Ada Tool)

The GRASP/Ada project (Graphical Representations of Algorithms, Structures, and Processes for Ada) has successfully created and prototyped a new algorithmic level graphical representation for Ada software, the Control Structure Diagram (CSD). The primary impetus for creation of the CSD was to improve the comprehension efficiency of Ada software and, as a result, improve reliability and reduce costs. The emphasis has been on the automatic generation of the CSD from Ada PDL or source code to support reverse engineering and maintenance. The CSD has the potential to replace traditional prettyprinted Ada Source code. A new Motif compliant graphical user interface has been developed for the GRASP/Ada prototype.

Cross, James H., II↗
NASA NTRS1992

Display of scientific data structures for algorithm visualization

We present a technique for defining graphical depictions for all the data types defined in an algorithm. The ability to display arbitrary combinations of an algorithm's data objects in a common frame of reference, coupled with interactive control of algorithm execution, provides a powerful way to understand algorithm behavior. Type definitions are constrained so that all primitive values occurring in data objects are assigned scalar types. A graphical display, including user interaction with the display, is modeled by a special data type. Mappings from the scalar types into the display model type provide a simple user interface for controlling how all data types are depicted, without the need for type-specific graphics logic.

Hibbard, William↗
NASA NTRS1995

Visualization tools for the processing of airglow data from RAIDS

In anticipation of large data sets associated with a number of atmospheric imaging instruments being prepared for long term global coverage, NRL is developing graphical interfaces for all aspects of the program. For the first of these projects, RAIDS (the Remote Atmospheric and Ionospheric Detection System), a graphical approach to data handling, visualization, and analysis is envisioned and will set the stage for the satellites that follow. An overall system of hardware and a set of software 'tools,' that will allow for both the routine handling of all data and the analysis of large data sets assembled by scientists and instrument engineers, are currently being developed. The software for standard processing and visualization of instrument data is independent of computer platform and will allow for easy adaptation from one experiment to another. The processing will produce data sets that have similar characteristics, allowing for easy comparison of data obtained under similar circumstances. The visualization of both the engineering and scientific data is an important part of the system. By creating graphical environments for engineering evaluations and for scientific analysis data sets can be viewed and analyzed rapidly. This rapid analysis of data will contribute towards a greater portion of the RAIDS data being utilized.

Miller, Gordon J.↗
NASA NTRS1996

A study of wave propagation in a duct and mode radiation

In this paper we discuss two problems of classical duct acoustics: (1) wave propagation in infinite ducts with uniform flow based on a graphical approach, and (2) detection of mode radiation from a duct by an external circular microphone array. In (1) we show that the wave number vectors for a given flow Mach number form an ellipse whose center and shape depend on the Mach number only. We construct graphically the upstream and downstream wave number vectors of modes that propagate in the duct. We then show how one can infer from this graphical approach many known results in duct propagation such as the mode cut-off concept, the direction of energy propagation, the angle of the radiation lobe at peak directivity using Rice' s cutoff ratio concept, and other qualitative results. In (2) we give the mathematics behind the experimental detection of mode radiation from a duct by a circular array of microphones whose axis coincides with the engine axis. Since the external microphone array does not introduce additional noise sources inside the engine, as does a rotating rake of microphones positioned at the inlet, this measurement technique may be preferable to use of a rotating rake. The simplicity afforded by the lack of sophisticated rotating parts is an additional advantage over the rotating array.

Farassat, F.↗
NASA NTRS1996

The Integrated Mode Management Interface

Mode management is the processes of understanding the character and consequences of autoflight modes, planning and selecting the engagement, disengagement and transitions between modes, and anticipating automatic mode transitions made by the autoflight system itself. The state of the art is represented by the latest designs produced by each of the major airframe manufacturers, the Boeing 747-400, the Boeing 777, the McDonnell Douglas MD-11, and the Airbus A320/A340 family of airplanes. In these airplanes autoflight modes are selected by manipulating switches on the control panel. The state of the autoflight system is displayed on the flight mode annunciators. The integrated mode management interface (IMMI) is a graphical interface to autoflight mode management systems for aircraft equipped with flight management computer systems (FMCS). The interface consists of a vertical mode manager and a lateral mode manager. Autoflight modes are depicted by icons on a graphical display. Mode selection is accomplished by touching (or mousing) the appropriate icon. The IMMI provides flight crews with an integrated interface to autoflight systems for aircraft equipped with flight management computer systems (FMCS). The current version is modeled on the Boeing glass-cockpit airplanes (747-400, 757/767). It runs on the SGI Indigo workstation. A working prototype of this graphics-based crew interface to the autoflight mode management tasks of glass cockpit airplanes has been installed in the Advanced Concepts Flight Simulator of the CSSRF of NASA Ames Research Center. This IMMI replaces the devices in FMCS equipped airplanes currently known as mode control panel (Boeing), flight guidance control panel (McDonnell Douglas), and flight control unit (Airbus). It also augments the functions of the flight mode annunciators. All glass cockpit airplanes are sufficiently similar that the IMMI could be tailored to the mode management system of any modern cockpit. The IMMI does not replace the functions of the FMCS control and display unit. The purpose of the INMI is to provide flight crews with a shared medium in which they can assess the state of the autoflight system, take control actions on it, reason about its behavior, and communicate with each other about its behavior. The design is intended to increase mode awareness and provide a better interface to autoflight mode management. This report describes the IMMI, the methods that were used in designing and developing it, and the theory underlying the design and development processes.

Hutchins, Edwin↗
NASA NTRS1996

User's Guide for Flight Simulation Data Visualization Workstation

Today's modern flight simulation research produces vast amounts of time sensitive data. The meaning of this data can be difficult to assess while in its raw format. Therefore, a method of breaking the data down and presenting it to the user in a graphical format is necessary. Simulation Graphics (SimGraph) is intended as a data visualization software package that will incorporate simulation data into a variety of animated graphical displays for easy interpretation by the simulation researcher. This document is intended as an end user's guide.

Kaplan, Joseph A.↗
NASA NTRS1996

Development of a Flight Simulation Data Visualization Workstation

Today's moderm flight simulation research produces vast amounts of time sensitive data. The meaning of this data can be difficult to assess while in its raw format . Therefore, a method of breaking the data down and presenting it to the user in a graphical format is necessary. Simulation Graphics (SimGraph) is intended as a data visualization software package that will incorporate simulation data into a variety of animated graphical displays for easy interpretation by the simulation researcher. Although it was created for the flight simulation facilities at NASA Langley Research Center, SimGraph can be reconfigured to almost any data visualization environment. This paper traces the design, development and implementation of the SimGraph program, and is intended to be a programmer's reference guide.

Kaplan, Joseph A.↗
NASA NTRS1996

GRASP/Ada 95: Reverse Engineering Tools for Ada

The GRASP/Ada project (Graphical Representations of Algorithms, Structures, and Processes for Ada) has successfully created and prototyped an algorithmic level graphical representation for Ada software, the Control Structure Diagram (CSD), and a new visualization for a fine-grained complexity metric called the Complexity Profile Graph (CPG). By synchronizing the CSD and the CPG, the CSD view of control structure, nesting, and source code is directly linked to the corresponding visualization of statement level complexity in the CPG. GRASP has been integrated with GNAT, the GNU Ada 95 Translator to provide a comprehensive graphical user interface and development environment for Ada 95. The user may view, edit, print, and compile source code as a CSD with no discernible addition to storage or computational overhead. The primary impetus for creation of the CSD was to improve the comprehension efficiency of Ada software and, as a result, improve reliability and reduce costs. The emphasis has been on the automatic generation of the CSD from Ada 95 source code to support reverse engineering and maintenance. The CSD has the potential to replace traditional prettyprinted Ada source code. The current update has focused on the design and implementation of a new Motif compliant user interface, and a new CSD generator consisting of a tagger and renderer. The Complexity Profile Graph (CPG) is based on a set of functions that describes the context, content, and the scaling for complexity on a statement by statement basis. When combined graphicafly, the result is a composite profile of complexity for the program unit. Ongoing research includes the development and refinement of the associated functions, and the development of the CPG generator prototype. The current Version 5.0 prototype provides the capability for the user to generate CSDs and CPGs from Ada 95 source code in a reverse engineering as well as forward engineering mode with a level of flexibility suitable for practical application. This report provides an overview of the GRASP/Ada project with an emphasis on the current update.

Cross, James H., II↗
NASA NTRS1997

STARS: An Integrated, Multidisciplinary, Finite-Element, Structural, Fluids, Aeroelastic, and Aeroservoelastic Analysis Computer Program

A multidisciplinary, finite element-based, highly graphics-oriented, linear and nonlinear analysis capability that includes such disciplines as structures, heat transfer, linear aerodynamics, computational fluid dynamics, and controls engineering has been achieved by integrating several new modules in the original STARS (STructural Analysis RoutineS) computer program. Each individual analysis module is general-purpose in nature and is effectively integrated to yield aeroelastic and aeroservoelastic solutions of complex engineering problems. Examples of advanced NASA Dryden Flight Research Center projects analyzed by the code in recent years include the X-29A, F-18 High Alpha Research Vehicle/Thrust Vectoring Control System, B-52/Pegasus Generic Hypersonics, National AeroSpace Plane (NASP), SR-71/Hypersonic Launch Vehicle, and High Speed Civil Transport (HSCT) projects. Extensive graphics capabilities exist for convenient model development and postprocessing of analysis results. The program is written in modular form in standard FORTRAN language to run on a variety of computers, such as the IBM RISC/6000, SGI, DEC, Cray, and personal computer; associated graphics codes use OpenGL and IBM/graPHIGS language for color depiction. This program is available from COSMIC, the NASA agency for distribution of computer programs.

Gupta, K. K.↗
NASA NTRS1997

A Low Cost Simulation System to Demonstrate Pilot Induced Oscillation Phenomenon

A flight simulation system with graphics and software on Silicon Graphics computer workstations has been installed in the Flight Vehicle Design Laboratory at Tuskegee University. The system has F-15E flight simulation software from NASA Dryden which uses the graphics of SGI flight simulation demos. On the system, thus installed, a study of pilot induced oscillations is planned for future work. Preliminary research is conducted by obtaining two sets of straight level flights with pilot in the loop. In one set of flights no additional delay is used between the stick input and the appearance of airplane response on the computer monitor. In another set of flights, a 500 ms additional delay is used. The flight data is analyzed to find cross correlations between deflections of control surfaces and response of the airplane. The pilot dynamics features depicted from cross correlations of straight level flights are discussed in this report. The correlations presented here will serve as reference material for the corresponding correlations in a future study of pitch attitude tracking tasks involving pilot induced oscillations.

Ali, Syed Firasat↗
NASA NTRS1997

SPASIM: A Spacecraft Simulator

The SPAcecraft SIMulator (SPASIM) simulates the functions and resources of a spacecraft to quickly perform conceptual design (Phase A) trade-off and sensitivity analyses and uncover any operational bottlenecks during any part of the mission. Failure modes and operational contingencies can be evaluated allowing operational planning (what-if scenarios) and optimization for a range of mission scenarios. The payloads and subsystems are simulated, using a hierarchy of graphical models, in terms of how their functions affect resources such as propellant, power, and data. Any of the inputs and outputs of the payloads and subsystems can be plotted during the simulation or stored in a file so they can be used by other programs. Most trade-off analyses, including those that compare current versus advanced technology, can be performed by changing values in the parameter menus. However, when a component is replaced by one with a different functional architecture, its graphical model can also be modified or replaced by drawing from a component library. SPASIM has been validated using several spacecraft designs that were at least at the Critical Design Review level. The user and programmer guide, including figures, is available on line as a hypertext document. This is an easy-to-use and expandable tool which is based on MATLAB(R) and SIMULINK(R). It runs on Silicon Graphics Inc. workstations and personal computers with Windows 95(TM) or NT(TM).

Liceaga, Carlos A.↗
NASA NTRS1999

Automated Flight Dynamics Product Generation for the EOS AM-1 Spacecraft

As part of NASA's Earth Science Enterprise, the Earth Observing System (EOS) AM-1 spacecraft is designed to monitor long-term, global, environmental changes. Because of the complexity of the AM-1 spacecraft, the mission operations center requires more than 80 distinct flight dynamics products (reports). To create these products, the AM-1 Flight Dynamics Team (FDT) will use a combination of modified commercial software packages (e.g., Analytical Graphic's Satellite ToolKit) and NASA-developed software applications. While providing the most cost-effective solution to meeting the mission requirements, the integration of these software applications raises several operational concerns: (1) Routine product generation requires knowledge of multiple applications executing on variety of hardware platforms. (2) Generating products is a highly interactive process requiring a user to interact with each application multiple times to generate each product. (3) Routine product generation requires several hours to complete. (4) User interaction with each application introduces the potential for errors, since users are required to manually enter filenames and input parameters as well as run applications in the correct sequence. Generating products requires some level of flight dynamics expertise to determine the appropriate inputs and sequencing. To address these issues, the FDT developed an automation software tool called AutoProducts, which runs on a single hardware platform and provides all necessary coordination and communication among the various flight dynamics software applications. AutoProducts, autonomously retrieves necessary files, sequences and executes applications with correct input parameters, and deliver the final flight dynamics products to the appropriate customers. Although AutoProducts will normally generate pre-programmed sets of routine products, its graphical interface allows for easy configuration of customized and one-of-a-kind products. Additionally, AutoProducts has been designed as a mission-independent tool, and can be easily reconfigured to support other missions or incorporate new flight dynamics software packages. After the AM-1 launch, AutoProducts will run automatically at pre-determined time intervals . The AutoProducts tool reduces many of the concerns associated with the flight dynamics product generation. Although AutoProducts required a significant effort to develop because of the complexity of the interfaces involved, its use will provide significant cost savings through reduced operator time and maximum product reliability. In addition, user satisfaction is significantly improved and flight dynamics experts have more time to perform valuable analysis work. This paper will describe the evolution of the AutoProducts tool, highlighting the cost savings and customer satisfaction resulting from its development. It will also provide details about the tool including its graphical interface and operational capabilities.

Matusow, Carla↗
NASA NTRS2000

AWE: Aviation Weather Data Visualization Environment

The two official sources for aviation weather reports both provide weather information to a pilot in a textual format. A number of systems have recently become available to help pilots with the visualization task by providing much of the data graphically. However, two types of aviation weather data are still not being presented graphically. These are airport-specific current weather reports (known as meteorological observations, or METARs) and forecast weather reports (known as terminal area forecasts, or TAFs). Our system, Aviation Weather Environment (AWE), presents intuitive graphical displays for both METARs and TAFs, as well as winds aloft forecasts. We start with a computer-generated textual aviation weather briefing. We map this briefing onto a cartographic grid specific to the pilot's area of interest. The pilot is able to obtain aviation-specific weather for the entire area or for his specific route. The route, altitude, true airspeed, and proposed departure time can each be modified in AWE. Integral visual display of these three elements of weather reports makes AWE a useful planning tool, as well as a weather briefing tool.

Spirkovska, Lilly↗
NASA NTRS1994

FAST User Guide

The Flow Analysis Software Toolkit, FAST, is a software environment for visualizing data. FAST is a collection of separate programs (modules) that run simultaneously and allow the user to examine the results of numerical and experimental simulations. The user can load data files, perform calculations on the data, visualize the results of these calculations, construct scenes of 3D graphical objects, and plot, animate and record the scenes. Computational Fluid Dynamics (CFD) visualization is the primary intended use of FAST, but FAST can also assist in the analysis of other types of data. FAST combines the capabilities of such programs as PLOT3D, RIP, SURF, and GAS into one environment with modules that share data. Sharing data between modules eliminates the drudgery of transferring data between programs. All the modules in the FAST environment have a consistent, highly interactive graphical user interface. Most commands are entered by pointing and'clicking. The modular construction of FAST makes it flexible and extensible. The environment can be custom configured and new modules can be developed and added as needed. The following modules have been developed for FAST: VIEWER, FILE IO, CALCULATOR, SURFER, TOPOLOGY, PLOTTER, TITLER, TRACER, ARCGRAPH, GQ, SURFERU, SHOTET, and ISOLEVU. A utility is also included to make the inclusion of user defined modules in the FAST environment easy. The VIEWER module is the central control for the FAST environment. From VIEWER, the user can-change object attributes, interactively position objects in three-dimensional space, define and save scenes, create animations, spawn new FAST modules, add additional view windows, and save and execute command scripts. The FAST User Guide uses text and FAST MAPS (graphical representations of the entire user interface) to guide the user through the use of FAST. Chapters include: Maps, Overview, Tips, Getting Started Tutorial, a separate chapter for each module, file formats, and system administration.

Walatka, Pamela P.↗
NASA NTRS2001

Stator and Rotor Flux Based Deadbeat Direct Torque Control of Induction Machines

A new, deadbeat type of direct torque control is proposed, analyzed, and experimentally verified in this paper. The control is based on stator and rotor flux as state variables. This choice of state variables allows a graphical representation which is transparent and insightful. The graphical solution shows the effects of realistic considerations such as voltage and current limits. A position and speed sensorless implementation of the control, based on the self-sensing signal injection technique, is also demonstrated experimentally for low speed operation. The paper first develops the new, deadbeat DTC methodology and graphical representation of the new algorithm. It then evaluates feasibility via simulation and experimentally demonstrates performance of the new method with a laboratory prototype including the sensorless methods.

Kenny, Barbara H.↗