NASA 1987 SBIR Phase 1 Solicitation
Project Title:
Multigrid Solution of Internal Flows Using Generalized Solution Adaptive Meshes
01.01-3800
Multigrid Solution of Internal Flows Using
Generalized Solution Adaptive Meshes
Creare Incorporated
PO Box 71
Hanover, NH 03755
Wayne Smith (603-643-3800)
LeRC -- NAS3-25405
Abstract:
In this project, an innovative, interactive, general purpose solver for high-speed
compressible flows that uses unstructured, solution-adaptive meshes composed of tetrahedral
cells was investigated. Such a computer program will represent a significant advance
in the state of the art and will be a powerful tool for the study of inviscid and
turbulent three-dimensional transonic and supersonic flows.
The Phase I effort demonstrated that an unstructured, second-order accurate, finite-volume
formulation is able to produce accurate, highly detailed flow solutions. The unstructured
mesh formulation easily accommodates complex flow features such as shocks and boundary
layers. The mesh refinement algorithm provides highly localized mesh refinement while
maintaining excellent cell aspect and volume ratios.
Potential Commercial Application:
Potential Commercial Application: This code will have significant applications for
research and design involving high speed flows in turbines, compressors, inlets,
aircraft, and hypersonic flight vehicles.
Project Title:
Boundary Layer Control Methods in High Speed Inlet Systems
01.01-5094
Boundary Layer Control Methods in High Speed
Inlet Systems
Rose Engineering & Research, Inc.
PO Box 5146
Incline Village, NV 89450
William C. Rose (702-831-5094)
LeRC -- NAS3-25408
Abstract:
The objective of the Phase I effort was to determine the feasibility of using
innovative, boundary-layer control arrangements that allow high inlet recovery to
be achieved at low bleed rates. This analytical investigation was carried out with
the use of a full Navier-Stokes code, and a review was conducted of the relevant
literature on recent developments in boundary-layer control in high-speed engine
inlets. Of particular interest were inlets intended to operate at flight Mach numbers
above 3.0 where viscous effects dominate the behavior of the internal flow.
Various proposed flow control techniques were investigated. The cutback sidewall
technique was very successful at minimizing distortion, but an unknown and potentially
debilitating amount of the inlet mass flow would, of necessity, be spilled as a result
of the lack of the lateral sidewalls. The Phase I effort concentrated on the "design"
value for Mach 5; however, it is recognized that flow control methods must work across
a wide range of Mach numbers.
Potential Commercial Application:
Potential Commercial Application: Commercial applications include military aircraft
and civilian aircraft used for transportation of people and packages throughout the
world.
Project Title:
Advanced Thermal Protection Materials
01.02-0236
Advanced Thermal Protection Materials
Ultramet
12173 Montague Street
Pacoima, CA 91331
Richard B. Kaplan (818-899-0236)
LeRC -- NAS3-25411
Abstract:
The objective of this project is to develop a new process for making light-weight,
high-temperature, high-performance structural materials for use in hot section components
of aircraft propulsion engines through an innovative application of chemical vapor
deposition and infiltration (CVD or CVI). The process involves infiltrating a reticulated
carbon foam with rhenium, sheathing it with rhenium to form a quasi-honeycomb structure,
and overcoating the resultant composite structure with a refractory ceramic for oxidation
and erosion protection.
Phase I thoroughly investigated the rhenium infiltration process to form a refractory-metal
foam; however, equipment and time limitations did not allow a determination of the
effects of a rhenium sheath on the foam properties. Nevertheless, application of
a sheath on the foam caused a 2000 percent increase in crush strength from 1000 psi
to >20,000 psi, the load cell limit. The drastic increase in strength results from
an almost complete load transfer and uniform stress distribution over the stronger
"skin" of the structure. One-sided heating tests demonstrated the material's high
thermal impedance, stability, and shock resistance. Oxidation protection for the
rhenium, using a diffusion barrier and Hf-Si-C deposited on the foam structure, was
demonstrated by inspection of the surface after heating with an H2-O2 torch to 1800
C.
Potential Commercial Application:
Potential Commercial Application: Primary applications are for a combustor liner
in advanced small gas turbine engines; for other hot section components of jet engines
such as turbine shrouds, exhaust nozzles and nozzle liners, and convergent and divergent
flaps; for hot gas valves and rocket nozzles; and for oxidation protection of refractory
metals and intermetallics.
Project Title:
Pulse Combustor Driven Recuperated or Regenerated Gas Turbine
01.02-7300
Pulse Combustor Driven Recuperated or
Regenerated Gas Turbine
Altex Technologies Corporation
650 Nuttman Road
Santa Clara, CA 95054
John T. Kelly (408-395-7300)
LeRC -- NAS3-25404
Abstract:
The goal of achieving minimum-volume, light-weight, efficient and environmentally
clean "small" gas-turbine systems for aircraft propulsion may be met with an innovative
pulsed-combustor-driven, recuperated or regenerated, gas turbine (PCRGT) concept.
It is based upon the fact that pulsating combustion generates velocity fluctuations
which propagate throughout the system and increase heat and mass transport. Combustion
and diluent air mixing are intensified by the pulsations, thereby leading to greater
combustion efficiency and smaller and lighter combustors. Pressure is gained across
the combustor, which directly increases cycle efficiency. Heat-exchanger heat transport
is significantly improved, leading to smaller and lighter heat exchangers.
Under the Phase I SBIR effort, the concept was analytically evaluated and shown
to reduce small gas turbine specific fuel consumption by 22 percent, increase specific
power by 32 percent, reduce recuperator volume and weight by 46 percent and 32 percent,
respectively, and reduce emissions of oxides of nitrogen by 75 percent. These substantial
increases in engine performance were found to require minimal engine modifications
beyond replacing the steady flow combustor with a pulsating combustor.
Potential Commercial Application:
Potential Commercial Application: The PCRGT concept is applicable to a wide variety
of commercial and government aircraft propulsion, ground transportation, and power
generation applications.
Project Title:
Propeller-Wake-Induced Structure-Borne Interior Noise
01.02-9511
Propeller-Wake-Induced Structure-Borne Interior
Noise
Dynamic Analysis & Testing Associates
2231 Faraday Avenue, Suite 103
Carlsbad, CA 92008
C. Thomas Savell (619-931-9511)
LeRC -- NAS3-25338
Abstract:
The purpose of this project is to establish a unified model for predicting the
portion of the interior, aircraft-cabin noise transmitted through the wing structure
and produced by the wake from a wing-mounted propeller. The method used: a velocity
defect model representing the viscous wake behind a twisted and leaned prop-fan blade;
standard acoustic source modeling methods to describe the wing vibration and pressure
loading perturbation resulting from the wake slapping the wing; and finite-element,
acoustic-structure interaction analysis to predict the vibration energy transmission
through the wing structure, the excitation of the rest of the aircraft structure,
and the resulting noise radiation to the interior of the aircraft cabin.
In Phase I several computer codes were developed for analyzing the acoustic-structure
interaction problem of the noise experienced in the interior of an aircraft driven
by advanced prop-fans. Simplified models of the aircraft wing, fuselage, and cabin
interior were used. The wing was modeled as three beam sections of different thickness
joined to the fuselage side panels. The fuselage panels were modeled as flat plates
attached to stringers at the edges. The cabin interior was modeled as a rectangular
cavity. The final computer model was exercised in a parametric study in which the
wing and fuselage section properties and joining conditions were varied.
Potential Commercial Application:
Potential Commercial Application: There is an industry-wide need for a general purpose
code to solve acoustic-structure interaction problems for all forms of transportation
vehicles, in acoustic fatigue and failure analysis, and in general architectural
acoustics.
Project Title:
Simultaneous Temperature, Density, and Flow Diagnostics for Aeropropulsion Systems
01.03-1520
Simultaneous Temperature, Density, and Flow
Diagnostics for Aeropropulsion Systems
Deacon Research
900 Welch Road, Suite 203
Palo Alto, CA 94304
Anthony O'Keefe (415-326-1520)
LeRC -- NAS3-25401
Abstract:
The design of advanced propulsion systems requires simultaneous measurement of
the flow velocities and the thermodynamic properties in order to verify the mathematical
models based on the time-averaged, Navier-Stokes equations. The coherent anti-Stokes
Raman scattering (CARS) technique makes possible the measurement of the temperature
and pressure but not velocity. Laser Doppler velocimeters fail at high velocities
because the measured dust particles no longer follow the flow lines. The innovation
is in combining CARS with a well-known spectroscopic technique, stimulated Brillouin
scattering (SBS), which can measure flow velocity from subsonic through hypersonic
speeds. By adding a detection system and changing the CARS geometry slightly, one
can measure the flow velocity, temperature, and density with a single, stop-motion
laser pulse.The Phase I investigation showed that an SBS system can be configured
to measure velocities in the range of Mach 0 to 20 and above with an accuracy of
Mach 0.02, expanding, thereby, the range of velocity measurements more than an order
of magnitude. An SBS technique can also be coupled with a CARS measurement of the
temperature and density so that the three critical variables of the Navier-Stokes
equations can be measured independently within 100 ns of each other.
Potential Commercial Application:
Potential Commercial Application: An SBS velocimeter could find applications not
only at ground-based testing facilities but also in flight testing, where the SBS
configuration makes these simultaneous flow and thermodynamic measurements possible
for the first time.
Project Title:
High-Temperature LDV Seed Particle Development
01.03-9030
High-Temperature LDV Seed Particle
Development
Physical Sciences Inc.
Research Park
PO Box 3100
Andover, MA 01810
Michael B. Frish (508-475-9030)
LeRC -- NAS3-25284
Abstract:
To perform laser Doppler velocimetry (LDV) in the gas flows of aerospace propulsion
systems, light scattering particles able to withstand the harsh ambient environment
are needed. This project explored the feasibility of manufacturing mono-disperse,
heat-resistant particles having diameters of 0.05 to 0.5 m which can be seeded into
the flow. The technique employs a pulsed, CO2 laser to decompose gases flowing in
a supersonic nozzle, resulting in vapor products which condense, polymerize, or react
to form carbonaceous or silicon particulates which are prevented from agglomerating.
The particles generated were collected, evaluated for size and shape by electron
microscopy, and checked for agglomeration.
In Phase I, a small-scale feasibility study, non-agglomerated, nearly mono-disperse
carbonaceous spheres, typically 100 to 500 nm in diameter, were made by pyrolysis
of ethylene with a pulsed laser. It is expected that, by pyrolysis of other gases
or gas mixtures, this process or a similar one can be made to yield a multitude of
different particle compositions and sizes that can be selected as required to suit
specific LDV seeding applications.
Potential Commercial Application:
Potential Commercial Application: Applications include LDV seeding and the commercial
ceramics or abrasive materials manufacturing field where mono-disperse, non-agglomerated
powders having particle diameters ranging from tens to thousands of nanometers are
highly desirable.
Project Title:
Supersonic Turbulent Reacting Flow Modeling and Calculation
01.04-9457
Supersonic Turbulent Reacting Flow Modeling
and Calculation
Nielsen Engineering & Research, Inc.
510 Clyde Avenue
Mountain View, CA 94043
Mohammed Farschi (415-968-9457)
LeRC -- NAS3-25285
Abstract:
Accurate modeling and calculation of supersonic turbulent reacting flows depends
on a thermochemical model that can account for dominant time scales involved in the
reaction and a turbulence model capable of predicting the effects of compressibility
and heat release. This project addresses a method of modeling supersonic combustion
through the use of a probability-density function (PDF) of scalars in the reaction.
The method accounts for the effects of compressibility and heat release in the turbulent
kinetic energy and length scales by analysis of exact pressure and vorticity equations.
Phase I of the work concentrated on the analysis of the properties of pressure fluctuations
and development of a second-order turbulence closure model. Also a specified PDF
model was used to relate the local thermodynamic state to a single, conserved scalar
for an equilibrium chemical reaction. These models were implemented in a two-dimensional
Navier-Stokes solver and applied to several test cases.
Phase I had four significant results. General governing equations for compressible,
turbulent chemically reacting flows were developed. The role of pressure-velocity
correlations for compressible, turbulent flows was analyzed and used to develop a
Reynolds stress turbulence model accounting for compressibility effects. An eddy-viscosity
turbulence model for scalar fluxes along with an assumed PDF thermochemical model
based only on the mean values was used. A numerical technique was chosen and developed
for the solution of the coupled set of governing equations obtained from the above
closure models.
Potential Commercial Application:
Potential Commercial Application: A versatile and efficient computer code with simple
but accurate chemical reaction and non-equilibrium turbulence models in supersonic
flow regions will be used by aircraft engine companies and defense industries and
by researchers and consulting engineers in a variety of other applications such as
laser technology.
Project Title:
Shock Waves for Enhanced Mixing in Scramjet Combustors
01.05-8500
Shock Waves for Enhanced Mixing in Scramjet
Combustors
Flow Research, Inc.
21414 68th Avenue South
Kent, WA 98032
Suresh Menon (206-872-8500)
LeRC -- NAS3-25332
Abstract:
For an efficient supersonic combustion ramjet (scramjet), mixing enhancement between
the incoming supersonic air and the injected fuel is essential. However, at hypersonic
flight speeds, the short residence time and decreased mixing rate cause deterioration
in the combustion efficiency as compared with lower speeds. A configuration recently
developed to promote rapid mixing in a supersonic flow is a single-step flame holder
with a wedge on the opposite supersonic passage wall to induce a weak shock. The
objective of this project is to evaluate the configuration as a means for rapid and
thorough mixing of the fuel with the supersonic air stream through interactions between
the shock wave and shear layer.
During Phase I, the interaction between a shock wave generated by a wedge and a
supersonic (Mach 2.5) mixing layer was investigated by observing the mixing between
two species (nitrogen and helium) downstream of a scramjet flame holder (i.e., rearward-facing
step). Schlieren flow visualization and Rayleigh scattering concentration measurements
indicate that significant spreading of the mixing layer may be occurring downstream
of the shock impingement region. It appears that the shock wave/shear layer interaction
allows the helium to diffuse more rapidly across the supersonic nitrogen flow.
Potential Commercial Application:
Potential Commercial Application: The flame holder design, the experimental data,
and the diagnostic instrumentation developed in this project will be provided to
NASA for practical evaluation in the scramjet engine.
Project Title:
Adaptive Schemes for Complex Subsonic 3D-Flow Problems in Arbitrary Domains
02.01-0618
Adaptive Schemes for Complex Subsonic 3D-Flow
Problems in Arbitrary Domains
The Computational Mechanics Company, Inc.
3701 N. Lamar, Suite 201
Austin, TX 78705
Jon M. Bass (512-467-0069)
MSFC -- NAS8-37621
Abstract:
The innovation explored in this project is in fully adaptive computational schemes
with quantitative measures of the accuracy of solutions of very complex problems
in fluid dynamics. Particular emphasis is given to the development of models for
subsonic, three-dimensional flow problems in arbitrary domains.
Phase I involved detailed studies of the feasibility of the development of new algorithms
for subsonic flows. In the area of adaptive methods, some encouraging results have
been obtained in the development of a fast, mesh refinement strategy that dynamically
allocates cell and node numbers. The method leads to fully unstructured meshes and
can automatically refine an unstructured mesh so as to keep cell errors within preassigned
limits. In addition, pilot codes on combined mesh refinement and spectral-order enrichment
were developed and tested. In the area of error estimation, new and general error
estimation techniques were developed which produced results superior to existing
error estimation methods. Overall, several new developments in computational fluid
dynamics have been made which could improve the reliability and efficiency with which
subsonic flow problems are analyzed.
Potential Commercial Application:
Potential Commercial Application: Numerous commercial applications are possible for
design analysis of low-Mach number flows in rocket propulsion systems, pumps, turbo-machinery,
ducts, and channels and on aerodynamic surfaces.
Project Title:
Software Package for Solving Large Systems of Nonlinear Equations
02.01-3600
Software Package for Solving Large Systems of
Nonlinear Equations
Kuck and Associates, Inc.
1808 Woodfield Drive
Savory, IL 61820
Ahmed Sameh (217-344-3600)
MSFC -- NAS8-37633
Abstract:
The numerical simulation of many problems in engineering leads to solving large
systems of nonlinear equations. In the past this has required developing a host of
specialized codes to solve scientific problems in various applications areas. The
goal of this project is a general package for solving nonlinear systems of equations
that would include the most recent innovations in solutions of nonlinear and linear
equations which have great potential benefits to the scientific community.
In Phase I, a few preliminary kernels of such a package were implemented and tested
on a number of sample problems arising mostly from computational fluid dynamics.
The numerical methods tested include a nonlinear GMRES (generalized minimal residual)
method with point Gauss-Seidel, line, and biharmonic preconditioning and a standard
Newton method with the Jacobian system solved by either a direct solver or an iterative
solver. All the above techniques gave execution times several orders of magnitude
smaller than MINPACK, one of the only existing public domain packages available for
solving nonlinear systems of equations.
Potential Commercial Application:
Potential Commercial Application: A package for solving general, large systems of
equations efficiently would provide research groups in industry, government, and
universities with a tool that can be integrated into existing codes.
Project Title:
Computational Fluid Dynamics of Store Separation
01-3922
Computational Fluid Dynamics of Store
Separation
JAI Associates, Inc.
PO Box 293
Mountain View, CA 94086
Samuel P. Shanks (415-964-3922)
ARC -- NAS2-12779
Abstract:
Development of a three-dimensional, computational fluid dynamics code was studied
to provide reliable, economic computations of store separation from an aircraft where
the stores have plumes. The purpose of this code is to study plume ingestion and
mutual aerodynamic interference between the store and the aircraft. The effort in
this project is consistent with and meant to complement the on-going shuttle work
at NASA Ames.
Phase I provided a study of the three-dimensional static CHIMERA code to determine
how best to modify it for store separation and how best to include a plume. A generic
wing was chosen with a generic missile without fins. An algebraic grid generator
was written for fighter wings. The codes were modified for the wing and wing-store
solutions. Several wing-alone runs were made to test the accuracy of the flow solver.
Issues pertinent to store separation were identified and solution theory was formulated.
Potential Commercial Application:
Potential Commercial Application: The general method may apply to the calculation
of ground effects on automobile performance and transient aerodynamic effects of
two or more closely moving bodies, e.g., the effects of wing tip vortices from large
aircraft on other aircraft.
Project Title:
Propulsion Simulation for Magnetically Suspended Wind Tunnel Models
02.02-9030
Propulsion Simulation for Magnetically
Suspended Wind Tunnel Models
Physical Sciences Inc.
Research Park
PO Box 3100
Andover, MA 01810
Prakash B. Joshi (617-475-9030)
LaRC -- NAS1-18616
Abstract:
The purpose of this project is to provide innovative methods for simulating propulsion
effects in aerodynamic research conducted with models in magnetic suspension wind
tunnels. The feasibility of various techniques of generating exhaust jets of appropriate
characteristics was evaluated in Phase I. Judgments of feasibility considered the
ability of the selected methods to generate model flow rates and velocities of propulsive
jets for a variety of aircraft configurations, flight regimes, and model scales.
Four concepts of remotely-operated propulsion simulators were examined. Three conceptual
designs involving innovative adaptation of conventional technologies (compressed
gas cylinders, liquid, and solid propellants) were developed. The fourth innovation,
namely, the laser-assisted thruster, which can potentially simulate both inlet and
exhaust flows, was found to require very high power levels for small thrust levels.
This concept needs further research.
Potential Commercial Application:
Potential Commercial Application: Applications would be in conducting aerodynamic
research in wind tunnels equipped with magnetic devices for model suspension.
Project Title:
Modelling of Massively Separated Flows: Renormalization Group Formulation
02.03-9778
Modelling of Massively Separated Flows:
Renormalization Group Formulation
Spectrex, Inc.
PO Box 707
Gloucester, VA 23061
R. Balasubramanian (804-693-9778)
LaRC -- NAS1-18610
Abstract:
The overall goal of this project is to describe the behavior of massively separated
flows using turbulence models based on renormalization group methods and spectral
patching elements that easily model complex geometries. Existing turbulence transport
models often fail to describe the behavior of non-equilibrium turbulent flows in
which there are strong deviations from the law-of-the-wall. This breakdown may be
traced to an inadequate treatment of the interaction between eddy and molecular transport
in the wall layers. The firm developed a new method based on renormalization group
techniques that have been shown to perform well in a variety of situations, including
non-equilibrium flows. The success of these techniques originates from the fact that
they are differential in character and not based on classical ad hoc algebraic relations.
In Phase I, a new, differential, turbulence-transport model based on renormalization
group methods was developed and validated to solve turbulence problems involved in
massively separated flows. Issues concerning boundary conditions, numerical stiffness,
and wall region modelling with recirculation zones were successfully addressed.
Potential Commercial Application:
Potential Commercial Application: Many practical commercial engineering problems
involve massively separated flows, at both high Mach numbers and low speeds, for
which these renormalization group models provide a key new technology.
Project Title:
Three-Dimensional Euler Solver
02.04-8450
Three-Dimensional Euler Solver
G.M.A.F., Inc.
PO Box 184
Freeport, NY 11520
Gino Moretti (516-378-8450)
LaRC -- NAS1-18618
Abstract:
The computational technique for two-dimensional, unsteady flows developed by the
firm (a combination of the lambda-scheme and shock-fitting) produces excellent results
and requires substantially less computational time than shock-capturing techniques.
Extending the technique to three-dimensional flows and conducting several feasibility
tests, including some with complicated shock patterns in ducts, are the goals of
this project.
Phase I showed the feasibility of the project, using both H-grids and Cartesian
grids with a special treatment for wall points.
Potential Commercial Application:
Potential Commercial Application: The method applies to the analysis of intake and
nozzle designs for supersonic flows.
Project Title:
Computations of Separated Flows with Two Equation Models
02.05-1427
Computations of Separated Flows with Two
Equation Models
Applied & Theoretical Mechanics, Inc.
4501 Sequoyah Road
Oakland, CA 94605
Joelle M. Champney (415-635-1427)
ARC -- NAS2-12778
Abstract:
This project has resulted in a practical numerical model for use by research personnel
to test and develop turbulence models. The selected numerical model was the TURF
code (Coakley, 1984). As part of the effort, the code was organized in a user-friendly,
modular form and verified on simple test problems for which analytical solutions
exist. The innovative turbulence model designed by Mansour, Kim and Moin (1987),
called the MKM model, was implemented in the code. The model was successfully tested
for channel flow and applied to flows with separation. The experimental flows studied
were a backward-facing step and a two-dimensional compression corner at a Mach number
of 2.8. The MKM model was compared to the Jones-Launder, Chien, and Coakley (version
1) two-equation models.
Potential Commercial Application:
Potential Commercial Application: This effort will provide a versatile, easy-to-modify,
numerical tool to be utilized by workers in turbulence modeling and aircraft design.
Project Title:
Stimulated Brillouin Diagnostics of Hypersonic Flows
02.06-1520
Stimulated Brillouin Diagnostics of Hypersonic
Flows
Deacon Research
900 Welch Road, Suite 203
Palo Alto, CA 94304
Anthony O'Keefe (415-326-1520)
JSC -- NAS9-17937
Abstract:
Conventional laser Doppler velocimetry fails for supersonic or turbulent flows.
As an alternative, a remote velocity sensor based on stimulated Brillouin scattering
(SBS) was investigated. This innovation should operate reliably both at low and high
speeds and offer the same scanning capability with better time resolution than the
existing technique. Because of the phase conjugation property of SBS resulting in
near 100 percent backscatter, this system provides a unique opportunity for measuring
supersonic airflows in the vicinity of aircraft in flight. Such a capability will
allow a better understanding of the factors limiting the performance envelope of
new and existing airframes and provide benchmark information for the simulation codes
in a parameter range which cannot be reproduced in wind tunnels.
Phase I work involved scaling of SBS characteristics based upon both the theoretical
and the experimental investigations of the SBS process reported in the literature.
This study has shown that such a system can be built with commercially available
components.
Potential Commercial Application:
Potential Commercial Application: This new technology is expected to play an important
role in the development of new high speed airframes and conceivably in the extension
of the performance envelope of existing ones.
Project Title:
A Laser-Based Transition Detector
02.06-5630
A Laser-Based Transition Detector
Complere, Inc.
PO Box 1697
Palo Alto, CA 94302
F. K. Owen (415-321-5630)
ARC -- NAS2-12781
Abstract:
One of the largest sources of uncertainty in proposed hypersonic testing of the
National Aerospace Plane will be the measurement of the extent of laminar flow on
wind tunnel test models with free and forced transition. In an attempt to alleviate
this problem, a novel concept for the remote detection of boundary-layer transition
has been investigated. This laser-based turbulent burst detector will enable non-intrusive,
microscopic studies of the onset and extent of transition by rapidly scanning boundary
layers on wind tunnel models. The potential of this new instrument will be in the
capability it provides for the rapid mapping of irregular transition patterns which
often occur on complicated wind-tunnel test models. It will also replace the impractically
large numbers of surface gages which would be required for transition measurement
and so substantially reduce model construction costs and wind-tunnel test time. Completion
of this project has been delayed pending the availability of the 3.5 foot wind tunnel
at NASA-ARC.
Potential Commercial Application:
Potential Commercial Application: This innovation would replace the impractically
large numbers of surface gages required in rapid mapping of irregular flow patterns
on complicated wind tunnel test models, reducing model costs and test time.
Project Title:
Photochemical Ignition and Enhancement of Supersonic Combustion
02.06-7970
Photochemical Ignition and Enhancement of
Supersonic Combustion
M. L. Energia, Inc.
PO Box 1468
Princeton, NJ 08542
Moshe Lavid (609-799-7970)
ARC -- NAS2-12782
Abstract:
Significant and revolutionary advances in combustion technology are needed for
the new generation of hypersonic flight vehicles. The condition of high-speed flight
imposes severe strains on ignition, overall efficiency, and stability of combustion
which are risks to the success of the hypersonic program. A novel approach to alleviate
these difficulties was proposed and successfully tested under a Phase I feasibility
study. The innovative idea is to irradiate selectively targeted species in the reaction
zone. The ensuing photo-dissociation reactions generate highly reactive radicals
which significantly modify the kinetics leading to ignition and enhancement via chain
branching paths.
The experiments were fully successful in demonstrating that photo-dissociation of
sensitizers, e.g. NO2, can significantly modify combustion processes. Specifically,
ignition was demonstrated at conditions where conventional ignition has failed. Explosion
limits were also extended. These findings suggest that other combustion properties,
e.g. ignition delay time and flame speed, can also be favorably affected by this
innovative idea.
Potential Commercial Application:
Potential Commercial Application: Potential commercial applications include the Aero-Assisted
Orbital Transfer Vehicle (AOTV), the National Aerospace Plane (NASP) and the Supersonic
Transport (SST).
Project Title:
Aerothermodynamic Radiation Studies
02.06-9030
Aerothermodynamic Radiation Studies
Physical Sciences Inc.
Research Park
PO Box 3100
Andover, MA 01810
George E. Caledonia (617-475-9030)
JSC -- NAS9-17949
Abstract:
The ability to predict accurately radiative heat transfer from the non-equilibrium
bow shock of vehicles operating at hypersonic velocities and elevated altitudes is
critical to the design of large NASA vehicles such as the Aero-Assisted Orbital Transfer
Vehicle. The extant data base is insufficient to validate models used for this purpose.
In the Phase I effort, this project demonstrated that an optical, multi-channel
analyzer can be used to measure accurately the temporal and spectral behavior of
non-equilibrium, shock-heated air and that data can be analyzed to deduce temporally
excited state population histories even in the presence of overlapping band systems.
An innovative technique was also developed for the measurement of N2(X) vibrational
relaxation behind a shock front. The Phase I effort has demonstrated that the integration
of modern measurement techniques with a modern shock tube experiment can provide
the necessary data for improving the predictive capabilities of computer-based radiation
models used to design advanced re-entry vehicles.
Potential Commercial Application:
Potential Commercial Application: Applications of this facility would be in the study
of chemical kinetics and radiative phenomena in high-temperature gases and molecular
systems not readily studied by existing techniques.
Project Title:
Rarefied Gas Aerodynamic Bridging Procedures
02.07-8581
Rarefied Gas Aerodynamic Bridging Procedures
Remtech, Inc.
3304 Westmill Drive
Huntsville, AL 35805
E. C. Knox (205-536-8581)
MSFC -- NAS8-37635
Abstract:
Shuttle flight data have shown that the "bridging" relations used to predict the
Shuttle reentry aerodynamics in the rarefied-gas portion of its trajectory were inadequate
in that twice the predicted body-flap deflection was required to trim the vehicle.
Fortunately, there was sufficient margin built into the Shuttle; however, providing
such margins on future vehicle designs may render them not viable. For example, the
next generation of spaceflight vehicles, such as the Aero-Assisted Flight Experiment
(AFE) currently being designed, will require more precise predictions of the vehicle
aerodynamics in the transitional flow regime in order to reduce the allowance for
propellants in favor of increased payload.
In Phase I the bridging techniques and formulas used to connect the continuum with
the free-molecular flow regime in predicting the aerodynamic characteristics of vehicles
designed to fly in the rarefied gas regime were revisited. Results from the Phase
I study show that some improvements can be made in the bridging techniques, but that
further work is needed to account for real-gas effects and molecular-surface interactions.
Failure to account for the molecular-surface interactions can cause the drag on a
typical vehicle operating in this regime to be in error by as much as 25 percent.
Potential Commercial Application:
Potential Commercial Application: Applications would be for spacecraft operating
between the continuum region near the earth and the free-molecular regime of space.
Project Title:
Direct Simulation Monte Carlo of Vacuum Plumes
02.08-1759
Direct Simulation Monte Carlo of Vacuum Plumes
Ergo-Tech Systems Inc.
6937 Estepa Drive
Tujunga, CA 91042
Jose E. Chirivella (818-352-1759)
MSFC -- NAS8-37623
Abstract:
The overall objective of this project is the development of a three-dimensional,
direct-simulation, Monte Carlo (DSMC) code to model the interaction of rocket vacuum
plumes with spacecraft structures and the surrounding atmosphere. This work focuses
on the complex flow field encountered in the wakes of trans-atmospheric vehicles
operating from an altitude of 75 km to a low earth orbit.
The methods to link the continuum plume with the DSMC molecular description were
studied in Phase I. An axially symmetric code (Atlantic 1.3) which can handle an
unlimited number of species, structural segments, and molecular sources was developed
and applied in simulating the interaction of the base of the Aero-Assisted Flight
Experiment vehicle with its reaction control thrusters. A more advanced version,
Atlantic 1.4, tested by simulating the firing of a thruster within a vacuum chamber,
features improved accuracy, increased efficiency, multiple region topology, and an
architecture that can be readily extended to three dimensions. Phase I has shown
the feasibility of direct-simulation Monte Carlo to model and conduct numerical experiments
when the flow pattern and geometry are extremely complex.
Potential Commercial Application:
Potential Commercial Application: Monte Carlo simulation of the dynamics of complex
systems may solve a difficult, important problem in space technology and could be
reformulated to treat other stochastic systems which appear in nucleonics, robotics,
and bio-technology.
Project Title:
Numerical Modeling of Fully Viscous Rocket Plume Flows
02.08-8150
Numerical Modeling of Fully Viscous Rocket
Plume Flows
GT-Devices, Inc.
5705 General Washington Drive
Alexandria, VA 22312
Rodney L. Burton (703-642-8150)
LeRC -- NAS3-25407
Abstract:
The plume produced by the gas flow through the nozzle of a rocket engine or system
vent on a spacecraft can contaminate the spacecraft, its sensors, and other nearby
apparatus. Current analytical methods patch numerical solutions for the nozzle core
flow to those for the boundary layer flow. The resulting continuum solution is then
patched to a Monte Carlo calculation for the free-molecular regime. This approach
only models steady plumes so that the start-up and shut-down problems cannot be investigated.
This project addressed the problem of non-steady plume flows by means of a two-dimensional,
fully viscous, non-steady solution for the continuum regime. This numerical method
is well-adapted to solving time-dependent flows including viscosity, steep gradients,
and even shocks and is, therefore, capable of calculating the fully time-dependent
flow of a rocket nozzle during a complete pulse.
Phase I demonstrated the feasibility of using the flux-corrected transport (FCT)
algorithm with constant viscosity to model non-steady, axially symmetric flow of
CO2 in a conical nozzle and in the forward plume region. The computations were validated
with experimental nozzle data and were shown to give agreement of better than 7 percent
for total pressure, exhaust velocity, and boundary layer thickness as far as 1.5
nozzle diameters downstream. Shutdown flow was also modeled.
Potential Commercial Application:
Potential Commercial Application: PC-based calculation of rocket engine forward and
back-flow plumes for axially symmetric nozzles of general shape and simple chemistry
in vacuum will be possible.
Project Title:
Vacuum Plume Impingement Evaluator
02.08-8581A
Vacuum Plume Impingement Evaluator
Remtech, Inc.
3304 Westmill Drive
Huntsville, AL 35805
Robert L. Bender (205-536-8581)
MSFC -- NAS8-37636
Abstract:
As an Orbital Maneuvering Vehicle or astronauts seated in the Man Maneuvering Unit
move externally about the Space Station to perform assembly, maintenance, payload
servicing, and other extra-vehicular activities, the plumes from the reaction-control
micro-thrusters may impinge on various structures and payloads and create locally
severe environments and surface contamination. The possibilities for potentially
severe impingement and contamination are unbounded since mission plans are not final,
station growth will occur, and payloads will be constantly changing.
An engineering tool was studied which will geometrically track an arbitrary thruster
vacuum plume over an orbiting spacecraft, provide a quick computation of the environment
at any nozzle position, and evaluate the criticality of the impingement environment.
Phase I research established the feasibility of utilizing a three-dimensional, color
graphics display of the impingement zone as the means to evaluate the environment.
A quick, visual assessment of the impingement environments is possible even over
a complex structure with a variety of components and shapes. The static problem where
the plume is fixed relative to the impinged structure was thoroughly exercised in
Phase I.
Potential Commercial Application:
Potential Commercial Application: This development applies to the design of a spacecraft
or satellites for simulating and assessing impingement of plumes of gas prior to
flight.
Project Title:
Low-Speed Visualization Studies of Vortex Systems on Chine-Forebody/Delta Wing
02.09-0794A
Low-Speed Visualization Studies of Vortex
Systems on Chine-Forebody/Delta Wing
Configurations
Vigyan Research Associates, Inc.
30 Research Drive
Hampton, VA 23666
Dhanvada M. Rao (804-865-1400)
ARC -- NAS2-12780
Abstract:
Fore-bodies with vortex-generating side edges or chines blending into highly swept
leading edges are known to stabilize leading edge vortices through aerodynamic coupling
at high angles of attack. However, in post-stall maneuvering flight, chine-vortex
interaction with the wing and vertical tails can lead to roll and yaw sensitivity
together with reduced or negative damping, making the configuration prone to departure.
This research explored the feasibility of decoupling the chine and wing vortices
by applying three alternate geometrical modifications whose effectiveness on a generic,
delta-wing fighter configuration were investigated through low-speed, wind-tunnel
flow visualizations in a broad angle-of-attack and sideslip envelope.
Smoke visualizations and limited wing-pressure surveys indicated that vortex decoupling
could be achieved by introducing a local discontinuity at the chine and leading-edge
junction and, even more effectively, by deflecting inboard leading-edge flaps.
Potential Commercial Application:
Potential Commercial Application: These results will be used by the national aeronautical
industry involved in tactical aircraft developments of the U.S. Air Force and Navy.
Project Title:
Wing-Rock Dynamics and Control
09-9316
Wing-Rock Dynamics and Control
Eidetics International, Inc.
3415 Lomita Boulevard
Torrance, CA 90505
T. Terry Ng (213-326-8228)
ARC -- NAS2-12787
Abstract:
Modern fighter aircraft operate with increasing demands for maneuverability and
controllability in order to track targets accurately for gun or missile shots. A
self-induced, limit-cycle oscillation in roll, wing-rock, is sometimes accompanied
by coupled oscillations in yaw that occur near the stall angle of attack. The purpose
of this project was to develop the capability for performing experiments in a water
tunnel to visualize the complex vortex flow fields of aircraft-like models undergoing
oscillations in roll. A forced-oscillation-in-roll apparatus was developed. The effects
of sweep angle, leading edge radius, oscillation amplitude and frequency, and angle
of attack were evaluated. Motion histories of the model and flow response were recorded
on video tape.
Phase I has demonstrated the feasibility and usefulness of water-tunnel flow visualization
and the forced-oscillation rig in investigating dynamic behavior such as wing-rock.
By carefully matching the frequency and amplitude of oscillation, the flow of a forced
wing oscillation closely resembles that of natural wing-rock. A forced oscillation
rig should also be more convenient to use in many experiments because of the readily
available phase reference from the forcing signal. Furthermore, wing-rock frequency
and amplitude are dependent on model parameters such as moment of inertia and bearing
friction; this often makes comparison between different experiments difficult. With
controlled oscillation, matching between two different models or model and actual
vehicle is
more achievable.
Potential Commercial Application:
Potential Commercial Application: Applications could be as an alternative control
system for new airplanes or, possibly, as a retrofit to existing aircraft. This study
also demonstrated the value of water tunnels as a research tool.
Project Title:
Performance Optimization for Rotors in Hover and Axial Flight
02.10-9282
Performance Optimization for Rotors in Hover
and Axial Flight
Continuum Dynamics, Inc.
PO Box 3073
Princeton, NJ 08543
Todd R. Quackenbush (609-734-9282)
ARC -- NAS2-12789
Abstract:
The rotorcraft community has a continuing need for improved design techniques for
hover and axial flight. Such techniques can be employed to best advantage if they
are coupled with numerical optimization methods to reduce the trial and error computations
when searching for configurations to meet particular design specifications. A new,
highly advanced, hover-performance analysis, EHPIC (Evaluation of Hover Performance
using Influence Coefficients), recently developed by the firm, seems well-suited
to the development of an optimization analysis. As a by-product of the solution method,
arrays of influence coefficients relating the rotor loads and wake geometry to the
down-wash are generated. These arrays are useful in the development of an optimization
scheme.
The Phase I effort demonstrated that a numerical optimization algorithm could be
coupled to the EHPIC code to produce rotors with substantially improved performance.
The coupling was accomplished by expanding the matrix of linear influence coefficients
in EHPIC to accommodate design variables and deriving coefficients for linear equations
governing perturbations in power and thrust. Using the rotor power as an objective
function and introducing constraints on the design variable perturbations, a sequential
linear optimization analysis was formed that was invoked to predict changes in the
twist distribution that produced reductions in power at constant thrust for a variety
of rotor configurations in hover and axial flight.
Potential Commercial Application:
Potential Commercial Application: Applications will be by researchers in the government
and rotorcraft designers in industry.
Project Title:
Zonal Method for Modeling Powered-Lift Aircraft Flow Fields
02.11-8060
Zonal Method for Modeling Powered-Lift Aircraft
Flow Fields
Amtec Engineering, Inc.
3055 112th Ave NE #208
Bellevue, WA 98004
Donald W. Roberts (206-827-3304)
ARC -- NAS2-12801
Abstract:
The need exists for a cost-effective three-dimensional flow analysis tool for modeling
the complex flow fields of powered-lift aircraft. This effort addressed the development
of a zonal method that couples a three-dimensional Navier-Stokes code to a potential
flow code based on panel methodology. The Navier-Stokes code is limited to viscous-dominated
zones such as impinging jets, ground vortices, separated flows, vectored nozzles,
etc. The potential flow code models the inviscid regions. Phase I resulted in a successful
coupling procedure. The results indicated that the interzone boundary placement influences
the overall convergence rate and that zonal solutions should be converged simultaneously
with the boundary conditions as opposed to converging these solutions to a low level
during each coupling iteration.
Potential Commercial Application:
Potential Commercial Application: The results of this work could be applied by aircraft
companies to design and evaluate powered-lift aircraft concepts.
Project Title:
Direct Computation of Turbulence Noise
02.12-7070
Direct Computation of Turbulence Noise
AeroChem Research Laboratories, Inc.
PO Box 12
Princeton, NJ 08542
Charles H. Berman (609-921-7070)
LaRC -- NAS1-18622
Abstract:
Direct computation of turbulence noise produced by jet engines is a logical application
for advanced computational fluid dynamics (CFD) programs run on supercomputers. Numerical
techniques for computing turbulence noise over a range of subsonic and supersonic
nozzle exit conditions would eliminate the highly empirical aspects of present noise
prediction techniques and enable study of advanced hypersonic propulsion systems.
Just as there are many CFD techniques, there are also many ways to determine the
acoustic field given the flow results.
Phase I focussed on the connection between CFD and aeroacoustic theory and on modifications
and improvements in CFD techniques needed for noise calculations. It evaluated the
computational potential for hypersonic flows and recommended specific computational
techniques for future development. Procedures were developed for extrapolating near-field
numerical pressure computations to the far field. Rules were formulated for the size
and shape of the computational domain to obtain accurate acoustic results. Methods
for numerically solving the time dependent Lilley equation were developed, and the
first known results were presented. A Mach number of 2 or greater was tentatively
chosen as the jet Mach number above which compressibility should be considered in
the noise source model.
Potential Commercial Application:
Potential Commercial Application: Applications are in noise control for civilian
aircraft such as the High Speed Civil Transport and the National Aerospace Plane.
A spinoff of the program will be improved numerical techniques for general, time-dependent
turbulent flows.
Project Title:
Analysis of Main-Rotor-Wake/Tail-Rotor Interaction Noise
02.12-9282
Analysis of Main-Rotor-Wake/Tail-Rotor
Interaction Noise
Continuum Dynamics, Inc.
PO Box 3073
Princeton, NJ 08543
Alan J. Bilanin (609-734-9282)
LaRC -- NAS1-18607
Abstract:
The importance of reducing the noise of the helicopter tail rotor has been recognized
for many years. However, both the prediction of tail rotor noise and the development
of low-noise designs have been impeded by a poor ability to simulate noise-generating
interactions between the main-rotor wake and the tail rotor. In many cases, even
the flight conditions leading to substantial interactions between the main-rotor
wake and the tail rotor have been difficult to determine. Recent advances in the
modelling of free-vortex wakes by the firm have generated tools that can generate
complete descriptions of the incident-vorticity field in the vicinity of the tail
rotor. In light of previous successes, it is anticipated that these tools can produce
a computational simulation capable of providing improved definition of interactions
between the main-rotor wake and the tail rotor and the resultant unsteady loads that
lead to strong acoustic emissions.
The Phase I effort successfully demonstrated that an advanced full-span model of
the main rotor wake could be incorporated in a novel scheme that permits high-resolution
descriptions of the tail rotor flow field to be reconstructed from preliminary, computationally
inexpensive simulations with coarse resolution.
Potential Commercial Application:
Potential Commercial Application: This analysis would aid rotorcraft designers in
meeting noise specifications for both civil and military helicopters and facilitate
research by government personnel in helicopter aero-acoustics.
Project Title:
Advanced Instrumentation for Aircraft Icing Research
03.01-8887
Advanced Instrumentation for Aircraft Icing
Research
Aerometrics, Inc.
894 Ross Drive, Suite 105
Sunnyvale, CA 94089
William D. Bachalo (408-745-0321)
LeRC -- NAS3-25348
Abstract:
The concern of this project is the need for instruments that can provide reliable
data on drop-size spectra and liquid water content in large-scale icing research
tunnels and airborne cloud measurements. Advanced laser-based diagnostics is the
thrust of this project, which investigated the possibility of utilizing the recently
developed phase Doppler particle analyzer (PDPA) in obtaining these data. Fiber-optic
probes are applied in order to make drop size distribution and liquid-water-content
measurements within the large scale (6'x 9') icing research tunnel and from aircraft.
Although fiber-optic links are compact, robust, and immune from electronic noise,
critical questions remain on coupling the laser beams into single-mode fibers and
maintaining alignment in a noisy, vibrational environment.
In Phase I, a basic fiber optic probe was evaluated in simulated aircraft icing
clouds. Comparisons of the measured drop size and velocity distributions, number-density,
and liquid water content made with the standard PDPA and the probe were in excellent
agreement. Preliminary testing in the NASA Lewis Icing Research Tunnel produced reasonable
results but revealed some problems with vibration and signal quality at high speeds.
Potential Commercial Application:
Potential Commercial Application: A reliable and tested means for obtaining data
on cloud drop sizes will have extensive applications in meteorology and aircraft
icing research, monitoring pollutant droplet emissions from power plants, scrubber
performance, and numerous other industrial applications.
Project Title:
Airborne Advance Warning of Air Turbulence
03.02-2150
Airborne Advance Warning of Air Turbulence
Turbulence Prediction Systems
4876 Sterling Drive
Boulder, CO 80301
H. Patrick Adamson (303-433-2150)
LaRC -- NAS1-18637
Abstract:
An innovative, operational, airborne, air-turbulence, advance warning system was
studied. It is a light-weight, low-power, passive, scanning, infrared optical instrument
with a state-of-the-art microprocessor. The basic instrument stems from NASA-sponsored,
airborne research on clear air turbulence (CAT) and low-level wind shear (LLWS).
The goal is to install the first pre-production system in an aircraft for initial
in-service testing. Microbursts and gust fronts, the major causes of LLWS, have a
distinctive temperature profile. This profile provides a basis for advance detection.
Using multiple IR wave bands, temperature close to the aircraft and up to five to
seven miles ahead of the aircraft can be ascertained.
Phase I explored the feasibility of using remote, passive, IR volumetric measurements
to provide advance warning of LLWS. The results obtained from testing of the instrument
in a simulated atmosphere (computer simulation with NASA-provided microburst LLWS
models) and ground testing of the prototype instrument demonstrated that the use
of IR represents a feasible method to provide advance warning of LLWS.
Potential Commercial Application:
Potential Commercial Application: Applications are for commercial and corporate aircraft
representing an existing market of more than 20,000 existing domestic units plus
foreign aircraft. The technology could also be used to detect other atmospheric conditions,
e.g. volcanic ash clouds and the jet stream, as a ground-based sensor either alone
or in conjunction with other sensors.
Project Title:
Aeronautical Human Factors Research
03.03-0660
Aeronautical Human Factors Research
Decision Science Consortium, Inc.
1895 Preston White Drive
Reston, VA 22091
Marvin S. Cohen (703-620-0660)
ARC -- NAS2-12795
Abstract:
Pilot judgment is a crucial ingredient in almost every aspect of commercial air
transport: safety, fuel efficiency, and passenger satisfaction. Effective introduction
into the cockpit of systems which support pilot judgments in important decisions
will require the development of display and interface designs based on an understanding
of pilot cognitive processes.
Phase I involved the development of hypotheses regarding pilot cognitive processes
and the design of preliminary cockpit displays that reflect those hypotheses. These
displays cater to preferred pilot decision-making strategies with regard both to
the balancing of competing objectives and to the handling of uncertainty. Phase I
proceeded in four steps: structured interviews of pilots, development of preliminary
prototype displays, evaluation and comments by pilots, and revision of the displays.
The aiding concepts developed were designed to help the commercial pilot make decisions
regarding potential changes in flight level, routes, or even destination in response
to a variety of factors. These concepts try to work with the pilot's preferred methods
of decision-making and his values and preferences. However, the aiding concepts attempt
to deal with decrements in pilot decision-making performance that could occur under
conditions of high stress.
Potential Commercial Application:
Potential Commercial Application: Commercial airlines are the major potential users
of this technology.
Project Title:
Electroencephalographic Monitoring of Complex Mental Tasks
03.03-2975
Electroencephalographic Monitoring of Complex
Mental Tasks
Center for NeuroDiagnostic Study, Inc.
275 Hospital Parkway, Suite 530
San Jose, CA 95119
Raul Guisado (408-281-4238)
LaRC -- NAS1-18625
Abstract:
The mental demands created by the increasing complexity of man-machine interactions
underline the need for rapid and non-invasive methods of monitoring the ability of
the human operator to handle increasingly large amounts of information and make rapid
decisions. Reports by others and current work done in the firm's laboratory suggest
that changes in electro- and rheo-encephalographic signals can be correlated to changes
in the complexity of a mental task. A study of the changes in electro- and rheo-encephalographic
parameters during mental tasks has been initiated in order to define discrete changes
predictive of increasing human mental workload.
The Phase I contract permitted development of a non-invasive system of monitoring
spatial patterns of neurophysiological changes during cognitive tasks and relating
these patterns to cognitive workload. The innovation is based on the integration
into a state-space model of neurophysiological and hemodynamic profiles to identify
mental state changes that occur during cognition. This approach incorporates electroencephalographic
information from the entire array of electrodes in order to reveal the evolving spatial
dynamics of the scalp electropotential field. In addition, it incorporates rheoencephalographic
assessment of intracranial hemodynamic changes as an additional dimension of this
spatial analysis.
Potential Commercial Application:
Potential Commercial Application: Potential commercial applications of the innovation
include: the development of non-invasive recording units for use in high mental-demand
environments; medical diagnostic applications for the assessment of abnormalities
of cognitive processing in a variety of disease states, such as brain injury, dementia,
neuro-rehabilitation, dyslexia, etc.; an aid in optimizing operator systems and work
profiles in private sector human engineering.
Project Title:
Integrated Design System for High-Altitude Long- Endurance Aircraft for Micro-Computers
03.04-9024
Integrated Design System for High-Altitude Long- Endurance Aircraft for Micro-Computers
David Hall Consulting
1113 Columbine Avenue
Sunnyvale, CA 94086
David W. Hall (408-248-4800)
ARC -- NAS2-12773
Abstract:
In recent years, increasing attention has been given in the aerospace industry
to the integration of aircraft design disciplines. This idea has been applied theoretically
to the design of sail planes for solar-powered, high-altitude, long-endurance (HALE)
aircraft and, more recently, for microwave-powered aircraft. These attempts at arriving
at integrated designs of one class of aircraft used then-existing, state-of-the-art
computer capabilities. No attempt was made to use new programming techniques derived
from artificial intelligence to develop more flexible systems for the conceptual
design of HALE aircraft.
The purpose of this project was to develop a general parametric sizing capability
for micro-computers using integrated design methodology. Design of a HALE aircraft
was used as a test case. This integrated design methodology incorporates some detailed
calculations and many qualitative rules-of-thumb and constraints which are not easily
quantified except by the accumulation of design experience. The system is currently
running on personal computers at the company, NASA, and the Georgia Institute of
Technology.
Potential Commercial Application:
Potential Commercial Application: This general aircraft sizing methodology, incorporating
a knowledge-based system for the design of high-altitude, long-endurance aircraft,
has application to other aircraft types. Non-aircraft applications may be possible
with further development.
Project Title:
Practical Application of Multivariable Robustness Methods to Advanced Aircraft Flight Control
03.05-2281
Practical Application of Multivariable Robustness
Methods to Advanced Aircraft Flight Control
Systems Technology, Inc.
13766 South Hawthorne Boulevard
Hawthorne, CA 90250
Peter M. Thompson (213-769-2281)
LaRC -- NAS1-18634
Abstract:
Much of the motivation for recent developments in general theory for assessing
robustness of linear, multi-variable, control systems comes from flight control system
(FCS) designs for aerospace vehicles which present the designer with many uncertain
and highly variable properties. For the assimilation of the new theories into "real
world" design, FCS designers will have to translate the theory into physical understanding.
Taking a distinctly different approach to bridge the gap between theory and practical
flight control design, this project combined singular-value and structured-singular-value
procedures with a literal (symbolic) development which leads to direct identification
of important aircraft dynamic and control system design parameters and their connections
with robust performance criteria. The work focused on practical flight control problems
expected to be encountered in air-breathing, hypersonic, high-angle-of-attack super-maneuverable
vehicles.
All of the project goals were met, and a number of surprises were uncovered. The
most notable arose from the comparison of a conventional and presumed highly robust
design where the latter exhibited superior robustness for some uncertainties and
very inferior robustness properties for uncertainties in aircraft parameters.
Potential Commercial Application:
Potential Commercial Application: The project outcome could find application in the
aircraft industry in the design and testing of advanced, highly integrated, flight
control systems. The techniques and procedures would be made widely available as
an extension of the firm's existing commercial control system design software.
Project Title:
Passive Electro-Optical Sensor Processing for Helicopter Obstacle Avoidance
03.06-8740
Passive Electro-Optical Sensor Processing for
Helicopter Obstacle Avoidance
Space Computer Corporation
2800 Olympic, Suite 104
Santa Monica, CA 90404
William B. Kendall (213-829-7733)
ARC -- NAS2-12774
Abstract:
The purpose of this project is to develop and demonstrate an innovative new computer
vision approach for mapping the three-dimensional region surrounding a moving vehicle
with passive electro-optical sensors. The primary application is for helicopter obstacle
avoidance. Until now, this has not been possible due to the lack of robust processing
techniques that can be implemented in real time within practical limitations on hardware
size, weight, power, and cost.
During Phase I the firm developed and successfully demonstrated an innovative, velocity
filter approach to passive ranging using complex natural-image scenes containing
illumination gradients, noise, occlusion, and other real-world artifacts. Furthermore,
this approach can be implemented with compact, low-cost hardware, and it is an effective
method for the determination of three-dimensional scene information from optical
imagery generated by a moving television camera. Those complex, real-world images
were processed in a robust manner through an extension of this method involving a
combination of image preprocessing and brightness continuity. The accuracy of depth
information obtainable with this new technique appears to be substantially greater
than that achieved by any other method thus far reported in the literature. For both
the lateral and forward motion cases, the experimental accuracy achieved approaches
the theoretical maximum as limited by the sensor resolution and the geometry and
appears to be more than adequate for helicopter obstacle avoidance and terrain clearance
purposes.
Potential Commercial Application:
Potential Commercial Application: Commercial applications include autonomous navigation
of robot vehicles, control of robot arms, detection and tracking of moving objects,
and passive ranging and vision for the blind.
Project Title:
Miniature Airborne Dew Point Sensor
03.07-0821
Miniature Airborne Dew Point Sensor
Niagara Scientific, Inc.
4004 New Court Avenue
Syracuse, NY 13206
Carl F. Fahrenkrug (315-437-0821)
LaRC -- NAS1-18623
Abstract:
The rapid, continuous measurement of relative humidity in fast-flowing gas streams
is a matter of a major concern not only for flight requirements, but also for many
industrial processes. While many methods exist at present, they all suffer limitations,
and there are no truly reliable instruments for measurements at either extreme humidity
or temperature. The instrument explored in this project should operate under a wide
range of humidity and temperature. It is expected to have a rapid response without
hysteresis. It is also expected to be immune to ambient effects such as acceleration
and temperature. It will be small in physical dimensions and require little energy
to operate.
Potential Commercial Application:
Potential Commercial Application: There is virtually no major industrial process
in which humidity is not an important parameter. The instrument developed under this
program will fill an important requirement in many of those processes and activities.
It would fit well in this company's interest in sensors and monitors.
Project Title:
Smart Angle-of-Attack and Angle-of-Sideslip Sensor
03.07-0905
Smart Angle-of-Attack and Angle-of-Sideslip
Sensor
Engineering Development Laboratory
11840 Canon Boulevard, Suite 500
Newport News, VA 23606
Richard E. Campbell (804-873-0905)
LaRC -- NAS1-18662
Abstract:
Virtually all flight vehicles require the accurate measurement of angle of attack
(alpha); those undergoing flight testing and some commercial and military aircraft
also make use of information on angle of sideslip (beta). Existing angle measurement
methods have limitations that make the measurement of alpha and beta impossible under
certain flight conditions. Some of these sensors have poor durability and can be
sensitive to the environment.
The concept studied in this project is intended to overcome these limitations. It
involves the use of miniature, solid-state transducers to detect changes in differential
mass flow as the flow angle varies. Included is a microprocessor used as an interface
to provide corrections and linearization of the output signal. Phase I consisted
of studies and concept verification using a two-dimensional model with a limited
number of variations in shape. Low-speed flow testing indicated sensitivity to the
shape of the instrument housing that requires further research.
Potential Commercial Applications: The proposed instrument could be used on all
types of operational military and commercial aircraft and for aeronautics research
and development flight testing.
Project Title:
Aircraft Flight Testing Techniques and Instrumentation
03.07-0979
Aircraft Flight Testing Techniques and
Instrumentation
North American Aerospace Corp.
PO Box 162284
Austin, TX 78716
Larry Bird (512-328-0979)
ARC -- NAS2-12741
Abstract:
The company's air flow analyzer (AFA) measures boundary-layer transitions and pressure
lines associated with laminar, transitional, and turbulent air flows associated with
airfoil, rotor blade, and propeller surfaces. The AFA has two distinct advantages
over existing flow analysis tools. First, it provides data from thousands of sense
points; second, it does not interfere with the natural laminar flow of the airfoil
surfaces. In addition, the light weight of the system should make it readily adaptable
to a variety of in-flight tests. Instrumentation was the primary emphasis during
Phase I, with the incorporation of new types of sensors. A demonstration using a
thin-film, ferro-electric, sensor array proved the practicability of using piezo-polymeric
devices to study boundary layer transition points and pressure lines. The real problem
is to correlate the raw data into meaningful data. This was partially addressed in
developing the algorithms for initial filtering of the raw data. It appears that
a practical, sensitive, boundary-layer-transition instrument is feasible with refinement
of the sensor array tested in this project. This system is now ready to be flight
tested to implement a practical new instrument for many air-data-collection applications.
Potential Commercial Application:
Potential Commercial Application: The applications are as a boundary layer detector
for wind tunnel and experimental aerodynamics, an air-data computer, and angle-of-attack
instruments.
Project Title:
Expert Systems for Real-Time Monitoring and Fault Diagnosis
03.07-3474
Expert Systems for Real-Time Monitoring and
Fault Diagnosis
Charles River Analytics Inc.
55 Wheeler Street
Cambridge, MA 02138
Alper K. Caglayan (617-491-3474)
ARC -- NAS2-12725
Abstract:
The major deficiencies in current real-time automatic fault diagnosis applications
for aerospace systems are the high rate of false alarms and the maintenance problems
caused by intermittent failures. The aim of this project is to demonstrate the use
of expert systems technology in improving the performance of current real-time avionics
monitoring and fault diagnosis applications and in designing new reconfigurable flight
control systems. In particular, the goal is development of a rule-set method allowing
a rule-based specification of the domain knowledge in these applications, development
of an expert system based on this specification, and integration of this compiled
knowledge into existing real-time monitoring and diagnosis solutions implemented
in conventional programming languages.
Phase I defined, designed, and developed a rule-set processor which retains the
desirable attributes of expert systems during the development state while producing
an efficient, conventional embedded code for real-time on-board expert system applications.
A prototype of the rule-set processor which allows the specification of topological
and procedural knowledge for time-critical applications has been implemented in the
Ada language.
Potential Commercial Application:
Potential Commercial Application: The results of this development of expert systems
technology have applications in new, real-time, fault diagnosis and monitoring systems
for aircraft and spacecraft.
Project Title:
Real-Time Modification of Structural Modes
03.07-4674
Real-Time Modification of Structural Modes
Systems Technology, Inc.
2672 Bayshore Parkway #505
Mountain View, CA 94043
Wayne F. Jewell (415-961-4674)
ARC -- NAS2-12726
Abstract:
The goal of this project was to improve a method of estimating, in a near-real-time
manner, modal frequencies and damping ratios of randomly excited aeroelastic vibrations
from flight test measurements. The estimation method operates without knowledge of
the random excitation, as well as with knowledge of a deterministic forcing function
applied to the aircraft through an excitation system. It is an adaptation of the
real-time non-intrusive parameter identification procedure developed by the firm
for the NASA Ames Research Center's Dryden Flight Research Facility.
The performance of the estimation method was documented by identifying the modal
frequencies and damping ratios of the modelled system both with and without knowledge
of the forcing function or input. With knowledge of the input, the method could accurately
identify both the frequency and damping ratio of the simulated modes as long as the
sampling frequency was properly chosen with respect to the modal frequency. The results
of applying the method without knowledge of the input show that it is possible to
identify accurately the frequency but the damping ratios were underestimated. The
model was applied to a limited amount of flight test data collected by NASA for the
F-18 aircraft.
Potential Commercial Application:
Potential Commercial Application: Real-time analysis of vibration and flutter tests
and real-time parameter identification, in general, would find applications in the
aerospace industry.
Project Title:
High-Performance, High-Temperature Heat Pipes
03.08-0236
High-Performance, High-Temperature Heat Pipes
Ultramet
12173 Montague Street
Pacoima, CA 91331
J. Grady Sheek (818-899-0236)
LaRC -- NAS1-18644
Abstract:
A reliable, efficient means for moving large amounts of heat from the source to
a heat sink will be required for thermal management systems in future aerospace applications
such as trans-atmospheric vehicles. The heat pipe is just such a device and, through
proper selection of the case material and working fluid, can operate nearly isothermally
from 5-2300 K. Heat pipes have been produced since the 1960's. This project, however,
addresses a unique and innovative method of producing seamless heat pipes utilizing
the process of chemical vapor deposition (CVD) and chemical vapor infiltration (CVI).
Since the resulting heat pipe will be seamless with the exception of the fill port,
it should have a high inherent reliability.
In Phase I, the process for making heat pipes was demonstrated. Vapor passages were
drilled through the thickness of reticulated carbon foam which was then infiltrated
with tungsten to provide the capillary wick structure. A tungsten wick is suitable
for most liquid metal working fluids. The porosity of the foam was then bridged
by CVD to create a wall over the part. The heat pipe was successfully tested using
methanol as a working fluid.
Potential Commercial Application:
Potential Commercial Application: This innovative heat pipe design will meet the
requirements of thermal management systems for future aerospace applications which
will have to be able to move massive amounts of heat and will require materials or
devices with high thermal conductivity.
Project Title:
Oxidation Resistant Ti/6Al/4V-SiC Composite Materials by Ion Implantation
04.01-6000
Oxidation Resistant Ti/6Al/4V-SiC Composite
Materials by Ion Implantation
Spire Corporation
Patriots Park
Bedford, MA 01730
James K. Hirvonen (617-275-6000)
LeRC -- NAS3-25326
Abstract:
Lifetime of silicon-carbide-reinforced, titanium-aluminum-vanadium composites at
high temperature is presently limited by oxidation and embrittlement to a few hours
or less. An oxidation inhibitor could increase this to more than 800 hours at temperature,
a time consistent with mission requirements for hypersonic vehicles such the National
Aerospace Plane. This project investigated the feasibility of extending the operating
temperature of these composites by ion implantation, which has previously been found
to significantly enhance the oxidation resistance of titanium.
The Phase I effort explored improving the oxidation resistance of Ti-6Al-4V alloy
at 540 C in air by ion implantation processing and using it in SiC-fiber, titanium
alloy composite structures. The plan was to use barium and other ions because previous
work by the principal investigator showed significantly improved oxidation resistance
in elemental Ti after implantation. These choices proved to be very difficult to
pursue due to the high secondary electron yield of Ba, which produced high-voltage
breakdown on the internal electrodes of the ion implanter.
Potential Commercial Application:
Potential Commercial Application: Extending the operating temperature of SiC-fiber-reinforced,
Ti-6Al-4V composites will open up a large number of applications such as aircraft
wing panels for hypersonic flight, compressor blades in advanced turbojet engines,
and turbine engine cases, spacers, and turbine disks.
Project Title:
Embedded Fiber Optic Sensors for Polymer-Matrix Composite Process Monitoring
04.01-7070
Embedded Fiber Optic Sensors for Polymer-Matrix Composite Process Monitoring
Geo-Centers, Inc.
7 Wells Avenue
Newton Centre, MA 02159
Ian Aeby (617-964-7070)
LeRC -- NAS3-25337
Abstract:
At present, confidence levels in the integrity of polymer-matrix, composite structures
are low due to uncertainties in process control during their manufacture. Control
of chemical changes during fabrication will require improved process parameter sensors
and control methodologies. The use of fiber optic sensors embedded within the composite
structure during fabrication was proposed as a means toward this end. Embedded sensors
offer improved data accuracy over remote sensors, and the small physical dimensions
of optical fibers minimize their impact on the mechanical properties of the finished
composite.
During the Phase I feasibility study, it was established that embedded fiber optic
sensors could be used to monitor critical composite process parameters such as temperature
and state of cure. Examples of these sensors were successfully embedded in various
composite layups. In addition, an interesting new referencing technique for intensity-modulated
sensors was discovered. While progress has been made in monitoring polymeric-matrix
composite fabrication processes, there is clearly much work to be done before the
value of an embedded fiber optic sensor system has been proven in a manufacturing
environment.
Potential Commercial Application:
Potential Commercial Application: Embedded fiber-optic pressure and temperature sensors
have applications in the commercial composite industry and, potentially, in medicine
for diagnostic instrumentation. Other possible uses are in environmental control
and monitoring performance of automobile engines.
Project Title:
Micro-Mechanical Model for Prediction of Failure Modes in Ceramic-Matrix Composites
04.01-7747
Micro-Mechanical Model for Prediction of Failure
Modes in Ceramic-Matrix Composites
Incubator Technologies, Inc.
800 West 14th Street, Suite 111
Rolla, MO 65401
Li Chai (314-364-7747)
LeRC -- NAS3-25333
Abstract:
The failure of ceramic-matrix composites is a complex phenomenon and differs from
the failure behavior of monolithic ceramics and polymeric composites. Prior studies
indicate that the growth of existing flaws in ceramic-matrix composites is not self-similar
and that substantial frictional slippage occurs at the fiber-matrix interface as
evidenced by large pull-outs. The improved fracture toughness for these composites
is largely due to these two energy dissipating mechanisms. The objective of this
project was to investigate the contribution of these two mechanisms.
A micromechanical analytical model based on the consistent shear-lag theory was
developed for predicting the failure modes in a fiber-reinforced, unidirectional,
ceramic-matrix composite. The model accounts for the relatively large matrix stiffness,
up to 100 percent of the fiber stiffness. The fiber and matrix stresses were established
as functions of the applied stress, crack geometry, and, most importantly, the microstructural
properties of the constituents and the fiber-matrix interface. The mode of failure
was established, and the role of microstructural properties on the failure mode,
ultimate strength, and the fracture toughness was assessed. A parametric study was
carried out using the model to establish regions of non-steady state cracking (stable
crack growth) in a unidirectional, ceramic-matrix composite.
Potential Commercial Application:
Potential Commercial Application: This work may lead to the optimization of ceramic
performance based on matrix and fiber properties for applications in aerospace propulsion
and primary structures, for example, on hypersonic transatmospheric aircraft.
Project Title:
Controlled Density Composite Carbide Structural Ceramics
04.01-9785
Controlled Density Composite Carbide Structural
Ceramics
Aker Industries, Inc.
952 57th Street
Oakland, CA 94608
Glendon M. Benson (415-658-7248)
LeRC -- NAS3-25406
Abstract:
This project explored an innovative and inexpensive process for producing composite
carbide ceramics reinforced with carbide fibers and measured the physical properties
of test samples so produced. The goal is to develop a process to tailor the matrix
properties through chemical means in order to produce optimum composite properties.
It is expected that this process will produce low-cost composite ceramic components
that exhibit higher fracture toughness and strength than exhibited by conventional
ceramics.
In Phase I, several hundred test specimens were prepared in which formulations and
processing parameters were varied according to the findings of previous research
to provide a range of physical properties. The processing steps varied were in mixing,
blending, aging, dispersing, curing, and pyrolyzing. Five resin formulations were
also included in these experiments. From this investigation, choices of the best
resins, fillers, dispersing agents, and processing variables can be deduced. Results
from Phase I indicate that high strength ceramic composites can be made to net shape
at low cost by the proposed process.
Potential Commercial Application:
Potential Commercial Application: Composite carbide ceramics have potential applications
for turbojet engines in the hot sections, heat exchangers, and structural components
requiring high hot strengths, wear and fatigue resistance, fracture toughness, benign
failure mode, and resistance to corrosive high-temperature environments.
Project Title:
Controlled CTE High-Performance Films for Space Structures
04.02-3200
Controlled CTE High-Performance Films for
Space Structures
Foster-Miller, Inc.
350 Second Avenue
Waltham, MA 02254
Richard W. Lusignea (617-890-3200)
LaRC -- NAS1-18636
Abstract:
Certain thermoplastic polyimides exhibit a combination of good processability and
excellent performance (chemical resistance and high mechanical, adhesive, thermo-mechanical
and thermo-oxidative properties) due to groups within the polymer which introduce
semi-crystalline character through thermal annealing. The combination of these qualities
overcomes the shortcomings of most commercially available high performance polyimides.
This program's objective is the development of film processing methods to orient
a semicrystalline thermoplastic film to improve and control the coefficient of thermal
expansion, fracture toughness, thermo-mechanical behavior, strength, and stiffness.
During the Phase I program, the firm applied innovative film processing and orientation
methods to LARC-CPI, a new semi-crystalline thermoplastic polyimide developed at
the NASA Langley Research Center. These methods successfully reduced the coefficient
of thermal expansion from 38 ppm/C to 16 ppm/C and showed that it could be further
reduced to less than 10 ppm/C. The project also showed that LARC-CPI can be processed
into high performance thermoplastic films with tensile strength and modulus over
300 mPa (44 Ksi) and 91.6 GPa (1.4 Msi), respectively.
Potential Commercial Application:
Potential Commercial Application: Potential applications will be for films used for
liners, vacuum bags, and encapsulation in the chemical process industry; for electronics
where high-density, surface-mounted, multi-chip modules require dimensional stability
in thin dielectric layers; and for spacecraft use as reflector substrates, solar
cell array panels, and self-deployable structures.
Project Title:
Development of Composite Structures with Enhanced Damage Tolerance
04.02-5325
Development of Composite Structures with
Enhanced Damage Tolerance
Textile Technologies, Inc.
2800 Turnpike Drive
Hatboro, PA 19040
Janice R. Maiden (215-433-5325)
LaRC -- NAS1-18628
Abstract:
The evolution of the aircraft industry has been characterized by a steady growth
in the use of lightweight materials strong enough to withstand the increasing demands
placed on today's high performance aircraft. However, these materials, such as graphite/epoxy
composites, suffer serious compression strength reductions as a result of impact
loads. The innovation addressed in this project solves this problem through the use
of advanced weave designs that allow for through-the-thickness reinforcement of multi-layer
graphite fabrics. This reinforcement provides a capability for the laminate to withstand
out-of-the-plane tensile loads induced by impact.
Design verification for small (6" x 36") laminate panels has been completed using
a loom to weave laminate plies and to stitch them together at the same time. The
next step is to scale-up the process to production size laminates (14" x 100 yards).
Alternate stitching materials--glass, Kevlar and graphite yarns--will also be investigated.
Multi-layer, through-the-thickness, laminate panels will be woven, infiltrated with
epoxy, and tested along side composites made of state-of-the-art laminates. By comparing
the damage area and strengths both before and after impact, it will be possible to
assess the value of inter-laminar strength and establish a design basis for an efficient
through-the-thickness weave. This project was not complete at the time this document
was prepared.
Potential Commercial Application:
Potential Commercial Application: Composite structures with enhanced damage tolerance
and reduced costs will be applicable in commercial and military aircraft as well
as in sporting goods, boats, automobiles, etc.
Project Title:
High-Temperature Turbine Blades
04.03-0236A
High-Temperature Turbine Blades
Ultramet
12173 Montague Street
Pacoima, CA 91331
John T. Harding (818-899-0236)
LeRC -- NAS3-25349
Abstract:
Iridium-coated, rhenium thrusters have been fabricated to net internal shape by
chemical vapor deposition (CVD) from the inside out. This program proposes to fabricate
coated, hollow, niobium turbine blades to net external dimensions by CVD on the inside
of a hollow mandrel conforming to the net external shape of the blade: an outside-in
process. An oxidation-resistant coating of silica, hafnia, or iridium would be applied
first, followed by a thick deposit of niobium or niobium alloy. This process ensures
the achievement of net shape for the coated blade; also, contamination of the niobium
at the interface, as a result of the coating deposition process and typically involving
oxygen, hydrogen, chlorine, or water, would be avoided. The resulting structure should
have an uncooled operating temperature capability of 1500 C or higher.
In Phase I, a method for forming iridium-coated, hollow niobium airfoils to net
shape by chemical vapor deposition was demonstrated. The iridium coating was shown
to provide oxidation protection to the niobium structure up to 1700 C.
Potential Commercial Application:
Potential Commercial Application: A practical manufacturing process for extending
the operating temperature of turbine blades has applications in military and commercial
jet engines as well as in spacecraft power systems.
Project Title:
Response of Rapidly-Solidified Ti Alloys to Thermochemical Treatment
04.03-6900B
Response of Rapidly-Solidified Ti Alloys to
Thermochemical Treatment
Universal Energy Systems, Inc.
4401 Dayton-Xenia Road
Dayton, OH 45432
Rabi S. Bhattacharya (513-426-6900)
LaRC -- NAS1-18620
Abstract:
The objective of this project was to develop titanium alloys with very fine microstructure
using rapid solidification and a thermochemical treatment employing hydrogen as a
temporary alloying element. In Phase I, the company investigated the microstructure
of rapidly solidified alloys of titanium with copper, boron, and carbon (Ti-4Cu,
Ti-1B and Ti-1C) before and after thermochemical treatment. This treatment showed
significant refinement of microstructure and precipitates in the case of Ti-4Cu.
Ti-1B showed promising results; however more work is necessary to optimize the parameters.
Ti-1C alloy did not respond positively to thermochemical treatment with hydrogen,
as indicated by an observed coarsening of the microstructure.
Potential Commercial Application:
Potential Commercial Application: A significant enhancement of mechanical properties
of Ti alloys would make them attractive for aerospace and other industrial applications.
Project Title:
Chemical Vapor Deposition of Ti-Al Foils
04.03-7648
Chemical Vapor Deposition of Ti-Al Foils
MSNW, Inc.
PO Box 865
San Marcos, CA 92069
George H. Reynolds (619-744-7648)
LaRC -- NAS1-18615
Abstract:
Effective use of intermetallic compounds in composite and honeycomb structures
will require high-strength, high-quality foils for starting materials. Direct fabrication
of titanium-aluminum (TiAl) foils by chemical-vapor deposition onto sacrificial tape
substrates was studied as a novel means to produced the desired starting materials.
Two techniques, high-temperature, chemical-vapor deposition from mixed halide vapors
and low-temperature, chemical-vapor deposition from mixed organometallic gases, were
explored. In Phase I, a cold-wall, chemical-vapor-deposition apparatus was constructed,
and TiAl alloy films ranging in composition from essentially pure Ti to approximately
TiAl3 and from 5-40 microns in thickness were successfully deposited on molybdenum
substrates. As characterized by optical and scanning electron metallographic examinations,
X-ray diffraction, microchemical analysis, and micro-hardness testing, the films
were found to be chemically homogeneous and generally dense although some films contained
isolated porosity and exhibited microcracks. Deposition was in agreement with the
predictions of a preliminary chemical process model constructed to describe the chemical-vapor
synthesis of TiAl films from halide precursors.
Potential Commercial Application:
Potential Commercial Application: The product foils could be useful in preparation
of thin-gage tapes and complex, honeycomb structures of difficult-to-work materials.
Other applications might include intermetallic-matrix composites for hypersonic vehicle
structural elements, advanced propulsion system components, and space structures.
Project Title:
An Expert System for Integrated Structural Analysis and Design Optimization
04.04-1319
An Expert System for Integrated Structural
Analysis and Design Optimization
Structural Analysis Technology, Inc.
4677 Old Ironsides Drive, #250
Santa Clara, CA 95054
Hasan Kamil (408-496-1120)
LeRC -- NAS3-25327
Abstract:
The purpose of this project was to explore the feasibility of an expert system
for integrated structural analysis and design optimization by answering questions
regarding data and computational requirements, architecture, and cost and by initiating
preliminary development.
In the Phase I research and development effort, an architecture and conceptual design
were developed for an integrated expert software for the structural design process
covering conceptual design work, iterative cycles of finite-element structural analysis
and design optimization, and detailed final design. The feasibility of this approach
was investigated, and a demonstration package with two expert software modules was
developed.
Potential Commercial Application:
Potential Commercial Application: The resulting expert software could be used by
NASA, other government organizations, and their contractors in designing aerospace
structures and vehicles with improved efficiency, reliability, and significant savings
in man-hours and costs.
Project Title:
Low CTE, Particulate-Reinforced Metal-Matrix Composite Material
04.05-1504
Low CTE, Particulate-Reinforced Metal-Matrix
Composite Material
DWA Composite Specialties, Inc.
21119 Superior Street
Chatsworth, CA 91311
Olin Hudson (818-998-1504)
JSC -- NAS9-17938
Abstract:
Joints and couplings for space structures require a low coefficient of thermal
expansion (CTE) while remaining light in weight and high in structural integrity.
They must also be easy to fabricate and low in cost. No material developed to date
adequately meets all of these criteria. The purpose of this project is demonstrating
and evaluating various low-CTE, particulate-reinforced, metal-matrix composites for
use as the construction material for these components. The approach is to combine
ultra-low-CTE reinforcements in selected low-CTE aluminum matrices aimed at producing
an isotropic composite material that exhibits a CTE of about 3 x10-6 in/in/F and
an ultimate strength >40 ksi.
Phase I efforts demonstrated that technology is available for producing very low-CTE
end fittings and other applications. Wide tailoring of mechanical and physical properties
is possible through judicious selection of matrix alloy, particulate composition,
size, volume fraction, and matrix reinforcement bond conditions. The relative usefulness
of analytical prediction of the CTE was also demonstrated for use as a guide in tailoring
key properties.
Potential Commercial Application:
Potential Commercial Application: The applications are in low-cost, stable (low-CTE),
light-weight space structures and components having high strength and stiffness,
no outgassing, and increased temperature capability.
Project Title:
Ultra-High Stiffness Net-Shape Tubular Space Structures
04.05-3200A
Ultra-High Stiffness Net-Shape Tubular Space
Structures
Foster-Miller, Inc.
350 Second Avenue
Waltham, MA 02254
Ted E. Kirchner (617-890-3200)
JSC -- NAS9-17940
Abstract:
Net-shaped tubular extrusions of solution-processed, ordered (liquid crystal) polymers
can be combined with inter-penetrating networks (IPNs) to produce tubular space structures
having ultra stiffness (40 Msi), near zero (less than 1 ppm/deg.C) coefficient of
thermal expansion (CTE), and low weight (1.56 gm/cc). The approach taken was to co-extrude
biaxially oriented (microfibrillar network), thin-walled poly p-phenyline benzolbisthiazole
(PBZT) tubing and, then, introduce a polyimide IPN, Thermid AL-600. The goals were
to achieve high axial stiffness through a nearly axial orientation of the PBZT molecules
in the inner tube and a low CTE through the combined effects of the more biaxial
orientation of the outer tube and the polyimide IPN. These materials would have superior
performance to aluminum and would be cheaper to fabricate than graphite-reinforced,
metal-matrix tubes.
The project was successful in extruding PBZT tubing with controlled orientation
and volume fractions of polyimide IPN. A zero CTE was bracketed but not achieved.
The bonding between the coaxial tubes during the post-cure processing was evident;
however, the high modulus was not reached for these tubes as had been demonstrated
for PBZT films and tubes in other projects. The difficulty in reaching a high modulus
is the result of processing problems.
Potential Commercial Application:
Potential Commercial Application: The primary application would be for space-based
structures fabricated from many tubular struts, truss members, and supports.
Project Title:
Filament Winding Process for Thermoplastic Matrix Composites
04.05-8900
Filament Winding Process for Thermoplastic
Matrix Composites
PDA Engineering
2975 Red Hill Avenue
Costa Mesa, CA 92626
Ronald Allred (714-540-8900)
MSFC -- NAS8-37632
Abstract:
Thermoplastic composites have high impact strength and higher solvent resistance
and can potentially be processed much faster than thermoset composites; however,
there is a lack of suitable processing techniques. To overcome this, a processing
method involving in-situ fusion and compaction during filament winding using an advanced
thermoplastic co-mingled with graphite fiber strands was investigated that used heat
for fusion from induced currents.
Exploratory experiments have shown that eddy current heating of graphite fibers
can be directed and confined to the interface bond line to achieve melt temperature
(about 400 C) in a thermoplastic matrix and form a solid structural composite. Compaction
of the fiber strands while the resin is molten can be accomplished through proper
design of a pressure application device that will conform to cross-overs and other
surface irregularities encountered in the filament winding process.
The tests conducted in the Phase I program show that induction heating can be used
to process graphite-thermoplastic composites on a continuous basis. Since the research
was conducted on the worst case of unidirectional composites, it may be possible
to process all types of fiber layups.
Potential Commercial Application:
Potential Commercial Application: Commercial applications of this technology include
manufacture and repair of aircraft skins, aircraft structures, vehicles, boats, spacecraft,
rockets, housing materials, and lightweight equipment.
Project Title:
Polymer with Biaxial Strength for Pyroelectric Applications
04.06-8200B
Polymer with Biaxial Strength for Pyroelectric
Applications
Chronos Research Inc.
4186 Sorrento Valley Boulevard
San Diego, CA 92121
Randall B. Olsen (619-455-8200)
GSFC -- NAS5-30270
Abstract:
A new method of electrical energy generation called pyroelectric conversion promises
to deliver power to spacecraft from a lightweight and inexpensive system. Pyroelectric
conversion may enable order of magnitude reductions in future launch and capital
costs for power systems.
The Phase I objective of providing a means for forming pyroelectric polymeric films
with mechanical properties superior to those of films previously available was successfully
accomplished. The enhanced mechanical properties of these films will greatly improve
the performance of pyroelectric generators, heat pumps, and refrigerators. An unexpected
immediate benefit of reaching the Phase I goal is that the pyroelectric conversion
performance of the active polymer was dramatically improved with respect to lifetime.
Because of the success of Phase I, the firm now has a method of fabricating durable
copolymer films hundreds of meters long, compared to the 3 cm limit of previous technology.
Potential Commercial Application:
Potential Commercial Application: In addition to their application in space power
systems, pyroelectric converters are expected to be an economical means to convert
low temperature heat into electrical energy in terrestrial systems at a capital cost
of less than one dollar per Watt.
Project Title:
Development of Specialized Floor Coverings for Launch Site Facilities
04.07-8371
Development of Specialized Floor Coverings for
Launch Site Facilities
Springborn Materials Science, Inc.
10 Springborn Center
Enfield, CT 06082
James P. Galica (203-749-8371)
KSC -- NAS10-11455
Abstract:
The existing floor materials at NASA launch site facilities, primarily in shuttle
assembly areas, have not been performing satisfactorily. Contamination arises from
outgassing of the plasticizers used in vinyl tiles and from chalking and dusting
of epoxy floor coverings.
The goal of this project is a conductive floor tiling material that has surface
and volume resistivities of 10 million ohm-cm. In addition, the floor covering will
be non-contaminating via out-gassing, resistant to hypergolic propellants and other
chemicals, non-flammable, non-dusting, and available in tile form. Other desirable
features include a light color, ease of installation, cleaning, and repair, low cost,
and resistance to impacts.
The objective of the Phase I effort was to formulate new floor covering compounds
that show feasibility for meeting the criteria for NASA's floor application but which
may still require further work in Phase II to formulate optimal compounds. Four resins
were selected for investigation: polyethylene, polypropylene, polybutylene and polyvinyl
chloride. Phase I demonstrated the feasibility of formulating such a suitable flooring
material using polymeric plasticized vinyl and flame-retardant polyethylene with
selected conductive fillers.
Potential Commercial Application:
Potential Commercial Application: Applications include floors for hospital operating
rooms, electronics laboratories, chemical processing plants, and photo laboratories.
Project Title:
Robotic Weld Path Programming
04.08-0960
Robotic Weld Path Programming
Mid-South Engineering, Inc.
3540 Dickerson Road
Nashville, TN 37207
Kristinn Andersen (615-865-0960)
MSFC -- NAS8-37629
Abstract:
For the application of robots to arc welding, constraints of weld position, weld
travel speed, and orientation of torch and wire guide (relative to each other and
relative to the joint) are considerations that must be dealt with in the path programming
task. The objective of this project is to demonstrate the feasibility of developing
algorithms for robotic, weld-path programming that are generic to any robot and positioning
system capable of accepting the kinematic transformation matrix, positioning system
axes, and velocity information from a host computer.
Key components of the proposed system were successfully developed, built, and demonstrated
in the Phase I research program. Investigation of commercial systems and other research
work was carried out, and the problems of welding using multiple robotic mechanisms
and redundant joints were addressed. A theory was developed into a formal algorithm,
coded in Fortran, and tested through simulations using equipment and work-piece models
from the Materials and Processes Laboratory at NASA-MSFC. The performance of the
algorithm was demonstrated by graphical simulations using the ROBOSIM package developed
jointly by NASA and Vanderbilt University.
Potential Commercial Application:
Potential Commercial Application: This innovation will be of significant value to
the commercial manufacturing industries for simplifying the task of programming multiple,
coordinated, robotic manipulators.
Project Title:
System Weld Control Through Expert Adaptive Interpretation
04.08-9955
System Weld Control Through Expert Adaptive
Interpretation
International Technical Associates (InTA)
2281 Calle de Luna
Santa Clara, CA 95054
Paul Lovoi (408-748-9955)
MSFC -- NAS8-37627
Abstract:
Automated welding has the potential to improve weld quality and reduce the scrap
rate. Numerically controlled (NC) welding can be successfully carried out using jigs
and fixtures to provide accurate positioning. Alternatively, adaptive, sensor-controlled
welding offers the promise of reduced tooling and part preparation costs, improved
quality, and reduced scrap rate over manual or NC welding. In addition, on-line quality
control of the weld can be implemented using the same sensors.
A rule-based expert system utilizing multiple sensors and a look-ahead capability
for real-time, adaptive welding was investigated in Phase I. This investigation conducted
welding tests using an available vision system designed to operate in a laser welding
environment on dark, nickel-based super alloys. Nonetheless, the vision system performed
well on the butt joint samples of the space shuttle aluminum external tank provided
by NASA. In almost every case the vision system software algorithms selected the
correct seam over near-by scratches. Modifications to the tracking software allowed
the system to detect and disregard tack welds and track on the remaining straight
seam. The plasma arc torch did not present an electro-magnetic interference problem
for the vision system or the electronics, but optical radiation from the arc was
significant. Two simple tests proved that more sophisticated filtering on a system
designed for plasma arc welding will eliminate any optical interference completely.
Potential Commercial Application:
Potential Commercial Application: Automated welding systems in automotive, aerospace,
and industrial manufacturing and repair environments will be able to use this system.
Welding system suppliers will integrate the system into their end products.
Project Title:
Methods for Evaluating the Predictive Accuracy of Structural Dynamic Models
04.10-2551
Methods for Evaluating the Predictive Accuracy
of Structural Dynamic Models
Engineering Mechanics Associates, Inc.
3820 Del Amo Boulevard, Suite 318
Torrance, CA 90503
Timothy K. Hasselman (213-370-2551)
JPL -- NAS7-1020
Abstract:
Large space structures, such as the NASA Space Station, which cannot be fully tested
in a ground test laboratory, require both ground testing and on-orbit identification
of as-built structures. This project addressed ground-testing procedures which are
critical to the success of on-orbit identification. Innovative methods for evaluating
and improving the predictive accuracy of structural dynamics models were investigated
during the Phase I study. This effort identified a new methodology for evaluating
uncertainties in mass, stiffness, and damping and how these propagate forward and
backward in order to evaluate the accuracy of response predictions and the uncertainty
in physical parameters.
Three different methods for propagating uncertain-ties--first order statistics,
fuzzy set theory, and Monte-Carlo simulation--were examined. An approach which combines
the first two appears to be an efficient, cost-effective approach for bounding the
level of modeling uncertainty. Key elements of the methodology were demonstrated
using a realistic model of the NASA Space Station "Block 1" configuration. Experimental
error due to substructure and sub-scale testing were simulated and compared using
the above methodology.
Potential Commercial Application:
Potential Commercial Application: Applications exist in all areas where analytical
models are relied upon to predict structural performance which cannot be directly
verified by testing. Examples include off-shore structures, nuclear power plants,
high-rise buildings, and numerous applications in the aerospace industry.
Project Title:
Reduced Weight Gondolas for Stratospheric Balloons
04.11-3200
Reduced Weight Gondolas for Stratospheric Balloons
Foster-Miller, Inc.
350 Second Avenue
Waltham, MA 02254
Joseph Boyce (617-890-3200)
JPL -- NAS7-1007
Abstract:
Stratospheric and research balloons carrying scientific instruments into the upper
atmosphere are very sensitive to payload weight. Reductions in balloon gondola weight
will allow a corresponding reduction in balloon volume required to reach a given
altitude and result in increased system reliability. Current gondolas are often open
frame structures of aluminum with sandwich panel platforms to support the instrument
and telemetry packages. Advanced composite materials with their high specific stiffness
and strength offer an opportunity to significantly reduce gondola weight. The greatest
benefit is derived by developing concepts and design approaches which are tailored
for composite materials to take full advantage of their high specific properties
while allowing for the unique designs necessary at joints and load introduction points.
The Phase I project has resulted in a lightweight gondola design made from advanced
composite materials. Current gondolas typically contribute one fourth of the total
system gross weight. This new gondola design is expected to account for one tenth
of the total system weight, with a corresponding increase in mission capability.
Potential Commercial Application:
Potential Commercial Application: The applications of a lightweight balloon gondola
are in research in the stratosphere.
Project Title:
Lightweight Advanced Composite Gondola for Stratospheric Balloons
04.11-8900
Lightweight Advanced Composite Gondola for Stratospheric Balloons
PDA Engineering
2975 Red Hill Avenue
Costa Mesa, CA 92626
Donald C. Guichard (714-540-8900)
GSFC -- NAS5-30286
Abstract:
This innovation would provide a versatile, modular gondola for stratospheric balloons
that employs a light-weight structural configuration which takes advantage of an
improved composite material. The proposed design configuration, validated by the
Phase I design assessments, has three primary composite structural components: a
payload module, a suspension module, and a payload floor panel, all joined by a pre-loaded,
circumferential band clamp.
These modules all employ a sandwich construction locally stiffened in critically
loaded regions. Design features provide flanges that can withstand the loads induced
when captured by the steel band clamp for assembly of the modules. The proposed joining
method was validated by the Phase I assessments.
Potential Commercial Application:
Potential Commercial Application: Applications are in a variety of balloon flight
missions and payloads.
Project Title:
Electrostatic Fractionation of Natural and Processed Lunar Solids in Space
04.12-8112
Electrostatic Fractionation of Natural and
Processed Lunar Solids in Space
Advanced Energy Dynamics
14 Tech Circle
Natick, MA 01760
Donald E. Heyburn (617-653-8112)
JSC -- NAS9-17928
Abstract:
This project explored the application of the firm's ultra-fine coal (UFC) electrostatic
separator technology for the separation and concentration of lunar-derived materials.
The innovation is in applying technology developed for use on earth to the vacuum
of space.
The Phase I effort showed that separation of lunar-derived minerals is technically
feasible and that the UFC separator may be a valuable tool in the recovery of minerals
from the space environment. Demonstrations included the separation of ilmenite from
basalt pulverized to 50% minus 50 micron and the separation of ice from pulverized
basalt on a UFC separator operating at -80 C. Theoretical analysis of the UFC separator
indicates that vacuum operation could greatly improve separator performance and capacity,
perhaps by a factor of 10 or more.
Potential Commercial Application:
Potential Commercial Application: The UFC separator can be used for dry separation
of many diverse solids including coal, talc, fly-ash, wheat flour, calcium carbonate,
and others. Vacuum operation is expected to be a space-only application, but the
theoretical understanding of the UFC separator in vacuum will greatly enhance terrestrial
performance.
Project Title:
Control Algorithm for Redundant Degree-of- Freedom Manipulators
05.01-0300A
Control Algorithm for Redundant Degree-of- Freedom Manipulators
Odetics, Inc.
1515 South Manchester Avenue
Anaheim, CA 92802
Steven M. Cohan (714-758-0300)
JPL -- NAS7-1006
Abstract:
Current manipulator control algorithms are often limited by their ability to resolve
singularities (when two or more joint rotation axes become aligned) as well as by
the inverse kinematics associated with six and higher degree-of-freedom (DOF) manipulators.
The goal of this project is to develop a control algorithm to drive a DOF arm while
keeping the arm's configuration away from avoidable singularities. The test-bed arm
for the project is one possible configuration of a modular, reconfigurable, redundant
arm being developed by the firm under an internal research and development program.
In the Phase I program, a control algorithm for a seven degree-of-freedom manipulator
was developed. This algorithm transformed six Cartesian command inputs into seven
joint command outputs while avoiding the manipulator's singularities. Phase I simulation
results also show that the algorithm's singularity avoidance feature improves arm
performance. With the singularity avoidance features inactive, the arm will move
close to or through singularities resulting in high joint velocity commands that
joint servos would not be able to track. With the singularity avoidance feature active,
the arm executes the commanded trajectories while avoiding these singularities. This
results in lower, achievable, and controllable joint velocities.
Potential Commercial Application:
Potential Commercial Application: The anticipated seven degree-of-freedom manipulator
will have applications in tasks where high strength, low weight, and human-like dexterity
are required. Commercial uses include nuclear facility maintenance and manufacturing.
Project Title:
Telepresence Sensor and Control Helmet
05.01-0300C
Telepresence Sensor and Control Helmet
Odetics, Inc.
1515 South Manchester Avenue
Anaheim, CA 92802
Timothy R. Larson (714-744-0300)
JPL -- NAS7-1019
Abstract:
The main purpose of this SBIR Phase I was to design a multi-purpose, telepresence
helmet that can easily adapt to many applications, including presence for telerobotic
control and display of three-dimensional, computer-generated images for "virtual
work station" applications. Along with multi-purpose capability, the helmet has a
wide field of view (180 degrees) and generates a "true" three-dimensional view by
accommodating and focusing to the viewer's area of interest. The helmet also has
a high resolution equal to that of the human eye (1 arc minute).
The Phase I study showed that it is feasible to build a helmet-mounted, wide-angle,
stereo display system that can match the biological performance of the human eye
in acuity, focus, and accommodation. Phase I research indicated that, for flexibility
of usage, the helmet system needs to be independent of the image source. This independence
was achieved in three steps. First, an intermediate image source was created. A helmet
system that uses this intermediate image as its source was designed. Second, transfer
equations to translate the real image source to the intermediate image were developed.
Finally, the digital electronics were designed to execute the transfer equations
at video rates (60 Hz) and then generate the displays to the intermediate image.
Potential Commercial Application:
Potential Commercial Application: This display system would have commercial applications
in the control of remote manipulators for nuclear power plants; underwater exploration
and inspection vehicles; and remote surveillance vehicles for security applications.
Project Title:
Spatial Planning for Mobile Articulated Vehicles and Dendritic Robotic Systems
05.01-0333
Spatial Planning for Mobile Articulated Vehicles
and Dendritic Robotic Systems
Scientific Research Associates, Inc.
50 Nye Road
PO Box 1058
Glastonbury, CT 06033
Alexander Y. K. Chen (203-659-0333)
JPL -- NAS7-1012
Abstract:
The new perspective of machine intelligence for multi-link, general-purpose manipulators
pursued in this project not only solves the inverse kinematic problem (IKP), but
also provides a potential self-correction mechanism to perform the assigned task.
The use of an IKP solving mechanism to determine the feasible motion trajectory either
by direct solution or with adequate modification is the basis for robot intelligence.
The unsolved decision-making procedure can be performed as teleoperation or automatic
planning. Due to the advantage of the decomposition technique, the articulation of
advanced robotic systems (e.g., redundant degrees of freedom and/or a reconfigurable
linkage structure) can be fully utilized.
A technique of implementing the spatial planning skill was developed and analyzed
in Phase I. The new IKP solving mechanism was activated on a Harris H700 mini-computer,
the computing system available to the company. Because the original software package
was incompatible with this computer, a new set of software was developed using FORTRAN
77. Specific emphasis was placed upon extending the original IKP solver to consider
mobile, dendritically configured robots.
Potential Commercial Application:
Potential Commercial Application: Areas such as material handling operations in hazardous
environments, outer space or deep sea explorations can take advantage of such advanced
robotic systems.
Project Title:
Neural Network Controller for Adaptive Movement in Robots
05.01-2215
Neural Network Controller for Adaptive Movement in Robots
Neurogen Inc.
325 Harvard Street, Suite 211
Brookline, MA 02146
Michael Kuperstein (617-739-2215)
LaRC -- NAS1-18639
Abstract:
The biggest challenges in controlling autonomous robots today deal with self-organization
of sensory-motor coordination, novelty in the working environment, and processor
faults. To meet these needs, a model of a prototype neural architecture for the dynamic
coordination of a multi-joint robot arm and two stereo cameras was investigated by
extending the previous static model into a dynamic model which will be able to generate
adaptive trajectories. With this system, a multi-joint robot arm could adaptively
reach targets in three dimensions in real time. The system would self-organize and
maintain visual-motor calibrations and would tolerate internal noise, partial system
damage, and changes in the mechanical and optical parameters of the robot as they
occur during wear.
Phase I work showed proof-of-concept that a neural-network controller can be simulated
on a computer to learn adaptive motor control from its own experience. The adaptive
controller can learn to generate accurate stable movements of a robot link without
information about link mass, link length, and direction of gravity and requiring
only vague information about payload and actuator limits. It can move a link carrying
an unforeseen payload from any starting joint angle to any ending point at a specified
duration without end point oscillations.
Potential Commercial Application:
Potential Commercial Application: The controller will find applications in novel
working environments because of its ability to deal with unforeseen changes in the
mechanical plant and actuators.
Project Title:
Telerobotic Rendezvous and Docking Vision System Architecture
05.01-2878
Telerobotic Rendezvous and Docking Vision
System Architecture
Triangle Research and Development Corp.
PO Box 12696
Research Triangle Park, NC 27709
Benjamin T. Gravely (919-467-2878)
GSFC -- NAS5-30292
Abstract:
The innovation defined in this project is a microcomputer-based, vision-system
architecture which allows a robot system to identify an object, determine its range
and orientation, and access explicit structural data on the acquired object for mating
with other objects.
In the Phase I effort, under controlled image conditions, computer algorithms were
developed to decode identification markings and to determine the range and orientation
of the target object to high accuracy The average execution time of 3.6 seconds
was greater than the program objective of 0.25 to 0.50 seconds because of slow data
transfer in the prototype system and the use of BASIC programming language. The procedures
were used on a robot to demonstrate the capture and placement of objects.
Potential Commercial Application:
Potential Commercial Application: Applications for autonomous or shared autonomous
operations are likely in space station operations, large-scale civil construction,
operations in hazardous environments (nuclear, underwater, fire fighting), identification
and retrieval of warehoused items and medical samples, and manufacturing components.
Project Title:
Telerobotic Digital Controller System
05.01-3319
Telerobotic Digital Controller System
The Navtrol Company, Inc.
9204 Markville Drive
Dallas, TX 75243
Richard J. Brown (214-234-3319)
GSFC -- NAS5-30283
Abstract:
The innovation addressed in this project is a small, light-weight, high capability,
multi-processor telerobotic controller system. The system consists of an interconnection
of several robotic joint controllers, end effector controllers, and a single master
controller communicating through a high-speed, serial communication bus. The master
controller controls communication with the various joint controllers in a time-multiplexed
manner and synchronizes their activity. Since the system is totally synchronized,
the time of occurrence for each measurement and controls application is known precisely
all through the system, allowing for compensation for any cross-coupling effects.
Both single and dual axis controllers can be developed. A single axis controller
would be about 3" x 4.24" and be almost totally self-contained. It will require only
28 V DC and a serial communication li