Aircraft
Landing Gear Loads Simulation : for B. J. Brock Associates of Dallas, in behalf of Gates
Learjet of
Wichita (Jan '82 thru Apr '82).
In the
performance of this contract, I derived the equations defining a 6 degree of
freedom aircraft landing simulation including a complete oleo-pneumatic shock
strut and tire simulation. The
strut included a compressible oil hydraulic model (with metering pin), adiabatic pneumatics, and un-sprung mass degrees of freedom
(including tire spin up and cornering effects). The landing carriage analysis was completely general in that
all dynamic coupling effects between stroking of the un-sprung mass and
airframe motion were included.
Since this analysis was to be incorporated into an existing elastic
airframe simulation, I designed an
interface specification that allowed the gear programs to be written and
checked-out independently, then be simply integrated with the client's elastic
airframe simulation. Fortran programs
were developed on my own computer, then delivered electronically (not a common
practice at that time) to the clients' VAX 11/780 in Wichita and Cyber 176 in Houston, saving the
client significant computing and travel costs.
Performance Measurement of Compiler in Avionics Environment: for Intermetrics of Boston/Seattle in behalf of Boeing Aircraft of Seattle (Feb '82
thru May '82).
This
task required the development of a tool to test the performance of a high level
language compiler (Jovial) targeted for an avionics computer environment. All aspects of the compiler were to be
tested (from reliability to executional efficiency). Specification of techniques to test the compiler attributes
and an overall executive design for a benchmark and data management tool were
accomplished. The design allowed
for systematically testing the compiler in the context of an emulated, as well
as an actual hardware avionics environment. Also included was the specification for modeling the
language's utilization in its avionics environment. Although Boeing' Air Force contract
(stimulating this work) was cancelled, this design was found to have intrinsic
value, and was eventually
implemented by a Boeing sub-contractor for its own use.
Hydro-Electric
Turbine Blade Process Controller Software Design: for Seawell Manufacturing of Seattle in behalf of The Army
Corps of Engineers
(Jul '82 thru Dec '82).
I was
first retained by Seawell in a
project engineering capacity, with sole responsibility for preparation
of a competitive proposal to be submitted by Seawell to the client (a large
hydro-electric project on the Columbia river). Upon Seawell's winning this contract, they retained me to
design, program, and operationally verify the on-line process control system. I accomplished a top-down design of the
real time digital controller to: sense analog signals pertinent to turbine
performance (such as reservoir pool level, gate opening, etc.), determine
optimal blade angle setting for the hydro-electric turbine, then command and follow-up control of
the blade angle positions. As a
safety critical system, fail-safe features, reasonableness testing, and a
portable CRT terminal based unit-self-diagnosis capability were incorporated into the design. I then implemented the design using
6502 microprocessor assembly language.
My role as project engineer included critical path analysis scheduling,
and pre-shipment verification of the units. I also provided
complete top-down design documentation, and a field user manual for the units.
Space
Tether Engineering: for over
20 Aerospace Companies and Government agencies ('83 up to the present).
See
details in Tether Qualifications resumeÕ.
Space
Shuttle Tether Analysis Design System: Done for McDonnell Douglas Aircraft, in behalf of the NASA
Johnson Space Center
of Houston (Feb '83 thru Apr '87).
The
original intent of this contract was to provide an existing Shuttle flight
simulation with the capability of incorporating a tethered object into its
dynamical environment for upcoming mission verification. In the execution of this task, I
suggested that a more general approach would have minimal development impact,
and could result in a formidably general tethered dynamics simulation
system. This philosophy gave birth
to an extensive software system that has become known as GTOSS (Generalized Tethered
Object Simulation
System). This system simulates the orbital and
interactional dynamics of an arbitrary number of objects (mixed 3 or 6 degree
of freedom), connected through
arbitrary attach points by an arbitrary number of tethers. The tethers can be massless, or possess distributed mass (as a mix of either bead or modal synthesis models), and can experience
distributed aerodynamic and electrodynamic forces (If they carry current in the
earth's magnetic field). The
tethers can be connected to
objects in arbitrarily complex fashion.
Through a rigorously defined interface specification, this software system is also designed to be
easily integrated into any existing dynamical simulation, thus providing that
simulation with a host of tethered objects in its environment. The GTOSS system has been procured by
over 20 government and private
sector engineering organizations.
Space
Shuttle Tether Analysis Design System: Done for Lockheed Aircraft, in behalf of the NASA
Johnson Space Center
of Houston (May '87 thru '96).
This is
a continuation of the previous work on GTOSS. Major tasks accomplished in this phase include the
development of a complete 3-Dimensional animation movie capability for the
engineering display of arbitrarily complex tethered system solutions on the
Macintosh computer, and an automated re-certification system for verification
of GTOSS software modifications. The GTOSS simulation lead the way for industry-wide
tether model validation and became the official baseline simulation for NASA's
final certification of Shuttle tether flights. During this contract phase, I
was employed at the NASA Houston Mission Control Center as a tether expert to
support the international Italian
Tethered Satellite System (TSS) experiments on Shuttle flights STS-46 ('92) and
STS-75 ('96).
Launch
Abort Dynamics Analysis: Done
for Blue Origin, LLC of Seattle, WA
(Ô2004 up to the present).
The
effort has been accomplished for the private space travel company created by
the originator of ÒAmazon.comÓ. This has been a series of new configuration explorations using a 6 degree of freedom simulation (GTOSS)
of a launch abort vehicle. Full degree of freedom aerodynamic models were coded
for the rigid body model which was then subjected to various wind profiles and abort conditions to produce
assessments of full axis control requirements that might be anticipated to
maintain a desired reentry attitude following launch abort.
Forest
Logging System Development Done for Skyder, LLC of British Columbia (Ô2006 up to the
present).
This
work consists of the dynamic simulation of a complex arrangement of tethers
held aloft by a lifting element
(balloon) to perform minimum environmental-impact
logging. A total of 27 tethers and 10 objects are involved in this simulation.
Differential line deploy/retrieval control algorithms are being devised to
demonstrate preliminary feasibility of this scheme, and develop engineering understanding
of the critical design parameters that may need to be considered during actual
design and implementation of the concept. Controlled traverse scenarios are conducted under various topographical
environments and combinations of winds and gusts, including transient effects
of log loading and un-loading.