NASA Technical Reports Server (NTRS) 19930017216: Center for Space Construction Third Annual Symposium

322 Pages·8.1 MB·English

by  NASA Technical Reports Server (NTRS)

NASA-CR-192&88
UNIVERSITY OF COLORADO
AT BOULDER
CENTER FOR SPACE CONSTRUCTION
THIRD ANNUAL SYMPOSIUM
2.
3.
November 21 - 22, f991 "_"_ _a.2.._ ¢_.
(NASA-CR-192688) CENTER FOR SPACE N93-Z6405
CONSTRUCTION TH[RO ANNUAL SYMPOSIUM --THRU--
N93-26417
(Colorado Univ.) Z98 p
Unclas
G3/31 0159391

Dynamics of On-Orbit Construction Process 5/- !
K.C.Park
Thisstudy looks atthree aspects ofon-orbit construction: perturbationsof the orbiter due tochanges inconfiguration of the
structurebeing deployed, the effects of flexibility onthe dynamics of the orbiter and the deployed structure,and interaction
dynamics of the structuresbeingassembled. Oncethe interactiondynamics areunderstood, appropriate strategies forcontrol
and maneuvering ofmanipulators canbeformulated.
Interaction Dynamics and Control for Orbital Assembly
RenjengSu
Building structures and spacecTaftin orbit will require technologies for compliant contact of subassemblies. Satisfactory
compliant contacts must besecured forvarious joiningoperations to takeplace. Compliant interactions between mechanical
structuresmay bedefined bythedynamics ofpositionandcontactforces. Thebasicproblemhereishowtouseactiveandpassive
control mechanisms to achieve stable interactions and aspecified level of compliance. Results will bepresented on stability
analysis, compliance control design, andsteady-state contact dynamics specification.
Controls for Orbital Assembly of Large Space Structures
MarkBalas
To assemble large space structures,on-orbit control algorithms must deal with the berthing of flexible substructures while
maintaining stabilityandmeeting basicperformancegoals. No doubttheseoperations willbecarriedoutwith the aidofflexible
robot manipulators. Controlling suchcomplex dynamics willrequire reduced-order model-based algorithms forrapid response;
however, stabilityiseasily compromised by interaction with unmodeled dynamics. Analytical and numerical results will be
presented in three areas: the stableberthing of actively controlled substructures;direct model reference adaptive control of
distributed flexible structure models; and control design forflexible structures with slow actuatordynamics.
Structural Load Control During Construction
MartinMikulas
For many large space structures, the majordesign loads can occur during the construction phase or during subsequent
maintenance oraugmentation operationswhichinvolve moving largemasses. Intheabsenceof gravitationalloadings, allmajor
Ioadingson space structuresaretransientinnature,unlikethe traditionalstaticloadings associated with Earthstructures. This
factrequires theintroduction ofconcepts forstructuralelements designed toabsorbload impulses. This talkwillpresentanew
strutconcept fora"fuse"inthe structurewhichcanrelease atprescribedlevels ofloading and return tothe nominal position at
acontrolled rate afterthe loading haspassed. Adiscussion ispresented of thegeneral application ofthe strutto several space
structures, including the recent SpaceShuttle thrusterpressure blaston the SpaceStationsolar arrays.
Systems Engineering Studies of On-Orbit Assembly Operations
GeorgeW.Morgenthaler
Systems engineering studies oforbitalassembly operations atCSCfocus onthe issues ofsubassembly partitioning, packaging
and delivery to LEO,cost trade-offs, operation simulation, analysis ofinterruptabilityand constructibility, andexpert systems
forconstruction sequence planningand evaluation. Asimplified cost trade-off model will bepresented which relates size of
Heavy LaunchLiftVehicles, number ofsubassemblies tobedelivered toLEO,andthe probability ofmission success.
Expert Systems for Assembly Sequence Evaluation
SteveJolly
Complexity of orbital assembly will ultimately stem from the actual physical properties and behavior of the delivered
subassemblies. Toreduce thiscomplexity itisdesirabletolaunch the largest possible pre-integrated, pre-assembled, pre-tested
subassemblies, while simultaneously conforming to launch vehicle, construction tool and resource constraints. A simulation
model which combines numerical and symbolic engineering knowledge with heuristicreasoning willbe presented. The main
function ofthismodel istodecompose arepresentative SEI"Phase A"spacevehicle intodeliverable orbitalsubassemblies. The
model employs state-of-the-art constraint propagationtechniques developed atStanfordUniversity forterrestrialconstruction
tocreatea potentially powerful space research tool. Simulationresults will be presented.
Lunar Regollth and Structure Mechanics
SteinSture
Lunar regolith is unlike terrestrial unconsolidated soils. Its unusual strength and stiffness properties simplify design and
construction ofembankments, shielding structures andfoundations, butmake itmoredifficult toperform excavations andcuts
thanon Earth. Inthis presentation we focus on construction ofregolith-structure facilities, and characteristicsof scale-model
experiments. Fundamental mechanical properties ofregolith and density variationson the lunarsurface arealsodescribed.
Indigenous Lunar Construction Materials
WayneRogers
The utilization of local resources for the construction and operation of a lunar base can significantly reduce the cost of
transporting materials and supplies from Earth. The present study is an investigation of the feasibility of processing lunar
regolith toform construction materials andstructuralcomponents. Ascenariowill bepresented whichintegrates a processing
method withthe design foralunarbaseshelter and potential construction techniques.
Design Concepts for Pressurized Lunar Shelters Utilizing Indigenous Materials
JohnHappel
Twodesign concepts for pressurized lunarsheltersarepresentedtogether with anin-depth analysis ofprimary and secondary
load conditions and arguments forthe utilization of cast basalt as the principal construction material. The first design is
comprised ofcast cylindrical segments which arepost-tensioned in thelongitudinal direction. The second design isbasedon
arch-slabs and post-tensioned ring girders which arealso post-tensioned longitudinally to create a structure dominated by
compression. Construction sequences are outlined forrapid assembly of the two pressurized shelters.
Configuration Optimization of Space Structures
CarlosFelippa
The suitability of Kikuchi's homogenization method for the configuration-shape-size optimization of space structures is
investigated. A "design domainblock"filledinitially withfiniteelements isgradually"sculpted" intoanoptimalstructure. This
new method promises to bea powerful tool in helping the conceptual designer. We focus on itsapplication to planetary
structures.
Telerobotic Rovers for Extraterrestrial Construction
JimAvery
Roboticrovers willplayacrucialrole inextraterrestrialconstruction. They will substitute forhumans inmany operations such
assurveying, sensing, signaling and loadhandling. Roversystems must be versatilesothattheycanperform awide variety of
jobs, and robust to parts failures. To this end, the ideas of software modularity and multi-robot coordination are being
investigated. The current focuses include the development ofthree telerobotic platforms, infrared positioning systems, anda
4-degree-of-freedom manipulator. Design concepts and telerobotic development willbepresented.
Lunar Surface Structural Concepts and Construction Studies
MartinMikulas
Apreliminary design foraheavy liftcranecapableofpositioning 30,000kgmasses onthesurfaceofthemoon willbepresented.
Thiscrane will enableremote orautonomous precisionpositioning oflarge masses without the manualaidof astronauts. The
craneconcept makes useofthreecablesinsteadofonetomaintain positive, precisecontrolofthepayload. Thepresentation will
include cranemass, stiffness, and control,and will describe an ongoing experimental program toevaluate the concept.
Agenda
Center for Space Construction - Third Annual Symposium
University of Colorado, Boulder
November 21 & 22, 1991
November 21, 1991 Coors Events/Conference Center, Rooms 3 & 4
7:45 - 8:10 Registration
8:10 - 8:15 Welcome A. Richard Seebass, Dean of Engineering
8:15 - 8:45 Introduction Renjeng Su, CSC Director "u
8:45 - 10:00 Orbital Construction
K.C. Park
Dynamics of On-Orbit Construction Process 1
Interaction Dynamics and Control for Orbital Assembly _' Renjeng Su
Controls for Orbital Assembly of Large Space Structures :_ Mark Balas
10:00 - 10:15 break
10:15- 12:05 Orbital Construction (continued)
Martin Mikulas
Structural Load Control During Construction. -', ._
Systems Engineering Studies of On-Orbit Assembly Operations George Morgenthaler
Expert Systems for Assembly Sequence Evaluation -6 Steve Jolly
Assembly and Joining Methods for Large Space Structures Harold Bush, NASA
12:05 - 1:15 lunch and poster session
1:15 - 3:15 Lunar Construction
Lunar Regolith and Structure Mechanics-7 Stein Sture
Indigenous Lunar Construction Materials- _ Wayne Rogers
Design Concepts for Pressurized Lunar Shelters - John Happel
Configuration Optimization of Space Structures -; _ Carlos Felippa
3:15 - 3:30 break
3:30 - 5:00 Lunar Construction (continued)
Telerobotic Rovers for Extraterrestrial Construction -// Jim Avery
Lunar Surface Structural Concepts and Construction Studies -i _-- Martin Mikulas
Robotic Technology Application Plan for JSC t.. ",' ...... Reg Berka, NASA
5:00 - 5:15 Summary Renjeng Su
5:15 - 7:00 Wine/Cheese Reception and Poster Session
November 22, 1991 Engineering Center
Meet atMain Lobby
8:00 - 10:00 Experimental and Simulation Demonstrations
Lunar Crane Testbed
Lunar Regolith and Structures
Lunar Rover and Local Positioning System
Dynamics of Orbital Structures
Expert Systems for Assembly Sequence Evaluation

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