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At least 721 records · Page 40

The Design, Planning and Control of Robotic Systems in Space

In the future, robotic systems will be expected to perform important tasks in space, in orbit and in planetary exploration. In orbit, current technology requires that tasks such as the repair, construction and maintenance of space stations and satellites be performed by astronaut Extra Vehicular Activity (EVA). Eliminating the need for astronaut EVA through the use of space manipulators would greatly reduce both mission costs and hazards to astronauts. In planetary exploration, cost and logistical considerations clearly make the use of autonomous and telerobotic systems also very attractive, even in cases where an astronaut explorer might be in the area. However, such applications introduce a number of technical problems not found in conventional earth-bound industrial robots. To design useful and practical systems to meet the needs of future space missions, substantial technical development is required, including in the areas of the design, control and planning. The objectives of this research program were to develop such design paradigms and control and planning algorithms to enable future space robotic systems to meet their proposed mission objectives. The underlying intellectual focus of the program is to construct a set of integrated design, planning and control techniques based on an understanding of the fundamental mechanics of space robotic systems. This work was to build upon the results obtained in our previous research in this area supported by NASA Langley Research Center in which we have made important contributions to the area of space robotics.

Dubowsky, Steven↗

Ranging Apparatus and Method Implementing Stereo Vision System

A laser-directed ranging system for use in telerobotics applications and other applications involving physically handicapped individuals. The ranging system includes a left and right video camera mounted on a camera platform, and a remotely positioned operator. The position of the camera platform is controlled by three servo motors to orient the roll axis, pitch axis and yaw axis of the video cameras, based upon an operator input such as head motion. A laser is provided between the left and right video camera and is directed by the user to point to a target device. The images produced by the left and right video cameras are processed to eliminate all background images except for the spot created by the laser. This processing is performed by creating a digital image of the target prior to illumination by the laser, and then eliminating common pixels from the subsequent digital image which includes the laser spot. The horizontal disparity between the two processed images is calculated for use in a stereometric ranging analysis from which range is determined.

Li, Larry C.↗

The Design, Planning and Control of Robotic Systems in Space

In the future, robotic systems will be expected to perform important tasks in space, in orbit and in planetary exploration. In orbit, current technology requires that tasks such as the repair, construction and maintenance of space stations and satellites be performed by astronaut Extra Vehicular Activity (EVA). Eliminating, the need for astronaut EVA through the use of space manipulators would greatly reduce both mission costs and hazards to astronauts. In planetary exploration, cost and logistical considerations clearly make the use of autonomous and telerobotic systems also very attractive, even in cases where an astronaut explorer might be in the area. However, such applications introduce a number of technical problems not found in conventional earth-bound industrial robots. To design useful and practical systems to meet the needs of future space missions, substantial technical development is required, including in the areas of the design, control and planning. The objectives of this research program were to develop such design paradigms and control and planning algorithms to enable future space robotic systems to meet their proposed mission objectives. The underlying intellectual focus of the program is to construct a set of integrated design, planning and control techniques based on an understanding of the fundamental mechanics of space robotic systems. This work was to build upon the results obtained in our previous research in this area supported by NASA Langley Research Center in which we have made important contributions to the area of space robotics. This program was proposed and accepted as a three year research program, a period of time necessary to make the type of fundamental developments to make a significant contributions to space robotics. Unfortunately, less than a year into the program it became clear that the NASA Langley Research Center would be forced by budgetary constraints to essentially leave this area of research. As a result, the total funding we received under this grant represented approximately one year of the original, proposed and approved, funding. For some time, there was substantial uncertainty that even this very reduced level of funding would be provided. The spending of the reduced available funds was spread just over two years to provide the support to permit the MS students who had joined the program to receive their master's degree and terminate their studies in this area.

Dubowsky, Steven↗

EVA Roadmap: New Space Suit for the 21st Century

New spacesuit design considerations for the extra vehicular activity (EVA) of a manned Martian exploration mission are discussed. Considerations of the design includes:(1) regenerable CO2 removal, (2) a portable life support system (PLSS) which would include cryogenic oxygen produced from in-situ manufacture, (3) a power supply for the EVA, (4) the thermal control systems, (5) systems engineering, (5) space suit systems (materials, and mobility), (6) human considerations, such as improved biomedical sensors and astronaut comfort, (7) displays and controls, and robotic interfaces, such as rovers, and telerobotic commands.

Yowell, Robert↗

Human Exploration of Mars: The Reference Mission of the NASA Mars Exploration Study Team

The Reference Mission was developed over a period of several years and was published in NASA Special Publication 6107 in July 1997. The purpose of the Reference Mission was to provide a workable model for the human exploration of Mars, which is described in enough detail that alternative strategies and implementations can be compared and evaluated. NASA is continuing to develop the Reference Mission and expects to update this report in the near future. It was the purpose of the Reference Mission to develop scenarios based on the needs of scientists and explorers who want to conduct research on Mars; however, more work on the surface-mission aspects of the Reference Mission is required and is getting under way. Some aspects of the Reference Mission that are important for the consideration of the surface mission definition include: (1) a split mission strategy, which arrives at the surface two years before the arrival of the first crew; (2) three missions to the outpost site over a 6-year period; (3) a plant capable of producing rocket propellant for lifting off Mars and caches of water, O, and inert gases for the life-support system; (4) a hybrid physico-chemical/bioregenerative life-support system, which emphasizes the bioregenerative system more in later parts of the scenario; (5) a nuclear reactor power supply, which provides enough power for all operations, including the operation of a bioregenerative life-support system as well as the propellant and consumable plant; (6) capability for at least two people to be outside the habitat each day of the surface stay; (7) telerobotic and human-operated transportation vehicles, including a pressurized rover capable of supporting trips of several days' duration from the habitat; (7) crew stay times of 500 days on the surface, with six-person crews; and (8) multiple functional redundancies to reduce risks to the crews on the surface. New concepts are being sought that would reduce the overall cost for this exploration program and reducing the risks that are indigenous to Mars exploration. Among those areas being explored are alternative space propulsion approaches, solar vs. nuclear power, and reductions in the size of crews.

Connolly, John↗

Return to the Moon: A New Strategic Evaluation

This paper reviews the value of a new lunar program, initially robotic and eventually manned, in the light of developments since the 1991 Synthesis Group study of the Space Exploration Initiative. The objective is to evaluate a return to the Moon in comparison to proposed Mars programs as a focus for American space exploration with humans in the next century. The Moon is demonstrably accessible, hospitable, useful, and interesting. Lunar programs are inherently faster and less risky from a programmatic viewpoint than comparable Mars programs such as Mars Direct. The dominant reason for a resumption of manned lunar missions, focussed on a single site such as Grimaldi, is to rebuild the infrastructure for missions beyond earth orbit, the last of which was in 1972. A transitional program, corresponding to the 10 Gemini missions that bridged the gap between Mercury and Apollo, was considered absolutely essential by the Synthesis Group. Further justification for a return to the Moon is the demonstrated feasibility of a robotic lunar observatory, concentrating on optical and infrared interferometry. Many unsolved scientific questions about the Moon itself remain, and could be investigated using telerobotic lunar rovers even before the return of humans. Mars is unquestionably more interesting scientifically and far more hospitable for long-term colonization. A new lunar program would be the most effective possible preparation for the human exploration, settlement, and eventually the terraforming of Mars. Lunar and Mars programs are complementary, not competitive. Both can be justified in the most fundamental terms as beginning the dispersal of the human species against uncontrollable natural disasters, cometary or asteroidal impacts in particular, to which mankind is vulnerable while confined to a single planet. Three specific programs are recommended for the 2001-2010 period: Ice Prospectors, to evaluate polar ice or hydrogen deposits; a robotic lunar observatory; and a manned lunar base and observatory.

Lowman, Paul D., Jr.↗

Return to the Moon: A New Strategic Evaluation

This paper reviews the value of a new lunar program, initially robotic and eventually manned, in the light of developments since the 1991 Synthes Group study of the Space Exploration Initiative. The objective is to evaluate a return to the Moon in comparison to proposed Mars programs as a focus for American space exploration with humans in the next century. The Moon is demonstrably accessible, hospitable, useful, and interesting. Lunar programs are inherently faster and less risky from a programmatic viewpoint than comparable Mars programs such as Mars Direct. The dominant reason for a resumption of manned lunar missions, focused on a single site such as Grimaldi, is to rebuild the infrastructure for missions beyond Earth orbit, the last of which was in 1972. A transitional program, corresponding to the 10 Gemini missions that bridged the gap between Mercury and Apollo, was considered absolutely essential by the Synthesis Group. Further justification for a return to the Moon is the demonstrated feasibility of a robotic lunar observatory, concentrating on optical and infrared interferometry. Many unsolved scientific questions about the Moon itself remain, and could be investigated using telerobotic lunar rovers even before the return of humans. Mars is unquestionably more interesting scientifically and far more hospitable for long-term colonization. A new lunar program would be the most effective possible preparation for the human exploration, settlement and eventually the terraforming of Mars. Lunar and Mars programs are complementary, not competitive. Both can be justified in the most fundamental terms as beginning the dispersal of the human species against uncontrollable natural disasters, cometary or asteroidal impacts in particular, to which mankind is vulnerable while confined to a single planet. Three specific programs are recommended for the 2001-2010 period: Ice Prospectors, to evaluate polar ice or hydrogen deposits; a robotic lunar observatory; and a manned lunar base and observatory.

Lowman, Paul D., Jr.↗

Life Sciences Division Spaceflight Hardware

The Ames Research Center (ARC) is responsible for the development, integration, and operation of non-human life sciences payloads in support of NASA's Gravitational Biology and Ecology (GB&E) program. To help stimulate discussion and interest in the development and application of novel technologies for incorporation within non-human life sciences experiment systems, three hardware system models will be displayed with associated graphics/text explanations. First, an Animal Enclosure Model (AEM) will be shown to communicate the nature and types of constraints physiological researchers must deal with during manned space flight experiments using rodent specimens. Second, a model of the Modular Cultivation System (MCS) under development by ESA will be presented to highlight technologies that may benefit cell-based research, including advanced imaging technologies. Finally, subsystems of the Cell Culture Unit (CCU) in development by ARC will also be shown. A discussion will be provided on candidate technology requirements in the areas of specimen environmental control, biotelemetry, telescience and telerobotics, and in situ analytical techniques and imaging. In addition, an overview of the Center for Gravitational Biology Research facilities will be provided.

Yost, B.↗

Return to the Moon: A New Strategic Evaluation

This paper reviews the value of a new lunar program, initially robotic and eventually manned, in the light of developments since the 1991 Synthes Group study of the Space Exploration Initiative. The objective is to evaluate a return to the Moon in comparison to proposed Mars programs as a focus for American space exploration with humans in the next century. The Moon is demonstrably accessible, hospitable, useful, and interesting. Lunar programs are inherently faster and less risky from a programmatic viewpoint than comparable Mars programs such as Mars Direct. The dominant reason for a resumption of manned lunar missions, focused on a single site such as Grimaldi, is to rebuild the infrastructure for missions beyond Earth orbit, the last of which was in 1972. A transitional prograrr@ corresponding to the 10 Gemini missions that bridged the gap between Mercury and Apollo, was considered absolutely essential by the Synthesis Group. Further justification for a return to the Moon is the demonstrated feasibility of a robotic lunar observatory, concentrating on optical and infrared interferometry. Many unsolved scientific questions about the Moon itself remain, and could be investigated using telerobotic lunar rovers even before the return of humans. Mars is unquestionably more interesting scientifically and far more hospitable for long-term colonization. A new lunar program would be the most effective possible preparation for the human exploration, settlement and eventually the terraforming of Mars. Lunar and Mars programs are complementary, not competitive. Both can be justified in the most fundamental terms as beginning the dispersal of the human species against uncontrollable natural disasters, cometary or asteroidal impacts in particular, to which mankind is vulnerable while confined to a single planet. Three specific programs are recommended for the 2001-2010 period: Ice Prospectors, to evaluate polar ice or hydrogen deposits; a robotic lunar observatory; and a manned lunar base and observatory.

Lowman, Paul D., Jr.↗

Electrostrictive Graft Elastomers and Applications

Efficient actuators that are lightweight, high performance and compact are needed to support telerobotic requirements for future NASA missions. In this work, we present a new class of electromechanically active polymers that can potentially be used as actuators to meet many NASA needs. The materials are graft elastomers that offer high strain under an applied electric field. Due to its higher mechanical modulus, this elastomer also has a higher strain energy density as compared to previously reported electrostrictive polyurethane elastomers. The dielectric, mechanical and electromechanical properties of this new electrostrictive elastomer have been studied as a function of temperature and frequency. Combined with structural analysis using x-ray diffraction and differential scanning calorimetry on the new elastomer, structure-property interrelationship and mechanisms of the electric field induced strain in the graft elastomer have also been investigated. This electroactive polymer (EAP) has demonstrated high actuation strain and high mechanical energy density. The combination of these properties with its tailorable molecular composition and excellent processability makes it attractive for a variety of actuation tasks. The experimental results and applications will be presented.

Su, J.↗

Modeling of Horns for Sonic/Ultrasonic Applications

JPL has a requirement for telerobotic tools for planetary sample acquisition, which require low power and have the ability to work in harsh environments. We are currently investigating the possibility of using ultrasonic horns to develop a family of ultrasonic tools for these environments. In an effort to determine control parameters a one-dimensional Mason's model for a stepped ultrasonic horn assembly was developed which includes the effects of mechanical and electrical losses in the piezoelectric material and acoustic elements. The model is separated into three regions; the piezoelectric stack including stress bolt the backing layer and the horn. The model is found to predict the impedance data of the horn assembly very accurately up to the first coupled (radial) resonance. The model also allows for the calculation of the velocity and force and power delivered to each acoustic element. FEM modeling and accelerometer data from the horn tip were used to corroborate the model. The difficulties associated with modeling the load impedance of various devices will be discussed and current directions noted.

Sherrit, Stewart↗

Automatic Inspection of Aircraft Using Open-Architecture Robotic Platforms

Aging aircraft structures and composite materials are requiring rapid inspection of large areas. Removal from the aircraft for NDE at an inspection facility is not economical as compared to field inspection. Detection and characterization of defects are labor intensive, time consuming and when the process is manual the results are subjected to human error. These limitations of NDE created a need for portable, user friendly inspection systems that can rapidly scan large areas of complex structures and locate all the detrimental material conditions. Addressing this need has been an evolutionary process that followed the technology trend, and unique devices were developed to allow rapid field inspection. This development involves multi-disciplinary approaches to integrate NDE, telerobotics, neural networks, advanced materials science, imbedded computing and automated control. These efforts have led to the development of various portable inspection systems and the current trend is towards fully automatic systems that will operate autonomously.

Bar-Cohen, Yoseph↗

NDE and Advanced Actuators for Space Applications at JPL

Nondestructive Evaluation and Advanced Actuators (NDEAA) are presented. The focus areas are on mechanisms and devices that are driven by acoustic or elastic waves. The topics include: 1) Nondestructive Evaluation; 2) Advanced Actuators; 3) Ultrasonic Medical Diagnostics and Treatment; and 4) Telerobotics.

Bar-Cohen, Yoseph↗

ISS Operations for the Special Purpose Dexterous Manipulator (SPDM) Experiences from the Robotic Systems Evaluation Laboratory (RSEL)

The International Space Station (ISS) will present a new era of telerobotic operations on-orbit. Operating the Special Purpose Dexterous Manipulator (SPDM) in its tasks of maintaining the multitude of Space Station Orbital Replaceable Units (ORUs) creates numerous operational considerations not seen in the existing Shuttle Remote Manipulator System (SRMS) or the future Space Station Remote Manipulator System (SSRMS). The differences between the large arms and the dexterous arm greatly affect the interconnection of man, robot, and task. This paper presents some of the issues arising from this new breed of on-orbit robotics as garnered from over three years of ORU testing experience within the Robotic Systems Evaluation Laboratory (RSEL) at NASA Johnson Space Center. The effects of new robotic features on operations, the issues surrounding targets and visual cues, the differences in operating with Force Moment Accommodation (FMA), the effects of changes in task complexity and scale, the lack of supporting flight information, and the changes in procedures required by the dexterous task will be discussed.

Spinler, Anthony B.↗

Control of Free-Flying Space Robot Manipulator Systems

This is the final report on the Stanford University portion of a major NASA program in telerobotics called the TRIWG Program, led strongly from NASA Headquarters by David Lavery This portion of the TRIWG research was carried out in Stanford's Aerospace Robotics Laboratory (ARL) to (1) contribute in unique and valuable ways to new fundamental capability for NASA in its space missions (the total contribution came from some 100 PhD-student years of research), and (2) to provide a steady stream of very capable PhD graduates to the American space enterprise.

Cannon, Robert H., Jr.↗

Presence of Mind... A Reaction to Sheridan's "Musing on Telepresence"

What are the benefits and significance of developing a scientifically useful measure of the human sense of presence in an environment? Such a scale could be conceived to measure the extent to which users of telerobotics interfaces feel or behave as if they were present at the site of a remotely controlled robot. The essay examines some issues raised in order to identify characteristics, a scale of 'presence' ought to have to be useful as an explanatory scientific concept. It also addresses the utility of worrying about developing such a scale at all. To be useful in the same manner as a traditional scientific concept such as mass, for example, it is argued that such scales not only need to be precisely defined and co-vary with determinative factors but also need to establish equivalence classes of its independent constituents. This simplifying property is important for either subjective or objective scales of presence and arises if the constituents of presence are truly independent.

Ellis, Stephen R.↗

Perceptual Fidelity Versus Engineering Compromises in Virtual Acoustic Displays

Immersive, three-dimensional displays are increasingly becoming a goal of advanced human-machine interfaces. While the technology for achieving truly useful multisensory environments is still being developed, techniques for generating three-dimensional sound are now both sophisticated and practical enough to be applied to acoustic displays. The ultimate goal of virtual acoustics is to simulate the complex acoustic field experienced by a listener freely moving around within an environment. Of course, such complexity, freedom of movement and interactivity is not always possible in a 'true' virtual environment, much less in lower-fidelity multimedia systems. However, many of the perceptual and engineering constraints (and frustrations) that researchers, engineers and listeners have experienced in virtual audio are relevant to multimedia. In fact, some of the problems that have been studied will be even more of an issue for lower fidelity systems that are attempting to address the requirements of a huge, diverse and ultimately unknown audience. Examples include individual differences in head-related transfer functions, A lack of real interactively (head-tracking) in many multimedia displays, and perceptual degradation due to low sampling rates and/or low-bit compression. This paper discusses some of the engineering constraints faced during implementation of virtual acoustic environments and the perceptual consequences of these constraints. Specific examples are given for NASA applications such as telerobotic control, aeronautical displays, and shuttle launch communications. An attempt will also be made to relate these issues to low-fidelity implementations such as the internet.

Wenzel, Elizabeth M.↗

Perceptual Fidelity vs. Engineering Compromises In Virtual Acoustic Displays

Immersive, three-dimensional displays are increasingly becoming a goal of advanced human-machine interfaces. While the technology for achieving truly useful multisensory environments is still being developed, techniques for generating three-dimensional sound are now both sophisticated and practical enough to be applied to acoustic displays. The ultimate goal of virtual acoustics is to simulate the complex acoustic field experienced by a listener freely moving around within an environment. Of course, such complexity, freedom of movement and interactively is not always possible in a "true" virtual environment, much less in lower-fidelity multimedia systems. However, many of the perceptual and engineering constraints (and frustrations) that researchers, engineers and listeners have experienced in virtual audio are relevant to multimedia. In fact, some of the problems that have been studied will be even more of an issue for lower fidelity systems that are attempting to address the requirements of a huge, diverse and ultimately unknown audience. Examples include individual differences in head-related transfer functions, a lack of real interactively (head-tracking) in many multimedia displays, and perceptual degradation due to low sampling rates and/or low-bit compression. This paper discusses some of the engineering Constraints faced during implementation of virtual acoustic environments and the perceptual consequences of these constraints. Specific examples are given for NASA applications such as telerobotic control, aeronautical displays, and shuttle launch communications. An attempt will also be made to relate these issues to low-fidelity implementations such as the internet.

Wenzel, Elizabeth M.↗