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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Dynamic task distribution for multiple cooperating robot manipulators

The issue of distributing the task among multiple robot arms while considering the manipulator dynamics is considered. The forces and moments required to move an object are distributed in such a way that extra degrees of freedom within the system may be used to satisfy or optimize criteria related to the manipulator dynamics. A method to perform such subtasks is introduced, and examples of possible criteria noted. It is expected that such techniques will produce trajectories which will be more desirable for the individual arms dynamically, since the dynamics are considered in the task distribution.

Walker, Ian D.↗
NASA NTRS1989

The effects of window shape and reticle presence on performance in a vertical alignment task

This study was conducted to evaluate the effect of selected interior work-station orientational cuing upon the ability to align a target image with local vertical in the frontal plane. Angular error from gravitational vertical in an alignment task was measured for 20 observers viewing through two window shapes (square, round), two initial orientations of a computer-generated space shuttle image, and the presence or absence of a stabilized optical alignment reticle. In terms of overall accuracy, it was found that observer error was significantly smaller for the square window and reticle-present conditions than for the round window and reticle-absent conditions. Response bias data reflected an overall tendency to undershoot and greater variability of response in the round window/no reticle condition. These results suggest that environmental cuing information, such as that provided by square window frames and alignment reticles, may aid in subjective orientation and increase accuracy of response in a Space Station proximity operations alignment task.

Rosenberg, Erika L.↗
NASA NTRS1989

Planning time-optimal robotic manipulator motions and work places for point-to-point tasks

A method is presented which combines simple time-optimal motions in an optimal manner to yield the minimum-time motions for an important class of complex manipulator tasks composed of point-to-point moves such as assembly, electronic component insertion, and spot welding. This method can also be used to design manipulator actions and work places so that tasks can be completed in minimum time. The method has been implemented in a computer-aided design software system. Several examples are presented. Experimental results show the method's validity and utility.

Dubowsky, S.↗
NASA NTRS1989

Automation of learning-set testing - The video-task paradigm

Researchers interested in studying discrimination learning in primates have typically utilized variations in the Wisconsin General Test Apparatus (WGTA). In the present experiment, a new testing apparatus for the study of primate learning is proposed. In the video-task paradigm, rhesus monkeys (Macaca mulatta) respond to computer-generated stimuli by manipulating a joystick. Using this apparatus, discrimination learning-set data for 2 monkeys were obtained. Performance on Trial 2 exceeded 80 percent within 200 discrimination learning problems. These data illustrate the utility of the video-task paradigm in comparative research. Additionally, the efficient learning and rich data that were characteristic of this study suggest several advantages of the present testing paradigm over traditional WGTA testing.

Washburn, David A.↗
NASA NTRS1989

Report of the NASA lunar energy enterprise case study task force

The Lunar Energy Enterprise Cast Study Task Force was formed to determine the economic viability and commercial business potential of mining and extracting He-3 from the lunar soil for use in earth-based fusion reactors. In addition, the Solar Power Satellite (SPS) and the Lunar Power Station (LPS) were also evaluated because they involve the use of lunar materials and could provide energy for lunar-based activities. The Task Force considered: (1) the legal and liability aspects of the space energy projects; (2) the long-range terrestrial energy needs and options; (3) the technical maturity of the three space energy projects; and (4) their commercial potential. The use of electricity is expected to increase, but emerging environmental concerns and resource availability suggest changes for the national energy policy. All three options have the potential to provide a nearly inexhaustible, clean source of electricity for the U.S. and worldwide, without major adverse impacts on the Earth's environment. Assumption by industry of the total responsibility for these energy projects is not yet possible. Pursuit of these energy concepts requires the combined efforts of government and industry. The report identifies key steps necessary for the development of these concepts and an evolving industrial role.

Source record↗
NASA NTRS1989

The flight telerobotic servicer Tinman concept: System design drivers and task analysis

A study was conducted to develop a preliminary definition of the Flight Telerobotic Servicer (FTS) that could be used to understand the operational concepts and scenarios for the FTS. Called the Tinman, this design concept was also used to begin the process of establishing resources and interfaces for the FTS on Space Station Freedom, the National Space Transportation System shuttle orbiter, and the Orbital Maneuvering vehicle. Starting with an analysis of the requirements and task capabilities as stated in the Phase B study requirements document, the study identified eight major design drivers for the FTS. Each of these design drivers and their impacts on the Tinman design concept are described. Next, the planning that is currently underway for providing resources for the FTS on Space Station Freedom is discussed, including up to 2000 W of peak power, up to four color video channels, and command and data rates up to 500 kbps between the telerobot and the control station. Finally, an example is presented to show how the Tinman design concept was used to analyze task scenarios and explore the operational capabilities of the FTS. A structured methodology using a standard terminology consistent with the NASA/National Bureau of Standards Standard Reference Model for Telerobot Control System Architecture (NASREM) was developed for this analysis.

Andary, J. F.↗
NASA NTRS1989

Uniform task level definitions for robotic system performance comparisons

A series of ten task levels of increasing difficulty was compiled for use in comparative performance evaluations of available and future robotics technology. Each level has a breakdown of ten additional levels of difficulty to provide a layering of 100 levels. It is assumed that each level of task performance must be achieved by the system before it can be appropriately considered for the next level.

Price, Charles↗
NASA NTRS1989

Benchmarking Ada tasking on tightly coupled multiprocessor architectures

The development of benchmarks and performance measures for parallel Ada tasking is reported with emphasis on the macroscopic behavior of the benchmark across a set of load parameters. The application chosen for the study was the NASREM model for telerobot control, relevant to many NASA missions. The results of the study demonstrate the potential of parallel Ada in accomplishing the task of developing a control system for a system such as the Flight Telerobotic Servicer using the NASREM framework.

Collard, Philippe↗
NASA NTRS1989

Ground Communication Facility (GCF) upgrade task for Deep Space Network

The GCF upgrade task for NASA's Deep Space Network (DSN) is described. The DSN is a multimission telecommunications and radiometric data facility used to support space science, exploration, and applications by communicating with spacecraft and observing other radio sources. The GCF upgrade task is a six-year project designed to increase the data rate throughout capacity from 280 kbps to 2.272 Mbps from each tracking area to JPL, and 224 kbps from JPL to each tracking area. This would be accomplished by using a selective automatic repeat request error correction scheme in all throughput data.

Hung, Chaw-Kwei↗
NASA NTRS1989

Frame of reference for electronic maps - The relevance of spatial cognition, mental rotation, and componential task analysis

Three experiments are reported that examine the difference between north-up and track-up maps for airborne navigation. The results of the first two experiments, conducted in a basic laboratory setting, identified the cost associated with mental rotation, when a north-up map is used. However, the data suggest that these costs are neither large nor consistent. The third experiment examined a range of tasks in a higher fidelity helicopter flight simulation, and associated the costs of north-up maps with a cognitive component related to orientation, and the costs of track-up maps with a cognitive component related to inconsistent landmark location. Different tasks are associated with different dependence on these components. The results are discussed in terms of their implications for map design, and for cognitive models of navigational processes.

Wickens, Christopher D.↗
NASA NTRS1989

Speech versus manual control of camera functions during a telerobotic task

Voice input for control of camera functions was investigated in this study. Objective were to (1) assess the feasibility of a voice-commanded camera control system, and (2) identify factors that differ between voice and manual control of camera functions. Subjects participated in a remote manipulation task that required extensive camera-aided viewing. Each subject was exposed to two conditions, voice and manual input, with a counterbalanced administration order. Voice input was found to be significantly slower than manual input for this task. However, in terms of remote manipulator performance errors and subject preference, there was no difference between modalities. Voice control of continuous camera functions is not recommended. It is believed that the use of voice input for discrete functions, such as multiplexing or camera switching, could aid performance. Hybrid mixes of voice and manual input may provide the best use of both modalities. This report contributes to a better understanding of the issues that affect the design of an efficient human/telerobot interface.

Bierschwale, John M.↗
NASA NTRS1990

Analyzing the flared landing task with pitch-rate flight control systems

A closed-loop handling qualities methodology is applied to an analysis of the flared landing task with pitch-rate flight control systems. A model of pilot behavior throughout approach and flare is developed which postulates the manner in which the pilot may move from pitch attitude to flight path angle control. Twenty-five configurations flight tested on the NC-131H Total In-flight Simulator aircraft are analyzed using a structural pilot model ad a handling qualities methodology previously reported in the literature. Closed-loop simulation of the simplified landing task is undertaken using the structural model. The pilot ratings from flight test extended the data base supporting the utility of a model-based handling qualities metric. A handling qualities sensitivity function is introduced which may have potential as a design tool.

Hess, Ronald A.↗
NASA NTRS1990

Using Ada tasks to simulate operating equipment

A method of simulating equipment using Ada tasks is discussed. Individual units of equipment are coded as concurrently running tasks that monitor and respond to input signals. This technique has been used in a simulation of the space-to-ground Communications and Tracking subsystem of Space Station Freedom.

Deacetis, Louis A.↗
NASA NTRS1990

QUEST/Ada (Query Utility Environment for Software Testing of Ada): The development of a prgram analysis environment for Ada, task 1, phase 2

The results of research and development efforts are described for Task one, Phase two of a general project entitled The Development of a Program Analysis Environment for Ada. The scope of this task includes the design and development of a prototype system for testing Ada software modules at the unit level. The system is called Query Utility Environment for Software Testing of Ada (QUEST/Ada). The prototype for condition coverage provides a platform that implements expert system interaction with program testing. The expert system can modify data in the instrument source code in order to achieve coverage goals. Given this initial prototype, it is possible to evaluate the rule base in order to develop improved rules for test case generation. The goals of Phase two are the following: (1) to continue to develop and improve the current user interface to support the other goals of this research effort (i.e., those related to improved testing efficiency and increased code reliable); (2) to develop and empirically evaluate a succession of alternative rule bases for the test case generator such that the expert system achieves coverage in a more efficient manner; and (3) to extend the concepts of the current test environment to address the issues of Ada concurrency.

Brown, David B.↗
NASA NTRS1990

Evaluation of the Trajectory Operations Applications Software Task (TOAST)

The Trajectory Operations Applications Software Task (TOAST) is a software development project under the auspices of the Mission Operations Directorate. Its purpose is to provide trajectory operation pre-mission and real-time support for the Space Shuttle program. As an Application Manager, TOAST provides an isolation layer between the underlying Unix operating system and the series of user programs. It provides two main services: a common interface to operating system functions with semantics appropriate for C or FORTRAN, and a structured input and output package that can be utilized by user application programs. In order to evaluate TOAST as an Application Manager, the task was to assess current and planned capabilities, compare capabilities to functions available in commercially-available off the shelf (COTS) and Flight Analysis Design System (FADS) users for TOAST implementation. As a result of the investigation, it was found that the current version of TOAST is well implemented and meets the needs of the real-time users. The plans for migrating TOAST to the X Window System are essentially sound; the Executive will port with minor changes, while Menu Handler will require a total rewrite. A series of recommendations for future TOAST directions are included.

Perkins, Sharon↗
NASA NTRS1991

Space Station Freedom coupling tasks: An evaluation of their space operational compatibility

The development of the Space Station Freedom tasks that are compatible with both telerobotic as well as extravehicular activity is a necessary redundancy in order to insure successful day to day operation. One task to be routinely performed aboard Freedom will be the changeout of various quick disconnect fluid connectors. In an attempt to resolve these potentially contradictory issues of compatibility, mock-ups of couplings suitable to both extravehicular as well as telerobotic activity were designed and built. An evaluation performed at the Remote Operator Interaction Laboratory at NASA's Johnson Space Center is discussed, which assessed the prototype couplings as well as three standard coupling designs. Data collected during manual and telerobotic manipulation of the couplings indicated that the custom coupling was in fact shown to be faster to operate and generally preferred over the standard coupling designs.

Sampaio, Carlos E.↗
NASA NTRS1991

NSI security task: Overview

An overview is presented of the NASA Science Internet (NSI) security task. The task includes the following: policies and security documentation; risk analysis and management; computer emergency response team; incident handling; toolkit development; user consulting; and working groups, conferences, and committees.

Tencati, Ron↗
NASA NTRS1990

Generalized compliant motion task description and execution within a complete telerobotic system

A motion primitive for use in compliant motion robot task execution is described. The primitive has a rich input parameter set to provide for execution of a variety of specific tasks such as door opening, crank turning, bolt seating and turning, pushing, sliding, pin insertion/removal, and leveling, as well as termination conditions which specify conditions for ending the motion, such as allowable position and force error bounds. A split rate force control technique is used for force control. Force and torque data from a six-axis force sensor are read, and gravity compensation using load mass properties is done to determine contact forces.

Backes, Paul G.↗