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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 163 records · Page 9

Operator versus computer control of adaptive automation

Adaptive automation refers to real-time allocation of functions between the human operator and automated subsystems. The article reports the results of a series of experiments whose aim is to examine the effects of adaptive automation on operator performance during multi-task flight simulation, and to provide an empirical basis for evaluations of different forms of adaptive logic. The combined results of these studies suggest several things. First, it appears that either excessively long, or excessively short, adaptation cycles can limit the effectiveness of adaptive automation in enhancing operator performance of both primary flight and monitoring tasks. Second, occasional brief reversions to manual control can counter some of the monitoring inefficiency typically associated with long cycle automation, and further, that benefits of such reversions can be sustained for some time after return to automated control. Third, no evidence was found that the benefits of such reversions depend on the adaptive logic by which long-cycle adaptive switches are triggered.

Hilburn, Brian↗

A computer controlled power tool for the servicing of the Hubble Space Telescope

The Hubble Space Telescope (HST) Pistol Grip Tool (PGT) is a self-contained, microprocessor controlled, battery-powered, 3/8-inch-drive hand-held tool. The PGT is also a non-powered ratchet wrench. This tool will be used by astronauts during Extravehicular Activity (EVA) to apply torque to the HST and HST Servicing Support Equipment mechanical interfaces and fasteners. Numerous torque, speed, and turn or angle limits are programmed into the PGT for use during various missions. Batteries are replaceable during ground operations, Intravehicular Activities, and EVA's.

Richards, Paul W.↗

Computational Control of Flexible Aerospace Systems

The main objective of this project is to establish a distributed parameter modeling technique for structural analysis, parameter estimation, vibration suppression and control synthesis of large flexible aerospace structures. This report concentrates on the research outputs produced in the last two years of the project. The main accomplishments can be summarized as follows. A new version of the PDEMOD Code had been completed. A theoretical investigation of the NASA MSFC two-dimensional ground-based manipulator facility by using distributed parameter modelling technique has been conducted. A new mathematical treatment for dynamic analysis and control of large flexible manipulator systems has been conceived, which may provide a embryonic form of a more sophisticated mathematical model for future modified versions of the PDEMOD Codes.

Sharpe, Lonnie, Jr.↗

Sample Delivery and Computer Control Systems for Detecting Leaks in the Main Engines of the Space Shuttle

The main engines of the Space Shuttle use hydrogen and oxygen as the fuel and oxidant. The explosive and fire hazards associated with these two components pose a serious danger to personnel and equipment. Therefore prior to use the main engines undergo extensive leak tests. Instead of using hazardous gases there tests utilize helium as the tracer element. This results in a need to monitor helium in the ppm level continuously for hours. The major challenge in developing such a low level gas monitor is the sample delivery system. This paper discuss a system developed to meet the requirements while also being mobile. Also shown is the calibration technique, stability, and accuracy results for the system.

Griffin, Timothy P.↗

Thermal Design and Flight Experience of the Mars Exploration Rover Spacecraft Computer-Controlled, Propulsion Line Heaters

The viewgraph presentation examines propulsion line heater design and problems in the Mars Rover. Topics include a Mars Exploration Rover (MER) project description and MER spacecraft configuration, mission overview, MER cruise stage hardware, thermal design drivers in the propulsion lines, propulsion line control set points prior to launch, MER A and B flight trajectories, MER A early and mid cruise flight experience, MER A and B mid cruise flight experience, MER B late cruise flight experience, and lessons learned

propulsion lines↗

Independent backup mode transfer and mechanism for digital control computers

An interrupt is provided to a signal processor having a non-maskable interrupt input, in response to the detection of a request for transfer to backup software. The signal processor provides a transfer signal to a transfer mechanism only after completion of the present machine cycle. Transfer to the backup software is initiated by the transfer mechanism only upon reception of the transfer signal.

Tulpule, Bhalchandra R.↗

Design Considerations of Polishing Lap for Computer-Controlled Cylindrical Polishing Process

This paper establishes a relationship between the polishing process parameters and the generation of mid spatial-frequency error. The consideration of the polishing lap design to optimize the process in order to keep residual errors to a minimum and optimization of the process (speeds, stroke, etc.) and to keep the residual mid spatial-frequency error to a minimum, is also presented.

Khan, Gufran S.↗

Computer Controlled Solid State Lighting Assembly to Emulate Diurnal Cycle and Improve Circadian Rhythm Control

A light system can simultaneously emulate more than one different diurnal cycle to individually improve circadian rhythm control for more than one observer by having each light fixture autonomously self-controlled. Each light fixture is mountable in respective locations to individually treat respective observers. Each light fixture includes one or more light elements mounted to a housing and are controllable to emit a selected light intensity at a selected light temperature. A micro controller is contained in the housing and includes memory containing instructions for one or more automatic diurnal cycle protocols. The micro controller is in communication with the memory and the one or more light elements to execute the instructions to configure the light fixture to vary the light intensity and the light temperature of the emitted light.

Holbert, Eirik↗

General-Purpose Serial Interface For Remote Control

Computer controls remote television camera. General-purpose controller developed to serve as interface between host computer and pan/tilt/zoom/focus functions on series of automated video cameras. Interface port based on 8251 programmable communications-interface circuit configured for tristated outputs, and connects controller system to any host computer with RS-232 input/output (I/O) port. Accepts byte-coded data from host, compares them with prestored codes in read-only memory (ROM), and closes or opens appropriate switches. Six output ports control opening and closing of as many as 48 switches. Operator controls remote television camera by speaking commands, in system including general-purpose controller.

Busquets, Anthony M.↗

Determination of the Critical Parameters for Remote Microscope Control

As part of a program to determine the capabilities of Telescience as applied to Microgravity Materials Science the need for a remotely controlled microscope was recognized. For this purpose we equipped a microscope with an X-Y-Z positioning device and motors on the zoom and focus controls. Computer control of these devices allowed remote operation. A standard TV camera was mounted to the computer controlled video board which could compress the image in resolution and grey scale. The operator control console was programmed to display three still video pictures as well as provide command access. A standard data transfer network was used to transmit the video data files and the command interaction was via a high speed phone modem. This system, with the microscope in the Microgravity Materials Science Laboratory (MMSL) at LeRC and the control at RPI, was used to determine the accuracy of setting, time required to achieve setting and the operator ease factor. It was found that the focus setting could be established well within the resolution limit of the TV system and that each motion took about 50 seconds and approximately 12 minutes was required to reach ?best? focus. These times could be reduced significantly with operator experience. The operators were provided with ancillary equipment which provided assistance in making the necessary decisions and they reported satisfaction with the control.

Hahn, R. C.↗

Adapting Inspection Data for Computer Numerical Control

Machining time for repetitive tasks reduced. Program converts measurements of stub post locations by coordinate-measuring machine into form used by numerical-control computer. Work time thus reduced by 10 to 15 minutes for each post. Since there are 600 such posts on each injector, time saved per injector is 100 to 150 hours. With modifications this approach applicable to machining of many precise holes on large machine frames and similar objects.

Hutchison, E. E.↗

Automatic Range Changer For SWR Meter

Commercial unit modified for antenna-pattern measurements. Addition of automatic range-changing circuit converts Hewlett-Packard 415E standing-wave-ratio (SWR) meter into radio-frequency detector suitable for computer-controlled measurements of radiation patterns of antennas. Modification gives SWR meter effective dynamic range of at least 40 dB. Includes two digital lines communicating one of four range settings to controlling computer and one digital line to inhibit transfer of data when range being changed. Ideal instrument for use in applications involving computer-controlled monitoring of power when large changes in signal level expected.

Dengler, Robert J.↗

Fault analysis of multichannel spacecraft power systems

The NASA Marshall Space Flight Center proposes to implement computer-controlled fault injection into an electrical power system breadboard to study the reactions of the various control elements of this breadboard. Elements under study include the remote power controllers, the algorithms in the control computers, and the artificially intelligent control programs resident in this breadboard. To this end, a study of electrical power system faults is being performed to yield a list of the most common power system faults. The results of this study will be applied to a multichannel high-voltage DC spacecraft power system called the large autonomous spacecraft electrical power system (LASEPS) breadboard. The results of the power system fault study and the planned implementation of these faults into the LASEPS breadboard are described.

Dugal-Whitehead, Norma R.↗

Automated maintenance for complex hybrid systems

Digital computer, Control Computer Subsystem (CCS), possess high degree of fault tolerance. CCS embodies concepts of self-test and repair. It is capable of monitoring its own performance and of identifying and replacing with standby spare any of its units that fail.

Gilley, G. C.↗