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At least 307 records · Page 17

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NASA NTRS1994

A smart telerobotic system driven by monocular vision

A robotic system that accepts autonomously generated motion and control commands is described. The system provides images from the monocular vision of a camera mounted on a robot's end effector, eliminating the need for traditional guidance targets that must be predetermined and specifically identified. The telerobotic vision system presents different views of the targeted object relative to the camera, based on a single camera image and knowledge of the target's solid geometry.

Defigueiredo, R. J. P.↗

NASA NTRS1994

Smart vision chips: An overview

This viewgraph presentation presents four working analog VLSI vision chips: (1) time-derivative retina, (2) zero-crossing chip, (3) resistive fuse, and (4) figure-ground chip; work in progress on computing motion and neuromorphic systems; and conceptual and practical lessons learned.

Koch, Christof↗

NASA NTRS1996

Coupled mixed-field laminate theory and finite element for smart piezoelectric composite shell structures

Mechanics for the analysis of laminated composite shells with piezoelectric actuators and sensors are presented. A new mixed-field laminate theory for piezoelectric shells is formulated in curvilinear coordinates which combines single-layer assumptions for the displacements and a layerwise representation for the electric potential. The resultant coupled governing equations for curvilinear piezoelectric laminates are described. Structural mechanics are subsequently developed and an 8-node finite-element is formulated for the static and dynamic analysis of adaptive composite structures of general laminations containing piezoelectric layers. Evaluations of the method and comparisons with reported results are presented for laminated piezoelectric-composite plates, a closed cylindrical shell with a continuous piezoceramic layer and a laminated composite semi-circular cantilever shell with discrete cylindrical piezoelectric actuators and/or sensors.

Saravanos, Dimitris A.↗

NASA NTRS1996

Layerwise Finite Elements for Smart Piezoceramic Composite Plates in Thermal Environments

Analytical formulations are presented which account for the coupled mechanical, electrical, and thermal response of piezoelectric composite laminates and plate structures. A layerwise theory is formulated with the inherent capability to explicitly model the active and sensory response of piezoelectric composite plates having arbitrary laminate configurations in thermal environments. Finite element equations are derived and implemented for a bilinear 4-noded plate element. Application cases demonstrate the capability to manage thermally induced bending and twisting deformations in symmetric and antisymmetric composite plates with piezoelectric actuators, and show the corresponding electrical response of distributed piezoelectric sensors. Finally, the resultant stresses in the thermal piezoelectric composite laminates are investigated.

Saravanos, Dimitris A.↗

NASA NTRS1996

Robust, Brillouin Active Embedded Fiber-Is-The-Sensor System in Smart Composite Structures

Extensive review of our proposed sensing scheme, based mainly on the forward Guided Acoustic Wave Brillouin Scattering (GAWBS) with backward stimulated Brillouin scattering (sBs) as an auxiliary scheme for system fault tolerance has been completed during this project period. This preliminary study is conducted for a number of reasons. The most significant reasons lie in the essential capability of the system to measure temperature and pressure. These two measurands have been proposed to be sensed by sBs in our proposal. Temperature and pressure/strain are important measurands in structural monitoring, so that the effectiveness of sensing by sBs needs to be further examined. It has been pointed out initially that sBs shift will be dependent on temperature and pressure/strain simultaneously. The shift versus temperature or strain is linear. Now, the question is how can these two measurands be separated when sBs is used to sense an environment, in which both temperature and strain are changing simultaneously. Typical sBs shift plotted versus strain and varying temperature is shown in Fig. 1. As is clear, a fiber initially stressed will relax with rising temperature. This is verified by a displacement to the right with rising temperature of the sBs shift vs strain curves in the figure. A way to circumvent this ambiguity is by employing two fibers, one pre-stressed and the other is a free fiber. The latter will measure temperature and subtracting data in the latter fiber from those of the former will give us net strain readings. This is a laborious approach, since it involves the use of two identical fibers, and this is hard to accomplish, especially when many sensors are needed. Additional multiplexing of the data stream for data subtraction becomes a necessity.

Yu, Chung↗

NASA NTRS1997

Theoretical Limits of Damping Attainable by Smart Beams with Rate Feedback

Using a generally accepted model we present a comprehensive analysis (within the page limitation) of an Euler- Bernoulli beam with PZT sensor-actuator and pure rate feedback. The emphasis is on the root locus - the dependence of the attainable damping on the feedback gain. There is a critical value of the gain beyond which the damping decreases to zero. We construct the time-domain response using semigroup theory, and show that the eigenfunctions form a Riesz basis, leading to a 'modal' expansion.

Balakrishnan, A. V.↗

NASA NTRS1998

Smart Optical RAM for Fast Information Management and Analysis

Statement of Problem Instruments for high speed and high capacity in-situ data identification, classification and storage capabilities are needed by NASA for the information management and analysis of extremely large volume of data sets in future space exploration, space habitation and utilization, in addition to the various missions to planet-earth programs. Parameters such as communication delays, limited resources, and inaccessibility of human manipulation require more intelligent, compact, low power, and light weight information management and data storage techniques. New and innovative algorithms and architecture using photonics will enable us to meet these challenges. The technology has applications for other government and public agencies.

Liu, Hua-Kuang↗

NASA NTRS1999

SMART (Shop floor Modeling, Analysis and Reporting Tool Project

This document presents summarizes the design and prototype of the Shop floor Modeling, Analysis, and Reporting Tool (S.M.A.R.T.) A detailed description of it is found on the full documentation given to the NASA liaison. This documentation is also found on the A.R.I.S.E. Center web site, under a projected directory. Only authorized users can gain access to this site.

Centeno, Martha A.↗

NASA NTRSDate not supplied

To the Die Smartly: Heavy Ion Testing of PEMs on COTS Boards Through the Plastic

Seven commercial off the shelf (COTS) boards containing electronic devices (all in plastic packages, PEMS), under consideration for use in a spacecraft subsystem, were exposed to beams of very high energy ions at the National Superconducting Cyclotron Laboratory (MSU). The ion energies were high enough that an entire board could be exposed in air, and it could still penetrate through the plastic and reach the silicon die. A total of about 300 runs were made, and for each, the LET of the ion entering the silicon die had to be determined, based on the thickness of the plastic lid and the thickness of overlaying materials (e.g., aluminum degraders). Single event latchup (SEL) and functional interrupt (SEFI) were determined during each run, the SEFI by means of simple programs being continuously written to and read from the boards to monitor functionality, while each part was being exposed to the heavy ions.

Wert, J. L.↗

NASA NTRS1999

Vibration Analysis and Control of Flexible Beam by Using Smart Damping Structures

The temperature effects on frequency, loss factor and control of a flexible beam with a constrained viscoelastic layer and shape memory alloy layer (SMA) are discussed. It is shown that the temperature in the SMA (actuation) layer is very important in the determination of frequency and loss factor of such a structure. The effects of damping layer shear modulus and damping layer height as affected by the temperature are also discussed. As temperature plays such an important role, it is, therefore, imperative to evaluate temperature effects on the control of the system as well. Results with and without active control are discussed.

Chen, Q.↗

NASA NTRS1999

Fiber Optic Sensor Components and Systems for Smart Materials and Structures

The general objective of the funded research effort has been the development of discrete and distributed fiber sensors and fiber optic centered opto-electronic networks for the intelligent monitoring of phenomena in various aerospace structures related to NASA Marshall specific applications. In particular, we have proposed and have been developing technologies that we believe to be readily transferrable and which involve new fabrication techniques. The associated sensors developed can be incorporated into the matrix or on the surfaces of structures for the purpose of sensing stress, strain, temperature-both low and high, pressure field variations, phase changes, and the presence of various chemical constituents.

Lyons, R.↗

NASA NTRS2000

Autonomous Landing and Smart Anchoring for In-Situ Exploration of Small Bodies

Future NASA missions include in-situ scientific explorations of small interplanetary objects like comets and asteroids. Sample acquisition systems are envisioned to operate directly from the landers that are anchored to the surface. Landing and anchoring proves to be challenging in the absence of an attitude control system and in the presence of nearly zero-gravity environments with uncertain surface terrain and unknown mechanical properties. This paper presents recent advancements in developing a novel landing and anchoring control system for the exploration of small bodies.

Ghavimi, Ali R.↗

NASA NTRS2000

Patch Network for Power Allocation and Distribution in Smart Materials

The power allocation and distribution (PAD) circuitry is capable of allocating and distributing a single or multiple sources of power over multi-elements of a power user grid system. The purpose of this invention is to allocate and distribute power that is collected by individual patch rectennas to a region of specific power-user devices, such as actuators. The patch rectenna converts microwave power into DC power. Then this DC power is used to drive actuator devices. However, the power from patch rectennas is not sufficient to drive actuators unless all the collected power is effectively used to drive another group by allocation and distribution. The power allocation and distribution (PAD) circuitry solves the shortfall of power for devices in a large array. The PAD concept is based on the networked power control in which power collected over the whole array of rectennas is allocated to a sub domain where a group of devices is required to be activated for operation. Then the allocated power is distributed to individual element of power-devices in the sub domain according to a selected run-mode.

Golembiewski, Walter T.↗

NASA NTRS2001

Infrared Fibers for Use in Space-Based Smart Structures

Infrared optical fibers are finding a number of applications including laser surgery, remote sensing, and nuclear radiation resistant links. Utilizing these fibers in space-based structures is another application, which can be exploited. Acoustic and thermal sensing are two areas in which these fibers could be utilized. In particular, fibers could be embedded in IM7/8552 toughened epoxy and incorporated into space structures both external and internal. ZBLAN optical fibers are a candidate, which have been studied extensively over the past 20 years for terrestrial applications. For the past seven years the effects of gravity on the crystallization behavior of ZBLAN optical fiber has been studied. It has been found that ZBLAN crystallization is suppressed in microgravity. This lack of crystallization leads to a fiber with better transmission characteristics than its terrestrial counterpart.

Tucker, Dennis S.↗

NASA NTRS1998

Software Smarts

Under an SBIR (Small Business Innovative Research) contract with Johnson Space Center, Knowledge Based Systems Inc. (KBSI) developed an intelligent software environment for modeling and analyzing mission planning activities, simulating behavior, and, using a unique constraint propagation mechanism, updating plans with each change in mission planning activities. KBSI developed this technology into a commercial product, PROJECTLINK, a two-way bridge between PROSIm, KBSI's process modeling and simulation software and leading project management software like Microsoft Project and Primavera's SureTrak Project Manager.

Source record↗

NASA NTRS1993

Smart Starter

A NASA-developed technology provides an effective and economical method of starting standard three phase motors. Firing Circuits, Inc. uses the power factor controller in its Wattstop Reduced Voltage AC Motor Starters. The power factor controller matches voltage with a motor's actual need by continuously sensing shifts between voltage and circuit. Energy savings range from 8 to 65 percent. Wattstops are used on cranes, hoists, conveyors, fans, as well as in papermaking, woodworking, metalworking, and many other applications.

Source record↗

NASA NTRS1984

Big Savings from Smart Motors

Chesebrough-Pond's operates 32 plants across the nation and in those plants are more than 10,000 electric motors. In an effort to cut down on waste of electrical power used by these motors, Chesebrough organized a Corporate Advanced Technology Group to devise ways of improving productivity and cut manufacturing costs. Chesebrough used NASA's Marshall Space Flight Center's Power Factor Controller technology as a departure point for development of their own computerized motor controller that enables motors to operate at maximum efficiency regardless of the motor's applications or operating condition.

Source record↗

NASA NTRS2003

Smart Buying

When it came time to buy the next-generation data storage system for the Mission Control Center at Johnson Space Center, we asked our contractor who provides Control Center support to come up with a solution that would consolidate three current storage systems, as well as provide additional capability and functionality - all without spending vast amounts of money. Eventually, the contractor's report arrived at my office. To my great disappointment, the proposed system came along with a multi-million dollar price tag. And, even more disappointing, the system relied on the same technology we already had in place and wouldn't deliver much additional functionality. It was clear that we needed to come up with a better solution-the best we could buy. But how do you buy the best technology, when you don't even know what technology is out there?

Gonzalez, Steven A.↗