Researchers at the U.S. Bureau of Mines have developed adaptive process control systems in which genetic algorithms (GA's) are used to augment fuzzy logic controllers (FLC's). GA's are search algorithms that rapidly locate near-optimum solutions to a wide spectrum of problems by modeling the search procedures of natural genetics. FLC's are rule based systems that efficiently manipulate a problem environment by modeling the 'rule-of-thumb' strategy used in human decision-making. Together, GA's...

Topics: NASA Technical Reports Server (NTRS), ADAPTIVE CONTROL, ALGORITHMS, CONTROLLERS, DECISION MAKING,...

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194

Sep 20, 2010
09/10

by
Goualard, Jacques; Paugam, D.; Borthomieu, Y

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The results of tests to assess capacity loss in nickel hydrogen cells are presented in outline form. The effects of long storage (greater than 1 month), high hydrogen pressure storage, high cobalt content, and recovery actions are addressed.

Topics: CONTROL SYSTEMS DESIGN, CONTROLLERS, FUZZY SYSTEMS, GENETIC ALGORITHMS, EQUATIONS OF MOTION,...

The Parallel Diagonal Dominant (PDD) algorithm is a highly efficient, ideally scalable tridiagonal solver. In this paper, a detailed study of the PDD algorithm is given. First the PDD algorithm is introduced. Then the algorithm is extended to solve periodic tridiagonal systems. A variant, the reduced PDD algorithm, is also proposed. Accuracy analysis is provided for a class of tridiagonal systems, the symmetric, and anti-symmetric Toeplitz tridiagonal systems. Implementation results show that...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, MASSIVELY PARALLEL PROCESSORS, PARALLEL...

The Parallel Diagonal Dominant (PDD) algorithm is a highly efficient, ideally scalable tridiagonal solver. In this paper, a detailed study of the PDD algorithm is given. First the PDD algorithm is introduced. Then the algorithm is extended to solve periodic tridiagonal systems. A variant, the reduced PDD algorithm, is-also proposed. Accuracy analysis is provided for a class of tridiagonal systems, the symmetric and anti-symmetric Toeplitz tridiagonal systems. Implementation results show that...

Topics: DTIC Archive, Sun, Xian-He, INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON...

The capabilities of flight control systems can be enhanced by designing them to emulate functions of natural intelligence. Intelligent control functions fall in three categories. Declarative actions involve decision-making, providing models for system monitoring, goal planning, and system/scenario identification. Procedural actions concern skilled behavior and have parallels in guidance, navigation, and adaptation. Reflexive actions are spontaneous, inner-loop responses for control and...

Topics: NASA Technical Reports Server (NTRS), DECISION MAKING, FLIGHT CONTROL, INTELLIGENCE, NAVIGATION,...

267
267

Sep 20, 2010
09/10

by
Whitmore, Stephen A.; Moes, Timothy R.; Czerniejewski, Mark W.; Nichols, Douglas A

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The feasibility of locating a flush airdata sensing (FADS) system on a wing leading edge where the operation of the avionics or fire control radar system will not be hindered is investigated. The leading-edge FADS system (LE-FADS) was installed on an unswept symmetrical airfoil and a series of low-speed wind-tunnel tests were conducted to evaluate the performance of the system. As a result of the tests it is concluded that the aerodynamic models formulated for use on aircraft nosetips are...

Topics: COMPUTATIONAL FLUID DYNAMICS, SUPERSONIC FLOW, TURBULENCE MODELS, ALGORITHMS, EDUCATION, HYPERSONIC...

An algorithm developed at Oak Ridge National Laboratory accurately and quickly predicts thermodynamic properties of concentrated aqueous salt solutions. This algorithm is much simpler and much faster than other modeling schemes and is unique because it can predict solution behavior at very high concentrations and under varying conditions. Typical industrial applications of this algorithm would be in manufacture of inorganic chemicals by crystallization, thermal storage, refrigeration and...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, AQUEOUS SOLUTIONS, PREDICTIONS, PROCESSING,...

This paper categorizes the qualitative behavior of the Command and Control Segment (CCS) differential correction algorithm as applied to attitude estimation using simultaneous spin axis sun angle and Earth cord length measurements. The categories of interest are the domains of convergence, divergence, and their boundaries. Three series of plots are discussed that show the dependence of the estimation algorithm on the vehicle radius, the sun/Earth angle, and the spacecraft attitude. Common...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, ATTITUDE (INCLINATION), ATTITUDE CONTROL, COMMAND...

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237

Sep 20, 2010
09/10

by
Miglin, M. F.; Campion, R. E.; Lemos, P. J.; Tran, T

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The Low-power Atmospheric Compensation Experiment (LACE) satellite, launched in February 1990 by the Naval Research Laboratory, uses a magnetic damper on a gravity gradient boom and a momentum wheel with its axis perpendicular to the plane of the orbit to stabilize and maintain its attitude. Satellite attitude is determined using three types of sensors: a conical Earth scanner, a set of sun sensors, and a magnetometer. The Ultraviolet Plume Instrument (UVPI), on board LACE, consists of two...

Topics: ALGORITHMS, ANOMALIES, COMPUTERIZED SIMULATION, CHARGE COUPLED DEVICES, ENVIRONMENTAL TESTS, ERROR...

We show how LTL model checking can be reduced to CTL model checking with fairness constraints. Using this reduction, we also describe how to construct a symbolic LTL model checker that appears to be quite efficient in practice. In particular, we show how the SMV model checking system developed by McMillan 16 can be extended to permit LTL specifications. The results that we have obtained are quite surprising. For the examples we considered, the LTL model checker required at most twice as much...

Topics: DTIC Archive, Clarke, E, CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF COMPUTER SCIENCE, *ALGORITHMS,...

These are the lecture notes for CS 15-840B, a hands-on class in programming parallel algorithms. The class was taught in the fall of 1992 by Guy Blelloch, using the programming, language NESL. It stressed the clean and concise expression of a variety of parallel algorithms. About 35 graduate students attended the class', of whom 28 took it for credit. These notes were written by students in the class, and were then reviewed and organized by Guy Blelloch and Jonathan Hardwick. The sample NESL...

Topics: DTIC Archive, Blelloch, Guy E, CARNEGIE-MELLON UNIV PITTSBURGH PA SCHOOL OF COMPUTER SCIENCE,...

A method for generating finite-dimensional approximations to the solutions of optimal control problems is introduced. By employing a description of the dynamical system in terms of its attainable sets in favor of using differential equations, the controls are completely eliminated from the system model. Besides reducing the dimensionality of the discretized problem compared to state-of-the-art collocation methods, this approach also alleviates the search for initial guesses from where standard...

Topics: NASA Technical Reports Server (NTRS), COLLOCATION, DIFFERENTIAL EQUATIONS, OPTIMAL CONTROL, PROBLEM...

It is the objective of this paper to present a model reduction technique developed for the integrated controls-structures design of flexible structures. Integrated controls-structures design problems are typically posed as nonlinear mathematical programming problems, where the design variables consist of both structural and control parameters. In the solution process, both structural and control design variables are constantly changing; therefore, the dynamic characteristics of the structure...

Topics: NASA Technical Reports Server (NTRS), ACTUATORS, ALGORITHMS, CONTROL SYSTEMS DESIGN, DESIGN...

We have designed and implemented a query processor, called APPROXIMATE, that makes approximate answers available if part of the database is unavailable or if there is not enough time to produce an exact answer. The accuracy of the approximate answers produced improves monotonically with the amount of data retrieved to produce the result. The exact answer is produced if all of the needed data are available and query processing is allowed to continue until completion. The monotone query...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, DATA BASES, QUERY LANGUAGES, SEMANTICS, BOOLEAN...

The attitude matrix minimizing Wahba's loss function is computed directly by a method that is competitive with the fastest known algorithm for finding this optimal estimate. The method also provides an estimate of the attitude error covariance matrix. Analysis of the special case of two vector observations identifies those cases for which the TRIAD or algebraic method minimizes Wahba's loss function.

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, ATTITUDE (INCLINATION), ATTITUDE INDICATORS,...

We study a routing problem that arises on SIMD parallel architectures whose communication network forms a toroidal mesh. We assume there exists a set of k message descriptors (xi, yi), where (xi, yi) indicates that the ith message's recipient is offset from its sender by xi hops in one mesh dimension, and yi hops in the other. Every processor has k messages to send, and all processors use the same set of message routing descriptors. The SIMD constraint implies that at any routing step, every...

Topics: NASA Technical Reports Server (NTRS), ARCHITECTURE (COMPUTERS), COMMUNICATION NETWORKS, COMPUTER...

Internetworking protocols such as IP currently do not allow 'mobile hosts' to interoperate easily or conveniently with other hosts on the network. A host's IP address encodes the network number to which the host is connected, which prevents IP datagrams from reaching the host when it moves to a new location and connects to the Internet within a different network. This paper presents a new protocol for allowing mobile hosts to transparently interoperate in the Internet using IP. The protocol is...

Topics: DTIC Archive, Johnson, David B, CARNEGIE-MELLON UNIV PITTSBURGH PA SCHOOL OF COMPUTER SCIENCE,...

This report consists of a collection of journal articles and conference proceedings covering a decade of research into synthetic aperture radar (SAR) remote sensing of the Arctic regions. Four main areas are covered: (1) Data collections and SAR imaging generation, (2) Geophysical parameter estimation, (3) Sensor intercomparison; and (4) Algorithm development.

Topics: DTIC Archive, Shuchman, R A, ENVIRONMENTAL RESEARCH INST OF MICHIGAN ANN ARBOR, *SYNTHETIC APERTURE...

The system-level software onboard a spacecraft is responsible for recovery from communication, power, thermal, and computer-health anomalies that may occur. The recovery must occur without disrupting any critical scientific or engineering activity that is executing at the time of the error. Thus, the error-recovery software may have to execute concurrently with the ongoing acquisition of scientific data or with spacecraft maneuvers. This work provides a technique by which the rules that...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, ANOMALIES, CONSTRAINTS, ERROR ANALYSIS, RECOVERY,...

The User-Interface Technology Branch at NCCOSC RDT&E Division has been conducting a series of studies to address the suitability of commercial off-the-shelf (COTS) graphic user-interface (GUI) methods for efficiency and performance in critical naval combat systems. This paper presents an advanced selection algorithm and method developed to increase user performance when making selections on tactical displays. The method has also been applied with considerable success to a variety of cursor...

Topics: NASA Technical Reports Server (NTRS), COMPUTER GRAPHICS, COMPUTER TECHNIQUES, DISPLAY DEVICES,...

One of the core constructs of High Performance Fortran (HPF) is the array-slice assignment statement. combined with the rich choice of data distribution options available to the programmer. On a private memory multicomputer, the HPF compiler writer faces the difficult task of automatically generating the necessary communication for assignment statements involving arrays with arbitrary block-cyclic data distributions. In this paper we present a framework for representing array slices and...

Topics: DTIC Archive, Stichnoth, James M, CARNEGIE-MELLON UNIV PITTSBURGH PA SCHOOL OF COMPUTER SCIENCE,...

This report investigates the classification of power system states using an artificial neural network model, Kohonen's self-organizing feature map. The ultimate goal of this classification is to assess power system static security in real-time. Kohonen's self-organizing feature map is an unsupervised neural network which maps N-dimensional input vectors to an array of M neurons. After learning, the synaptic weight vectors exhibit a topological organization which represents the relationship...

Topics: NASA Technical Reports Server (NTRS), CLASSIFICATIONS, ELECTRIC POWER SUPPLIES, NEURAL NETS, POWER...

The popular QR algorithm for solving all eigenvalues of an unsymmetric matrix is reviewed. Among the basic components in the QR algorithm, it was concluded from this study, that the reduction of an unsymmetric matrix to a Hessenberg form (before applying the QR algorithm itself) can be done effectively by exploiting the vector speed and multiple processors offered by modern high-performance computers. Numerical examples of several test cases have indicated that the proposed parallel-vector...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, EIGENVALUES, MATRICES (MATHEMATICS), PARALLEL...

This paper introduces the IND Tree Package to prospective users. IND does supervised learning using classification trees. This learning task is a basic tool used in the development of diagnosis, monitoring and expert systems. The IND Tree Package was developed as part of a NASA project to semi-automate the development of data analysis and modelling algorithms using artificial intelligence techniques. The IND Tree Package integrates features from CART and C4 with newer Bayesian and minimum...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, CLASSIFICATIONS, EXPERT SYSTEMS, MACHINE...

A series of experiments was conducted to evaluate the real-time performance of a proposed agent architecture. The architecture is a blackboard architecture whose key features include: distribution of perception, action, and cognition among parallel processes; limited-capacity I/O buffers with best-first retrieval and worst-first overflow; dynamic control planning; dynamic focus of attention; and a satisficing algorithm for the execution cycle. The experiments focus on the architecture's...

Topics: DTIC Archive, Hayes-Roth, Barbara, STANFORD UNIV CA KNOWLEDGE SYSTEMS LAB, *ARTIFICIAL...

The Space Station Freedom will require the supply of items in a regular fashion. A schedule for the delivery of these items is not easy to design due to the large span of time involved and the possibility of cancellations and changes in shuttle flights. This paper presents the basic concepts of a genetic algorithm model, and also presents the results of an effort to apply genetic algorithms to the design of propellant resupply schedules. As part of this effort, a simple simulator and an...

Topics: NASA Technical Reports Server (NTRS), GENETIC ALGORITHMS, GENETICS, SCHEDULING, SPACE STATION...

Genetic algorithms (GA's), as introduced by Holland (1975), are one form of directed random search. The form of direction is based on Darwin's 'survival of the fittest' theories. GA's are radically different from the more traditional design optimization techniques. GA's work with a coding of the design variables, as opposed to working with the design variables directly. The search is conducted from a population of designs (i.e., from a large number of points in the design space), unlike the...

Topics: NASA Technical Reports Server (NTRS), ACTUATORS, CONTROL SYSTEMS DESIGN, DESIGN ANALYSIS, GENETIC...

In recent years the employment of active control techniques for improving the performance of systems involving highly flexible structures has become a topic of considerable research interest. Most of these systems are quite complicated, using multiple actuators and sensors, and possessing high order models. The majority of analytical controller synthesis procedures capable of handling multivariable systems in a systematic way require considerable insight into the underlying mathematical theory...

Topics: NASA Technical Reports Server (NTRS), ACTIVE CONTROL, ACTUATORS, CONTROL SYSTEMS DESIGN,...

A comparative study is made between the Algorithm to Architecture Mapping Model (ATAMM) and three other related multiprocessing models from the published literature. The primary focus of all four models is the non-preemptive scheduling of large-grain iterative data flow graphs as required in real-time systems, control applications, signal processing, and pipelined computations. Important characteristics of the models such as injection control, dynamic assignment, multiple node instantiations,...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, DATA FLOW ANALYSIS, MULTIPROCESSING (COMPUTERS),...

Derivation of first and second partials of the gravitational potential is given in both normalized and unnormalized form. Two different recursion formulas are considered. Derivation of a general gravity gradient torque algorithm which uses the second partial of the gravitational potential is given. Derivation of the geomagnetic field vector is given in a form that closely mimics the gravitational algorithm. Ada code for all algorithms that precomputes all possible data is given. Test cases...

Topics: NASA Technical Reports Server (NTRS), GEOMAGNETISM, GRAVITATIONAL FIELDS, LEGENDRE FUNCTIONS,...

This project investigated some properties of the AMA-32 wrist-worn activity monitor. In the first phase of this project, a software program for the analysis of activity data was developed. The program .permits rapid statistical and graphical summaries of activity data. The second phase of the project investigated effects of varying the sensitivity of the actigraph. Three different frequency passbands were investigated. The ability to differentiate sleep from wake was optimized with a 2 tO 3 Hz...

Topics: DTIC Archive, Elsmore, Timothy F, NAVAL HEALTH RESEARCH CENTER SAN DIEGO CA, *MONITORING, *SLEEP,...

Objectives of the research are: (1) to develop design requirements for damped struts to stabilize control system in the high frequency cross-over and spill-over range; (2) to design, fabricate and test viscously damped strut and viscoelastically damped strut; (3) to verify accuracy of design and analysis methodology of damped struts; and (4) to design and build test apparatus, and develop data reduction algorithm to measure strut complex stiffness. In order to meet the stringent performance...

Topics: NASA Technical Reports Server (NTRS), ACTIVE CONTROL, DESIGN ANALYSIS, FABRICATION, FLEXIBLE...

This paper presents a signal processing system that: (1) provides an efficient and reliable instrument for investigating the activity of neuronal assemblies in the brain; and (2) demonstrates the feasibility of generating the command signals of prostheses using the activity of relevant neurons in disabled subjects. The system operates online, in a fully automated manner and can recognize the transient waveforms of several neurons in extracellular neurophysiological recordings. Optimal...

Topics: NASA Technical Reports Server (NTRS), NEURONS, NEUROPHYSIOLOGY, ON-LINE SYSTEMS, SIGNAL PROCESSING,...

Dual energy x-ray absorptiometry (DXA) is currently the most widely used method of analyzing regional and whole body changes in bone mineral content (BMC) and areal (g/sq cm) bone mineral density (BMD). However, BMC and BMD do not provide direct measures of long bone geometry, structure, or strength nor do regional measurements detect localized changes in other regions of the same bone. The capabilities of DXA can be enhanced significantly by special processing of pixel BMC data which yields...

Topics: NASA Technical Reports Server (NTRS), AEROSPACE MEDICINE, BEAMS (SUPPORTS), BONE MINERAL CONTENT,...

Investigation of the correlation and gradient characteristics of the basic parameters of the ionospheric profile (foF2 and H'F) and Maximum usable frequency (MUF(3000)F2) were estimated for the aim of the creation of ionospheric model for HF radio predictions and communications. Ionospheric data on European sounding stations (Digisondes) spaced at the distances of 1000 to 1100 km from each other were used for the period in one year from September 1990 to October 1991. Various diurnal and...

Topics: DTIC Archive, Tsedilina, E E, TEL-AVIV UNIV (ISRAEL) DEPT OF GEOPHYSICS AND PLANETARY SCIENCES,...

This paper describes an 8 degree-of-freedom macro-micro robot capable of performing tasks which require accurate force control. Applications such as polishing, finishing, grinding, deburring, and cleaning are a few examples of tasks which need this capability. Currently these tasks are either performed manually or with dedicated machinery because of the lack of a flexible and cost effective tool, such as a programmable force-controlled robot. The basic design and control of the macro-micro...

Topics: NASA Technical Reports Server (NTRS), DEGREES OF FREEDOM, LOADS (FORCES), MULTIPROCESSING...

Flight Dynamics Facility (FDF) responsibilities for calibration of Upper Atmosphere Research Satellite (UARS) sensors included alignment calibration of the fixed-head star trackers (FHST's) and the fine Sun sensor (FSS), determination of misalignments and scale factors for the inertial reference units (IRU's), determination of biases for the three-axis magnetometers (TAM's) and Earth sensor assemblies (ESA's), determination of gimbal misalignments of the Solar/Stellar Pointing Platform (SSPP),...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMICS, ATTITUDE (INCLINATION), ATTITUDE INDICATORS,...

311
311

Sep 20, 2010
09/10

by
Stakkestad, Kjell; Fennessey, Richar

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The SCATHA (Spacecraft Charging at High Altitudes) satellite was operated from the Consolidated Space Test Center in Sunnyvale, California from February 1979 to May 1991. It was a spin stabilized vehicle in a highly eccentric orbit that collected data on spacecraft charging. The purpose of such data gathering was to predict and/or model the effects of the Earth's magnetic field on synchronous and near synchronous satellites. During the majority of its lifetime, attitude precession maneuvers...

Topics: ANGULAR MOMENTUM, SATELLITE INSTRUMENTS, SOLAR SENSORS, TELESCOPES, ALGORITHMS, EQUINOXES, FEEDBACK...

There are an estimated two million people with epilepsy in the United States. Many of these people do not respond to anti-epileptic drug therapy. Two devices can be developed to assist in the treatment of epilepsy. The first is a microcomputer-based system designed to process massive amounts of electroencephalogram (EEG) data collected during long-term monitoring of patients for the purpose of diagnosing seizures, assessing the effectiveness of medical therapy, or selecting patients for...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, COMPUTER TECHNIQUES, DETECTION,...

The research effort has been focused on the development of an advanced flow solver for complex viscous turbulent flows with shock waves. The three-dimensional Euler and full/thin-layer Reynolds-averaged Navier-Stokes equations for compressible flows are solved on structured hexahedral grids. The Baldwin-Lomax algebraic turbulence model is used for closure. The space discretization is based on a cell-centered finite-volume method augmented by a variety of numerical dissipation models with...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, COMPUTERIZED SIMULATION, HEAVY LIFT LAUNCH...

Interactions between structure response and control of large flexible space systems have challenged current modeling techniques and have prompted development of new techniques for model improvement. Due to the geometric complexity of envisioned large flexible space structures, finite element models (FEM's) will be used to predict the dynamic characteristics of structural components. It is widely accepted that these models must be experimentally 'validated' before their acceptance as the basis...

Topics: NASA Technical Reports Server (NTRS), DESIGN ANALYSIS, DYNAMIC CONTROL, FINITE ELEMENT METHOD,...

This paper gives an overview of the implementation of NESL, a portable nested data-parallel language. This language and its implementation are the first to fully support nested data structures as well as nested data- parallel function calls. These features allow the concise description of parallel algorithms on irregular data structures, such as sparse matrices and graphs. In addition, they maintain the advantages of data-parallel languages: a simple programming model and portability. The...

Topics: DTIC Archive, Blelloch, Guy E, CARNEGIE-MELLON UNIV PITTSBURGH PA SCHOOL OF COMPUTER SCIENCE,...

The development of a gridless computational fluid dynamics (CFD) method for the solution of the two- and three-dimensional Euler and Navier-Stokes equations is described. The method uses only clouds of points and does not require that the points be connected to form a grid as is necessary in conventional CFD algorithms. The gridless CFD approach appears to resolve the inefficiencies encountered with structured or unstructured grid methods, and consequently offers great potential for accurately...

Topics: NASA Technical Reports Server (NTRS), COMPUTATIONAL FLUID DYNAMICS, COMPUTATIONAL GRIDS, EULER...

Algorithms that reject transient signals due to proton effects on charge coupled device (CCD) sensors have been implemented in the HDOS ASTRA-l Star Trackers to be flown on the TOPEX mission scheduled for launch in July 1992. A unique technique for simulating a proton-rich environment to test trackers is described, as well as the test results obtained. Solar flares or an orbit that passes through the South Atlantic Anomaly can subject the vehicle to very high proton flux levels. There are three...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, CHARGE COUPLED DEVICES, ENVIRONMENTAL TESTS,...

Original Backprop (Version 1.2) is an MS-DOS package of four stand-alone C-language programs that enable users to develop neural network solutions to a variety of practical problems. Original Backprop generates three-layer, feed-forward (series-coupled) networks which map fixed-length input vectors into fixed length output vectors through an intermediate (hidden) layer of binary threshold units. Version 1.2 can handle up to 200 input vectors at a time, each having up to 128 real-valued...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, APPLICATIONS PROGRAMS (COMPUTERS), C (PROGRAMMING...

There is a wide range of complexity in the various telerobotic servicing tasks performed in subsea, space, and hazardous material handling environments. Experience with telerobotic servicing has evolved into a knowledge base used to design tasks to be 'telerobot friendly.' This knowledge base generally resides in a small group of people. Written documentation and requirements are limited in conveying this knowledge base to serviceable equipment designers and are subject to misinterpretation. A...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, ROBOT CONTROL, ROBOTS, TASK COMPLEXITY, TASK...

This paper considers the use of neural networks (NN's) in controlling a nonlinear, stochastic system with unknown process equations. The NN is used to model the resulting unknown control law. The approach here is based on using the output error of the system to train the NN controller without the need to construct a separate model (NN or other type) for the unknown process dynamics. To implement such a direct adaptive control approach, it is required that connection weights in the NN be...

Topics: NASA Technical Reports Server (NTRS), ADAPTIVE CONTROL, ALGORITHMS, APPROACH CONTROL, COMPLEX...

Methods for fusing two computer vision methods are discussed and several example algorithms are presented to illustrate the variational method of fusing algorithms. The example algorithms solve the photo-topography problem; that is, the algorithms seek to determine planet topography given two images taken from two different locations with two different lighting conditions. The algorithms each employ a single cost function that combines the computer vision methods of shape-from-shading and...

Topics: DTIC Archive, Thompson, Clay M, MASSACHUSETTS INST OF TECH CAMBRIDGE ARTIFICIAL INTELLIGENCE LAB,...

An enhanced grid system for the Space Shuttle Orbiter was built by integrating CAD definitions from several sources and then generating the surface and volume grids. The new grid system contains geometric components not modeled previously plus significant enhancements on geometry that has been modeled in the old grid system. The new orbiter grids were then integrated with new grids for the rest of the launch vehicle. Enhancements were made to the hyperbolic grid generator HYPGEN and new tools...

Topics: NASA Technical Reports Server (NTRS), COMPUTATIONAL GRIDS, COMPUTER AIDED DESIGN, FAR FIELDS, GRID...

The JPL Supervisory Telerobotics Laboratory (STELER) has developed a unique local-remote robot control architecture which enables management of intermittent bus latencies and communication delays such as those expected for ground-remote operation of Space Station robotic systems via the TDRSS communication platform. At the local site, the operator updates the work site world model using stereo video feedback and a model overlay/fitting algorithm which outputs the location and orientation of the...

Topics: NASA Technical Reports Server (NTRS), AUTOMATIC CONTROL, CONTROL SYSTEMS DESIGN, MANUAL CONTROL,...