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Theses and Dissertations

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Verification And Validation Of The Simulated Radar Image (Srim) Code Radar Cross Section Predictions, Dale A. Stanley Dec 1991

Verification And Validation Of The Simulated Radar Image (Srim) Code Radar Cross Section Predictions, Dale A. Stanley

Theses and Dissertations

The objectives of this study were to verify and validate the Simulated Radar Image (SRIM) Code Version 4.0 monostatic radar cross section (RCS) predictions. SRIM, uses the theory of Physical Optics (PO) to predict backscatter for a user specified aspect angle. Target obscuration and multiple reflections are taken into account by sampling the target with ray tracing. The software verification and validation technique followed in this study entailed comparing the code predictions to closed from PO equations, other RCS prediction software packages, and measured data. The targets analyzed were a sphere, rectangular flat plate, circular flat plate, solid right circular …

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Face Recognition With The Karhunen-Loeve Transform, Pedro F. Suarez Dec 1991

Face Recognition With The Karhunen-Loeve Transform, Pedro F. Suarez

Theses and Dissertations

The major goal of this research was to investigate machine recognition of faces. The approach taken to achieve this goal was to investigate the use of Karhunen-Loe've Transform (KLT) by implementing flexible and practical code. The KLT utilizes the eigenvectors of the covariance matrix as a basis set. Faces were projected onto the eigenvectors, called eigenfaces, and the resulting projection coefficients were used as features. Face recognition accuracies for the KLT coefficients were superior to Fourier based techniques. Additionally, this thesis demonstrated the image compression and reconstruction capabilities of the KLT. This theses also developed the use of the KLT …

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Real Imagery As A Three Dimensional Display, Juan C. Echeverry Dec 1991

Real Imagery As A Three Dimensional Display, Juan C. Echeverry

Theses and Dissertations

This research effort implemented two 3-D display designs to assess their performance and effect on an observer's depth perception. Both 3-D displays produced real images for the observer to view. The first display setup combined a lens relay with a two concave mirror projector. The second display setup combined the two concave mirror projector with a diffuser. The lens relay/ two concave mirror projector combination was successful in imaging a source from the CRT to a point in space above the two mirror system. The problem was that the observer could not assess the image location by just looking at …

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An Investigation Of The Application Of Artificial Neural Networks To Adaptive Optics Imaging Systems, Andrew H. Suzuki Dec 1991

An Investigation Of The Application Of Artificial Neural Networks To Adaptive Optics Imaging Systems, Andrew H. Suzuki

Theses and Dissertations

Recurrent and feedforward artificial neural networks are developed as wavefront reconstructors. The recurrent neural network studied is the Hopfield neural network and the feedforward neural network studied is the single layer perceptron artificial neural network. The recurrent artificial neural network input features are the wavefront sensor slope outputs and neighboring actuator feedback commands. The feedforward artificial neural network input features are just the wavefront sensor slope outputs. Both artificial neural networks use their inputs to calculate deformable mirror actuator commands. The effects of training are examined.

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Performance Analysis Of The Speckle Holography Image Reconstruction Technique, Rudolf N. Vonniederhausern Dec 1991

Performance Analysis Of The Speckle Holography Image Reconstruction Technique, Rudolf N. Vonniederhausern

Theses and Dissertations

In speckle holography, short exposures frames along with wave front measurements allow post processing image reconstruction. With speckle holography the amplitude of high spatial frequencies is boosted to allow resolution out to the diffraction limit of the telescope. To provide system parameters for the wave front sensor design, a software analysis program has been developed that provides the system transfer function as a function of the number and size of sensor subapertures and sensor noise. Trends in the ratio of the atmospheric coherence diameter to wave front subaperture size and the effect on the system transfer function have been obtained. …

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Optical Image Segmentation Using Wavelet Correlation, Steven D. Pinski Dec 1991

Optical Image Segmentation Using Wavelet Correlation, Steven D. Pinski

Theses and Dissertations

This research introduces an optical method of segmenting potential targets using wavelet analysis. Implementation of an optical Harr wavelet is fulfilled using a magneto-optic spatial light modulator (MOSLM). Two methods of controlling wavelet dilation are explored: (1) spatial filtering of a ternary modulated MOSLM; (2) a single aperture positioned in front of a binary modulated MOSLM. Segmentation is performed through Vander Lugt correlation of a binarized image with a binarized optical wavelet. Three different image binarization methods are investigated for use in the correlation scheme: (1) average pixel value over an entire scene; (2) localized 4 x 4 pixel average …

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Low Temperature Photoluminescence Study Of Silicon-Germanium Alloy Superlattices, Maxwell M. Chi Dec 1991

Low Temperature Photoluminescence Study Of Silicon-Germanium Alloy Superlattices, Maxwell M. Chi

Theses and Dissertations

Low temperature photoluminescence studies were performed on nine silicon germanium alloy superlattice samples. The luminescence spectra showed sharp peaks in the 0.95 to 1.05 eV energy range, and a broad band located 0.05 to 0.12 eV below the alloy bandgap. The sharp peaks were identified as transitions associated with impurity bound excitons. The linewidth was about 10 times that in pure silicon; in addition, the peaks shifted to lower energy as the sample temperature was raised from 1.4 to 15 K. These features were attributed to effects of random distribution of atoms in the alloy. The broad band shifted to …

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An Analysis Of One-Dimensional Models Of The Insulating And Conducting Priz, Joseph W. Cook Iii Dec 1991

An Analysis Of One-Dimensional Models Of The Insulating And Conducting Priz, Joseph W. Cook Iii

Theses and Dissertations

This study attempted to analytically reproduce experimental and analytical data, on the single-insulated and conducting PRIZ, presented in 1987 and 1988 by the Soviet scientists Bliznetsov et al. Our onedimensional analytical models, derived from earlier Soviet reports, have consistently reproduced previously reported data on the PRIZ. In this study, the same codes were successfully used to analyze the effects of injection at high and low intensity exposures (30 µW/cm2 to 500 mW/cm2) Although the codes qualitatively duplicated the nature of the space charge distribution in the single-insulated and conducting PRIZ, our quantitative results were significantly different from …

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Self-Pumped Phase-Conjugate Twyman-Green Interferometry Using A Batio3 Crystal, Deborah A. Determan Dec 1991

Self-Pumped Phase-Conjugate Twyman-Green Interferometry Using A Batio3 Crystal, Deborah A. Determan

Theses and Dissertations

The Air Force uses optical imaging systems in many fields such as communications, target recognition, and missile guidance. For proper execution of these applications, the optical imaging systems use in these fields must be of extremely high quality so that an ideal image is obtained. In divergent beam configurations, this type of interferometer would eliminate the need for high quality reference optics needed in conventional Twyman-Green interferometry. The objective of this thesis is to demonstrate phase conjugate Twyman-Green interferometry using a barium titanate (BaTiO3) crystal as the phase conjugating mirror in the reference arm of the interferometer and …

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Photoluminescence Spectroscopy Of Mbe Grown Gallium Antimonide, John A. Dorian Dec 1991

Photoluminescence Spectroscopy Of Mbe Grown Gallium Antimonide, John A. Dorian

Theses and Dissertations

Experimental data are presented for the energy levels of the native acceptor and bound exciton emissions of GaSb grown by MBE and studied with low temperature photoluminescence (PL) spectroscopy. The undoped GaSb emissions showed a donor-acceptor pair transition with an observed emission peak at 776 meV, a peak at 716 meV usually associated with the ionization level of the acceptor, and bound exciton transitions in the energy range from 796 to 804 meV. Other unidentified peaks were observed at about 805 meV. Temperature and power dependence studies of the acceptor peak confirmed donor-acceptor pair (DAP) behavior. A GaSb sample grown …

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Silicon Carbide Thin Film Deposition By Reactive Ion-Beam Sputtering, Larry G. Sills Dec 1991

Silicon Carbide Thin Film Deposition By Reactive Ion-Beam Sputtering, Larry G. Sills

Theses and Dissertations

In this study, hydrogenated amorphous silicon carbide thin films were deposited by reactive ion-beam sputtering under varying conditions to determine whether a film's optical properties can be controlled, focusing on refractive index. Using a Kaufman type ion source to sputter a pure silicon target, three distinct series of films were grown. The first series varied the mixture of methane and argon used in the ion-beam. holding all other parameters constant. For the second series the gas mix was fixed, and only the beam energy (beam voltage) was varied. The final series also varied beam energy, but was grown with a …

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Vibrational Energy Transfer In Bromine Monofluoride, Tim L. Thompson Dec 1991

Vibrational Energy Transfer In Bromine Monofluoride, Tim L. Thompson

Theses and Dissertations

Bromine monofluoride (BrF), an interhalogen molecule, is a prospective chemical laser candidate. This study continues research begun in characterizing radiative and collisional dynamics in BrF. Vibrational energy transfer of BrF is studied using time resolved laser induced fluorescence (LIF) techniques and observing the spectrally resolved emission. First, vibrational transfer induced by the BrF production mix is determined to follow the Montroll- Shuler model and Landau-Teller scaling with a fundamental rate coefficient of kv(1,0) = (4.0) x 10-12 cm3/(molecules seconds). Also, rate coefficients for the rare gases were found to scale with the reduced mass of the collision …

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An Analysis Of Tracking And Impact Predictions, Susanne V. Lefebvre Dec 1991

An Analysis Of Tracking And Impact Predictions, Susanne V. Lefebvre

Theses and Dissertations

The accuracy of the United States Space Command's early Tracking and Impact Predictions and its OPREP-3 report initiation procedure are analyzed. The study involves satellites which decayed between 1987 and 1990. Each of the early decay predictions are compared to the final prediction with the resulting time error compared to the accuracy level asserted by the Space Surveillance Center. The results of this study indicate that the accuracy of the decay predictions is usually, but not always, within the asserted accuracy level. The results also suggest the existence of a positive bias indicating that the early decay predictions are routinely …

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A Topographical Analysis Of The Human Electroencephalogram For Patterns In The Development Of Motion Sickness, George S. Vogen Dec 1991

A Topographical Analysis Of The Human Electroencephalogram For Patterns In The Development Of Motion Sickness, George S. Vogen

Theses and Dissertations

A topographical analysis was performed on 12 electroencephalograms (EEGs) collected from 10 volunteers who experienced motion sickness through cross-coupled Coriolis stimulation. Seven males and three females participated in the research conducted at the Air Force Institute of Technology, Wright- Patterson AFB. Two male volunteers participated in double-blind placebo/ phenytoin trials. Static brain maps and dynamic EEGs which focused on delta (below 3Hz) activity during the development of motion sickness revealed a seizure-like propagation pattern. With initial symptoms, a clear left parietal focus was seen in all records. A less dominant left fronto-temporal focus was present in 11 of the 12 …

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Radar System Classification Using Neural Networks, David M. Cameron Dec 1991

Radar System Classification Using Neural Networks, David M. Cameron

Theses and Dissertations

This study investigated methods of improving the accuracy of neural networks in the classification of large numbers of classes. A literature search revealed that neural networks have been successful in the radar classification problem, and that many complex problems have been solved using systems of multiple neural networks. The experiments conducted were based on 32 classes of radar system data. The neural networks were modelled using a program called the Neural Graphics Analysis System. It was found that the accuracy of the individual neural networks could be increased by controlling the number of hidden nodes, the relative numbers of training …

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Improving Stochastic Communication Network Performance: Reliability Vs. Throughput, Leonard J. Jansen Dec 1991

Improving Stochastic Communication Network Performance: Reliability Vs. Throughput, Leonard J. Jansen

Theses and Dissertations

This research investigated the measurement and improvement of two performance parameters, expected flow and reliability, for stochastic communication networks. There were three objectives of this research. The first was to measure the reliability of large stochastic networks. This was accomplished through an investigation into the current methodologies in the literature, with a subsequent selection and application of a factoring program developed by Page and Perry. The second objective was to develop a reliability improvement model given that a mathematical reliability expression did not exist. This was accomplished modeling a heuristic by Jain and Gopal, into a linear improvement model. Finally, …

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Binary Programming Models Of Spatial Pattern Recognition: Applications In Remote Sensing Image Analysis, Thomas G. Reed Dec 1991

Binary Programming Models Of Spatial Pattern Recognition: Applications In Remote Sensing Image Analysis, Thomas G. Reed

Theses and Dissertations

The major purpose of this investigation was to implement subregion allocation objectives using a network model base on an existing subregion allocation binary programming model (Benabdallah and Wright (B&W), 1990), the ultimate goal being the application of subregion allocation concepts towards the spatial analysis of satellite imagery. The multi-objective aspects of subregion allocation can be accomplished via a network formulation, a formulation vastly simpler in complexity than the binary programming models previously used. Without a network programming package that could maintain integral flows, however, deriving the solution was a tiresome task for the user. Nonetheless, several new concepts and advantages …

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Preliminary Design Of A Model To Assess The Effect Of Space Surveillance Network (Ssn) Sensor Upgrades On Orbit Prediction Accuracies Relative To The U. S. Anti-Satellite (Asat) Mission, Daniel L. O'Brien Dec 1991

Preliminary Design Of A Model To Assess The Effect Of Space Surveillance Network (Ssn) Sensor Upgrades On Orbit Prediction Accuracies Relative To The U. S. Anti-Satellite (Asat) Mission, Daniel L. O'Brien

Theses and Dissertations

This study gives a basis for implementation of a model to assess the effect of proposed sensor upgrades to the Space Surveillance Network (SSN) to determine if more accurate orbital element set predictions by the Space Surveillance Center (SSC) can be obtained for U.S. anti-satellite (ASAT) targeting. Handoff orbital element set predictions to nearby ASAT facilities for single, low-orbit satellite passes over a single radar sensor are considered. Model development began with simulation of the selected satellites passing over the selected sensors producing baseline truth observations based on the NORAD simplified General Publications (SGP4) model. Sensor errors, in the form …

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Reducing Requirements Errors Through The Use Of Computer-Aided Software Engineering (Case) Tools And During Requirements Analysis, Marvin B. Key Jr. Dec 1991

Reducing Requirements Errors Through The Use Of Computer-Aided Software Engineering (Case) Tools And During Requirements Analysis, Marvin B. Key Jr.

Theses and Dissertations

This study investigated whether using CASE tools in the requirements analysis phase of software development reduced the software coding errors attributable to requirement analysis. A survey of the population gathered data as to the current practices and efforts in the use of CASE tools. The data was gathered in two groups: a control group and a sample group. The data was analyzed by group and in various combinations to obtain a greater understanding into population trends and tendencies. The results of the research indicate that the Air Force does not use CASE tools to any great extent. Also, error and …

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A Formal Definition Of The Object-Oriented Paradigm For Requirements Analysis, Andrew D. Boyd Dec 1991

A Formal Definition Of The Object-Oriented Paradigm For Requirements Analysis, Andrew D. Boyd

Theses and Dissertations

This paper develops a formal definition of the Object-Oriented paradigm for requirements analysis. The literature was surveyed for both formal and informal methods for conducting an Object-Oriented Requirements Analysis (OORA). The informal methods reviewed are: Bailin's, Shlaer and Mellor's, Booch's, and Coad and Yourdon's. The formal methods reviewed are: Bralick's, Z, and REFINE. None of the methods were found to be adequate for doing an OORA. A formal definition of an OORA, based on the concept of classes, is developed. The definition itself is presented as set and relation theory. A supporting graphical representation is also developed and presented. The …

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An Investigation Into The Use Of Computer-Assisted Instruction To Present Basic English Grammar Concepts, Frank E. Jones Dec 1991

An Investigation Into The Use Of Computer-Assisted Instruction To Present Basic English Grammar Concepts, Frank E. Jones

Theses and Dissertations

The purpose of this research was to develop a computer-assisted instruction (CAI) tutorial that would address basic grammatical concepts. The research consisted of four phases. The first phase was a review of applicable CAI literature, including theories, instructional and programming techniques, and previous research findings. The second phase was a survey of communication professors to determine the grammatical errors commonly committed by students. The third phase involved development of the tutorial content and the program software. The resulting tutorial presents basic grammar in terms of the three building elements of language (words, phrases, clauses) and the five functions they perform …

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Investigative Search Of Quality Historical Software Support Cost Data And Software Support Cost-Related Data, Brent L. Barber Dec 1991

Investigative Search Of Quality Historical Software Support Cost Data And Software Support Cost-Related Data, Brent L. Barber

Theses and Dissertations

The purpose of the study was to determine what software support cost data and software support cost-related data should and can be collected by the Air Force. In addition, the study was to determine how the subject data should be collected. The collection of this data is necessary in order to measure the accuracy and calibration requirements of the software support cost models used by the Air Force. The study found there was no standard set of data items, and no standard procedures in place for the collection of this data. In most cases data were available or easily accessible, …

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Software Cost Estimating Models: A Calibration, Validation, And Comparison, Gerald L. Ourada Dec 1991

Software Cost Estimating Models: A Calibration, Validation, And Comparison, Gerald L. Ourada

Theses and Dissertations

This study was a calibration, validation and comparison of four software effort estimation models. The four models evaluated were REVIC, SASET, SEER, and COSTMODL. A historical database was obtained from Space Systems Division, in Los Angeles, and used as the input data. Two software environments were selected, one used to calibrate and validate the models outside their environment of calibration. REVIC and COSTMODL are COCOMO derivatives and were calibrated using Dr. Boehm's procedure. SASET and SEER were found to be un-calibratable for this effort. Accuracy of all the models was significantly low; none of the models performed better against the …

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Structured Hypermedia Application Development Model (Shadm): A Structured Model For Technical Documentation Application Design, Peter W. Cassell Dec 1991

Structured Hypermedia Application Development Model (Shadm): A Structured Model For Technical Documentation Application Design, Peter W. Cassell

Theses and Dissertations

This research was conducted to determine how a Royal Australian Air Force technical maintenance publication could be transformed into a task oriented hypermedia application and to develop a model that could be used for future similar transformations. The model was developed following in-depth analysis of the existing USAF F-15E maintenance publication set and validation was conducted using a prototype developed in HyperWriter, a commercial hypermedia product. The prototype model was based around the performance of three maintenance tasks on an aircraft sub-subsystem and incorporated online user access to the necessary support data for task completion. Publication managers, producers, and users …

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Relative Utility Of Selected Software Requirement Metrics, James H. Byers Dec 1991

Relative Utility Of Selected Software Requirement Metrics, James H. Byers

Theses and Dissertations

The objective of this study was to determine the relative utility of selected software requirement metrics in assessing the productivity of the software requirements analysis process and the quality of the products of this process. This objective was met by collecting information about the perceptions that practicing software professionals have of the usefulness of various requirement metrics. The study employed a two part methodology. The first part utilized Basili's goal/question/metric paradigm to identify specific goals of the measurement effort and to identify requirement metrics worthy of further investigation. The second part employed a typical research design to gather perceptions that …

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A Top-Down Performance Analysis Of A Pegasus-Based Space Strike System, Douglas E. Collins Dec 1991

A Top-Down Performance Analysis Of A Pegasus-Based Space Strike System, Douglas E. Collins

Theses and Dissertations

The feasibility of using Pegasus launch vehicle as a conventional weapons platform is examined. Using a top-down approach, the analysis addresses the fundamental question of whether such a system should be considered for development. The measures of effectiveness considered are delivery range, probability of destroying the target, and responsiveness. Each of the measures is assessed at its top-level and analyzed only to the level of detail needed to address the fundamental question. The study indicates that attaining a high probability of destroying the target requires extremely precise control over the burnout conditions and that the system must be on constant …

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An Approach For The Distance Delivery Of Afit/Ls Resident Degree Curricula, Mark C. Harris Dec 1991

An Approach For The Distance Delivery Of Afit/Ls Resident Degree Curricula, Mark C. Harris

Theses and Dissertations

This research developed an approach for adapting a resident graduate course, offered by the School of Systems and Logistics, for delivery to remote students through distance education resources and techniques. A review of literature-along with personal interviews of professionals from the fields of education, telecommunications, and technology-provided the information for a model of distance education and an assessment of AFIT's existing and near future resources that may be applied to distance delivery of graduate courses. Semantic network construction software was used to organize the information gathered for the distance education model. Key concepts were distilled from the conceptually multi-dimensional semantic …

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Computation Of Planar Store Trajectories Using An Adaptive Grid Procedure, William D. Hack Dec 1991

Computation Of Planar Store Trajectories Using An Adaptive Grid Procedure, William D. Hack

Theses and Dissertations

The objective of this research was to compare a quasi-analytical, potential flow/three-degree-of-freedom model to an implicit-Euler algorithm for the calculation of store trajectories. The implicity algorithm uses a cell- centered, finite-volume, spatial discretization applied to the Euler equations, written in time-dependent, curvilinear-coordinates. A flux-differencing Roe scheme is employed to find the split-fluxes and the Steger/Warming flux-vector method is used to calculate the flux-Jacobians. The potential flow and implicit- Euler algorithm are combined with a three-degree-of-freedom algorithm to evaluate the planar, freefall trajectories of a simple store shape. The research uses two different grid-modification techniques in the implicit algorithm evaluation. Data …

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Investigation Of A Flux-Difference-Splitting Numerical Method In Supersonic Nozzles, Danny P. Allen Dec 1991

Investigation Of A Flux-Difference-Splitting Numerical Method In Supersonic Nozzles, Danny P. Allen

Theses and Dissertations

This research investigated the effects of adding a second-order flux- difference-splitting (FDS) correction term to an existing computer code that is based on a first-order FDS algorithm. It was determined that the second-order algorithm did improve the accuracy of the code for a source flow analysis, but second-order behavior could not be confirmed by the error convergence patterns. It was also discovered that, when tested across an oblique shock wave, the second-order correction terms had minimal influence on the accuracy and shock capturing ability of the first-order accurate FDS method.

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Comparison Of Pointing Control Systems Utilizing Dahl And Coulomb Friction Model Compensation, Whitney J. Hulett Dec 1991

Comparison Of Pointing Control Systems Utilizing Dahl And Coulomb Friction Model Compensation, Whitney J. Hulett

Theses and Dissertations

Bearing friction can be accurately modeled using the Coulomb friction model, provided the bearing is running. In an application where the bearing is rotated only a very small amount, the bearing does not actually rotate. Instead, the bearing undergoes plastic deformation. A nonlinear friction model was developed by P. R. Dahl of the Aerospace Corporation in the late sixties which addresses this region of placticity or compliance zone. Two friction compensation schemes for a single axis position servomechanism were developed and compared in this study. The first compensator was an integral control regulator/estimator which used the Coulomb friction model. The …

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