Digital Commons Network^™

Robust Adaptive Critic Based Neurocontrollers For Missiles With Model Uncertainties, Zhongwu Huang, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A Lyapunov theory-based controller is proposed in this paper for robustness against model uncertainties in the control of a missile. The controller design consists of two parts; in the first phase, an optimal nonlinear controller is designed with neural networks for tracking. This is based on the adaptive critic method that consists of one neural network called the supervisor or critic and a second network called an action network or a controller. Each network is trained through the output of the other network and equations related to optimal control. When their outputs are mutually consistent, the controller network output is …

Detection And Classification Of Impact-Induced Damage In Composite Plates Using Neural Networks, Rohit Dua, Steve Eugene Watkins, Donald C. Wunsch, K. Chandrashekhara, Farhad Akhavan

Electrical and Computer Engineering Faculty Research & Creative Works

Artificial neutral networks (ANN) can be used as an online health monitoring systems (involving damage assessment, fatigue monitoring and delamination detection) for composite structures owing to their inherent fast computing speeds, parallel processing and ability to learn and adapt to the experimental data. The amount of impact-induced strain on a composite structure can be found using strain sensors attached to composite structures. Prior work has shown that strain-based ANN can characterize impact energy on composite plates and that strain signatures can be associated with damage types and severity. This paper reports the extension of this approach for damage classification using …

Amplitude Modulated Droplet Formation In High Precision Solder Droplet Printing, Qingbin Liu, M. Orme, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

There are many methods used at present to apply solder to wafers, ceramics, laminate and flex circuit boards, and other substrates. Among these, high-precision solder droplet printing technology, which is noncontact, data driven, flexible and environmentally friendly, is a key enabling technology. This technology selectively deposits solder droplets only where required, and therefore needs no mask or secondary resist removal, uses materials more efficiently and creates less waste than other methods. Currently, continuous droplet formation from capillary streams is mainly achieved by application of the well-known Rayleigh instability in which a sinusoidal disturbance is applied to the stream, resulting in …

An Optimal Control Based Treatment Strategy For Parturient Paresis Using Neural Networks, Radhakant Padhi, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An optimal online feedback treatment strategy is developed for the parturient paresis of cows, based on nonlinear optimal control theory. A limitation in the development of an existing mathematical model for calcium homeostasis is addressed and the model is extended to incorporate control inputs. An optimal feedback controller is synthesized for the nonlinear system using neural networks. Though the main aim of this paper is to solve the biomedical control problem, the methodology presented in this paper is a general computational tool, which can be applied to solve a fairly general class nonlinear optimal control problems.

Nebraska Summary 355: Agco Dt225 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1791: John Deere 9400t Also 9420t 24 Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1789: John Deere 9200 24 & 12 Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1796: Case Ih Stx 275/New Holland Tj 275 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1797: Case Ih Stx 325/New Holland Tj 325 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Tractor Test 1781: White 8510, Agco Dt160, Agco Allis 9755, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Tractor Test 1795: White 8810, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 1793: Massey Ferguson 2220 Diesel 12-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Nebraska Summary 388: Fendt 918 Vario Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

A Numerical Study Of Automotive Gas Tank Filler Pipe Two Phase Flow, R. Banerjee, Kakkattukuzhy M. Isaac, L. Oliver, W. Breig

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Automotive refueling is gaining greater importance because fuel vapors released during refueling are believed to increase ozone levels in urban areas. As a step towards On-Board Refueling Vapor Recovery (ORVR) designs, vapor generation and transport during refueling needs to be understood to develop recovery techniques. The objective of the present study is to understand the fluid flow inside the automotive gas tank filler pipe using commercially available Computational Fluid Dynamics (CFD) software. This effort is expected to yield detailed flow field information, including air entrainment. The phenomena of well-back, the process of fuel flooding the filler pipe and flowing backwards …

Finite Element Analysis And Active Control For Nonlinear Flutter Of Composite Panels Under Yawed Supersonic Flow, Khaled Abdel-Motagaly

Mechanical & Aerospace Engineering Theses & Dissertations

A coupled structural-electrical modal finite element formulation for composite panels with integrated piezoelectric sensors and actuators is presented for nonlinear panel flutter suppression under yawed supersonic flow. The first-order shear deformation theory for laminated composite plates, the von Karman nonlinear strain-displacement relations for large deflection response, the linear piezoelectricity constitutive relations, and the first-order piston theory of aerodynamics are employed. Nonlinear equations of motion are derived using the three-node triangular MIN3 plate element. Additional electrical degrees of freedom are introduced to model piezoelectric sensors and actuators. The system equations of motion are transformed and reduced to a set of nonlinear …

Future Research Vessels, Larry P. Atkinson

CCPO Publications

The academic research vessel fleet in the United States is embarking on a great experiment. By 2004 we will know if SWATH vessels such as the Mlo Moana and the possible built Woods Hole Oceanographic Institution coastal SWATH have such great advantages that all future vessels will be of SWATH design. Or, we will find that the two hull forms have distinct niches and the fleet will evolve with a strategic mix. Regardless of the Mure hull form research vessels will grow in size to accommodate advanced technology and the people to run and maintain it. The research vessel will …

Eddy Structures Induced Within A Wedge By A Honing Circular Arc, C. P. Hills

Articles

In this paper we outline an expeditious numerical procedure to calculate the Stokes flow in a corner due to the rotation of a scraping circular boundary. The method is also applicable to other wedge geometries. We employ a collocation technique utilising a basis of eddy (similarity) functions introduced by Moffatt (1964) that allows us to satisfy automatically the governing equations for the streamfunction and all the boundary conditions on the surface of the wedge. The circular honing problem thereby becomes one-dimensional requiring only the satisfaction of conditions on the circular boundary. The advantage of using the Moffatt eddy functions as …

Eddies Induced In Cylindrical Containers By A Rotating End Wall, Christopher Hills

Articles

The flow generated in a viscous liquid contained in a cylindrical geometry by a rotating end wall is considered. Recent numerical and experimental work has established several distinct phases of the motion when fluid inertia plays a significant role. The current paper, however, establishes the nature of the flow in the thus far neglected low Reynolds number regime. Explicitly, by employing biorthogonality relations appropriate to the current geometry, it is shown that a sequence of exponentially decaying eddies extends outward from the rotating end wall. The cellular structure is a manifestation of the dominance of complex eigensolutions to the homogeneous …

High Precision Solder Droplet Printing Technology: Principle And Applications, Qingbin Liu, M. Orme, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Solder droplet printing technology, which is low-cost, noncontact, flexible, data-driven, and environmentally friendly, has emerged as an enabling technology for precisely placing fine solder deposits on a variety of small substrates. It is suitable for a variety of applications including direct chip attach site preparation, 3D substrates, fine line interconnect, substrate via fill, optoelectronics and many others. It enables manufacturing techniques that are impossible or unfeasible with current technology, such as localized replacement of solder on board, depositing solder in different thicknesses on the same board, or using more than one type of solder on the same board. This makes …

Adaptive Critic Based Neuro-Observer, Xin Liu, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A new Neural Network (NN) based observer design method for nonlinear systems represented by nonlinear dynamics and linear/nonlinear measurement is proposed in this paper. In this new approach, as the first step, the observer design problem is changed into a "controller" design problem by establishing the error dynamics, and then the Adaptive Critic (AC) based approach is applied on this error dynamics to design a 'controller', such that the errors are driven to zero. The resulting observer has inherent robustness from the AC based design approach. Some simulations are presented to illustrate the effectiveness of this approach.

Microstructure-Sensitive Design Of A Compliant Beam, Brent L. Adams, Alisa J. Millar Henrie, B. Henrie, M. Lyon, H. Garmestani, Surya R. Kalidindi

Faculty Publications

BA acknowledges financial support provided by the MRSEC Program of the National Science Foundation under Award Number DMR-9632556. SK acknowledges financial support from National Science Foundation under Award Number CMS-9732699. BA, SK and HG also acknowledge support from the NSF-CIRE program centered at Florida A&M University, facilitating collaborations. Support was also provided by the College of Engineering and Technology at BYU (AH, BH and ML). Computations were performed on the new SGI Origin 2000 supercomputer at Brigham Young University, donated by Ira Fulton. We show that mechanical design can be conducted where consideration of polycrystalline microstructure as a continuous design …

Piv Measurements Of Channel Flow With Multiple Rib Arrangements, Harald Roclawski

University of Kentucky Master's Theses

A model of a gas turbine blade cooling channel equipped with turbulators and a backward facing step geometry was examined. Up to four turbulators oriented cross-stream and inclined 45° to the flow direction were mounted in the channel. The blockage ratio b/H of the turbulators and the height h/H of the backward facing step was 0:125 and 0:14 respectively. The number of turbulators as well as their size was varied. In a preliminary investigation, hot-wire and pressure measurements were taken for three different Reynolds numbers (5,000, 12,000, 18,000)in the center plane of the test section. Subsequently, particle image …

Modeling Of A Meat Cooking Process For On-Line Monitoring And Control, Oralia Garcia

Theses and Dissertations - UTB/UTPA

A heat transfer model is developed to predict cooking time of meat patties given the initial temperature of meat, oven temperature, and meat properties to monitor and control a cooking process on-line. Experiments were performed to find the cause of variability in cooked weight and raw temperature effects in forming and final cooked temperature. Advanced charting techniques concluded that only common causes of variability were present in the process. Thermal conductivity experiments were performed to determine the thermal conductivity of meat (k), which was compared with the properties of meat published in literature to validate the experiment. Oven design analysis …

Small Below-Endurance-Limit Cycle Damage Contributions In Variable Sequence Loading For 2024-T351 Aluminum Alloy, Christopher M. Ngiau

Masters Theses

It is a common practice in industry today to totally discard the presence of small below-endurance/fatigue limit cycles while calculating damage accumulation using the Palmgren-Miner rule. However, it was experimentally found in a number of studies that small cycles with stress amplitudes below the fatigue/endurance limit do in fact contribute significantly to the damage accumulation in all types of materials. There was a need to investigate cases where small cycles would only be present for a certain percentage of the material's life. An experimental study was done on 2024- T351 aluminum alloy. Loading was done in low and high cyclic …

A Growth Mixture Theory For Cartilage, Stephen M. Klisch, Robert L. Sah, Anne Hoger

Mechanical Engineering

In this paper we present a model of growth for cartilaginous tissues in which there exists a saturated solid matrix composed of multiple constituents that may grow and remodel independently of each other. Klisch and Hoger recently developed a general theory of volumetric growth for a mixture of ν-1 growing elastic materials and an inviscid fluid, which included a treatment of two special types of internal constraints that are relevant to cartilage. Here, that theory is specialized to construct a cartilage growth model. This theory allows the constituents of the solid matrix to grow independently of each other, and can …

A Comparison Of Two Actuators For A Semi-Active Helmholtz Resonator, Charles Birdsong, Clark J. Radcliffe

Mechanical Engineering

Two electro-mechanical actuators are examined for a semi-active Helmholtz resonator acoustic device. The device is used to reflect narrow band noise back to the source in an acoustic duct. The controller and actuator are used to tune the system on-line allowing optimum performance over a range of operating conditions. Actuator. dynamics play an important role in the controller design and the operation of the device. Two variations of an electro-mechanical actuator are considered here. The first uses a dual voice coil speaker with local feedback compensation and the second uses the same speaker without the compensation. It is shown that …

Surface Extrapolation Length And Director Structures In Confined Nematics, Nikolai V. Priezjev, Robert A. Pelcovits

Mechanical and Materials Engineering Faculty Publications

We report the results of Monte Carlo simulations of the Lebwohl-Lasher model of nematic liquid crystals confined to cylindrical cavities with homeotropic anchoring. We show that the ratio of the bulk to surface couplings is not in general equal to the corresponding parameter K/W used in elastic theory (where K is the Frank elastic constant in the one-constant approximation and W is the surface anchoring strength). By measuring the temperature dependence of K/W (which is equivalent to the surface extrapolation length) we are able to reconcile the results of our simulations as well as others with the predictions of elastic …

Development And Validation Of A Pedestrian Lower Limb Non-Linear 3-D Finite Element Model, Peter Schuster, Gopal Jayaraman

Mechanical Engineering

Lower limb injury is becoming an increasingly important concern in vehicle safety for both occupants and pedestrians. To enable vehicle manufacturers to better understand the biomechanical effects of design changes, it is deemed beneficial to employ a biomechanically fidelic finite element model of the human lower limb.

The model developed in this study includes long bones (tibia, fibula, femur) and flat bone (patella) as deformable bodies. The pelvis and foot bones are modeled as rigid bodies connected to the femur and tibia/fibula via rotational spring-dashpots. The knee is defined by scanned bone surface geometry and is surrounded by the menisci, …

The Hers Rating Method And The Derivation Of The Normalized Modified Loads Method, Florida Solar Energy Center, Philip W. Fairey

FSEC Energy Research Center®

This paper provides much of the historical background surrounding the contentious development of a national, uniform rating method for rating the energy-efficiency of homes. A full derivation of the most recently adopted rating method, the Normalized Modified Loads Method, is provided in detail and the issues and events leading up to the development of each of the succeeding methods are described.

Ever since the inclusion of Home Energy Rating Systems in the 1992 Energy Policy Act, the most contentious issue associated with them has been the development of a uniform rating method. To date, four succeeding methods have been proposed: …

A Study For An Optimal Delivery Sequence Of A Bowling Pinspotter Distributor Mechanism, David Michael Burt

Mechanical & Aerospace Engineering Theses & Dissertations

The two major competitors in bowling sports equipment are Brunswick, Inc., and AMF Bowling Co. The latest version of a piece of bowling equipment machinery is called a Pinspotter, the design of which has been in existence since the 1950's. With the exception of electronic scoring systems, much of the original design is still being implemented in this model. It is the desire to eliminate undesirable traits in the original Pinspotter model design. Commercial Bowling observations have detected flaws found in a piece of machinery known as the Distributor. The flaws attributed to the Distributor are believed to be sources …