Mechanical Engineering Commons^™

An Adaptive Tool-Based Telerobot Control System, Ge Zhang

Doctoral Dissertations

Modern telerobotics concepts seek to improve the work efficiency and quality of remote operations. The unstructured nature of typical remote operational environments makes autonomous operation of telerobotic systems difficult to achieve. Thus, human operators must always remain in the control loop for safety reasons. Remote operations involve tooling interactions with task environment. These interactions can be strong enough to promote unstable operation sometimes leading to system failures. Interestingly, manipulator/tooling dynamic interactions have not been studied in detail. This dissertation introduces a human-machine cooperative telerobotic (HMCTR) system architecture that has the ability to incorporate tooling interaction control and other computer assistance …

Design And Parameter Identification Of A Discrete Variable Transmission System, Kelley Parker Brown

Masters Theses

Complex and expensive electro-hydraulic systems have shouldered the workload for remote cleanup operations in radiological and toxicological areas in the past; the payload, reach and speed requirements of most applications have demanded their use. Electromechanically actuated systems (EAS) however offer an alternative that in comparison is much more reliable and maintainable. The problems faced in implementing the EAS are in high payload operations where the hydraulic systems hold a clear power density advantage. For the EAS to compete in the area of torque, very large DC motors have been implemented which make them obsolete in restricted work space areas and …

Retrieval Of Nano-Size Particles From A Solid Substrate, Krishna Prasad Podila

Masters Theses

The retrieval of nano-size particles from suspects and crime scenes can significantly enhance surveillance and crime investigation. The Thesis deals with extensive study of free surface energy coupled with Hertzian contact energy under different conditions between a nano-sized particle and a substrate and the various methods of dislodging the particle. Using the Johnson-Kendall-Roberts (JKR) theory, a physical spring-mass-damper model is defined. Mathematical equations are formulated and solved with non-linear equations simulating the real world situation. Using Newmark’s β method, the system is solved for response of free and forced vibrations taking moisture to be responsible for damping. Key assumptions such …

Effects Of Pressure And Equivalence Ratio On Minimum Ignition Energies Of Methane-Air Mixtures And Effect Of Pressure On Breakdown Threshold Energies Of Methane And Air, Sameer Vidyadhar Bondre

Masters Theses

An experimental investigation is conducted to determine the effect of pressure on breakdown threshold energies of methane and air. In addition the effect of pressure and equivalence ratios on minimum ignition energies of methane-air mixtures are also investigated. The pressures for the breakdown threshold energy experiments are varied from 0.02 to 1.17 MPa, and pressures and equivalence ratios for minimum ignition energy experiments are varied from 0.1 to 1.04 MPa and 0.6 to 1.2, respectively. The gas breakdown and the ignition of the methane-air mixture is achieved using a laser-induced spark from a 5.5 ns pulse Q-switched Nd:YAG laser at …

Cure Behavior Study And Elastic Modulus Characterization Of Resin System Of A Quasi Poloidal Stellarator Modular Coil, Hariharanath Kavuri

Masters Theses

Composites materials are increasingly becoming choice materials because of their tremendous strength-to-weight properties and impressive design flexibility. A more recent application of composites is in nuclear fusion reactors. One such reactor is the Quasi-Poloidal Stellarator (QPS) being developed by Oak Ridge National laboratory. QPS, with a non-axisymmetric, near-poloidally symmetric magnetic configuration, has stranded copper/epoxy composite coils, used for magnetic confinement of plasma. CTD- 404 and CTD-101K are the resins under consideration for the modular coils with copper fiber as reinforcement. Structural integrity of the modular coils over wide range of temperatures, including liquid nitrogen temperature, is of vital importance and …

Lean Nox Trap Catalysis For Lean Burn Natural Gas Engines, Aaron Michael Williams

Masters Theses

As the nation’s demand for energy grows along with concern for the environment, there is a pressing need for cleaner, more efficient forms of energy. The internal combustion engine is well established as one of the most reliable forms of power production. They are commercially available in power ranges from 0.5 kW to 6.5 MW, which make them suitable for a wide range of distributed power applications from small scale residential to large scale industrial. In addition, alternative fuels with domestic abundance, such as natural gas, can play a key role in weaning our nations dependence on foreign oil. Lean …

Analytical And Computational Model For Aortic Hemodynamics Accounting For Aortic Elasticity And Arterial Branch-Flow Effects, Amber Adriann Hensley Edwards

Masters Theses

The causes of atherosclerotic plaque formation in the abdominal aorta has been researched for many years. It has been hypothesized that certain hemodynamic factors, such as wall shear stress, blood velocity, and blood pressure, may play an important role in its development. In order to study these properties, several models have previously been developed to try and simulate blood flow through the abdominal section of the aorta since it is at this location along the length of the aorta where the greatest incidence of atherosclerosis is known to occur. Many of these models depict the abdominal aorta as being a …

Design And Analysis Of A Low Production Cost Hybrid Electric High Mobility Multi-Purpose Wheeled Vehicle For Military Use, Craig Blake Rutherford

Masters Theses

The conceptual design of a low production cost hybrid electric High Mobility Multipurpose Wheeled Vehicle (HMMWV) is described. The design uses a parallel hybrid configuration incorporating a reduced displacement diesel engine, a permanent magnet electric motor, and lead-acid batteries. The design is termed “low production cost” because it uses commercial off the shelf (COTS) hardware where possible and does not require major alterations to either the chassis or drivetrain of the base vehicle. Computer modeling and simulation of the proposed design indicates that it can meet or exceed Army provided hybrid electric HMMWV performance criteria. The proposed design offers improved …

Design Optimization Of Enriched Water Targets, Sampath Telikicherla Kandala

Masters Theses

The purpose of this research project is to design and optimize the enriched water targets used in the cyclotron systems that are manufactured by CTI Inc. Enriched water target is the source of Fluorine 18 that is used in the Positron Emission Tomography (PET) scanners for medical imaging purposes. Oxygen 18 enriched water is the target for the 10.5 MeV protons that are produced by the cyclotron. A p-n reaction takes place when the high-energy protons interact with the Oxygen 18, creating Fluorine 18. The proton beam also deposits thermal energy in the target. As the enriched water is costly, …

Compressed Air-Driven Tests Of A Prototype TurbxTm Engine, Frederick John Mottley

Masters Theses

A century of research of existing thermodynamic cycles has developed piston engines exceeding 40% efficiency and open cycle gas turbine engines approaching 30% practical efficiency. A breakthrough engine concept has been invented by Dr. Michael Wilson (US Patents 5,966,927 and 6,105,359) and is called the TurbX^TM engine. This new engine, operating on the Atkinson cycle, can theoretically increase engine performance and fuel economy, and reduce emissions as compared to the open cycle gas turbine.

The TurbX™ engine implements a constant volume, continuous combustion process in rotating turbo-machinery. Based on a theoretically ideal thermodynamic analysis, this novel innovation will always …

Thermal Modeling And Verification Of A Quasi-Poloidal Stellarator Modular Coil, Anuj Chaudhri

Masters Theses

Controlled nuclear fusion has been the subject of experimental and analytical studies for more than forty years. A focus of research in this area has been plasma confinement using a toroidal magnetic field. The two important fusion devices used for this purpose are Tokamaks and Stellarators. The Quasi Poloidal Stellerator (QPS) is a low-aspect ratio toroidal magnetic confinement device used to contain the plasma so that Controlled Thermonuclear Reactions (CTR) can take place. An integral part of an Oak Ridge National Laboratory QPS design is the modular coil, which provides the primary magnetic field in the configuration. Since the …

Instrumentation Development For Assessing The Environment Inside Shipping Containers Of Pancreatic Islets During Air Transportation, Jeffrey Scott Rogers

Masters Theses

This study was conducted to obtain information on the effect of altitude on the internal environment of shipping containers for pancreatic islet cells being transported by commercial aircraft. Previous experience has shown that islet cell counts decrease after the islet cells have been transported by air and received at their point of destination.

A data acquisition system was designed to gather fundamental data for use in the analysis of the effects of the environment inside the containers holding the pancreatic islet cell samples being shipped by either ground or air transport, or both. A test apparatus, which fits the existing …

Developing A Feedback Control System Using Electromagnets To Increase The Stiffness Of A Circular Saw Blade, Nicholas M. Sullivan

Masters Theses

This document covers the research performed in developing a feedback control system using electromagnets to increase the stiffness of a circular saw blade. A finite element analysis was performed in a model of a saw blade to determine there the electromagnets should be placed relative to the new saw blade. Experimental tests were performed with each component of the system to determine their characteristics. A mathematical model of the complete feedback control system was developed in Simulink. Various tests were performed to determine what parameters could be changed in order to get the desired response out of the system. A …

Mechanical Design And Analysis Of A Discrete Variable Transmission System For Transmission-Based Actuators, Sriram Sridharan

Masters Theses

Over the past few years, replacing the hydraulic servo actuators with their electrical counter parts for robotics and remote handling systems has been an active field of research. These systems are of particular interest for tasks involved with the US Department of Energy, where the level of radiation exposure is high and the tasks are highly repetitive. With the hydraulic servo actuators, one is concerned with the issues like the high complexity, cost of the system and the difficulty of maintenance of the system. For high payload operations, the hydraulic systems provide an order of magnitude increase in the power …