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You searched for +publisher:"Georgia Tech" +contributor:("John R. Olds"). Showing records 1 – 3 of 3 total matches.

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Georgia Tech

1. Topsakal, Julide Julie. Robust Motion Planning in the Presence of Uncertainties using a Maneuver Automaton.

Degree: MS, Aerospace Engineering, 2005, Georgia Tech

One of the basic problems which have to be solved by Unmanned Automated Vehicles (UAV) involves the computation of a motion plan that would enable the system to reach a target given a set of initial conditions in presence of uncertainties on the vehicle dynamics and in the environment. Recent research efforts in this area have relied on deterministic models. To address the problem of inevitable uncertainties, a low-level control layer is typically used to ensure proper robust trajectory tracking. Such decision-tracking algorithms correct model disturbances a posteriori, while the whole movement planning is done in a purely deterministic fashion. We argue that the decision making process that takes place during movement planning, as performed by experienced human pilots, is not a purely deterministic operation, but is heavily influenced by the presence of uncertainties and reflects a risk-management policy. This research aims at addressing these uncertainties and developing an optimal control strategy that would account for the presence of system uncertainties. The underlying description of UAV trajectories will be based on a modeling language, the Maneuver Automaton, that takes into full account the vehicle dynamics, and hence guarantees flyable and trackable paths and results in a discretized solution space. Two optimal control problems, a nominal problem omitting uncertainties and a robust problem addressing the presence of uncertainties, will be defined and compared throughout this work. The incorporation of uncertainties, will ensure that the generated motion planning policies will maximize the probability to meet mission goals, weighing risks against performance. Advisors/Committee Members: Carlo L. Bottasso (Committee Chair), John R. Olds (Committee Member), Panagiotis Tsiotras (Committee Member).

Subjects/Keywords: Motion planning; Maneuver automaton; Unmanned aerial vehicles; Vehicles, Remotely piloted; Uncertainty; Robust control; Intelligent control systems; Drone aircraft

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APA (6th Edition):

Topsakal, J. J. (2005). Robust Motion Planning in the Presence of Uncertainties using a Maneuver Automaton. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/6904

Chicago Manual of Style (16th Edition):

Topsakal, Julide Julie. “Robust Motion Planning in the Presence of Uncertainties using a Maneuver Automaton.” 2005. Masters Thesis, Georgia Tech. Accessed December 15, 2019. http://hdl.handle.net/1853/6904.

MLA Handbook (7th Edition):

Topsakal, Julide Julie. “Robust Motion Planning in the Presence of Uncertainties using a Maneuver Automaton.” 2005. Web. 15 Dec 2019.

Vancouver:

Topsakal JJ. Robust Motion Planning in the Presence of Uncertainties using a Maneuver Automaton. [Internet] [Masters thesis]. Georgia Tech; 2005. [cited 2019 Dec 15]. Available from: http://hdl.handle.net/1853/6904.

Council of Science Editors:

Topsakal JJ. Robust Motion Planning in the Presence of Uncertainties using a Maneuver Automaton. [Masters Thesis]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/6904


Georgia Tech

2. Kokan, Timothy Salim. Characterizing High-Energy-Density Propellants for Space Propulsion Applications.

Degree: PhD, Aerospace Engineering, 2007, Georgia Tech

There exists wide ranging research interest in high-energy-density matter (HEDM) propellants as a potential replacement for existing industry standard fuels for liquid rocket engines. The U.S. Air Force Research Laboratory, the U.S. Army Research Lab, the NASA Marshall Space Flight Center, and the NASA Glenn Research Center each either recently concluded or currently has ongoing programs in the synthesis and development of these potential new propellants. In order to perform conceptual designs using these new propellants, most conceptual rocket engine powerhead design tools (e.g. NPSS, ROCETS, and REDTOP-2) require several thermophysical properties of a given propellant over a wide range of temperature and pressure. These properties include enthalpy, entropy, density, viscosity, and thermal conductivity. Very little thermophysical property data exists for most of these potential new HEDM propellants. Experimental testing of these properties is both expensive and time consuming and is impractical in a conceptual vehicle design environment. A new technique for determining these thermophysical properties of potential new rocket engine propellants is presented. The technique uses a combination of three different computational methods to determine these properties. Quantum mechanics and molecular dynamics are used to model new propellants at a molecular level in order to calculate density, enthalpy, and entropy. Additivity methods are used to calculate the kinematic viscosity and thermal conductivity of new propellants. This new technique is validated via a series of verification experiments of HEDM compounds. Results are provided for two HEDM propellants: quadricyclane and 2-azido-N, N-dimethylethanamine (DMAZ). In each case, the new technique does a better job than the best current computational methods at accurately matching the experimental data of the HEDM compounds of interest. A case study is provided to help quantify the vehicle level impacts of using HEDM propellants. The case study consists of the National Aeronautics and Space Administrations (NASA) Exploration Systems Architecture Study (ESAS) Lunar Surface Access Module (LSAM). The results of this study show that the use of HEDM propellants instead of hypergolic propellants can lower the gross weight of the LSAM and may be an attractive alternative to the current baseline hypergolic propellant choice. Advisors/Committee Members: Jerry M. Seitzman (Committee Co-Chair), John R. Olds (Committee Co-Chair), John A. Blevins (Committee Member), Mitchell L. Walker II (Committee Member), Peter J. Ludovice (Committee Member).

Subjects/Keywords: Propulsion; High-energy density matter; Rocket propellants; Molecular dynamics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Kokan, T. S. (2007). Characterizing High-Energy-Density Propellants for Space Propulsion Applications. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/14626

Chicago Manual of Style (16th Edition):

Kokan, Timothy Salim. “Characterizing High-Energy-Density Propellants for Space Propulsion Applications.” 2007. Doctoral Dissertation, Georgia Tech. Accessed December 15, 2019. http://hdl.handle.net/1853/14626.

MLA Handbook (7th Edition):

Kokan, Timothy Salim. “Characterizing High-Energy-Density Propellants for Space Propulsion Applications.” 2007. Web. 15 Dec 2019.

Vancouver:

Kokan TS. Characterizing High-Energy-Density Propellants for Space Propulsion Applications. [Internet] [Doctoral dissertation]. Georgia Tech; 2007. [cited 2019 Dec 15]. Available from: http://hdl.handle.net/1853/14626.

Council of Science Editors:

Kokan TS. Characterizing High-Energy-Density Propellants for Space Propulsion Applications. [Doctoral Dissertation]. Georgia Tech; 2007. Available from: http://hdl.handle.net/1853/14626


Georgia Tech

3. Kalaver, Satchidanand Anil. Management of Reference Frames in Simulation and its Applications.

Degree: PhD, Aerospace Engineering, 2006, Georgia Tech

The choice of reference frames used in simulations is typically fixed in dynamic models based on modeling decisions made early during their development, restricting model fidelity, numerical accuracy and integration into large-scale simulations. Individual simulation components typically need to model the transformations between multiple reference frames in order to interact with other components, resulting in additional development effort, time and cost. This dissertation describes the methods for defining and managing different reference frames in a simulation, thereby creating a shared simulation environment that can provide reference frame transformations, comprising of kinematics and rotations, to all simulation components through a Reference Frame Manager. Simulation components can use this Reference Frame Manager to handle all kinematics and rotations when interacting with components using different reference frames, improving the interoperability of simulation components, especially in parallel and distributed simulation, while reducing their development time, effort and cost. The Reference Frame Manager also facilitates the development of Generic Dynamic Models that encapsulate the core service of dynamic model, enabling the rapid development of dynamic models that can be reused and reconfigured for different simulation scenarios and requirements. The Reference Frame Manager can also be used to introduce Intermediate Frames that bound the magnitudes of vehicle states, reducing roundoff error and improving numerical accuracy. Advisors/Committee Members: Dr Amy R Pritchett (Committee Chair), Dr Angus L. McLean (Committee Member), Dr Dewey H. Hodges (Committee Member), Dr Eric N. Johnson (Committee Member), Dr John R. Olds (Committee Member).

Subjects/Keywords: Reference frames; Simulation; Dynamic model; Numerical error; Distributed simulation

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Kalaver, S. A. (2006). Management of Reference Frames in Simulation and its Applications. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/10492

Chicago Manual of Style (16th Edition):

Kalaver, Satchidanand Anil. “Management of Reference Frames in Simulation and its Applications.” 2006. Doctoral Dissertation, Georgia Tech. Accessed December 15, 2019. http://hdl.handle.net/1853/10492.

MLA Handbook (7th Edition):

Kalaver, Satchidanand Anil. “Management of Reference Frames in Simulation and its Applications.” 2006. Web. 15 Dec 2019.

Vancouver:

Kalaver SA. Management of Reference Frames in Simulation and its Applications. [Internet] [Doctoral dissertation]. Georgia Tech; 2006. [cited 2019 Dec 15]. Available from: http://hdl.handle.net/1853/10492.

Council of Science Editors:

Kalaver SA. Management of Reference Frames in Simulation and its Applications. [Doctoral Dissertation]. Georgia Tech; 2006. Available from: http://hdl.handle.net/1853/10492

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