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Effect of coordinate switching on simulation accuracy of translunar trajectoriesVautier, Mana P., Sinclair, Andrew J., January 2008 (has links) (PDF)
Thesis (M.S.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 48-49) and index.
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An efficient algorithm for computing the low-thrust escape trajectory /Gall, John A. January 2004 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 59-61). Also available on the Internet.
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An efficient algorithm for computing the low-thrust escape trajectoryGall, John A. January 2004 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 59-61). Also available on the Internet.
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Contouring control in high performance motion systems /Chen, Ni. January 2005 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 81-86). Also available in electronic version.
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The derivation of an effective string theory from a field theory containing vortex solutions, and its application to Regge trajectories /Steinke, Ronald, January 2000 (has links)
Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (p. 92-96).
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Nucleon isobar production.Rice, John Lawrence. January 1967 (has links)
No description available.
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The optimisation of low thrust satellite trajectoriesMaany, Z. A. January 1986 (has links)
No description available.
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Quantum studies of molecular dynamicsSutcliffe, Julia H. January 1995 (has links)
No description available.
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Optimal trajectory reconfiguration and retargeting for the X-33 reusable launch vehicleShaffer, Patrick J. 09 1900 (has links)
Approved for public release; distribution is unlimited / This thesis considers the problem of generating optimal entry trajectories for a reusable launch vehicle following a control surface failure. The thesis builds upon the work of Dr. David Doman, Dr. Michael Oppenheimer and Dr. Michael Bolender of the Air Vehicles Directorate, Air Force Research Lab Dayton Ohio. The primary focus of this work is to demonstrate the feasibility of inner loop reconfiguration and outer loop trajectory retargeting and replanning for the X-33 reusable launch vehicle (RLV) following the imposition of a control surface failure. The trajectory generation model employs path constraints generated by an AFRL trim deficiency algorithm coupled with an inner loop control allocator and aerodynamic database that captures the full 6-DOF vehicle aerodynamic effects while utilizing an outer loop 3-DOF model. The resulting optimal trajectory does not violate the trim deficiency constraints and provides additional margins for trajectories flown during failure conditions. The footprints generated by the thesis show that contemporary footprint analysis for vehicles experiencing control surface failures are overly optimistic when compared to those footprints that consider vehicle aerodynamic stability and realistic landable attitudes at the threshold of the landing runway. The results of the thesis also show the performance reductions resulting from decoupling the inner and outer loop and that trajectories can be generated to the landing runway without using a region of terminal area energy management. / Commander, United States Navy
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Optimization-Based Spatial Positioning and Energy Management for Unmanned Aerial VehiclesMartin, Ronald Abraham 01 December 2018 (has links)
This research applies techniques from the field of optimization to spatial positioning and energy management in Unmanned Aerial Vehicles (UAVs). Two specific areas are treated: optimization of UAV view plans for 3D modeling of infrastructure, and trajectory optimization of solar powered high-altitude long-endurance (HALE) UAVs. Structure-from-Motion (SfM) is a computer vision technique for creating 3D models from 2D images. View planning is the process of planning image sets that will effectively model a given scene. First, a genetic algorithm based view planning approach is demonstrated. A novel terrain simulation environment is developed, and the algorithm is tested at multiple sites of interest. The genetic algorithm is compared quantitatively to traditional flights, and is found to yield terrain models with up to 43% greater accuracy than a standard grid flight pattern. Next a greedy heuristic planner is developed, and used to combine anomaly detection with automatic on-board 3D view planning for long linear infrastructure objects such as canals and pipelines. The proposed method is shown in simulation to decrease total flight time by up to 55%, while reducing the amount of image data to be processed by 89% and maintaining 3D model accuracy at areas of interest. The planning algorithm is then extended to select images of ground targets from an existing data set. The algorithm is tested on five different targets, and is shown to reduce processing time for target models by up to a factor of 50 with little decrease in accuracy. The second portion of the research demonstrates the use of nonlinear dynamic optimization to calculate energy optimal trajectories for a high-altitude, solar-powered Unmanned Aerial Vehicle (UAV). The objective is to maximize the total energy in the system while staying within a 3 km mission radius and meeting other system constraints. Solar energy capture is modeled using the vehicle orientation and solar position, and energy is stored both in batteries and in potential energy through elevation gain. Energy capture is maximized by optimally adjusting the angle of the aircraft surface relative to the sun. The UAV flight and energy system dynamics are optimized over a 24-hour period at an eight-second time resolution using Nonlinear Model Predictive Control (NMPC). Results of the simulated flights are presented for all four seasons, showing 8.2% increase in end-of-day battery energy for the most limiting flight condition of the wintersolstice.
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