Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 57 for “"Optimal trajectories"”.
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Optimal trajectories for hypervelocity flight
This thesis discusses optimal trajectories for hypervelocity flight of interest in aeroassisted orbital transfer. Both coplanar orbital transfer and noncoplanar orbital transfer are studied. For these cases, the GEO-to-LEO transfer, the HEO-to-LEO transfer, and the LEO-to-LEO transfer are …
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Optimal trajectories for maneuvering reentry vehicles
… maneuverable re-entry vehicles that can fly trajectories that have stringent path and terminal constraints, including those that cannot be written as drag or energy constraints. This work presents a method based on trajectory optimization techniques to assess the capabilities of the re-entry …
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Optimal trajectories for fast quantum harmonic transport
… an easily-computed functional of transport trajectories with intuitively interpretable terms which may be used to compare solutions to the quantum harmonic transport problem, but does not require an expensive quantum-mechanical simulation of the ion dynamics. Furthermore, we prove the …
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Optimal trajectories and orbit design for separated spacecraft interferrometry
… from such a system, this study addresses the optimal trajectories for a SSI operating both outside and within a gravity-well. In the case of imaging from outside the gravity-well, the sequence of physical locations, where measurements are made to best mimic the point spread function of an …
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Six degree of freedom optimal trajectories for satellite rendezvous
… of the impact that these parameters have on the optimal solutions for two different models of the satellite thruster systems is then presented.
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Applications of Second-Order Necessary and Sufficient Conditions to Optimal Trajectories
… conditions for a weak local minimum in optimal control problems is used to develop a procedure for applying second-order necessary and sufficient conditions for a minimum of a cost functional. For a system with n state variables, an improved Riccati equation solution method is used to …
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Optimal and on-board near-optimal midcourse guidance
Optimal midcourse guidance is examined for an air-to-air missile featuring boost-coast-sustain propulsion. A vertical plane, point-mass model is studied with load factor as a control variable. Time-range-energy optimal trajectories are computed, open-loop, via the usual necessary conditions and a …
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Models, optimal performances and sensitivities of commercial flight trajectory in the air traffic system
… concepts to evaluate the qualities of generated optimal trajectories. The trajectory generation is typically performed by individual aircraft or their airline operation centers to optimize flight performances including flight time or flight distance. Additionally, while aircraft environmental …
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Dynamic economic dispatch of power systems by multi-pass dynamic programming
… Dispatch problem together to form a dynamic optimal control problem. A power system was partitioned into the Electric Power Network subsystem and the Mechanical Power Control subsystem. Earlier work has solved the Electric Network subsystem control problem, used analytical methods to find …
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Fuel optimal rendezvous including a radial constraint
Fuel-optimal rendezvous in orbit is examined using thrust-impulses and coasting arcs. Necessary conditions for the optimality of fuel-optimal rendezvous with and without radial constraints are derived. These conditions are then used to verify the optimality of trajectories obtained from a …
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Efficient Trajectory Optimization Procedure for Designing Solar -Electric Propulsion, Gravity -Assist Outer -Planet Missions
… the performance of different revolution ratio trajectories from a set of optimal trajectories using a linear least square fitting method. This technique brings further understanding of the effect of different revolution ratio outer-planet missions. It also provides performance prediction …
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Modeling and Control of Transient Enhanced Diffusion of Boron in Silicon
… optimization is formulated to design the optimal annealing temperature program that gives the minimum junction depth while maintaining satisfactory sheet resistance. Comparison of different parameterizations of the optimal trajectories shows that linear profiles give the best combination …
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Aircraft cruise performance optimization using chattering controls
… energy-state modelling to investigate fuel-range optimal trajectories. Chattering controls are considered appropriate when the hodograph is non-convex. Classical steady-state cruise, simple chattering-cruise and the extended chattering-cruise models are studied as constrained …
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Lossless convexification of quadrotor motion planning with experiments
… position constraints. Using the convexied optimal trajectory generation problem with physical and path constraints, an algorithm is developed that generates fuel optimal trajectories given the initial state and desired final state. As a proof of concept, a quadrotor testbed is developed …
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Trajectory optimization for a fixed trim re-entry vehicle using direct collocation with nonlinear programming
A procedure is developed to calculate locally optimal trajectories for a class of fixed-trim atmospheric re-entry vehicles. A four degree-of-freedom vehicle model is introduced and appropriate environmental models are chosen and implemented. Software is developed to discretize the optimal control …
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Optimal rigid-body rotational maneuvers
Optimal rigid-body angular maneuvers are investigated, using restricted control moments—a problem inspired in the context of rotational maneuvers for <i>super-maneuverable</i> aircraft. Most of the analysis is based on the formulation with no direct control over the roll component of angular …
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Spacecraft Trajectory Optimization Suite (STOpS): Optimization of Multiple Gravity Assist Spacecraft Trajectories Using Modern Optimization Techniques
… programs have been developed to analyze MGA trajectories. One of these programs, Parallel Global Multiobjective Optimization (PaGMO), uses an interesting technique known as the Island Model Paradigm. This work provides the community with a MATLAB optimizer, STOpS, that utilizes this same …
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Feasibility Analysis and Fuel Burn Benefits of Relaxing Constraints in High Altitude Cruise
… such as enabling more fuel-efficient trajectories, are desirable in mitigating the environmental impact of air travel due to their relatively fast implementation potential. In particular, the vertical inefficiency arising from the altitude stratification in the airspace can be …
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Trajectory design and control for formation flying spaceborne interferometers
… The purpose of this study is to investigate optimal resource management techniques for separated space-craft interferometers to successfully synthesize images. Assuming optimal imaging configurations that satisfy astronomical requirements have been selected, a two-step approach is taken to …
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