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Full-Text Articles in Navigation, Guidance, Control and Dynamics
Analytic Guidance Strategies For Passively Safe Rendezvous And Proximity Operations, Simon Shuster
Analytic Guidance Strategies For Passively Safe Rendezvous And Proximity Operations, Simon Shuster
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
A safety ellipse is a type of relative motion trajectory that is commonly used for unmanned rendezvous and proximity operations. As the name suggests, safety ellipses are passively safe relative motion trajectories, which means that their natural motion inherently maintains a low collision risk. The focus of this dissertation is the derivation, analysis, and application of guidance strategies that reconfigure, establish, and exit a safety ellipse. The guidance strategies consist of a set of ∆v vectors and impulse times, all written in closed form. Through applications of optimal control theory and parameter optimization, it is shown that these maneuver …
Investigation Of Factors Impacting A Helicopter Height-Velocity Diagram, Timothy A. Brown
Investigation Of Factors Impacting A Helicopter Height-Velocity Diagram, Timothy A. Brown
Theses and Dissertations
A dynamic helicopter model was incorporated into an optimal control problem to determine minimal landing velocities. The solutions were determined using pseudospectral collocation methods as implemented by the GPOPS-II software. These solutions were then compiled to develop a HV diagram. An HV diagram displays regions of flight based on a helicopter's airspeed and height above the ground in which a safe landing would not be possible following engine failure. The applied methodology for constructing the HV diagram reduced issues involving solution convergence that was encountered in previous research. The influence of ground effect on the dynamic model was also investigated. …