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Full-Text Articles in Engineering
Terminal Guidance Of Autonomous Parafoils In High Wind-To-Airspeed Ratios, Nathan Slegers, O A. Yakimenko
Terminal Guidance Of Autonomous Parafoils In High Wind-To-Airspeed Ratios, Nathan Slegers, O A. Yakimenko
Faculty Publications - Biomedical, Mechanical, and Civil Engineering
Autonomous precision placement of parafoils is challenging because of their limited control authority and sensitivity to winds. In particular, when wind speed is near the airspeed, guidance is further complicated by the parafoils inability to penetrate the wind. This article specifically addresses the terminal phase and develops an approach for generating optimal trajectories in real-time based on the inverse dynamics in the virtual domain. The method results in efficient solution of a two-point boundary-value problem using only a single optimization parameter allowing the trajectory to be generated at a high rate, mitigating effects of the unknown winds. It is shown …
Tethered Aerostat Modeling Using An Efficient Recursive Rigid-Body Dynamics Approach, Brad Hembree, Nathan Slegers
Tethered Aerostat Modeling Using An Efficient Recursive Rigid-Body Dynamics Approach, Brad Hembree, Nathan Slegers
Faculty Publications - Biomedical, Mechanical, and Civil Engineering
A tethered aerostat model is developed using a computationally efficient recursive tether model. The recursive rigid-body tether model results in unconstrained ordinary differential equations and maintains much of the simplicity of simple lumped-mass tether models, while avoiding numerical difficulties associated with using many stiff elastic elements with low mass. Further efficiency is achieved by treating each tether link as a body of revolution and assuming that tether spin is negligible to the dynamics. The tether is attached to a six-degree-of-freedom aerostat model using a single viscoelastic element. The final recursive tethered aerostat model is well suited for a variety of …