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Full-Text Articles in Engineering
Efficient Tether Dynamic Model Formulation Using Recursive Rigid-Body Dynamics, Brad Hembree, Nathan Slegers
Efficient Tether Dynamic Model Formulation Using Recursive Rigid-Body Dynamics, Brad Hembree, Nathan Slegers
Faculty Publications - Biomedical, Mechanical, and Civil Engineering
A computationally efficient discrete model for low-strain tethers used in many engineering applications is developed without the use of elastic elements. The tether is modelled using N links, with each link treated as a body of revolution where it is assumed the tether spin is negligible to the dynamics, resulting in each link having only two degrees of freedom. A recursive algorithm is developed for the dynamic equations, with the solution procedure being an order N method requiring only a 2 x 2 matrix inversion, resulting in approximately half the computations of the general recursive algorithm. A comparison between the …
Effects Of Canopy-Payload Relative Motion On Control Of Autonomous Parafoils, Nathan Slegers
Effects Of Canopy-Payload Relative Motion On Control Of Autonomous Parafoils, Nathan Slegers
Faculty Publications - Biomedical, Mechanical, and Civil Engineering
An 8 degree-of-freedom model is developed that accurately models relative pitching and yawing motion of a payload with respect to a parafoil. Constraint forces and moments are found analytically rather than using artificial constraint stabilization. A turn rate controller common in precision placement algorithms is used to demonstrate that relative yawing motion of the payload can result in persistent oscillations of the system. A model neglecting relative payload yawing failed to predict the same oscillations. It is shown that persistent oscillations can be eliminated by reduction of feedback gains; however, resulting tracking performance is poor. A reduced order linear model …