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Navigation, Guidance, Control and Dynamics Commons

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2010

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Articles 31 - 33 of 33

Full-Text Articles in Navigation, Guidance, Control and Dynamics

Efficient Tether Dynamic Model Formulation Using Recursive Rigid-Body Dynamics, Brad Hembree, Nathan Slegers Jan 2010

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 Jan 2010

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 …


Fusion Of Imprecise Qualitative Information, Florentin Smarandache, Xinde Li, Xianzhong Dai, Jean Dezert Jan 2010

Fusion Of Imprecise Qualitative Information, Florentin Smarandache, Xinde Li, Xianzhong Dai, Jean Dezert

Branch Mathematics and Statistics Faculty and Staff Publications

In this paper, we present a new 2-tuple linguistic representation model, i.e. Distribution Function Model (DFM), for combining imprecise qualitative information using fusion rules drawn from Dezert-Smarandache Theory (DSmT) framework. Such new approach allows to preserve the precision and efficiency of the combination of linguistic information in the case of either equidistant or unbalanced label model. Some basic operators on imprecise 2-tuple labels are presented together with their extensions for imprecise 2-tuple labels. We also give simple examples to show how precise and imprecise qualitative information can be combined for reasoning under uncertainty. It is concluded that DSmT can deal …