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Dynamical formulations and control of an automatic retargeting systemSovinsky, Michael Charles 25 April 2007 (has links)
The Poincare equations, also known as Lagrange's equations in quasi coordinates,
are revisited with special attention focused on a diagonal form. The diagonal
form stems from a special choice of quasi velocities that were first introduced by Georg
Hamel nearly a century ago. The form has been largely ignored because the quasi
velocities create so-called Hamel coefficients that appear in the governing equations
and are based on the partial derivative of the mass matrix factorization. Consequently,
closed-form expressions for the Hamel coefficients can be difficult to obtain
and relying on finite-dimensional, numerical methods are unattractive. In this thesis
we use a newly developed operator overloading technique to automatically generate
the Hamel coefficients through exact partial differentiation together with numerical
evaluation. The equations can then be numerically integrated for system simulation.
These special Poincare equations are called the Hamel Form and their usefulness in
dynamic modeling and control is investigated.
Coordinated control algorithms for an automatic retargeting system are developed
in an attempt to protect an area against direct assaults. The scenario is for
a few weapon systems to suddenly be faced with many hostile targets appearing together.
The weapon systems must decide which weapon system will attack which
target and in whatever order deemed sufficient to defend the protected area. This
must be performed in a real-time environment, where every second is crucial. Four different control methods in this thesis are developed. They are tested against each
other in computer simulations to determine the survivability and thought process of
the control algorithms. An auction based control algorithm finding targets of opportunity
achieved the best results.
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New methods for estimation, modeling and validation of dynamical systems using automatic differentiationGriffith, Daniel Todd 17 February 2005 (has links)
The main objective of this work is to demonstrate some new computational methods
for estimation, optimization and modeling of dynamical systems that use automatic
differentiation. Particular focus will be upon dynamical systems arising in Aerospace
Engineering. Automatic differentiation is a recursive computational algorithm, which
enables computation of analytically rigorous partial derivatives of any user-specified
function. All associated computations occur, in the background without user
intervention, as the name implies. The computational methods of this dissertation are
enabled by a new automatic differentiation tool, OCEA (Object oriented Coordinate
Embedding Method). OCEA has been recently developed and makes possible efficient
computation and evaluation of partial derivatives with minimal user coding. The key
results in this dissertation details the use of OCEA through a number of computational
studies in estimation and dynamical modeling.
Several prototype problems are studied in order to evaluate judicious ways to use
OCEA. Additionally, new solution methods are introduced in order to ascertain the
extended capability of this new computational tool. Computational tradeoffs are studied
in detail by looking at a number of different applications in the areas of estimation,
dynamical system modeling, and validation of solution accuracy for complex dynamical
systems. The results of these computational studies provide new insights and indicate
the future potential of OCEA in its further development.
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