NONLINEAR CONTROLLER COMPARISON ON A BENCHMARK ...

NONLINEAR CONTROLLER COMPARISON ON A BENCHMARK ... NONLINEAR CONTROLLER COMPARISON ON A BENCHMARK ...

24.08.2013 Views

BRIGHAM YOUNG UNIVERSITY As chair of the candidate's graduate committee, I have read the thesis of J. Willard Curtis III in its nal form and have found that (1) its format, citations, and bibliographical style are consistent and acceptable and ful ll university and department style requirements (2) its illustrative materials including gures, tables, and charts are in place and (3) the nal manuscript is satisfactory to the graduate committee and is ready for submission to the university library. Date Randy W. Beard Chair, Graduate Committee Accepted for the Department Accepted for the College A. Lee Swindlehurst Graduate Coordinator Douglas M. Chabries Dean, College of Engineering and Technology

ABSTRACT NONLINEAR CONTROLLER COMPARISON ON A BENCHMARK SYSTEM J. Willard Curtis III Department ofElectrical and Computer Engineering Master of Science The quest for practical, robust, and e ective nonlinear feedback controllers has been an area of active research in recent years. One of the challenges in this research ishowtoevaluate the performance of new nonlinear control strategies, given that the set of nonlinear systems is so varied. A benchmark problem for nonlinear systems has been proposed, in order to provide a standard testbed for newly devel- oped, nonlinear control algorithms. This benchmark problem is an ideal system on which to apply the Successive Galerkin Approximation to the optimal nonlinear full- state feedback problem. The Successive Galerkin Approximation (SGA) technique provides an approximation to the solution of the Hamilton-Jacobi equations associ- ated with optimal nonlinear control theory. The main contribution of this thesis is the comparison of the SGA algorithm to four other control methodologies, each of which is implemented on a hardware system that can be modeled as the nonlinear benchmark problem. The results show that the SGA algorithms provide excellent performance and good robustness properties when applied to this benchmark system, outperforming a simple passivity-based control, two standard linearized controls, and a simpli ed backstepping control.

ABSTRACT<br />

<strong>N<strong>ON</strong>LINEAR</strong> <strong>C<strong>ON</strong>TROLLER</strong> <strong>COMPARIS<strong>ON</strong></strong> <strong>ON</strong> A <strong>BENCHMARK</strong> SYSTEM<br />

J. Willard Curtis III<br />

Department ofElectrical and Computer Engineering<br />

Master of Science<br />

The quest for practical, robust, and e ective nonlinear feedback controllers<br />

has been an area of active research in recent years. One of the challenges in this<br />

research ishowtoevaluate the performance of new nonlinear control strategies, given<br />

that the set of nonlinear systems is so varied. A benchmark problem for nonlinear<br />

systems has been proposed, in order to provide a standard testbed for newly devel-<br />

oped, nonlinear control algorithms. This benchmark problem is an ideal system on<br />

which to apply the Successive Galerkin Approximation to the optimal nonlinear full-<br />

state feedback problem. The Successive Galerkin Approximation (SGA) technique<br />

provides an approximation to the solution of the Hamilton-Jacobi equations associ-<br />

ated with optimal nonlinear control theory. The main contribution of this thesis is<br />

the comparison of the SGA algorithm to four other control methodologies, each of<br />

which is implemented on a hardware system that can be modeled as the nonlinear<br />

benchmark problem. The results show that the SGA algorithms provide excellent<br />

performance and good robustness properties when applied to this benchmark system,<br />

outperforming a simple passivity-based control, two standard linearized controls, and<br />

a simpli ed backstepping control.

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