Optimization of symmetric output feedback control for large flexible structures /
| Main Author: | |
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1990.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | The primary objective of this study is to develop a new methodology to optimize globally stable output feedback controllers for mechanical second-order systems. In the first part of this dissertation, a new measure of controllability for linear time invariant dynamical system is developed. Qualitatively, this new measure represents a measure of "output controllability" which reflects both modal controllability and the modal participation of all modes in the physically important cost function. This controllability measure is designed especially to guide the placement of actuators to control vibrating structures. In addition, optimization methods to find optimum actuator configurations are addressed. In the second part of this dissertation, a new methodology to optimize globally stable output feedback controllers for mechanical second-order systems is developed. For theoretical background, a few analytical issues involved in symmetric output feedback controller design are discussed, including stability analysis, stability robustness analysis, and a relationship to LQR design. To optimize over a stable family of gains, a homotopy-based nonlinear programming method is introduced which sweeps through a sequence of nearest neighbor designs to impose inequality constraints on the closed-Ioop eigenvalues. To enhance robustness, the condition number of the closed-loop modal matrix is minimized. Finally, to support the practical value of the ideas presented in this study, we consider numerical examples in two sets: i) using a twenty one degree-of-freedom model of a planar rotational/vibrational flexible structure consisting of a rigid hub with four cantilevered flexible appendages and ii) using a sixty degree-of-freedom model of a grid structure. The proposed symmetric output feedback design method is successfully implemented and tested for both sets of examples. Evidence supporting the usefulness of the proposed new index is also presented, based upon comparing the numerical results of two control design methods (symmetric output feedback controller and linear quadratic regulator) for a grid structure with ten different actuator configurations. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Aerospace engineering." |
| Physical Description: | x, 146 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |