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Title:Modeling and control of high density microcantilever systems
Author(s):Mehmet, Berkem
Advisor(s):Voulgaris, Petros G.
Department / Program:Mechanical Sci & Engineering
Discipline:Mechanical Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Multivariable Control
Structured Singular Value
H infinity Control
Distributed Controller
Microcantilever Dynamics
Finite Element Method
Abstract:In this thesis we build on our earlier work on the control of high density, electrostatically actuated microcantilever arrays and present simple state feedback controllers that can achieve reasonable performance. These controllers are localized, spatially distributed and yield tracking performances comparable to the performance of the more complex H infinity controller that takes disturbances and couplings into account, for reference frequencies as high as 3000 rad/sec. These simpler structures come with the cost of worse performance at higher frequencies, relatively inferior robustness to phase shifts and a state availability requirement. Therefore, they can be effectively used for relatively lower bandwidth applications where the states are measurable. The H infinity controller on the other hand operates quite well at higher, spatially varying frequencies despite having a limited output information. This can be first demonstrated by developing a centralized controller for an array consisting of a finite number of cantilevers in order to have a benchmark. Using infinite abstraction methods however a localized and spatially distributed controller on par with the centralized control can be developed for the infinite cantilever array. Instead of regarding only the cantilever tip as if the cantilever was a point mass the above results can be further verified by using a multimodal model of the cantilever system. The FEM model, as a typical multimodal method, views the cantilever as a more complex structure by cutting it into segments and taking the dynamics of each segment into calculation. Hence this methodology yields a more accurate idea about the control of high density microcantilever systems.
Issue Date:2012-05-22
Rights Information:Copyright 2012 Berkem Mehmet
Date Available in IDEALS:2012-05-22
Date Deposited:2012-05

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