Modeling and control of high density microcantilever systems

Mehmet, Berkem

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https://hdl.handle.net/2142/30892 Copy

Description

Title

Modeling and control of high density microcantilever systems

Author(s)

Mehmet, Berkem

Issue Date

2012-05-22T00:13:38Z

Director of Research (if dissertation) or Advisor (if thesis)

Voulgaris, Petros G.

Department of Study

Mechanical Sci & Engineering

Discipline

Mechanical Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(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.

Graduation Semester

2012-05

Permalink

http://hdl.handle.net/2142/30892

Copyright and License Information

Copyright 2012 Berkem Mehmet

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