Date of Award

5-2012

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Electrical Engineering

Advisor

Groff, Richard E

Committee Member

Kornev , Konstantine G

Committee Member

Dawson , Darren M

Abstract

Polymer fibers of varying microfluidic properties can be fabricated in a lab setting. Fibers coated with paramagnetic particles act like slender paramagnetic beams. These fiber moves in a magnetic field. Thus polymer fibers coated with paramagnetic particles can be used as actuators in various microfluidic applications, such as DNA separation, droplet manipulation and liquid transport. In order to use the fibers as actuators, it is necessary to model the fiber and develop control strategies.
A static model of the paramagnetic fiber based on energy methods is presented in [1]. The model relies on a demagnetizing factors approximation to determine the magnetic field inside the fiber. The first part of the thesis examines the conditions under which the demagnetizing factors approximation holds.
The model allows for implementation of simple feedforward control strategies to control the position of the fiber. For implementation of better control algorithms, methods to sense the shape and the tip position of the fiber are required. These sensing methods are also presented here.
The model depends on the bending rigidity and magnetic susceptibility of the fiber. Since the fibers can be synthesized in a lab setting, these properties are usually not known. This thesis also presents methods to characterize the bending rigidity of the fiber, based on the sensing methods.
The bending rigidity and the magnetic susceptibility of the fiber, along with the model can be used to implement a basic feedforward control strategy to accurately position the tip of the fiber. This enables the use of the fiber as a microfluidic actuator.

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