This thesis constitutes the documentation for a Doctoral research program
undertaken at the Industrial Research Institute of Swinburne University of Technology
(IRIS) between 2001 and 2005. The focus of the research was an investigation of the
open- and closed-loop response of piezoelectric micro-pumps for micro-fluidic
applications, particularly for chemical and biomedical environments. Specifically, in
order to successfully integrate micro-devices into functional systems, it was important
to address issues of real-time performance monitoring and control. The research
addresses some of these problems in the context of a piezoelectric-driven micro-pump,
equipped with interferometric displacement feedback, which was used to measure the
dynamic displacement of the micro-pump actuator surface.
During the course of the research, both a discrete component and a fully integrated
(laboratory-on-a-board) test system were developed for open-loop characterization of
the micro-pump. The laboratory-on-a-board system was also used for closed-loop
control application. Measurements showed significant differences in actuator velocity,
displacement and settling time between different pumping media. In addition, transient
underdamped vibration of the actuator surface was observed during the rapid excursion
and recursion phases of the pump movement while pumping air. These non-contact
measurements could be used to determine the open-loop characteristics of a micropump
and provide information for design improvement or failure detection/analysis.
The technique could also be used to provide continuous measurement for adaptive
compensation, so that the pump performance criteria are always satisfied. To this end,
an automated interference fringe counting algorithm was developed, so that the steadystate
parameters could be mapped into the closed-loop control elements in real time.
The performance of this algorithm is discussed herein, together with the implications for
optimal control of the micro-pump, and eventual integration of the interferometer and
micro-pump systems. The research indicated that there were potential benefits in
closed-loop control of micro-pumps, particularly where failure detection was required
and for pumping of non-homogeneous media. The thesis also documents the relative
performance differences between open and closed-loop control in homogenous media.
| Identifer | oai:union.ndltd.org:ADTP/216622 |
| Date | January 2006 |
| Creators | Tomac, Tom, n/a |
| Publisher | Swinburne University of Technology. |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | http://www.swin.edu.au/), Copyright Tom Tomac |
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