Date of Award

8-2016

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Mechanical Engineering

Committee Member

Ethan Kung, PhD, Committee Chair

Committee Member

Richard Figliola, PhD

Committee Member

Georges Fadel, PhD

Abstract

Benchtop In-vitro experiments are valuable tools for investigating the cardiovascular system and testing medical devices. Accurate reproduction of physiologic flow waveforms at various anatomic locations is an important component of these experimental methods. This study discusses the design, construction and testing of a low-cost and fully programmable pulsatile flow pump capable of continuously producing unlimited cycles of physiologic waveforms. Two prototypes with different designs were tested. The first one consisted of a stepper motor – piston pump combination and tests showed that it failed to satisfy the design requirements. The second, highly successful prototype consists of a gear pump actuated by an AC servo-motor and a feedback algorithm enabling high accuracy for flow rates up to 300ml/s across a range of loading conditions. The iterative feedback algorithm uses flow error values in one iteration to modify motor control waveform for the next iteration to better match desired flow. Within 4-7 iterations of feedback, the pump replicated physiologic flow waveforms to high levels of accuracy (normalized RMS error less than 2%) under varying downstream impedances. This device is significantly more affordable (~10% of the cost) than current commercial options. Furthermore, the pump can be controlled via common scientific software packages and thus can be implemented in large automation frameworks.

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