Control, Modeling and Evaluation of a Magnetic Piston Miniature Pump

Abstract

This paper presents the control design and performance evaluation of a novel meso-scale electromechanical fluid pump. Such pumps have the potential for applications in biomedical, chemical and pharmaceutical engineering fields. The pumping concept is based on reciprocating a hard magnet working as a double-acting piston in a circular channel, and synchronizing this movement with two electromagnetically actuated valves located at the pump inlet and outlet ports. The actuation system is programmed to allow sequential energization of a set of coils that control the magnet positions. Each pump port has an inlet and outlet channel. According to the piston movement direction, i.e. clockwise or counter clockwise, the valve magnets will change their positions to allow for inflow or outflow. The pump concept was tested using three control configurations, where piston stroke length, stroke frequency, and energization schemes were varied. Calculations showed that the second configuration has the highest volumetric efficiency of about 90% and the maximum flow rate of 8 mL/min at 78 piston strokes per minute (spm). The maximum pressure was achieved using the third configuration with about 575 Pa at 70 spm.