A microfluidic system with fuzzy PID controller

In this work, a novel micoropump actuated by EO (electroosmotic) actuators toward biomedical systems and drug delivery systems. The classical structure, which consists of an actuating unit, chambers and rectifiers, has been employed in the design. The EO actuators with the impulse input make the polydimethylsiloxane (PDMS) diaphragm which separates the two chambers reciprocate. So the working liquid can be pumped from inlet to outlet. Due to the large deflections of the PDMS diaphragm, the device is completely self-filling and able to pump liquid even operated in vertical situation. By using the indirect pumping mechanisms, the EO actuator can be used more widely without considering the properties of the working liquid. And a maximum flow rate of 133μl/min (using top water as working liquid) was obtained by an input voltage of 30V and an exciting frequency of 1.4Hz. In order to get a stable flow rate, a fuzzy PID control approach has been adopted in the controlling system. And some experiments were manipulated to show the characteristics of the PDMS diaphragm and the check valve. These experiments results demonstrate the diaphragm micropump performance and ability to deliver the fluid and drugs to biomedical systems.