Tag Archives: Proportional-Integral-Derivative (PID) controller

Making lab-on-a-chip devices more accurate

An April 4, 2016 news item on phys.org announces research that will improve control and manipulation of the fluids in a lab-on-a-chip,

Lab-on-a-chip designates devices that integrate various biochemical functions on a fingernail-sized chip to enable quick and compact biological analysis or medical diagnosis by processing a small volume of biological samples, such as a drop of blood. To operate various functions on a lab-on-a-chip device, the key technology is the precise and rapid manipulation of fluid on a micro-scale.

A March 31, 2016 Pohang University of Science and Technology (POSTECH; South Korea) press release (also on EurekAlert), which originated the news item, expands on the theme,

In microfluidic devices, very small and trivial variables can frequently cause a large amount of errors. Up until now, Proportional-Integral-Derivative (PID) controller has normally been used for the manipulation of fluids in microfluidic chips. To apply the PID controller, a tedious gain-tuning process is required but the gain-tuning is a difficult process for people who are unfamiliar with control theory. Especially, in the case of controlling multiple flows, the process is extremely convoluted and frustrating.

The developed control algorithm can improve accuracy and stability of flow regulation in a microfluidic network without requiring any tuning process. With this algorithm, microfluidic flows in multiple channels can be controlled in simultaneous and independent way. The team expects that this algorithm has the potential for many applications of lab-on-a-chip devices. For example, cell culture or biological analysis, which are conducted in biology laboratories, can be performed on a microfluidic chip. Physical and chemical responses can be analyzed in the subdivided levels.

Here’s a link to and a citation for the paper,

Tuning-free controller to accurately regulate flow rates in a microfluidic network by Young Jin Heo, Junsu Kang, Min Jun Kim, & Wan Kyun Chung. Scientific Reports 6, Article number: 23273 (2016) doi:10.1038/srep23273 Published online: 18 March 2016

This is an open access paper.