Research On Precision Motion Control Method Of Microfluidic Based On Iterative Learning

Microfluidics technology is a new technology in modern life science research.It mainly refers to the integration of a series of experiments in a chip with a size of a few centimeters to study the characteristics of microfluidics in micron-scale space.Microfluidics technology greatly enhances the advantages of microfluidics in low consumption,automation and high throughput,and is widely used in chemistry,microelectronics,materials science,biology and biomedical engineering.Although microfluidic technology has many advantages,due to the influence of the complex physical characteristics of the fluid itself,as well as the influence of microfluidic chip manufacturing accuracy and non-standard experimental operations,it is very difficult to achieve the precise control of microfluidics.By analyzing the complex dynamic characteristics of the two-phase fluid in the microchannel,this paper studies the control method of microfluidics,and designs an iterative learning controller that is not based on mathematical models,so that the two-phase fluid in the microchannel can move according to the setting way and achieve the effect of high-precision tracking motion control.The thesis studies from four aspects: microfluidic network system modeling,iterative learning controller design,microfluidic chip production and experimental verification.The main contents are as follows:(1)According to the dynamic characteristics of the microfluidic network system,the factors that affect the position of the laminar flow interface and the size of the droplets in the microfluidic channel are studied.Then,the Y-type microfluidic chip,the T-type microfluidic chip and the cross type microfluidic chip are designed and fabricated respectively.(2)Based on the designed Y-type microfluidic chip,a mathematical model of laminar flow in the microchannel is established,and an iterative learning controller that is not based on the precision mathematical model of the laminar flow is designed.The experimental verification is carried out through the built-in laminar flow experimental platform,and the experimental results show that the designed controller can achieve precise control of the laminar flow interface.Then the designed controller is applied in different microfluidic channels,and the simulation analysis is carried out through large-scale simulation software.By simulation,the simulation result also show the effectiveness of the control scheme.(3)Considering the factors that affect the formation of droplets,a mathematical model of droplet size in the T-shaped microchannel is established,and an iterative learning controller is designed to control the size of the droplet.The experiment is carried out through the microdroplet experiment platform,and the experimental results show that the designed controller can achieve precise control of the droplet size in the T-type microfluidic system.(4)The method of generating droplets in the cross-shaped microfluidic channel is studied,and based on the designed cross-shaped microfluidic chip with piezoelectric ceramic vibrator,a microfluidic network system is built.Then the idea of ILC is introduced into the cross-type microfluidic system,and the effectiveness of the designed control scheme is verified through experiments.