Capacitance-Based Droplet Position Sensing Optimization Through Digital Microfluidic Parameters

2011 ◽  
Author(s):  
Miguel Angel Murran ◽  
Abbas S. Milani ◽  
Homayoun Najjaran
Keyword(s):  
Empirical Model ◽  
Closed Loop ◽  
Position Control ◽  
Microfluidic Devices ◽  
Position Error ◽  
Droplet Radius ◽  
Dielectric Thickness ◽  
Position Sensing ◽  
Electrode Pitch ◽  
Digital Microfluidic

Design of a closed-loop droplet position control is an essential step towards the development of fully automated digital microfluidic devices. However, the performance of any closed-loop controller is ultimately limited by the accuracy and precision of the feedback sensors. In this paper, an effective capacitance based droplet sensor was designed and optimized through simulation to reduce the droplet position error. A full factorial design was conducted on the droplet sensor simulation model to observe the behavior of the position error as a function of the parameters of a digital microfluidic device. An empirical model was then fitted to the data obtained from the designed simulations and optimized to reduce the position estimate error. Results suggest that the performance of the capacitance based droplet sensor studied in this work is most dependent on the dielectric thickness, droplet radius, electrode pitch, electrode separation, filler fluid permittivity, and plate gap. Isoperformance curves of the sensor performance were obtained using the empirical model to show the interaction between digital microfluidic parameters, as well as to aid in the design of digital microfluidic devices equipped with a similar capacitance based droplet sensor.

Pulse Width Control for Precise Positioning of Structurally Flexible Systems Subject to Stiction and Coulomb Friction

2004 ◽  
Vol 126 (1) ◽  
pp. 131-138 ◽  
Author(s):  
David B. Rathbun ◽  
Martin C. Berg ◽  
Keith W. Buffinton
Keyword(s):  
Limit Cycle ◽  
Pulse Width ◽  
Coulomb Friction ◽  
Closed Loop ◽  
Position Control ◽  
Industrial Robot ◽  
Sufficient Conditions ◽  
Position Error ◽  
Mass System ◽  
Precise Positioning

Pulse width control refers to the use of a control law to determine the duration of fixed-height force pulses for point-to-point position control of a plant that is subject to mechanical friction, including stiction. The use of constant-gain pulse width control laws for precise positioning of structurally flexible plants subject to stiction and Coulomb friction is analyzed. It is shown that when the plant is a simple two-mass system subject to stiction and Coulomb friction, a position error limit cycle can result. Sufficient conditions for stability and self-sustained oscillation of this closed-loop system are derived. The sufficient conditions for stability are used to determine conditions on the plant parameters and the control gain that guarantee closed-loop stability and thus limit-cycle-free operation and zero steady-state position error. The analysis methods that are introduced are demonstrated in applications to the control of the position of the end-effector of an industrial robot.

Method for Individual Control of Multiplexed Droplet Generation in Digital Microfluidic Devices

2013 ◽  
Author(s):  
Michael J. Schertzer ◽  
Zhifang Yang ◽  
Ridha Ben-Mrad ◽  
Pierre E. Sullivan
Keyword(s):  
Closed Loop ◽  
Microfluidic Devices ◽  
Constrained Systems ◽  
Droplet Generation ◽  
Control Algorithms ◽  
Closed Loop Control ◽  
Loop Control ◽  
Digital Microfluidic ◽  
Droplet Control ◽  
Activation Sequence

This investigation presents two methods for multiplexed droplet generation in digital microfluidic devices. Analytical and experimental results show that the number of electrical output signals required for multiple reagent systems can be reduced by electrically connecting all but one electrode in each droplet generation path on the device. Both methods reduce the number of electrical signals required for generating droplets from multiple reservoirs by M(N−1), where M is the number of manipulation electrodes in the generation path and N is the number of reservoirs on the device. The first method uses individually controlled reservoirs to minimize the manipulation of the fluid in the unused reservoir, while the second method individually controls one of the electrodes in the generation pathway to allow for closed loop control of droplet generation. In both cases, droplets are kept at rest by simultaneously activating or deactivating all adjacent electrodes. These methods can be easily integrated into devices with multiple reservoirs without computational expense or prior knowledge of the electrode activation sequence. They can also be used in concert with droplet control algorithms for pin constrained systems to further reduce the number of output channels required in a digital microfluidic device.

scholarly journals Split and flow: reconfigurable capillary connection for digital microfluidic devices

Lab on a Chip ◽  
2014 ◽  
Vol 14 (18) ◽  
pp. 3589-3593 ◽  
Author(s):  
Florian Lapierre ◽  
Maxime Harnois ◽  
Yannick Coffinier ◽  
Rabah Boukherroub ◽  
Vincent Thomy
Keyword(s):  
Microfluidic Devices ◽  
Microfluidic Systems ◽  
Digital Microfluidic

How to take advantage of superhydrophobic microgrids to address the problem of coupling continuous to digital microfluidic systems? A reconfigurable capillary connection for digital microfluidic devices is presented.

scholarly journals Numerical modeling of electrowetting processes in digital microfluidic devices

2010 ◽  
Vol 39 (9) ◽  
pp. 1510-1515 ◽  
Author(s):  
Liviu Clime ◽  
Daniel Brassard ◽  
Teodor Veres
Keyword(s):  
Numerical Modeling ◽  
Microfluidic Devices ◽  
Digital Microfluidic

Design of Salt In-Bags Incasing Control Management System Based on Dual Closed-Loop Fuzzy Controller

2014 ◽  
Vol 596 ◽  
pp. 620-624
Author(s):  
Yan Bo Hui ◽  
Yong Gang Wang ◽  
Li Wang ◽  
Qun Feng Niu
Keyword(s):  
Management System ◽  
Closed Loop ◽  
Position Control ◽  
Product Information ◽  
Fuzzy Controller ◽  
High Reliability ◽  
Logistics Management ◽  
High Control ◽  
Control Management System ◽  
Control Management

According to auto-incasing equipment characteristic and control demand, a kind of salt in-bags incasing control management system was designed. The paper introduced the key technologies realization of the system. In the paper, a new fuzzy controller was designed to build a dual closed-loop fuzzy control system, realizing incasing goal site error on-line continuous correction. A logistics management module based on e-Tag was designed to realize product information traceable management. The experimental results show the system realizes accurate position control and RFID logistics management with high reliability and high control precision. The system can be popularized to other products packaging industry.

Fibre-optic sensing in digital microfluidic devices

2018 ◽  
Vol 280 ◽  
pp. 164-169 ◽  
Author(s):  
Isaac Spotts ◽  
Dima Ismail ◽  
Noor Jaffar ◽  
Christopher M. Collier
Keyword(s):  
Microfluidic Devices ◽  
Fibre Optic ◽  
Digital Microfluidic

scholarly journals Programmable Paper-Based Microfluidic Devices for Biomarker Detections

Micromachines ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 516 ◽  
Author(s):  
Veasna Soum ◽  
Sooyong Park ◽  
Albertus Ivan Brilian ◽  
Oh-Sun Kwon ◽  
Kwanwoo Shin
Keyword(s):  
Point Of Care ◽  
High Sensitivity ◽  
Microfluidic Devices ◽  
Portable Devices ◽  
Biomarker Detection ◽  
Fluid Delivery ◽  
Wide Range ◽  
Paper Based Microfluidics ◽  
Digital Microfluidic ◽  
Detection Of Biomarkers

Recent advanced paper-based microfluidic devices provide an alternative technology for the detection of biomarkers by using affordable and portable devices for point-of-care testing (POCT). Programmable paper-based microfluidic devices enable a wide range of biomarker detection with high sensitivity and automation for single- and multi-step assays because they provide better control for manipulating fluid samples. In this review, we examine the advances in programmable microfluidics, i.e., paper-based continuous-flow microfluidic (p-CMF) devices and paper-based digital microfluidic (p-DMF) devices, for biomarker detection. First, we discuss the methods used to fabricate these two types of paper-based microfluidic devices and the strategies for programming fluid delivery and for droplet manipulation. Next, we discuss the use of these programmable paper-based devices for the single- and multi-step detection of biomarkers. Finally, we present the current limitations of paper-based microfluidics for biomarker detection and the outlook for their development.

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