PID controller design to generate pulsatile flow rate for in vitro experimental studies of physiological flows
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Producing accurate pulsatile flow rates is essential for many in vitro experimental studies in biofluid dynamics research. A controller system was developed to control a flow loop to produce easily adjustable pulsatile flow rates with sufficient accuracy. An Arduino board is used as a micro-controller to control a pump to produce various pulsatile flow rates, and an open-source proportional-integral-derivative (PID) control algorithm is developed for this purpose. Four non-trivial pulsatile waveforms were produced by the PID controller, as well as an iterative controller, and the performance of both controllers was evaluated. Both the PID and iterative controllers were able to successfully produce slowly-varying signals (single and multi-harmonic low frequency sine waves), but for high frequency signals where the flow has strong acceleration/deceleration (e.g. for physiological waveforms) the iterative controller exhibited significant undershoot. The comparison of PID and iterative controllers suggests that if the desired flow rate is a low frequency, simple waveform then the iterative controller is preferred due to simplicity of implementation. However, if the desired signal is rapidly changing and more complicated then the PID controller achieves better results. This system can be implemented in many flow loops due to its simplicity and low cost, and does not require a mathematical model of the system.
KeywordsFeedback PID controller Arduino Artery blood flow Common carotid artery Gear pump
This study was supported by the George Washington University Center for Biomimetics and Bioinspired Engineering. The authors would also like to thank Mahdis Bisheban and Kanishke Gamagedara for their contributions.
Compliance with ethical standards
Conflict of interest
All the authors declare that they have no conflict of interest in relation to the work in this article.
This study meets ethical standards for engineering studies at the George Washington University. No humans or animals were involved in this study, thus no ethical or IRB review is required.
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