Control for Carbon Dioxide Exchange Process in a Membrane Oxygenator Using Online Self-Tuning Fuzzy-PID Controller

•Comprehensive literature review about membrane oxygenator in extracorporeal life support and treatment for lung diseases,•Comprehensive mathematical modelling of membrane oxygenator system for extracorporeal life support,•Design of Fuzzy PID controller for controlling the CO2 exchange process in a membrane oxygenator system,•Performance comparison between proposed Fuzzy PID and conventional controllers to achieve the control objective.•Simulations as for the preparation work for experimental investigation in control application for membrane oxygenator in extracorporeal life support. The aim of this study is to evaluate the performance of conventional PID that is tuned using Zeigler-Nichols continuous cycling, Fuzzy Logic Controller (FLC) and self-tuning Fuzzy-PID (self-tuning FPID) methods to control the rate of CO2 removal from a membrane oxygenator during extracorporeal blood purification process. Sweep gas flow rate is chosen as the manipulated variable of arterial CO2 partial pressure (pCO2) in blood. The performance of these controllers is evaluated based on their response in controlling task and also by the calculation of three performance indices, namely Integral Absolute Error (IAE), Integral Squared Error (ISE) and Integral Time Absolute Error (ITAE). The robustness of the controllers using these tuning methods is then assessed for set point tracking and load disturbance rejection tests. Results indicated that the self-tuning FPID is observed as the best controller compared to conventional PID and FLC with lower oscillation, overshoot and shorter settling time. As for quantitative measurement, self-tuning FPID outshines the other controllers with 0.854, 1.084 and 41.450 for IAE, ISE and ITAE, respectively in set point tracking task while 0.532 IAE, 0.016 ISE and 28.970 ITAE measured for load disturbance rejections. It can be concluded that self-tuning FPID is the best controller to be used in the automation of extracorporeal circulation control for both set point tracking and load disturbance rejection tests.