Comparative Assessment of Fuzzy Logic and PI Controllers for Ratio Control in Liquid Flow System

• Published in: 2024 IEEE 15TH CONTROL AND SYSTEM GRADUATE RESEARCH COLLOQUIUM, ICSGRC 2024
• Main Authors: Abdullah, Nurul Fazlika Syahira; Abdullah, Zalizawati; Kasmuri, Nor Hazelah; Subari, Fuzieah; Hanipah, Suhaiza Hanim
• Format: Proceedings Paper
• Language: English
• Published: IEEE 2024
• Subjects: Automation & Control Systems; Engineering
• Online Access: https://www-webofscience-com.uitm.idm.oclc.org/wos/woscc/full-record/WOS:001345150000025

Controlling the flowrate ratio of two streams in chemical processes poses a challenge due to complex interaction between streams, resulting in nonlinear behaviour and uncertain dynamics. Conventional linear control methods might not be effective to maintain the desired ratio under varying conditions. This study evaluates the efficacy of fuzzy logic controller in controlling the flow ratio of model plant WF922. A comparative analysis is conducted with a conventional proportional integral (PI) controller, assessing their performance using integral time-weighted absolute error (ITAE) and integral absolute error (IAE) as key performance indicators. Optimal control settings were determined as PB=0.047 % and I=0.512 s for PI controller, and e=1 % and Delta e=1 % for fuzzy logic controller. The study reveals that fuzzy logic controller showed better performance than PI controller in terms of set point tracking, with reduced overshoot, faster response, and setting times. The fuzzy logic controller outperformed the PI controller across a wider range of set point values, achieving ITAE values lower than 81 and IAE values lower than 4.2. Furthermore, fuzzy logic controller demonstrated quicker and damped responses for disturbance rejection, resulting in lower ITAE and IAE values across all disturbance magnitudes. The findings of this study highlight the potential advantages of employing fuzzy logic controller strategies in liquid flow systems, offering superior set point tracking and disturbance rejection performance compared to conventional PI controller. The findings are useful for improving control system design in industrial applications.