Fractional PID Controller Applied to a Chemical Plant with Level and pH Control

摘要

One of the most important processes in the chemical,biological and petrochemical industries is the control of the potential of hydrogen(pH).As it is a multivariable process and non-linear,pH control gives rise to many challenges for designers in both dynamic responses and robustness issues.Despite all this complexity,in many circumstances pH control is performed by using a conventional proportional integral derivative(PID)control,which is very common in industry.This paper proposes using a fractional-order PID to improve the pH control performance of a lab-scale process,as it is more flexible,i.e.,there is a higher number of variables to be adjusted.Results from a simulation have been compared to those from both conventional and fractional-order PID controls,which has shown the better performance of the latter related to important metrics such as the control effort and dynamic response of the controlled variables.