Time Delay Compensation for Dialysate Preparing Process Using Immune-LQI Controller

Abstract

Time delay in control systems may cause instability; therefore, it is necessary to compensate for its effect by designing appropriate controller. Time delay is present in the dialysate papering process due to the physical distance between the concentrate injection points and the points of conductivity measurements. In this research, an  Immune-LQI controller which was previously designed to regulate dialysate conductivity, is tested in presence of time delay. The Immune-LQI controller combines Linear Quadratic Integrator (LQI), Immune Control (IC), Fuzzy Logic (FL) and Genetic Algorithm (GA). For the purpose of comparison, the well-known Smith predictor with Proportional Integral Derivative controller (PID-Smith), LQI, and PID have been designed. The results proved the superiority of Immune-LQI as it resulted in 1.70 % improvement in rise time, 77.80 % in overshoot, and 43.47 % in settling time, when compared with LQI.