Multi-Tank Level Control Using Internal Model Control and Internal Model Cascade Control

Abstract

This project deals with the study, design and application of IMC (Internal Model Control) and IMCC (Internal Model Cascade Control) strategies for an unconstrained single input and single output system. Both strategies have been studied by applying them on a Tank Level Control System under varying system as well as input parameters. The application of both strategies on the model of the system is done and step responses of the modeled system under different operating conditions are analyzed to deduce various conclusions. Based on various performance parameters a tuning rule for best tuning parameter to give optimal performance has been designed. It also consist the comparison of various control strategies like PID and PID cascade with above two strategies with different tank configurations. An improvement is also added to IMC for improvement in disturbance rejection. IMC consists of single tuning parameter which is filter coefficient of the main loop controller whereas IMCC consists two tuning parameters, one of primary loop and other for the secondary loop. An important thing is that for designing of IMC and IMCC controllers modeling of the experimental setup has been done. The MATLAB and SIMULINK software has been used for designing of the IMC and IMCC controllers, which were designed considering deduced process model as original process. For IMCC, the secondary process is taken to be control valve. At last an Empirical formula for IMC has been derived which gives the value of best tuning parameter for a given process, based on given performance indices like Rise Time, Settling Time, Peak Time and Peak Overshoot.