Mathematical Model for Identification of an Interacting Two-tank Level Control System

Abstract

The objectives of this research were: 1) to find a mathematical model of the interactive two-tank level control system and 2) to study the step response of the interactive two-tank level control based on simulations with Matlab Simulink and experiments. The method of conducting research is an experimental research of 5 steps, i.e. experimental design, determining model structure, parameter estimation model validation, assessment model conclusion and verification. Defining for a mathematical model was used to create differential equations while laplace transform and block diagram algebra were used to find the transfer function of system. The parameters of system can be obtained by analyzing the response obtained from the experiment.

     The resulting mathematical model is written in the form of a second order system transfer function. The open loop response is over damped response. The process gain is one. The step response form Matlab Simulink program when the variable input signal was tuned to a stepped signal at 0–30 %. The steady state response was 30 % with the steady state time of 20 minutes. The results from the experiment showed that the steady state response was 32 % with an error of -6.67 %. The steady state time was 18 minutes with an error of 10 %. Both responses were considered as a similar value which tended to go in the same direction. Therefore, the mathematical models obtained from the research can be systematically identified for a representative of the system for designing controls and predicting responses that will occur in the future. The experimental set can be used as teaching materials for the control system.