The influence of modeling approach for the MIMO closed-loop systems on the results of simulation in Simulink

Abstract

The paper reports results of comparison of the three approaches for the simulation of the continuous time closed-loop multi input multi output (MIMO) system. In this case the system is described by two firstorder differential equations and represents the real system with two inputs and two outputs. The synthesis of MIMO controller is based on the pole placement method. The controller is tuned by the settings of two adjustable parameters. Simulations are realized in Matlab/Simulink for three cases of representation of the closed-loop system for the same values of parameters in every case. The first one is based on modeling controlled system and the controller in the form of particular transfer functions from each input to an appropriate outputs. Second approach is modification of the first one. The particular transfer functions are modeled in the form of differential equations by the blocks from Simulink libraries. The last simulation approach is also performed by Simulink blocks, for the system modeled directly from the two differential equations description, and controller represented also as two differential equations fulfilling law of control.