Output of Transfer Function in Sys ID App not the same as workspace

The output of a model is different in the App than in the command line:

From the app

y_sim2 = sim( tf4 , merged(:,[],:));

y2 = y_sim2.OutputData;

realy = merged.OutputData;

%%

figure()

plot(y2{2}, 'Color', 'c')

hold on

plot(realy{2}, 'Color', 'k')

I am wondering why this occurs with the same transfer function and the same input!

Answer 1

[Rajiv Singh]

In addition to the input, you need to ensure that you are using the same initial conditions. See:

Estimate Initial Conditions for Simulating Identified Models - MATLAB & Simulink (mathworks.com)