Why do I get an incorrect step response plot from the Control System Designer?

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Emmett - 2020-11-20T13:50:47+00:00
Question: Why do I get an incorrect step response plot from the Control System Designer?

I am using the Control System Designer in MATLAB R2016b to plot the step response of my closed loop system. When I plot the step response of my transfer function in MATLAB using the "step" function, I get the expected, stable response. When I plot the step response of the same exact system using the Control System Designer, I would expect to get the same step response plotted in MATLAB. However, I get a different, unstable result. How can I resolve this discrepancy and see the correct output in the Control System Designer?

Expert Answer

Profile picture of Kshitij Singh Kshitij Singh answered . 2025-11-20

This is a known bug that has been fixed in MATLAB R2017b. This bug could apply when you have built your system using either the second or third configurations in the "edit architecture" window. You can resolve this bug without upgrading your MATLAB installation by following the instructions under "Workaround" on . These steps will guide you through installing a patch that fixes this issue. Afterwards, the Control System Designer should behave as expected with your system.


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