Simulink Plot for damping ratio of second order systems

I am trying to plot several signals that correspond to different damping ratios on one plot in Simulink. Rather than creating several transfer functions corresponding to each damping ratio and then using MUX, how might I do this using Simulink? Is there a way to create a vector with all my damping ratio arguments and then have Simulink go through them all?

Answer 1

[Sebastian Castro]

Many Simulink blocks support multidimensional signals.

If you enter an array for the Gain (?) block where your damping ratio is specified, such as For example, [0.1 0.5 1 5 10], what do you see in the visualization results?

If all the blocks in the model work with arrays, you should see your output would be a 5-element signal.

- Sebastian

[Meena Farag]

The damping ratio is specified in the denominator of the transfer function, it's not a gain factor. The problem is that the denominator of the transfer function block in Simulink only accepts row vectors (not matrices, as is the case for the numerator) corresponding to the polynomial coefficients of the transfer function denominator.

[Sebastian Castro]

If you have the Control System Toolbox, you can create a multi-output transfer function variable and then use that in a model with an LTI System block.

Here's what I tried and it works well:

% Create a 10-output transfer function in a for-loop
for i = 1:10
 sys(i,1) = tf(1,[1 i 2*i]);
end

By the way, if you don't have the toolbox, what I would recommend is doing a parameter; that is, performing multiple simulations with different values, collecting the results in MATLAB, and plotting them yourself.

- Sebastian