response of state space to arbitrary input

Using the ss function (https://in.mathworks.com/help/control/ref/ss.html?searchHighlight=ss%20&s_tid=srchtitle_ss%20_1), we can create state space models and we can use step(sys, t) to simulate the step response of the model for a time grid t, however what if i want to give a non-trivial input different from step, like a traingular wave??

Piecewise constants can be modelled by adding signed delayed step responses but how to proceed with any general input that can be even specified in form of an array to accompany time grid?

Thanks

Answer 1

[Star Strider]

‘what if i want to give a non-trivial input different from step, like a traingular wave??’

Use the lsim function. That is the appropriate answer to the second question as well.

Using a system from the lsim documentation and an arbitrary waveform —

A = [-3 -1.5; 5 0];
B = [1; 0];
C = [0.5 1.5];
D = 0;
sys = ss(A,B,C,D);

t = linspace(0, 10, 1500);                                  % Time Vector
u = sum(sin((1:9)'*2*pi*t/2.5));                            % Arbitrary Input

lsim(sys,u,t)
grid on

Experiment with different systems and ‘u’ vectors.

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[Shlok Vaibhav Singh]

Thanks a lot

[Star Strider]

As always, my pleasure!

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