Time response of modes to an impulse

Hi.

For a 4x4 plant matrix, I want to see the time response of short period mode and phugoid mode of an aircraft for an initial perturbation, respectively. I have 2 roots of the plant matrix for both short period mode and phugoid mode and corresponding period times. How can I plot the responses of the 4 variables with specified initial conditions for an elevator angle deflection?

Thanks.

Answer 1

[Star Strider]

If I understand correctly what you want, it is possible to return the state trajectories with lsim as described in Extract Simulated Response Data. The impulse and step functions also have this option.

[Turgut Ataseven]

@Star Strider Thanks for the response.

My aim is to get the responses of two modes (short and long period) of the plant matrix to a perturbation of -10 and get something like the image below. I have 2+2 eigenvectors and 2 period times for the modes. "Isim" documentation could not help me much.

[Star Strider]

I posted my best guess as to what might be appropriate in the context of a request without a defined model or an example of what the desired result is. That is still the best I can do.

The lsim funciton allows you to specify the input as a function of time, while the impulse and step functions supply specific inputs. All of them can output the system response as well as the state trajectories, and in the absence of further clarification, that is what I believe your post requested.