Computing the Instantaneous Output of a Simulink Model

Hi,

If I have a set of systems of dynamics in closed form:

xdot = f(x,u,t)

then if I want to know the instantaneous value of xdot given current values of x, u, and t, I can simply plug the current values of x, u, and t into f to compute the current value of xdot.

I currently have a Simulink model of an aircraft system and would like to get an instantaneous value of xdot. I know that I can give it an initial condition and a signal u(t) and get a signal xdot(t), but that's not exactly what I want.

Currently, the only thing I can think of is to simulate the model with a step input u for a very short amount of time, setting the initial value of x to the current value of x and taking the first value in the signal xdot(t) that Simulink outputs. Is there a better solution?

Thanks!

Answer 1

[Stephanie]

It looks like simulating Simulink for zero seconds gives me the result that I want.