Using/Bringing time-variant parameters in/to Simulink
I've been working with Simulink for quite a while already, but now encountered a seemingly simple and common kind of problem, which I still can't seem to find a general solution for. That is, how do you utilize the not-the-very-elementary Simulink blocks for creating time-variant systems?
For example, say you want to simulate the output of a 2nd order linear system by using the Transfer Fcn block. The coefficients for the numerator and denominator polynomials are given as coefficient vectors in the block input dialog. Is there any means to input these coefficients as a function of time? (The Simulink-time preferably.)
Of course one can always transform the simulated function back to time-domain and build the system from scratch (multipliers, integrators/derivatives etc.) - i.e. workarounds may exist - but that's not the point here. (Imagine you couldn't.)
So, is there a way, e.g. by using the Matlab workspace or by using some nice variable definitions in Simulink or by some other means I'm not aware of to generally utilize time-variant parameters in Simulink blocks.
-Antti Pohjoranta, Helsinki