How to model the intial value of a linear system using Simulink?

Feb 04, 2009 2 Replies

I have seen more than one examples presented in tutorials to show how to model control system in Simulink, most of which reads as below:



r->sum->PID->system Transfer Fcn->y | | -----------------------------------------------



But since transfer function assumes that the initial value in systems should be zero, how can I model a system with intial values together with the transfer function in Simulink?



for example, I have a state-space model like below:



x' = A*x + B*u y = Cu



assuming it is a SISO system, and x(0) should be considered, after I use the ss2tf() function to transform it into a transfer function, then how can I include the x(0) in the Simulink? Considering a case that there are lots of nonlinear parts in the whole system, a simpler treatment using feedback() or lsim() can't work.



Thanks in advance!


Why do you need to model it with transfer function? Why do not you just use the block STATE-SPACE in CONTINUOUS library? It accepts x(0) as on of the input arguments.

-- Z.H.

Thanks,I have to get familiar with the blocks in the Simulink!

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