[python-control-discuss] OCF ss initial condition simulation

[Ryan K. <kra...@gv...>]

I have a transfer function and I want to simulate its response to initial
conditions.  Do to this correctly, I think I need to get to OCF so that I
understand the initial conditions of the states (if I thought about it,
maybe I could use C**-1 to find initial conditions for the states in any
form).  control.canonical_form seems prefect:

from control import TransferFunction as TF

diff = TF([1,0],1)
wn = 1.1*2*pi
z = 0.03
so_p = TF(wn,[1,2*z*wn,wn**2])
p = 2*2*pi
pole = TF(p,[1,p])
G = diff*so_p*pole
G

sys1 = control.tf2ss(G)
sys = control.canonical_form(sys1,"observable")

When I run that line, I see my desired C=[[1,0,0]]

But when I try to run the initial_response method, I get an error:

t, y_ol = control.initial_response(sys,t,X0=[100,0,0])

Failure to assume argument is matrix-like in _convertToStateSpace,
result setting an array element with a sequence.

---------------------------------------------------------------------------TypeError
                                Traceback (most recent call
last)<ipython-input-13-9f800e97ff4d> in <module>()----> 1 t, y_ol =
control.initial_response(sys,t,X0=[100,0,0],input=0,output=0)
/usr/local/lib/python3.6/site-packages/control/timeresp.py in
initial_response(sys, T, X0, input, output, transpose, return_x)
619     >>> T, yout = initial_response(sys, T, X0)    620     """-->
621     sys = _get_ss_simo(sys, input, output)    622     623     #
Create time and input vectors; checking is done in
forced_response(...)
/usr/local/lib/python3.6/site-packages/control/timeresp.py in
_get_ss_simo(sys, input, output)    378     If input is not specified,
select first input and issue warning    379     """--> 380     sys_ss
= _convertToStateSpace(sys)    381     if sys_ss.issiso():    382
   return sys_ss
/usr/local/lib/python3.6/site-packages/control/statesp.py in
_convertToStateSpace(sys, **kw)    946             "
_convertToStateSpace, result %s" % e)    947 --> 948     raise
TypeError("Can't convert given type to StateSpace system.")    949
950 # TODO: add discrete time option
TypeError: Can't convert given type to StateSpace system.


It sounds like somehow control.initial_response doesn't recognize sys is ss
or that it is simo.

Am I doing something wrong?  How should I proceed?

Thanks,

Ryan
--
Dr. Ryan Krauss
Associate Professor
Product Design and Manufacturing Engineering
Grand Valley State University