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

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

Looking closer at the traceback showed that the issue is that
control.canonical_form returns a tuple rather than just the system.  So,
slicing the first thing out of the tuple solved my issue:

sys = control.canonical_form(sys1,"observable")[0]

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


On Mon, Nov 25, 2019 at 3:29 PM Ryan Krauss <kra...@gv...> wrote:

> 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
>