python-control-discuss

[python-control-discuss] some problems with control-0.6c

[Roberto B. <rob...@su...>]

Hi all

I'm testing the last control-0.6c toolbox in order to actualize my
yottalab package and I found some differences between the results of a
couple of functions:

1) the c2d function should maintain the form of the state-space
function. It seems that the system is first transformed into a transfer
function and then discretized. In my opinion it is important that the
state-space form of the discrete system is exactly the same (same
states) that I have in the continuous representation.

2) The dare functions gives some wrong results, and I'll check the lqr
function asap. Using the delivered "dare" function (mateqn.py) I have
wrong values of the feedback gains (compared with the values given by
matlab dlqr and scilab)

3) the lqr function doesn't accept a call like 

lqr(sys,Q,R) -> only 3 parameters!


In the next time I'll check the gains returned by the lqr function,
compared with matlab and scilab.

Best regards

Roberto

Re: [python-control-discuss] some problems with control-0.6c

[Rene v. P. <ren...@gm...>]

I added capability for c2d to convert MIMO state-space systems, based on a
slycot function added to the repagh/slycot on github, so you need a new
slycot for that.

Thanks for the testing, by the way!

René


On 17 December 2013 11:25, Roberto Bucher <rob...@su...> wrote:

> Hi all
>
> I'm testing the last control-0.6c toolbox in order to actualize my
> yottalab package and I found some differences between the results of a
> couple of functions:
>
> 1) the c2d function should maintain the form of the state-space
> function. It seems that the system is first transformed into a transfer
> function and then discretized. In my opinion it is important that the
> state-space form of the discrete system is exactly the same (same
> states) that I have in the continuous representation.
>
> 2) The dare functions gives some wrong results, and I'll check the lqr
> function asap. Using the delivered "dare" function (mateqn.py) I have
> wrong values of the feedback gains (compared with the values given by
> matlab dlqr and scilab)
>
> 3) the lqr function doesn't accept a call like
>
> lqr(sys,Q,R) -> only 3 parameters!
>
>
> In the next time I'll check the gains returned by the lqr function,
> compared with matlab and scilab.
>
> Best regards
>
> Roberto
>
>
>
>
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-- 
René van Paassen        | ______o____/_|     Ren...@gm...
                       <[___\_\_-----<               t: +31 15 2628685
                        |  o'                   mobile: +31 6 39846891

Re: [python-control-discuss] some problems with control-0.6c

[Roberto B. <rob...@su...>]

After the first tests it seems to be ok.

On next Monday I'll try to regenerate RT code using the modified control 
scripts and I'll test the results in my laboratory.

Thanks

Roberto

On 05/23/2014 02:47 PM, Rene van Paassen wrote:
> I added capability for c2d to convert MIMO state-space systems, based 
> on a slycot function added to the repagh/slycot on github, so you need 
> a new slycot for that.
>
> Thanks for the testing, by the way!
>
> René
>
>
> On 17 December 2013 11:25, Roberto Bucher <rob...@su... 
> <mailto:rob...@su...>> wrote:
>
>     Hi all
>
>     I'm testing the last control-0.6c toolbox in order to actualize my
>     yottalab package and I found some differences between the results of a
>     couple of functions:
>
>     1) the c2d function should maintain the form of the state-space
>     function. It seems that the system is first transformed into a
>     transfer
>     function and then discretized. In my opinion it is important that the
>     state-space form of the discrete system is exactly the same (same
>     states) that I have in the continuous representation.
>
>     2) The dare functions gives some wrong results, and I'll check the lqr
>     function asap. Using the delivered "dare" function (mateqn.py) I have
>     wrong values of the feedback gains (compared with the values given by
>     matlab dlqr and scilab)
>
>     3) the lqr function doesn't accept a call like
>
>     lqr(sys,Q,R) -> only 3 parameters!
>
>
>     In the next time I'll check the gains returned by the lqr function,
>     compared with matlab and scilab.
>
>     Best regards
>
>     Roberto
>
>
>
>     ------------------------------------------------------------------------------
>     Rapidly troubleshoot problems before they affect your business.
>     Most IT
>     organizations don't have a clear picture of how application
>     performance
>     affects their revenue. With AppDynamics, you get 100% visibility
>     into your
>     Java,.NET, & PHP application. Start your 15-day FREE TRIAL of
>     AppDynamics Pro!
>     http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.clktrk
>     _______________________________________________
>     python-control-discuss mailing list
>     pyt...@li...
>     <mailto:pyt...@li...>
>     https://lists.sourceforge.net/lists/listinfo/python-control-discuss
>
>
>
>
> -- 
> René van Paassen        | ______o____/_| Ren...@gm... 
> <mailto:Ren...@gm...>
> <[___\_\_-----<               t: +31 15 2628685
> |  o'                   mobile: +31 6 39846891
>
>
>
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