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Tue, 12 Mar 2013 16:35:07 +0000
simmechanics: ground excited model
http://www.mathworks.com/matlabcentral/newsreader/view_thread/327479#899830
pietro
Hi all, <br>
<br>
I'm just trying to develop a ground excited model of single degree of freedom model. The excitation is in terms of displacement. Here you can see the model. <br>
<br>
<a href="http://imageshack.us/f/820/modelqg.png/">http://imageshack.us/f/820/modelqg.png/</a><br>
<br>
I get a huge spike of the body acceleration in the beginning of the simulation. The problem arises from the double integration of the displacement, i.e. the sine wave block. Infact after the first derivative a discontinuity of the first derived signal, as you can see in this plot: <br>
<br>
<a href="http://img829.imageshack.us/img829/3527/signals.png">http://img829.imageshack.us/img829/3527/signals.png</a><br>
<br>
the purple signal is the one of the sine wave block output and the yellow one is of the first derivative block output. As you can see there is the discontinuity. How could I fix this problem? <br>
<br>
Thanks<br>
<br>
cheers<br>
<br>
Pietro

Mon, 18 Mar 2013 08:16:15 +0000
Re: simmechanics: ground excited model
http://www.mathworks.com/matlabcentral/newsreader/view_thread/327479#900262
pietro
"pietro " <bracardi82@email.it> wrote in message <khnlfr$1no$1@newscl01ah.mathworks.com>...<br>
> Hi all, <br>
> <br>
> I'm just trying to develop a ground excited model of single degree of freedom model. The excitation is in terms of displacement. Here you can see the model. <br>
> <br>
> <a href="http://imageshack.us/f/820/modelqg.png/">http://imageshack.us/f/820/modelqg.png/</a><br>
> <br>
> I get a huge spike of the body acceleration in the beginning of the simulation. The problem arises from the double integration of the displacement, i.e. the sine wave block. Infact after the first derivative a discontinuity of the first derived signal, as you can see in this plot: <br>
> <br>
> <a href="http://img829.imageshack.us/img829/3527/signals.png">http://img829.imageshack.us/img829/3527/signals.png</a><br>
> <br>
> the purple signal is the one of the sine wave block output and the yellow one is of the first derivative block output. As you can see there is the discontinuity. How could I fix this problem? <br>
> <br>
> Thanks<br>
> <br>
> cheers<br>
> <br>
> Pietro<br>
<br>
Any help is appreciated<br>
<br>
Thanks