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Crazy behaviour from a simple "board-like" model

Im building a more complex model but i created a simple one to start. It has a very weird behaviour that i documented by video so you can all give your opinions !! VIDEO ---------> VIDEO

In the video it is visible the SDF for the model. I made my world setup using this:

<physics type='ode'>
  <max_step_size>0.015</max_step_size>
  <real_time_update_rate>67</real_time_update_rate>
  <gravity>0 0 -9.8</gravity>
</physics>

But works the same way with or without it. May be its STL related ? Can figure it out.

Asked by wicked88 on 2016-09-20 19:27:24 UTC

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Answers

It looks like the center of mass is below the ground. You can check it by choosing View -> Center of Mass

Asked by chapulina on 2016-09-20 19:59:54 UTC

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yea your inertia is also probably wrong

Asked by Peter Mitrano on 2016-09-21 00:16:01 UTC

Yes you are right @chapulinha ! How do i change the center of mass ??? Also, any way to correctly compute the inertia of something ?

Asked by wicked88 on 2016-09-21 04:56:36 UTC

Take a look at the inertial SDF syntax: http://sdformat.org/spec?ver=1.6&elem=link#link_inertial There are also many examples here: https://bitbucket.org/osrf/gazebo_models This page has good info on moments of interia: https://en.wikipedia.org/wiki/List_of_moments_of_inertia

Asked by nkoenig on 2016-09-21 08:47:44 UTC

Thank you all for your answers ! I've already corrected my center of mass of the models and the building is going fine, no odd stupid behaviours now. Although, i still didnt manage to work on my values for the moments of inertia which are crucial to obtain a truthful simulation

Asked by wicked88 on 2016-09-21 09:27:09 UTC

This tutorial might help you with the inertias: http://gazebosim.org/tutorials?tut=inertia&cat=build_robot

Asked by chapulina on 2016-09-21 09:42:06 UTC