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Error with display of inertia

Good day everyone,

I have just signed up here on the forum after having a very strange behaviour with gazebo simulation. Since this problem can also be from my xacro file, I have also posted this question on ROS forum: https://answers.ros.org/question/376336/xacro-strangest-behaviour-with-inertia/ (awaiting moderation).

The issue is the following:

I was designing a robot with xacro and started seing the strangest behaviours from the component. I have a component, which is rotated 90 degrees in the roll axis. The inertia was also rotated (as the visual and collision), but, analysing in gazebo, I see that the inertia ends up not being rotated, as shown in the following image: image description

I thought this behaviour to be very weird and so I tried with a different inertia, this time not the one taken from the CAD but considering that the inertia from the object was represented by a cuboid. So, I used the following inertia (which is very close to the one given by the CAD tool for the object):

<inertia ixx="8.5474390625e-4" ixy="0" ixz="0" iyy="8.5474390625e-4" iyz="0" izz="1.7094878125e-3" />

This time, gazebo couldn't even display the inertia, as shown here: image description

Finally, with a try and error approach, i changed the izz moment of inertia to 1.5e-3, resulting in:

<inertia ixx="8.5474390625e-4" ixy="0" ixz="0" iyy="8.5474390625e-4" iyz="0" izz="1.5e-3" />

This time, i got the inertia to be displayed correctly: image description.

Everything seems correct to me in all the cases (I have only changed the component inertia between trials) so, what may be causing this issue?

Asked by teod on 2021-04-16 06:27:45 UTC

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