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Migrate SDF from Gazebo4 to Gazebo5

Dear community,

we recently try to migrate our SDF model of a simplistic differential wheel drive robot from Gazebo version 4 to 5 (and above). Unfortunately, the kinematic model completely miss behaves in the upper version. Everything works fine in Gazebo 4, but e.g. when we set the velocities of one wheel-joint, the robot jumps away until the wheels rip of. We explicitly set all the inertia, mass, friction coefficients, etc., and it worked fine even with our self written plugins.

Is there any migration manual or "known issues" form porting models from Gazebo 4 to >5?

Kind regards, Tik0

[EDIT] link to sdf: https://github.com/tik0/sdf/tree/master

Asked by tik0 on 2016-03-13 12:47:14 UTC

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Answers

Welcome to gazebo answers! You can find all the API changes that might be causing the problem. Does your code have any new warnings about deprecations?

https://bitbucket.org/osrf/gazebo/src/14a3e6e94163602588f6965f6123f4f777e2e302/Migration.md?fileviewer=file-view-default

Looking at your SDF, the inertias are incorrect. This would explain the wonky physics. image description

I'd check your math on that again. Nonetheless, I tested setting small forces/velocities to the wheels and had no issues (gazebo 7). If you're using jointCmd messages make sure to set all P, I, and D constants even if you want them to be zero.

Asked by Peter Mitrano on 2016-03-13 23:02:56 UTC

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Your link does not provide information about the changes in the SDF parsing behavior. Anyway, the API tells me indeed that the method "physics::JointPtr::SetMaxForces" is deprecated. But I face the strange behavior even without my plugins. Please find the the SDF (without the plugins) here: https://github.com/tik0/sdf/tree/master

Asked by tik0 on 2016-03-15 09:34:09 UTC