osrf / drcsim

Repository for the DRC project.
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Clarify atlas_v4 model differences #467

Open osrf-migration opened 9 years ago

osrf-migration commented 9 years ago

Original report (archived issue) by Stefan Kohlbrecher (Bitbucket: Stefan_Kohlbrecher).


There are two atlas_v4 version with different joint configurations:

atlas_v4.urdf has 6 arm DOF

atlas_v4_simple_shapes has 7 DOF (like v5), but the final wry2 joints are limited to a very small range from -0.001 to 0.001. This appears to be used as standard for drcsim right now

What's the rationale behind this and will this be changed in the future? I'm looking at the drcsim_4.2_prerelease branch which is the one recommended for use I think.

osrf-migration commented 9 years ago

Original comment by Stefan Kohlbrecher (Bitbucket: Stefan_Kohlbrecher).


Ok, what I noticed is that atlas v4 with wry2 joints changed to fixed will fall immediately as controller fails to initialize.

osrf-migration commented 9 years ago

Original comment by Nate Koenig (Bitbucket: Nathan Koenig).


I'll look into updating atlas_v4.urdf to match atlas_v4_simple_shapes.urdf.

The oddity with the wry2 joints are in place as a means to make the bdi controller work on both atlas v5 and atlas v4.

osrf-migration commented 9 years ago

Original comment by Mathew DeDonato (Bitbucket: mdedonato NA).


We have been told that the models are the best way for us to get the kinematics of the robot. We use these models in all aspects of our code, not only for visualization. Because of this it is very important for them to be accurate. Can you let us know which model is the most accurate and which one we should use for our kinematics?

Also, how accurate are your models of the multisense and robotiq hands?

osrf-migration commented 9 years ago

Original comment by Nate Koenig (Bitbucket: Nathan Koenig).


We have worked with BDI and teams to make the models as accurate as possible. We don't have an Atlas, so it's not possible for us to validate the model. The same holds for multisense and robotiq hands.

If you find any problems, please let us know.

osrf-migration commented 9 years ago

Original comment by John Hsu (Bitbucket: hsu, GitHub: hsu).


osrf-migration commented 9 years ago

Original comment by John Hsu (Bitbucket: hsu, GitHub: hsu).


The new models should be kinematically correct (i.e. matching DOFs) but un-validated against physical robots by OSRF.

Tagging @BillBlank in case there are any additional comments on accuracy of model. Thanks!

osrf-migration commented 9 years ago

Original comment by Bill Blank (Bitbucket: BillBlank).


Right, the new values in atlas_v4_simple_shapes.urdf and atlas_v5_simple_shapes.urdf are correct.

osrf-migration commented 9 years ago

Original comment by Twan Koolen (Bitbucket: tkoolen).


Related: issue #492