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Copy of dartsim PR #1437 #5

Merged
merged 3 commits into from
Apr 3, 2020
Merged

Copy of dartsim PR #1437 #5

merged 3 commits into from
Apr 3, 2020

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azeey
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@azeey azeey commented Apr 2, 2020

Copied from dartsim#1437

This resolves issue dartsim#1433 and possibly the other issues mentioned in there. The two changes made in this PR are:

  1. When integrating a FreeJoint's velocity, an additional term is added to account for changing linear velocity in the inertial frame.

  2. The joint velocities of FreeJoint are in se3 and since they are expressed in the body frame, they have to be updated after the joint's positions (SE3) are updated. The same is true for accelerations after velocities are integrated.

This PR breaks a test in test_Dynamics.cpp because integration of the joint positions of FreeJoint updates joint velocities unlike other joint types. I left this as WIP to get some feedback on what to do about this test failure.

From the comments in the upstream PR, this might be a temporary solution and a more permanent solution is in the works. In the meantime, since it fixes a crash in ign-gazebo, it would be nice to get it merged into our local fork

azeey added 3 commits April 2, 2020 10:28
@azeey
Fix issue dartsim#1433
186a99f 
The main fix is in the expression used to integrate velocities. The
secondary fix is to update spatial accelerations after
integrating velocities and to update both spatial velocities and
accelerations after integrating positions.
@azeey
Add regression test for issue dartsim#1193
75a35d8
@azeey
Remove main in test, fix style
cb99035
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azeey commented Apr 2, 2020

/cc @scpeters

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azeey commented Apr 2, 2020

Should we change the version number?

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scpeters commented Apr 3, 2020

I think @j-rivero can update the number when building a debian

@azeey azeey merged commit 711dde3 into azeey/friction_per_shape_more_params Apr 3, 2020
@azeey azeey mentioned this pull request Apr 30, 2020
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@azeey azeey mentioned this pull request Jul 7, 2020
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@azeey azeey mentioned this pull request Aug 20, 2020
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@scpeters scpeters scpeters approved these changes

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