Implement Coulomb joint friction in DARTJoint

[osrf-migration]

Original report (archived issue) by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

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This is a parallel of #381 for dart. We want to implement Coulomb joint friction in dart.

@karenliu @jslee02

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Original comment by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

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In addition to the ODE implementation discussed in #381, here's a Simbody example program that implements a torque-limited speed constraint on a joint:

https://github.com/simbody/simbody/blob/master/Simbody/examples/ExampleMotor-TorqueLimited-Constraint.cpp

[osrf-migration]

Original comment by Jeongseok Lee (Bitbucket: jlee02, GitHub: jslee02).

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Coulomb joint friction is implemented in DART, and it will be included in DART 4.3 (planned to be released around Jan 19).

[osrf-migration]

Original comment by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

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I just tested this, and it's partially working, but it seems to be dependent on the time step. Possibly you are interpreting the friction coefficient as an impulse rather than a force? I can report this in the dart issue tracker if necessary.

[osrf-migration]

Original comment by Jeongseok Lee (Bitbucket: jlee02, GitHub: jslee02).

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You are correct. The friction is regarded as an impulse, which shouldn't be. I'll fix it soon.

[osrf-migration]

Original comment by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

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Thanks! For reference, ODE regards it as a force, while bullet regards it as an impulse. I think it's easier from a modelling perspective as a force.

[osrf-migration]

Original comment by Jeongseok Lee (Bitbucket: jlee02, GitHub: jslee02).

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Fixed by this PR and it's included in dart 4.3.3.

[osrf-migration]

Original comment by Jeongseok Lee (Bitbucket: jlee02, GitHub: jslee02).

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Joint friction is implemented.

It's still partially working. DART cannot handle joint limit constraints and joint friction together for now. It's reported to dart repo.

[osrf-migration]

Original comment by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

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Thanks @jslee02 ! I've pulled in that branch and added a few small changes. I will submit a pull request for it after pull request #1404 is merged.

https://osrf-migration.github.io/gazebo-gh-pages/#!/osrf/gazebo/commits/branch/dart_joint_friction

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Original comment by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

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I just submitted this branch in pull request #1427

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Original comment by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

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• changed state from "new" to "resolved"

pull request #1427

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

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• set version to "all"

[osrf-migration]

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

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• changed state from "resolved" to "closed"