Do you support damping in urdf?

[tkoolen]

Do you support damping in urdf? <dynamics damping="0.6"/> If not, how can I add one?

Originally posted by @Islam0mar in https://github.com/JuliaRobotics/RigidBodyDynamics.jl/issues/317#issuecomment-503895047

[tkoolen]

Opened a new issue for this.

Damping coefficients are not stored in RigidBodyDynamics Joints; in general the dynamics tag for a joint is ignored. The motivation for that is that the friction model in the URDF spec is just one model that I didn't want to get tied down to.

I've used the following code in the past to parse damping values from the URDF after creating a Mechanism (by parsing the same URDF).

https://github.com/tkoolen/QPWalkingControl.jl/blob/master/src/damping.jl

The resulting JointDamping object is callable, and can be used as the control! function with RigidBodySim (possibly combined with other controllers using a SumController). See the cell with comment # create ODEProblem in https://github.com/tkoolen/QPWalkingControl.jl/blob/master/notebooks/Atlas%20walking.ipynb. If you don't want to use RigidBodySim.jl, you can can use the same JointDamping callable object with RigidBodyDynamics.simulate.

I wouldn't actually add a dependency on QPWalkingControl to get this functionality; just copy the file to your own project for now. I think I'll move it to RigidBodyDynamics at some point.

[Islam0mar]

Thanks, I will try that.