As stated in Drake's documentation on CoulombFriction, while we conceptually think of Coulomb friction coefficients as a joint property of two materials touching each other (and also parameterize it as thus in dair_pll), Drake actually associates a coefficient to each body, and combines them into a lumped parameter.
dair_pll should reflect this underlying parameterization for correct URDF generation.
As stated in Drake's documentation on
CoulombFriction, while we conceptually think of Coulomb friction coefficients as a joint property of two materials touching each other (and also parameterize it as thus indair_pll), Drake actually associates a coefficient to each body, and combines them into a lumped parameter.dair_pllshould reflect this underlying parameterization for correct URDF generation.