Genesis [Feature]: Backlash support

What feature or enhancement are you proposing?

From my experience with robtics one of the biggest params not repersented by simulators is backlash, is quite critical especially when you start to work on manipulation.

Any cleaver ways to implement this ? Without actually computing anything regarding gear meshing.

Potential Benefit

Much better sim2real

Oct 24 '25 16:10 ax-anoop

We will probably implement backlash soon.

Oct 24 '25 18:10 duburcqa

That will be insanely nice

Oct 24 '25 19:10 ax-anoop

For the implementation of backlash, the idea is to add an additional fictitious joint after the true joint, and translate the armature inertia from the "true" joint to the backlash joint. No need to modify the Rigid Solver at all. It is all about modelling of the system. Here is my implementation in C++ for Jiminy simulator: https://github.com/duburcqa/jiminy/blob/accdf3629d9d8c08bb97f2905f010f1616d2168a/core/src/utilities/pinocchio.cc#L550

Oct 24 '25 19:10 duburcqa

How do the two joints integrate with one another ? Is it a compliant coupler ? or coupler with deadzone ?

Oct 24 '25 21:10 ax-anoop

Sorry I should've left it open if it's getting implemented soon (accident)

Oct 24 '25 21:10 ax-anoop