From a86461fc57a3f1c0a8ce1417fc1d13c2001273bc Mon Sep 17 00:00:00 2001
From: Taylor Howell <taylorhowell@google.com>
Date: Wed, 9 Jul 2025 01:58:22 -0700
Subject: [PATCH] Set MJX minimum friction value to mjMINMU.

PiperOrigin-RevId: 780934075
Change-Id: I1ae0b678526218514cc260fdb9f2a62d88394cbe
---
 mjx/mujoco/mjx/_src/collision_driver.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mjx/mujoco/mjx/_src/collision_driver.py b/mjx/mujoco/mjx/_src/collision_driver.py
index 2f45bca8..1ab14cd0 100644
--- a/mjx/mujoco/mjx/_src/collision_driver.py
+++ b/mjx/mujoco/mjx/_src/collision_driver.py
@@ -271,7 +271,7 @@ def _contact_groups(m: Model, d: Data) -> Dict[FunctionKey, Contact]:
       # pair contacts get their params from m.pair_* fields
       params.append((
           m.pair_margin[ip] - m.pair_gap[ip],
-          jp.clip(m.pair_friction[ip], a_min=eps),
+          m.pair_friction[ip],
           m.pair_solref[ip],
           m.pair_solreffriction[ip],
           m.pair_solimp[ip],
@@ -321,7 +321,7 @@ def _contact_groups(m: Model, d: Data) -> Dict[FunctionKey, Contact]:
         pos=None,
         frame=None,
         includemargin=includemargin,
-        friction=friction,
+        friction=jp.maximum(friction, mujoco.mjMINMU),
         solref=solref,
         solreffriction=solreffriction,
         solimp=solimp,