Tweak velocity task.

src/mjlab/tasks/velocity/config/g1/env_cfgs.py

@@ -70,7 +70,16 @@ def unitree_g1_rough_env_cfg(play: bool = False) -> ManagerBasedRlEnvCfg:
   ].site_names = site_names
 
   cfg.events["foot_friction"].params["asset_cfg"].geom_names = geom_names
-
+  cfg.events["base_com"].params["asset_cfg"].body_names = ("torso_link",)
+
+  # Rationale for std values:
+  # - Knees/hip_pitch get the loosest std to allow natural leg bending during stride.
+  # - Hip roll/yaw stay tighter to prevent excessive lateral sway and keep gait stable.
+  # - Ankle roll is very tight for balance; ankle pitch looser for foot clearance.
+  # - Waist roll/pitch stay tight to keep the torso upright and stable.
+  # - Shoulders/elbows get moderate freedom for natural arm swing during walking.
+  # - Wrists are loose (0.3) since they don't affect balance much.
+  # Running values are ~1.5-2x walking values to accommodate larger motion range.
   cfg.rewards["pose"].params["std_standing"] = {".*": 0.05}
   cfg.rewards["pose"].params["std_walking"] = {
     # Lower body.

src/mjlab/tasks/velocity/config/go1/env_cfgs.py

@@ -64,6 +64,7 @@ def unitree_go1_rough_env_cfg(play: bool = False) -> ManagerBasedRlEnvCfg:
   ].site_names = site_names
 
   cfg.events["foot_friction"].params["asset_cfg"].geom_names = geom_names
+  cfg.events["base_com"].params["asset_cfg"].body_names = ("trunk",)
 
   cfg.rewards["pose"].params["std_standing"] = {
     r".*(FR|FL|RR|RL)_(hip|thigh)_joint.*": 0.05,

src/mjlab/tasks/velocity/mdp/rewards.py

@@ -289,7 +289,20 @@ def soft_landing(
 
 
 class variable_posture:
-  """Penalize deviation from default pose, with tighter constraints when standing."""
+  """Penalize deviation from default pose with speed-dependent tolerance.
+
+  Uses per-joint standard deviations to control how much each joint can deviate
+  from default pose. Smaller std = stricter (less deviation allowed), larger
+  std = more forgiving. The reward is: exp(-mean(error² / std²))
+
+  Three speed regimes (based on linear + angular command velocity):
+    - std_standing (speed < walking_threshold): Tight tolerance for holding pose.
+    - std_walking (walking_threshold <= speed < running_threshold): Moderate.
+    - std_running (speed >= running_threshold): Loose tolerance for large motion.
+
+  Tune std values per joint based on how much motion that joint needs at each
+  speed. Map joint name patterns to std values, e.g. {".*knee.*": 0.35}.
+  """
 
   def __init__(self, cfg: RewardTermCfg, env: ManagerBasedRlEnv):
     asset: Entity = env.scene[cfg.params["asset_cfg"].name]

src/mjlab/tasks/velocity/velocity_env_cfg.py

@@ -161,7 +161,16 @@ def make_velocity_env_cfg() -> ManagerBasedRlEnvCfg:
       func=mdp.push_by_setting_velocity,
       mode="interval",
       interval_range_s=(1.0, 3.0),
-      params={"velocity_range": {"x": (-0.5, 0.5), "y": (-0.5, 0.5)}},
+      params={
+        "velocity_range": {
+          "x": (-0.5, 0.5),
+          "y": (-0.5, 0.5),
+          "z": (-0.4, 0.4),
+          "roll": (-0.52, 0.52),
+          "pitch": (-0.52, 0.52),
+          "yaw": (-0.78, 0.78),
+        },
+      },
     ),
     "foot_friction": EventTermCfg(
       mode="startup",
@@ -174,6 +183,29 @@ def make_velocity_env_cfg() -> ManagerBasedRlEnvCfg:
         "ranges": (0.3, 1.2),
       },
     ),
+    "encoder_bias": EventTermCfg(
+      mode="startup",
+      func=mdp.randomize_encoder_bias,
+      params={
+        "asset_cfg": SceneEntityCfg("robot"),
+        "bias_range": (-0.015, 0.015),
+      },
+    ),
+    "base_com": EventTermCfg(
+      mode="startup",
+      func=mdp.randomize_field,
+      domain_randomization=True,
+      params={
+        "asset_cfg": SceneEntityCfg("robot", body_names=()),  # Set per-robot.
+        "operation": "add",
+        "field": "body_ipos",
+        "ranges": {
+          0: (-0.025, 0.025),
+          1: (-0.025, 0.025),
+          2: (-0.03, 0.03),
+        },
+      },
+    ),
   }
 
   ##