Fix base_com body name mismatch for non-base robots

The base_com event in velocity_env_cfg.py hardcodes body_names="base",
but 6 rough envs use different base body names. Override per-env:
- a1, go1: set body_names to "trunk"
- digit: set body_names to "torso_base"
- g1, h1, cassie: disable base_com (consistent with add_base_mass=None)

Verified with 300-iter PhysX/Newton parity tests on all 7 working envs.

Author: hujc7

source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/config/a1/rough_env_cfg.py

@@ -56,6 +56,7 @@ def __post_init__(self):
         self.events.add_base_mass.params["asset_cfg"].body_names = "trunk"
         self.events.add_base_mass.params["mass_distribution_params"] = (-1.0, 3.0)
         self.events.base_external_force_torque.params["asset_cfg"].body_names = "trunk"
+        self.events.base_com.default.params["asset_cfg"].body_names = "trunk"
 
         # reduce action scale
         self.actions.joint_pos.scale = 0.25

source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/config/cassie/rough_env_cfg.py

@@ -88,6 +88,7 @@ def __post_init__(self):
 
         # Cassie uses "pelvis" as base body — disable mass randomization for bipeds
         self.events.add_base_mass = None
+        self.events.base_com = None
         self.events.base_external_force_torque.params["asset_cfg"].body_names = ".*pelvis"
 
         # actions

source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/config/digit/rough_env_cfg.py

@@ -257,6 +257,7 @@ def __post_init__(self):
         # Digit uses "torso_base" as base body
         self.events.add_base_mass.params["asset_cfg"].body_names = "torso_base"
         self.events.base_external_force_torque.params["asset_cfg"].body_names = "torso_base"
+        self.events.base_com.default.params["asset_cfg"].body_names = "torso_base"
 
         # Override actuator to target only actuated joints. Digit has ball joints (rod constraints)
         # that MuJoCo represents with 4 DoFs instead of 3, inflating joint_pos to 74 columns while

source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/config/g1/rough_env_cfg.py

@@ -141,6 +141,7 @@ def __post_init__(self):
 
         # G1 uses "torso_link" as base body — disable mass randomization for bipeds
         self.events.add_base_mass = None
+        self.events.base_com = None
         self.events.base_external_force_torque.params["asset_cfg"].body_names = "torso_link"
 
         # Rewards

source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/config/go1/rough_env_cfg.py

@@ -56,6 +56,7 @@ def __post_init__(self):
         self.events.add_base_mass.params["asset_cfg"].body_names = "trunk"
         self.events.add_base_mass.params["mass_distribution_params"] = (-1.0, 3.0)
         self.events.base_external_force_torque.params["asset_cfg"].body_names = "trunk"
+        self.events.base_com.default.params["asset_cfg"].body_names = "trunk"
 
         # reduce action scale
         self.actions.joint_pos.scale = 0.25

source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/config/h1/rough_env_cfg.py

@@ -109,6 +109,7 @@ def __post_init__(self):
 
         # H1 uses "torso_link" as base body — disable mass randomization for bipeds
         self.events.add_base_mass = None
+        self.events.base_com = None
         self.events.base_external_force_torque.params["asset_cfg"].body_names = ".*torso_link"
 
         # Rewards