Adds digit locomotion examples (#1892)

# Description

Add an example to train a locomotion and loco-manipulation controller
for digit. This also serves as an example on how to train a robot with
closed loops.

## Type of change

- New feature (non-breaking change which adds functionality)

## Screenshots



## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

---------
Signed-off-by: lgulich <22480644+lgulich@users.noreply.github.com>
Co-authored-by: Kelly Guo <kellyg@nvidia.com>
Co-authored-by: Kelly Guo <kellyguo123@hotmail.com>

docs/source/overview/environments.rst

@@ -288,6 +288,12 @@ Environments based on legged locomotion tasks.
     +------------------------------+----------------------------------------------+------------------------------------------------------------------------------+
     | |velocity-rough-g1|          | |velocity-rough-g1-link|                     | Track a velocity command on rough terrain with the Unitree G1 robot          |
     +------------------------------+----------------------------------------------+------------------------------------------------------------------------------+
+    | |velocity-flat-digit|        | |velocity-flat-digit-link|                   | Track a velocity command on flat terrain with the Agility Digit robot        |
+    +------------------------------+----------------------------------------------+------------------------------------------------------------------------------+
+    | |velocity-rough-digit|       | |velocity-rough-digit-link|                  | Track a velocity command on rough terrain with the Agility Digit robot       |
+    +------------------------------+----------------------------------------------+------------------------------------------------------------------------------+
+    | |tracking-loco-manip-digit|  | |tracking-loco-manip-digit-link|             | Track a root velocity and hand pose command with the Agility Digit robot     |
+    +------------------------------+----------------------------------------------+------------------------------------------------------------------------------+
 
 .. |velocity-flat-anymal-b-link| replace:: `Isaac-Velocity-Flat-Anymal-B-v0 <https://github.com/isaac-sim/IsaacLab/blob/main/source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/config/anymal_b/flat_env_cfg.py>`__
 .. |velocity-rough-anymal-b-link| replace:: `Isaac-Velocity-Rough-Anymal-B-v0 <https://github.com/isaac-sim/IsaacLab/blob/main/source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/config/anymal_b/rough_env_cfg.py>`__
@@ -318,6 +324,9 @@ Environments based on legged locomotion tasks.
 .. |velocity-flat-g1-link| replace:: `Isaac-Velocity-Flat-G1-v0 <https://github.com/isaac-sim/IsaacLab/blob/main/source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/config/g1/flat_env_cfg.py>`__
 .. |velocity-rough-g1-link| replace:: `Isaac-Velocity-Rough-G1-v0 <https://github.com/isaac-sim/IsaacLab/blob/main/source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/config/g1/rough_env_cfg.py>`__
 
+.. |velocity-flat-digit-link| replace:: `Isaac-Velocity-Flat-Digit-v0 <https://github.com/isaac-sim/IsaacLab/blob/main/source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/config/digit/flat_env_cfg.py>`__
+.. |velocity-rough-digit-link| replace:: `Isaac-Velocity-Rough-Digit-v0 <https://github.com/isaac-sim/IsaacLab/blob/main/source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/config/digit/rough_env_cfg.py>`__
+.. |tracking-loco-manip-digit-link| replace:: `Isaac-Tracking-Flat-Digit-v0 <https://github.com/isaac-sim/IsaacLab/blob/main/source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/tracking/config/digit/loco_manip_env_cfg.py>`__
 
 .. |velocity-flat-anymal-b| image:: ../_static/tasks/locomotion/anymal_b_flat.jpg
 .. |velocity-rough-anymal-b| image:: ../_static/tasks/locomotion/anymal_b_rough.jpg
@@ -336,6 +345,9 @@ Environments based on legged locomotion tasks.
 .. |velocity-rough-h1| image:: ../_static/tasks/locomotion/h1_rough.jpg
 .. |velocity-flat-g1| image:: ../_static/tasks/locomotion/g1_flat.jpg
 .. |velocity-rough-g1| image:: ../_static/tasks/locomotion/g1_rough.jpg
+.. |velocity-flat-digit| image:: ../_static/tasks/locomotion/agility_digit_flat.jpg
+.. |velocity-rough-digit| image:: ../_static/tasks/locomotion/agility_digit_rough.jpg
+.. |tracking-loco-manip-digit| image:: ../_static/tasks/locomotion/agility_digit_loco_manip.jpg
 
 Navigation
 ~~~~~~~~~~
@@ -765,6 +777,10 @@ inferencing, including reading from an already trained checkpoint and disabling
       -
       - Manager Based
       -
+    * - Isaac-Tracking-LocoManip-Digit-v0
+      - Isaac-Tracking-LocoManip-Digit-Play-v0
+      - Manager Based
+      - **rsl_rl** (PPO)
     * - Isaac-Navigation-Flat-Anymal-C-v0
       - Isaac-Navigation-Flat-Anymal-C-Play-v0
       - Manager Based
@@ -873,6 +889,10 @@ inferencing, including reading from an already trained checkpoint and disabling
       - Isaac-Velocity-Flat-Cassie-Play-v0
       - Manager Based
       - **rsl_rl** (PPO), **skrl** (PPO)
+    * - Isaac-Velocity-Flat-Digit-v0
+      - Isaac-Velocity-Flat-Digit-Play-v0
+      - Manager Based
+      - **rsl_rl** (PPO)
     * - Isaac-Velocity-Flat-G1-v0
       - Isaac-Velocity-Flat-G1-Play-v0
       - Manager Based
@@ -917,6 +937,10 @@ inferencing, including reading from an already trained checkpoint and disabling
       - Isaac-Velocity-Rough-Cassie-Play-v0
       - Manager Based
       - **rsl_rl** (PPO), **skrl** (PPO)
+    * - Isaac-Velocity-Rough-Digit-v0
+      - Isaac-Velocity-Rough-Digit-Play-v0
+      - Manager Based
+      - **rsl_rl** (PPO)
     * - Isaac-Velocity-Rough-G1-v0
       - Isaac-Velocity-Rough-G1-Play-v0
       - Manager Based

source/isaaclab/isaaclab/envs/mdp/rewards.py

@@ -268,6 +268,16 @@ def undesired_contacts(env: ManagerBasedRLEnv, threshold: float, sensor_cfg: Sce
     return torch.sum(is_contact, dim=1)
 
 
+def desired_contacts(env, sensor_cfg: SceneEntityCfg, threshold: float = 1.0) -> torch.Tensor:
+    """Penalize if none of the desired contacts are present."""
+    contact_sensor: ContactSensor = env.scene.sensors[sensor_cfg.name]
+    contacts = (
+        contact_sensor.data.net_forces_w_history[:, :, sensor_cfg.body_ids, :].norm(dim=-1).max(dim=1)[0] > threshold
+    )
+    zero_contact = (~contacts).all(dim=1)
+    return 1.0 * zero_contact
+
+
 def contact_forces(env: ManagerBasedRLEnv, threshold: float, sensor_cfg: SceneEntityCfg) -> torch.Tensor:
     """Penalize contact forces as the amount of violations of the net contact force."""
     # extract the used quantities (to enable type-hinting)

source/isaaclab_assets/isaaclab_assets/robots/agility.py

+# Copyright (c) 2022-2025, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+import isaaclab.sim as sim_utils
+from isaaclab.actuators import ImplicitActuatorCfg
+from isaaclab.assets.articulation import ArticulationCfg
+from isaaclab.utils.assets import ISAAC_NUCLEUS_DIR
+
+LEG_JOINT_NAMES = [
+    ".*_hip_roll",
+    ".*_hip_yaw",
+    ".*_hip_pitch",
+    ".*_knee",
+    ".*_toe_a",
+    ".*_toe_b",
+]
+
+ARM_JOINT_NAMES = [".*_arm_.*"]
+
+
+DIGIT_V4_CFG = ArticulationCfg(
+    spawn=sim_utils.UsdFileCfg(
+        usd_path=f"{ISAAC_NUCLEUS_DIR}/Robots/Agility/Digit/digit_v4.usd",
+        activate_contact_sensors=True,
+    ),
+    init_state=ArticulationCfg.InitialStateCfg(
+        pos=(0.0, 0.0, 1.05),
+    ),
+    soft_joint_pos_limit_factor=0.9,
+    actuators={
+        "all": ImplicitActuatorCfg(
+            joint_names_expr=".*",
+            stiffness=None,
+            damping=None,
+        ),
+    },
+)

source/isaaclab_tasks/isaaclab_tasks/manager_based/loco_manipulation/__init__.py

+# Copyright (c) 2022-2025, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+"""Locomotion environments for legged robots."""
+
+from .tracking import *  # noqa

source/isaaclab_tasks/isaaclab_tasks/manager_based/loco_manipulation/tracking/__init__.py

+# Copyright (c) 2022-2025, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause

source/isaaclab_tasks/isaaclab_tasks/manager_based/loco_manipulation/tracking/config/__init__.py

+# Copyright (c) 2022-2025, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause

source/isaaclab_tasks/isaaclab_tasks/manager_based/loco_manipulation/tracking/config/digit/__init__.py

+# Copyright (c) 2022-2025, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+import gymnasium as gym
+
+from . import agents
+
+##
+# Register Gym environments.
+##
+gym.register(
+    id="Isaac-Tracking-LocoManip-Digit-v0",
+    entry_point="isaaclab.envs:ManagerBasedRLEnv",
+    disable_env_checker=True,
+    kwargs={
+        "env_cfg_entry_point": f"{__name__}.loco_manip_env_cfg:DigitLocoManipEnvCfg",
+        "rsl_rl_cfg_entry_point": f"{agents.__name__}.rsl_rl_ppo_cfg:DigitLocoManipPPORunnerCfg",
+    },
+)
+
+
+gym.register(
+    id="Isaac-Tracking-LocoManip-Digit-Play-v0",
+    entry_point="isaaclab.envs:ManagerBasedRLEnv",
+    disable_env_checker=True,
+    kwargs={
+        "env_cfg_entry_point": f"{__name__}.loco_manip_env_cfg:DigitLocoManipEnvCfg_PLAY",
+        "rsl_rl_cfg_entry_point": f"{agents.__name__}.rsl_rl_ppo_cfg:DigitLocoManipPPORunnerCfg",
+    },
+)

source/isaaclab_tasks/isaaclab_tasks/manager_based/loco_manipulation/tracking/config/digit/agents/__init__.py

+# Copyright (c) 2022-2025, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause

source/isaaclab_tasks/isaaclab_tasks/manager_based/loco_manipulation/tracking/config/digit/agents/rsl_rl_ppo_cfg.py

+# Copyright (c) 2022-2025, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+from isaaclab.utils import configclass
+
+from isaaclab_rl.rsl_rl import RslRlOnPolicyRunnerCfg, RslRlPpoActorCriticCfg, RslRlPpoAlgorithmCfg
+
+
+@configclass
+class DigitLocoManipPPORunnerCfg(RslRlOnPolicyRunnerCfg):
+    num_steps_per_env = 24
+    max_iterations = 2000
+    save_interval = 50
+    experiment_name = "digit_loco_manip"
+    empirical_normalization = False
+    policy = RslRlPpoActorCriticCfg(
+        init_noise_std=1.0,
+        actor_hidden_dims=[256, 128, 128],
+        critic_hidden_dims=[256, 128, 128],
+        activation="elu",
+    )
+    algorithm = RslRlPpoAlgorithmCfg(
+        value_loss_coef=1.0,
+        use_clipped_value_loss=True,
+        clip_param=0.2,
+        entropy_coef=0.01,
+        num_learning_epochs=5,
+        num_mini_batches=4,
+        learning_rate=1.0e-3,
+        schedule="adaptive",
+        gamma=0.99,
+        lam=0.95,
+        desired_kl=0.01,
+        max_grad_norm=1.0,
+    )

source/isaaclab_tasks/isaaclab_tasks/manager_based/loco_manipulation/tracking/config/digit/loco_manip_env_cfg.py

+# Copyright (c) 2022-2025, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+import math
+
+from isaaclab_assets.robots.agility import ARM_JOINT_NAMES, LEG_JOINT_NAMES
+
+from isaaclab.managers import EventTermCfg
+from isaaclab.managers import ObservationGroupCfg as ObsGroup
+from isaaclab.managers import ObservationTermCfg as ObsTerm
+from isaaclab.managers import RewardTermCfg as RewTerm
+from isaaclab.managers import SceneEntityCfg
+from isaaclab.utils import configclass
+from isaaclab.utils.noise import AdditiveUniformNoiseCfg as Unoise
+
+import isaaclab_tasks.manager_based.locomotion.velocity.mdp as mdp
+import isaaclab_tasks.manager_based.manipulation.reach.mdp as manipulation_mdp
+from isaaclab_tasks.manager_based.locomotion.velocity.config.digit.rough_env_cfg import DigitRewards, DigitRoughEnvCfg
+from isaaclab_tasks.manager_based.locomotion.velocity.velocity_env_cfg import EventCfg
+
+
+@configclass
+class DigitLocoManipRewards(DigitRewards):
+    joint_deviation_arms = None
+
+    joint_vel_hip_yaw = RewTerm(
+        func=mdp.joint_vel_l2,
+        weight=-0.001,
+        params={"asset_cfg": SceneEntityCfg("robot", joint_names=[".*_leg_hip_yaw"])},
+    )
+
+    left_ee_pos_tracking = RewTerm(
+        func=manipulation_mdp.position_command_error,
+        weight=-2.0,
+        params={
+            "asset_cfg": SceneEntityCfg("robot", body_names="left_arm_wrist_yaw"),
+            "command_name": "left_ee_pose",
+        },
+    )
+
+    left_ee_pos_tracking_fine_grained = RewTerm(
+        func=manipulation_mdp.position_command_error_tanh,
+        weight=2.0,
+        params={
+            "asset_cfg": SceneEntityCfg("robot", body_names="left_arm_wrist_yaw"),
+            "std": 0.05,
+            "command_name": "left_ee_pose",
+        },
+    )
+
+    left_end_effector_orientation_tracking = RewTerm(
+        func=manipulation_mdp.orientation_command_error,
+        weight=-0.2,
+        params={
+            "asset_cfg": SceneEntityCfg("robot", body_names="left_arm_wrist_yaw"),
+            "command_name": "left_ee_pose",
+        },
+    )
+
+    right_ee_pos_tracking = RewTerm(
+        func=manipulation_mdp.position_command_error,
+        weight=-2.0,
+        params={
+            "asset_cfg": SceneEntityCfg("robot", body_names="right_arm_wrist_yaw"),
+            "command_name": "right_ee_pose",
+        },
+    )
+
+    right_ee_pos_tracking_fine_grained = RewTerm(
+        func=manipulation_mdp.position_command_error_tanh,
+        weight=2.0,
+        params={
+            "asset_cfg": SceneEntityCfg("robot", body_names="right_arm_wrist_yaw"),
+            "std": 0.05,
+            "command_name": "right_ee_pose",
+        },
+    )
+
+    right_end_effector_orientation_tracking = RewTerm(
+        func=manipulation_mdp.orientation_command_error,
+        weight=-0.2,
+        params={
+            "asset_cfg": SceneEntityCfg("robot", body_names="right_arm_wrist_yaw"),
+            "command_name": "right_ee_pose",
+        },
+    )
+
+
+@configclass
+class DigitLocoManipObservations:
+
+    @configclass
+    class PolicyCfg(ObsGroup):
+        base_lin_vel = ObsTerm(
+            func=mdp.base_lin_vel,
+            noise=Unoise(n_min=-0.1, n_max=0.1),
+        )
+        base_ang_vel = ObsTerm(
+            func=mdp.base_ang_vel,
+            noise=Unoise(n_min=-0.2, n_max=0.2),
+        )
+        projected_gravity = ObsTerm(
+            func=mdp.projected_gravity,
+            noise=Unoise(n_min=-0.05, n_max=0.05),
+        )
+        velocity_commands = ObsTerm(
+            func=mdp.generated_commands,
+            params={"command_name": "base_velocity"},
+        )
+        left_ee_pose_command = ObsTerm(
+            func=mdp.generated_commands,
+            params={"command_name": "left_ee_pose"},
+        )
+        right_ee_pose_command = ObsTerm(
+            func=mdp.generated_commands,
+            params={"command_name": "right_ee_pose"},
+        )
+        joint_pos = ObsTerm(
+            func=mdp.joint_pos_rel,
+            params={"asset_cfg": SceneEntityCfg("robot", joint_names=LEG_JOINT_NAMES + ARM_JOINT_NAMES)},
+            noise=Unoise(n_min=-0.01, n_max=0.01),
+        )
+        joint_vel = ObsTerm(
+            func=mdp.joint_vel_rel,
+            params={"asset_cfg": SceneEntityCfg("robot", joint_names=LEG_JOINT_NAMES + ARM_JOINT_NAMES)},
+            noise=Unoise(n_min=-1.5, n_max=1.5),
+        )
+        actions = ObsTerm(func=mdp.last_action)
+
+        def __post_init__(self):
+            self.enable_corruption = True
+            self.concatenate_terms = True
+
+    policy = PolicyCfg()
+
+
+@configclass
+class DigitLocoManipCommands:
+    base_velocity = mdp.UniformVelocityCommandCfg(
+        asset_name="robot",
+        resampling_time_range=(10.0, 10.0),
+        rel_standing_envs=0.25,
+        rel_heading_envs=1.0,
+        heading_command=True,
+        debug_vis=True,
+        ranges=mdp.UniformVelocityCommandCfg.Ranges(
+            lin_vel_x=(-1.0, 1.0),
+            lin_vel_y=(-1.0, 1.0),
+            ang_vel_z=(-1.0, 1.0),
+            heading=(-math.pi, math.pi),
+        ),
+    )
+
+    left_ee_pose = mdp.UniformPoseCommandCfg(
+        asset_name="robot",
+        body_name="left_arm_wrist_yaw",
+        resampling_time_range=(1.0, 3.0),
+        debug_vis=True,
+        ranges=mdp.UniformPoseCommandCfg.Ranges(
+            pos_x=(0.10, 0.50),
+            pos_y=(0.05, 0.50),
+            pos_z=(-0.20, 0.20),
+            roll=(-0.1, 0.1),
+            pitch=(-0.1, 0.1),
+            yaw=(math.pi / 2.0 - 0.1, math.pi / 2.0 + 0.1),
+        ),
+    )
+
+    right_ee_pose = mdp.UniformPoseCommandCfg(
+        asset_name="robot",
+        body_name="right_arm_wrist_yaw",
+        resampling_time_range=(1.0, 3.0),
+        debug_vis=True,
+        ranges=mdp.UniformPoseCommandCfg.Ranges(
+            pos_x=(0.10, 0.50),
+            pos_y=(-0.50, -0.05),
+            pos_z=(-0.20, 0.20),
+            roll=(-0.1, 0.1),
+            pitch=(-0.1, 0.1),
+            yaw=(-math.pi / 2.0 - 0.1, -math.pi / 2.0 + 0.1),
+        ),
+    )
+
+
+@configclass
+class DigitEvents(EventCfg):
+    # Add an external force to simulate a payload being carried.
+    left_hand_force = EventTermCfg(
+        func=mdp.apply_external_force_torque,
+        mode="interval",
+        interval_range_s=(10.0, 15.0),
+        params={
+            "asset_cfg": SceneEntityCfg("robot", body_names="left_arm_wrist_yaw"),
+            "force_range": (-10.0, 10.0),
+            "torque_range": (-1.0, 1.0),
+        },
+    )
+
+    right_hand_force = EventTermCfg(
+        func=mdp.apply_external_force_torque,
+        mode="interval",
+        interval_range_s=(10.0, 15.0),
+        params={
+            "asset_cfg": SceneEntityCfg("robot", body_names="right_arm_wrist_yaw"),
+            "force_range": (-10.0, 10.0),
+            "torque_range": (-1.0, 1.0),
+        },
+    )
+
+
+@configclass
+class DigitLocoManipEnvCfg(DigitRoughEnvCfg):
+    rewards: DigitLocoManipRewards = DigitLocoManipRewards()
+    observations: DigitLocoManipObservations = DigitLocoManipObservations()
+    commands: DigitLocoManipCommands = DigitLocoManipCommands()
+
+    def __post_init__(self):
+        super().__post_init__()
+
+        self.episode_length_s = 14.0
+
+        # Rewards:
+        self.rewards.flat_orientation_l2.weight = -10.5
+        self.rewards.termination_penalty.weight = -100.0
+
+        # Change terrain to flat.
+        self.scene.terrain.terrain_type = "plane"
+        self.scene.terrain.terrain_generator = None
+        # Remove height scanner.
+        self.scene.height_scanner = None
+        self.observations.policy.height_scan = None
+        # Remove terrain curriculum.
+        self.curriculum.terrain_levels = None
+
+
+class DigitLocoManipEnvCfg_PLAY(DigitLocoManipEnvCfg):
+
+    def __post_init__(self) -> None:
+        super().__post_init__()
+
+        # Make a smaller scene for play.
+        self.scene.num_envs = 50
+        self.scene.env_spacing = 2.5
+        # Disable randomization for play.
+        self.observations.policy.enable_corruption = False
+        # Remove random pushing.
+        self.randomization.base_external_force_torque = None
+        self.randomization.push_robot = None

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

@@ -46,6 +46,7 @@ class UnitreeA1RoughEnvCfg(LocomotionVelocityRoughEnvCfg):
                 "yaw": (0.0, 0.0),
             },
         }
+        self.events.base_com = None
 
         # rewards
         self.rewards.feet_air_time.params["sensor_cfg"].body_names = ".*_foot"
@@ -82,4 +83,3 @@ class UnitreeA1RoughEnvCfg_PLAY(UnitreeA1RoughEnvCfg):
         # remove random pushing event
         self.events.base_external_force_torque = None
         self.events.push_robot = None
-        self.events.base_com = None

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

@@ -77,6 +77,7 @@ class CassieRoughEnvCfg(LocomotionVelocityRoughEnvCfg):
                 "yaw": (0.0, 0.0),
             },
         }
+        self.events.base_com = None
 
         # terminations
         self.terminations.base_contact.params["sensor_cfg"].body_names = [".*pelvis"]
@@ -112,5 +113,3 @@ class CassieRoughEnvCfg_PLAY(CassieRoughEnvCfg):
         self.commands.base_velocity.ranges.heading = (0.0, 0.0)
         # disable randomization for play
         self.observations.policy.enable_corruption = False
-        # disable com randomization
-        self.events.base_com = None

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

+# Copyright (c) 2022-2025, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+import gymnasium as gym
+
+from . import agents
+
+##
+# Register Gym environments.
+##
+gym.register(
+    id="Isaac-Velocity-Flat-Digit-v0",
+    entry_point="isaaclab.envs:ManagerBasedRLEnv",
+    disable_env_checker=True,
+    kwargs={
+        "env_cfg_entry_point": f"{__name__}.flat_env_cfg:DigitFlatEnvCfg",
+        "rsl_rl_cfg_entry_point": f"{agents.__name__}.rsl_rl_ppo_cfg:DigitFlatPPORunnerCfg",
+    },
+)
+
+
+gym.register(
+    id="Isaac-Velocity-Flat-Digit-Play-v0",
+    entry_point="isaaclab.envs:ManagerBasedRLEnv",
+    disable_env_checker=True,
+    kwargs={
+        "env_cfg_entry_point": f"{__name__}.flat_env_cfg:DigitFlatEnvCfg_PLAY",
+        "rsl_rl_cfg_entry_point": f"{agents.__name__}.rsl_rl_ppo_cfg:DigitFlatPPORunnerCfg",
+    },
+)
+
+
+gym.register(
+    id="Isaac-Velocity-Rough-Digit-v0",
+    entry_point="isaaclab.envs:ManagerBasedRLEnv",
+    disable_env_checker=True,
+    kwargs={
+        "env_cfg_entry_point": f"{__name__}.rough_env_cfg:DigitRoughEnvCfg",
+        "rsl_rl_cfg_entry_point": f"{agents.__name__}.rsl_rl_ppo_cfg:DigitRoughPPORunnerCfg",
+    },
+)
+
+
+gym.register(
+    id="Isaac-Velocity-Rough-Digit-Play-v0",
+    entry_point="isaaclab.envs:ManagerBasedRLEnv",
+    disable_env_checker=True,
+    kwargs={
+        "env_cfg_entry_point": f"{__name__}.rough_env_cfg:DigitRoughEnvCfg_PLAY",
+        "rsl_rl_cfg_entry_point": f"{agents.__name__}.rsl_rl_ppo_cfg:DigitRoughPPORunnerCfg",
+    },
+)

source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/config/digit/agents/__init__.py

+# Copyright (c) 2022-2025, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause

source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/config/digit/agents/rsl_rl_ppo_cfg.py

+# Copyright (c) 2022-2025, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+from isaaclab.utils import configclass
+
+from isaaclab_rl.rsl_rl import RslRlOnPolicyRunnerCfg, RslRlPpoActorCriticCfg, RslRlPpoAlgorithmCfg
+
+
+@configclass
+class DigitRoughPPORunnerCfg(RslRlOnPolicyRunnerCfg):
+    num_steps_per_env = 24
+    max_iterations = 3000
+    save_interval = 50
+    experiment_name = "digit_rough"
+    empirical_normalization = False
+    policy = RslRlPpoActorCriticCfg(
+        init_noise_std=1.0,
+        actor_hidden_dims=[512, 256, 128],
+        critic_hidden_dims=[512, 256, 128],
+        activation="elu",
+    )
+    algorithm = RslRlPpoAlgorithmCfg(
+        value_loss_coef=1.0,
+        use_clipped_value_loss=True,
+        clip_param=0.2,
+        entropy_coef=0.01,
+        num_learning_epochs=5,
+        num_mini_batches=4,
+        learning_rate=1.0e-3,
+        schedule="adaptive",
+        gamma=0.99,
+        lam=0.95,
+        desired_kl=0.01,
+        max_grad_norm=1.0,
+    )
+
+
+@configclass
+class DigitFlatPPORunnerCfg(DigitRoughPPORunnerCfg):
+    def __post_init__(self):
+        super().__post_init__()
+
+        self.max_iterations = 2000
+        self.experiment_name = "digit_flat"
+
+        self.policy.actor_hidden_dims = [128, 128, 128]
+        self.policy.critic_hidden_dims = [128, 128, 128]

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

+# Copyright (c) 2022-2025, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+from isaaclab.utils import configclass
+
+from .rough_env_cfg import DigitRoughEnvCfg
+
+
+@configclass
+class DigitFlatEnvCfg(DigitRoughEnvCfg):
+    def __post_init__(self):
+        super().__post_init__()
+
+        # Change terrain to flat.
+        self.scene.terrain.terrain_type = "plane"
+        self.scene.terrain.terrain_generator = None
+        # Remove height scanner.
+        self.scene.height_scanner = None
+        self.observations.policy.height_scan = None
+        # Remove terrain curriculum.
+        self.curriculum.terrain_levels = None
+
+
+class DigitFlatEnvCfg_PLAY(DigitFlatEnvCfg):
+    def __post_init__(self) -> None:
+        super().__post_init__()
+
+        # Make a smaller scene for play.
+        self.scene.num_envs = 50
+        self.scene.env_spacing = 2.5
+        # Disable randomization for play.
+        self.observations.policy.enable_corruption = False
+        # Remove random pushing.
+        self.randomization.base_external_force_torque = None
+        self.randomization.push_robot = None

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

+# Copyright (c) 2022-2025, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+import math
+
+from isaaclab_assets.robots.agility import ARM_JOINT_NAMES, DIGIT_V4_CFG, LEG_JOINT_NAMES
+
+from isaaclab.managers import ObservationGroupCfg, ObservationTermCfg, RewardTermCfg, SceneEntityCfg, TerminationTermCfg
+from isaaclab.utils import configclass
+from isaaclab.utils.noise import AdditiveUniformNoiseCfg as Unoise
+
+import isaaclab_tasks.manager_based.locomotion.velocity.mdp as mdp
+from isaaclab_tasks.manager_based.locomotion.velocity.velocity_env_cfg import LocomotionVelocityRoughEnvCfg
+
+
+@configclass
+class DigitRewards:
+    termination_penalty = RewardTermCfg(
+        func=mdp.is_terminated,
+        weight=-100.0,
+    )
+    track_lin_vel_xy_exp = RewardTermCfg(
+        func=mdp.track_lin_vel_xy_yaw_frame_exp,
+        weight=1.0,
+        params={"command_name": "base_velocity", "std": math.sqrt(0.25)},
+    )
+    track_ang_vel_z_exp = RewardTermCfg(
+        func=mdp.track_ang_vel_z_world_exp,
+        weight=1.0,
+        params={
+            "command_name": "base_velocity",
+            "std": math.sqrt(0.25),
+        },
+    )
+    feet_air_time = RewardTermCfg(
+        func=mdp.feet_air_time_positive_biped,
+        weight=0.25,
+        params={
+            "sensor_cfg": SceneEntityCfg("contact_forces", body_names=".*_leg_toe_roll"),
+            "threshold": 0.8,
+            "command_name": "base_velocity",
+        },
+    )
+    feet_slide = RewardTermCfg(
+        func=mdp.feet_slide,
+        weight=-0.25,
+        params={
+            "sensor_cfg": SceneEntityCfg("contact_forces", body_names=".*_leg_toe_roll"),
+            "asset_cfg": SceneEntityCfg("robot", body_names=".*_leg_toe_roll"),
+        },
+    )
+    dof_torques_l2 = RewardTermCfg(
+        func=mdp.joint_torques_l2,
+        weight=-1.0e-6,
+    )
+    dof_acc_l2 = RewardTermCfg(
+        func=mdp.joint_acc_l2,
+        weight=-2.0e-7,
+        params={"asset_cfg": SceneEntityCfg("robot", joint_names=LEG_JOINT_NAMES + ARM_JOINT_NAMES)},
+    )
+    action_rate_l2 = RewardTermCfg(
+        func=mdp.action_rate_l2,
+        weight=-0.008,
+    )
+    flat_orientation_l2 = RewardTermCfg(
+        func=mdp.flat_orientation_l2,
+        weight=-2.5,
+    )
+    stand_still = RewardTermCfg(
+        func=mdp.stand_still_joint_deviation_l1,
+        weight=-0.4,
+        params={
+            "command_name": "base_velocity",
+            "asset_cfg": SceneEntityCfg("robot", joint_names=LEG_JOINT_NAMES),
+        },
+    )
+    lin_vel_z_l2 = RewardTermCfg(
+        func=mdp.lin_vel_z_l2,
+        weight=-2.0,
+    )
+    ang_vel_xy_l2 = RewardTermCfg(
+        func=mdp.ang_vel_xy_l2,
+        weight=-0.1,
+    )
+    no_jumps = RewardTermCfg(
+        func=mdp.desired_contacts,
+        weight=-0.5,
+        params={"sensor_cfg": SceneEntityCfg("contact_forces", body_names=[".*_leg_toe_roll"])},
+    )
+    dof_pos_limits = RewardTermCfg(
+        func=mdp.joint_pos_limits,
+        weight=-1.0,
+        params={"asset_cfg": SceneEntityCfg("robot", joint_names=[".*_leg_toe_roll", ".*_leg_toe_pitch", ".*_tarsus"])},
+    )
+    joint_deviation_hip_roll = RewardTermCfg(
+        func=mdp.joint_deviation_l1,
+        weight=-0.1,
+        params={"asset_cfg": SceneEntityCfg("robot", joint_names=".*_leg_hip_roll")},
+    )
+    joint_deviation_hip_yaw = RewardTermCfg(
+        func=mdp.joint_deviation_l1,
+        weight=-0.2,
+        params={"asset_cfg": SceneEntityCfg("robot", joint_names=".*_leg_hip_yaw")},
+    )
+    joint_deviation_knee = RewardTermCfg(
+        func=mdp.joint_deviation_l1,
+        weight=-0.2,
+        params={"asset_cfg": SceneEntityCfg("robot", joint_names=".*_tarsus")},
+    )
+    joint_deviation_feet = RewardTermCfg(
+        func=mdp.joint_deviation_l1,
+        weight=-0.1,
+        params={"asset_cfg": SceneEntityCfg("robot", joint_names=[".*_toe_a", ".*_toe_b"])},
+    )
+    joint_deviation_arms = RewardTermCfg(
+        func=mdp.joint_deviation_l1,
+        weight=-0.2,
+        params={
+            "asset_cfg": SceneEntityCfg("robot", joint_names=".*_arm_.*"),
+        },
+    )
+
+    undesired_contacts = RewardTermCfg(
+        func=mdp.undesired_contacts,
+        weight=-0.1,
+        params={
+            "sensor_cfg": SceneEntityCfg("contact_forces", body_names=[".*_rod", ".*_tarsus"]),
+            "threshold": 1.0,
+        },
+    )
+
+
+@configclass
+class DigitObservations:
+    @configclass
+    class PolicyCfg(ObservationGroupCfg):
+        base_lin_vel = ObservationTermCfg(
+            func=mdp.base_lin_vel,
+            noise=Unoise(n_min=-0.1, n_max=0.1),
+        )
+        base_ang_vel = ObservationTermCfg(
+            func=mdp.base_ang_vel,
+            noise=Unoise(n_min=-0.2, n_max=0.2),
+        )
+        projected_gravity = ObservationTermCfg(
+            func=mdp.projected_gravity,
+            noise=Unoise(n_min=-0.05, n_max=0.05),
+        )
+        velocity_commands = ObservationTermCfg(
+            func=mdp.generated_commands,
+            params={"command_name": "base_velocity"},
+        )
+        joint_pos = ObservationTermCfg(
+            func=mdp.joint_pos_rel,
+            params={"asset_cfg": SceneEntityCfg("robot", joint_names=LEG_JOINT_NAMES + ARM_JOINT_NAMES)},
+            noise=Unoise(n_min=-0.01, n_max=0.01),
+        )
+        joint_vel = ObservationTermCfg(
+            func=mdp.joint_vel_rel,
+            params={"asset_cfg": SceneEntityCfg("robot", joint_names=LEG_JOINT_NAMES + ARM_JOINT_NAMES)},
+            noise=Unoise(n_min=-1.5, n_max=1.5),
+        )
+        actions = ObservationTermCfg(func=mdp.last_action)
+        height_scan = ObservationTermCfg(
+            func=mdp.height_scan,
+            params={"sensor_cfg": SceneEntityCfg("height_scanner")},
+            noise=Unoise(n_min=-0.1, n_max=0.1),
+            clip=(-1.0, 1.0),
+        )
+
+        def __post_init__(self):
+            self.enable_corruption = True
+            self.concatenate_terms = True
+
+    # Observation groups:
+    policy: PolicyCfg = PolicyCfg()
+
+
+@configclass
+class TerminationsCfg:
+    """Termination terms for the MDP."""
+
+    time_out = TerminationTermCfg(func=mdp.time_out, time_out=True)
+    base_contact = TerminationTermCfg(
+        func=mdp.illegal_contact,
+        params={
+            "sensor_cfg": SceneEntityCfg("contact_forces", body_names=["torso_base"]),
+            "threshold": 1.0,
+        },
+    )
+    base_orientation = TerminationTermCfg(
+        func=mdp.bad_orientation,
+        params={"limit_angle": 0.7},
+    )
+
+
+@configclass
+class ActionsCfg:
+    """Action specifications for the MDP."""
+
+    joint_pos = mdp.JointPositionActionCfg(
+        asset_name="robot",
+        joint_names=LEG_JOINT_NAMES + ARM_JOINT_NAMES,
+        scale=0.5,
+        use_default_offset=True,
+    )
+
+
+@configclass
+class DigitRoughEnvCfg(LocomotionVelocityRoughEnvCfg):
+    rewards: DigitRewards = DigitRewards()
+    observations: DigitObservations = DigitObservations()
+    terminations: TerminationsCfg = TerminationsCfg()
+    actions: ActionsCfg = ActionsCfg()
+
+    def __post_init__(self):
+        super().__post_init__()
+        self.decimation = 4
+        self.sim.dt = 0.005
+
+        # Scene
+        self.scene.robot = DIGIT_V4_CFG.replace(prim_path="{ENV_REGEX_NS}/Robot")
+        self.scene.height_scanner.prim_path = "{ENV_REGEX_NS}/Robot/torso_base"
+        self.scene.contact_forces.history_length = self.decimation
+        self.scene.contact_forces.update_period = self.sim.dt
+        self.scene.height_scanner.update_period = self.decimation * self.sim.dt
+
+        # Events:
+        self.events.add_base_mass.params["asset_cfg"] = SceneEntityCfg("robot", body_names="torso_base")
+        self.events.base_external_force_torque.params["asset_cfg"] = SceneEntityCfg("robot", body_names="torso_base")
+        # Don't randomize the initial joint positions because we have closed loops.
+        self.events.reset_robot_joints.params["position_range"] = (1.0, 1.0)
+        # remove COM randomization
+        self.events.base_com = None
+
+        # Commands
+        self.commands.base_velocity.ranges.lin_vel_x = (-0.8, 0.8)
+        self.commands.base_velocity.ranges.lin_vel_y = (-0.5, 0.5)
+        self.commands.base_velocity.ranges.ang_vel_z = (-1.0, 1.0)
+        self.commands.base_velocity.rel_standing_envs = 0.1
+        self.commands.base_velocity.resampling_time_range = (3.0, 8.0)
+
+
+@configclass
+class DigitRoughEnvCfg_PLAY(DigitRoughEnvCfg):
+    def __post_init__(self):
+        super().__post_init__()
+
+        # Make a smaller scene for play.
+        self.scene.num_envs = 50
+        self.scene.env_spacing = 2.5
+        # Spawn the robot randomly in the grid (instead of their terrain levels).
+        self.scene.terrain.max_init_terrain_level = None
+        # Reduce the number of terrains to save memory.
+        if self.scene.terrain.terrain_generator is not None:
+            self.scene.terrain.terrain_generator.num_rows = 5
+            self.scene.terrain.terrain_generator.num_cols = 5
+            self.scene.terrain.terrain_generator.curriculum = False
+
+        # Disable randomization for play.
+        self.observations.policy.enable_corruption = False
+        # Remove random pushing.
+        self.randomization.base_external_force_torque = None
+        self.randomization.push_robot = None

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

@@ -127,6 +127,7 @@ class G1RoughEnvCfg(LocomotionVelocityRoughEnvCfg):
                 "yaw": (0.0, 0.0),
             },
         }
+        self.events.base_com = None
 
         # Rewards
         self.rewards.lin_vel_z_l2.weight = 0.0
@@ -178,4 +179,3 @@ class G1RoughEnvCfg_PLAY(G1RoughEnvCfg):
         # remove random pushing
         self.events.base_external_force_torque = None
         self.events.push_robot = None
-        self.events.base_com = None

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

@@ -46,6 +46,7 @@ class UnitreeGo1RoughEnvCfg(LocomotionVelocityRoughEnvCfg):
                 "yaw": (0.0, 0.0),
             },
         }
+        self.events.base_com = None
 
         # rewards
         self.rewards.feet_air_time.params["sensor_cfg"].body_names = ".*_foot"
@@ -82,4 +83,3 @@ class UnitreeGo1RoughEnvCfg_PLAY(UnitreeGo1RoughEnvCfg):
         # remove random pushing event
         self.events.base_external_force_torque = None
         self.events.push_robot = None
-        self.events.base_com = None

source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/config/go2/rough_env_cfg.py

@@ -46,6 +46,7 @@ class UnitreeGo2RoughEnvCfg(LocomotionVelocityRoughEnvCfg):
                 "yaw": (0.0, 0.0),
             },
         }
+        self.events.base_com = None
 
         # rewards
         self.rewards.feet_air_time.params["sensor_cfg"].body_names = ".*_foot"
@@ -82,4 +83,3 @@ class UnitreeGo2RoughEnvCfg_PLAY(UnitreeGo2RoughEnvCfg):
         # remove random pushing event
         self.events.base_external_force_torque = None
         self.events.push_robot = None
-        self.events.base_com = None

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

@@ -95,6 +95,7 @@ class H1RoughEnvCfg(LocomotionVelocityRoughEnvCfg):
                 "yaw": (0.0, 0.0),
             },
         }
+        self.events.base_com = None
 
         # Terminations
         self.terminations.base_contact.params["sensor_cfg"].body_names = [".*torso_link"]
@@ -142,4 +143,3 @@ class H1RoughEnvCfg_PLAY(H1RoughEnvCfg):
         # remove random pushing
         self.events.base_external_force_torque = None
         self.events.push_robot = None
-        self.events.base_com = None

source/isaaclab_tasks/isaaclab_tasks/manager_based/locomotion/velocity/mdp/rewards.py

@@ -14,6 +14,7 @@ from __future__ import annotations
 import torch
 from typing import TYPE_CHECKING
 
+from isaaclab.envs import mdp
 from isaaclab.managers import SceneEntityCfg
 from isaaclab.sensors import ContactSensor
 from isaaclab.utils.math import quat_apply_inverse, yaw_quat
@@ -104,3 +105,12 @@ def track_ang_vel_z_world_exp(
     asset = env.scene[asset_cfg.name]
     ang_vel_error = torch.square(env.command_manager.get_command(command_name)[:, 2] - asset.data.root_ang_vel_w[:, 2])
     return torch.exp(-ang_vel_error / std**2)
+
+
+def stand_still_joint_deviation_l1(
+    env, command_name: str, command_threshold: float = 0.06, asset_cfg: SceneEntityCfg = SceneEntityCfg("robot")
+) -> torch.Tensor:
+    """Penalize offsets from the default joint positions when the command is very small."""
+    command = env.command_manager.get_command(command_name)
+    # Penalize motion when command is nearly zero.
+    return mdp.joint_deviation_l1(env, asset_cfg) * (torch.norm(command[:, :2], dim=1) < command_threshold)