add go2 articulation cfg from unitree_rl_lab; align domain rand with go2_rl_gym.

source/robot_lab/robot_lab/assets/unitree.py

@@ -5,17 +5,71 @@
 Reference: https://github.com/unitreerobotics/unitree_ros
 """
 
+import os
 import isaaclab.sim as sim_utils
 from isaaclab.actuators import DCMotorCfg
 from isaaclab.assets.articulation import ArticulationCfg
+from isaaclab.utils import configclass
 
 from robot_lab.assets import ISAACLAB_ASSETS_DATA_DIR
+from robot_lab.assets.unitree_actuator import UnitreeActuatorCfg_Go2HV
 
 ##
 # Configuration
 ##
+@configclass
+class UnitreeArticulationCfg(ArticulationCfg):
+    """Configuration for Unitree articulations."""
 
-UNITREE_GO2_CFG = ArticulationCfg(
+    joint_sdk_names: list[str] = None
+
+    soft_joint_pos_limit_factor = 0.9
+
+
+@configclass
+class UnitreeUrdfFileCfg(sim_utils.UrdfFileCfg):
+    fix_base: bool = False
+    activate_contact_sensors: bool = True
+    replace_cylinders_with_capsules = True
+    joint_drive = sim_utils.UrdfConverterCfg.JointDriveCfg(
+        gains=sim_utils.UrdfConverterCfg.JointDriveCfg.PDGainsCfg(stiffness=0, damping=0)
+    )
+    articulation_props = sim_utils.ArticulationRootPropertiesCfg(
+        enabled_self_collisions=True,
+        solver_position_iteration_count=8,
+        solver_velocity_iteration_count=4,
+    )
+    rigid_props = sim_utils.RigidBodyPropertiesCfg(
+        disable_gravity=False,
+        retain_accelerations=False,
+        linear_damping=0.0,
+        angular_damping=0.0,
+        max_linear_velocity=1000.0,
+        max_angular_velocity=1000.0,
+        max_depenetration_velocity=1.0,
+    )
+
+    def replace_asset(self, meshes_dir, urdf_path):
+        """Replace the asset with a temporary copy to avoid modifying the original asset.
+
+        When need to change the collisions, place the modified URDF file separately in this repository,
+        and let `meshes_dir` be provided by `unitree_ros`.
+        This function will auto construct a complete `robot_description` file structure in the `/tmp` directory.
+        Note: The mesh references inside the URDF should be in the same directory level as the URDF itself.
+        """
+        tmp_meshes_dir = "/tmp/IsaacLab/unitree_rl_lab/meshes"
+        if os.path.exists(tmp_meshes_dir):
+            os.remove(tmp_meshes_dir)
+        os.makedirs("/tmp/IsaacLab/unitree_rl_lab", exist_ok=True)
+        os.symlink(meshes_dir, tmp_meshes_dir)
+
+        self.asset_path = "/tmp/IsaacLab/unitree_rl_lab/robot.urdf"
+        if os.path.exists(self.asset_path):
+            os.remove(self.asset_path)
+        os.symlink(urdf_path, self.asset_path)
+
+# Go2 config from robot_lab [https://github.com/fan-ziqi/robot_lab]
+GO2_CFG_ROBOTLAB = ArticulationCfg(
     spawn=sim_utils.UrdfFileCfg(
         fix_base=False,
         merge_fixed_joints=True,
@@ -66,5 +120,39 @@ UNITREE_GO2_CFG = ArticulationCfg(
         ),
     },
 )
-"""Configuration of Unitree Go2 using DC motor.
-"""
+
+
+
+# Go2 config from unitree_rl_lab [https://github.com/unitreerobotics/unitree_rl_lab]
+GO2_CFG_UNITREE = UnitreeArticulationCfg(
+    spawn=UnitreeUrdfFileCfg(
+        asset_path=f"{ISAACLAB_ASSETS_DATA_DIR}/go2/urdf/go2.urdf",
+    ),
+    init_state=ArticulationCfg.InitialStateCfg(
+        pos=(0.0, 0.0, 0.4),
+        joint_pos={
+            ".*R_hip_joint": -0.1,
+            ".*L_hip_joint": 0.1,
+            "F[L,R]_thigh_joint": 0.8,
+            "R[L,R]_thigh_joint": 1.0,
+            ".*_calf_joint": -1.5,
+        },
+        joint_vel={".*": 0.0},
+    ),
+    actuators={
+        "GO2HV": UnitreeActuatorCfg_Go2HV(
+            joint_names_expr=[".*"],
+            stiffness=25.0,
+            damping=0.5,
+            friction=0.01,
+        ),
+    },
+    # fmt: off
+    joint_sdk_names=[
+        "FR_hip_joint", "FR_thigh_joint", "FR_calf_joint",
+        "FL_hip_joint", "FL_thigh_joint", "FL_calf_joint",
+        "RR_hip_joint", "RR_thigh_joint", "RR_calf_joint",
+        "RL_hip_joint", "RL_thigh_joint", "RL_calf_joint"
+    ],
+    # fmt: on
+)

source/robot_lab/robot_lab/assets/unitree_actuator.py

@@ -0,0 +1,130 @@
+# Unitree actuator class that implements a torque-speed curve for the actuators.
+# source: https://github.com/unitreerobotics/unitree_rl_lab
+
+from __future__ import annotations
+
+import torch
+from dataclasses import MISSING
+
+from isaaclab.actuators import DelayedPDActuator, DelayedPDActuatorCfg
+from isaaclab.utils import configclass
+from isaaclab.utils.types import ArticulationActions
+
+
+class UnitreeActuator(DelayedPDActuator):
+    """Unitree actuator class that implements a torque-speed curve for the actuators.
+
+    The torque-speed curve is defined as follows:
+
+            Torque Limit, N·m
+                ^
+    Y2──────────|
+                |──────────────Y1
+                |              │\
+                |              │ \
+                |              │  \
+                |              |   \
+    ------------+--------------|------> velocity: rad/s
+                              X1   X2
+
+    - Y1: Peak Torque Test (Torque and Speed in the Same Direction)
+    - Y2: Peak Torque Test (Torque and Speed in the Opposite Direction)
+    - X1: Maximum Speed at Full Torque (T-N Curve Knee Point)
+    - X2: No-Load Speed Test
+
+    - Fs: Static friction coefficient
+    - Fd: Dynamic friction coefficient
+    - Va: Velocity at which the friction is fully activated
+    """
+
+    cfg: UnitreeActuatorCfg
+
+    armature: torch.Tensor
+    """The armature of the actuator joints. Shape is (num_envs, num_joints).
+        armature = J2 + J1 * i2 ^ 2 + Jr * (i1 * i2) ^ 2
+    """
+
+    def __init__(self, cfg: UnitreeActuatorCfg, *args, **kwargs):
+        super().__init__(cfg, *args, **kwargs)
+
+        self._joint_vel = torch.zeros_like(self.computed_effort)
+        self._effort_y1 = self._parse_joint_parameter(cfg.Y1, 1e9)
+        self._effort_y2 = self._parse_joint_parameter(cfg.Y2, cfg.Y1)
+        self._velocity_x1 = self._parse_joint_parameter(cfg.X1, 1e9)
+        self._velocity_x2 = self._parse_joint_parameter(cfg.X2, 1e9)
+        self._friction_static = self._parse_joint_parameter(cfg.Fs, 0.0)
+        self._friction_dynamic = self._parse_joint_parameter(cfg.Fd, 0.0)
+        self._activation_vel = self._parse_joint_parameter(cfg.Va, 0.01)
+
+    def compute(
+        self, control_action: ArticulationActions, joint_pos: torch.Tensor, joint_vel: torch.Tensor
+    ) -> ArticulationActions:
+        # save current joint vel
+        self._joint_vel[:] = joint_vel
+        # calculate the desired joint torques
+        control_action = super().compute(control_action, joint_pos, joint_vel)
+
+        # apply friction model on the torque
+        self.applied_effort -= (
+            self._friction_static * torch.tanh(joint_vel / self._activation_vel) + self._friction_dynamic * joint_vel
+        )
+
+        control_action.joint_positions = None
+        control_action.joint_velocities = None
+        control_action.joint_efforts = self.applied_effort
+
+        return control_action
+
+    def _clip_effort(self, effort: torch.Tensor) -> torch.Tensor:
+        # check if the effort is the same direction as the joint velocity
+        same_direction = (self._joint_vel * effort) > 0
+        max_effort = torch.where(same_direction, self._effort_y1, self._effort_y2)
+        # check if the joint velocity is less than the max speed at full torque
+        max_effort = torch.where(
+            self._joint_vel.abs() < self._velocity_x1, max_effort, self._compute_effort_limit(max_effort)
+        )
+        return torch.clip(effort, -max_effort, max_effort)
+
+    def _compute_effort_limit(self, max_effort):
+        k = -max_effort / (self._velocity_x2 - self._velocity_x1)
+        limit = k * (self._joint_vel.abs() - self._velocity_x1) + max_effort
+        return limit.clip(min=0.0)
+
+
+@configclass
+class UnitreeActuatorCfg(DelayedPDActuatorCfg):
+    """
+    Configuration for Unitree actuators.
+    """
+
+    class_type: type = UnitreeActuator
+
+    X1: float = 1e9
+    """Maximum Speed at Full Torque(T-N Curve Knee Point) Unit: rad/s"""
+
+    X2: float = 1e9
+    """No-Load Speed Test Unit: rad/s"""
+
+    Y1: float = MISSING
+    """Peak Torque Test(Torque and Speed in the Same Direction) Unit: N*m"""
+
+    Y2: float | None = None
+    """Peak Torque Test(Torque and Speed in the Opposite Direction) Unit: N*m"""
+
+    Fs: float = 0.0
+    """ Static friction coefficient """
+
+    Fd: float = 0.0
+    """ Dynamic friction coefficient """
+
+    Va: float = 0.01
+    """ Velocity at which the friction is fully activated """
+
+
+@configclass
+class UnitreeActuatorCfg_Go2HV(UnitreeActuatorCfg):
+    X1 = 13.5
+    X2 = 30
+    Y1 = 20.2
+    Y2 = 23.4
+

source/robot_lab/robot_lab/tasks/go2/env_cfg.py

@@ -18,7 +18,7 @@ from isaaclab.utils.noise import AdditiveUniformNoiseCfg as Unoise
 import isaaclab.terrains as terrain_gen
 
 import robot_lab.tasks.go2.mdp as mdp
-from robot_lab.assets.unitree import UNITREE_GO2_CFG
+from robot_lab.assets.unitree import GO2_CFG_ROBOTLAB, GO2_CFG_UNITREE
 
 JOINT_NAMES = [
     "FL_hip_joint", "FL_thigh_joint", "FL_calf_joint",
@@ -105,7 +105,7 @@ class Go2SceneCfg(InteractiveSceneCfg):
         debug_vis=False
     )
 
-    robot: ArticulationCfg = UNITREE_GO2_CFG.replace(prim_path="{ENV_REGEX_NS}/Robot")
+    robot: ArticulationCfg = GO2_CFG_ROBOTLAB.replace(prim_path="{ENV_REGEX_NS}/Robot")
 
     height_scanner = RayCasterCfg(
         prim_path="{ENV_REGEX_NS}/Robot/base",
@@ -331,7 +331,7 @@ class EventCfg:
         func=mdp.reset_joints_by_scale,
         mode="reset",
         params={
-            "position_range": (0.8, 1.2),
+            "position_range": (0.5, 1.5),
             "velocity_range": (0.0, 0.0),
         },
     )
@@ -387,15 +387,7 @@ class EventCfg:
             },
         },
     )
-    randomize_apply_external_force_torque = EventTerm(
-        func=mdp.apply_external_force_torque,
-        mode="reset",
-        params={
-            "asset_cfg": SceneEntityCfg("robot", body_names=BASE_LINK_NAME),
-            "force_range": (-5.0, 5.0),
-            "torque_range": (-5.0, 5.0),
-        },
-    )
+
         
 @configclass
 class RewardsCfg: