[Question] UR3e + Robotiq_2F_140_physics_edit : Pick and Place task

[sandokim]

Hello I assembled ur3e + Robotiq_2F_140_physics_edit(ur3e_gripper.zip) and tried to perfrom pick and place task with it.

I configured manager-based workflow for it and sucessfully launch isaaclab to do demo with it. But the problem here is when I move my ur3e+gripper to pick and place cube in the environment, the gripper is rotating further when the gripper grap the cube.

Is there any recommendation for solving this problem? I upload the code and usd file that I used!

C:/IsaacLab/source/isaaclab_assets/isaaclab_assets/robots/universal_robots.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


"""Configuration for the Universal Robots.

The following configuration parameters are available:

* :obj:`UR10_CFG`: The UR10 arm without a gripper.
* :obj:`UR10E_ROBOTIQ_GRIPPER_CFG`: The UR10E arm with Robotiq_2f_140 gripper.
* :obj:`UR3e_CFG`: The UR3e arm without a gripper.
* :obj:`UR3e_GRIPPER_CFG`: The UR3e arm with Robotiq_2F_140_physics_edit gripper.
* :obj:`UR3e_SHORT_SUCTION_CFG`: The UR3e arm with short suction gripper.

Reference: https://github.com/ros-industrial/universal_robot
"""

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, ISAACLAB_NUCLEUS_DIR

##
# Configuration
##

UR10_CFG = ArticulationCfg(
    spawn=sim_utils.UsdFileCfg(
        usd_path=f"{ISAACLAB_NUCLEUS_DIR}/Robots/UniversalRobots/UR10/ur10_instanceable.usd",
        rigid_props=sim_utils.RigidBodyPropertiesCfg(
            disable_gravity=False,
            max_depenetration_velocity=5.0,
        ),
        activate_contact_sensors=False,
    ),
    init_state=ArticulationCfg.InitialStateCfg(
        joint_pos={
            "shoulder_pan_joint": 0.0,
            "shoulder_lift_joint": -1.712,
            "elbow_joint": 1.712,
            "wrist_1_joint": 0.0,
            "wrist_2_joint": 0.0,
            "wrist_3_joint": 0.0,
        },
    ),
    actuators={
        "arm": ImplicitActuatorCfg(
            joint_names_expr=[".*"],
            effort_limit_sim=87.0,
            stiffness=800.0,
            damping=40.0,
        ),
    },
)

UR10e_CFG = ArticulationCfg(
    spawn=sim_utils.UsdFileCfg(
        usd_path=f"{ISAAC_NUCLEUS_DIR}/Robots/UniversalRobots/ur10e/ur10e.usd",
        rigid_props=sim_utils.RigidBodyPropertiesCfg(
            disable_gravity=True,
            max_depenetration_velocity=5.0,
        ),
        articulation_props=sim_utils.ArticulationRootPropertiesCfg(
            enabled_self_collisions=False, solver_position_iteration_count=16, solver_velocity_iteration_count=1
        ),
        activate_contact_sensors=False,
    ),
    init_state=ArticulationCfg.InitialStateCfg(
        joint_pos={
            "shoulder_pan_joint": 3.141592653589793,
            "shoulder_lift_joint": -1.5707963267948966,
            "elbow_joint": 1.5707963267948966,
            "wrist_1_joint": -1.5707963267948966,
            "wrist_2_joint": -1.5707963267948966,
            "wrist_3_joint": 0.0,
        },
        pos=(0.0, 0.0, 0.0),
        rot=(1.0, 0.0, 0.0, 0.0),
    ),
    actuators={
        # 'shoulder_pan_joint', 'shoulder_lift_joint', 'elbow_joint', 'wrist_1_joint', 'wrist_2_joint', 'wrist_3_joint'
        "shoulder": ImplicitActuatorCfg(
            joint_names_expr=["shoulder_.*"],
            stiffness=1320.0,
            damping=72.6636085,
            friction=0.0,
            armature=0.0,
        ),
        "elbow": ImplicitActuatorCfg(
            joint_names_expr=["elbow_joint"],
            stiffness=600.0,
            damping=34.64101615,
            friction=0.0,
            armature=0.0,
        ),
        "wrist": ImplicitActuatorCfg(
            joint_names_expr=["wrist_.*"],
            stiffness=216.0,
            damping=29.39387691,
            friction=0.0,
            armature=0.0,
        ),
    },
)

"""Configuration of UR-10 arm using implicit actuator models."""

UR10_LONG_SUCTION_CFG = UR10_CFG.copy()
UR10_LONG_SUCTION_CFG.spawn.usd_path = f"{ISAAC_NUCLEUS_DIR}/Robots/UniversalRobots/ur10/ur10.usd"
UR10_LONG_SUCTION_CFG.spawn.variants = {"Gripper": "Long_Suction"}
UR10_LONG_SUCTION_CFG.spawn.rigid_props.disable_gravity = True
UR10_LONG_SUCTION_CFG.init_state.joint_pos = {
    "shoulder_pan_joint": 0.0,
    "shoulder_lift_joint": -1.5707,
    "elbow_joint": 1.5707,
    "wrist_1_joint": -1.5707,
    "wrist_2_joint": 1.5707,
    "wrist_3_joint": 0.0,
}

"""Configuration of UR10 arm with long suction gripper."""

UR10_SHORT_SUCTION_CFG = UR10_LONG_SUCTION_CFG.copy()
UR10_SHORT_SUCTION_CFG.spawn.variants = {"Gripper": "Short_Suction"}

"""Configuration of UR10 arm with short suction gripper."""

UR10e_ROBOTIQ_GRIPPER_CFG = UR10e_CFG.copy()
UR10e_ROBOTIQ_GRIPPER_CFG.spawn.variants = {"Gripper": "Robotiq_2f_140"}
UR10e_ROBOTIQ_GRIPPER_CFG.spawn.rigid_props.disable_gravity = True
UR10e_ROBOTIQ_GRIPPER_CFG.init_state.joint_pos["finger_joint"] = 0.0
UR10e_ROBOTIQ_GRIPPER_CFG.init_state.joint_pos[".*_inner_finger_joint"] = 0.0
UR10e_ROBOTIQ_GRIPPER_CFG.init_state.joint_pos[".*_inner_finger_pad_joint"] = 0.0
UR10e_ROBOTIQ_GRIPPER_CFG.init_state.joint_pos[".*_outer_.*_joint"] = 0.0
# the major actuator joint for gripper
UR10e_ROBOTIQ_GRIPPER_CFG.actuators["gripper_drive"] = ImplicitActuatorCfg(
    joint_names_expr=["finger_joint"],
    effort_limit_sim=10.0,
    velocity_limit_sim=1.0,
    stiffness=11.25,
    damping=0.1,
    friction=0.0,
    armature=0.0,
)
# the auxiliary actuator joint for gripper
UR10e_ROBOTIQ_GRIPPER_CFG.actuators["gripper_finger"] = ImplicitActuatorCfg(
    joint_names_expr=[".*_inner_finger_joint"],
    effort_limit_sim=1.0,
    velocity_limit_sim=1.0,
    stiffness=0.2,
    damping=0.001,
    friction=0.0,
    armature=0.0,
)
# the passive joints for gripper
UR10e_ROBOTIQ_GRIPPER_CFG.actuators["gripper_passive"] = ImplicitActuatorCfg(
    joint_names_expr=[".*_inner_finger_pad_joint", ".*_outer_finger_joint", "right_outer_knuckle_joint"],
    effort_limit_sim=1.0,
    velocity_limit_sim=1.0,
    stiffness=0.0,
    damping=0.0,
    friction=0.0,
    armature=0.0,
)

"""Configuration of UR-10E arm with Robotiq_2f_140 gripper."""

UR3e_CFG = ArticulationCfg(
    spawn=sim_utils.UsdFileCfg(
        usd_path=r"C:\isaacsim_assets\isaac-sim-assets-robots_and_sensors-5.0.0\Assets\Isaac\5.0\Isaac\Robots\UniversalRobots\ur3e\ur3e_gripper.usd",
        rigid_props=sim_utils.RigidBodyPropertiesCfg(
            disable_gravity=True,
            max_depenetration_velocity=5.0,
        ),
        articulation_props=sim_utils.ArticulationRootPropertiesCfg(
            enabled_self_collisions=False, solver_position_iteration_count=64, solver_velocity_iteration_count=16
        ),
        activate_contact_sensors=False,
    ),
    init_state=ArticulationCfg.InitialStateCfg(
        joint_pos={
            "shoulder_pan_joint": 3.141592653589793,
            "shoulder_lift_joint": -1.5707963267948966,
            "elbow_joint": 1.5707963267948966,
            "wrist_1_joint": -1.5707963267948966,
            "wrist_2_joint": -1.5707963267948966,
            "wrist_3_joint": 0.0,
        },
        pos=(0.0, 0.0, 0.0),
        rot=(1.0, 0.0, 0.0, 0.0),
    ),
    actuators={
        # 'shoulder_pan_joint', 'shoulder_lift_joint', 'elbow_joint', 'wrist_1_joint', 'wrist_2_joint', 'wrist_3_joint'
        "shoulder": ImplicitActuatorCfg(
            joint_names_expr=["shoulder_.*"],
            stiffness=1320.0,
            damping=72.6636085,
            friction=0.0,
            armature=0.0,
        ),
        "elbow": ImplicitActuatorCfg(
            joint_names_expr=["elbow_joint"],
            stiffness=600.0,
            damping=34.64101615,
            friction=0.0,
            armature=0.0,
        ),
        "wrist": ImplicitActuatorCfg(
            joint_names_expr=["wrist_.*"],
            stiffness=216.0,
            damping=29.39387691,
            friction=0.0,
            armature=0.0,
        ),
    },
)

"""Configuration of UR-3e arm using implicit actuator models."""

UR3e_CFG = UR3e_CFG.copy()
UR3e_CFG.spawn.usd_path = r"C:\isaacsim_assets\isaac-sim-assets-robots_and_sensors-5.0.0\Assets\Isaac\5.0\Isaac\Robots\UniversalRobots\ur3e\ur3e_gripper.usd"
UR3e_CFG.spawn.variants = {"Gripper": "None"}
UR3e_CFG.spawn.rigid_props.disable_gravity = True
UR3e_CFG.init_state.joint_pos = {
    "shoulder_pan_joint": 0.0,
    "shoulder_lift_joint": -1.5707,
    "elbow_joint": 1.5707,
    "wrist_1_joint": -1.5707,
    "wrist_2_joint": 1.5707,
    "wrist_3_joint": 0.0,
}

"""Configuration of UR3e arm with Robotiq_2F_140_physics_edit gripper."""

UR3e_ROBOTIQ_GRIPPER_CFG = UR3e_CFG.copy()
UR3e_ROBOTIQ_GRIPPER_CFG.spawn.variants = {"Gripper": "Robotiq_2F_140_physics_edit"}
UR3e_ROBOTIQ_GRIPPER_CFG.spawn.rigid_props.disable_gravity = True
UR3e_ROBOTIQ_GRIPPER_CFG.init_state.joint_pos["finger_joint"] = 0.0
UR3e_ROBOTIQ_GRIPPER_CFG.init_state.joint_pos[".*_inner_finger_joint"] = 0.0
UR3e_ROBOTIQ_GRIPPER_CFG.init_state.joint_pos[".*_inner_finger_pad_joint"] = 0.0
UR3e_ROBOTIQ_GRIPPER_CFG.init_state.joint_pos[".*_outer_.*_joint"] = 0.0
# the major actuator joint for gripper
UR3e_ROBOTIQ_GRIPPER_CFG.actuators["gripper_drive"] = ImplicitActuatorCfg(
    joint_names_expr=["finger_joint"],
    effort_limit_sim=10.0,
    velocity_limit_sim=1.0,
    stiffness=11.25,
    damping=0.1,
    friction=0.0,
    armature=0.0,
)
# the auxiliary actuator joint for gripper
UR3e_ROBOTIQ_GRIPPER_CFG.actuators["gripper_finger"] = ImplicitActuatorCfg(
    joint_names_expr=[".*_inner_finger_joint"],
    effort_limit_sim=1.0,
    velocity_limit_sim=1.0,
    stiffness=0.2,
    damping=0.001,
    friction=0.0,
    armature=0.0,
)
# the passive joints for gripper
UR3e_ROBOTIQ_GRIPPER_CFG.actuators["gripper_passive"] = ImplicitActuatorCfg(
    joint_names_expr=[".*_inner_finger_pad_joint", ".*_outer_finger_joint", "right_outer_knuckle_joint"],
    effort_limit_sim=1.0,
    velocity_limit_sim=1.0,
    stiffness=0.0,
    damping=0.0,
    friction=0.0,
    armature=0.0,
)

"""Configuration of UR-3e arm with Robotiq_2F_140_physics_edit gripper."""

C:/Isaaclab/source/isaaclab_tasks/isaaclab_tasks/manager_based/manipulation/stack/config/ur3e_gripper/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

##
# Register Gym environments.
##


##
# Inverse Kinematics - Relative Pose Control
##

gym.register(
    id="Isaac-Stack-Cube-UR3e-IK-Rel-v0",
    entry_point="isaaclab.envs:ManagerBasedRLEnv",
    kwargs={
        "env_cfg_entry_point": f"{__name__}.stack_ik_rel_env_cfg:UR3eGripperCubeStackEnvCfg",
    },
    disable_env_checker=True,
)

C:/Isaaclabsource/isaaclab_tasks/isaaclab_tasks/manager_based/manipulation/stack/config/ur3e_gripper/stack_ik_rel_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.controllers.differential_ik_cfg import DifferentialIKControllerCfg
from isaaclab.devices.device_base import DevicesCfg
from isaaclab.devices.keyboard import Se3KeyboardCfg
from isaaclab.devices.spacemouse import Se3SpaceMouseCfg
from isaaclab.envs.mdp.actions.actions_cfg import DifferentialInverseKinematicsActionCfg
from isaaclab.utils import configclass

from . import stack_joint_pos_env_cfg


@configclass
class UR3eGripperCubeStackEnvCfg(stack_joint_pos_env_cfg.UR3eGripperCubeStackEnvCfg):

    def __post_init__(self):
        super().__post_init__()

        self.actions.arm_action = DifferentialInverseKinematicsActionCfg(
            asset_name="robot",
            joint_names=[".*_joint"],
            body_name="wrist_3_link",
            controller=DifferentialIKControllerCfg(command_type="pose", use_relative_mode=True, ik_method="dls"),
            scale=0.5,
            body_offset=DifferentialInverseKinematicsActionCfg.OffsetCfg(
                pos=(0.0, 0.0, 0.1995), # offset of "2F-140" gripper along z-axis.                                    
                rot=(0.0, -0.7071, 0.0, -0.7071), # set the TCP coords to be looked same direction in provided "Isaac-Stack-Cube-UR10-Long-Suction-IK-Rel-v0" task.
            ),
        )

        self.teleop_devices = DevicesCfg(
            devices={
                "keyboard": Se3KeyboardCfg(
                    pos_sensitivity=0.02,
                    rot_sensitivity=0.05,
                    sim_device=self.sim.device,
                ),
                "spacemouse": Se3SpaceMouseCfg(
                    pos_sensitivity=0.05,
                    rot_sensitivity=0.05,
                    sim_device=self.sim.device,
                ),
            }
        )

C:/Isaaclabsource/isaaclab_tasks/isaaclab_tasks/manager_based/manipulation/stack/config/ur3e_gripper/stack_joint_pos_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.assets import RigidObjectCfg
from isaaclab.managers import EventTermCfg as EventTerm
from isaaclab.managers import SceneEntityCfg
from isaaclab.sensors import FrameTransformerCfg
from isaaclab.sensors.frame_transformer.frame_transformer_cfg import OffsetCfg
from isaaclab.sim.schemas.schemas_cfg import RigidBodyPropertiesCfg, MassPropertiesCfg
from isaaclab.sim.spawners.from_files.from_files_cfg import UsdFileCfg
from isaaclab.utils import configclass
import isaaclab.utils.math as math_utils
import torch
from isaaclab.utils.assets import ISAAC_NUCLEUS_DIR

from isaaclab_tasks.manager_based.manipulation.stack import mdp
from isaaclab_tasks.manager_based.manipulation.stack.mdp import ur3e_stack_events
from isaaclab_tasks.manager_based.manipulation.stack.mdp import franka_stack_events
from isaaclab_tasks.manager_based.manipulation.stack.stack_env_cfg import StackEnvCfg

from isaaclab_assets.robots.universal_robots import (  # isort: skip
    UR3e_ROBOTIQ_GRIPPER_CFG,
)

##
# Pre-defined configs
##
from isaaclab.markers.config import FRAME_MARKER_CFG  # isort: skip


@configclass
class EventCfgUR3eGripper:
    """Configuration for events."""

    init_ur3e_arm_pose = EventTerm(
        func=ur3e_stack_events.set_ur3e_arm_default_joint_pose,
        mode="reset",
        params={
            "default_pose": [0.0, -1.5707, 1.5707, -1.5707, -1.5707, 0.0],
        },
    )
    
    init_ur3e_gripper_pose = EventTerm(
        func=ur3e_stack_events.set_ur3e_gripper_default_joint_pose,
        mode="reset",
        params={
            "default_pose": [0.785],
        },
    )

    # Apply payload of Robotiq 2F-140: mass 2.315 kg, CoM at (0, 0, 0.0714) m in wrist frame
    apply_ur3e_gripper_payload = EventTerm(
        func=ur3e_stack_events.set_ur3e_payload_on_wrist,
        mode="reset",
        params={
            "payload_mass": 2.315,
            "payload_com": [0.0, 0.0, 0.0714],
            "asset_cfg": SceneEntityCfg("robot"),
        },
    )

    randomize_ur3e_joint_state = EventTerm(
        func=ur3e_stack_events.randomize_ur3e_arm_joint_by_gaussian_offset,
        mode="reset",
        params={
            "mean": 0.0,
            "std": 0.02,
            "asset_cfg": SceneEntityCfg("robot"),
        },
    )

    randomize_cube_positions = EventTerm(
        func=franka_stack_events.randomize_object_pose,
        mode="reset",
        params={
            "pose_range": {"x": (0.4, 0.6), "y": (-0.10, 0.10), "z": (0.0203, 0.0203), "yaw": (-1.0, 1.0, 0)},
            "min_separation": 0.1,
            "asset_cfgs": [SceneEntityCfg("cube_1"), SceneEntityCfg("cube_2"), SceneEntityCfg("cube_3")],
        },
    )


@configclass
class UR3eCubeStackEnvCfg(StackEnvCfg):
    cube_properties = RigidBodyPropertiesCfg(
        solver_position_iteration_count=16,
        solver_velocity_iteration_count=1,
        max_angular_velocity=1000.0,
        max_linear_velocity=1000.0,
        max_depenetration_velocity=5.0,
        disable_gravity=False,
    )
    cube_scale = (1.0, 1.0, 1.0)
    marker_cfg = FRAME_MARKER_CFG.copy()
    marker_cfg.markers["frame"].scale = (0.1, 0.1, 0.1)
    marker_cfg.prim_path = "/Visuals/FrameTransformer"

    def __post_init__(self):
        super().__post_init__()

        self.events = EventCfgUR3eGripper()

        self.actions.arm_action = mdp.JointPositionActionCfg(
            asset_name="robot", joint_names=[".*_joint"], scale=0.5, use_default_offset=True
            )
        self.actions.gripper_action = mdp.BinaryJointPositionActionCfg(
            asset_name="robot",
            joint_names=["finger_joint"],  
            open_command_expr={
                "finger_joint": 0.65,           
            },
            close_command_expr={
                "finger_joint": 0.0,                 
            },
        )
        # Only parallel joints are supported?
        self.gripper_joint_names = ["left_inner_finger_joint", "right_inner_finger_joint"]
        self.gripper_open_val = 0.04
        self.gripper_threshold = 0.005

        # cube mass default: 0.02
        # Set mass to 0 for testing
        cube_mass_props = MassPropertiesCfg(mass=0.02)
        self.scene.cube_1 = RigidObjectCfg(
            prim_path="{ENV_REGEX_NS}/Cube_1",
            init_state=RigidObjectCfg.InitialStateCfg(pos=[0.4, 0.0, 0.0203], rot=[1, 0, 0, 0]),
            spawn=UsdFileCfg(
                usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/Blocks/blue_block.usd",
                scale=self.cube_scale,
                rigid_props=self.cube_properties,
                mass_props=cube_mass_props,
            ),
        )
        self.scene.cube_2 = RigidObjectCfg(
            prim_path="{ENV_REGEX_NS}/Cube_2",
            init_state=RigidObjectCfg.InitialStateCfg(pos=[0.55, 0.05, 0.0203], rot=[1, 0, 0, 0]),
            spawn=UsdFileCfg(
                usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/Blocks/red_block.usd",
                scale=self.cube_scale,
                rigid_props=self.cube_properties,
                mass_props=cube_mass_props,
            ),
        )
        self.scene.cube_3 = RigidObjectCfg(
            prim_path="{ENV_REGEX_NS}/Cube_3",
            init_state=RigidObjectCfg.InitialStateCfg(pos=[0.60, -0.1, 0.0203], rot=[1, 0, 0, 0]),
            spawn=UsdFileCfg(
                usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/Blocks/green_block.usd",
                scale=self.cube_scale,
                rigid_props=self.cube_properties,
                mass_props=cube_mass_props,
            ),
        )

        self.decimation = 5
        self.episode_length_s = 30.0
        # simulation settings
        self.sim.dt = 0.01  # 100Hz
        self.sim.render_interval = 5
    
    
@configclass
class UR3eGripperCubeStackEnvCfg(UR3eCubeStackEnvCfg):

    def __post_init__(self):
        # post init of parent
        super().__post_init__()
        
        # Set events
        self.events = EventCfgUR3eGripper()

        # Set UR3e with Gripper as robot
        self.scene.robot = UR3e_ROBOTIQ_GRIPPER_CFG.replace(prim_path="{ENV_REGEX_NS}/Robot")

        self.scene.ee_frame = FrameTransformerCfg(
            prim_path="{ENV_REGEX_NS}/Robot/base_link",
            debug_vis=True,
            visualizer_cfg=self.marker_cfg,
            target_frames=[
                FrameTransformerCfg.FrameCfg(
                    prim_path="{ENV_REGEX_NS}/Robot/wrist_3_link",
                    name="end_effector",
                    offset=OffsetCfg(
                        pos=(0.0, 0.0, 0.1995), # offset of "2F-140" gripper along z-axis.
                        rot=(0.0, -0.7071, 0.0, -0.7071), # set the TCP coords to be looked same direction in provided "Isaac-Stack-Cube-UR10-Long-Suction-IK-Rel-v0" task.
                    ),
                ),
            ],
        )

C:/Isaaclab/source/isaaclab_tasks/isaaclab_tasks/manager_based/manipulation/stack/mdp/ur3e_stack_events.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 __future__ import annotations

import math
import random
import torch
from typing import TYPE_CHECKING

from isaacsim.core.utils.extensions import enable_extension

import isaaclab.utils.math as math_utils
from isaaclab.assets import Articulation, AssetBase
from isaaclab.managers import SceneEntityCfg

if TYPE_CHECKING:
    from isaaclab.envs import ManagerBasedEnv


# Helper constants and functions specific to UR3e arm control
ARM_JOINT_NAMES = [
    "shoulder_pan_joint",
    "shoulder_lift_joint",
    "elbow_joint",
    "wrist_1_joint",
    "wrist_2_joint",
    "wrist_3_joint",
]

GRIPPER_JOINT_NAMES = [
    "finger_joint",
]

def set_ur3e_arm_default_joint_pose(env, env_ids, default_pose, asset_cfg: SceneEntityCfg = SceneEntityCfg("robot")):
    robot = env.scene[asset_cfg.name]
    arm_joint_ids, _ = robot.find_joints(ARM_JOINT_NAMES)
    default_pose_tensor = torch.tensor(default_pose, device=env.device).unsqueeze(0).repeat(len(env_ids), 1)

    # Update only arm joints in the default joint positions
    robot.data.default_joint_pos[env_ids[:, None], arm_joint_ids] = default_pose_tensor
    

def set_ur3e_gripper_default_joint_pose(env, env_ids, default_pose, asset_cfg: SceneEntityCfg = SceneEntityCfg("robot")):
    robot = env.scene[asset_cfg.name]
    gripper_joint_ids, _ = robot.find_joints(GRIPPER_JOINT_NAMES)
    default_pose_tensor = torch.tensor(default_pose, device=env.device).unsqueeze(0).repeat(len(env_ids), 1)

    # Update only gripper joints in the default joint positions
    robot.data.default_joint_pos[env_ids[:, None], gripper_joint_ids] = default_pose_tensor


def randomize_ur3e_arm_joint_by_gaussian_offset(
    env,
    env_ids,
    mean: float,
    std: float,
    asset_cfg: SceneEntityCfg = SceneEntityCfg("robot"),
):
    robot = env.scene[asset_cfg.name]
    arm_joint_ids, _ = robot.find_joints(ARM_JOINT_NAMES)

    joint_pos = robot.data.default_joint_pos[env_ids].clone()
    joint_vel = robot.data.default_joint_vel[env_ids].clone()

    noise = math_utils.sample_gaussian(mean, std, (len(env_ids), len(arm_joint_ids)), joint_pos.device)
    joint_pos[:, arm_joint_ids] += noise

    limits = robot.data.soft_joint_pos_limits[env_ids][:, arm_joint_ids, :]
    joint_pos[:, arm_joint_ids] = torch.clamp(joint_pos[:, arm_joint_ids], limits[..., 0], limits[..., 1])

    robot.set_joint_position_target(joint_pos, env_ids=env_ids)
    robot.set_joint_velocity_target(joint_vel, env_ids=env_ids)
    robot.write_joint_state_to_sim(joint_pos, joint_vel, env_ids=env_ids)


def set_ur3e_payload_on_wrist(
    env: "ManagerBasedEnv",
    env_ids,
    payload_mass: float,
    payload_com: list[float],
    asset_cfg: SceneEntityCfg = SceneEntityCfg("robot"),
):
    """Apply a payload to the UR3e wrist by updating mass and CoM of the wrist link.

    The combined center of mass is computed as a mass-weighted average of the existing wrist link CoM and
    the payload CoM expressed in the wrist link frame.
    """
    robot: Articulation = env.scene[asset_cfg.name]
    # resolve env ids on CPU (writer APIs accept CPU ids)
    if env_ids is None:
        env_ids = torch.arange(env.scene.num_envs, device="cpu")
    else:
        env_ids = env_ids.cpu()
    # find wrist body index
    wrist_ids, _ = robot.find_bodies(["wrist_3_link"])
    if len(wrist_ids) == 0:
        raise RuntimeError("Could not find 'wrist_3_link' in robot bodies.")
    wrist_id = wrist_ids[0]
    # fetch current masses/CoMs (clone to CPU)
    masses = robot.root_physx_view.get_masses().clone().cpu()
    coms = robot.root_physx_view.get_coms().clone().cpu()
    # payload CoM as tensor (meters)
    payload_com_t = torch.tensor(payload_com, dtype=coms.dtype, device="cpu")
    # apply per selected envs
    m0 = masses[env_ids, wrist_id]
    c0 = coms[env_ids, wrist_id, :3]
    m_new = m0 + payload_mass
    c_new = (m0.unsqueeze(-1) * c0 + payload_mass * payload_com_t.unsqueeze(0)) / m_new.unsqueeze(-1)
    masses[env_ids, wrist_id] = m_new
    coms[env_ids, wrist_id, :3] = c_new
    # write back
    robot.root_physx_view.set_masses(masses, env_ids)
    robot.root_physx_view.set_coms(coms, env_ids)

You can find the result video and discussion on the https://discordapp.com/channels/827959428476174346/1439937737708011590

• Please note that I ran cursorAI to write set_ur3e_payload_on_wrist function in the code, so it has been fully inspected yet.

• Isaac Lab Version: 2.2.1

• Isaac Sim Version: 5.0.0

[Ashkanpy]

Hi, I am facing the same problem with UR10e and Robotiq 2F-140! Tried different stiffness and damping, but the problem is not fixed. I am thinking maybe there is a problem with DIK.

[RandomOakForest]

Thank you for posting this. I'll move this post to our Discussions section for now. Here are some notes to consider. This behavior usually comes from the physics / articulation configuration of the UR3e–Robotiq assembly, not from the manager-based workflow itself.

Main likely causes

For a UR+Robotiq stack, the gripper “keeps rotating” around the grasped cube typically because of one or more of these:

• The wrist–gripper attach joint is too loose: low stiffness / damping or too small max force on that fixed or revolute joint. This lets the gripper twist when contact forces appear.¹²
• The finger joints are overpowered or too fast, so when they close on the cube, contact impulses push back on the arm and cause extra rotation or self‑penetration of the gripper links.³¹
• Contact/friction parameters between cube and gripper (or cube and table) are not tuned, so the cube “sticks” or exerts unrealistic torque when lifted.⁴
• In the assembled USD, the Robotiq root or palm frame is not perfectly aligned with the UR3e tool frame, creating a small offset that shows up as rotation when you move after grasping.⁵⁶

What to change in the USD

In Isaac Sim, open your assembled UR3e+Robotiq USD and check:

1. Wrist–gripper joint

• Select the joint that connects UR3e wrist_3_link (or tool0) to the Robotiq palm.
• If it is meant to be rigid, make it a fixed joint or a revolute with:
  • Stiffness: high (start ~1e5–1e6, reduce if unstable).²¹
  • Damping: moderate (e.g., 1e3–1e4).¹²
  • Max force: high enough so it does not yield under grasp loads.
• Ensure “Drive type” is Position and target is zero so it behaves as a stiff connection.¹

2. Finger joints

• For each finger drive (outer_knuckle, inner_knuckle, etc.):
  • Reduce stiffness and max force if the gripper tends to clip into the object or into itself.³¹
  • Limit maximum joint velocity in Joint → Advanced → Maximum Joint Velocity to a realistic value; too high makes contact impulses large.²¹
• If using mimic joints, ensure only one “master” joint has active drive; all mimics should have zeroed drive so they follow kinematically, avoiding over‑constraint.⁷

3. Collision and inertia

• Check there is no collision mesh overlap between UR3e wrist and the Robotiq palm at the attach point; small penetrations can create big torques when contacts resolve.⁶⁷
• Confirm finger collision meshes are not overly thick or intersect each other when closed.

Physics and contact tuning

In your Isaac Sim physics scene or Isaac Lab environment config:

• Increase solver position/velocity iteration counts for better contact stability when grasping.⁴
• Tune friction:
  • Use realistic static/dynamic friction for the cube and gripper materials (e.g. static a bit higher than dynamic so the object does not slip easily).⁴
• If you are commanding the gripper with target positions:
  • Use the ArticulationAction / manager action interface rather than directly teleporting joint positions; letting the PD drive generate motion reduces shocks.⁸⁴

Manager-based environment configs

Within your manager-based stack task (e.g. stack_ik_rel_env_cfg / stack_joint_pos_env_cfg):

• Check action scaling for the arm: large joint position/velocity steps can cause sudden accelerations that twist the gripper around the cube.⁸
• Ensure the cube is spawned with non-zero mass and reasonable inertia so it does not behave like a very light or very heavy object that destabilizes the gripper.²¹
• Consider using the SurfaceGripper component if you want more stable pick behavior with simple blocks; Isaac Lab added support for manager-based workflows via SurfaceGripperAction in recent releases.⁹

Footnotes

1. https://docs.isaacsim.omniverse.nvidia.com/4.5.0/robot_setup/joint_tuning.html ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸

2. https://docs.isaacsim.omniverse.nvidia.com/5.1.0/robot_setup_tutorials/joint_tuning.html ↩ ↩² ↩³ ↩⁴ ↩⁵

3. https://github.com/isaac-sim/IsaacLab/discussions/2120 ↩ ↩²

4. https://forums.developer.nvidia.com/t/object-gripping-and-picking/291963 ↩ ↩² ↩³ ↩⁴

5. https://forums.developer.nvidia.com/t/programmatically-attaching-joint-via-robot-assembler/286224 ↩

6. https://forums.developer.nvidia.com/t/unstable-robot-assembler-in-isaac-sim-4-5/323628 ↩ ↩²

7. https://docs.isaacsim.omniverse.nvidia.com/4.2.0/advanced_tutorials/tutorial_advanced_rigging_complex_structures.html ↩ ↩²

8. https://isaac-sim.github.io/IsaacLab/main/source/api/lab/isaaclab.envs.html ↩ ↩²

9. https://github.com/isaac-sim/IsaacLab/releases ↩

[sandokim]

What to change in the USD

In Isaac Sim, open your assembled UR3e+Robotiq USD and check:

1. Wrist–gripper joint

• Select the joint that connects UR3e wrist_3_link (or tool0) to the Robotiq palm.

• If it is meant to be rigid, make it a fixed joint or a revolute with:

  • Stiffness: high (start ~1e5–1e6, reduce if unstable).21
  • Damping: moderate (e.g., 1e3–1e4).12
  • Max force: high enough so it does not yield under grasp loads.

• Ensure “Drive type” is Position and target is zero so it behaves as a stiff connection.1

Thank you for suggesting, I'm working in Isaacsim for 1. Wrist-gripper joint. I renamed "Robotiq_2F_140_physics_edit.usd" to "ee_link". I assemble the gripper and ur3e with Tools > Robotics > Asset Editors > Robot Assembler.

• Base Robot
  • Select Base Robot: /ur3e
  • Attach Point: wrist_3_link
• Attach Robot
  • Select Attach Robot: /ur3e/ee_link
  • Attach Point: robotiq_base_link
• Assembly Namespace: Gripper

Begin Assemble

• Adjust Attachment Robot Transform
  • X+90 once

Assemble and Simulate
End Simulation And Finish

I noticed there's /ur3e/robotiq_base_link/_F_Body_01/AssemblerFixedJoint after assembling.

I think "AssemblerFixdJoint" is the one you mentioned in "Select the joint that connects UR3e wrist_3_link (or tool0) to the Robotiq palm."

But I couldn't find where to adjust this joint properties "stiffness, damping, and max force" in stage > properties.

Collision and inertia
Collision and inertia
Check there is no collision mesh overlap between UR3e wrist and the Robotiq palm at the attach point; small penetrations can create big torques when contacts resolve.

And how can I check if there's no collision mesh overlap?

I haven't seen any self penetration of fingers in the assembled ur3e+gripper.

[Ashkanpy]

I reduced the rotation by increasing the damping and stiffness of wrist joint 3 and reducing the maximum force of the drive for the finger joint. So I have managed to sort the cubes as blue, red, and green from bottom to top. But the environment does not reset and does not take a successful record. What should I check?

[sandokim]

Could you provide how you set damping and stiffness of wrist joint 3 and maximum force of the drive for the finger joint? Code will be much appreciated.

[Ashkanpy]

In Universal_Robots. Py you can find these configes for the joint wrist 3:

wrist": ImplicitActuatorCfg(
joint_names_expr=["wrist_.*"],
stiffness=216.0,
damping=29.39387691,
friction=0.0,
armature=0.0,

And for the gripper you have:

UR3e_ROBOTIQ_GRIPPER_CFG.actuators["gripper_drive"] = ImplicitActuatorCfg(
joint_names_expr=["finger_joint"],
effort_limit_sim=10.0,
velocity_limit_sim=1.0,
stiffness=11.25,
damping=0.1,
friction=0.0,
armature=0.0,
)

Based on your environment you can set damping and stiffness for the arm and for the gripper you have effort_limit_sim and alfi stiffness and damping

[sandokim]

Yes, I've been tweaking stiffness and damping of each actuator, but I want to know if there is a rule of thumb to adjust the value of stiffness and damping. I cannot confirm which value is the optimal stiffness and damping for ur3e and gripper.

[Ashkanpy]

You need to set the values based on the UR3e workload, IK PD gain, Gripper weight, cubes mass, and weight. UR3e velocity, and almost every factor that influences the performance of the model.