[Question] Using OperationalSpaceController in the Isaac-Stack-Cube-Franka-IK-Rel-Visuomotor-v0 task.

[HanwenWangBUPT]

Dear Developers,
I am currently conducting imitation learning research in the simulator. In the Isaac-Stack-Cube-Franka-IK-Rel-Visuomotor-v0 task provided in IsaacLab, the controller for Panda is set to IK. I would like to use the OperationalSpaceController instead. How should I modify the configuration file to achieve this? I have seen the tutorial at [(https://isaac-sim.github.io/IsaacLab/main/source/tutorials/05_controllers/run_osc.html)], but I am still unsure how to proceed and would appreciate your guidance.

[RandomOakForest]

Thank you for posting this. I'll move the question to our Discussions section for follow up. Here is a summary that is still under review but it may be of help.

To replace the inverse kinematics (IK) controller with the Operational Space Controller (OSC) for the Franka arm in the Isaac-Stack-Cube-Franka-IK-Rel-Visuomotor-v0 task in IsaacLab, you need to modify the task’s configuration—specifically, the controller specified under the actions.arm_action.controller section. The default typically looks like a DifferentialIKController configuration. Here’s how you can adapt it to use OSC¹²:

1. Update the Controller in the Configuration File

Locate the configuration for your environment—commonly found in a file named like stack_ik_rel_visuomotor_env_cfg.py, or stack_ik_rel_blueprint_env_cfg.py. Find the actions.arm_action entry, which usually looks like this (simplified):

self.actions.arm_action = DifferentialInverseKinematicsActionCfg(
    asset_name="robot",
    joint_names=["panda_joint.*"],
    body_name="panda_hand",
    controller=DifferentialIKControllerCfg(command_type="pose", use_relative_mode=True, ik_method="dls"),  # <-- to change
    scale=0.5,
    # ...
)

Replace the DifferentialIKControllerCfg(...) with an instance of OperationalSpaceControllerCfg. For example:

from isaaclab.controllers.operational_space_cfg import OperationalSpaceControllerCfg

self.actions.arm_action = TorqueActionCfg(  # You may need to switch to TorqueActionCfg if using OSC
    asset_name="robot",
    joint_names=["panda_joint.*"],
    body_name="panda_hand",
    controller=OperationalSpaceControllerCfg(
        target_types=["pose_abs"],
        impedance_mode="variable_kp",
        inertial_dynamics_decoupling=True,
        partial_inertial_dynamics_decoupling=False,
        gravity_compensation=True,
        motion_control_axes_task=[1, 1, 1, 1, 1, 1],
        contact_wrench_control_axes_task=[0, 0, 0, 0, 0, 0],
        nullspace_control="position"
    ),
    scale=1.0,
    # You may want to specify body_offset or other params
)

• The key is to set controller to OperationalSpaceControllerCfg with appropriate settings for your task.
• If your action term uses something IK-specific like DifferentialInverseKinematicsActionCfg, switch to a torque-based action term such as TorqueActionCfg, because OSC returns joint efforts/torques¹².
• Tune the target_types and impedance settings as required for your task; for plain pose control use ["pose_abs"]. If you want hybrid force-motion control, consider ["pose_abs", "wrench_abs"] and set motion_control_axes_task/contact_wrench_control_axes_task accordingly.

2. Additional Notes

• Observation and reward terms generally do not need modification, but if your system was assuming IK-based actions (i.e., joint position), you should ensure downstream consumers expect torques/efforts.
• Gravity compensation should match your physical simulation; set it to True unless explicitly disabled (see tutorial).
• You may also need to check and update any code handling environment resets, action scaling, or visualization, but the above configuration is the primary change required.
• You will find similar configurations for OSC in the IsaacLab tutorial at tutorials/05_controllers/run_osc.py, which demonstrates instantiating and using OSC¹².
• For full class details and parameters, refer to the latest API documentation for OperationalSpaceController².

Summary:
To use OSC, update your configuration to use OperationalSpaceControllerCfg (with matching TorqueActionCfg if the config requires it). Ensure parameters like target_types and impedance settings are in line with your requirements. This is the central step to switching Franka’s controller in your stacking task from IK to OSC in IsaacLab¹².

Footnotes

1. https://isaac-sim.github.io/IsaacLab/main/source/tutorials/05_controllers/run_osc.html ↩ ↩² ↩³ ↩⁴

2. https://isaac-sim.github.io/IsaacLab/main/source/api/lab/isaaclab.controllers.html ↩ ↩² ↩³ ↩⁴ ↩⁵