/omni.add_on.ros_control_bridge

ROS Control Bridge for NVIDIA Omniverse Isaac Sim (Low Level Controllers for MoveIt)

MIT LicenseMIT

ROS Control Bridge (add-on) for NVIDIA Omniverse Isaac Sim



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This repository has been integrated into semu.robotics.ros_bridge, in which its source code has been released.

Visit semu.robotics.ros_bridge

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This extension enables the ROS action interfaces used for controlling robots. Particularly those used by MoveIt to talk with the controllers on the robot (FollowJointTrajectory and GripperCommand)


Table of Contents


Prerequisites

All prerequisites described in ROS & ROS2 Bridge must be fulfilled before running this extension. In addition, this extension requires the following extensions to be present in Isaac Sim:


Add the extension to an NVIDIA Omniverse app and enable it

  1. Add the the extension by following the steps described in Extension Search Paths or simply download and unzip the latest release in one of the extension folders such as PATH_TO_OMNIVERSE_APP/exts

    Git url (git+https) as extension search path:

    git+https://github.com/Toni-SM/omni.add_on.ros_control_bridge.git?branch=main&dir=exts

  2. Enable the extension by following the steps described in Extension Enabling/Disabling


Control your robot using MoveIt

Concepts

MoveIt's move_group talks to the robot through ROS topics and actions. Three interfaces are required to control the robot. Go to the MoveIt website to read more about the concepts behind it

  • Joint State information: the /joint_states topic (publisher) is used to determining the current state information

  • Transform information: the ROS TF library is used to monitor the transform information

  • Controller Interface: move_group talks to the controllers on the robot using the FollowJointTrajectory action interface. However, it is possible to use other controller interfaces to control the robot

Configuration

Isaac Sim side

  1. Import your robot from an URDF file using the URDF Importer extension. Go to ROS Wiki: Using Xacro to convert your robot description form .xacro to .urdf

  2. Add a Joint State topic using the menu (Create > Isaac > ROS > Joint State) according to the ROS Bridge extension

  3. Add a TF topic using the menu (Create > Isaac > ROS > Pose Tree) according to the ROS Bridge extension

  4. Add the corresponding ROS control actions implemented by this extension (see the sections below) according to your robotic application's requirements

    Note: At that point, it is recommendable to setup the MoveIt YAML configuration file first to know the controllers' names and the action namespaces

  5. Play the editor to activate the respective topics and actions. Remember the editor must be playing before launching the move_group

MoveIt side

  1. Launch the MoveIt Setup Assistant and generate a new configuration package loading the same .xacro or .urdf used in Isaac Sim. Also, select the same ROS controller interfaces inside the step ROS Control

    roslaunch moveit_setup_assistant setup_assistant.launch

  2. Launch the move_group using the configured controllers

    For example, you can use the next launch file (sample.launch) which is configured to support the FollowJointTrajectory and GripperCommand controllers (panda_gripper_controllers.yaml) by replacing the panda_moveit_config with the generated folder's name and /panda/joint_state with the Isaac Sim joint state topic name

    roslaunch moveit_config sample.launch

    panda_gripper_controllers.yaml

    controller_list:
- name: panda_arm_controller
    action_ns: follow_joint_trajectory
    type: FollowJointTrajectory
    default: true
    joints:
    - panda_joint1
    - panda_joint2
    - panda_joint3
    - panda_joint4
    - panda_joint5
    - panda_joint6
    - panda_joint7
- name: panda_gripper
    action_ns: gripper_command
    type: GripperCommand
    default: true
    joints:
    - panda_finger_joint1
    - panda_finger_joint2

    sample.launch

    <launch>
    <!-- Load the URDF, SRDF and other .yaml configuration files on the param server -->
    <include file="$(find panda_moveit_config)/launch/planning_context.launch">
        <arg name="load_robot_description" value="true"/>
    </include>

    <!-- Publish joint states -->
    <node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher">
        <rosparam param="/source_list">["/panda/joint_state"]</rosparam>
    </node>
    <node name="joint_state_desired_publisher" pkg="topic_tools" type="relay" args="joint_states joint_states_desired"/>

    <!-- Given the published joint states, publish tf for the robot links -->
    <node name="robot_state_publisher" pkg="robot_state_publisher" type="robot_state_publisher" respawn="true" output="screen" />

    <!-- Run the main MoveIt executable -->
    <include file="$(find panda_moveit_config)/launch/move_group.launch">
        <arg name="allow_trajectory_execution" value="true"/>
        <arg name="info" value="true"/>
        <arg name="debug" value="false"/>
    </include>

    <!-- Run Rviz (optional) -->
    <include file="$(find panda_moveit_config)/launch/moveit_rviz.launch">
        <arg name="debug" value="false"/>
    </include>
</launch>

    Also, you can modify the demo.launch file and disable the fake controller execution inside the main MoveIt executable

    <arg name="fake_execution" value="false"/>

  3. Use the Move Group C++ or Python interfaces to control the robot


Configure a FollowJointTrajectory action

To add a FollowJointTrajectory action go to menu Create > Isaac > ROS Control and select Follow Joint Trajectory

To connect the schema with the robot of your choice, select the root of the articulation tree by pressing the Add Target(s) button under the articulationPrim field. Press the play button in the editor, and the topics related to this action will be activated for use

The communication shall take place in the namespace defined by the following fields:

rosNodePrefix + controllerName + actionNamespace

The following figure shows a FollowJointTrajectory schema configured to match the panda_gripper_controllers.yaml described above

followjointtrajectory


Configure a GripperCommand action

To add a GripperCommand action go to menu Create > Isaac > ROS Control and select Gripper Command

To connect the schematic to the end-effector of your choice, first select the root of the articulation tree and then select each of the end-effector's articulations to control following this strict order. This can be done by pressing the Add Target(s) button repeatedly under the articulationPrim field. Press the play button in the editor, and the topics related to this action will be activated for use

The communication shall take place in the namespace defined by the following fields:

rosNodePrefix + controllerName + actionNamespace

The GripperCommand action definition doesn't specify which joints will be controlled. The value manage by this action will affect all the specified joints equally


The following figure shows a GripperCommand schema configured to match the panda_gripper_controllers.yaml described above

grippercommand