isaac-sim-ros2-bridge

# Isaac Sim ROS 2 Bridge ## Purpose Publish and subscribe to ROS 2 topics from Isaac Sim using OmniGraph bridge nodes, including Nav2 integration and multi-robot namespacing. ## Limitations - Targets Isaac Sim 6 / Kit 110 unless a section states otherwise. - Does not replace official NVIDIA documentation for unsupported edge cases. ## Troubleshooting | Error / symptom | Cause | Solution | |---|---|---| | No ROS topics | Bridge graph not playing or wrong domain | Press Play; set `ROS_DOMAIN_ID` consistently | | Missing humble libs | `LD_LIBRARY_PATH` not set before process start | Fix the parent shell (source ROS env or use default launcher), then relaunch — do not hot-patch a running process | | Namespaced topic mismatch | Frame or namespace drift | Align OmniGraph namespace with Nav2 config | ## Available Scripts | Script | Purpose | Arguments | |---|---|---| | `scripts/multi_robot_namespacing.py` | Fleet demo: play-gated per-robot bridge graphs (odom, TF, scan, joint states, cmd_vel) + shared clock | `--robots NAME:PRIM_PATH [...]` `--usd_path` `--lidar_suffix` `--headless` `--test` | | `scripts/prerequisites.sh` | Prerequisites | positional args per script header (see script) | ## Running scripts From agent runtimes that expose skill execution helpers, invoke helpers with `run_script()`: ```python run_script("scripts/multi_robot_namespacing.py", args=["--help"]) ``` From a built Isaac Sim tree, run the same file with `./python.sh` (Linux) or `python.bat` (Windows) from `_build/*/release`, or execute shell helpers directly when they do not require the simulator. ## Architecture The ROS 2 Bridge in Isaac Sim 6.0 is extension-based (`isaacsim.ros2.bridge`) and built on OmniGraph action graphs. Publishers, subscribers, and services are **only active when play is pressed**. ### Extension Stack | Extension | Purpose | |-----------|---------| | `isaacsim.ros2.core` | Backend libraries, settings, lightweight ROS 2 libs | | `isaacsim.ros2.nodes` | OmniGraph nodes for topics/services | | `isaacsim.ros2.bridge` | Top-level bridge extension (enables all) | | `isaacsim.ros2.tf_viewer` | TF tree visualization | | `isaacsim.ros2.urdf` | URDF import with ROS 2 conventions | | `isaacsim.ros2.examples` | Sample scenes (Nova Carter, iw_hub, hospital, office) | | `isaacsim.ros2.sim_control` | Simulation control via ROS 2 services | ### Prerequisites No manual setup is required for the default workflow. When `isaacsim.ros2.core` starts, it reads `ROS_DISTRO`; if unset, it falls back to the lightweight ROS 2 libs bundled inside the extension and sets `internal_lib_fallback=True`. The `isaac-sim.sh` / `python.sh` launchers auto-source `setup_ros_env.sh`, which exports `ROS_DISTRO`, `RMW_IMPLEMENTATION`, and the bundled ROS library path before the process starts. Source a system ROS 2 install (`/opt/ros/<distro>/setup.bash`) in the parent shell only when you need message types or RMW implementations not provided by the bundled libs. On Linux, any `LD_LIBRARY_PATH` changes must exist before launching Isaac Sim because the dynamic linker reads them at process start; changing `LD_LIBRARY_PATH` after the process is already running does not retroactively fix ROS library resolution. Pass `--no-ros-env` to bypass the auto-sourcing; in that case the parent shell must provide a working ROS 2 environment, including any required `LD_LIBRARY_PATH` entries. ### ROS Environment Decision Rule Use this precedence order when a user reports ROS 2 bridge startup or symbol-resolution issues: 1. **Default path:** launch via `isaac-sim.sh` / `python.sh` and let `setup_ros_env.sh` provide the bundled ROS environment. 2. **System ROS path:** if custom message packages or alternate RMW implementations are required, source `/opt/ros/<distro>/setup.bash` (and any overlay workspace) in the parent shell *before* launch. 3. **Do not hot-patch `LD_LIBRARY_PATH`:** if Isaac Sim is already running with the wrong loader environment, restart from a correctly sourced shell instead of trying to repair the process in-place. Treat "export `LD_LIBRARY_PATH` and retry inside the current Isaac Sim process" as an anti-pattern; the corrective action is always "fix the parent shell, then relaunch." <!-- CODE: scripts/prerequisites.sh --> *[Code: `scripts/prerequisites.sh`]* ## OmniGraph ROS 2 Nodes All ROS 2 communication is configured through OmniGraph action graphs. Key node types: ### Publishers | Node Type | Topic Type | Use Case | |-----------|-----------|----------| | `ROS2PublishClock` | `rosgraph_msgs/Clock` | Sim time sync | | `ROS2PublishJointState` | `sensor_msgs/JointState` | Joint positions/velocities | | `ROS2PublishOdometry` | `nav_msgs/Odometry` | Robot odometry | | `ROS2PublishLaserScan` | `sensor_msgs/LaserScan` | Lidar data | | `ROS2PublishImage` | `sensor_msgs/Image` | Camera RGB/depth | | `ROS2PublishCameraInfo` | `sensor_msgs/CameraInfo` | Camera intrinsics | | `ROS2PublishTransformTree` | `tf2_msgs/TFMessage` | TF frames | | `ROS2PublishSemanticLabels` | `std_msgs/String` | Semantic segmentation labels | | `ROS2PublishPointCloud` | `sensor_msgs/PointCloud2` | Lidar/depth point clouds | | `ROS2PublishImu` | `sensor_msgs/Imu` | IMU data | ### Subscribers | Node Type | Topic Type | Use Case | |-----------|-----------|----------| | `ROS2SubscribeJointState` | `sensor_msgs/JointState` | Joint commands | | `ROS2SubscribeTwist` | `geometry_msgs/Twist` | Velocity commands (cmd_vel) | | `ROS2SubscribeAckermannDrive` | `ackermann_msgs/AckermannDriveStamped` | Ackermann steering commands | ### Generic / extra | Node Type | Use case | |---|---| | `ROS2Publisher` / `ROS2Subscriber` | generic publish/subscribe for arbitrary message types | | `ROS2PublishBoundingBox2D` / `ROS2PublishBoundingBox3D` | annotator output to ROS 2 | | `ROS2PublishRgbd` | combined RGB+D publishing | | `ROS2PublishSemanticSegmentation` / `ROS2PublishInstanceSegmentation` | segmentation outputs | ## Setting Up a ROS 2 Bridge Graph (Python) The repo ships a canonical reference for building a ROS 2 publishing action graph with `og.Controller.edit(...)`, including connecting `OnPlaybackTick` to publisher nodes, wiring `IsaacReadSimulationTime` into a `ROS2PublishClock`, and creating a matching `rclpy` subscriber inside the same script. - Reference example: `source/standalone_examples/api/isaacsim.ros2.bridge/clock.py` When extending this pattern, use the current `isaacsim.ros2.bridge.ROS2Publish*` / `ROS2Subscribe*` node names (the legacy `omni.isaac.ros2_bridge.*` namespace is deprecated and will not load on Kit 110). > **Migration:** see [Migrating ROS 2 OmniGraph nodes](https://docs.isaacsim.omniverse.nvidia.com/latest/migration_guides/isaac_sim_6_0/ros2_omnigraph_migration.html) for the node-by-node rename map, and [Renaming Extensions](https://docs.isaacsim.omniverse.nvidia.com/latest/migration_guides/isaac_sim_4_5/extensions_renaming.html) for the broader `omni.isaac.*` → `isaacsim.*` mapping. ## Multi-Robot Namespacing For multi-robot scenes, each robot needs its own namespace for ROS 2 topics. The repo's multi-robot scenario (Carter on hospital/office) demonstrates the manual loading + per-robot setup pattern; `scripts/multi_robot_namespacing.py` in this skill provides the full fleet bridge factory. - Scenario reference: `source/standalone_examples/api/isaacsim.ros2.bridge/carter_multiple_robot_navigation.py` - Fleet graph factory: `scripts/multi_robot_namespacing.py` ### Play-Gated Activation All bridge graphs use `OnPlaybackTick` as their execution trigger. This means: 1. Graphs are created while the stage is in a stopped state (no topics published). 2. Once `app_utils.play()` is called (or Play is pressed in the GUI), `OnPlaybackTick` fires each frame and drives all connected publishers/subscribers. 3. Stopping playback immediately silences all topics. This is the correct pattern for fleet demos — Nav2 nodes can be launched and waiting before topics appear, and the fleet begins publishing atomically when Play starts. ### API Usage ```python from multi_robot_namespacing import setup_fleet, create_ros2_bridge_for_robot # Full fleet setup (clock + per-robot graphs) setup_fleet([ ("carter1", "/World/Carter1"), ("carter2", "/World/Carter2"), ("carter3", "/World/Carter3"), ]) # Or create individual robot graphs create_ros2_bridge_for_robot( robot_name="carter1", robot_prim_path="/World/Carter1", lidar_prim_path="/World/Carter1/Lidar", publish_joint_states=True, ) ``` ### Per-Robot Published Topics (after Play) | Topic | Message Type | Frame | |-------|-------------|-------| | `/<name>/odom` | `nav_msgs/Odometry` | `<name>/odom` → `<name>/base_link` | | `/<name>/scan` | `sensor_msgs/LaserScan` | `<name>/lidar_link` | | `/<name>/joint_states` | `sensor_msgs/JointState` | — | | `/tf` | `tf2_msgs/TFMessage` | robot subtree | | `/clock` | `rosgraph_msgs/Clock` | shared, one graph | ### Subscribed Topics | Topic | Message Type | Use | |-------|-------------|-----| | `/<name>/cmd_vel` | `geometry_msgs/Twist` | Velocity commands from Nav2 | ## Nav2 Integration To use Nav2 with Isaac Sim ROS 2 Bridge: 1. Publish required topics: `/odom`, `/tf`, `/scan` (or `/pointcloud`), `/joint_states` 2. Subscribe to: `/cmd_vel` 3. Publish sim clock on `/clock` and set `use_sim_time: true` in Nav2 params ## Known Issues (Isaac Sim 6.0 rc.22) - ROS 2 bridge only activates on `timeline.play()` — topics are not published in stopped state - Camera publishers require camera prims to have render products attached - TF tree can become inconsistent if robot prim paths change at runtime - Bundled ROS 2 libs may lack message types needed for custom topics — source a system ROS 2 install in the parent shell before launching Isaac Sim ## Sample Scenes Pre-built example USD files (from `isaacsim.ros2.examples`): | Scene | Path | Description | |-------|------|-------------| | Nova Carter Navigation | `/Isaac/Samples/ROS2/Scenario/carter_warehouse_navigation.usd` | Single robot Nav2 | | Nova Carter Joint States | `/Isaac/Samples/ROS2/Scenario/carter_warehouse_navigation_joint_states.usd` | With joint state publishing | | iw_hub Navigation | `/Isaac/Samples/ROS2/Scenario/iw_hub_warehouse_navigation.usd` | iw_hub AMR | | Multi-Robot Navigation | ROS2/Navigation/Multiple Robots category | Fleet Nav2 | | Hospital Scene | `/Isaac/Samples/ROS2/Scenario/hospital_scene.usd` | Perceptor + hospital | | Office Scene | `/Isaac/Samples/ROS2/Scenario/office_scene.usd` | Office navigation |