> For the complete documentation index, see [llms.txt](https://docs.hello-robot.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.hello-robot.com/stretch4-ros2-repo/readme.md). # README ### Overview This repository holds ROS 2 Jazzy packages for the Stretch 4 mobile manipulator from Hello Robot Inc. On a fresh robot, these packages are built and available through the `~/ament_ws` workspace. Stretch 4 ROS packages contain breaking changes from Stretch 3 and earlier hardware versions. ROS packages for earlier versions can be found in [stretch\_ros2](https://github.com/hello-robot/stretch_ros2). ### Packages | Resource | Description | | ------------------------------------------------------------------------ | --------------------------------------------------------------------------------------------------- | | [stretch\_core](/stretch4-ros2-repo/stretch_core.md) | ROS 2 drivers for Stretch 4 | | [stretch\_description](/stretch4-ros2-repo/stretch_description.md) | Visualize Stretch 4's URDF | | [stretch\_nav2](/stretch4-ros2-repo/stretch_nav2.md) | Navigation stack built on Nav2 | | [stretch\_simulation](/stretch4-ros2-repo/stretch_simulation.md) | Simulation of Stretch 4, built on [Stretch4 Mujoco](https://github.com/hello-robot/stretch4_mujoco) | | [stretch\_tag\_perception](/stretch4-ros2-repo/stretch_python_bridge.md) | Detect aruco tags with Stretch 4 | | [stretch\_python\_bridge](/stretch4-ros2-repo/stretch_python_bridge.md) | A high-level Python API that abstracts away rclpy | | [hello\_helpers](/stretch4-ros2-repo/hello_helpers.md) | Miscellaneous helper code used across the stretch\_ros2 repository | ### Licenses For license details for this repository, see the LICENSE files found in the directories. A summary of the licenses follows: | Directory | License | | ------------------------ | ------------------------------------------------------------------------------------- | | stretch\_core | [Apache 2.0](http://www.apache.org/licenses/LICENSE-2.0) | | stretch\_description | [BSD 3-Clause Clear License](https://choosealicense.com/licenses/bsd-3-clause-clear/) | | stretch\_nav2 | [Apache 2.0](http://www.apache.org/licenses/LICENSE-2.0) | | stretch\_simulation | [Apache 2.0](http://www.apache.org/licenses/LICENSE-2.0) | | stretch\_tag\_perception | [Apache 2.0](http://www.apache.org/licenses/LICENSE-2.0) | | stretch\_python\_bridge | [Apache 2.0](http://www.apache.org/licenses/LICENSE-2.0) | | hello\_helpers | [Apache 2.0](http://www.apache.org/licenses/LICENSE-2.0) | ### Common ROS2 commands Below is an unordered list of common or useful ROS2 commands: * Start Stretch Driver: `ros2 launch stretch_core stretch_driver.launch.py` * Teleop twist keyboard: `ros2 run teleop_twist_keyboard teleop_twist_keyboard` * Start Lidars: `ros2 launch stretch_core dual_hesai.launch.py` * Start Cameras: `ros2 launch stretch_core luxonis.launch.py use_center:=true use_left:=true use_right:=true` for the head cameras and `ros2 launch stretch_core gripper_camera.launch.py` for the gripper camera. * Navigation (See ): * Start Mapping: `ros2 launch stretch_nav2 offline_mapping.launch.py` and `stretch_gamepad_teleop` * Save a map: `ros2 run nav2_map_server map_saver_cli -f ${HELLO_FLEET_PATH}/maps/` * Start nav2: `ros2 launch stretch_nav2 navigation_mppi.launch.py map:=${HELLO_FLEET_PATH}/maps/.yaml` * Web teleop (See ): `~/ament_ws/src/stretch4_web_teleop/launch_interface.sh` and navigate to `https://localhost/operator` * Record rosbags/mcap files: `ros2 bag record -a` . Note: `-a` records all the topics, if lidar and cameras are streaming, a few minutes of recording are hundreds of gigabytes large. * Play rosbags/mcap files: `ros2 bag play ./path/to/recording` * View topics: `ros2 topic list` and `ros2 topic echo /joint_states` * View kinematic links: `ros2 run tf2_tools view_frames` * View transform between two links: `ros2 run tf2_ros tf2_echo base_link head_link` ### Troubleshooting #### Zenoh middleware not working Zenoh should start as a linux user service on Stretch 4. Run `systemctl --user status zenoh.service` to see if it has failed to start. Run `systemctl --user restart zenoh.service` to restart it. If you would like to manually start it, use `ros2 run rmw_zenoh_cpp rmw_zenohd`. #### rviz2 is not launching with a Launch file There is a known conflict between opencv and rviz2 in ROS2 Jazzy that is documented and a solution is proposed here: #### Topics are not appearing There are a number of reasons for topics to not appear. 1. Check that you are running the ros2 node and the client on the same computer. If you are trying to connect from a different computer, you may need to add the following environment variables to your client session: ``` export RMW_IMPLEMENTATION=rmw_zenoh_cpp # Replace ROBOT_IP with your Stretch's IP address ROBOT_IP=192.168.X.XXX export ZENOH_CONFIG_OVERRIDE='mode="client";connect/endpoints=["tcp/$ROBOT_IP:7447"]' ``` 2. Stretch 4 is configured with `export RMW_IMPLEMENTATION=rmw_zenoh_cpp` in the .bashrc file to tell ROS2 to use the Zenoh middleware. Make sure your terminal session with this env variable. 3. Use `ros2 topic list` to list topics. Also, `ros2 topic echo /joint_states` to listen to a topic 4. Check that the TF tree has all the links: `ros2 run tf2_tools view_frames`
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