Working with ROS2 Foxy
Working at the ROS level for low-level control.
Even if gRPC clients are available to control Reachy without knowing how to use ROS, you may want to work at the ROS level to implement new things for Reachy or use the tools provided by ROS. In this page, we will describe how to use the specfic ROS2 packages for Reachy.
Reachy runs natively on ROS2 Foxy. ROS stands for Robotic Operating System, it offers a huge variety of compatible algorithms and hardware drivers.
The embedded NUC computer comes with ROS2 and Reachy specific packages already installed and running. They provide full access to Reachy. You can:
- get the /joint_state and publish joint goals
- use Rviz
- subscribe to various sensor topic (camera, force sensor, etc)
- access client for IK/FK
NOTE: If you don’t know how to use ROS but still want to do it on Reachy, you should check the official ROS documentation, espcecially the tutorials showing examples and presenting the different key notions introduced by ROS.
What is runnning by default
If you have a Full kit or a Starter kit, reachy_sdk_server.service is enabled by default, meaninig that all Reachy ROS2 packages presented in the Overall presentation are automatically launched when you start the robot.
If you have a Reachy mobile, reachy_mobile_base.service is enabled along with reachy_sdk_server.service.
See section Using services for more information on the services).
You can check all ROS2 topics/services running on Reachy with:
ros2 topic list
and
ros2 service list
Launching nodes individually
The following presents what launch files can be launched, if you don’t whant to use the service. If you want to learn more about what is run by each launch file, check the README of the corresponding package.
Controllers nodes
To control joints, fans and cameras.
Cameras nodes
Cameras nodes are available for full/starter kit only:
To launch the camera view node ROS services:
ros2 launch reachy_controllers camera_publisher.launch.py
To launch the camera zoom node ROS services:
ros2 launch reachy_controllers camera_zoom_service.launch.py
To launch all reachy_controllers nodes related to the cameras ROS services:
ros2 launch reachy_controllers camera_controller.launch.py
To launch the camera focus node ROS services:
ros2 launch reachy_focus camera_focus.launch.py
Joints nodes
To launch the node related to the motors and fans ROS services:
ros2 launch reachy_controllers joint_state_controller.launch.py
All controllers nodes
To launch all controllers nodes related to ROS services at once:
ros2 launch reachy_controllers reachy_controllers.launch.py
Use reachy_msgs to interact with the services. Examples are available here.
Kinematics nodes
Kinematics services are available to provide inverse and forward kinematics services for the arms, as well as inverse kinematics for Orbita, the spherical joint used in Reachy’s neck.
Launch files are available to start the ROS services you need:
To launch description service with URDF (required by the kinematics services):
ros2 launch reachy_kinematics description.launch.py
To launch arms ROS services:
ros2 launch reachy_kinematics arm_kinematics.launch.py
To launch orbita ROS services (full/starter kit only):
ros2 launch reachy_kinematics orbita_kinematics_service.launch.py
To launch all kinematics ROS services at once:
ros2 launch reachy_kinematics kinematics.launch.py
Mobile base
To launch the mobile base Hardware Abstraction Layer node:
ros2 launch zuuu_hal hal.launch.py
Many parameters on the mobile base like the maximum velocity can only be tuned at the ROS level. Check the mobile base’s HAL README to learn about what you can do with the mobile base at the ROS level.
SDK server nodes
A layer above ROS, you can interact with Reachy SDK API. The Python SDK offers a gRPC (Remote Procedure Call) interface to communicate with the server.
To communicate with Reachy through the SDK, you need to launch server nodes that handle gRPC services.
To launch the node for the joints, fans and kinematics gRPC services:
ros2 launch reachy_sdk_server reachy_sdk_server.launch.py
To launch the node for the cameras view and zoom gRPC services (full/starter kit only):
ros2 launch reachy_sdk_server camera_server.launch.py
To launch all nodes for gRPC services:
ros2 launch reachy_sdk_server reachy_camera_sdk_server.launch.py
Note: For the servers to work, the required ROS services must be already launched.
reachy_sdk_serverrequires all kinematics and controllers ROS nodes (for joints and cameras).
To launch the node for the mobile base gRPC services (mobile kit only):
ros2 launch mobile_base_sdk_server mobile_base_sdk_server.launch.py