ROS2 CAN Package

Prerequisite

This Guide requires that you have an ODrive running and are able to communicate over CAN. If you have not already, please follow the Getting Started Guide and the CAN Bus Guide before continuing.

Note

The following documentation assumes a basic understanding of ROS2 concepts, workspaces, and tools. For a refresher on these topics, you can find the ROS2 documentation here.

Compatibility

See here.

Setting Up the ODrive

Using the Web GUI (Configuration > Interfaces), assign a unique node ID to each ODrive on the bus and enable feedback messages according to the screenshot below:

../_images/gui-can-config.png

Verify these messages are working properly with:

  • candump can0 -xct z -n 10, or

  • python3 -m can.viewer -c "can0" -i "socketcan".

Installing the odrive_can Package

  1. Clone the official odrive_can repository into the src folder of your ROS2 workspace.

  2. Navigate to the top level of the ROS2 workspace folder and run;

    colcon build --packages-select odrive_can
    
  3. Source the workspace:

    source ./install/setup.bash
    
  4. Run the example launch file:

    ros2 launch odrive_can example_launch.yaml
    

Hint

This example assumes the axis node_id is 0, and the CAN network interface is “can0”. These expected values can be changed in ./launch/example_launch.yaml

Inspection

Note

The following commands assume the odrive_can_node is within the namespace odrive_axis0 (set in ./launch/example_launch.yaml).

Once the node is running you can verify everything is setup correctly by running some basic ROS commands in another terminal:

  1. Source the workspace (this needs to be done each time you open a new terminal session):

    source ./install/setup.bash
    
  2. Show feedback from the ODrive:

    ros2 topic echo /odrive_axis0/controller_status
    
    ros2 topic echo /odrive_axis0/odrive_status
    
  3. Request a new state. For example to request CLOSED_LOOP_CONTROL (8):

    ros2 service call /odrive_axis0/request_axis_state odrive_can/srv/AxisState "{axis_requested_state: 8}"`
    

    Full list of axis_requested_state codes: AxisState

  4. Send setpoints. For example this command requests a velocity of 1.0 turns/s in velocity ramp mode:

    ros2 topic pub /odrive_axis0/control_message odrive_can/msg/ControlMessage "{control_mode: 2, input_mode: 1, input_pos: 0.0, input_vel: 1.0, input_torque: 0.0}"