BotWheel Explorer ROS2 Package

Work In Progress

This package contains:

• Hardware descriptor (URDF) files for the BotWheel Explorer.
• A launch file that allows to drive the robot around by sending geometry_msgs/msg/TwistStamped messages.

See also: odrive_ros2_control

Architecture

The system launched by botwheel_explorer.launch.py looks like this:

Usage Instructions

This assumes that your ODrives are already configured (with node_id 0 and 1) according to the docs and ready to go.

1. Clone this repository
   • Either into your existing colcon workspace if you have one. In this case run all following commands in your workspace.
   • Or as a standalone directory. In this case switch to the cloned directory and run all following commands from there.
2. Install Dependencies

   rosdep install --from-paths odrive_ros2_control odrive_botwheel_explorer -y --ignore-src
   

1. Build

   colcon build --symlink-install --packages-up-to odrive_botwheel_explorer
   

1. Launch

   source ./install/setup.sh
   ros2 launch odrive_botwheel_explorer botwheel_explorer.launch.py
   

When the system finishes launching (may take a few seconds on a slow machine), the ODrives with node_id 0 and 1 should automatically go active.

When you exit this command, the ODrives disarm if their watchdog was enabled.

1. Inspect that the topics are available

   $ ros2 control list_hardware_interfaces
   command interfaces
           left_wheel_joint/effort [available] [unclaimed]
           left_wheel_joint/position [available] [unclaimed]
           left_wheel_joint/velocity [available] [claimed]
           right_wheel_joint/effort [available] [unclaimed]
           right_wheel_joint/position [available] [unclaimed]
           right_wheel_joint/velocity [available] [claimed]
   state interfaces
           left_wheel_joint/effort
           left_wheel_joint/position
           left_wheel_joint/velocity
           right_wheel_joint/effort
           right_wheel_joint/position
           right_wheel_joint/velocity
   

As you can see, there are two joints (two wheels) that have their velocity command interface claimed (by the DiffDriveController) and provide position and velocity feedback.

   $ ros2 topic list
   /botwheel_explorer/cmd_vel
   /botwheel_explorer/odom
   /botwheel_explorer/transition_event
   /diagnostics
   /dynamic_joint_states
   /joint_state_broadcaster/transition_event
   /joint_states
   /parameter_events
   /robot_description
   /rosout
   /tf
   /tf_static
   

1. Check ODrive feedback

```bash $ ros2 topic echo /joint_states — header: stamp: sec: 1706131922 nanosec: 319699404 frame_id: ‘’ name:

• left_wheel_joint

File truncated at 100 lines see the full file