WBC ROS 2 - Nullspace Example
To run a nullspace example, you can do
ros2 launch wbc_ros null_space_example.launch.py
Again, to visualize the robot, you can do
rviz2 -d install/wbc_ros/share/wbc_ros/config/default.rviz
You should now see the KUKA iiwa robot in rviz. The robot maintains a fixed end effector pose, while moving the elbow joint along a trajectory.
In the nullspace_example.launch.py file, the code to load the example is explained step by step. This iiwa_controllers.yaml file describes the ROS 2 control configuration, which is loaded in the launch file.
If you type ros2 control list_controllers you can see the available controllers:
joint_state_broadcaster[joint_state_broadcaster/JointStateBroadcaster] active
whole_body_controller[wbc_ros/WholeBodyController] active
ee_pose_controller [wbc_ros/CartesianPositionController] active
elbow_pose_controller[wbc_ros/CartesianPositionController] active
Here, the end effector task has a higher priority (0) than the elbow task (1).