ROS Tf Activity

Demonstration

# create the workspace and clone the repository and get set up
mkdir -p ws/src
cd ws/src
git clone https://github.com/m-elwin/me495_tf.git -b ros2
cd ..
colcon build --symlink-install
source install/setup.bash

# run the broadcaster
ros2 run me495_tf in_out &

# list the topics, notice the /tf and /tf_static
ros2 topic list

# use rqt_tf_tree to see the tf_tree
ros2 run tf2_tools view_frames

# Also can use rqt_tf_tree. Need to install the rqt_tf_tree package
ros2 run rqt_tf_tree rqt_tf_tree

# use tf_echo to see translation between frames. C-c to quit
ros2 run tf2_ros tf2_echo right left

# run in rviz, set everything up correctly
rviz2

# run in rviz, using my rviz config
rviz2 -d src/me495_tf/config/view.rviz

# run the tracker node
ros2 run me495_tf tracker

Exercises

Walk through the demonstration above, manually setting up rviz to display the transformations
Modify in_out so that the base frame is dynamic, that is, it is broadcast from the regular broadcaster and not the static broadcaster.
Make the base frame rotate about it's own z axis at a fixed rate, and visualize in rviz
Add another frame called up that is a child of base. Have this frame move in sync with left and right but perpendicular to them
Modify tracker so that when the distance between up and left is above a threshold, it prints a message

Resources

TF Notes