Skip to content

Waypoint Following

Jump to bottom
Brian Goldfain edited this page Jun 29, 2016 · 23 revisions

The waypointFollower controller steers the AutoRally platform between successive waypoints that are defined in the global coordinate frame used by the state estimator.

Waypoint Follower

We provide an example waypoints file recorded in the simulation track. The waypointFollower loads the provided waypoints file by default, but can be changed in the launch file.

Launch the waypointFollower to steer the AutoRally platform with the following procedure:

  • Run some method to control the platform (gamepad in simulation or transmitter in the real world)

  • Run the stateEstimator and ensure it has converged

  • Drive the AutoRally platform to the start of the waypoints. For the provided waypoints file taken in simulation this location is the spawn location of the platform.

  • If running on a physical AutoRally platform, make sure the platform is set to autonomous control and autonomous motion is enabled. If you are unsure what that means, refer to the AutoRally Operating Procedures

  • Launch the waypoint follower with the platform stationary

      roslaunch autorally_control waypointFollower.launch

alt text The waypointFollower does not control the throttle. You can control the throttle manually, run the provided Constant Speed controller, or use your own controller.

Some waypoint details

On startup the waypointFollower reads in the waypoints file as an ordered list, and steers toward the first waypoint in the list. When proximity conditions are satisfied for a waypoint, the controller moved on to the next waypoint in the list. The waypointFollower loops back to the first waypoint once the proximity conditions for the last waypoint in the list are satisfied.

Launch parameters WaypointRadius and HeadingP can be tuned to change the reaction speed of the steering and how close you must get to a waypoint before switching to the next waypoint.

Record Waypoints

alt text The waypoint follower automatically loops back to the first waypoint in the list after the last is reached. To produce the most reliable waypoint following behavior we recommended you set the first waypoint at the end of a straight and the last waypoint at the beginning of the same straight.

alt text By default the waypoint recorder will overwrite the provided waypoints file. This behavior can be changed in the waypoint recorder launch file. Remember to update the waypointFollower launch file with your new waypoints file location before running.

Record your own set of waypoints (coordinates in the x-y plane) with the following process:

  • Run some method to control the platform (gamepad in simulation or transmitter in the real world)

  • Run the stateEstimator and ensure it has converged

  • Start recording waypoints with the command:

      roslaunch autorally_control recordWpts.launch

  • Drive the desired trajectory

  • Stop the recordWpts node once you have recorded the desired trajectory to stop waypoint recording.

Some waypoint recording details

The parameter WaypointDistance controls the distance between recorded waypoints.

Clone this wiki locally