Waypoint Follower

In order to drive along the planned driving path consisting of waypoints with associated target speeds and yaw angles, an implementation of the Pure Pursuit algorithm is used.

This algorithm receives the upcoming waypoints from Waypoint Updater and publishes a target linear velocity and angular velocity for DBW Node to control throttle/brake and steering actuators.

Pure Pursuit Algorithm Overview

• Pure Pursuit Geometric Description

Autoware Open-source Pure Pursuit Library (Waypoint Follower)

• Autoware Open-source Libraries

Project Improvements Made to Waypoint Follower Library

• Tune verifyFollowing() judgment thresholds for distance displacement_threshold_ and relative angle relative_angle_threshold_ to keep more continuous steering adjustments to prevent ping-ponging around target path.

• Perform closest waypoint search to pick up the correct waypoint speed targets when the car has driven past the initial waypoints in the list (in case of lag or Waypoint Follower updating at a faster rate than Waypoint Updater).

• Perform look-ahead waypoint search starting from closest waypoint instead of initial waypoint in the list to prevent searching behind the car when some waypoints remain behind the car.

• Tune minimum_lookahead_distance_ to be able to steer around tighter turns such as the Udacity test lot.