avt_341_global_path_node

Global Path Node

The global path node publishes a set of user-defined waypoints that are used by the local planner as the desired center-line for the local path.

The waypoints are provided in a YAML file, which must be loaded by the ROS parameter server when the simulation is run. Performance of the local planner will be optimal if the waypoints are spaced 0.5-2.5 meters.

The global path node also monitors the vehicle odometry to check when the simulation is complete. When the vehicle reaches the final waypoint, the vehicle will behave according the desired shutdown behavior, enumerated below.

Subuscribed Topics

• avt_341/odometry (nav_msgs/Odometry) Vehicle odometry from real-time-kinematic or other localization sensor.

Published Topics

• avt_341/global_path (nav_msgs/Path) Global path defined by user as waypoints in East-North-Up coordinates.
• avt_341/current_waypoint (std_msgs/Int32) ID number of the current waypoint.
• avt_341/distance_to_current_waypoint (std_msgs/Float64) Lateral distance to the current waypoint in meters.
• avt_341/state (std_msgs/Int32) The current simulation state, which can be -1, 0, 1, 2, 3
  • -1: Idling in startup state - no waypoints loaded or recieved
  • 0: Active - following waypoint path
  • 1: Idling in end state - bring vehicle to a smooth stop after reaching the final waypoint in the current path
  • 2: Shutting down - ROS network exits after bringing to a smooth shutdown
  • 3: Emergency shutdown - sends braking message and shuts down.

Parameters

• waypoints_x ([double]) X-coordinates of the waypoints list, in local ENU coordinates.
• waypoints_y ([double]) Y-coordinates of the waypoints list, in local ENU coordinates.
• ~goal_dist (double, default: 3.0) The minimum distance from the final goal the vehicle must reach to complete the simulation, in meters.
• ~global_lookahead (double, default: 50.0) The distance beyond the vehicle which the global path planner will consider.
• ~shutdown_behavior (int, default: 1) Indicates the desired behavior when the vehicle reaches its final goal point. The value can be 1, 2, or 3.
  • 1: Bring to a smooth stop but do not shut down
  • 2: Bring to a smooth stop and shut down
  • 3: ring to an immediate stop (hard braking) and shut down
• ~display (string) Can be "x11", "rviz", or "opencv". Only "x11" and "rviz" are available in ROS1, while only "opencv" and "rviz" are available in ROS2.