10 part3: Move Base slides |

Looking inside move base

Behind the scenes

  • amcl subscribes to a topic geometry_msgs/PoseWith
  • rviz command 2d pose estimate publishes the new proposed pose on that topic
  • When amcl receives that message it resets its collection of candidate poses

Going inside the Nav Stack

  • Global planner: works out best path assuming map is accurate
    1. global costmap: How safe or unsafe is each spot on the map
    2. Published on /move_base/global_costmap/costmap
    3. Planner view shows what the planned path to the nav goal is
  • Local Planner:
    1. Adjusts the global plan based on newly detected obstacles
    2. Map shows square area around robot with further analysis 1 Color shows safe areas in cold colors (like blue) and dangerous areas in warm colors (like red)
  • Look at patrol.py
  • It is a SimpleActionClient which sends a repeating sequence of two Action Goals to move_base
  • There’s nothing tricky about itself.
  • The challenge might be getting all the other bits set up so that it will work correctly

Some more references: