10 part3: Move Base slides |

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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)

Navigating in code

• 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:

• Navigation Wiki Page
• move_base Wiki Page
• Video about navstack
• Paper: Layered Costmaps for Context Sensitive Navigation