The following is an extract from the 4. Path Planning I - Neotic notebook.
When a new goal is received by the move_base node, this goal is immediately sent to the global planner. Then, the global planner is in charge of calculating a safe path in order to arrive at that goal pose. This path is calculated before the robot starts moving, so it will not take into account the readings that the robot sensors are doing while moving.
Each time a new path is planned by the global planner, this path is published into the /plan topic. Let’s do an exercise to check this.
I couldn’t find any topic named /plan in the rostopic list, my my_move_base.launch file is up and running, I can use Rviz to send goals and the robot is working just fine.
I believe the “/plan” mentioned in the notebook has to be replaced by “/move_base/DWAPlannerROS/global_plan” or the “/move_base/NavfnROS/plan” depending on what was selected in the launch file.
Please let me if I have something wrong on my side.