[Nav2] Suggestions around single plan - controller only reactive navigation
Hi!
Reading through some notes and material around nav2 I found a couple of mentions to a navigation setup often referred to as “reactive navigation”, which takes out continuous re-planning from the stack and replaces it for a single plan at the beginning of the navigation that connects the poses to navigate through with minimum cost lines; when there’s no static map those may as well be just straight lines.
I’m currently working on a robot that ought to work in large outdoors suburban-like environments navigating through sidewalks of different widths: some of them may barely fit the robot but are not usually populated with obstacles, while others are very wide but are very frequently populated with people moving around the robot.
I tried to set up this “reactive navigation” style on a simulated world with no static map using the DWB controller and an 8x8m local costmap, however, despite lowering the scale of the path-related critics and raising the obstacle-related, I struggled a lot to to make the robot go around even static objects that were in the way marked by the initial “straight line plan”. These obstacles would have been easily dodged by a navigation system using continuous replanning, as they would have been marked in the global costmap and the path for the controller to follow would have accounted for them. However it is not possible to mark them in a “static layer” beforehand because even though they may be static to the robot, they may be there just temporarily (ex: a parked car slightly blocking the sidewalk).
Has anyone had experience with this setup of the navigation stack? How did you set up your critics? Are there any guidelines for tuning the DWB controller for achieving a good balance between obstacle avoidance and path following? I expect the controller to dodge obstacles of all sizes, from a football ball to a full golf-car parked on the sidewalk or a big group of people the robot cannot go through, meaning it would have to be able to go pretty far away from the “straight line path”.
Do you think this setup would be more suited for dynamic outdoors environments instead of having continuous replanning at a relatively high frequency on a limited window around the robot while having the controller tuned more for path following? What would be the advantages of each approach?
