[ros-users] [Discourse.ros.org] [ROS Projects] Precision Agriculture Simulation with a Quadcopter in Gazebo

[Tahsin Kose]

I haven't recorded yet the version 2 of exploration stack.



All the To-do's from version 1 are implemented mostly.



*  Orientation Fixation is now perfectly handled.

*  Velocity controller produces motion commands according to whole trajectory instead of separate waypoints.

*  2 Frontier approaches. _Closest Valid Frontier_ and _Farthest Valid Frontier_. Both approaches have their own problems. For example, first one suffers being trapped in a sub-region of the volume of interest. Even though the previously explored frontiers and their proximity are checked for to eliminate the problem, it stands still. Latter one suffers a similar problem in fact, which I call as _"Return to Home Problem"_. Since it searches for the farthest frontier, it generally returns back to the starting region and then pushes the true unknown field a little bit. In order to choose between them, I have made several experiments:



All the experiments are made in exactly 10 simulation minutes and the metrics is the explored percentage of volume of the VOI. There are two different configurations. First one is the fast-forward option, in which the candidate frontiers with the same distance are eliminated in one pass. The other one is the meaningful separation between candidate and registered frontiers.



        1.0 Uniqueness Range          No Fast Forward        Fast Forward 

        CVF                               18.55%               19.46%                                      

        FVF                               10.41%               22.50%



        2.0 Uniqueness Range           Fast Forward 

        CVF                               20.709%                                                   

        FVF                               20.314%



Fast forwarding definitely improves the exploration. However, navely increasing the range does not have the same effect on FVF. To be honest, either methods don't possess a crucial supremacy over each other. Much more intelligent algorithms and approaches are required after this point. Version 3 of the exploration will focus on this feature.











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