This GPS works very well as long as the canopy does not interfere with the operation of the GPS.
So I decided to add a LIDAR to be able to locate when the GPS no longer works. The LIDAR will locate itself in the orchard thanks to the trunks of the trees. The robot moves slowly (3 meters per minute).
The LIDAR that I think is suitable for outdoor use is RPLIDAR S1. Unfortunately, its angular resolution (0.4°) seems too weak to pinpoint trunks of small diameter. I wish I had a better angular resolution than 0.1°.
To do this, it would have to be possible to decrease its scanning frequency to less than 2 Hz, whereas its minimum scanning frequency of RPLIDAR S1 is 8Hz.
Is this possible? Can we ask the manufacturer for an option?
As far as I know reducing this much may not be possible. Also, it should be noted that the equipment in the sensor that determines angular position also has a limit to its resolution and accuracy: it may not be able to get any better than the stated minimum.
AS for detecting smaller objects, while one scan may miss it you have to also account for the fact that SLAM is built upon the statistical analysis of dozens if not hundreds of scans to make sure to get a grasp of the room and landmarks. Therefore, since your robot is pretty slow (0.05 m/s) you’ll most likely be able to obtain much data.
The best would be to contact the manufacturer directly. You can do so here.
Alternatively, you may want instead to use a combination of wheel encoders (which you should already have for any mobile robot that needs localization anyway! ) and a stereo vision system to detect objects and depth (see VSLAM).
I confirm that it is not possible to decrease the scanning speed according to the manufacturer.
Nevertheless, I have done some simulations that show me that the S1 RPLIIDAR is usable. So I am considering ordering it.
As for the wheel encoders, I don’t think they can fit because of the inequalities of the terrain, because I have to cover a 100-metre route without GPS…… But I’ll think about it anyway!
I will continue my project when the coronavirus containment period is complete…
) and a stereo vision system to detect objects and depth (see