Autonomous Planning

[kamocat]

Have you ever seen an encoder failure?
I was under the impression that if the encoders are physically protected, and if they're wired up correctly, they won't fail.
They should be frictionless, because they are optical (the disk doesn't contact anything but the shaft).
The toughboxes protect them pretty well, as long as there's no dense objects that aren't fastened down.
Are the actually prone to failure?