Change automatic steering to follow "local" nearest point instead of "global" while following a curve #392
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…"global" while following a curve The previous implementation led the vehicle to sometimes pick a wrong part of a curve when the curve was intersecting itself (AB-curve) or there were more than one parallel lines near to each other (typically occurs when driving along an inner curve formed from a boundary curve and the field's shape is not convex). This changes the curve-following algorithm to use a search for "local" nearest point instead of "global" (= taking all the points on the curve into account) when already following the curve. Look ahead-distance is used when searching the nearest "local" point to prevent problems in tight hairpins caused by the search sticking to a local minimum "on the wrong side" of the hairpin (especially when using large look ahead values causing the vehicle to take a shortcut). Fixes farmerbriantee#391
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(Leaving this PR as a draft, because this is potentially dangerous change. Of course I tried to be careful, but as this is my first time touching this project, it's a real possibility that I forgot something obvious...)
The previous implementation led the vehicle to sometimes pick a wrong part of a curve when the curve was intersecting itself (AB-curve) or there were more than one parallel lines near to each other (typically occurs when driving along an inner curve formed from a boundary curve and the field's shape is not convex).
This changes the curve-following algorithm to use a search for "local" nearest point instead of "global" (= taking all the points on the curve into account) when already following the curve.
Look ahead-distance is used when searching the nearest "local" point to prevent problems in tight hairpins caused by the search sticking to a local minimum "on the wrong side" of the hairpin (especially when using large look ahead values causing the vehicle to take a shortcut).
Videos from testing (about the same conditions as in the issue):
untitled3.mp4
untitled4.mp4
PS: As I now took a look at the code to make these changes, I have to say that I really like the coding style of AOG. Lot of descriptive comments and easy to read overall.