LUBA 2: slides onto adjacent surfaces when turning on a slope near a boundary

The pattern

On a mowing zone that includes both a slope and a hard boundary (a road, path, or flower bed) close by, LUBA 2 slides onto that adjacent surface while turning at the edge of the slope, rather than turning cleanly and staying on the grass. A buffer of over a meter from the road was needed to keep the mower reliably on the lawn in one case¹.

The mower's front wheels have no lateral (side-to-side) guidance — a geometry limitation, not something firmware can fix — which also causes trouble mowing parallel to a slope (only up/down works cleanly), with visible wear at the turning points at the bottom of each pass, per a second owner¹. A third owner confirms the identical pattern, including the same difficulty keeping a clean line around an obstacle placed on the slope¹.

What helped, and what didn't

Increasing "patrol rounds" (PR) to 4 worked for one owner, but not another. Running 4 patrol-round passes around the mow zone before regular mowing starts (rather than the default lower count) makes those passes happen across the slope rather than up/down it, and keeps the mower's regular mowing pattern afterward a full two mowing-widths back from the boundary, eliminating the slide entirely — confirmed over repeated mows by a fourth owner¹. The same setting produced no improvement for the first owner: the mower's "black lines" (the paths it actually drives) stayed identical regardless of patrol-round count, still running to the same boundary-hugging edge¹. Neither owner could explain the difference in outcome. Worth trying on your own setup, but don't assume it will work.

A separate, narrow mow zone parallel to the slope is the one workaround with no reported downside: define the sloped strip near your boundary as its own mowing zone so the mower drives back and forth across the slope (parallel to the boundary) instead of turning on it¹.

A wider manual turn radius plus hand-trimming is a third owner's fallback: increase the turning radius setting so LUBA 2 turns further from the point/edge, and hand-trim whatever strip that leaves ungrazed¹.