LUBA 3 and 2X: a thin post slips between the bumper and the front wheel and traps the mower

What owners report

• A LUBA 3 on firmware .26 had worked around a stop-sign post all summer, then got caught on it. Its owner writes that nothing in the app settings changed¹. Other owners in that thread say theirs has been catching on poles and signs, one for the last year, and another that it went over a rock wall and stuck on top¹.
• Several owners recognise the same gap. One writes that anything of that diameter will get stuck behind a LUBA's front wheel sooner or later¹. Another writes that a thin vertical object slipping between the bumper and front wheel has been possible for a while².
• A LUBA 2X gets a metal fence post between its bumper and body, not for the first time, and took five minutes to free from the fence. It happens every week³.
• One owner of three years says it has happened to them about three times in that time, each when the gap around a tree support was a little tight and the mower turned at the wrong moment².
• When it happens, an owner describes the mower rocking forwards and back while it pivots on the post and digs². Another says it broke their bumper that way².
• Not everyone has it. A LUBA 3 owner says thin metal trampoline poles are the only thing that trips theirs, and a no-go zone fixes that⁴.

Why owners think it happens

One owner who has had it explains it as the mower turning "through" the object so it slips between the bumper and the wheel. They say the camera's field of view is too narrow to see the object before it happens, that there is no sensor at the back of the bumper to register the hit, and they guess that the mower does not count itself as stuck because it still moves a little². That is one owner's reading, not Mammotion's. Another owner calls it a design flaw because the bumper only feels the front².

Owners disagree on whether it is new. One says it has always been present and has not got worse². The owner who started the first thread blames the updates since July¹.

What Mammotion says

• Keep clearance and mark it. On a photo of a mower caught on a metal support, a Mammotion account wrote that the space left very little room for the LUBA to turn, so the front of the mower can be blocked by the support. It recommended keeping some clearance when planning the mowing area, and defining the fixed support as a restricted area on the map rather than relying on the front bumper or the vision system to steer around it².
• Obstacle mode. To the owner who started the first thread, an account asked which obstacle avoidance mode was in use and whether switching to Sensitive improved things. It also asked whether they had uploaded logs¹.

What owners put on posts

• A pool noodle, a tree protector or foam pipe insulation on the thin vertical. This is the most common answer¹². One owner says to wrap tape around the pole¹.
• A restricted area around the post. Owners say mapping posts and trees as no-go zones works for them, and one says a virtual fence helps when it sticks in the same place¹³⁴.
• Guard rails bought for the front wheels. One owner says 3D-printed ones do not last².
• Paint. One owner suggests painting the lower 8 inches of a post flat black, or taping paper to it, to see whether the mower then sees it. That is a suggestion, not a result³.

What is not known

No source here says the mower's software or hardware changed to cause it. The restricted area is the step Mammotion's own account gives. How much clearance is enough is not stated.

A LUBA 2 AWD X that drives into a no-go zone and sticks against a tree is a different report, on its own page.