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Comment by gnicholas | Hacker News Reader

To what extent is this success based on improvements in processing/strategy versus mechanical optimizations? And to what extent is the timing based on starting position? Seems like Guinness would want to use an average over maybe 20 randomized starting positions, to avoid the possibility that one robot's success is based on a very easy starting position.

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They did use relatively lucky scramble. Not pathologically easy but approximately top 3% most lucky scrambles (https://cube20.org/)

This is the visualisation of the scramble and the solution they used:

https://alg.cubing.net/?setup=x2_U_F2_R_L__F2_D_R2_U2_R-__F2...

Few comments on the solution:

They took advantage of the ability to move two parallel faces at once making solution in 14 steps (if you consider Up and Down move at the same time to be only one step).

If they have a double-turn move they ALWAYS turned clockwise.

I noticed the double move toward the end as well, which struck me as smart. What's the importance of the double-turn going clockwise though?

I think it's not important but probably an artifact of a standard notation, where we denote R as a clockwise Right face turn, and R' as anti-clockwise. The 180 turn can be done both ways, but we usually denote it as R2 instead of R2' (even if for human it will be more ergonomic to do a anti-clockwise turn) so the double-turns interpreted literally are double clockwise turns.

Largely mechanical and calibration. As soon as you have the acceleration/torque and timing accuracy you need, the rest is in the calibration. For example, you need to overturn and then backstep for maximum deacceleration and precise landing. This is highly dependent on the type of plastic, wear and tear, and even temperature, which you would need to take into account if this needs to be reliably in an industrial environment. And then there is plastic molding imperfections that could mess with the calibration.

I bet centripetal forces are also quite significant in this case, nearly tearing the cube apart. Good speedcubes are very easy to disassemble accidentally.

The biggest part is probably oiling up the cube so it can actually turn that fast.

This result isn’t that significant in context: the official record went from just under 0.4 seconds to just above 0.3 seconds

I believe mathematically you’re only 20 moves from solving in any sufficiently scrambled position .

Don’t know if they’re controlling for that or not but I suppose if that would matter depends on how far ahead of the previous record this is

Looking at the article it looks like it’s .08 seconds ahead, which taken as a % of total time strikes me as substantial enough as to not much matter. I’m counting 16 moves in the slower video (which was not the WR) but I’m also barely aware of this stuff so I could be wrong.

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