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Comment by hanniabu | Hacker News Reader

While I was expecting something completely different than what the video showed, it's still pretty damn impressive. Even though this was performed under pretty ideal conditions, it really shows the future potential of what's possible when you have a handful of robots each about a cubic inch able to pull a car. I would like to know how much they were actually pulling though, since it's a bit misleading to say the pulled a 3900lb car. I'd wager it only takes about 75 pounds(give or take) of force. Nonetheless, still impressive.

Edit: just saw it says 200N which another commenter says is about 45 pounds. I'd still say that's pretty sweet for such small trinkets.

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I'm familiar enough with the research on the individual robots (before synchronizing them) to know that these robots are pulling between 1000x and 10000x their own weight. That alone is amazing.

Winches normally lift around ~1,000x their weight if you ignore the cable weight. Considering these don't include the cable's weight and are really slow it's far less impressive than you might think.

Granted, the fist time you see a car lifted off the ground by a dinky 1.5 hp motor it does seem crazy.

The impressive thing (for me, at least) wasn't the "force to weight" ratio, it was the "traction to weight" ratio.

Tractors, bulldozers, etc., are designed to be HEAVY so they can get traction on loose ground. In fact they're designed so the operator can add weight to them in order to get more traction. That these very lightweight objects can get so much friction was truly amazing.

this is probably where "ant" similarity comes into play - the higher number of legs allows for higher traction as for small point of contact traction coefficient may be higher. And thus the synchronicity becomes very important as each one leg can sustain only small traction force.

Well this is roughly one pound of robots using tiny sticky feet. A winch weighs quite a bit and generally connects to something heavy like a tree right? I'm not sure I fully grasp this comparison.

You're thinking specifically of winches mounted on trucks, which is a very narrow application of the device. A winch is just a mechanical setup that uses a gearing system to put a large amount of force on a cable or rope in exchange for turning the gears a relatively large number of rotations. They are used all over the place and don't have to be big at all:

https://en.wikipedia.org/wiki/Winch

Their point was that the winch needs to be mounted to something stable.

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