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Comment by gene-h | Hacker News Reader

Looks like Atlas may have had an accident during filming, there's a hydraulic fluid stain on the floor: https://youtu.be/fn3KWM1kuAw?t=163

And it must also be said that these are preprogrammed maneuvers on a closed course...

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The poses are programmed, but the balance can't be. At least.. if they would be that would be a significant achievement as well I think. So the robots have target poses they should approximate, but how to get there, and without falling over, that's seriously impressive.

Exactly right. SOTA is to continuously solve a trajectory optimization problem in realtime. Probably at a rate of a fews 10’s of milliseconds per solution.

What is SOTA ?

State of the art

state of the art

> there's a hydraulic fluid stain on the floor:

The robot equivalent of performance anxiety.

luckily it doesn't wear pants, that could've been embarrassing

There's a point where you can actually see the robot dripping fluid.

I just wonder to what extent this is pre-programmed. Surely the engineers gave some sort of high level description, and let the robots figure out the rest. Also, it's probably not possible to acount for all the variability of the environment beforehand, so the "recording" played back does not contain every move to the last detail.

They would have specified target trajectories. Then a solver tries to make that happen.

Now that I think about it, all the robots have synchronized trajectories. There has to be some kind of time sync among the robots also.

That answers the recording part, but is this the abstraction the programers use? Setting trajectories manually would be hard to do while keeping them balanced, especially with moves involving legs.

A trajectory is a series of time-stamped poses, specified in world coordinates. As to where they come from, yes you need tooling to keep from going crazy. At Anki, they used animation industry tools, so I am told.

The solver handles the balance part in real time, using current sensor input.

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