Researchers simulate a quadruped robot crossing a balance beam

Since we have machine-learning based walking models for several years now, see e.g. [1] or [2], I'm wondering why walking isn't yet a solved problem by now (?)

[1] https://www.youtube.com/watch?v=pgaEE27nsQw

[2] http://mrl.snu.ac.kr/research/ProjectScalable/Page.htm

One can imagine robot gurneys whisking the injured to hospitals.

...in simulation.

Though it sounds like they're getting closer to having it work in vivo. Looking forwards to that video.

Ok, we've made the title be a simulation above.