Pretraining data?
You can train in stages.
First stage, either digitally generate (synthetic) basic movements, or record basic human recorded movements of a model. The former is probably better and an generate endless variation.
But the model is only trying to control joint angles, position etc. no worries about controlling power. The simulate system has no complications like friction.
The you train with friction, joint viscosity, power deviance from demand based on up, down times, fade, etc.
Then train in a complex simulated environment.
Then train for control.
Etc.
The point being, robotic control is easy to be broken down into small steps of capability.
That massively improves training speed and efficiency, even potentially smaller models.
It is also a fear simpler task by many orders of magnitude to learning the corpus of the written internet.
Comparable to that, would be training an AI to operate with any land, sea or air device. Which, nobody today is trying, (AFAIK)
Eg: https://hub.jhu.edu/2025/07/09/robot-performs-first-realisti...
When we (ZenRobotics) tried this 15 years ago a big problem was the creation of sufficiently high-fidelity simulated worlds. Gathering statistics and modelling the geometry, brittleness, flexibility, surface texture, friction, variable density etc of a sufficiently large variety of objects was harder than gathering data from the real world.
Example of modern physics simulation: https://www.youtube.com/watch?v=7NF3CdXkm68
I believe this is the most popular tool now: https://github.com/google-deepmind/mujoco
AFAICT these have not resulted in any shipping products.