Robert Playter

If something else happens, you better start predicting again.

You know, there's a few different layers of that.

You want, at the lowest level, you like to run things typically at around 1,000 hertz, which means that, you know, at each joint of the robot, you're measuring position or force and then trying to control your actuator, whether it's a hydraulic or electric motor, trying to control the force coming out of that actuator.

And you want to do that really fast, something like 1,000 hertz.

And that means you can't have too much calculation going on at that joint.

But that's pretty manageable these days, and it's fairly common.

And then there's another layer that you're probably calculating maybe at 100 hertz, maybe 10 times slower, which is now starting to look at the overall body motion and thinking about the larger physics of the robot.

And then there's yet another loop that's probably happening a little bit slower, which is where you start to bring your perception and your vision and things like that.

And so you need to run all of these loops sort of simultaneously.

You do have to manage your computer time so that you can squeeze in all the calculations you need in real time in a very consistent way.

And the amount of calculation we can do is increasing as computers get better, which means we can start to do more sophisticated calculations.

I can have a more complex model doing my forward prediction, and that might allow me to do even better predictions as I get better and better.

And it used to be, again, 10 years ago,

We had to have pretty simple models that we were running at those fast rates because the computers weren't as capable about calculating forward with a sophisticated model.

But as computation gets better, we can do more of that.

Is there a nice pipeline?

It's an important part of building a team around it, which means, you know,

You need to also have software tools, simulation tools.

So we have always made strong use of physics-based simulation tools to do some of this calculation, basically test it in simulation before you put it on the robot.

But you also want the same code that you're running in simulation to be the same code you're running on the hardware.