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  • Hey, it's me, Destin. Welcome back to Smarter Every Day. A treadmill is a pretty simple device, right?

  • You set the speed you want; you get on, you start moving.

  • But you don't actually go anywhere. This technology people have realized for a really long time is perfect for virtual reality

  • Because you could walk somewhere and actually use your body but not leave the confines of your own home

  • Okay here we are in California. We are at a company called Infinadeck. This is a small engineering outfit

  • These guys make a 360 degree treadmill the one that's in the movie ready player one so the interesting thing is they're really small company

  • But they've got a really cool idea, so let's go check out how this thing works.

  • All right, so this is George, and he owns Infinadeck right?

  • Yeah

  • All right

  • And basically Infinadeck is a 360 degree treadmill technique. That is

  • Is it safe to say that we've got treadmills on top of treadmills here?

  • It's a treadmill made of treadmills

  • Okay. Treadmill made of treadmills

  • So you can think of it as you've got one axis of rotation here and each individual

  • Treadmill can move in this direction as well, right?

  • Yeah

  • So how do you ?

  • So it's a combination right obviously if you want to go X. This is our X direction. This is our Y

  • X is nothing, but a treadmill you know like any other treadmill the Y it's nothing, but the smaller treadmills

  • right now we're using the Vive tracker on you

  • Right, so where is the, there they are right there.

  • So your tracker's on your rear

  • We kind of artificially take you about

  • seven or eight inches in front of that to get the middle of your CG

  • And this tries to keep that middle of the CG in the middle of the treadmill right there.

  • Oh I got you. So the, so the feedb-

  • that was one of my main questions is what is the feedback loop? It's a positional feedback loop.

  • Yeah, it's fairly simple right now. We're making it better this that's the part

  • We're gonna just keep improving for ever, years and years and years

  • really? so the goal so you have an object and then

  • Oh, I get it. It's this is, this is called

  • They're very visual

  • This is a semi autonomous command position sensor. That's the best

  • Specific way to say that, right?

  • Now what we're also doing on this one is

  • You put foot trackers on when you combine the foot trackers the headset and your and your hand controllers

  • You now have six different

  • Points that is tracked on you, and that's enough for us to give you an avatar

  • George Jr told me if I screwed this little VR tracker into the bottom of the camera

  • We can insert that camera into the virtual world

  • Which of course we had to do

  • So we're ready?

  • Yeah

  • So I just I just get in?

  • Yeah go ahead, so

  • Alright

  • Let me help you a little

  • Okay? So first let's do your feet

  • Alright

  • This is the CG you're gonna put that on.

  • Make the tracker meet like directly behind your back

  • Okay

  • So go on, put your headset

  • This feels like I'm actually getting in the Oasis here

  • Oh wow I can see the camera, in the virtual world

  • If you look towards me you should see the two controllers?

  • What the heck man!

  • So we're gonna have you do now

  • Okay, okay. I'm trying to. This is just normal VR.

  • So I can actually see the ring now

  • That's something I didn't expect, so I can, it's there

  • Yeah

  • Alright so now that's

  • I see my body too - what's up with my body

  • So we're gonna sync that with you.

  • So if I can have you stand with your legs straight down,

  • and your arms straight out to your sides, like a T-pose?

  • Three two one

  • Did it work?

  • Oh I can see my body!

  • Wow

  • Alright

  • Okay, that's rad. That's really rad.

  • Okay, gotcha so

  • So right now you're tracking the position of my hands and my feet

  • Dude that is messed up! This - I'd like him - Alright

  • So I can see the camera, the tic-tac there, but what's more important is I can also see this ring

  • And Griffin why did you say you have this ring in here?

  • So this is there to kind of lock you down in the real world without being too much of a burden to say

  • So this is like you know when you do an integral you get the plus C at the end

  • So this is a boundary condition for me to kind of lock my brain into both worlds

  • so this is like this tells me where I'm at virtually and

  • Like actual my body, right?

  • Absolutely

  • Okay so, are you ready to start walking?

  • I'm ready to start walking

  • We're gonna recommend you have your hands on the range when you first try this just so you get used to

  • That's okay, so when you start. Yeah. I thought it would make sense for you for it to put me in the center, okay

  • So now right?

  • What is trying to do is this trying to keep the CG of my back in the center of the ring, right?

  • So I'm gonna touch this and as I walk

  • Okay, it takes just okay. I'm there. Okay. I don't want to hit that tree

  • So I'm gonna turn this way

  • Okay

  • So I can't really tell if I'm walking 90 degrees or not

  • Okay, so there's inertia in the rollers, okay? I thought there might be. So if I move backwards

  • It's gonna keep me there I move forwards

  • So it takes just a second

  • Just a couple seconds on the Infinadeck, and I instantly understood the problems that these guys have to overcome

  • It's pretty interesting

  • It seems pretty simple: whatever direction a person walks, the Infinadeck moves in the opposite direction, whether it be X or Y, at

  • the exact same velocity and acceleration. Think about a normal treadmill: your brain is doing all the processing. Your brain is constantly

  • Solving the equation a treadmill velocity plus body velocity equals zero if at any point

  • You don't solve that equation correctly you start moving relative to the treadmill. This is a very similar problem, but it's much harder

  • It's harder because there's two dimensions

  • That's the obvious one

  • But it's also harder because the processing isn't happening in your brain. That processing is offloaded to the Infinadeck

  • which, oh by the way, can't read your mind.

  • There's a delay time for the Infinadeck to figure out where your position is and try to change that...

  • Yeah. Yes.

  • ...and if it tries to

  • do it too quickly you know you can have an overdamped and under damped system is that correct? Yeah.

  • Is that the right terminology?

  • So, yeah

  • So at the moment what we're currently doing we're trying to make it so that the acceleration on the user in

  • any way that they're not really tried experience is never more than 0.1 Gs got it

  • Oh that seems to be about a good amount to not really be, you know disturbing for the user. Okay.

  • We're trying to figure out where exactly that isn't how to do that if I walk forward

  • I'm gonna feel an acceleration in one direction on my body because I'm pushing against the floor, right

  • but then the floor is gonna move, and it's gonna move my body in the opposite direction, so I'm going to feel an

  • acceleration that's negative, which is strange for, you know, a normal walking around human. Then, once I hit a steady state velocity,

  • I'm gonna level out that acceleration in my mouth. My body's gonna be cool with it right, but the moment I stop

  • That's a change in velocity and the Infinadeck has to accommodate for that. It has to move you back to the center

  • gracefully and one thing that happens is if it tries to move you back too fast

  • It'll overshoot, and then it has to correct. So this is a really interesting engineering

  • problem because it doesn't have

  • perfect knowledge of intent. Like, that

  • that's the difference with your brain you have intent and so when you're walking in a normal treadmill you get to

  • choose everything, right?

  • but you have to understand over the last few years

  • we had to, you know, build and modify the Infinadeck too

  • along with the control system, and there's only a few of us, so. Well. It's been challenging all around.

  • This is why the problem is interesting because when you're walking in the world

  • Right now my acceleration is zero

  • And then when I stop I'm used to imparting acceleration to my body

  • But that doesn't happen till later

  • Yes, it's a work in progress how far you go back. It's

  • That's clever. That's it's a challenge. That's a that's a hard math problem one thing

  • I thought was really cool is you can use this to be a different size in the virtual world just by changing a

  • Constant right you can scale

  • How many steps it takes to get around in the earth?

  • Just by a scale factor, but literally a scaler, that's often. Oh, there's the same boat look at that

  • It's a dude. It's like

  • I want to jump

  • I'm just

  • Too small to get it

  • Too small to go to my boat and *laughs*

  • That's fun. That's really fun that the model... There's my bench. Look behind you, there's my bench before

  • In engineering we have these assignments called technology readiness levels

  • There's nine of them, and I would say this is somewhere between a six and a seven

  • Which means there's a working prototype that works, and they're just refining the subsystems they're about to go to production

  • So it's really cool to be able to walk on

  • This Infinadeck before it goes out into mainstream production and see the behind the scenes engineering things

  • they're having to solve. It's really interesting. So, it's clear George knows all this

  • I mean he instantly understands all the variables I asked him about

  • That how tall the person was like if you think about it your center of mass is at a different length and so that moment

  • arm is different you have to deal with inertia differently like from the bottom of it. It's really interesting anyway

  • This is me talking to George and you can tell he totally gets it. I I can imagine that the

  • the inertia

  • Overcoming that inertia is different for each person because if I'm 175 pounds and I move here

  • It takes a certain amount of torque

  • I'll cut the deck off now. It takes a certain amount of torque for these motors to move me and

  • That's going to change based on the size of the person, is that correct?

  • That's correct that. It's more about your acceleration than the inertia.