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.
The the deck is capable of moving a lot faster than you can move.
So so we could pull your feet out from under you if we ever, you know, had it set to do so.
So all the algorithms stuff will will have more to do with other variables,
like your CG, CG imbalance.
And there's a moment arm between the distance from my feet to where my CG is, right?
So, so the acceleration that you put there, there's gonna be this lag time in my brain where I try to counteract that, is that correct?
Very much.
All right, this is the part of video where I tell you about the sponsor and, you know, a lot of people fast-forward through this part,
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Thank you for considering that.  Last thing. I wanna say thanks to the guys at Infinadeck.
A treadmill made of treadmills, that is insane.
You're there man, this is just a control systems problem at this point, isn't it?
We just need some control engineers.  We ought to hire a couple.
That's what this is at this point.
At this point, it's just computer stuff and math so this is doable
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That's completely okay. Anyway, I'm Destin. You're getting Smarter Every Day. Have a good one. Thanks for learning with me
You're gonna fall. You fell. You jumped. Whatever. What are you doin'? Why you makin' noise?
