[MUSIC PLAYING]
All right.
So I'm Saul Griffith.
I work at a little lab called Otherlab.
We have too much fun, as you'll find out shortly.
I'm actually going to talk today about going soft, which
is going to be an elaborate discussion of why this is the
past of engineering.
So this is a rigid, many pieces, many mechanisms to try
and do that.
And that the future of engineering is actually this
amazing device, which is the only example of soft
engineering that I have yet found.
Which is, instead of lots of complexity and lots of parts,
it's one part--
shoots further.
I'll hand these around.
And the rest of the talk is just to justify bringing those
two guns to the table.
So how did this-- my interest in engineer soft as been
longstanding.
For no particular reason, I've had a fascination with
building inflatable objects, including things like
inflatable dinosaurs and elephants.
And I gave that elephant that you just saw
to this young lady.
And this is in fact, the X that I am solving for.
Because I gave her this sort of rigid, inflatable elephant,
and she said, that's great Uncle Saul.
This young lady's name is Emily.
She's my niece.
And she said, yes Uncle Sol, that's great, but I would like
to ride my elephant to school.
Can you make it walk?
And I'd never really thought about it.
So we built this.
Well actually, I had my sister send back the elephant.
We simulated whether it was possible in doing and making
some newer types of fluidic muscles, could we make this
thing walk.
And sure enough, here is Stumpy taking its first steps.
It can move at the astonishing speed of one
mile every eight days.
[LAUGHTER]
Which incidentally, Emily thinks is perfect
for riding to school.
So that's really how it all began.
This was the next robot we built, because indeed, you
have to test these things on your children.
So this is my son, Huxley.
The helmet is really just because I knew his
grandmothers were going to watch the video.
And he's riding an actual first rideable, walking robot.
So what's amazing about this is--
the history of mechanical engineering and design, and in
fact, every artifact around us is-- we pretty much only make
stiff, rigid, hard things.
And to give movement, we have bearings and all that.
This is just sewn.
There is no hinges.
There's no bearings.
There is really no mechanism.
If you deflate it, it's a pile of fabric.
So I guess what I'm--
this is sort of the--
I'm only going to show one equation, because you lose at
least half the audience each time you do.
I'm going to make the argument, engineering has been
prisoner to this.
This is Hooke's Law, which states, this is basically the
stress-strain relationship, that we want to be linear.
And so you've been prisoners since then.
These curves here-- we can plot these curves for all
manner of materials and to a certain extent, mechanisms.
And all engineering throughout all of history has pretty much
been constrained to using this nice linear approximation,
where we can understand materials
as rigid and linear--
and mechanisms.
And I guess, I'm fascinated with the enormous green fields
of what we can do and what we can build, if we engineer with
things outside that linear constraint.
And we sort of learn how to engineer soft.
This is a fabulous example from biology-- all the soft
things are from biology.
So this is a puffer fish.
And in fact, it redefines stress-strain curves
completely.
If you look, this is the stress-strain curve for a
puffer fish, way over there on the right.
This is highly nonlinear and very different
to any other material.
And it gives these fish the amazing capacity to change
shape so extraordinarily.
So to try and tie this to moonshots, I like to think of
the artifacts of the moonshot.
If you're sufficiently ambitious, you have to develop
new materials, new mechanisms, new design tools, new control
systems, and even new destinations.
And they are sort of the artifacts of a moonshot.
And I think the reason I'm fascinated with this going
after soft engineering is, we're going to have all of
these artifacts of that moonshot.
And they're going to change our lives in all sorts of
fabulous ways.
So this is a little video from the
Whitesides Group at Harvard.
This is just to show that I'm not the only fruit loop in the
world thinking about this stuff.
This is a fabulous, much-smaller scale, and subtly
different mechanisms--
extremely elastic group.
This is picking up an uncooked egg, which is a traditionally
very difficult thing for a robot to do.
And this is a beautiful demonstration of some of the
unique capacities that we can do if we
start to engineer soft.
So here's a walking gait of the little
rubber robot, I guess.
Comes up against a glass ceiling.
And now, can completely change gait and go under it.
So these mechanisms are great at the smaller scale than sort
of the inflatable things that we're doing at big scales.
All of these things, we're still in so early in this
engineering of soft things, that we're just sort of
establishing what is possible at the moment, and what the
new design means are.
So one insight of soft things that I want everyone to
understand, is soft things can do unique things.
And they can do things just as well or even
better as hard things.
So this is a bluefin tuna, one of the most astounding and
fast swimming of all the fish.
It achieves that speed by having a very long tail, and
then a very tall tail, which is actually a wing.
It's a very high-aspect ratio, very efficient wing, that it
can beat with all the muscles down the back, to propel
itself very quickly.
The forces on that wing at the rear are extreme.
So it has, in fact, a very bony tail wing.
And that stiffness and rigidity of that enables that
tail to not buckle at high speed.
This is the shark that evolutionarily diverged from
the tuna 400 million years ago.
It is made of cartilage, and we never really understood how
could the shark swim, in fact, faster than the tuna, as it
does, when it has no rigid elements in the tail.
So the body and particularly the tail, that wing surface,
should buckle under all the incredible load.
It turns out what the shark does, is it has a
whole lot of advanced--
it's an extremely advanced fiber composite.
So it has all these fibers actually all over its body,
but particularly in the tail.
And then it pressurizes the various aspects of it.
So inflates itself, puts these things under tension, and in
fact makes a structure that is lighter per weight and stiffer
than the bony structure of the tuna.
What's incredible is another feature of soft things if we
wanted to engineer them, the shark actually has a very,
large dynamic range, because it changes the
pressure of its stiffness.
So at high speeds, it's highly pressurized to go super fast.
At low speeds, it depressurizes, so it's
extremely maneuverable.
Just because I promised to, this is an armadillo penis,
which for some reason, is how we're trying to learn to
understand these things.
Some scientists are trying to figure out how
these things work.
So there was the problem of the penis, or the mystery was,
it should buckle under the loads that it is exerted to.
How does it survive it?
And you can actually see in cross section, we're starting
to understand, again by pressurizing
fibers that are oriented--
in this case collagen fibers-- that are oriented in the
correct fashion, we can get extreme stiffness and prevent
buckling and other loads, and have again, machines that have
sort of large dynamic range of capacities.
So why is now the right time to do soft engineering, where
it wasn't previously?
I think we finally have enough compute to simulate and design
and control these things.
We're starting to get the senses that enable us to
control these things.
There are new materials, new textile technologies, and new
elastomers.
So I think we are now ready to go.
These things can do--
Here's the ant roach, as we call it--
half cockroach, half anteater.
We're doing proportional control, so we can actually
have quite high precision with the nose there.
And then here it is doing a walking gait.
This guy can now walk at one or two miles an hour.
And then, we're building a platform this year that will
hopefully do 10 or 20 miles an hour.
The amazing thing about this robot you're seeing is, it
weighs about 50 pounds, and can in fact support a very
large load.
So there's two adults and two children riding that thing.
So in terms of strength-to-weight ratio with
these types of machines, we can expect as much as 10 or
1,000 times the traditional machines.
Soft will mean lighter weight, which can mean lower costs.
These mechanisms can be more efficient.
They can be more resilient to damage, high-dynamic range.
They can be tunable.
And they're going to enable entirely new applications.
I'm fascinated with doing this, and not just fill them
with air for terrestrial applications.
This would be a tremendous way to do deep-sea exploration.
If it's filled with water, it can be at the same pressure as
the sea below it, so it won't suffer a lot of the problems
of traditional submarines.
And then because of the elasticity and the design of
the mechanisms, we can actually do much better.
This graph really sort of shows you that you can expect,
if you can operate these elastic machines at resonant
frequencies, much higher mechanical efficiency--
go longer while we're down there.
There's another insight here.
This compliance can be substituted for mass.
Human engineers, we solve all problems by adding more steel,
more concrete, more plastic, and make things more rigid to
prevent damage.
Biology solves these problems with compliance.
Trees survive storms better than telegraph poles, because
the trees can change shape.
They can share the wind loads.
So I think we need to start applying those types of
insights to how we engineer things.
Here is a comical example of that.
This is actually an inflatable car that we built--
really just because you can.
And then basically it's an electrified, wearable air bag.
You can actually roll this thing and land sunny side up,
and keep going.
But then one of the features of these things is, you can
crash this all day, and you do.
It's actually the most fun thing to do with that
inflatable car.
So just a dream about the application space.
I'm really interested in prosthetics.
This is not a prosthetic.
Well, it sort of is a prosthetic,
but it's just a brace.
But we now actually have very crude prototypes of making
soft exoskeletons-- you might call them exodermises--
that you can actuate.
And we could use these for doing fabulous things, like
giving able-bodied people superhuman strength.
Or we're looking at helping stroke victims and spinal cord
injuries to remediate.
So I'm fascinated with those applications.
I think in an aging population, actually wearable,
soft external muscles, so that 70-year-olds can play tennis
like they were still 20, would be a fabulous application.
To just quickly go to another fabulous, soft machine.
This is the heart.
We've just recently learned that the heart is in fact a
linear thing, tied in a knot.
And here is an example of a soft machine that's fabulous.
It's a pump with huge dynamic range.
And just by sort of twisting backwards and forwards,
sending a wave down that stream that is tied in a knot,
we get our pumping.
We're now starting to experiment.
So this is a soft pump that we're using to hydraulically
drive one of their prosthetics.
And this is going to give us a thousand-fold increase in
strength or in power, again to go to hydraulics or
pneumatics.
I think it's going to be a fabulous way to add strength
to these machines.
I think Rodney Brooks said it yesterday fabulously.
We have to expect to have more robots sharing our
environment with us.
So they need to be human safe.
And there's some beautiful, natural compliance in human
safety about these robots.
Fascinated with that.
And then just maybe, one of the other-- this is another
type that we've been experimenting with.
And one of the fabulous things about the strength-to-weight
ratio, these robots can be extremely light, and then
consequently can be incredibly fast, because they have very
little inertia.
So, also intrigued with applications where that type
of speed is interesting.
Obviously, super hard-- we have to bring
them under the control.
And you probably guessed, we haven't done a
great job of that yet.
Although, as we were talking about smiley faces yesterday,
we can in fact draw a smiley face.
This is with this thing now.
So slowly getting it under control.
So I think the soft engineering can and will
revolutionize prosthetics, robotics, our human machine
interactions--
just mechanical design across the board.
I think what it enables in exploration of space and
undersea, in and of itself, justifies doing this.
For medical devices, and just for toys and because you can
for delighting six-year-old nieces, we should do this.
And then I think, this is the really--
I actually brought this robot here.
I hope you will come and shake its hand.
I think the really compelling moment of these machines is
when you actually shake its hand.
And it feels much more human than any other machine you've
ever touched.
So I think this moment is the "aha" moment.
Just quickly in wrapping up, what's next is bringing these
things under control, finding fabrication
techniques to make them.
Simulation in the loop, so that we can
design these things.
There is no CAD tool called soft works.
Everything's solid works, and rigid.
So we need new design tools.
And then super exciting to me is, this is Manu Prakash's
work at Stanford.
He's re-invigorating the field of fluidic computation.
So while we have these fluidics on these things, we
can do integrated computation, integrated actuation,
integrated control--
which would be fabulous.
This is actually fluidic logic from the '70s.
You can even do combustion inside these chambers.
So we could further increase the capacity of these things
by actuating them in their skins.
And then this is wonderful work by Rebecca Kramer, who
was out of the Whitesides Group doing soft senses.
And now, we will actually be able to do a fabulous
proprioception with the entire skin senses
coupled to these robots.
So by moonshot standards, this is going to be cheap.
Just really what's hot here is changing the way we think
about designing machines, and raising a generation to
consider soft, as well as hard.
Soft is cuddly.
Soft is good.
Thanks very much.
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