Why I make robots the size of a grain of rice

My students and I
work on very tiny robots.

Now, you can think of these
as robotic versions

of something that you're all
very familiar with: an ant.

Right? We all know that ants
and other insects at this size scale

can do some pretty incredible things.

We've all seen a group of ants,
or some version of that,

carting off your potato chip at a picnic,
for example, right?

But what are the real challenges
of engineering these ants?

Well, first of all, how do we get
the capabilities of an ant

in a robot at the same size scale?

Well, first we need to figure out
how to make them move

when they're so small.

We need mechanisms like legs
and efficient motors

in order to support that locomotion,

and we need the sensors,
power, and control

in order to pull everything together
in a semi-intelligent ant robot. Right?

And finally, to make
these things really functional,

we want a lot of them working together

in order to do bigger things.

So I'll start with mobility.

Insects move around amazingly well.

This video is from UC Berkeley.

It shows a cockroach moving
over incredibly rough terrain

without tipping over,

and it's able to do this because its legs

are a combination of rigid materials,

which is what we traditionally
use to make robots,

and soft materials.

Jumping is another really interesting way
to get around when you're very small.

So these insects store energy in a spring

and release that really quickly
to get the high power they need

to jump out of water, for example.

So one of the big
contributions from my lab

has been to combine
rigid and soft materials

in very, very small mechanisms.

So this jumping mechanism
is about 4 millimeters on a side,

so really tiny.

The hard material here is silicon,
and the soft material is silicone rubber.

And the basic idea is that
we're going to compress this,

store energy in the springs,
and then release it to jump.

So there's no motors
on board this right now, no power.

This is actuated with a method
that we call in my lab

"graduate student with tweezers."

So what you'll see in the next video

is this guy doing
amazingly well for its jumps.

So this is Aaron, the graduate student
in question, with the tweezers,

and what you see is
this 4-millimeter-sized mechanism

jumping almost 40 centimeters high.

That's almost a hundred times
its own length. Right?

And it survives, bounces on the table,

it's incredibly robust, and of course
survives quite well until we lose it

because it's very tiny.

Ultimately, though, we want
to add motors to this too,

and we have students in the lab
working on millimeter-sized motors

to eventually integrate onto
small, autonomous robots.

But in order to look at mobility and
locomotion at this size scale to start,

we're cheating and using magnets.

So this shows what would eventually
be part of a micro robot leg,

and you can see the silicone rubber joints

and there's an embedded magnet
that's being moved around

by an external magnetic field.

So this leads to the robot
that I showed you earlier.

The really interesting thing
that this robot can help us figure out

is how insects move at this scale.

We have a really good model
for how everything

from a cockroach up to an elephant moves.

We all move in this kind of bouncy way

when we run.

But when I'm really small, my feet,

the forces between my feet and the ground,

are going to affect my locomotion
a lot more than my mass,

which is what causes that bouncy motion.

So this guy doesn't work quite yet,

but we do have slightly larger versions

that do run around.

So this is about a centimeter cube,

a centimeter on a side, so very tiny,

and we've gotten this to run
about 10 body lengths per second,

so 10 centimeters per second.

It's pretty quick for a little, small guy,

and that's really only limited by our test setup.

This gives you some idea
of how it works right now.

We can also make 3D-printed
versions of this

that can climb over obstacles

a lot like the cockroach
that you saw earlier.

But ultimately we want to add
everything onboard the robot. Right?

We want sensing, power, control,
actuation all together,

and not everything
needs to be bio-inspired.

So this robot's about the size
of a tic-tac, right?

And in this case, instead of magnets
or muscles to move this around,

we use rockets.

So this is a micro-fabricated
energetic material,

and we can create tiny pixels of this,

and we can put one of these pixels

on the belly of this robot,

and this robot, then, is going to jump

when it senses an increase in light.

So the next video is one of my favorites.

So you have this 300 milligram robot

jumping about eight centimeters
in the air. Right?

It's only four by four
by seven millimeters in size.

And you'll see a big flash
at the beginning

when the energetic is set off,

and the robot tumbling through the air.

So there was that big flash,

and you can see the robot
jumping up through the air.

So there's no tethers on this,
no wires connecting to this.

Everything is onboard,
and it jumped in response

to the student just flicking on
a desk lamp next to it.

So I think you can imagine
all the kind of cool things

that we could do with robots

that can run and crawl
and jump and role at this size scale.

Right? Imagine the rubble that you get

after a natural disaster
like an earthquake.

Imagine these small robots
running through that rubble

to look for survivors.

Or imagine a lot of small robots

running around a bridge

in order to inspect it
and make sure it's safe

so you don't get collapses
like this that happened

outside of Minneapolis in 2007.

Or just imagine what you could do

if you had robots that could
swim through your blood.

Right? "Fantastic Voyage," Isaac Asimov.

Or they could operate without having
to cut you open in the first place.

Or we could radically change
the way we build things

if we have our tiny robots

work the same way that termites do.

And they build these incredible
eight-meter-high mounds,

effectively well-ventilated
apartment buildings for other termites

in Africa and Australia.

So I think I've given you
some of the possibilities

of what we can do with these small robots,

and hopefully we've made
some advances so far,

but there's still a long way to go,

and hopefully some of you
can contribute to that destination.

Thanks very much.

(Applause)