The new bionics that let us run, climb and dance

Hugh Herr is building the next generation of bionic limbs, robotic prosthetics inspired by nature's own designs. Herr lost both legs in a climbing accident 30 years ago; now, as the head of the MIT Media Lab’s Biomechatronics group, he shows his incredible technology in a talk that's both technical and deeply personal — with the help of ballroom dancer Adrianne Haslet-Davis, who lost her left leg in the 2013 Boston Marathon bombing, and performs again for the first time on the TED stage.

Looking deeply inside nature

through the magnifying glass of science,

designers extract principles,

processes and materials

that are forming the very
basis of design methodology,

from synthetic constructs that resemble

biological materials

to computational methods that
emulate neural processes,

nature is driving design.

Design is also driving nature.

In realms of genetics, regenerative medicine

and synthetic biology,

designers are growing novel technologies

not foreseen or anticipated by nature.

Bionics explores the interplay

between biology and design.

As you can see, my legs are bionic.

Today I will tell human stories

of bionic integration,

how electromechanics attached to the body

and implanted inside the body

are beginning to bridge the gap

between disability and ability,

between human limitation

and human potential.

Bionics has defined my physicality.

In 1982, both of my legs were amputated

due to tissue damage from frostbite

incurred during a mountain climbing accident.

At that time, I didn't view my body

as broken.

I reasoned that a human being

can never be broken.

Technology is broken.

Technology is inadequate.

This simple but powerful idea

was a call to arms

to advance technology

for the elimination of my own disability

and ultimately the disability of others.

I began by developing specialized limbs

that allowed me to return

to the vertical world of rock and ice climbing.

I quickly realized that the artificial part of my body

is malleable,

able to take on any form, any function,

a blank slate through which to create

perhaps structures that could extend beyond

biological capability.

I made my height adjustable.

I could be as short as five feet or as tall as I'd like.

(Laughter)

So when I was feeling badly about myself,

insecure, I would jack my height up,

but when I was feeling confident and suave,

I would knock my height down a notch

just to give the competition a chance.

(Laughter) (Applause)

Narrow, wedged feet allowed me to climb

steep rock fissures

where the human foot cannot penetrate,

and spiked feet enabled me to climb

vertical ice walls

without ever experiencing muscle leg fatigue.

Through technological innovation,

I returned to my sport stronger and better.

Technology had eliminated my disability

and allowed me a new climbing prowess.

As a young man, I imagined a future world

where technology so advanced

could rid the world of disability,

a world in which neural implants would allow

the visually impaired to see,

a world in which the paralyzed could walk

via body exoskeletons.

Sadly, because of deficiencies in technology,

disability is rampant in the world.

This gentleman is missing three limbs.

As a testimony to current technology,

he is out of the wheelchair,

but we need to do a better job in bionics

to allow one day full rehabilitation

for a person with this level of injury.

At the MIT Media Lab, we've established

the Center for Extreme Bionics.

The mission of the center

is to put forth fundamental science

and technological capability that will allow

the biomechatronic and regenerative repair of humans

across a broad range

of brain and body disabilities.

Today, I'm going to tell you how my legs function,

how they work,

as a case in point for this center.

Now, I made sure to shave my legs last night,

because I knew I'd be showing them off.

Bionics entails the engineering
of extreme interfaces.

There's three extreme interfaces in my bionic limbs:

mechanical, how my limbs are attached

to my biological body;

dynamic, how they move like flesh and bone;

and electrical, how they communicate

with my nervous system.

I'll begin with mechanical interface.

In the area of design, we still do not understand

how to attach devices to the body mechanically.

It's extraordinary to me that in this day and age,

one of the most mature, oldest technologies

in the human timeline, the shoe,

still gives us blisters.

How can this be?

We have no idea how to attach things to our bodies.

This is the beautifully lyrical design work

of Professor Neri Oxman at the MIT Media Lab,

showing spatially varying exoskeletal impedances,

shown here by color variation

in this 3D-printed model.

Imagine a future where clothing

is stiff and soft where you need it,

when you need it, for optimal support and flexibility,

without ever causing discomfort.

My bionic limbs are attached to my biological body

via synthetic skins

with stiffness variations

that mirror my underlying tissue biomechanics.

To achieve that mirroring,

we first developed a mathematical model

of my biological limb.

To that end, we used imaging tools such as MRI

to look inside my body

to figure out the geometries and locations

of various tissues.

We also took robotic tools.

Here's a 14-actuator circle

that goes around the biological limb.

The actuators come in, find the surface of the limb,

measure its unloaded shape,

and then they push on the tissues

to measure tissue compliances

at each anatomical point.

We combine these imaging and robotic data

to build a mathematical description

of my biological limb, shown on the left.

You see a bunch of points, or nodes.

At each node, there's a color that
represents tissue compliance.

We then do a mathematical transformation

to the design of the synthetic skin

shown on the right,

and we've discovered optimality is

where the body is stiff, the
synthetic skin should be soft,

where the body is soft,
the synthetic skin is stiff,

and this mirroring occurs

across all tissue compliances.

With this framework,

we produced bionic limbs

that are the most comfortable limbs I've ever worn.

Clearly in the future,

our clothing, our shoes, our braces,

our prostheses, will no longer be designed

and manufactured using artisan strategies,

but rather data-driven quantitative frameworks.

In that future, our shoes

will no longer give us blisters.

We're also embedding sensing and smart materials

into the synthetic skins.

This is a material

developed by SRI International, California.

Under electrostatic effect, it changes stiffness.

So under zero voltage, the material is compliant.

It's floppy like paper.

Then the button's pushed, a voltage is applied,

and it becomes stiff as a board.

We embed this material into the synthetic skin

that attaches my bionic limb to my biological body.

When I walk here,

it's no voltage.

My interface is soft and compliant.

The button's pushed, voltage is applied,

and it stiffens,

offering me a greater maneuverability

of the bionic limb.

We're also building exoskeletons.

This exoskeleton becomes stiff and soft

in just the right areas of the running cycle

to protect the biological joints

from high impacts and degradation.

In the future, we'll all be wearing exoskeletons

in common activities such as running.

Next, dynamic interface.

How do my bionic limbs move like flesh and bone?

At my MIT lab, we study how humans

with normal physiologies stand, walk and run.

What are the muscles doing,

and how are they controlled by the spinal cord?

This basic science motivates what we build.

We're building bionic ankles, knees and hips.

We're building body parts from the ground up.

The bionic limbs that I'm wearing are called BiOMs.

They've been fitted to nearly 1,000 patients,

400 of which have been U.S. wounded soldiers.

How does it work? At heel
strike, under computer control,

the system controls stiffness

to attenuate the shock of the limb hitting the ground.

Then at mid-stance, the bionic limb outputs

high torques and powers to lift the person

into the walking stride,

comparable to how muscles work in the calf region.

This bionic propulsion is very important

clinically to patients.

So, on the left you see the bionic device

worn by a lady --

on the right a passive device worn by the same lady

that fails to emulate normal muscle function --

enabling her to do something

everyone should be able to do,

go up and down their steps at home.

Bionics also allows for extraordinary athletic feats.

Here's a gentleman running up a rocky pathway.

This is Steve Martin, not the comedian,

who lost his legs in a bomb blast in Afghanistan.

We're also building exoskeletal structures

using these same principles

that wrap around a biological limb.

This gentleman does not have

any leg condition, any disability.

He has a normal physiology,

so these exoskeletons are applying

muscle-like torques and powers

so that his own muscles need not apply

those torques and powers.

This is the first exoskeleton in history

that actually augments human walking.

It significantly reduces metabolic cost.

It's so profound in its augmentation

that when a normal, healthy person

wears the device for 40 minutes

and then takes it off,

their own biological legs

feel ridiculously heavy and awkward.

We're beginning the age in which

machines attached to our bodies

will make us stronger and faster

and more efficient.

Moving on to electrical interface,

how do my bionic limbs communicate

with my nervous system?

Across my residual limb are electrodes

that measure the electrical pulse of my muscles.

That's communicated to the bionic limb,

so when I think about moving my phantom limb,

the robot tracks those movement desires.

This diagram shows fundamentally

how the bionic limb is controlled,

so we model the missing biological limb,

and we've discovered what reflexes occurred,

how the reflexes of the spinal cord

are controlling the muscles,

and that capability is embedded

in the chips of the bionic limb.

What we've done, then, is we modulate

the sensitivity of the reflex,

the modeled spinal reflex,

with the neural signal,

so when I relax my muscles in my residual limb,

I get very little torque and power,

but the more I fire my muscles,

the more torque I get,

and I can even run.

And that was the first demonstration

of a running gait under neural command.

Feels great.

(Applause)

We want to go a step further.

We want to actually close the loop

between the human and the bionic external limb.

We're doing experiments where we're growing

nerves, transected nerves,

through channels, or micro-channel rays.

On the other side of the channel,

the nerve then attaches to cells,

skin cells and muscle cells.

In the motor channels we can sense

how the person wishes to move.

That can be sent out wirelessly to the bionic limb,

then sensors on the bionic limb

can be converted to stimulations

in adjacent channels, sensory channels.

So, when this is fully developed

and for human use,

persons like myself will not only have

synthetic limbs that move like flesh and bone,

but actually feel like flesh and bone.

This video shows Lisa Mallette

shortly after being fitted with two bionic limbs.

Indeed, bionics is making

a profound difference in people's lives.

(Video) Lisa Mallette: Oh my God.

Oh my God, I can't believe it.

It's just like I've got a real leg.

Now, don't start running.

Man: Now turn around,

and do the same thing walking up.

Walk up, get on your heel to toe,

like you would normally just walk on level ground.

Try to walk right up the hill.

LM: Oh my God.

Man: Is it pushing you up?

LM: Yes! I'm not even -- I can't even describe it.

Man: It's pushing you right up.

Hugh Herr: Next week, I'm visiting the center's —

(Applause) Thank you, thank you.

Thank you. Next week I'm visiting

the Center for Medicare and Medicaid Services,

and I'm going to try to convince CMS

to grant appropriate code language and pricing

so this technology can be made available

to the patients that need it.

Thank you. (Applause)

It's not well appreciated, but over half

of the world's population

suffers from some form of cognitive,

emotional, sensory or motor condition,

and because of poor technology,

too often, conditions result in disability

and a poorer quality of life.

Basic levels of physiological function

should be a part of our human rights.

Every person should have the right

to live life without disability

if they so choose --

the right to live life without severe depression;

the right to see a loved one

in the case of seeing impaired;

or the right to walk or to dance,

in the case of limb paralysis

or limb amputation.

As a society, we can achieve these human rights

if we accept the proposition

that humans are not disabled.

A person can never be broken.

Our built environment, our technologies,

are broken and disabled.

We the people need not accept our limitations,

but can transcend disability

through technological innovation.

Indeed, through fundamental advances

in bionics in this century,

we will set the technological foundation

for an enhanced human experience,

and we will end disability.

I'd like to finish up with one more story,

a beautiful story,

the story of Adrianne Haslet-Davis.

Adrianne lost her left leg

in the Boston terrorist attack.

I met Adrianne when this photo was taken

at Spaulding Rehabilitation Hospital.

Adrianne is a dancer, a ballroom dancer.

Adrianne breathes and lives dance.

It is her expression. It is her art form.

Naturally, when she lost her limb

in the Boston terrorist attack,

she wanted to return to the dance floor.

After meeting her and driving home in my car,

I thought, I'm an MIT professor.

I have resources. Let's build her a bionic limb

to enable her to go back to her life of dance.

I brought in MIT scientists with expertise

in prosthetics, robotics, machine learning

and biomechanics,

and over a 200-day research period,

we studied dance.

We brought in dancers with biological limbs,

and we studied how do they move,

what forces do they apply on the dance floor,

and we took those data

and we put forth fundamental principles of dance,

reflexive dance capability,

and we embedded that intelligence

into the bionic limb.

Bionics is not only about making people

stronger and faster.

Our expression, our humanity

can be embedded into electromechanics.

It was 3.5 seconds

between the bomb blasts

in the Boston terrorist attack.

In 3.5 seconds, the criminals and cowards

took Adrianne off the dance floor.

In 200 days, we put her back.

We will not be intimidated, brought down,

diminished, conquered or stopped

by acts of violence.

(Applause)

Ladies and gentlemen, please allow me to introduce

Adrianne Haslet-Davis,

her first performance since the attack.

She's dancing with Christian Lightner.

(Applause)

(Music: "Ring My Bell" performed by Enrique Iglesias)

(Applause)

Ladies and gentlemen,

members of the research team,

Elliott Rouse and Nathan Villagaray-Carski.

Elliott and Nathan.

(Applause)