A robot that runs and swims like a salamander

This is Pleurobot.

Pleurobot is a robot that we designed
to closely mimic a salamander species

called ??

Pleurobot can walk, as you can see here,

and as you'll see later, it can also swim.

So you might ask,
why did we design this robot?

And in fact, this robot has been designed
as a scientific tool for neuroscience.

Indeed, we designed it
together with neurobiologists

to understand how animals move,

and especially how the spinal cord
controls locomotion.

But the more I work in biorobotics,

the more I'm really impressed
by animal locomotion.

If you think of a dolphin swimming
or a cat running or jumping around,

or even us as humans,

when you go jogging or play tennis,

we do amazing things.

And in fact, our nervous system solves
a very, very complex control problem.

It has to coordinate more
or less 200 muscles perfectly,

because if the coordination is bad,
we fall over or we do bad locomotion.

And my goal is to understand
how this works.

There are four main components
behind animal locomotion.

The first component is just the body,

and in fact we should never underestimate
what extent the biomechanics

already simplify locomotion in animals.

Then you have the spinal cord,

and in the spinal cord you find reflexes,

like multiple reflexes that create
a sensory motor coordination loop

between neural activity in the spinal cord
and mechanical activity.

A third component
are central pattern generators.

These are very interesting circuits
in the spinal cord of vertebrate animals

that can generate, by themselves, very
coordinated rhythmic patterns of activity

while receiving only
very simple input signals.

And these input signals come from
descending modulation

from higher parts of the brain,
from the motor cortex, the cerebellum,

the basal ganglia, will all modulate
activity of the spinal cord

while we do locomotion.

But what's interesting is to what extent
just a low level component,

the spinal cord, together with the body,
already solves a big part

of the locomotion problem,

and you probably know it by the fact
that you can cut the head of the chicken,

it can still run for a while,

showing that just the lower part,
spinal cord and body,

already solves a big part of locomotion.

Now, understanding how this works
is very complex,

because first of all,

recording activity in the spinal cord
is very difficult.

It's much easier to implant electrodes
in the motor cortex

than in the spinal cord, because
it's protected by the vertebrae.

Especially in humans,
it's very hard to do.

A second difficulty is that locomotion
is really due to a very complex

and very dynamic interaction
between these four components.

So it's very hard to find out
what's the role of each over time.

This is where biorobots like Pleurobot
and mathematical models

can really help.

So what's biorobotics?

Biorobotics is a very active field
of research in robotics

where people want to take inspiration
from animals to make robots

to go outdoors,

like service robots
or search-and-rescue robots

or field robots,

and the big goal here is
to take inspiration from animals

to make robotics that can handle
complex terrain --

stairs, mountains, forests,

places where robots
still have difficulties

and where animals can do
a much better job.

The robot can be
a wonderful scientific tool as well.

There are some very nice projects
where robots are used

like a scientific tool for neuroscience,
for biomechanics, or for ?? dynamics.

And this is exactly
the purpose of Pleurobot.

So what we do in my lab
is to collaborate with neurobiologists

like Jean-Marie Cabelguen,
a neurobiologist in Bordeaux in France,

and we want to make spinal cord models
and validate them on robots.

And here we want to start simple.

So it's good to start with simple animals

like lampreys, which are
very primitive fish,

and then gradually go toward
more complex locomotion,

like in salamanders,

but also in cats and in humans,

in mammals.

And here, a robot becomes
an interesting tool

to validate our models,

and in fact, for me, Pleurobot
is a kind of dream becoming true.

Like, more or less 20 years ago
I was already working on a computer

making simulations of lamprey
and salamander locomotion

during my Ph.D