All language subtitles for 01_unmanned-aerial-vehicles.en

Welcome to Aerial Robotics, the first
course in the Robotics Specialization.

This course exposes you to the mechanics,
design, the control and planning

of robotic flight in three-dimensional
environments for micro aerial vehicles.

With an emphasis on quadrotors,
a special, but

important class of micro aerial vehicles.

You will learn about the opportunities in
the field of aerial robotics or drones.

You will get a basic understanding of
the dynamics of micro aerial vehicles and

how to control them.

We will discuss the challenges in
developing sensors for safe and

autonomous flight.

You will learn how to
get robots to plan and

execute complex maneuvers in
three-dimensional environments.

We will discuss the effects of size
on maneuverability and agility.

We use a combination of simple models,
interactive simulations and

illustrative experiments to give
you an understanding of how

robotics technology is
changing the world we live in.

And now, let's begin.

[MUSIC]

Unmanned aerial vehicles are closely
related to aerial robotics.

Over the last 30 years, the number of UAVs
in the world have grown exponentially.

In 2010, there were predictions
of a $10 billion industry.

Most of the applications being in
the military sector, the civilian sector.

And of course, the DIY sector
where there are thousands if not

millions of users developing all kinds of
software and hardware platforms for UAV's.

The FAA that year, predicted over
15,000 civilian drones by 2020.

Let's fast forward to today.

It's now clear that this
industry is even bigger.

There's widespread interest in UAVs.

In fact, there were 15,000 drones
sold in the US alone every month.

It's already a 15 billion dollar industry
projected to grow 25 billion in 2020 and

the applications range from agriculture,
photography, inspection,

construction, border patrols and
producing movies.

There are many other times that we
use to reference aerial robots or

unmanned aerial vehicles.

The military uses remotely piloted
vehicles as a descriptor for

vehicles that are unmanned.

And of course, the layperson and
the press know them as drones.

The military would question
the use of the term drones.

General Norton Schwartz,
the person who actually used drones and

actually popularized the use of drones
within the military is said to have

said that drones mischaracterize
what these things are.

They're not dumb, nor
are they actually unmanned.

They're remotely piloted vehicles and
you can see that in this picture.

There are two UAV operators,
operating a vehicle from an air force

base in New Mexico and this is true for
every remotely piloted vehicle

that the military uses, but
we're not gonna draw the distinction.

For us, UAVs are the same as
remotely piloted vehicles and

that's the same as aerial robots and
that's the same as drones.

This field is rapidly growing.

In fact, it's evolving and we're just in
the beginning of this evolution process.

There's also a lot of
concern about regulation.

People are worried about UAVs,
whether they are safe or not.

People are worried about privacy.

These UAVs usually have cameras and

the cameras take pictures
that can be intrusive.

There's also a question of security,

as adversaries think about how they can
manipulate sensors or control systems and

tap into the inner workings of a UAV to
do things they were not designed to do.

Our interest in this course is
primarily in micro aerial vehicles.

In contrast to the vehicles that you see
on the right-hand side of the screen,

which can weigh a lot, which are very big
and fly high above the Earth's surface.

The ones on the left-hand side
of the screen are much smaller,

they're capable of navigating
in indoor environments and

three-dimensional unstructured settings
and that's what we're gonna focus on here.

There are many different geometries,

many different designs you can choose
to build micro aerial vehicles.

You might consider using
fixed wing vehicles.

These have a disadvantage as you think
of them as operating in confined spaces.

Vehicles like this cannot just
come to a stop in midair.

They cannot hover like helicopters can.

Flapping wing vehicles that are patterned
after insects or birds can,

in fact, stop and hover.

If you look at the humming bird,

it's capable of hovering in place
by just flapping its wings and

people have tried to build vehicles
based on these kinds of geometries.

However, the fluid
mechanics is complicated.

It involves studying vortex
shedding from wings and

unsteady flows and
it's very hard to model these and

invert these models to control these
kinds of vehicles autonomously.

The obvious geometry to consider when you
consider micro aerial vehicles are rotor

crafts and there are many different
type of rotor crafts you might imagine.

Helicopters are the ones that
we're most accustomed to seeing.

Rotor crafts would consist of
two co-axial rotors spinning in

opposite directions are also
a candidate of geometry,

but the simplest geometry
are simple rotor aircrafts.

Quadrotors or hex rotors,
as you see over here.

This has six rotors, all controlled
independently that allow the vehicle

to be controlled in height and
in orientation and in translation.

The vehicle of choice in this
course is going to be a quadrotor.

Again, this vehicle has four rotors
powered by independent motors all

mounted on a fixed frame and
we tried to make these vehicles smaller.

Because by making them smaller,
you also make them safer and

you make them more maneuverable.