All language subtitles for 06_component-selection.en

Next, I wanna take a look at
the components that constitute a robot and

then try to analyze the effects of these
components on the agility of the robot.

And more precisely, we'll be looking
at the stopping distance of the robot.

So, this chart illustrates some of the
design choices you might have if you go

online.

So I've chosen to visit dji.com and

pull off some frames that
you can buy off the shelf.

DJI is currently the largest
manufacturer of drones and

they have a wide selection of frames,
batteries, propellers and motors.

In addition to that,
you need an autopilot.

Pixhawk is one that's open source and
sold by 3D Robotics.

You can also buy high level processors
such as those made by Intel.

You clearly need the autopilot for doing
low level control and you need something

like the Intel processor you see
here to do high level computations.

You want to pay particular attention
to the weight of each of these

because eventually your robot will
have to carry these as it flies.

So the control architecture,
you might think about,

involves using this low level processor to
drive the motors and the propellers and

a high level processor like
the Intel which communicates with

a lower level processor and commands a low
level processor to drive the vehicle.

In addition you also
want to have something

that complements the autonomous system.

A radio controller in case you have
to take control of the vehicle.

So we show standard components here
that you can buy off the shelf.

This is an example of an outdoor
platform that we built.

And in this video you will essentially see
that we have taken standard off the shelf

components, a DJI platform with motors
that you can buy from the DJI website

with a simulated payload,
it's a 600 gram payload and aluminum block

that simulates all the payload we
might want to carry in the future.

It also has on board a 721 gram battery.

So this platform has a thrust to weight
ratio which is greater than 2.7 and

this is important.

If you maximize the trust to weight ratio,

you essentially maximize
the acceleration as we've seen before.

In addition to the processors,
you also have to carry sensors.

Here we show two sets of sensors that
we commonly use in our laboratory:

A laser scanner, and
the laser scanner weighs about 270 grams.

A camera system that
weighs about 80 grams.

And you also wanna think
about power consumption and

there are two sources
of power consumption.

First, the device itself consumes power.

It's roughly 10 watts for a laser scanner
and 1.5 watts for the scanner system.

But in edition you're
carrying these two payloads.

The fact that you're carrying a 270
gram laser scanner means you're burning

roughly 50 to 60 watts of power.

LIkewise the fact you're carrying
an 80 gram camera means you're burning

roughly 15 watts of power.

So you wanna think about how heavy
a sensor is, You also wanna see its range.

And all of those play into how fast
the vehicle actually can go because

longer the range,
longer the stopping distance can be.

You can detect obstacles far away, and
therefore you have more time to come

to a stop if you see
an obstacle in front of you.

This in turn allows you
to go at a higher speed.

Of course, longer the range,
the heavier your sensor might be, and

that in turn increases
the weight of the platform.

While it increases
the weight of the platform,

it'll decrease your trust to rate ratio.

So this in an interesting
design space to explore.

So here are some examples of
platforms we've built and

tested in our laboratory in the last year.

All these platforms are autonomous,
they're different sizes,

they carry different sensors.

They weigh different amounts and
they consume different amounts of power.