
VertiGo – A Wall-Climbing Robot including Ground-Wall Transition - prostoalex
https://www.disneyresearch.com/publication/vertigo/
======
TeMPOraL
A month ago in Shenzhen I've seen better-looking RC cars that can drive up the
walls. They're being sold on the market like any other toy. I really thought
that product has already reached the US, so I'm surprised that a wall-climbing
car is considered something new / original in this article.

EDIT: Chinese cars are similar to [0], only bigger. I thought they were a
relatively new thing, given that I've first seen them suddenly appearing in
late November, but if you believe the upload date of this video, the idea has
been in the field for at least 5 years.

[0] -
[https://www.youtube.com/watch?v=A_nYNuoZteA](https://www.youtube.com/watch?v=A_nYNuoZteA)

~~~
detaro
I think the new thing is that it can drive on the ground and then go up the
wall, and probably can deal with uneven surfaces better. All I've seen before
(and you are right, those haven been around for ages) really have to suck to a
even surface.

~~~
TeMPOraL
I'll grant the uneven surfaces, but transitioning between the ground and the
wall is something those Chinese toys do perfectly fine; I've seen it
demonstrated in a badly maintained pedestrian underpass, so the walls weren't
exactly even there. It passes the test for an urban toy (indoor and outdoor),
though I doubt it would play well with e.g. rocky terrain.

~~~
detaro
Ok, then I have no idea either ;) I only know these tiny ones like in the
video, and they are limited like that.

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johansch
Sudden insight: HN might be the world's best place to find prior art.

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hawski
That's cool, but I am waiting for one practical application: dusting Roomba.

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hanniabu
I love simple innovations like this where it seems like a pretty obvious
evolution in hindsight, yet it so hard to see until somebody makes it. This is
a combination of a quadcopter and RC car, can't wait to see where people take
this.

~~~
mickeypi
[http://www.parrot.com/products/rolling-
spider/](http://www.parrot.com/products/rolling-spider/) Not exactly the same
thing but similar.

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johansch
New battery technologies have enabled them to build a small vehicle that can
deal with both terra firma and that other stuff - air (which so easily can be
mistaken for vacuum, when compared to firm ground)!

Is this the first small vehicle that deals with them both as a system?

~~~
swampthing
I have a toy car I bought 5 years ago from some street vendor in Hong Kong
that can go on land and up walls (it has fans too). It uses regular AA
batteries.

The main innovation here, as far as I can see, is that it can automatically
make the switch between horizontal and vertical.

~~~
johansch
Cool :) "The future is already here — it's just not very evenly distributed."
(William Gibson)

Any photos or keywords to search for online?

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tboughen
What does upper bound on the mass of a vehicle like this depend upon? Target
battery life? Air throughput? Any others?

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iask
I love it! It's an interesting concept to build on. Battery is always a
bummer...weight or run-time.

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tdy721
Disney also built a tiny robot soccer ball that rolled into my heart. What
can't they do!?

~~~
1qaz2wsx3edc
Take stuff out of the vault. /s

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dang
Url changed from [http://www.theverge.com/2015/12/29/10685710/disney-
vertigo-r...](http://www.theverge.com/2015/12/29/10685710/disney-vertigo-
robot-climbs-walls), which points to this.

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ColinWright
_Screw it - I provided an answer, I 'm being accused of being smug. Had
enough. 2016 is my year of no longer contributing to HN._

[https://xkcd.com/386/](https://xkcd.com/386/)

~~~
grondilu
That's not the question I'm asking. Assume perfect adherence on the wall. My
question is : to remain stationary, do the propellers need to exert a force
equal to the weight of the device?

In other words : if this machine can climb up a wall straight up, does that
mean it could also climb up in the air?

~~~
FabHK
> if this machine can climb up a wall straight up, does that mean it could
> also climb up in the air?

Interesting question! I think the answer is "not necessarily", particularly if
the coefficient of friction of the wheels is pretty high.

Think of it this way: the weight of the machine points down. This down force
needs to be compensated by an upward force, otherwise we'd have acceleration
downwards. This necessary upward force can consist of two components: The
upward component of the thrust generated by the propellers, and the friction.
Now, the force exerted by friction is the normal force (i.e. perpendicular
against the wall) times the coefficient of friction, call it c_f. If I
remember correctly, for (macroscopic) things, that coefficient of friction is
less than one (i.e., a car cannot decelerate with a 1 g or more, unless
there's a spoiler that pushes the car onto the road, thus increasing the
normal force to something larger than the weight of the car). Now, the normal
force is the component of thrust perpendicular to the wall. (See ASCII "art"
below).

Now, suppose the coefficient of friction is very close to one, and thrust is
angled 45 degrees down away from the wall. Then:

weight = 1g (down)

upward thrust = 1/2 g + a bit (up)

normal force = 1/2 g + a bit (towards wall)

friction = (1/2 g + a bit) * c_f (up)

total upwards force = Upward force + friction = 1g (up)

Now the system is in equilibrium, and the total thrust is sqrt(2) * (1/2 g + a
bit) = 0.75 g, say.

Thus, my hunch is that the thing can go up the wall even if it can't fly by
itself, if the friction is big enough.

| weight

| |

| |

| |

| |

| V

|O\

| X <\-- Normal = horizontal component of thrust

|O/

| ^ |\

| | . \

| | . . \

| | Thrust

| |

| upward component of thrust + friction

Dammit! Hard to do ASCII art here :-)

~~~
rtkwe
According to the paper the wheels are unpowered so wouldn't there only be the
rolling friction of the wheel's bearings between the car and the wall? It'd be
some but very little.

> The wheels are mounted with a double wishbone suspension based on model-car
> oil dampers, but they are not propelled in any way.

~~~
FabHK
> According to the paper the wheels are unpowered so wouldn't there only be
> the rolling friction of the wheel's bearings between the car and the wall?
> It'd be some but very little.

You're right. I've assumed that it drives horizontally along the wall. As it
climbs up the wall, you're absolutely right - the thrust has to overcome the
weight AND provide at least a bit of a normal force to keep it pressed to the
wall.

Given that the video clearly shows it driving up the wall, this particular
vehicle must indeed be able to develop enough thrust to overcome its own
weight.

