VertiGo – A Wall-Climbing Robot including Ground-Wall Transition | Hacker News Reader

VertiGo – A Wall-Climbing Robot including Ground-Wall Transition

disneyresearch.com

89 pointsprostoalex31 comments

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

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.

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.

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

I have played with wall climbing cars some years back in italy. I believe they had been bought from thinkgeek.

But they were suction-based and had to be manually positioned on the surface.

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

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

Deleted comment

Watching the video, there are at least two motors, driving each front wheel, so yes, with appropriate gearing, it looks capable to climb vertically against gravity.

Also, it looks like the fans are used to blow/push ( http://physics.stackexchange.com/questions/135016/what-is-go... ) the vehicle onto the wall, and angled so there will be a portion of force developed in the direction of travel.

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

From the paper on the Disney Research site. [0]

[0] https://www.disneyresearch.com/publication/vertigo/

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.

http://www.parrot.com/products/rolling-spider/ Not exactly the same thing but similar.

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?

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.

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

Any photos or keywords to search for online?

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

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

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

Take stuff out of the vault. /s

Url changed from http://www.theverge.com/2015/12/29/10685710/disney-vertigo-r..., which points to this.

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/

We detached this subthread from https://news.ycombinator.com/item?id=10826643 and marked it off-topic.

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?

Not necessarily. The weight of the vehicle is offset by the friction of the wheels on the wall.

Imagine an ant. It doesn't have an external force such as a propeller. It can climb up walls but it can't fly in any capacity.

> 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 :-)

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.

> 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.