Slashdot Mirror
Quadrocopters Throwing and Catching an Inverted Pendulum
derGoldstein writes "We've seen some very impressive aerobatics performed by quadrocopters before, but this is getting ridiculous. Robohub points to the latest advancement from the Flying Machine Arena, which developed algorithms that allow quadrocopters to juggle an inverted pendulum. One of the researchers working on it said, 'We started off with some back-of-the-envelope calculations, wondering whether it would even be physically possible to throw and catch a pendulum. This told us that achieving this maneuver would really push the dynamic capabilities of the system. As it turned out, it is probably the most challenging task we've had our quadrocopters do. With significantly less than one second to measure the pendulum flight and get the catching vehicle in place, it's the combination of mathematical models with real-time trajectory generation, optimal control, and learning from previous iterations that allowed us to implement this.'"
It don't mean a thing if they don't compute that swing.
rewriting history since 2109
Science. Making ideas possible.
It is now clearly obvious: in the future, the weapon of choice to fight robots will be an aluminium baseball bat.
Get free satoshi (Bitcoin) and Dogecoins
A new way to throw a grenade through a tiny window on the 6th floor on the cheap.
...why do they have to call it an inverted pendulum instead of a stick?
systemd is Roko's Basilisk.
This is great, now American will be able to kill arab civilians in a fancy way
What, by using a Kraut stick grenade as the inverted pendulum in question?
Ezekiel 23:20
I'm impressed.
Because an inverted pendulum is a class and a stick is a particular instance (as it would be a drunkard).
Questions raise, answers kill. Raise questions to stay alive.
It would have been funny to end the video with regular movie-style scrolling credits and have "42 quadrocopters have been harmed in the making of this film."
Get free satoshi (Bitcoin) and Dogecoins
It's about sounding "science", as much as it a well defined scientific concept. An inverted pendulum is a well defined controls problem, where you take an unstable system and make it stable with your control laws. This is often solved in one dimension as part of undergraduate controls classwork with a cart and a stick balanced above it. The description of throwing and catching inverted pendulums perfectly describes what they are doing.
On the other hand, if they said they were throwing and catching a stick, I'd assume they were simply catching it. The balancing the unstable system with their control laws would not be assumed. Hope this helps.
Is it just me or have you just misspeled "secession"?
Ezekiel 23:20
I was so outraged by the thought of drones used against me and not against some foreigner that my trembling rage filled fingers hit the wrong keys.
You must gather your party before venturing forth.
This looks like it was achieved using motion capture equipment, as seen by the usage of retro-reflective balls (see them shine at 1:44). If that's the case, it would imply that the computing was done remotely. Motion capture gear typically works at 120 frames per second, which would give the system enough time resolution to figure this out on the fly with a decent PC on the back-end.
It'll be a while before the quadrucopters can do this in their own but the program figuring out the catching move is impressive nonetheless.
Nothing is enough for whom enough is too little - Confucius
Can it be done with a tricopter? Or a bicopter with propellers that pivot?
At one point in the film there is a cloud of ???. Is this the staff being ground up due to an apparent miss?
The end of the staff has a small balloon on it, filled with powder -- see explanation further down the linked page. Sounds like a small hacky-sack with a rubber (grippy) surface. They call this a "damper" and one popped open.
Adding my compliments to the rest -- very cool demonstration of control theory.
That is pretty impressive but it also serves to reinforce the fact that without the über power source, it's just a nifty demo. This is what I keep hearing from SWAT teams who either spend a ton of money (e.g. > $25k) buying one or are looking at getting one and then they discover that they can't put a camera up in the air for hours at a time without landing to change batteries.
And did anyone else read "Pole Acrobatics" and have a totally different expectation? ;-)
Typing "inverted pendulum" into google would have saved you some embarrassment
Not from not knowing what an inverted pendulum is, there's no shame in that.
The shame is from:
a) Not knowing how to use google
b) Trying to sound smarter than people who can do the math needed to toss inverted pendulums between quadcopters (which they designed and built).
No sig today...
... I imagine stupid people tricks will remain more popular than smart robot ones.
Is the actual balancing performed based solely on the forces applied to the sending/receiving actors? How necessary are the data markers on the stick? I'm wondering that if the two actors knew where each other were in space, and based on the balancing the sending actor has to perform couldn't the receiving actor make a guess where it needs to be in any case? Could I (as an actor in this scenario) make an educated guess as to the length of the stick based on the corrections I have to perform in order to keep it upright? Of course I may be asking questions that can't be answered because we don't have the full picture from the demonstration.
Wake me up when they can do that with inverted compound pendulums.
Cirque du Soleil will probably put robots in the show when they can do that.
Or maybe an Aibo balancing on a big dog balancing on a CAM. (Bonus if they can all "sing")
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
A puff of smoke at 1:33; I think someone lost a bit of propeller to the pendulum.
And I still can't even get my quadcopter for a normal spin without crashing it into the nearest wall or tree!
How the heck can I get mine to hover at least somewhat in one place? I know these use the cameras for real precise tracking, but mine is the exact opposite it seems. Grrrr
Amusement park rides of the future are going to be awesome!
That link points out that a human is also an instance of an inverted pendulum. I think I see some real potential for this now.
As amazing as this is (and it IS friggin' amazing), remember that the human brain does this throw, catch, reposition, recalculate, and respond stuff effortlessly. Just play catch with a ball and your 5 year old child. Animals with pea-sized brains do it great, too! -- Josh
To be pedantic, "Succession" would be viable as a result of impeachment. Just saying.
Always going forward, 'cause we can't find reverse.
Very good. Now let's do it with flaming chainsaws.
The Official Site of 1337 Pwnage
Yeah, troll, because quadcopters' only use is to develop military tech. Must have never heard of people studying control engineering. Ultimately, proof is in the pudding. Either you make a device that works using your control scheme, or it doesn't. Now fuck off.
A successful API design takes a mixture of software design and pedagogy.
The quadcopters are very basic, sensor-wise. They may have an inertial measurement unit onboard, or may not, I don't know. They probably know their battery state, and maybe motor current. A reverse channel from a quadcopter adds extra weight, I'd avoid it if I could. Other than that, everything is sensed by a standard motion capture (mocap) system that illuminates the scene with infrared light and tracks the reflective marker balls on the quadcopters and the pendulum.
They put small balloons filled with flour as dampers at the end of the pendulum. This is simply to provide something that will dissipate remaining kinetic energy when the stick hits the quadcopter -- there's always some velocity mismatch. If it was a bare stick, there wouldn't be enough friction to keep it on the quadcopter, and it would bounce away right after touching the quadcopter during a capture. Remember that our finger skin is pretty special when a bit moist -- it grips random things extremely well. When you have a carbon fiber stick and a plastic platform, it's a different story.
A successful API design takes a mixture of software design and pedagogy.