Naked Science Forum
Non Life Sciences => Technology => Topic started by: Karsten on 29/08/2009 17:07:02
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Can't help but share this video. I guess I did not pay attention to what was going on in this area of technology for a while. Last time I looked (30 years ago) you just flew around with a radio controlled helicopter. And most of the time they did not even get of the ground. Times have changed I guess. We are getting closer to the flight capabilities of insects.
Is this done all by direct hand-control via the transmitter or are we talking about pre-programmed maneuvers saved in the transmitter?
Your thoughts?
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Fake.
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Fake.
That is what I thought at first. But then there is this:
and this:
and this:
and this:
and so forth...
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There are points in that vid where the heli seems to be hovering, or moving very slowly while orientated vertically. It also flies linear courses upside down but but shows no sign of the rotor either reversing direction or reversing pitch, neither of which is a trivial thing to do in flight.
At a few other points in the vid it's clear that it's being swung about a pivot i.e. it's not just moving from side to side but following an arc, just as though it was on the end of a stick, and at other points it's pretty clear that it's on a wire. Some of the maneuvers it does would require more energy than could be supplied in a model heli of that size and in others the rotor would almost certainly crash into the tailboom.
RC Helis are notoriously difficult to control and even maintaining a basic stable hover is quite an achievement; I simply can't believe that those maneuvers were controlled so precisely by a human, using just their hands and a simple RC control unit.
Some of the not-impossible maneuvers could be done by an FCS (Flight Control System) but I've a bit of experience in writing FCS software (for simulators only) and just doing the basic stuff, like maintaining altitude and heading isn't exactly trivial. And even then, this basic stuff requires the FCS to be carefully tuned to match the aircraft. Even the military FCSs found in the latest generations of fly-by-wire fighters couldn't perform those maneuvers at those speeds. In short, the heli is too small to carry an on-board FCS capable of those maneuvers and even if it were using a ground based FCS, running on a high-power workstation, it would still need more processing power than it could carry to gather the data from the many sensors it would have to be fitted with, beam it wirelessly down to the ground station and then act upon the control inputs it receives in response. I'll not go into the bandwidth required for the comms link, and nor the fact that to operate at those speeds, the protocol would have to be not only very low-cpu intensive but also bulletproof.
I really don't like saying something is impossible, but the only way I'm going to believe that is if I see it with my own eyes.
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I simply can't believe that those maneuvers were controlled so precisely by a human, using just their hands and a simple RC control unit.
(...)
I really don't like saying something is impossible, but the only way I'm going to believe that is if I see it with my own eyes.
I have to say that I felt the same way. However, after seeing video clip after video clip of RC helicopters doing those things, looking at footage of two championship and several competitors, seeing the pilot of the first clip I posted (Alan Szabo) as a participant in a video of the championships in 2009, seeing several clips where helicopters crash, one clip that shows the remote control filmed in sync with the flight of the helicopter, etc, etc. I am coming to the opinion that this must be something that is possible even if I did not see it with my own eyes. What would be the motive for so many individuals and promoters of the hobby to fake video after video? Most have no commercial interest. A lot are just some people posting what they filmed somewhere. The people filmed have a reputation to loose and are not just somebody. Unlike those videos that turn out to be a fake, there are very few comments on YouTube that claim that the videos are fake and explain how it was done. What you see in the first clip I posted (and in the ones I posted later) seems to be the real deal.
Just do a search on "3D RC helicopters" or go to YouTube and search the same term or "3D Masters". It is all over the place. I cannot justify being a skeptic any longer. There is too much of the same out there and way too little criticism posted.
So, how is it done? I read they use gyro(s). The transmitters are programmable. I guess all this helps somewhat. But how do you do it? Do you fly the maneuver and record the input you gave into the transmitter, save the piece and play it when necessary? Or is it truly just hand control?
This is the video that shows the RC control at the same time. Do servos respond this fast these days?
Mind boggling.