
DARPA helicopter can feel for the ground below to ensure a safe landing - bane
http://www.alphr.com/technology/1001524/darpa-is-building-the-helicopter-of-the-future
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jamesrom
Wow. In hindsight, this idea seems so obvious and incredibly useful. I can't
believe we haven't seen anything like this before.

I would imagine that the ability to land on a hillside would be incredibly
useful for military operations and rescue.

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tenken
> Wow. In hindsight, this idea seems so obvious and incredibly useful. I can't
> believe we haven't seen anything like this before.

Because the track record for "cool ways to land and take off" simply aren't
that great. Eg, see the track record of the Osprey.

[https://en.wikipedia.org/wiki/Bell_Boeing_V-22_Osprey#Contro...](https://en.wikipedia.org/wiki/Bell_Boeing_V-22_Osprey#Controversy)

Another simple point is that current rigid landing skids provide a simple
surface to land with. With "legs" you know have the problem of "landing gear"
which can malfunction, rigid landing skids can hardly malfunction .... oh crap
1 leg is stuck in the "out" position -- how should I land now sir? :)

> I would imagine that the ability to land on a hillside would be incredibly
> useful for military operations and rescue.

Perhaps, but rarely are hill sides flat, nor void of tall obstacles such as
trees. Typically in hot LZ it's in your best interest to not land. By which I
mean being airborne is 1 problem, having landed -- you now have 2 problems
(your static and now need to take-off). This is also true typically in rescue
attempts.

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drzaiusapelord
My understanding is that the Osprey's early issues were mechanical and
training issues and not issues with the concept (propshaft issues, pilots not
trained properly, poorly engineering wiring harnesses, etc) . Those things
were fixed and now the Osprey is used quite a bit. I even saw one fly over my
home the last time Obama visited.

Most of the current and next gen fighters have some level of V/STOL built-in
as well. I think we're pretty far from what you're describing, which was maybe
15-20 years ago. Lets remember that the design team for the Osprey started in
the early 80s and the original prototypes are from the 70s. The Bell XV-15
prototype first flew in '77 and then the larger version as part of this
proposal flew in '83\. Aircraft engineer has gone a long way since. We're able
to do much more today.

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ClintEhrlich
This looks like a very promising research avenue, and I don't mean to
deprecate it in any way. But this part of the article seemed a bit too
pollyannish: "Currently the system hasn’t been tested on a full-scale
helicopter, used instead on a rather large remote- control hobby vehicle. But
as the technology fundamentally works in the same way, there’s no reason to
believe this won’t make its way onto full-sized helicopters in the future."

It's not self evident to me that, at the scales necessary for use in human-
piloted helicopters, the robotic legs would be light enough to avoid causing
thrust-to-weight ratio problems. But as always, I'm rooting for DARPA to make
it work!

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Noctem
Wouldn't it be problematic to takeoff from an uneven surface? It seems like it
would generate more lift from the side with higher ground and end up taking
off diagonally, perhaps crashing in the process. Is there a way to compensate
for that?

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nether
Yes, cyclic control alters the lift distribution within the rotor disk:
[https://en.wikipedia.org/wiki/Helicopter_flight_controls#Cyc...](https://en.wikipedia.org/wiki/Helicopter_flight_controls#Cyclic).
The pilot would apply force to the cyclic to negate any non-uniform ground
effect force.

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oneJob
This, now obvious with hindsight, is the perfect application for other DARPA
developed technologies such as the "robotic feeling hand" recently on HN.
Limiting applications to anthropomorphized form factors is, of course,
extremely limiting.

[http://www.theguardian.com/technology/2015/sep/14/robotic-
ha...](http://www.theguardian.com/technology/2015/sep/14/robotic-hand-wired-
directly-into-brain-feel-again-darpa)

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ntumlin
I've seen videos of large helicopters carrying people hovering with their open
tail end pressed against a hill and the front a few feet in the air, keeping
the whole thing level while dropping people off on the hill, which this could
have done better (less chance for error, less fuel?).

I'm surprised no other helicopters have had something like 4 linear actuators
that a pilot can control to get this same effect with a bit less of the
automation.

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DarkTree
How do helicopters handle in high winds? I'd assume most rescue situations,
such as rough seas and high-altitude, mountainous areas would also be very
windy. I'm curious how the helicopter would hand landing on a 20 degree
incline if the wind were to suddenly blow it a different direction before
touchdown.

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sinaa
In hindsight, it would be hilarious (and perhaps even useful?) if the
helicopter started running on its feet after landing!

Joking aside, given that the legs operate individually, I wonder what happens
in case of a failure in one of them, or when one of them gets damaged during
landing.

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chrisBob
In addition to the use in a regular landing, I see this being a huge benefit
in a hard landing. The helicopters I have been in all had seats that collapse
to absorb energy in a hard landing, and these legs could do the same thing
with a relatively long travel.

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Terr_
Rather than taking the brunt of the landing with expensive/delicate leg
armatures, maybe just swing them back and rely on airbags, e.g.:
[https://www.youtube.com/watch?v=3ewGOXK7tKY&t=0m16s](https://www.youtube.com/watch?v=3ewGOXK7tKY&t=0m16s)

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kyzyl
I'm immediately reminded of the landing gear on the ornithopters from Dune.
Hopefully hunter-seekers are a little further off...

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JumpCrisscross
SpaceX!

