Will Moon Robot Fly?

On Nov 3, 3:46*pm, Hop wrote:

A telerobot with two cameras giving stereo vision, a head that mimics
the motion of the users head, as well as arms and hands that mimics
the users hands could be useful. I would expect these to be put on
wheels though.

Wheels are great for relatively smooth terrain. Legs usually work
better when there are lots of rocks and holes.

Bipedal transportation needs a sense of balance.

I'd expect a legged lunar robot to be a tetrapod at least, or perhaps
something akin to a centaur. Two legs aren't enough to deal with
random ruggedness; it's too easy to step into a hole that you didn't
know was there before you committed your weight to that foot.

Maintaining balance is a problem that a user with a 3 second light lag
wouldn't be able to deal with.

That's what autonomous balance software is for. It's already being
used for "packbot" applications for which control lag is not an issue.

In sci.space.policy message 58537e06-e420-48ed-8a08-cea56a205b48@a37g20
00yqi.googlegroups.com, Thu, 4 Nov 2010 08:45:19, Alan Anderson
posted:


I'd expect a legged lunar robot to be a tetrapod at least, or perhaps
something akin to a centaur. Two legs aren't enough to deal with
random ruggedness; it's too easy to step into a hole that you didn't
know was there before you committed your weight to that foot.


It should have six legs, so that while walking it stands stably on three
feet while moving the other three in the direction of travel. The feet
should be wheels, for the flat ground. Look up, if necessary,
ATHLETE_(robot) in Wikipedia.

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Web http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms and links;
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On Nov 5, 7:38*pm, Dr J R Stockton
wrote:
It should have six legs, so that while walking it stands stably on three
feet while moving the other three in the direction of travel.

Six legs simplifies the task of balancing greatly, to the point where
you don't need any special feedback or fancy motion to remain stable
on relatively level ground. However, given that you still need that
feedback and fine control to deal with unpredictable terrain and
obstacles, four legs are sufficient. Goats do just fine without six
legs, for example.

Tiny robots can have much longer and skinnier legs by comparison, and
can use the leverage to take advantage of the inherent stability while
not paying much penalty in mass or motive power requirements. Huge
robots benefit from spreading the weight over more legs at the same
time, though the legs themselves end up being a much larger fraction
of the entire object. But at a reasonably large range of masses, once
you require a certain amount of freedom in leg motion, more than four
merely adds unnecessary complexity.

On 11/6/2010 10:35 AM, Alan Anderson wrote:

Six legs simplifies the task of balancing greatly, to the point where
you don't need any special feedback or fancy motion to remain stable
on relatively level ground.

Let's see...six legs...two maniptulatory hands/arms mounted on a torso
set at ninety degrees to the part with the legs on it...with a rotating
head atop the torso..where have I seen something like this before?:
http://www.rumormillnews.com/pix3/pic100705.jpg
Oh, ****. ;-)

Pat

Alan Anderson ) writes:
On Nov 5, 7:38=A0pm, Dr J R Stockton
wrote:
It should have six legs, so that while walking it stands stably on three
feet while moving the other three in the direction of travel.

Six legs simplifies the task of balancing greatly, to the point where
you don't need any special feedback or fancy motion to remain stable
on relatively level ground. However, given that you still need that
feedback and fine control to deal with unpredictable terrain and
obstacles, four legs are sufficient. Goats do just fine without six
legs, for example.

Tiny robots can have much longer and skinnier legs by comparison, and
can use the leverage to take advantage of the inherent stability while
not paying much penalty in mass or motive power requirements. Huge
robots benefit from spreading the weight over more legs at the same
time, though the legs themselves end up being a much larger fraction
of the entire object. But at a reasonably large range of masses, once
you require a certain amount of freedom in leg motion, more than four
merely adds unnecessary complexity.

Don't have the url handy, but a few years back there were videos on the web
of DARPA's Big Dog robot that moved across rough terrain, righted itself
after being pushed off-balance and could jump over obstacles (all on four
legs).

--John Park

On 11/7/2010 9:55 AM, John Park wrote:

Don't have the url handy, but a few years back there were videos on the web
of DARPA's Big Dog robot that moved across rough terrain, righted itself
after being pushed off-balance and could jump over obstacles (all on four
legs).

That's over he
http://www.youtube.com/watch?v=cHJJQ0zNNOM
I find that thing highly disturbing, like if a headless horse showed up
on your doorstep someday.
If you check out the video at around the 1:40 mark it looks for all the
world like two people's lower torsos and legs facing each other.
Apparently, its engine is so loud you can hear it coming from around a
mile away.
Get ready for the Robomatadors:
http://www.youtube.com/watch?v=ptyV1cpE14o&NR=1
You stick a sword into that thing and you are probably going to get
electrocuted. :-D

Pat

On 11/7/2010 9:22 PM, Pat Flannery wrote:

That's over he
http://www.youtube.com/watch?v=cHJJQ0zNNOM

Is there some reason it has to be all-black?
I mean, it looks like something that would show up in a nightmare after
you fell asleep after reading H.P. Lovecraft stories during a thunderstorm.
The thing is "unwholesome" at a deep and profound level, and frankly, I
would prefer dealing with something like Nyarlathotep rather than that
mechanical monstrosity.

Pat

On Nov 8, 2:42*am, Pat Flannery wrote:

Is there some reason it has to be all-black?

It is somewhat reminiscent of a housefly, isn't it? Perhaps America's
enemies are "a cowardly and superstitious lot".

John Savard

In sci.space.policy message c41f5d96-cace-4d51-942d-9f61f8d34c01@x4g200
0pre.googlegroups.com, Sat, 6 Nov 2010 11:35:25, Alan Anderson
posted:

On Nov 5, 7:38*pm, Dr J R Stockton
wrote:
It should have six legs, so that while walking it stands stably on three
feet while moving the other three in the direction of travel.

Six legs simplifies the task of balancing greatly, to the point where
you don't need any special feedback or fancy motion to remain stable
on relatively level ground. However, given that you still need that
feedback and fine control to deal with unpredictable terrain and
obstacles, four legs are sufficient. Goats do just fine without six
legs, for example.

A system with six legs is not obliged to use all of them all of the time
if it can be designed to do better sometimes with fewer in use and the
others raised.

It should be able to manage quite well with one leg failed, with two
failed unless unlucky, and with three failed if lucky. Clearly there
should be a means whereby a failed leg can be raised or cut off.

--
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Web http://www.merlyn.demon.co.uk/ - FAQish topics, acronyms, and links.
Proper = 4-line sig. separator as above, a line exactly "-- " (RFCs 5536/7)
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Eight Legs
http://www.youtube.com/watch?v=gNXuzhop-u8

Zero Legs
http://www.youtube.com/watch?v=QhWR0...eature=related