From: ratinox@splinter.coe.northeastern.edu (Richard Pieri/Stainless Steel Rat)
Newsgroups: rec.games.frp.misc
Subject: Re: Military Mechs? Hexapod
Date: 30 Jul 92 14:53:35 GMT
	<RATINOX.92Jul29101842@splinter.coe.northeastern.edu>
	<1992Jul30.090211.24008@news.Hawaii.Edu>
Organization: 3WA, Boston Office. Or Nu Meta Chi. Take your pick.
In-reply-to: nasato@wiliki.eng.hawaii.edu's message of 30 Jul 92 09:02:11 GMT
X-Get-A-Clue: Have two, they're small.
X-Signature-Virus-Protection: Version 1.51
X-Posting-Software: GNUS 3.14.1 [ NNTP-based News Reader for GNU Emacs ]

>>>>> On 30 Jul 92 09:02:11 GMT, nasato@wiliki.eng.hawaii.edu (Neil Asato)
>>>>> said:

[munch!]

I should point out (again) that the Hexapod is still in the experimental
stages. Much of the design work is prototypical and experimenatal.

NA>      How did they solve the shear stresses that would occur from the
NA> knee to the body? and what about the creep effects (mechanical
NA> engineering term) on the legs? Is the leg an exo-skeleton with the
NA> muscles on the inside like an insect, or on the outside like an
NA> endoskeloton?

The software testbed hexapod uses an hydraulically driven endoskeleton. One
proposed design calls for linear motors around an endoskeleton and inside
an armored exoskeleton.

NA>      How do they perform maintenance work on the muscles (technical
NA> interest, please do not just refference it) (do they have to rest it on
NA> platform, if it can "sit straight down" how does it get up without
NA> ripping up the floor of the maintenance floor and how does it get the
NA> friction to stand up on the legs without just uselessly making furrows
NA> in the ground) ?

The testbed model has a special carriage it sits on when not in use (a few
stacks of cinder blocks :-).

NA>      How much does the tank weigh? How much armor does it have?
NA> How much armor does it have on its various sides (the bottom seems
NA> like an obvious target and would be better protected than a normal
NA> tank)?

It's not a tank, yet. It's mostly a platform with six legs and a ton of
computer equipment (and I'm not kidding about the weight :-). It's
currently walking on it's own control, without being tethered to a
supercomputer.

[other questions relevant to a working, production prototype deleted
because...]

I don't know. It isn't a tank, yet.

NA>      By the way I throw the above questions to anyone who believes that
NA> a legged tank is as good as they seem to make it out to be.  I
NA> personally think any large legged vehicle (massing more than 1000 kg)
NA> would be relatively slow in reality due to stresses (especially shear)
NA> and creep effects if the limbs move fast (thought example: spider tank
NA> has a race with an M-1, after going 100 meters the legs are severely
NA> warped. After 1 kilometer, the spider tank is running on its knees...)
NA> I am interested in what the real world (note the lack of quotation
NA> marks around the two previous words) machines would be like, and it
NA> seems like a lot of people around here are arguing based on solid
NA> knowledge of what the engineering solutions are (or not).

Hard to say. A lot of the answers to your questions are either "under
development" or "sorry, you don't need to know that" (classified). It is
hoped that the Hexapod will be able to reach a speed of around 30-35 mph
walking on its own.

--Rat

||||| | | | |  |  |  |   |   |    |    |    |   |   |  |  |  |  | | | | | |||||
                                                   __        ___ 
Richard Pieri, Northeastern's Stainless Steel Rat/   | /| / /   | The Worlds
Internet: ratinox@meceng.coe.northeastern.edu   /__  |/ |/ / /| | Welfare Works
    UUCP: ...!northeastern.edu!splinter!ratinox/   | /| / / / | | Association:
  BITNET: UA_RLP@NUHUB{.BITNET}               /__  |/ |/ / /  | | I will solve
  USNail: 14 Westdale RD  Holbrook, MA 02343 /   | /| / / /___| | any problem
 ICBMnet: 42 deg 1 min N, 71 deg 0 min W    /    |/ |/ /_//_____| for you.
Newsgroups: rec.games.frp.misc