199 replies to this topic

[Fuzzbox]

Just take a look at any bird or any dog/cat walking on their hind legs.

Us humans are freaks...

[granpajo]

It has hips and knees man. Here are a few ones I dug up an annotated.

Red arrow shows hip joint
Green shows knee.









In these mechs, most of the torque required for forward motion is provided in the pelvic region. Foot extends along the hip and knee, comes down, pelvic region rotates backwards to provide forward motion.

Semi-decent if lacking the pelvic motion animation.

[Raalic]

MAGNETS, HOW DO THEY WORK?

[Bishop Steiner]

Keisuke Nagisa, on 14 February 2013 - 10:19 AM, said:

Ok so you are proving that birds have knees as I just did. Whats your point. In the old artwork mechs don't have knees. Thats the point. Without knee's walking and running ability is crippled. A point recent artwork of new mechs has rectified.

The "extra motion of the hip" is provided by where the knee is located. Without that knee the ostrich would have to rely on only its ankle and toes to push against the ground. Its hip would only be able to swing back and forth and wouldn't be able to create much force.:

Which mech didn't have knees? (aside from the abominations from the 3055 and 5058 TROs, possibly, NONE of which are even in this game)

granpajo, on 14 February 2013 - 11:05 AM, said:

It has hips and knees man. Here are a few ones I dug up an annotated.

Red arrow shows hip joint
Green shows knee.









In these mechs, most of the torque required for forward motion is provided in the pelvic region. Foot extends along the hip and knee, comes down, pelvic region rotates backwards to provide forward motion.

Semi-decent if lacking the pelvic motion animation.

Thanks. Saved me the work. Of those, the only one that I find flat out non-feasible would be the Marauder, since the upper leg and hip section is far too small.. And the Penetrator. Shame such a hideous mech has such a great payload. The King Crab has far greater issues, as does the Stalker, but neither are the leg design. And the Crab very specifically does have knees. One doesn't need a huge industrial external gear.

Edited by Bishop Steiner, 14 February 2013 - 11:23 AM.

[Carnivoris]

There is a gyro in the engine and the pilot is hooked up to a neurohelmet that transmits balance information to the pilot's brain and back again. This is how mechs can do advanced balancing tricks (ie, anything except walking on flat land).

http://www.sarna.net/wiki/Neurohelmet

Edited by Carnivoris, 14 February 2013 - 11:47 AM.

[Suprentus]

Seanamal, on 14 February 2013 - 02:38 AM, said:

Well the motions are all really the secondary issue of why mechs won't work. Ground pressure. A mech standing still is exerting close to 800 psi. When it's walking it's closer to 1600 psi. When running It might hit as much as 3000 psi! So unless it's running on reinforced tarmac or solid granite as soon as it starts moving fast it's going to bury it's leg to it's knee. Heaven help you if you are on mud.

Thontor, on 14 February 2013 - 05:50 AM, said:

Ok... I might be wrong here... But lets assume a mech 10x as large as a 1.8 meter, 90 kilogram (5' 9", 198 lb) man with the same density and proportions. Kinda heavyset... But not obese.

Guess what it comes out to? 90 tons

Now, lets assume this man has feet 3 inches by 12 inches for ease of calculation... so 36 square inches per foot.. 72 square inches for both.

A mech 10x bigger in all dimensions would therefore have 7200 square inches of foot contacting the ground when standing (30*120)

90 tons = 198,416 pounds

198,416 / 7200 = 27.55 pounds per square inch, 55.11 if it is all on one foot.

(For reference that man mentioned earlier would be 2.755 psi, 5.511 if all on one foot... Interesting that even though this mech weighs 1,000 times as much as the man, since it's feet have 100x the area, the psi exerted only comes out to 10x, same as the height relationship)

a far cry from the numbers you gave

I put together a different number based on different variables, just so that we can look at it from multiple angles.

Let's assume that the footprint of only 1 foot of a Mech is 1 square meter. To put that in perspective, here's a square meter:



Likely a footprint is bigger, but let's just shrink it down to a square meter anyway. Even if an Atlas is standing on only 1 foot, we can say that's 100 tons per square meter. Well converted to psi, that's only about 142 psi, and that's only if it's standing on one foot.

Try it yourself and just put 100 tons per square meter in and see what you get.

http://www.convertun...per+square+inch

It's more than Thontor came up with (although with a smaller footprint than is likely), but like he said, it's still a far cry from the numbers (800 psi, 1600 if standing on one foot) Seanamal came up with.

Edited by Suprentus, 14 February 2013 - 11:58 AM.

[Havyek]

People posting these types of threads are the reason warning labels exist. . . . .

[Tickdoff Tank]

uebersoldat, on 14 February 2013 - 09:10 AM, said:

Wait wait wait, MW4 had the rearcam. Give them time, we'll have them I'll wager.

Unfortunately, the Cryengine 3 has problems with rendering 2 separate fields of view. Cryengine can do it, but it basically doubles the processor load, which would cause huge amounts of lag. I am sure that the answer is far more technical than what I just posted, but I think that conveys the basics of why we do not (and most likely will not) get a rear facing camera.

[Garth Erlam]

http://en.wikipedia....ki/Bird_anatomy

[Tickdoff Tank]

Garth Erlam, on 14 February 2013 - 12:22 PM, said:

http://en.wikipedia....ki/Bird_anatomy

So, you are saying that mechs walk like birds, birds are ancestors of dinosaurs and therefore we are piloting mechanized dinosaurs. Got it. Thanks for clearing that up.

http://tvtropes.org/...nsaneTrollLogic

[Kunae]

Garth Erlam, on 14 February 2013 - 12:22 PM, said:

http://en.wikipedia....ki/Bird_anatomy

http://en.wikipedia..../Insect_anatomy

[Bishop Steiner]

Garth Erlam, on 14 February 2013 - 12:22 PM, said:

http://en.wikipedia....ki/Bird_anatomy

btw, owe you an apology. (or was it Paul?). Just cored out a fully healthy AS7-K in 2 volleys (just about 3 seconds) of 4 medium pulse lasers, 2 srm 4. 80 pts or so, concentrated on rear CT. (of course I could only move 100 kph). So, it CAN be done, but any other light or medium would ate my cookies in the process. (and still not 100% sure what that has to do with DHS.. or was it ECM that was the issue? *shrugs*)

Edited by Bishop Steiner, 14 February 2013 - 12:30 PM.

[stjobe]

Bah, who needs more than one joint anyway?



Although having some can make you go faster (18 mph is the new speed record for robots):



Ah, Boston Dynamics.... They do some really cool stuff:



Although they're a bit more serious than these guys:

http://www.youtube.c...1&v=WTHI8o5ZOFk

(how many joints was that on each leg? Two?)

[M4NTiC0R3X]

[DrxAbstract]

I dont see the human leg operating in reverse in as a good example; Usually when people do this, their ankle elevates and their toes meet the ground, functioning exactly like a chicken's leg.

Chickenwalkers in Battletech function because the hip, waist and opposing hip all act as a replacement for the 4th, uppermost joint of a chicken's leg, removing the need for a 4th joint in the mech's leg.

When the mech's leg moves forward, the waist moves forward at an angle in the same direction, creating a 'sway'. In essence the opposing hip acts as the forward compensatory joint and chickenwalkers move with an alternating, swaying gait. You can see this very clearly in Mech4 with the Mad Cat at a run.

It is entirely possible.

http://youtu.be/vwcKyXjTrpI - good view, watch the waist.

Edited by DrxAbstract, 14 February 2013 - 12:59 PM.

[Knobby]

Biologist chiming in here:

Warrax the Chaos Warrior, on 13 February 2013 - 02:59 PM, said:

Also, they walk like birds, which are really really light weight, but it works for giant metal mechs too apparently.

Ostriches are pretty heavy, and the prehistory has seen even bigger and heavier birds, as well as big raptors (dinosaurs) with the same configuration. Weight is not really a factor

One Medic Army, on 13 February 2013 - 03:01 PM, said:

Look at the rear legs of a quadrupedal mamal, or the legs of a bird.
They work like that.

Actually they don't, OP's diagram is correct.

Mechs are missing a thighbone (femur) and knee.
What most ppl would identify as the shinbone in birds is actually the foot, they actually stand on their toes.
The confusing part is that the thighbone and knee are often partly inside the body itself so not always easily visible from the outside

http://fsc.fernbank....ng/skeleton.htm

Edited by Knobby, 14 February 2013 - 01:11 PM.

[Keisuke Nagisa]

Ok Again for the people that are not getting it:

Red = Hip
Green = Knee
Blue = ankle
Black = toe
Yellow = weird extendo leg

This is our base. This is what evolution has deemed the best setup for maximum speed and acceleration.


This is a crab. It clearly has no knee's. What it does have (and other mechs look like they may have) is the ability to extend its foot like a hydraulic, making up for the movement it loses by having no knee.


This is a locust. You can see it also has no knee. The protrusion out the back of its ankle look like it may have to ability to extend its foot. A lot of "no knee" mechs have similar protrusions.


This is a catapult. This is one of the mechs that seem to have its joints reversed (that or is has an extra bone above the femur). As far as I know there are no examples in nature illustrating whether or not this design would be effective.


Now This is a recent mech design, an SC Wight. This is what a mech with bird like legs should look like, and what most recent mechs with this leg design look like. In this picture of it running you can clearly see how much more force it would be able to creat by pushing its leg back and extending it other leg forward for long sprinting strides.


If you watch this madcat running video you can see it doesn't so much run as it hops from leg to leg. Balance would be an issue in a design like this.


Now a mech COULD walk without knees like the ones pictured but it would not be very efficient and running would be hard.

[stjobe]

Keisuke Nagisa, on 14 February 2013 - 01:57 PM, said:

This is a locust.

Sorry man, but that's not a Locust. This is a Locust:

[Keisuke Nagisa]

stjobe, on 14 February 2013 - 02:16 PM, said:

Sorry man, but that's not a Locust. This is a Locust:

Thats an unseen locust. I posted a reseen locust. The official BT forum has a policy of not posting unseen art for legal reasons. This forum may have a similar policy since it is an official entity for the Battletech/MechWarrior franchise. Harmony gold is very **** about these things so I would say it is not allowed.

Edited by Keisuke Nagisa, 14 February 2013 - 02:24 PM.

[Bishop Steiner]

Keisuke Nagisa, on 14 February 2013 - 02:22 PM, said:

Thats an unseen locust. I posted a reseen locust. The official BT forum has a policy of not posting unseen art for legal reasons. This forum may have a similar policy since it is an official entity for the Battletech/MechWarrior franchise. Harmony gold is very **** about these things so I would say it is not allowed.

considering the hundreds of times the Unseen art has been posted on this Forum, I can say that we are in no particular danger.