46 replies to this topic

[bobobobobiy]

So, this has always been sorta on my mind, but is there any actual advantage/disadvantage to having chicken legs ex: stalker, cataphract rather than humanoid legs ex: jager? Not gameplay-wise, but mechanically and practically?

Also, wouldn't having bent chicken legs always put immense stress on the bent joint?

[Juodas Varnas]

edit: Never mind, you meant not gameplay-wise.

Edited by Juodas Varnas, 11 June 2015 - 12:20 PM.

[CDLord HHGD]

Edit: Nevermind. I thought I knew what I was talking about. Apparently not....

Edited by cdlord, 12 June 2015 - 07:37 AM.

[GeistHrafn]

bobobobobiy, on 11 June 2015 - 12:17 PM, said:

Also, wouldn't having bent chicken legs always put immense stress on the bent joint?

Have you ever seen an Ostrich run or attack? Weak knees is not my first thought when I think of them...

[Zeusus]

Chicken legs support less load but are way faster, humanoid can support more because the weight it directly on the support, but it won't move as quickly.

My horse is a great example. Weight to front when being lazy but weight shifts back to go fast.

[bobobobobiy]

Yeah, it does seem like humanoid legs can support more weight. They also seem to be great for pushing off the ground.

Chicken legs seem more like support legs on quadrupeds when they run, and the ostrich is a mystery to me.

But yeah, many runners seem to have humanoid legs with "raised" heels, and I don't see how pure reverse bent legs could be good for anything.

And again, the ostrich is a mystery.

[stjobe]

"A chicken walker is a fictional type of bipedal robot or mecha, distinguished by its rear-facing knee joint. This type of articulation resembles a bird's legs, hence the name. However, birds actually have forward-facing knees; they are digitigrade, and what most call the "knee" is actually the ankle.

They are usually less able to handle extremely rugged terrain than "man walkers". They are often shown to be faster than other robots, capable of roadrunner-like movements. The best example of this contrast in film is the fast pursuits of the ED-209 versus the steady walking pace of RoboCop in the RoboCop franchise. Also, in the Star Wars franchise, the chicken-walking AT-ST was used as a light scout vehicle rather than the AT-AT, which were lumbering quadrupeds."
- http://en.wikipedia..../Chicken_walker

[Hit the Deck]

I can't think of any real world animals which have "chicken legs" (reversed knees) like those depicted in fiction. So it's kinda hard to make comparison because you need to imagine how these "chicken legs" function.

EDIT: ninja'ed by stjobe!

Edited by Hit the Deck, 11 June 2015 - 12:46 PM.

[bobobobobiy]

Well yeah, no animal actually has reversed knees like in MWO, but instead rely on calf muscles and [heel muscles?] more as well as quads.

[SilentSooYun]

Bird legs look cooler!

...I got nuthin'

Well, actually... the new Crab looks to have proper digitigrade legs, which I am VERY much looking forward to. Not only does digitigrade look even cooler (all the best dinosaurs had them ), but it puts the weight over what amounts to a coiled spring, suggesting faster movement, better terrain handling, and easier direction shift. The downside is that it's not very energy efficient, moving additional long-myomer groups... humanoid legs basically work by pushing forward and catching yourself before you fall, which is one of the most efficient systems for bipedal movement. Plus humanoid movement is what we humans are used to (duh), so neuralhelmet attunement takes a fraction of the time it does a chicken-walker.

Edited by SilentSooYun, 11 June 2015 - 01:13 PM.

[bad arcade kitty]

'chicken legs' have knees too

catch a dog
investigate its hind leg:
that round part at the very top which is pointed ahead it's its knee
that pointy thingy which is pointed backwards it's its heel
and what you think is its foot is actually its toe

[stjobe]

There's three types of leg structure in terrestrial animals: Plantigrade (e.g humans), digitigrade (e.g. dogs and birds), and unguligrade (e.g.horses):



Please note that the knee is not reversed in any of these leg structures.

As has been observed a number of times in this thread there's no natural occurring analogue for the "chicken walker" leg with its reverse knee joint.

Edited by stjobe, 11 June 2015 - 01:10 PM.

[Alistair Winter]

Zeusus, on 11 June 2015 - 12:36 PM, said:

Chicken legs support less load but are way faster, humanoid can support more because the weight it directly on the support, but it won't move as quickly.

My horse is a great example. Weight to front when being lazy but weight shifts back to go fast.

Your horse runs on its hind legs? That's ******* awesome!

[CDLord HHGD]

Alistair Winter, on 11 June 2015 - 01:12 PM, said:

Your horse runs on its hind legs? That's ******* awesome!

[SilentSooYun]

stjobe, on 11 June 2015 - 01:10 PM, said:

As has been observed a number of times in this thread there's no natural occurring analogue for the "chicken walker" leg with its reverse knee joint.

Crickets
Also, some types of cockroaches actually rear up on their hind legs to run. Can't find a video, cause I want to see that myself.

[bad arcade kitty]

a petition to rename chicken legs to insect legs :3

[Nothing Whatsoever]

Ostrich legs are best. They can sustain speeds up to 31 mph / 49.9 kph running.

[bad arcade kitty]

Praetor Knight, on 11 June 2015 - 01:26 PM, said:

Ostrich legs are best. They can sustain speeds up to 31 mph / 49.9 kph running.

well, a human can run up to 44.7 kmh
not much worse than an ostrich

http://en.wikipedia.org/wiki/Footspeed

[stjobe]

bobobobobiy, on 11 June 2015 - 12:17 PM, said:

is there any actual advantage/disadvantage to having chicken legs ex: stalker, cataphract rather than humanoid legs ex: jager? Not gameplay-wise, but mechanically and practically?

"The primary advantages of a plantigrade foot are stability and weight-bearing ability; plantigrade feet have the largest surface area. The primary disadvantage of a plantigrade foot is speed. With more bones and joints in the foot, the leg is both shorter and heavier at the far end, which makes it difficult to move rapidly."
- http://en.wikipedia....iki/Plantigrade

Human - 30 mph (plantigrade)
Ostrich - 40 mph (digitigrade)

There's no bipedal unguligrades AFAIK, but:
Antelope - 55 mph (unguligrade)
Cheetah - 60 mph (digitigrade)

Praetor Knight, on 11 June 2015 - 01:26 PM, said:

Ostrich legs are best. They can sustain speeds up to 31 mph / 49.9 kph running.

A bit faster than that; they can top 43 mph (70 kph).

Edited by stjobe, 11 June 2015 - 01:30 PM.

[9erRed]

Greetings all,

As a real world example of a 'chicken walker' robot.




Notice that for a few of the 'recovery' steps this chassis has or can have a very long stride. Also balance vertically and horizontally can be managed much easer with simple lowering or extending of either or both legs.

- The chicken walker design normally has the benefit of more length combined within the sections of the legs, compared to a biped 'man legs' design. (in most cases)
- Using compression and mechanical advantage this design should be able to 'absorb' greater down forces for landings and running jumps.
- This 'powered leg' design is somewhat old tech, now. The latest MIT cheetah design has the jumping down pat and can still land and keep running. See here:


Or the newest 'Spot' all electric version, designed for interior as well as exterior work.


Just some info and ideas,
9erRed

Edited by 9erRed, 11 June 2015 - 01:34 PM.