Mechanical horses

[GregLocock]

http://italy.greyfalcon.us/THE DOBBIN.htm

I'm referring to the one on the right.

Do you think that it actually moved? How did the drive get to the rear axle? Then what happens?

Have you seen any other 4 legged machines along similar lines?

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[KENAT]

Too modern to be history but Boston Dynamics Big Dog is impressive.

http://www.youtube.com/watch?v=W1czBcnX1Ww

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

 

[btrueblood]

"Do you think that it actually moved? "

No, looks like either a static rig, or (more likely) an "artist's rendering"

"How did the drive get to the rear axle?"

Can't see any drive to rear end. Thus #1 answer above.

"Then what happens?"

It would fall over on the first step?... unless gyro-stabilized? Nowadays it would be controlled by some kinda bit-crunching gizmo to stay up.

"Have you seen any other 4 legged machines along similar lines? "

Yeah, somebody posted a 4-legged "mule" video (with bystanders kicking it and it "trotting" to maintain balance)in ... the automotive? mechanical? forum awhile back. It is apparently the product of a DARPA initiative.

 

[MikeHalloran]

The front axle looks like a simple gearbox with quartered output cranks driving enormously complicated 'shoulder' linkages.

The rear links seem less finished than those in the front, suggesting perhaps they were in development. There doesn't seem to be much of a backbone, and what there is, is curved. It _could_ house a flexible shaft, but I don't see an after gearbox. I can't quite see how exactly, but I'm thinking maybe the rear is driven passively, i.e. by being pulled along by the front and rocked from side to side.



Mike Halloran
Pembroke Pines, FL, USA

 

[GregLocock]

KENAT, ah I'd forgotten about that Big Dog thing, fantastic to see it in action.

Yes Mike, my guess was the front legs may have actually managed some sort of walking type motion, though the joints look a bit light for real work.

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[C2it]

Att-atts seemed to do ok in the Star Wars movie ...

 

[KENAT]

Fantastic, but somehow slightly creepy. Not sure why but just seems that way to me.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

 

[GregLocock]

The bit where it staggers around on the ice looks just like a new born foal. I suppose it is 'obvious' that if you have a certain cg height, and similar set of legs and joints, that the motion will be similar. But as you say, slightly freaky to see a machine reacting in such a familiar fashion.

It really needs boots!

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[SomptingGuy]

It must have some kind of really clever state machine inside that flips between walking and self-preservation modes. You can see that when it's kicked, it stumbles, rights itself and then starts walking again. There's no attempt to make progress while righting itself.

The hill climbing and hill descending modes looked distinctly different too, as did the climbing over the bricks mode.

- Steve

 

[BJC]

Hanibel could have used these.

http://www.videosift.com/video/Giant-mechanical-elephant-giving-people-rides