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[dead] fortran77
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lemper
if the constraints are like that, 1 actuator and 2 rigid bodies, i don't think i can find a better solution. so, mighty fine job, i guess?
tnecniv
It’s not physically realizable but the spring-loaded inverted pendulum is arguably the “simplest” walking model. It’s just a mass on a spring.
s1mon
Or there’s always just a spring on an inclined plane or stairs. AKA, a Slinky.
fsckboy
somebody needs to make an animation of a slinky on some Escher staircases.
IshKebab
A spring isn't a rigid body.
zardo
It is an actuator though
Animats
Did they just build this? [1]

The new thing here is that they can steer, by tweaking the motor phase.

[1] https://www.aliexpress.us/item/2251832650580970.html

Someone
That has two legs connected to a body. Theirs has the two legs connected to each other and doesn’t have a body.

It’s a bit nitpicky to call that really different, though. The axle connecting the two legs can be considered a very much shrunken body.

I also suspect that, just like this one, that ancient toy has only one actuator.

jstanley
I think the axle is fixed to one of the legs.
YeGoblynQueenne
>> Fig. 2 illustrates the design of the robot and the key parameters, with design rules given in Table II and the experimental robot’s final parameters given in Table III.

There is no Table II :(

Passive Dynamic Walking is interesting. I remember being really impressed by a video of a pair of legs going down a slope without any mechanical force on the "walker" itself to move them, just gravity and friction, I guess. That was back in 2014, probably. It seems like people have kept working on the concept. I have no way to tell though whether the idea really has cough cough legs, or it will just remain an engineering curiosity that can never be put to real work.

I can't really tell from this paper. Robotics is not my expertise (I work on autonomous navigation and decision-making for robots, but I'm not allowed to go anywhere near the robots. Electronics fry when I'm in proximity).

Edit: collection of passive dynamic walking videos:

https://youtu.be/FfKQSUhYjlY?si=9xGPqYwMeUyIwjqu

jens-c
Table II is just beneath Table I, top of left column on page 2...
YeGoblynQueenne
Thanks. Don't know what happened. I clicked on the hyperlink and still missed it.
pangolinja
I think the Jansen linkage is an awesome way to get very life-like walking motion with minimal complexity
harvie
Well that just sounds like a bristlebot with extra steps.
projektfu
I'm thinking there must therefore be a Zoolander robot that can't turn left.
dcuthbertson
Yes, the design, two rigid bodies connected by a single actuator is very cool. However, it's the eyes that are most striking. The eyes and the rainbow colors. So very pretty. How could one not want to fund further development?