I’ve seen obese people walk like this. It’s a waddle, done by rotating / thrusting the hips first to the left, then to the right, and the corresponding leg will follow.

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?

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.

Or there’s always just a spring on an inclined plane or stairs. AKA, a Slinky.

somebody needs to make an animation of a slinky on some Escher staircases.

s/somebody/some AI/

A spring isn't a rigid body.

It is an actuator though

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

We can't see what you posted, because it does not ship to our location.

It's a windup toy robot, resembling something like a retro vintage version of the robot emoji, and I assume the legs march the robot around after being wound up

Is it this, which seems to load: https://ae01.alicdn.com/kf/HTB1KdbgOFXXXXbyXVXXq6xXFXXXT/Fre...

Yes. Or it's similar enough that the images look the same to me.

[delayed]

I think the axle is fixed to one of the legs.

No, they built this:

https://susquehannavalley.blogspot.com/2019/10/wilson-walkie...

FTA:

>> We base our robot on classic passive dynamic walking toys like the Wilson Walker [12].

>> 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

Table II is just beneath Table I, top of left column on page 2...

Thanks. Don't know what happened. I clicked on the hyperlink and still missed it.

This video would deserve its own submission!

[delayed]

I think the Jansen linkage is an awesome way to get very life-like walking motion with minimal complexity

Well that just sounds like a bristlebot with extra steps.

Not the same mechanism but another simple single-motor/continuous-motion walker in lego https://www.youtube.com/watch?v=Nt2DszsjmQM .. The guy has a couple other walkers..

I used to have a modest claim to fame in the niche world of Lego biped walkers with a similar design, some 20 years ago.

https://www.youtube.com/watch?v=yKioQefwKWQ

Nice one! Very neat.

Thanks!

I'm thinking there must therefore be a Zoolander robot that can't turn left.

Photo here: https://i.imgur.com/GmIccbL.jpg

From https://arxiv.org/pdf/2308.08401.pdf

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?