Two Servo Robot?

[Humanoido]

What is the minimum number of servos required to construct a walking robot? There's a two servo design that uses a tilt servo and a stride servo that's been around for some time. More recently, there's been a number of modifications made to the basic design. So if it takes 2 servos to walk, in your opinion, what is the minimum number of servos required to build a humanoid?

It's a valid question as there are many servo controllers that handle a smaller number of servos, and cost considerably less. Here are some examples:

http://www.seetron.com/ssc.htm
http://www.pololu.com/products/pololu/0207/

humanoido

[BillB]

The minumum numberber of servos to create a walking biped is actually zero. The "passive-dynamic walkers" (bipeds that can walk down a gentle slopes powered only by the pull of gravity) are what origionally got me interested in making a biped.

The caveat being that they only work when walking down hill.

I recall reading about simple enhancements to the passive-dynamic walkers that introduced enhanced the design with minimal power - presumably by the addition of only one actuator.

[Pev]

I recall reading about simple enhancements to the passive-dynamic walkers that introduced enhanced the design with minimal power - presumably by the addition of only one actuator.

Yes and I think MIT did some work on it, if memory serves the robot in the middle of these 3 was one of theirs.

http://www.trnmag.com/Photos/2005/022305/Humanoid%20robots%20walk%20naturally%20Image.html

Pev

[Humanoido]

Yes, thank you, and now that you mention it, here's another.

http://www-personal.umich.edu/~shc/robots.html
This is Steve Collins' Home Page: Walking Robots

They speak of injecting a small amount of energy to keep it going.
It compares the actual energy used to walk by various systems.
The results are as follows:

Asimo 3.23
Human 0.20
Cornell Walker 0.20

humanoido