Why do most hexapods have this leg design ?

[bilals]

Hello, i suppose there are mechanical advantages for having this leg design in a hexapod? what are the advantages? :

[KurtEck]

I am not sure if your question is why most/many hexapods have legs with three degrees of freedom, or if you are asking about this particular look. 

If it is the look, I think a lot of people possibly starting with the MicroMagic stuff and later with Xan with his phoenix and the like made it look like this because of the look. Also these legs also have a good range of motion.

Mechanically some of the other leg designs like some of these from Lynxmotion:

or


have a mechanical advantage of being able to support more weight as the brackets supports both ends of the servos and does not put all of the stress at the servo horns. 

Kurt

[bilals]

What I meant was why do they have this shape:



Why do they have the shape outlined in (YELLOW)? Why are they hollow? Is it to reduce the weight?

And now that you mention it (3 DOF). This is be more flexible, performing more moves, right ?

[KurtEck]

As I mentioned before I think a lot of the designs were influenced by Matt Denton of Micro Magic Systems (http://www.micromagicsystems.com/#/robotics/4515986498). 

The left hand side of the image is probably mostly for looks.  The right hand curves allow the legs to be moved in close to the body.  The points at the end allow the robots to turn.  Probably being hollow is mostly for weight but with some of the lynmotion legs, it also allows you to add lights to them which look nice:

There are probably other reasons that I am missing.

Kurt

[bilals]

Thanks KurtEck for helping