Leg design

I've chosen a 3 DOF (degrees of freedom) leg because this is sufficient to place the tip of the leg (i.e. foot) anywhere in a bounded 3D space. I will be able to control how far forward, out from the body, and up in the air the leg is. 4 DOF would be cool but the servo count (and therefore the weight) would be high as would the complexity of the control algorithms. The three degrees of freedom are:

* Swing (leg backwards/forwards), driven by AX-18A servo

* Hip (lifting of the entire leg up and down), driven by AX-12A servo

* Knee (lifting of the lower half of the leg), driven by AX-12A servo