Ilian Bonev maintains bibliography and patent databases on parallel mechanisms and much more at ParallelMIC. Access it at the link http://www.parallemic.org/

Parallel Mechanisms information center

The basic properties of robots can developed by studying planar serial chains. Select this link for my notes on elementary robotics:
http://synthetica.eng.uci.edu/~mccarthy/mechanicaldesign101/McCarthyNotes-5.pdf

Elementary Robotics

A copy of my notes on DC motor torque and power can be downloaded at the link:
http://synthetica.eng.uci.edu/~mccarthy/mechanicaldesign101/McCarthyNotes-1.pdf

Motor Torque and Power

The basic principles of DC motors are presented by Joe Wolfe of the University of New South Wales (Sydney, Australia) at the link:
http://www.animations.physics.unsw.edu.au/jw/electricmotors.html

Phyclips from UNSW

Northwestern University (Chicago, Illinois) presents the basics of a DC motor in the Wiki page:
http://hades.mech.northwestern.edu/wiki/index.php/Brushed_DC_Motor_Theory

Northwestern University Wiki page

Joseph Klann provides a useful comparison of the leg designs for his Mondo Spider and Theo Jansen’s Strandbeest at the link:
http://www.mechanicalspider.com/comparison.html

Here is a walking machine called the Mondo Spider:

The leg of this walking machine is described in US Patent 6,260,862 awarded to Joseph Klann. Access it through the link:
http://www.google.com/patents/about?id=70YHAAAAEBAJ&dq=6,260,862

Wikipedia calls this the Klann linkage described here:
http://en.wikipedia.org/wiki/Klann_Linkage

The leg of the mondo spider has the topology known as a Stephenson six-bar.

Theo Jansen builds amazing walking machines as can be seen in this video:
http://www.vimeo.com/3789899

Each leg is an eight-bar linkage. The Wolfram Demonstration Project models this linkage in a Mathematica notebook. See the link:

http://demonstrations.wolfram.com/ATheoJansenWalkingLinkage/