A four degree of freedom leg for a walking robot has been modeled using Newton's method. Unlike robot manipulators, which have a fixed base, a leg model must include inertial forces due to base motion. These forces have been included in the formulation. These equations can be used for design, simulation, and control. The inverse kinematics for this leg are also presented. This allows the joint angles to be computed from a desired foot-hold position.
Wright, Andrew B.
"Derivation of Equations of Motion for a Four Link Robotic Leg for a Walking Vehicle,"
Journal of the Arkansas Academy of Science: Vol. 53
, Article 24.
Available at: http://scholarworks.uark.edu/jaas/vol53/iss1/24