Modeling Robotic Bipedal Walkers

Our models are derived using exponential twists (relative axes) and Lagrangian dynamics (see Murray, Li, Sastry). In the following list, each model is a more general version of the prior, which is easily implemented using the techniques outlined in MLS.

We then convert our current model of interest, the 3-D Hipless Walker without Yaw, into the more familiar "static" coordinate system. This only affects the planar variables of stance pitch and non-stance pitch, so that they resemble the theta angles from the Literature. In fact, the 2-D plane is still relative to the lean specified by the roll angle, phi. After performing the transformation, we implement our control law for flat ground walking and lean compensation via potential shaping.