A passive 2DOF walker: Finding gait cycles using virtual holonomic constraints

— A planar compass-like biped on a shallow slope is the simplest model of a passive walker. It is a two-degrees-offreedom impulsive mechanical system known to possess periodic solutions reminiscent to human walking. Finding such solutions is a challenging task. We propose a new approach to obtain stable as well as unstable hybrid limit cycles without integrating the full set of differential equations. The procedure is based on exploring the idea of parameterizing a possible periodic solution via virtual holonomic constraints. We also show that a 2-dimensional manifold, defining the hybrid zero dynamics associated with a stable hybrid cycle, in general, is not invariant for the dynamics of the model of the compass-gait walker.

• Type: Conference
• Year: 2008
• Where: CDC
• Authors: Leonid B. Freidovich, Uwe Mettin, Anton S. Shiriaev, Mark W. Spong
• Keywords: CDC 2008, Control Systems, Hybrid Zero Dynamics, Periodic Solution, Unstable Hybrid Limit