Unification of dynamic gait generation methods via variable virtual gravity and its control performance analysis

The authors have clarified the mechanism of passive dynamic walking from the mechanical energy point of view, and reported its basic results. This paper then considers the generalization and unification of dynamic gait generation methods by introducing variable virtual gravity concept and some solution formulas as well as essential mechanical energy orbits. As two leading methods, energy tracking control and virtual passive dynamic walking are considered, and we analyze the control performances of robust stability and energy-efficiency criterions by numerical simulations. Finally we discuss the application possibility of the methods to actual walking machines from the ZMP point of view.