— Two feedback controllers that induce stable running gaits on a three-degree-of-freedom asymmetric hopper, termed the Asymmetric Spring Loaded Inverted Pendulum (ASLIP), see Fig. 1, are compared in terms of their steady-state and transient behaviors. In each case, feedback is used to create a lower-dimensional hybrid subsystem that determines the existence and stability properties of periodic motions of the full-dimensional closed-loop system. The first controller creates a one degree-of-freedom subsystem through imposing two suitably selected (virtual) holonomic constraints on the configuration variables of the ASLIP. The second controller asymptotically imposes a single (virtual) holonomic constraint to create a two-degree-of-freedom subsystem that is diffeomorphic to a standard Spring Loaded Inverted Pendulum (SLIP). The two controllers induce identical steady-state behaviors. Under transient conditions, however, the underlying compliant nature of the SLIP allows significantly la...
Ioannis Poulakakis, J. W. Grizzle