  We study the existence of asymptotically stable periodic trajectories induced
by reset feedback. The analysis is developed for a planar system. Casting the
problem into the hybrid setting, we show that a periodic orbit arises from the
balance between the energy dissipated during flows and the energy restored by
resets, at jumps. The stability of the periodic orbit is studied with hybrid
Lyapunov tools. The satisfaction of the so-called hybrid basic conditions
ensures the robustness of the asymptotic stability. Extensions of the approach
to more general mechanical systems are discussed.
