Asymptotically optimal feedback control for a system of linear   oscillators
  Problem of damping of an arbitrary number of linear oscillators under common bounded control is considered. We are looking for a feedback control steering the system to the equilibrium. The obtained control is asymptotically optimal: the ratio of motion time to zero with this control to the minimum one is close to 1, if the initial energy of the system is large. Some of the results based on the new lemma about sustainable observability autonomous linear systems. 
Alexander Ovseevich, Aleksey Fedorov
math.OC math.DS