  We consider a system that is exactly controllable. For given initial state,
terminal state and objective function, an optimal control is often
well-defined. Such an optimal control has the disadvantage that although it
works perfectly well for the given initial state, for a perturbed initial state
it often does not make sense. In this talk we present a concept to obtain
robust control schemes by the combination of the optimal control with a
stabilizing feedback law. In this way, also for perturbed initial states the
system is controlled in a reasonable way. In the talk we focus on the boundary
control of the wave equation. However, our concept is applicable to the control
of general time-dependent systems.
