An optimal control problem is studied, in which the state is required
to remain in a
compact set S. A control feedback law is constructed which, for
given ε > 0, produces ε-optimal trajectories that satisfy the
state constraint universally with respect to all initial conditions
in S.
The construction relies upon a constraint removal technique which
utilizes geometric properties of inner approximations of S and a
related trajectory tracking result.
The control feedback is shown to possess a robustness property with
respect to state measurement error.
