  Inactive constraints do not contribute to the solution of an optimal control
problem, but increase the problem size and burden the numerical computations.
We present a novel strategy for handling inactive constraints efficiently by
systematically removing the inactive and redundant constraints. The method is
designed to be used together with simultaneous approaches under a mesh
refinement framework, with mild assumptions that the original problem has
feasible solutions, and the initial solve of the problem is successful. The
method is tailored for interior point-based solvers, which are known to be very
sensitive to the choice of initial points in terms of feasibility. In the
example problem shown, the proposed scheme achieves more than a 40% reduction
in computation time.
