  We show via examples that, when solving optimal control problems,
representing the optimal state and input trajectory directly using
interpolation schemes may not be the best choice. Due to the lack of
considerations for solution trajectories in-between collocation points, large
errors may occur, posing risks if this solution is to be applied. A novel
solution representation method is proposed, capable of yielding a solution of
much higher accuracy for the same discretization mesh. This is achieved by
minimizing the integral of the residual error for the overall trajectory,
instead of forcing the errors to be zero only at collocation points. In this
way, the requirement for mesh resolution can be significantly reduced, leaving
the problem dimensions relatively small. This particular formulation also
avoids some of the drawbacks found in the earlier work of integrated residual
minimization, leading to more efficient computations.
