This brief considers the iterative learning control (ILC) problem when tracking is only required at a subset of isolated time points along the trial duration. It presents a normoptimal ILC solution to the problem with well-defined convergence properties, design guidelines, and supporting experimental results using an electromechanical test facility. Index Terms— Iterative learning control (ILC), iterative methods, learning control systems, linear systems, motion control, non-minimum phase systems, optimization methods, test facilities. Read more…