Stability and convergence issues in iterative learning control. II

Repeated accurate path tracking has many control applications. Manufacturing or cycled endurance testing are examples. Repetitions permit adjustments of control signals between cycles with trajectory error information. Iterative learning control (ILC) systems are designed for this situation. Time delays can adversely affect stability especially in iterative schemes. Calculation time by digital systems or by sampling techniques can cause delays. Sensor dynamics or sensor location can also cause delays. This paper proposes a stability condition for ILC where the plant exhibits a time delay.