Output Based Iterative Learning Control with Saturation

The paper considers a linear discrete-time system operating in a repetitive mode to track a reference trajectory with a given accuracy. The system parameters are incompletely known and are described by the affine uncertainty model. A new iterative learning control design method based on information about the measured output signal is obtained; this method takes into account the saturation-type nonlinearity inherent in the actuators of robots and allows achieving the required accuracy. The problem statement is motivated by the development trends of high-precision smart and additive manufacturing as well as medical rehabilitation robots. An example illustrates the effectiveness of this method.