Identification and control of electrohydraulic actuator modeled as a linear periodic system

In the tracking of periodic signals, the nonlinear dynamics of electrohydraulic actuators are modeled as linear periodic systems perturbed along periodic input and output trajectories. System identification of linear periodic systems is first performed and then periodic repetitive controllers are designed and implemented within the valid range of the linear approximation. Successive iterations of the identification and control are then performed to drive the system output towards the desired output trajectory