PD-type open-closed-loop iterative learning control in the networked control system

In this work, a PD-type open-closed-loop iterative learning control (ILC) method for networked control systems (NCS) is proposed. Inspired by the hierarchical structure of NCS, the remote open-loop and local closed-loop control structure is proposed to deal with the communication delay and data dropout in NCS. The P-type ILC is applied to closed-loop control and the D-typed ILC is applied to open-loop control. In this way, only the D-typed ILC's offline input and output data are transmitted over the network, thus, the side effects caused by communication delay and data dropout in NCS can be greatly reduced. The criterion of convergence for the proposed method is derived based on 2-D method. Simulation and experiment results have verified the feasibility and effectiveness of the proposed method.