Further analysis on network-induced time-varying delay modeling methods used in GPC design

The networked control systems (NCSs) have nowadays applications ranging from factory and home automation, to automotive and avionic control systems and to military and spatial applications. Their widely inclusion in the industry was mainly due to the inherent advantages, e.g. lower costs, simpler installation and maintenance, higher reliability and greater flexibility. Although the subject was extensively studied during the last decades, the effect of introducing a communicatio network in the closed-loop control system needs to be more carefully studied. The main disadvantage is considered to be the network-induced time-varying delay which can degrade the control systems performances and can even lead to the instability of the networked control system. This paper studies and analyses the effect of different modeling methods for the network-induced time-varying delays on the networked control systems performances. The modeling methods are used in the design phase of a generalized predictive control (GPC) strategy and the performance evaluation is performed on a typical networked application, i.e., direct current (DC) motor controlled through an Ethernet network.