DECENTRALIZED ROBUST CONTROL OF SYSTEMS INTERCONNECTED OVER NETWORKS

Due to recent technological developments, systems which are interconnected over networks have become very common. Typically, a number of subsystems may be interconnected by means of an existing network. Furthermore, each subsystem may also be connected to a controller through the same network. A typical aspect of such interconnections is the inherent time-delay, which is usually unknown, induced by the network. Moreover, besides the uncertainties in the time-delays, both the strength of the interconnections and the subsystem models may also be uncertain. In this paper, a decentralized robust controller design approach is introduced for such systems. The controller design is based on the local models of the subsystems. However, a frequency-dependent scalar robustness bound is also taken into consideration during the design process. This bound accounts for the interactions between the subsystems, as well as for any uncertainties. The proposed design approach guarantees robust stability of the overall system as long as the uncertainties satisfy certain bounds. An example is also presented to demonstrate the proposed approach.