In this paper, we deal with large-scaled control systems, in particular, hierarchically distributed structure of the control systems. Our main purpose is clarify the trade-off and the role-sharing of the individual controllers, the upper level global controller and the lower level local controllers. Our idea for this purpose is to introduce a reference model, which represents an aggregated system composed of the local subsystems. Each locally controlled subsystem is designed to satisfy both of the local control performance and the model matching to the reference model. On the other hand, the global controller is designed to satisfy both of the global control performance and the compensation for the model matching errors in the local subsystems. Then we clarify the trade-off by using these quantities from the viewpoint of robust control. Furthermore, we introduce a stochastic property on the model matching errors and discuss the trade-off in a probabilistic sense.
View full abstract