A delay-dependent dual-rate PID controller over an ethernet network

Abstract—In this paper, a methodology to design controllers able to cope with different load conditions on an Ethernet network is introduced. Load conditions induce time-varying delays between measurements and control. To face these variations an interpo-lated, delay-dependent gain scheduling law is used. The lack of synchronization is solved by adopting an event-based control ap-proach. The dual-rate control action computation is carried out at a remote controller, whereas control actions and measurements are taken out locally at the controlled process site. Stability is proved in terms of probabilistic linear matrix inequalities. TrueTime simula-tions in an Ethernet case show the benefit of the proposal, which is later validated on an experimental test-bed Ethernet environment. Index Terms—Multirate control systems, network delay, net-worked control system, PID controller, stability analysis. I