In this paper, robust H∞ control problems for networked control systems (NCSs) with network-induced time delays and subject to norm-bounded parameter uncertainties are presented and solved. Based on a new discrete-time model, two approaches of robust controller design are proposed—design of a memoryless state-feedback controller and design of a dynamic state-feedback controller. The proposed memoryless state-feedback controller design method is given in terms of linear matrix inequalities (LMIs), and the delay bound can be computed by using the standard LMI techniques. A numerical example is given to illustrate the feasibility and effectiveness of this methodology. The proposed dynamic state-feedback controller design method is based on a discrete-time Artstein transform. With the sufficient conditions for robust stability and H∞ control developed in this paper, we also derive the upper bound of network-induced time delays and the lower bound of the network date-transmission rate that can be used as a guideline in choosing proper networks as communication media for NCSs. We constructed an NCS test bed to experimentally verify the feasibility and effectiveness of proposed design methodologies.
Robust State Feedback Controller Design Method Guaranteeing Deterministic H∞ Performance and Stochastic Stability
