Dynamic IQC-based analysis and synthesis of networked control systems

This paper presents a new control design approach for networked control systems under the integral quadratic constraint (IQC) framework. In order to apply the IQC and dissipation theory, the networked control system with network-induced time-varying delays is first transformed to an equivalent linear fractional transformation (LFT) model. As such, dynamic IQCs can be used to capture the input-output behavior of the delay nonlinearities. Then, a novel full-information feedback control law is proposed, which utilizes both plant states and the IQC dynamic states, as well as the network-induced delay amounts, as feedback information. Robust ℓ2 stability analysis of the resulting closed loop is performed via dynamic IQCs. Based on the analysis results, the synthesis conditions for the proposed full-information feedback controller are established in a linear matrix inequality (LMI) form, which can be solved effectively using existing convex optimization algorithms. Finally, a servo motor control system is used to demonstrate the effectiveness of the proposed IQC-based control design scheme.