Simultaneous H2/H∞ fault detection and control for networked systems with application to forging equipment

This paper investigates the simultaneous fault detection and control (SFDC) problems for a class of discrete-time networked systems with multiple stochastic delays and data missing. Both faults and disturbances are assumed to be in low frequency domain. The communication delays are uniformly modeled by multiple random variables obeying the Bernoulli distributions, which are mutually correlated by a prior Pearson correlation coefficient matrix. Then the closed-loop system is formulated as a special jump linear system. The generalized definitions of the H2 and H∞ indexes for such underlying systems are proposed to measure the detection and control performances, respectively. Then a mixed H2/H∞ SFDC approach is proposed to achieve the desired detection and control objectives. To cope with the H2 performance index in a given frequency range directly, by Parseval lemma and S-procedure, a relaxed condition is presented to reduce the conservatism of the existing results. And the integrated detector/controller is derived in terms of solving a set of linear matrix inequalities (LMIs). The developed method is applied to the large forging equipment drive systems, and simulation results demonstrate the effectiveness of the results.