Robust fault tolerant control of networked control system ( NCS) with variable sampling period and time delays was studied in
this paper． First，a discrete － time model with parameter uncertainties lying inside a polytypic framework whose vertices were determined
through the Real Jordan form approximation is proposed． Based on the model，an observer was proposed to estimate the fault and guarantee
the convergence speed of fault estimation． Furthermore，the robust active fault tolerant controller based on dynamic output feedback
was designed to guarantee the stability of the closed － loop system． A sufficient condition for the existence of controller to guarantee
the system asymptotically stable is established in terms of linear matrix inequalities ( LMIs) ． When the LMIs have an optimal solution，
explicit expression of the desired optimal H∞ tolerant fault controller can be determined． Finally，numerical simulation is presented to illustrate
the effectiveness of the proposed design techniques．