Fault detection and isolation based on Takagi-Sugeno modelling

One of the difficulties to detect and isolate faults in nonlinear systems via observer-based methods is the design of a residual generator. In this work a procedure to approach the fault detection and isolation problem in nonlinear systems is proposed. The result is obtained by deriving several subsystems, each subsystem containing information about specific faults, from the plant under consideration. Takagi-Sugeno modelling is used to design fuzzy observers and generate residuals. The detection and isolation task is solved by evaluating these residuals. The advantage of the proposed approach is that the design condition for the observers is relaxed. Furthermore the potential use of decoupling techniques is reinforced. The design methodology is shown using a laboratory three tank system.