Fault detection in pipelines using nonlinear observers

This paper investigates the detection of faults in an hydraulic pipeline for which both laminar and non-laminar flows are present. A fault detection observer is developed for classes of nonlinear models which are structured in continuous state space form. The observer is designed such that the error dynamics are independent of state, input, output and unknown disturbances. The conditions for the observer to exist, and remain robust with respect to unknown inputs, are derived. The approach is applied to a particular pipeline to detect simulated faults. The results presented demonstrate the effectiveness of the nonlinear observer for fault detection.