Fault detection and diagnosis for three-tank system using robust residual generator

A Asokan

doi:10.17485/ijst/2009/v2i7.2

Abstract

Fault detection and diagnosis (FDD) is a task to deduce from observed variable of the system if any component is faulty, to locate the faults and also to estimate the fault magnitude present in the system. The main goal when synthesizing robust residual generators, for diagnosis and supervision, is to attenuate influence from model uncertainty on the residuals while keeping fault detection performance. In this paper, a design procedure for robust residual generators is developed with two key elements. One is the use of a reference model that represents desired performance. The other is an optimization criterion, based on robust H ∞ filtering, used to synthesize the residual generator.

Highlights

Faults main goal when synthesizing robust residual generators, for diagnosis and supervision, is to attenuate influence from model uncertainty on the residuals while keeping fault detection performance
Output procedure for robust residual generators is developed with two key elements
Different approaches for fault detection using mathematical models have been developed in the Robust fault detection scheme

Summary

Problem formulation

With uncertain models it is in most cases Since available models of real processes always are impossible to get the first term = 0 for all ∆ i.e. for all uncertain, there is naturally a need for robust methods possible instances of uncertainties, without loosing some minimizing the sensitivity to the model uncertainties This or all of the desired fault sensitivity. Focus is on to find the filter Q(s) such that a proper trade off between designing robust residual generators, dealing with model fault sensitivity and robustness towards model uncertainty uncertainty, to fit in a structured residuals framework. It is necessary that the reference model, R(s), contains the necessary structure for Q(s) to be a residual generator This includes decoupling properties of faults, i.e. zeros at proper positions in R(s) corresponding to the desired residual structure

Robust residual generator synthesis

Robustness criterion

System descriptions

Design of structured residual generator

Simulation results