Robust nonlinear observer-based fault detection for a U-tube steam generator

Based on previously proposed nonlinear unknown input observer-based fault detection schemes for uncertain systems the authors suggest a robust fault detection technique for a U-tube steam generator. One major problem in modelling steam generators is the proper identification of the heat transfer coefficients which in reality are distributed parameters depending on the temperature and pressure conditions inside the steam generator. If no counter measures were taken, those improperly identified model parameters would corrupt the residuals generated by a fault detection observer. The problem of designing fault detection observers which are robust to unknown parameters can be reduced to a system of partial differential equations. The authors propose a general method to calculate approximate solutions for first order partial differential equations based on the computer software Mathematica and apply it in turn to the steam generator problem