Fault detection, isolation, and estimation—optimal fault estimation

Abstract

The fault estimation problems formulated and studied in the previous chapter seek a residual signal that satisfies two important requirements: exact decoupling of the residual signal from the disturbance or noise, and the residual signal is an exact estimate of the fault signal. The first objective makes the residual signal completely insensitive to the disturbance or noise, and the second objective guarantees that the residual signal is equal to the fault signal. The solvability conditions for such a constrained fault signal estimation are strong. In Chapter 14, we also considered an almost version where the residual signal is arbitrarily close to the fault signal and is almost completely independent of the disturbance. This weakens the solvability conditions, but still the solvability conditions are very strong.