Exact fault and disturbance decoupling by means of direct input reconstruction and estimation of the inverse dynamics

The idea of inversion-based direct input reconstruction for robust detection and separation of multiple, possibly simultaneous faults in the presence of external, non-mutually separable disturbances for linear dynamical systems was presented in [1]. In this short paper this concept is pursued further: it is shown how in a specific filtering structure, relying on the inverse representation of the system, a Luenberger state observer can be designed providing estimation of the states of the inverse-based residual generator reverting to disturbance decoupled detection residuals with exact fault separation. This result can be considered as a corollary of the approximate disturbance attenuating solution presented in [1].