On residual generation by observer and parity space approaches

A unifying framework for observer design by eigenstructure assignment is described. A novel technique for structured residual generation based on this framework is proposed. One of the main features of this technique is that the equivalence between residual generation by means of observers and parity space devices is made conspicuous. More precisely, from a computational point of view, the equations to solve in both cases are shown to be similar. For implementation, both devices are shown to be identical. A necessary and sufficient condition for the existence of structured residuals is given. The sensitivity of structured residuals to nondecoupled failures is studied, and a procedure for maximizing this sensitivity is described