A review of observer approaches for fault diagnosis based on bi-linear systems

Observer approaches for fault diagnosis are reviewed with particular emphasis on bilinear systems. An introduction and an overview are given where the basic methods for linear and nonlinear systems are summarised. Several methods of robust residual generation for bilinear systems are then given, including the bilinear fault detection observer method, the full-order bilinear observer method and the minimal-order bilinear observer method. Robust issues are addressed throughout the paper. Hybrid methods, fault isolation and a bilinear parity-space method are briefly discussed