Extension of the parity-space method to fault diagnosis of bilinear systems

Abstract

In this paper, the parity-space method for linear fault diagnosis is extended to bilinear systems. By including bilinear terms into the system matrix, a linear time-varying model with known time-varying feature is obtained. The parity-space method can then be applied to generate residuals in each sampling interval. A recursive algorithm is developed for calculating the matrices in the parity equation, so that the computing time is greatly reduced. Fault isolation is achieved at the residual stage using one parity check instead looking at a bank of parity equations. Component, actuator and sensor faults are isolated by applying an elementary transformation and the singular value decomposition techniques. A numerical example is used to demonstrate the effectiveness of the method.