Residual generator design for the FDI of linear multivariable sampled-data dynamic systems

This paper addresses the problem of the detection and isolation of the input and output sensor faults for a linear multivariable sampled-data dynamic system, in the presence of disturbance signals. In particular, this work proposes a polynomial approach for the design of residual generators in order to realise a complete diagnosis scheme when additive faults are present. It is shown that the use of an input- output description for the linear dynamic sampled-data model of the system under investigation allows to compute in a straightforward way the discrete-time residual generators. The residual generator design is performed in order to maximise a suitable fault sensitivity function. Thus, the suggested design approach leads to dynamic filters that achieve both disturbance de-coupling and desired transient properties in terms of a fault to residual reference transfer function. The results obtained in the simulation of the faulty behaviour of a discrete-time turbine jet engine model are finally reported.