Nonlinear Model Decomposition for Fault Detection and Isolation System Design

Model-based fault detection and isolation methods relies on residuals that must be robust against uncertainties or unknown inputs while remaining sensitive to the faults. Two approaches may be applied to design a residual generator (RG): the first one uses the global model of the system and consider the robustness/sensitivity constraints in the RG synthesis. The second one relies on two steps: First, a structural decomposition of the global system is performed with respect to robustness/sensitivity criteria. Second, residuals generators are designed based on the subsystems generated by the previous decomposition. This paper deals with the second approach. The structural decomposition presented here is achieved through special mathematical tools, namely the algebra of functions. These tools are presented and the computational aspects are deeply investigated. An application on an academic example is provided to illustrate the methodology