Integrated control and fault diagnosis design: A polynomial approach

A design method is presented which integrates control action and fault detection and isolation. Control systems operating under potentially faulty conditions are considered, and it is demon-strated how to design a single unit which handle both the required control action, as well as identifying faults occuring in actuators and sensors. This unit is able to: (1) follow references and reject disturbances robustly, (2) control the system such that undetected failures do not have disastrous eects, (3) reduce the number of false alarms, and (4) identify which faults have occured. The method uses a type of separation principle which makes the design process very transparent, and a polynomial H1 formulation which makes weight selection straightforward. As a consequence of the separation between control and diagnosis, we shall prove that the controller needs not be detuned in order to get good diagnosis results, in contrast to common beliefs.