Walter H. Chung

A game theoretic fault detection filter

The fault detection process is approximated with a disturbance attenuation problem. The solution to this problem, for both linear time-varying and time-invariant systems, leads to a game theoretic filter which bounds the transmission of all exogenous signals except the fault to be detected. In the limit, when the disturbance attenuation bound is brought to zero, a complete transmission block is achieved by embedding the nuisance inputs into an unobservable, invariant subspace. Since this is the same invariant subspace structure seen in some types of detection filters, we can claim that the asymptotic game filter is itself a detection filter. One can also make use of this subspace structure to reduce the order of the limiting game theoretic filter by factoring this invariant subspace out of the state space. The resulting lower dimensional filter will then be sensitive only to the failure to be detected. A pair of examples given at the end of the paper demonstrate the effectiveness of the filter for time-invariant and time-varying problems in both full-order and reduced-order forms.

Fault detection via parameter robust estimation

We derive and analyze a fault detection filter which is robust to model uncertainty. To do this, we recast the fault detection problem as a disturbance attenuation problem and then incorporate parameter variations as an additional disturbance. The corresponding solution is a parameter robust game theoretic fault detection filter. A second look at our results, however, shows that the parameter robust estimation problem is equivalent to the measurement feedback H/sup /spl infin// control problem and that the parameter robust filter cannot converge asymptotically to a classic detection filter structure.

A Game Theoretic Filter for Fault Detection and Isolation

Abstract The fault detection process is modelled as a disturbance attenuation problem. The solution to this problem leads to an H∞ filter which bounds the transmission of all exogenous signals save the fault to be detected. It is shown that this tranmission bound can be taken to zero, making the game filter into a fault detection filter. When specialized to time-invariant systems, the limiting filter is equivalent the well-known Beard-Jones Fault Detection Filter.