Active Fault Diagnosis using Moving Horizon Input Design

This article considers the design of an input signal for improving the diagnosability of faults from process measurements. Previous work has focused on open-loop input design. In particular, deterministic methods are available for computing an input that guarantees fault diagnosis within a specified time horizon, whenever such an input exists. Here, two closed-loop approaches are considered that use feedback in order to reduce the length and/or cost of the required input, while maintaining this guarantee. The first method uses an existing open-loop input design method within a receding horizon framework. The second method approximates the first by an explicit feedback law in order to reduce online computations.