Patent ID: 7657400
Filing Date: 2010-02-02
Classification: G05B

Abstract:
1. A diagnostics subsystem for performing predictive diagnostics on a machine, the subsystem comprising: a set of sensors providing a set of sensed operating parameters of the machine; a process model to: a comparator to provide a set of comparator outputs, each comparator output corresponding to one of the set of sensed operating parameters and the corresponding estimated operating parameter, wherein each comparator output is based on a difference between the corresponding sensed operating parameter and the corresponding estimated operating parameter; discontinuous signal injection means for generating a set of discontinuous injection signals in response to the set of comparator outputs, and for injecting the set of discontinuous injection signals into the process model to maintain sliding mode operation in the process model wherein a difference between each sensed operating parameter and the corresponding estimated operating parameter tends to zero; and an estimator to analyze the set of discontinuous injection signals to detect a deviation of the inferred parameter from a nominal value, wherein the estimator does not infer a fault when detecting a non-zero value in less than two of the set of discontinuous injection signals, and wherein the estimator infers a fault when detecting a non-zero value in at least two of the set of discontinuous injection signals.