Estimating and controlling loading experienced in a structure

A system for controlling an amount of undesired loading experienced by at least a component of a structure, the system comprising:

• a load estimator configured to estimate the amount of undesired loading experienced by the at least the component of the structure based at least partially on an estimate of the amount of undesired loading experienced by the component of the structure;
• and
• a controller configured to control the amount of undesired loading experienced by the at least the component of the structure based at least partially on the estimated amount of undesired loading experienced by the at least the component of the structure,
• wherein the load estimator comprises:
• a first filter module configured to produce a first filtered signal by filtering out one or more frequencies of a first signal, the first signal characterizing instantaneous stress experienced by the component of the structure, and the one or more filtered out frequencies including frequencies corresponding to the desired loading experienced by the component;
• and
• a first signal processing unit configured to process the first filtered signal to produce the estimate of the amount of undesired loading experienced by the component, wherein the first signal processing unit estimates the amount of undesired loading experienced by the component by one of:
• calculating a standard deviation of the first filtered signal;
• calculating one or more spectral moments of the first filtered signal, wherein the one or more spectral moments of the first filtered signal includes the Nth spectral moment, where N is the Wöhler coefficient corresponding to a material out of which the component is made;
• detecting a value of an envelope of the first filtered signal;
• and
• calculating an online rain-flow cycle count of the first filtered signal, and
• wherein the controller adjusts operation of the structure based on the estimate of the amount of undesired loading experienced by the component.

A method for use with a structure comprising a component, the method comprising:

• receiving a signal characterizing instantaneous stress experienced by the component of the structure;
• filtering, using a computer processor, frequencies from the received signal to produce a filtered signal in which at least frequencies that correspond to desired loading experienced by the component are removed;
• detecting, using a detector having a rise time and a decay time that is longer than the rise time, a value of an envelope of the filtered signal to produce an estimate of the amount of loading experienced by the component of the structure;
• and
• operating the structure based on the estimated amount of loading.