Oxford Biosignals Limited

Rolls-Royce Corporation

Dennis M King

Lionel Tarassenko

Paul Robert Hayton

Paul Anuzis

Stephen Peter King

David Andrew Clifton

Kenneth Astley

Paul Michael Hayton

Robert William Slater

Steven P King

David J Ault

Ken Astley

Steve P King

Simukai Utete

Vibration amplitudes are recorded as a function of rotation speed and of frequency and the data is analyzed to estimate a noise floor amplitude threshold for each of a plurality of different speed and frequency sub-ranges. On the basis of training data known to be normal speed-frequency areas which contain significant spectral content in normal operation are deemed 'known significant spectral content', so that during monitoring of new data points which correspond to significant vibration energy at speeds and frequencies different from the known significant spectral content can be deemed 'novel significant spectral content' and form the basis for an alert. The estimation of the noise floor is based on a probabilistic analysis of the data in each speed-frequency area and from this analysis an extreme value distribution expressing the probability that any given sample is noise is obtained.

Method and apparatus for monitoring and analyzing vibrations in rotary machines

A method and apparatus for detecting an abnormality in e.g. in operating characteristics or function of a machine, apparatus or system, the method including providing a data sample set comprising n values of a measured physical parameter associated with the apparatus or system generated by repeating a measurement of the physical parameter n times. An extremal measured parameter value is selected from amongst the data sample set, determining a probability of observing the selected parameter value (e.g. of observing a value not exceeding the selected parameter value) by applying the selected parameter value to an extreme value probability distribution function having a location parameter and a scale parameter. The value of the location parameter and the value of the scale parameter are each constructed using an integer value m (e.g. notionally representing the size of a sub-sample data set comprising m of said measured parameter values) in which m is less than n (i.e. m&#x3c;n). A conditional indication is given that the selected parameter value is abnormal according to the value of the probability.

Novelty detection

A method of analysing tachometer and vibration response data from an apparatus having one or more rotary components is provided. The method comprises the steps of: providing vibration response data and corresponding tachometer data from the apparatus for a period over which a rotary component of the apparatus varies in rotational speed, the tachometer data being for that component; repeatedly performing at intervals throughout the period the sub-steps of: determining a forcing frequency of the component from the tachometer data and a corresponding vibration response frequency of the apparatus from the vibration response data, comparing the forcing and vibration response frequencies to determine the relative phase difference between the frequencies, and determining the corresponding amplitude of the vibration response from the vibration response data; and plotting the relative phase differences and vibration amplitudes on a polar diagram. The plot trajectory is characteristic of the behavior of the apparatus over the period.

Method and system for analysing tachometer and vibration data from an apparatus having one or more rotary components

A health monitoring apparatus for a mechanical system includes: a microphone arranged to receive sound from the system; and a processor adapted to process the output of the microphone. The mechanical system may be a gas turbine engine. Further, the engine may have a plurality of bleed valves, each of the bleed valves being configured such that, when open, it produces a sound which is distinguishable from the sounds produced by the other bleed valves, and the microphone being arranged to detect the sound from the bleed valves.

Gas turbine engine with a plurality of bleed valves

Novel tracked orders (i.e., tracked orders that are not present in 'healthy' machinery) are useful for locating bearing anomalies. Accordingly, a method for locating bearing anomalies in machinery is provided that includes receiving vibration measurements acquired from the machinery, analyzing the vibration measurements to identify novel tracked orders indicative of bearing anomalies, and ascertaining the location of a bearing anomaly by relating a novel tracked order thus-identified to one or more further tracked orders. Thus, the novel tracked order does not merely indicate the occurrence of a bearing anomaly, but, in combination with the one or more further tracked orders, allows the bearing anomaly to be traced to a particular position.

Bearing anomaly detection and location

A method for monitoring the health of a system comprises performing at each of a plurality of times the steps of: constructing a condition signature from a plurality of condition indicators including (a) a plurality of vibration measurements acquired from the system or (b) one or more vibration measurements and one or more performance parameter measurements acquired from the system; predicting a normal signature from a model defining one or more inter-dependencies between said condition indicators, the normal signature corresponding to the condition signature for a healthy system; comparing the condition signature with the normal signature; and registering an event if the condition signature differs from the normal signature by more than a predetermined threshold.

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Derby, United Kingdom

Dennis M King