Virtual RPM sensor
AssigneeExxonMobil Research and Engineering Company
InventorLimin Song
Life of this patent
Estimating the term…
Abstract
The present invention is in a “virtual RPM sensor” which is preferably implemented by means of a software process. The software determines the RPM of a rotating machine using an adaptive signal processing algorithm. Preferably, the input to the software system of the present invention is digitized waveform data from either a vibration transducer on a rotating machine or vibration data stored in a database or file. The present invention permits the determination of the RPM of a rotating machine without the requirement of additional hardware so that readings may be obtained inexpensively, accurately and without interrupting machine operation.
Claims13
A method for estimating the operating speed of a machine from time-based vibration data samples obtained from a vibration transducer, comprising the steps of:
- (a) acquiring said time-based vibration data samples from said vibration transducer in physical constant with said machine;
- (b) filtering said acquired time-based vibration data samples in order to obtain maximum low order vibration components while eliminating other components;
- (c) estimating machine operating speed using said filtered time-based vibration data samples;
- (d) fine tuning said machine operating speed estimate using a continuous vibration model;
- and
- (e) providing said fine tuned machine operating speed estimate to a user.
A method for estimating the operating speed of a machine from time-based vibration data samples obtained from a vibration transducer, comprising:
- (a) acquiring said time-based vibration data samples from said vibration transducer in physical constant with said machine;
- (b) filtering said time-based vibration data samples in order to obtain maximum low order vibration components while eliminating other components;
- (c) estimating machine operating speed using said filtered time-based vibration data samples, wherein said estimating operating machine speed is accomplished through the use of a digital comb filter;
- (d) fine tuning said machine operating speed estimate using a continuous vibration model;
- and
- (e) providing said fine tuned machine operating speed estimate to a user.
A method for estimating the operating speed of a machine from time-based vibration data samples obtained from a vibration transducer, comprising:
- (a) acquiring said time-based vibration data samples from said vibration transducer in physical constant with said machine;
- (b) filtering said time-based vibration data samples in order to obtain maximum low order vibration components while eliminating other components;
- (c) estimating machine operating speed using said filtered time-based vibration data samples;
- (d) fine tuning said machine operating speed estimate using a continuous vibration model;
- and
- (e) providing said fine tuned machine operating speed estimate to a user,
- wherein said fine tuning said machine operating speed further comprises:
- (a) selecting a machine speed step length for searching RPM;
- (b) selecting a search range of machine speed based oh the result of an optimal P obtained through the said estimating step;
- (c) using a continuous vibration model of K's vibration harmonics to represent the coherent vibration, in which each harmonic is a vibration component with a frequency as a multiple of RPM, and the number of harmonics are selected to include all possible vibration components in the filtered vibration samples to be processed;
- (d) using a DFT to obtain the coefficients of said continuous vibration model from the filtered dine-based vibration data samples;
- (e) computing the coherent vibration power from said continuous vibration model;
- (f) computing the error function;
- and
- (g) obtaining a machine operating speed measurement that minimizes the cost function.
Dependencies are inferred from the claim text.