Jet Engine Health Signal Denoising Using Optimally Weighted Recursive Median Filters

Uday, Payuna; Ganguli, Ranjan

doi:10.1115/1.3200907

Cited by 15 publications

(17 citation statements)

References 33 publications

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“…For comparative study of the three-point and seven-point WRM filters, test signals proposed by Uday and Ganguli [6] are also used here. The step signal, ramp signal, and combination signal all contain 200 data points and simulate steady state gas path measurement deltas.…”

Section: Test Signalsmentioning

confidence: 99%

Three- and Seven-Point Optimally Weighted Recursive Median Filters for Gas Turbine Diagnostics

Guruprakash

Ganguli

2011

Journal of Engineering for Gas Turbines and Power

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engine components. Zedda and Singh [3] estimated the performance of the gas turbine through the optimization of an objective function by means of genetic algorithm. From the literature, it can be seen that algorithms based on least-squares, Kaiman filters, and soft computing have been widely used for gas turbine diagnostics. A comparative study between Kaiman filter and neural network method was done in Ref. [4]. Recently, the Bayesian approach to gas turbine diagnostics has been used [5].In this note, a study of the effect of integer weight on threepoint weighted recursive median (WRM) filter and seven-point WRM filter is done. Optimal weights for different health signals are obtained. The three-point filter is useful for engines where data are obtained slowly and the seven-point filter where there are more data available. This note expands the earlier work of Uday and Ganguli [6], which was limited to a WRM filter of length tive. The effect of window length on the optimal weights of WRM filters developed for gas turbine diagnostics is brought out.Measured health signais incorporate significant details about any malfunction in a gas turbine. The attenuation of noise and removal of outliers from these health signals while preserving important features is an important problem in gas turbine diagnostics. The measured health signals are a time series of sensor measurements such as the low rotor speed, high rotor speed, fuel flow, and exhaust gas temperature in a gas turbine. In this article, a comparative study is done by varying the window length of acausal and unsymmetrical weighted recursive median fllters and numerical results for error minimization are obtained. It is found that optimal filters exist, which can be used for engines where data are available slowly (three-point filter) and rapidly (sevenpoint filter). These smoothing filters are proposed as preprocessors of measurement delta signals before subjecting them to fault detection and isolation algorithms.

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Section: Test Signalsmentioning

confidence: 99%

Three- and Seven-Point Optimally Weighted Recursive Median Filters for Gas Turbine Diagnostics

Guruprakash

Ganguli

2011

Journal of Engineering for Gas Turbines and Power

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“…Test signals for faults in jet engines are used to demonstrate the algorithm (Uday and Ganguli 2010). For a new undamaged engine, the measurement delta is zero.…”

Section: Gas Path Measurement Signalsmentioning

confidence: 99%

“…The design space of the weights of WRM filters is multimodal (shows the presence of several local minima) and an exhaustive search of the design space can be used to find the weights (Uday and Ganguli 2010). However, this exhaustive search method is very computationally intensive and there is a need for more efficient algorithms for solving this filter weight optimization problem.…”

Section: Introductionmentioning

confidence: 99%

“…Typically, fingerprint charts are used for fault isolation and these relate the measurement deltas produced to a given change in the engine state. For example, Table 1 presents the fingerprint chart for a 2% deterioration in the efficiency of the engine modules (Uday and Ganguli 2010). Fingerprint charts represent a linearized model evaluated at a selected engine operating point.…”

Section: Introductionmentioning

confidence: 99%

“…A numerical approach for the optimization of recursive median filters was presented in Arce and Paredes (2000). Uday and Ganguli (2010) searched over the low integer space (1, 2 and 3) to find the optimal weights. They found that higher integer weights led to duplication in the filter and the low integer space was sufficient for the given problem.…”

Section: Introductionmentioning

confidence: 99%

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Denoising Signals Used in Gas Turbine Diagnostics with Ant Colony Optimized Weighted Recursive Median Filters

Raikar

Ganguli²

2017

INAE Lett

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Accurate fault detection and isolation requires signal processing of measurement signals which are contaminated with noise. Typically, gas turbine faults are revealed by sharp trend shifts in the signals and these trend shifts should be preserved during signal processing. Linear filters can smooth out the sharp trend shifts while removing noise. However, nonlinear filters such as the weighted recursive median (WRM) filters show good noise reduction while preserving key signal features if their integer weights are determined optimally. We propose the ant colony optimization (ACO) method coupled with local search to calculate the integer weights of WRM filters. It is found that the filter weight optimization problem is mathematically equivalent to the quadratic assignment problem which can be solved by ACO. Optimal parameters for the ACO are found using numerical experiments. The WRM filter is demonstrated for abrupt and gradual faults in gas turbines and is found to yield noise reduction of 52-64% for simulated noisy signals considered in this paper.

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Image Processing Filters for Machine Fault Detection and Isolation

Ganguli

2019

Machine Vision and Navigation

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Jet Engine Health Signal Denoising Using Optimally Weighted Recursive Median Filters

Cited by 15 publications

References 33 publications

Three- and Seven-Point Optimally Weighted Recursive Median Filters for Gas Turbine Diagnostics

Three- and Seven-Point Optimally Weighted Recursive Median Filters for Gas Turbine Diagnostics

Denoising Signals Used in Gas Turbine Diagnostics with Ant Colony Optimized Weighted Recursive Median Filters

Image Processing Filters for Machine Fault Detection and Isolation

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