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Autonomous Methods for Condition-based Maintenance of Rotating Machinery

Condition-based maintenance (CBM) is a maintenance strategy where maintenance decisions are made based on the actual health of the monitored system. In CBM, the health of the monitored system is typically inferred through some surrogate measure of degradation (i.e. vibration or temperature). It consists of three main steps: data acquisition, data processing and maintenance decision-making. Diagnostics and prognostics are two important aspects of a CBM Methodology (see Figure 1).

CBM Steps
Figure 1: Key Steps in CBM

We are currently we are investigating critical airport infrastructure under the CBM framework, namely the LINK Train automated people mover (APM) system and baggage handling systems (BHS) located in Toronto’s Pearson International Airport, Canada, which is managed and operated by the Greater Toronto Airports Authority (GTAA). The main goals of this project include:

  • Development of blind algorithms for performing fault detection on non-stationary rotating machinery, that are suitable for implementation in autonomous or semi-autonomous CBM frameworks. The primary focus here is to develop new vibration analysis methods that scalable and robust, by removing the dependency on prior knowledge found in many contemporary vibration analysis techniques. Key methods include cluster-based approaches using mean shift clustering and Gaussian mixture models in conjunction with statistical process control methods for threshold setting and fault detection.
  • Development of novel degradation models which can be used to estimate the remaining lifetime of the system. Key methods being pursued in prognosis are data-driven methods such as hidden Markov models (HMMs) and Bayesian inference techniques.
  • Software and hardware development for integrated, autonomous fault detection and prognosis CBM framework
  • Fig2
    Figure 2: CBM implementation at Toronto's Pearson Airport’s LINK Train APM gearbox illustrating the accelerometers and real-time monitoring hardware (NI cRIO)

    Fig3
    Figure 3: Components of autonomous CBM platform – client and server tasks

    Fig4a
    Fig4b
    Figure 4: APM vibration data and corresponding spectrogram illustrating non-stationarities in both time and frequency

    Fig5
    Figure 5: Blind clustering of condition indicators extracted from APM vibration data using Gaussian mixture method. Non-stationary data is decomposed into discrete stationary clusters that can be used for binary fault detection.

    Fig6
    Figure 6: Hierarchical Bayesian degradation model for (a) 40 and (b) 60 percent of degradation signal

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