Multimodel Fault Detection Using Constrained Kalman Filtering

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Solution Overview

Problem

Existing fault detection methods in industrial systems often lead to false failures due to operational changes and lack of robustness in handling modeling errors and measurement noise, particularly in petrochemical industries where reliability and safety are critical.

Innovation Solution

A multimodel fault detection and diagnosis system utilizing a constrained Kalman filter (CKF) supervisor that generates a bank of submodels for both healthy and faulty scenarios, allowing for the use of analytical, data-driven, or combined models, and effectively handles modeling errors and noise by projecting estimates onto constraint spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single reference model is used for fault detection, then the detection method is simple, but false failures are detected due to operational changes and natural moves between operating regions

Engineering Contradiction:
Improvedetection method complexityVSAvoidfault detection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system segments the operational space into multiple operating regions, each with its own reference model. This segmentation allows the system to adapt to natural transitions between operating conditions without triggering false alarms, while maintaining simple detection logic within each region.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between different reference models based on the current operating region. This dynamic adaptation enables the fault detection system to follow natural operational changes while maintaining reliability, avoiding the static limitations of a single reference model.

Inventive Principle:
Principle #15Dynamics

2Reliability

If multiple models are used to cover different operating regimes, then fault detection reliability is improved, but device complexity increases

Engineering Contradiction:
Improvefault detection reliabilityVSAvoidmodel bank complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The operational space is segmented into distinct regions, each governed by a simple reference model. This segmentation reduces the complexity of individual models while maintaining overall reliability through comprehensive coverage of all operating conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system employs a universal framework that can accommodate multiple reference models within a single fault detection architecture. This multi-functional approach allows different models to work together harmoniously, improving reliability without proportionally increasing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If operational data is processed through constrained Kalman filter with model bank, then measurement noise and modeling errors are handled effectively, but computational complexity increases

Engineering Contradiction:
Improvenoise and error handlingVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system applies partial filtering through the constrained Kalman filter, focusing computational resources on the most critical aspects of noise and error handling. This selective approach provides sufficient robustness without the full computational burden of exhaustive filtering.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The constrained Kalman filter acts as an intermediary between the multiple reference models and the fault detection logic. This mediator handles the computational complexity of noise and error management, allowing the individual models to remain relatively simple while achieving robust overall performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS11435734B2Apparatus and method for failure detection
Publication Date: 2022.09.06 YOKOGAWA SAUDI ARABIA
  • US11435734B2 patent drawing
  • US11435734B2 patent drawing
  • US11435734B2 patent drawing

AI summary

In a method for failure, detection, operational data from a plurality of components in a system are received. A bank of submodels is created based on the operational data. The bank of submodels corresponds to a normal mode and one or more faulty modes of the system and is valid in different operating regimes of the system. Each of the banks of submodels has a respective weight (validity) and a respective suboutput. An output of the system is a weighted sum of the suboutputs of the submodels. The operational data is therefore processed to generate a validity profile through a constrained Kalman Filter (KCF) based multimodel fault detection and diagnosis (FDD). Subsequently, the validity profile is output. The validity profile is indicative of an operation state of the system at a given time, and the operation state includes a normal state and a fault state.