Integrated In-Flight Fault Detection and Accommodation: A Model-Based Study

2005 ◽  
Author(s):  
Randal T. Rausch ◽  
Kai F. Goebel ◽  
Neil H. Eklund ◽  
Brent J. Brunell
Keyword(s):  
High Fidelity Simulation ◽  
Turbofan Engine ◽  
Multiple Faults ◽  
Safety Critical ◽  
Fault Accommodation ◽  
Model Based ◽  
Flight Envelope ◽  
Binary Classifiers ◽  
Millisecond Range ◽  
Integrated Detection

In-flight fault accommodation of safety-critical faults requires rapid detection and remediation. Indeed, for a class of safety critical faults, detection within a millisecond range is imperative to allow accommodation in time to avert undesired engine behavior. We address these issues with an integrated detection and accommodation scheme. This scheme comprises model-based detection, a bank of binary classifiers, and an accommodation module. The latter biases control signals with pre-defined adjustments to regain operability while staying within established safety limits. The adjustments were developed using evolutionary algorithms to identify optimal biases off-line for multiple faults and points within the flight envelope. These biases are interpolated online for the current flight conditions. High-fidelity simulation results are presented showing accommodation applied to a high-pressure turbine fault on a commercial, high-bypass, twin-spool, turbofan engine throughout the flight envelope.

Integrated in-Flight Fault Detection and Accommodation: A Model-Based Study

2007 ◽  
Vol 129 (4) ◽  
pp. 962-969 ◽  
Author(s):  
Randal T. Rausch ◽  
Kai F. Goebel ◽  
Neil H. Eklund ◽  
Brent J. Brunell
Keyword(s):  
High Fidelity Simulation ◽  
Multiple Faults ◽  
Safety Critical ◽  
Fault Accommodation ◽  
Model Based ◽  
High Pressure Compressor ◽  
Flight Envelope ◽  
Binary Classifiers ◽  
Millisecond Range ◽  
Integrated Detection

In-flight fault accommodation of safety-critical faults requires rapid detection and remediation. Indeed, for a class of safety-critical faults, detection within a millisecond range is imperative to allow accommodation in time to avert undesired engine behavior. We address these issues with an integrated detection and accommodation scheme. This scheme comprises model-based detection, a bank of binary classifiers, and an accommodation module. The latter biases control signals with pre-defined adjustments to regain operability while staying within established safety limits. The adjustments were developed using evolutionary algorithms to identify optimal biases off-line for multiple faults and points within the flight envelope. These biases are interpolated online for the current flight conditions. High-fidelity simulation results are presented showing accommodation applied to a high-pressure compressor fault on a commercial, high-bypass, twin-spool, turbofan engine throughout the flight envelope.

Modelling, Analysis and Flight Testing of a Military Turbofan Engine Under Windmilling Conditions

2019 ◽  
Author(s):  
Budharaju Balaji ◽  
N. Om Prakash Raj ◽  
Mahesh P. Padwale ◽  
G. P. Ravishankar
Keyword(s):  
Present Model ◽  
Operating Conditions ◽  
Time Dependent ◽  
Flight Testing ◽  
Flight Tests ◽  
Turbofan Engine ◽  
Safety Critical ◽  
Proposed Model ◽  
Modelling Analysis ◽  
Flight Envelope

Abstract Flight testing of a military low bypass turbofan engine involves multitudes of tests to ensure the Engine - Aircraft compatibility across the flight envelope. One of the safety critical tests is to conduct In-Flight restart of the engine. Detailed planning and careful execution is mandated for a single engine aircraft. Accurate modelling of sub-idle performance characteristics of the engine during windmilling conditions enables better prediction of engine behavior during in-Flight shutdown and restart. Typically, Engine manufacturer provides a Performance Cycle Deck (PCD) to predict and assess the performance of the engine across the flight envelope for all throttle positions. However, the PCD does not include sub-idle behavior. The present work focusses on developing a torque based engine behavior model which enables prediction of time dependent fan and compressor characteristics during sub-idle operations. The proposed model is divided into two parts. The first part deals with deceleration characteristics during engine shut-off and spool down, and the second part deals with the acceleration characteristics during spooling up and engine restart. In-flight spool-down (a quick relight without windmilling) restart data obtained through flight tests was used to validate the present model. The model is intended to be used for future flight tests which include windmill restarts under various operating conditions. The model is expected to accurately predict the correlation between aircraft speed and engine windmilling rotor speeds for arriving at a windmill restart envelope for the aircraft.

A hybrid hidden Markov model towards fault detection of rotating components

2016 ◽  
Vol 23 (19) ◽  
pp. 3175-3195 ◽  
Author(s):  
Ayan Sadhu ◽  
Guru Prakash ◽  
Sriram Narasimhan
Keyword(s):  
Fault Detection ◽  
Markov Model ◽  
Hidden Markov Model ◽  
Time Scale ◽  
Hidden Markov ◽  
Energy Operator ◽  
Fault Classification ◽  
Multiple Faults ◽  
Condition Indicators ◽  
Model Based

A robust hybrid hidden Markov model-based fault detection method is proposed to perform multi-state fault classification of rotating components. The approach presented in this paper enhances the performance of the standard hidden Markov model (HMM) for fault detection by performing a series of pre-processing steps. First, the de-noised time-scale signatures are extracted using wavelet packet decomposition of the vibration data. Subsequently, the Teager Kaiser energy operator is employed to demodulate the time-scale components of the raw vibration signatures, following which the condition indicators are calculated. Out of several possible condition indicators, only relevant features are selected using a decision tree. This pre-processing improves the sensitivity of condition indicators under multiple faults. A Gaussian mixing model-based hidden Markov model (HMM) is then employed for fault detection. The proposed hybrid HMM is an improvement over traditional HMM in that it achieves better separation of the feature space leading to more robust state estimation under multiple fault states and measurement noise scenarios. A simulation employing modulated signals and two experimental validation studies are presented to demonstrate the performance of the proposed method.

Model-based assurance evidence management for safety–critical systems

2022 ◽  
Author(s):  
Jose Luis de la Vara ◽  
Arturo S. García ◽  
Jorge Valero ◽  
Clara Ayora
Keyword(s):  
Critical Systems ◽  
Safety Critical ◽  
Model Based ◽  
Safety Critical Systems

scholarly journals A New Approach to Multiple Fault Diagnosis: A Combination of Diagnostic Matrices, Graphs, Algebraic and Rule-Based Models. The Case of Two-Layer Models

2008 ◽  
Vol 18 (4) ◽  
pp. 465-476 ◽  
Author(s):  
Antoni Ligęza ◽  
Jan Kościelny
Keyword(s):  
Fault Diagnosis ◽  
Simultaneous Occurrence ◽  
Diagnostic Model ◽  
Rule Based ◽  
New Approach ◽  
Multiple Fault ◽  
Multiple Faults ◽  
Model Based ◽  
Multiple Fault Diagnosis ◽  
System Variables

A New Approach to Multiple Fault Diagnosis: A Combination of Diagnostic Matrices, Graphs, Algebraic and Rule-Based Models. The Case of Two-Layer ModelsThe diagnosis of multiple faults is significantly more difficult than singular fault diagnosis. However, in realistic industrial systems the possibility of simultaneous occurrence of multiple faults must be taken into account. This paper investigates some of the limitations of the diagnostic model based on the simple binary diagnostic matrix in the case of multiple faults. Several possible interpretations of the diagnostic matrix with rule-based systems are provided and analyzed. A proposal of an extension of the basic, single-level model based on diagnostic matrices to a two-level one, founded on causal analysis and incorporating an OR and an AND matrix is put forward. An approach to the diagnosis of multiple faults based on inconsistency analysis is outlined, and a refinement procedure using a qualitative model of dependencies among system variables is sketched out.

Model-Based Analysis for Safety Critical Software

2015 ◽  
pp. 111-120 ◽  
Author(s):  
Stefan Gulan ◽  
Jens Harnisch ◽  
Sven Johr ◽  
Roberto Kretschmer ◽  
Stefan Rieger ◽  
...  
Keyword(s):  
Safety Critical ◽  
Model Based ◽  
Model Based Analysis
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