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Fault Detection in Single Stage Helical Planetary Gearbox Using Artificial Neural Networks (ANN) and Decision Tree with Histogram Features

BSACIST-Syed Shaul Hameed, Muralidharan Vaithiyanathan, Mahendran Kesavan
  • Technical Paper
  • 2019-28-0151
To be published on 2019-10-11 by SAE International in United States
Drive train failures are most common in wind turbines. Lots of effort has been made to improve the reliability of the gearbox but the truth is that these efforts do not provide a lifetime solution. Majority of failures are caused by bearing and gearbox. It also states that wind turbine gearbox failure causes the highest downtime as the repair has to be done at Original Equipment Manufacturer [OEM]. This work aims to predict the failures in planetary gearbox using fault diagnosis technique and machine learning algorithms. In the proposed method the failing parts of the planetary gearbox are monitored with the help of accelerometer sensor mounted on the planetary gearbox casing which will record the vibrations. A prototype has been fabricated as a miniature of single stage planetary gearbox. The vibrations of the healthy gearbox, sun defect, planet defect and ring defect under loaded conditions are obtained. The signals show the performance characteristics of the gearbox condition. These characteristics and their number of occurrences were plotted in a histogram graph. Predominant statistical features which represent…
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The Right Stuff for Aging Electronics/Intermittence/No Fault Found

Universal Synaptics-Hector I. Knudsen
Published 2019-09-16 by SAE International in United States
For those in the avionics repair and maintenance business, the acronyms NFF (No Fault Found), NTF (No Trouble Found), and CND (Cannot Duplicate) are, unfortunately, all too familiar terms. After several decades of frustration with this illusive phenomenon, it continues to consume an enormous amount of test and diagnostic effort and is the source of considerable cost and discomfort within the multi-level avionics repair model.There are undoubtedly many causes of NFF and all of them should be addressed. The question is: Where do you start and which solution will be the most beneficial?Our particular efforts have focused on the literal or statistical analysis of NFF, recognizing that if the system’s MTBF (Mean Time Between Failure) has decreased, or if the device's NFF rate has increased with age and deterioration, a physical fault is most likely present. However, if it isn’t found during conventional testing then it probably only fails intermittently. Similarly, having an intermittent failure mode, it in all probability cannot be detected or diagnosed at testing time because of known and demonstrated limitations in…
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Safety Analysis: The Key to a Single-Pass ISO26262 Random Fault Workflow

  • Magazine Article
  • TBMG-34629
Published 2019-06-01 by Tech Briefs Media Group in United States

Advanced driver-assistance systems and autonomous drive technologies increase the complexity of automotive integrated circuits (ICs), making it harder to ensure that ICs are protected from random hardware faults. Safety mechanisms must be inserted to identify and control these unpredictable functional failures, and ISO26262 requires that the effectiveness of every safety mechanism is proven.

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Keyword Protocol 1281

Vehicle E E System Diagnostic Standards Committee
  • Ground Vehicle Standard
  • J2818_201905
  • Current
Published 2019-05-20 by SAE International in United States
This Technical Information Report defines the diagnostic communication protocol Keyword Protocol 1281 (KWP1281). This document should be used in conjunction with SAE J2534-2 in order to fully implement the communication protocol in an SAE J2534 interface. Some Volkswagen of America and Audi of America vehicles are equipped with ECUs, in which a KWP1281 proprietary diagnostic communication protocol is implemented. The purpose of this document is to specify the KWP1281 protocol in enough detail to support the requirements necessary to implement the communication protocol in an SAE J2534 interface device.
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A Fault Tolerant Time Interval Process for Functional Safety Development

Ford Motor Co., Ltd.-Daniel Denomme, Sam Hooson
kVA-James Winkelman
Published 2019-04-02 by SAE International in United States
During development of complex automotive technologies, a significant engineering effort is often dedicated to ensuring the safe performance of these systems. An important aspect to consider when assessing the viability of different safety designs or strategies is the time period from the occurrence of a fault to the violation of a Safety Goal (SG). This time period is commonly referred to as the Fault Tolerant Time Interval (FTTI). In Automotive Safety, ISO 26262 [1] calls for the identification and appropriate partitioning of the FTTI, however very little guidance is provided on how to do this. This paper presents a process, covering the entire safety development lifecycle, for the identification of timing constraints and the development of associated requirements necessary to prevent Safety Goal violations.
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Regression Techniques for Parameter Estimation of a Synchronous Machine from Sudden Short-Circuit Testing

P.C. Krause And Associates Inc.-Brett A. Robbins, Will Perdikakis
US Air Force-Kevin J. Yost
Published 2019-03-19 by SAE International in United States
A sudden short-circuit (SSC) laboratory test of an electric machine is a commonly used procedure to estimate model parameters that accurately represent the dynamic response of the machine. While the graphical interpretation of the short-circuit current is often discussed in great detail, the numerical methods used to determine the solution for the machine parameter estimation is a challenging proposition. In this paper, the authors present an integral regression technique to fit the characteristic equation of the short-circuit current to a curve that is composed of exponential decays that trail off to an unknown steady-state value in the presence of noise. The proposed estimation method is applied to laboratory data from an aerospace synchronous machine.
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Self-Stabilizing, Distributed, Symmetric, Fault-Tolerant Synchronization

  • Magazine Article
  • TBMG-33923
Published 2019-03-01 by Tech Briefs Media Group in United States

Distributed systems have become an integral part of safety-critical computing applications, necessitating system designs that incorporate complex fault-tolerant resource management functions to provide globally coordinated operations with ultra-reliability. As a result, robust clock synchronization has become a required fundamental component of fault-tolerant, safety-critical distributed systems. Since physical oscillators are inherently imperfect, local clocks of nodes of a distributed system, driven by these oscillators, do not keep perfect time and can drift with respect to real time and one another. Thus, the local clocks of the nodes must periodically be re-synchronized. As a result, a fault-tolerant system needs a clock synchronization algorithm that tolerates imprecise local clocks and faulty behavior by some processes.

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Management of RAM Fault for Safety Applications

John Deere-Anavaratha Selvan Ganapathi
Published 2019-01-09 by SAE International in United States
As safety compliance (ISO 26262) has become a norm for automotive embedded software development, the OEMs and Tier1 are pushed to follow the safety guidelines during hardware, software development process. This demands the microcontroller to not only detect internal faults but also find the exact root cause of the failure and have a self-healing mechanism. This paper presents proposed fault detection, injection, testing and shows comparison of microcontroller fault handling with respect to ISO26262 safety standard between proposed method and traditional method by giving the example of RAM test. Also gives an overview of software implementation of this concept as per AUTOSAR standard.
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DC Arc Fault Detection Methods in MEA Distribution Systems

University of Strathclyde-Jeffy Thomas, Rory Telford, Puran Rakhra, Patrick Norman, Graeme Burt
Published 2018-10-30 by SAE International in United States
Direct current (DC) for primary power distribution is a promising solution that is being explored by aircraft system integrators for MEA applications to enable the paralleling of non-synchronized engine off-take generators, and to enable the reduction of energy conversion stages required to supply electronically actuated loads. However, a significant challenge in the use of DC systems is the reliable detection of arc faults. Arcing presents a significant fire risk to aircraft and their presence can result in critical system damage and potentially fatal conditions. Series arc faults in DC systems are particularly challenging to detect as the associated reduction in system current eliminates the use of conventional overcurrent and current differential methods for fault detection. This paper provides an overview of series arc faults in DC systems and presents both simulation and hardware results to illustrate key trends, characteristics and discriminating features. It also presents a comprehensive review of arc fault detection and diagnosis techniques that have been proposed for a wide range of aerospace and other applications. The paper concludes with a discussion on…
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Guidelines for Time-Limited-Dispatch (TLD) Analysis for Electronic Engine Control Systems

E-36 Electronic Engine Controls Committee
  • Aerospace Standard
  • ARP5107C
  • Current
Published 2018-09-04 by SAE International in United States
This SAE Aerospace Recommended Practice (ARP) provides methodologies and approaches which have been used for conducting and documenting the analyses associated with the application of Time Limited Dispatch (TLD) to the thrust control reliability of Full Authority Digital Engine Control (FADEC) systems. The TLD concept is one wherein a fault-tolerant system is allowed to operate for a predetermined length of time with faults present in the redundant elements of the system, before repairs are required. This document includes the background of the development of TLD, the structure of TLD that was developed and implemented on present generation commercial transports, and the analysis methods used to validate the application of TLD on present day FADEC equipped aircraft. Although this document is specific to TLD analyses (for FADEC systems) of the loss of thrust control, the techniques and processes discussed in this document are considered applicable to other FADEC system failure effects or other systems, such as: thrust reverser, and propeller control systems, and overspeed protection systems.
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