Rail Vehicle Undercarriage Sensor Self-Test via Gravity Signal

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Solution Overview

Problem

Existing monitoring systems for rail vehicle running gear components face challenges in reliably ensuring the functionality of acceleration sensors, particularly due to the difficulty in testing these sensors without disassembly and the added complexity and cost of redundant systems.

Innovation Solution

The acceleration sensor is designed to generate a signal component corresponding to gravitational acceleration g, which serves as a calibration and test signal, allowing for functional monitoring without additional hardware, by checking if the measurement signal contains this component and suppressing error signals if it does, thus simplifying the monitoring process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If acceleration sensors are tested by disassembly and mounting on a calibrated test bench, then measurement precision and reliability can be verified, but the effort and time required increase significantly

Engineering Contradiction:
Improvesensor functionality verificationVSAvoidtesting effort
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the acceleration sensor continuously output a signal component corresponding to gravitational acceleration g during normal operation. This pre-prepared test signal allows functionality verification to be performed at any time without requiring disassembly or special test equipment, thus resolving the contradiction between reliable verification and time-consuming testing procedures

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The acceleration sensor performs self-testing by utilizing the ever-present gravitational acceleration as its own test signal. The sensor monitors its own output signal to verify functionality, eliminating the need for external test benches or disassembly. This self-service approach maintains high reliability verification while minimizing time and effort requirements

Inventive Principle:
Principle #25Self-service

2Reliability

If redundant acceleration sensors are provided for failure detection, then reliability improves, but device complexity and cost increase

Engineering Contradiction:
Improvefailure detection capabilityVSAvoidsensor system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of using redundant sensors, the patent implements a self-service mechanism where each acceleration sensor monitors its own functionality by continuously checking for the presence of the gravitational acceleration signal component in its output. This eliminates the need for redundant sensors while maintaining failure detection capability, thus resolving the contradiction between reliability and device complexity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent employs feedback by having the evaluation device continuously monitor the output signal of the acceleration sensor and check for the expected gravitational acceleration component. When the signal deviates from expectations, the system generates an error indication. This feedback mechanism provides reliable failure detection using the existing single sensor, avoiding the complexity of redundant sensor systems

Inventive Principle:
Principle #23Feedback

3Reliability

If acceleration sensors are mounted in difficult-to-access installation spaces like bogies, then monitoring coverage improves, but ease of repair and testing deteriorates

Engineering Contradiction:
Improvemonitoring coverageVSAvoidsensor accessibility
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The acceleration sensor performs self-testing by utilizing the ever-present gravitational acceleration as its own test signal. The sensor monitors its own output signal to verify functionality, eliminating the need for disassembly or special test equipment. This self-service approach maintains comprehensive monitoring coverage in difficult-to-access locations while eliminating the need for physical access for testing and repair verification

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system prepares test signals (gravitational acceleration) that are continuously available during normal operation. This preliminary preparation of test signals allows functionality verification to be performed remotely through the evaluation device without requiring physical access to the sensor in difficult-to-access installation spaces like bogies

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables cost-effective and straightforward monitoring of acceleration sensors, reducing the effort and complexity involved in ensuring their functionality, while maintaining reliability and minimizing manufacturing and installation costs.

Implementation Method 1

acceleration sensor (28) which delivers a measurement signal which contains a signal component corresponding to the acceleration due to gravity g or represents a signal corresponding to the acceleration due to gravity g

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP2152561B1Device and method for error monitoring for undercarriage components of rail vehicles
Publication Date: 2011.03.02 KNORR BREMSE SYST FUR SCHIENENFAHRZEUGE GMBH
  • EP2152561B1 patent drawingFigure 1~2
  • EP2152561B1 patent drawingFigure 3~4
  • EP2152561B1 patent drawingFigure 5~6

AI summary

The invention relates to a device (2) for monitoring errors in undercarriage components of rail vehicles, having at least one acceleration sensor (28, 28', 28') which works with an evaluation unit (32). At least one acceleration sensor (28, 28', 28') is arranged on the undercarriage of the rail vehicle in such a manner that its direction of detection (30, 30', 30') has at least one component parallel to the vertical axis (z-direction) of the rail vehicle. The invention proposes that the acceleration sensor (28, 28', 28') is constructed in such a manner that it delivers a measuring signal which contains the signal portion corresponding to a ground acceleration, or represents a signal corresponding to a ground acceleration, and that the evaluation unit (32) has a routine for testing functions of the acceleration sensor (28, 28', 28'), the routine controlling an error signal if the measuring signal delivered by the acceleration sensor (28, 28', 28') contains no signal portion corresponding to a ground acceleration. The routine also suppresses the error signal if this is not the case.