Rail Vehicle Obstacle Detection Using Leaf Spring Force Sensing

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Solution Overview

Problem

Existing obstacle detection systems in rail vehicles cannot provide a precise measurement of collision mass and often result in unnecessary braking due to their binary collision detection, which is inadequate for differentiated obstacle recognition and fails to account for varying collision intensities and vehicle speeds.

Innovation Solution

A device using vertically arranged leaf springs as both a mounting bracket and force sensors, equipped with strain-voltage converters, measures the force-time curve during collisions, allowing for differentiated obstacle detection and integrating the data with an on-board evaluation unit to adjust braking thresholds based on vehicle speed, thereby reducing unintended braking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a binary collision detection system with a fixed threshold is used, then the device complexity is low, but the measurement precision of collision mass is insufficient

Engineering Contradiction:
Improvecollision mass detection precisionVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the mounting bracket structure with the force measurement function into a single integrated system. The spring elements serve dual purposes: mechanically mounting the collision beam and simultaneously measuring collision forces through strain-voltage converters, eliminating the need for separate measurement devices and reducing overall system complexity while achieving precise collision mass detection

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The mounting bracket is designed with multi-functionality, serving both as a structural support element and as a measurement sensor. The spring elements with integrated strain-voltage converters enable the same component to perform mechanical mounting and force measurement tasks, reducing device complexity while improving measurement precision

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

2Adaptability or versatility

If a fixed collision threshold is used for obstacle detection, then the ease of operation is high, but the adaptability to different collision intensities and speeds is poor

Engineering Contradiction:
Improveadaptability to collision intensity and speedVSAvoidoperational simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent implements dynamic threshold adjustment based on real-time vehicle speed measurements. The evaluation unit automatically adapts the collision detection threshold according to the current operating speed, enabling the system to respond appropriately to varying collision intensities at different speeds while maintaining operational simplicity through automated control

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback mechanisms where the evaluation unit continuously monitors collision forces, vehicle speed, and compares them against dynamically adjusted thresholds. This feedback loop enables automatic adaptation to different operating conditions, improving versatility while maintaining ease of operation through automated decision-making

Inventive Principle:
Principle #23Feedback

3Force

If the mounting bracket is made rigid to securely hold the collision beam, then the strength is high, but the ability to measure collision force is lost

Engineering Contradiction:
Improvecollision force measurement capabilityVSAvoidmounting bracket strength
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The patent employs flexible spring elements instead of rigid mounting brackets. These spring elements provide the necessary flexibility to deform under collision forces, enabling force measurement through strain-voltage converters, while still maintaining sufficient strength to securely hold the collision beam and transmit forces to the measurement sensors

Inventive Principle:
Principle #30Flexible shells and thin films

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

Enables precise detection of collision mass and reduces unintended braking by accounting for collision intensity and vehicle speed, enhancing safety and operational efficiency.

Implementation Method 1

Each leaf spring has a measuring transducer in the form of a strain-voltage converter

Methodology Applied
Scientific EffectStrain-voltage conversion: Piezoelectric Effect

Implementation Method 2

Each leaf spring is subjected to bending stress in the event of a collision

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3116762B1Obstacle detection device for railway vehicles
Publication Date: 2024.04.17 SIEMENS MOBILITY AUSTRIA GMBH
  • EP3116762B1 patent drawingFigure 1
  • EP3116762B1 patent drawingFigure 2
  • EP3116762B1 patent drawingFigure 3

AI summary

The invention relates to a device for detecting obstacles for a rail vehicle (1), comprising a pilot bar (6), which is retained on the bogie frame (5) of the rail vehicle (1) in front of the wheelset (11) which is first in the direction of travel by means of a mounting retainer (7), wherein the mounting retainer (7) is formed by vertically arranged spring elements, in particular leaf springs (8), wherein each leaf spring (8) is fastened at an upper end (9) to the bogie frame (5) and at a lower end (10) to the pilot bar (6), wherein each leaf spring (8) has stress-strain converter (2), which is arranged between the upper end (9) and the lower end (10) on a broad surface (12) of a leaf spring (8), and wherein each stress-strain converter (2) is connected to an on-board evaluating unit (13) by means of a signal-conducting connection (13).