Rail Vehicle Adhesion Determination via Target Slip Control

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Solution Overview

Problem

Current methods for determining adhesion characteristics in rail vehicles are not sufficiently precise, leading to inefficient power transmission, increased braking distances, and wear on wheels and rails, especially in low adhesion conditions.

Innovation Solution

A method that forms time-dependent adhesion-slip characteristics using an adhesion model, environmental information, and drive and brake models to determine target slips, which are then used for control and wear prognosis, reducing errors and improving traction and braking forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional adhesion determination methods are used, then device complexity is reduced, but measurement precision deteriorates leading to insufficient precision in adhesion characteristics determination

Engineering Contradiction:
Improveprecision of adhesion characteristics determinationVSAvoidcomplexity of determination system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the adhesion determination process into multiple independent measurement components: wheel rotation speed measurement, vehicle speed measurement, slip calculation, and adhesion coefficient determination. This segmentation allows each component to be optimized independently while maintaining overall system precision without excessive complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces slip as an intermediary parameter that connects wheel rotation speed and vehicle speed measurements to adhesion coefficient determination. This intermediary enables precise adhesion measurement by providing a bridge between directly measurable quantities and the desired adhesion characteristic

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If adhesion characteristics are not precisely determined, then device complexity is reduced, but power transmission efficiency deteriorates leading to inefficient power transmission

Engineering Contradiction:
Improvepower transmission efficiencyVSAvoidprecision of adhesion characteristics
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements feedback by continuously determining adhesion characteristics and using this information to optimize power transmission. The system measures wheel rotation speed and vehicle speed, calculates slip, determines adhesion coefficients, and uses this feedback loop to maintain efficient power transmission by adjusting operations based on actual adhesion conditions

Inventive Principle:
Principle #23Feedback

3Reliability

If adhesion characteristics are not precisely determined, then device complexity is reduced, but braking distance increases leading to longer braking distances

Engineering Contradiction:
Improvebraking distance complianceVSAvoidprecision of adhesion characteristics
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by determining adhesion characteristics in advance before braking operations are required. This allows the system to know the current adhesion conditions and prepare appropriate braking strategies, ensuring compliance with braking distances by having precise adhesion information available before it is critically needed

Inventive Principle:
Principle #10Preliminary action

4Strength

If adhesion characteristics are not precisely determined, then device complexity is reduced, but wear and tear increases on wheels and rails

Engineering Contradiction:
Improvewheel and rail durabilityVSAvoidprecision of adhesion characteristics
Core Design Contradiction:
StrengthVSMeasurement precision

Solution Approach 1:

The patent enables the wheel-rail system to serve itself by continuously monitoring adhesion characteristics and using this information to optimize operations. The system automatically adjusts based on determined adhesion coefficients, preventing conditions that would lead to excessive wear and tear on wheels and rails through precise, continuous measurement

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3461675B1Method and device for determination of press-fit characteristics
Publication Date: 2020.07.08 SIEMENS MOBILITY AUSTRIA GMBH
  • EP3461675B1 patent drawingFigure 1
  • EP3461675B1 patent drawingFigure 2~3
  • EP3461675B1 patent drawingFigure 4

AI summary

The invention relates to a method and a device for determining friction characteristics in vehicles, particularly rail vehicles, for which information from at least one first vehicle (1) is used. To create favorable process conditions, it is proposed that time-dependent friction slip characteristics be generated, that target slip values ​​be determined from the friction slip characteristics, and that vehicle movements be influenced by means of the target slip values. This results in safer, energy-efficient, and low-wear operation of vehicles.