Rail Vehicle Adhesion Estimation via Slip Correlation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current adhesion estimation methods for rail vehicle brakes are unreliable, leading to potential safety hazards due to undetected deteriorated adhesion between wheels and rails, resulting in energy wastage and discomfort for passengers, and existing systems cannot accurately determine adhesion levels without indirect and unreliable measurements.
Innovation Solution
An adhesion estimating device that redistributes overall braking demands into individual braking demands for each wheelset, using a detection system to correlate current adhesion values with wheel slip, allowing for precise estimation of adhesion levels and implementing a best stopping distance strategy to prevent excessive slip, while also equalizing brake wear and thermal load across different brakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If indirect measurement methods are used to determine adhesion level, then energy consumption is reduced and passenger comfort is maintained, but measurement reliability is insufficient
Solution Approach 1:
The system implements feedback by continuously monitoring wheel slip during braking operations and using this information to update adhesion estimates. The detection system provides real-time feedback on wheel rotation deviations, which are processed to adjust braking demands and improve adhesion measurement accuracy without requiring additional energy-intensive measurements.
Solution Approach 2:
The system uses the braking operations already necessary for train operation to serve the dual purpose of deceleration and adhesion measurement. By analyzing wheel slip that occurs during normal braking, the system self-determines adhesion levels without requiring separate measurement activities, thus maintaining energy efficiency while improving reliability.
2Measurement precision
If braking operations are performed to determine current adhesion level, then adhesion measurement is achieved, but energy is wasted and passenger comfort is deteriorated
Solution Approach 1:
Instead of performing full braking operations solely for measurement purposes, the system uses partial braking actions that occur naturally during train operation. By analyzing wheel slip during these partial braking events, the system obtains sufficient adhesion measurement data without the energy consumption and comfort degradation associated with dedicated braking tests.
3Reliability
If nominal deceleration curves with enlarged safety factor are used, then safety is improved, but braking efficiency is reduced
Solution Approach 1:
The system dynamically adjusts braking demands based on real-time adhesion estimates rather than using fixed nominal deceleration curves with enlarged safety factors. By continuously updating adhesion values from wheel slip data and adjusting braking forces accordingly, the system achieves both safety and braking efficiency, eliminating the need for conservative fixed-margin approaches.
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 accurate and reliable estimation of adhesion levels during normal braking, ensuring safe deceleration without excessive slip, reducing maintenance needs, and updating adhesion data for improved future track performance.
Implementation Method 1
brakes that can individually brake wheelsets of the rail vehicle
Implementation Method 2
equalizing brake wear and thermal load across different brakes
Implementation Method 3
a detection system to correlate current adhesion values with wheel slip
Data Source
Figure 1
Figure 2a~2b
AI summary
An adhesion estimating device (2) for a brake system (1) of a rail vehicle having brakes (3', 3", 3"', 3"") that can individually brake wheelsets of the rail vehicle is provided. The adhesion estimating device (2) comprises a braking demand distributing unit (4) for redistributing an overall braking demand into individual braking demands, wherein the braking demand distributing unit (4) redistributes the overall braking demand requested for a predetermined deceleration into different individual braking demands such that the individual braking demands result in the predetermined deceleration, and an evaluation unit (7) determining a correlation, between a current adhesion value allocated to a current individual braking demand, and a current slip of a wheel braked by the one of the brakes (3', 3", 3"', 3"") for estimating an adhesion value between the wheel and the rail.