Rail Vehicle Brake Actuator Speed Detection via Vibration Analysis

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Solution Overview

Problem

Current rail vehicle brake actuators are oversized due to assuming maximum speed in emergency braking without speed information, leading to increased costs and potential safety issues with braking distance and thermal overload, and rely on complex speed sensors that can fail, affecting braking force calculation and actuation.

Innovation Solution

A brake actuator that determines vehicle speed from the relationship between braking force and vibrations generated, using a single sensor to detect both, eliminating the need for redundant communication systems and speed sensors, and allowing speed-dependent emergency braking without external speed signals, with a control unit calculating coefficients for accurate braking force application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If brakes are dimensioned for maximum possible speed in fail-safe mode without speed information, then safety is improved, but device size and costs increase

Engineering Contradiction:
ImprovesafetyVSAvoidbrake size
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical speed sensors and communication systems with a vibration-based detection system. By measuring vibrations generated during braking and analyzing their frequency characteristics, the system determines vehicle speed without requiring traditional speed sensors or complex communication infrastructure. This substitution reduces device complexity while maintaining safety through accurate speed-dependent braking force calculation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The brake actuator performs self-diagnosis and self-determination of operating conditions by analyzing vibrations generated during its own operation. The system uses the vibrations produced by the braking process itself to determine speed, eliminating the need for external speed sensors or communication systems. This self-service approach reduces dependency on external components while maintaining accurate braking control.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If speed sensors and communication systems are used to determine braking force, then braking accuracy is improved, but device complexity and failure risk increase

Engineering Contradiction:
Improvebraking force calculation accuracyVSAvoidsensor and communication system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the braking function with the speed measurement function into a single integrated system. The brake actuator simultaneously applies braking force and measures vibrations to determine speed, eliminating the need for separate speed sensors and communication systems. This merging reduces device complexity while maintaining braking accuracy through the relationship between vibration frequency and vehicle speed.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The brake actuator is designed to perform multiple functions: applying braking force, generating controlled vibrations, measuring vibrations, determining speed, and calculating required braking force. This multi-functional design eliminates the need for separate dedicated speed sensors and communication infrastructure, reducing overall system complexity while maintaining measurement precision through the inherent relationship between braking-induced vibrations and vehicle speed.

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

3Device complexity

If a single sensor detects both braking force and vibrations, then component quantity is reduced, but measurement precision may be compromised

Engineering Contradiction:
Improvenumber of sensorsVSAvoidbraking force and vibration detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent employs a single multi-functional sensor that simultaneously detects both braking force magnitude and vibration characteristics. This sensor is strategically positioned to measure the reaction force generated by the braking process, which contains information about both the applied braking force and the vibrations produced. By analyzing the frequency spectrum of the detected signal, the system extracts speed information while maintaining measurement precision through the inherent coupling between braking force and vibration generation.

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

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 safe and efficient braking without oversizing, reduces component complexity and costs, and improves reliability by using vibrations to determine speed and calculate braking force independently of speed sensors, ensuring a shorter safety-relevant braking distance and reduced thermal overload risks.

Implementation Method 1

both the braking force and the vibrations generated by pressing against the brake disk can be easily detected in each brake actuator

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3676140B1Brake actuator for a rail vehicle
Publication Date: 2021.07.07 KNORR BREMSE SYST FUR SCHIENENFAHRZEUGE GMBH
  • EP3676140B1 patent drawingFigure 1

AI summary

The invention relates to a brake actuator (1) for a rail vehicle (2). The brake actuator (1) has a sensor (3) for detecting a braking force generated in the brake actuator (1), a sensor (4) for detecting vibrations generated by the braking force in the brake actuator (1), and a control unit (5). The control unit (5) is configured so as to generate a relationship between the speed of the rail vehicle (2) with a generated braking force and a frequency of the vibrations generated by the braking force.