Rail Vehicle Derailment Detection via Torque Limiting

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Solution Overview

Problem

Existing methods for detecting a derailed rail vehicle condition, especially at low speeds, are not reliable and early enough, particularly for autonomously driving or automated rail vehicles.

Innovation Solution

A method and device that limit the drive torque to a predetermined value based on vehicle speed and position, generating a derailment signal if the speed falls below a threshold, with the ability to adapt to different positions and speeds, ensuring early detection of a derailed condition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing derailment detection methods are used, then detection capability is provided, but detection reliability at low speeds is insufficient

Engineering Contradiction:
Improvederailment detection reliabilityVSAvoidvehicle speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The system performs preliminary actions by limiting the drive torque to a maximum value before derailment can occur at low speeds. This preventive torque limitation creates controlled test conditions that enable early detection of derailment states before they develop into dangerous situations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the drive torque parameter by limiting it to a predetermined maximum value during detection phases. This parameter modification enables the system to operate in a controlled manner that makes derailment detection possible at low speeds where traditional methods fail.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If drive torque is limited to enable low-speed detection, then detection capability improves, but vehicle productivity decreases

Engineering Contradiction:
Improvederailment detection capabilityVSAvoidvehicle speed performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts the drive torque limitation based on operational context. The control device can modify the maximum torque value or deactivate the limitation when high-speed operation is required, allowing the system to adapt between detection mode (low speed, torque limited) and normal operation mode (high speed, full power) to balance safety and productivity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The derailment detection using torque limitation is performed periodically or at specific intervals rather than continuously. The system alternates between detection phases where torque is limited and normal operation phases where full power is available, enabling reliable low-speed detection while maintaining overall vehicle productivity.

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If position-dependent torque limitation is implemented, then detection precision improves, but device complexity increases

Engineering Contradiction:
Improvederailment detection precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control device performs multiple functions: it limits drive torque to a maximum value, determines vehicle position, compares position with stored reference positions, and controls the drive machine. By consolidating these functions in a single multi-functional control unit, the system achieves position-dependent torque limitation without proportionally increasing overall device complexity.

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

Data Source

PatentEP3988422B1Method and device for detecting a derailed state of a railway vehicle and railway vehicle
Publication Date: 2023.11.29 BOMBARDIER TRANSPORTATION GMBH
  • EP3988422B1 patent drawingFigure 1~2
  • EP3988422B1 patent drawingFigure 3~4

AI summary

The invention relates to a method for detecting a derailed state of a rail vehicle (1) comprising: - limiting a drive torque generated by a drive motor (2) of the rail vehicle (1) to a maximum value (AM_max), - determining a vehicle speed (v), - detecting the derailed state if the vehicle speed (v) is less than a speed threshold (v_th), as well as a device (6) and a rail vehicle (1).