Railway Bogie Snaking Instability Suppression via Traction Motor Control

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Solution Overview

Problem

Current methods for detecting serpentine instability in railway vehicles lack reliability due to a large filtering range and absence of theoretical basis, leading to potential misjudgments and inability to effectively eliminate instability.

Innovation Solution

A system that calculates the vibration non-linear index from transverse acceleration signals using noise-aided EEMD and Hilbert-Huang Transform to determine serpentine instability, and controls traction motor speed through direct torque control to eliminate instability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If band-pass filtering with 0.5-10 Hz range is used to detect serpentine instability, then the detection system can identify vibration signals, but the large filtering range leads to misjudgments and reduced measurement precision

Engineering Contradiction:
Improvedetection reliabilityVSAvoidinstability judgment precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the detection parameter from simple amplitude threshold judgment to non-linear index calculation. By computing the non-linear index from the acceleration signal and comparing it against a threshold, the system achieves more precise and reliable instability detection without being constrained by broad frequency filtering ranges.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If only transverse vibration reduction is implemented, then the vibration amplitude decreases, but the serpentine instability cannot be effectively eliminated

Engineering Contradiction:
Improvetransverse vibrationVSAvoidinstability elimination effectiveness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent replaces the mechanical vibration reduction approach with an electrical control system. By detecting the non-linear index and sending control signals to adjust traction motor speed, the system fundamentally eliminates serpentine instability at its source rather than merely suppressing vibration symptoms.

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

3Reliability

If traction motor speed is reduced based on non-linear index detection, then serpentine instability is eliminated, but the control system complexity increases

Engineering Contradiction:
Improveinstability suppression effectivenessVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a feedback control loop where the non-linear index is continuously calculated from acceleration signals, compared against a threshold, and used to generate control signals that adjust traction motor speed. This closed-loop feedback mechanism achieves reliable instability suppression through a structured yet manageable control architecture.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3437918B1Railway vehicle snaking instability suppression system and method
Publication Date: 2021.10.20 CRRC QINGDAO SIFANG CO LTD
  • EP3437918B1 patent drawingFigure 1
  • EP3437918B1 patent drawingFigure 2
  • EP3437918B1 patent drawing

AI summary

A system and method for suppressing serpentine instability of a railway vehicle, comprising a serpentine warning and control module for determining whether a bogie is in a state of serpentine instability; a traction motor speed control system for controlling a rotation speed of a traction motor according to a determination from the serpentine warning and control module; a signal output end of the serpentine warning and control module is connected with the traction motor speed control system. In the present disclosure, it extracts the serpentine characteristic wave from the transverse acceleration of the bogie and calculates the vibration non-linear index according to the extracted serpentine non-linear characteristic to judge whether the bogie is in a state of serpentine instability, and controls a direct torque of the traction system through the DTC control module. The existing transverse control of the train can only reduce the transverse vibration of the train and cannot eliminate the serpentine instability. However, the present disclosure can control the traction motor to reduce the speed and eliminate the serpentine instability.