Active Steering Control for Railroad Wheel Axles

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Solution Overview

Problem

Railroad vehicles experience friction and abrasion issues when moving on curved tracks due to an angle of attack between the rail and wheel, which existing active steering solutions fail to adequately address, especially when curvature varies along the track.

Innovation Solution

A system that measures drive data to estimate the radius of curvature in real-time and adjusts the steering angle of the wheel and axle accordingly, using a combination of displacement sensors and GPS to calculate and control the optimal steering angle, reducing the angle of attack and associated friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed steering angle is applied to the wheel and axle, then the structure is simple, but the angle of attack cannot be reduced when curvature varies along the track

Engineering Contradiction:
Improveadaptability to varying curvatureVSAvoidsteering control system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The steering angle of the wheel and axle is made dynamically adjustable based on real-time curvature detection. The system continuously measures the curvature radius using sensors and automatically adjusts the steering angle to match the varying track conditions, transforming a static steering system into a dynamic one that adapts to changing curvature requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements a feedback control mechanism where curvature sensors continuously monitor the track curvature radius and feed this information back to the steering control unit. The control unit then adjusts the steering angle based on this feedback, creating a closed-loop system that maintains optimal steering angles despite variations in track curvature.

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If real-time curvature estimation and dynamic steering control are implemented, then the angle of attack is reduced, but the device complexity increases

Engineering Contradiction:
Improveangle of attack and frictionVSAvoidmeasurement and control system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system replaces complex mechanical steering adjustment mechanisms with an electronic control system. Curvature sensors and electronic controllers calculate and adjust the steering angle electronically, substituting mechanical complexity with electronic intelligence to reduce the angle of attack more effectively.

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

Solution Approach 2:

A curvature detection sensor system serves as an intermediary between the track geometry and the steering mechanism. This intermediary continuously measures curvature parameters and translates them into control signals that adjust the steering angle, mediating the interaction between the variable track curvature and the steering system.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the wheel and axle position is fixed, then the structure is stable, but friction and abrasion increase on curved tracks

Engineering Contradiction:
Improvefriction and abrasionVSAvoidsteering adjustment complexity
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The steering system operates autonomously by automatically detecting track curvature and adjusting the wheel and axle steering angle without manual intervention. The system serves itself by using onboard sensors to monitor conditions and make real-time steering adjustments, eliminating the need for external control while reducing friction and abrasion.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2517943B1Active steering control device and method for railroad vehicle
Publication Date: 2021.09.22 KOREA RAILROAD RESEARCH INSTITUTE
  • EP2517943B1 patent drawingFigure 1~2
  • EP2517943B1 patent drawingFigure 3
  • EP2517943B1 patent drawingFigure 4~5

AI summary

The present invention relates to an active steering control device and method for a railroad vehicle, and more specifically, to an active steering control device and method for a railroad vehicle, which can smoothly steer a moving railroad vehicle by estimating the radius of curvature of a curved line in real-time when the train moves on the curved line and controlling an optimal steering angle of the wheel and axle according to the estimated radius of curvature, and can remarkably reduce an angle of attack which exists between the curved line and the wheel and axle. The invention includes: a measurer that measures drive data of the moving railroad vehicle; an estimator that estimates the radius of curvature of the curved line on which the railroad vehicle is moving, by using the data measured in the measuring unit; a calculator that sets a target value of the steering angle of the wheel and axle of the moving railroad vehicle, by using the radius of curvature estimated in the estimator; a controller that generates a steering control signal on the wheel and axle by comparing an actual steering angle of the wheel and axle with the target value of the steering angle of the wheel and axle, which is set in the calculator; and an actuator that steers the wheel and axle using the steering signal of the controller.