Laser Track Position Measurement Using Angle Chords

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Solution Overview

Problem

Existing track position measurement methods are inefficient in curved tracks, especially when fixed point values are missing, as they struggle to provide a coherent spatial image and long-wave error compensation.

Innovation Solution

A method utilizing a laser reference system with an independently movable measuring carriage and an inertial measurement system to continuously measure the angle of long chords, allowing for the calculation of spatial coordinates and integration to determine the actual spatial position of the track, which is then smoothed using a long-wave compensation curve for error elimination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional track measurement methods are used in curved tracks without fixed points, then measurement capability is lost, but the patent introduces angle measurement of long chords to achieve coherent spatial imaging

Engineering Contradiction:
Improvetrack position measurement accuracyVSAvoidapplicability to curved tracks without fixed points
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical/fixed-point-based measurement system with an optical angle measurement system. Instead of relying on physical fixed points and mechanical chord measurements, the invention uses a laser transmitter to project long chords and measures angles optically, enabling measurement in curved tracks without fixed points.

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

Solution Approach 2:

The patent transitions from one-dimensional linear measurement (along the track) to two-dimensional angular measurement. By measuring angles of long chords relative to the track centerline, the system gains the ability to determine spatial position in curved geometry, adding a dimensional aspect to the measurement capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of information

If fixed point values are used for track measurement, then absolute position can be determined, but the method fails in curved tracks where fixed points are missing

Engineering Contradiction:
Improvefixed point data availabilityVSAvoidspatial image coherence
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The patent enables the measurement system to be self-sufficient by eliminating the external dependency on fixed points. The angle measurement of long chords provides intrinsic reference information that allows the system to determine track position and curvature autonomously, without requiring external fixed point infrastructure.

Inventive Principle:
Principle #25Self-service

3Productivity

If conventional measurement methods are applied, then simple track sections can be measured, but long-wave error compensation across multiple sections cannot be achieved

Engineering Contradiction:
Improvemeasurement coverage areaVSAvoiderror compensation capability
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent merges multiple measurement sections into a unified spatial model through angle measurements. By continuously measuring angles of long chords across consecutive sections and integrating them with inertial navigation data, the system creates a coherent spatial image that spans multiple sections, enabling error compensation over long wavelengths.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements feedback through the integration of angle measurements with inertial navigation system (INS) data. The angle measurements provide corrective feedback to the INS drift, allowing for long-wave error compensation by comparing the optically measured positions with the inertially predicted positions and adjusting accordingly.

Inventive Principle:
Principle #23Feedback

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 coherent spatial imaging of curved tracks without fixed point data, allowing for effective long-wave error compensation and absolute position marking, with the option to integrate fixed points for further correction.

Implementation Method 1

a laser transmitter (13) that can be moved independently on the track (3)

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

an inertial measurement system (IMU) (19) arranged on this measurement axis (18)

Methodology Applied
Scientific EffectInertial measurement: Inertia

Data Source

PatentEP2176465B1Method for measuring a track position
Publication Date: 2011.01.12 FRANZ PLASSER BAHNBAUMASCHINEN IND GMBH
  • EP2176465B1 patent drawingFigure 1~3

AI summary

The measurement of a track position occurs in consecutive measurement sections (15), wherein the relative track position is registered with the aid of a longitudinal rule (17) formed by a laser beam (16) as the reference line of a measurement system (9), wherein an angle formed by the longitudinal rules (17) of two consecutive measurement sections (15) is measured so as to thus obtain a spatial curve reflective of the actual position of the track.