Track Geometry Measurement Using Inertial and Stereo Vision
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Solution Overview
Problem
Conventional methods for determining track geometry are inefficient in accurately recording and correcting track geometry defects, particularly due to the influence of traffic and climatic factors on ballasted tracks, and require manual documentation of reference points.
Innovation Solution
A track inspection vehicle equipped with an inertial measuring system, a non-contacting stereo camera system, and a GNSS receiving device records a three-dimensional trajectory of the track, subdivides it into sections, and calculates actual distances to virtual longitudinal chords, allowing for automated reference point determination and track geometry evaluation, enabling precise correction of track geometry defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods with manual documentation of reference points are used, then the measurement process is simpler, but the measurement precision and efficiency are reduced
Solution Approach 1:
The patent replaces manual mechanical documentation methods with an automated optical measurement system. A camera system captures images of reference points, and a computer automatically processes these images to determine track geometry, eliminating manual measurement and documentation while improving precision.
Solution Approach 2:
The patent creates an optical copy (image) of the reference points and track geometry rather than physically measuring them. The camera system captures visual information that can be digitally processed to extract geometric data, replacing direct manual measurement with indirect optical copying.
2Productivity
If automated reference point determination is implemented, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent replaces manual reference point identification with an automated optical recognition system. The camera system automatically captures and identifies reference points in images, and computer algorithms automatically process this information to determine track geometry, significantly improving inspection productivity.
Solution Approach 2:
The system performs self-service automation where the measurement system itself automatically identifies reference points and processes geometry data without human intervention. The computer system autonomously processes camera images to determine track characteristics, eliminating the need for manual measurement and documentation.
3Measurement precision
If three-dimensional trajectory recording is used, then measurement precision is improved, but the difficulty of detecting and measuring increases
Solution Approach 1:
The patent replaces complex mechanical trajectory measurement systems with an optical camera system. The camera captures images that can be digitally processed to extract three-dimensional trajectory information, simplifying the measurement process while maintaining high precision through computational methods.
Solution Approach 2:
The patent transitions from two-dimensional manual measurement to three-dimensional digital analysis. By capturing images and processing them computationally, the system extracts spatial trajectory information in multiple dimensions, improving measurement precision while the computational approach simplifies the overall measurement process.
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
This method simplifies the evaluation and correction of track geometry defects by providing accurate, automated data for track maintenance, allowing for efficient comparison with predefined target geometries and derivation of correction values for on-track machines, thereby improving the accuracy and efficiency of track geometry adjustments.
Implementation Method 1
a three-dimensional trajectory of the track is recorded by means of an inertial measuring system arranged on the track inspection vehicle
Implementation Method 2
By means of pattern recognition, an evaluation device determines whether a reference point is depicted in one of the image pairs. In a further step, the position of a detected reference point is determined by evaluating the disparity.
Implementation Method 3
GNSS positions of the track inspection vehicle are recorded by means of a GNSS receiving device
Data Source
AI summary
A method for determining an actual geometry of a track by a track inspection vehicle which is movable on the track, wherein reference points positioned in a lateral environment of the track are automatically recorded by a non-contacting recording system arranged on the track inspection vehicle and their respective actual distance from the track is determined. A three-dimensional trajectory of the track is recorded by an inertial measuring system arranged on the track inspection vehicle, wherein the trajectory is divided by a computing unit into trajectory sections each having a section starting point related to a first reference point and a section end point related to a second reference point, wherein a virtual longitudinal chord is defined for each trajectory section in relation to the assigned reference points, and wherein actual distances between the trajectory and the respectively defined longitudinal chord are calculated for each trajectory section.