Rail Wheel Geometry Estimation from Axle Box Vibration Spectra
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Solution Overview
Problem
Existing methods for determining wheel geometry in vehicles, particularly rail vehicles, are often costly and require retrofitting rotational speed sensors, and there is a need for precise and simple methods that can utilize existing acceleration sensors without additional cabling.
Innovation Solution
A vibration-based method using amplitude sum spectra to determine wheel harmonics from vertical acceleration signals, which are filtered to exclude interference frequencies, allowing for accurate wheel geometry determination using standard travel speeds and existing acceleration sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rotational speed sensors are installed to determine wheel geometry, then measurement precision is improved, but device complexity and material costs increase
Solution Approach 1:
The patent replaces mechanical rotational speed sensors with a vibration-based measurement system using acceleration sensors. The method analyzes vertical acceleration signals to extract wheel harmonics and determine wheel geometry, eliminating the need for direct mechanical sensing on the wheel while achieving comparable measurement precision.
Solution Approach 2:
The patent introduces acceleration sensors as an intermediary measurement device placed on the axle box bearing housing instead of directly on the wheel. These sensors capture vibration signals that contain wheel geometry information, serving as a mediator between the wheel rotation and the measurement system.
2Adaptability or versatility
If rotational speed sensors are retrofitted to existing vehicles, then wheel geometry determination is enabled, but ease of manufacture and installation deteriorate due to additional cabling and retrofitting requirements
Solution Approach 1:
The patent leverages existing acceleration sensors in the vehicle's vibration monitoring system for axle box bearing diagnostics. By repurposing these already-installed sensors for wheel geometry determination, the system eliminates the need for separate sensor installations, cabling, and power supply modifications.
Solution Approach 2:
The patent enables acceleration sensors to serve dual functions: their original purpose for axle box bearing diagnostics and the new function of wheel geometry determination. This multi-functionality allows a single sensor system to provide multiple measurement capabilities without additional hardware.
3Device complexity
If vibration-based methods are used to determine wheel geometry, then material costs are reduced, but measurement precision may deteriorate due to interference frequencies from other vehicle processes
Solution Approach 1:
The patent extracts the wheel harmonic frequencies from the complex vibration spectrum by identifying frequencies assigned to amplitude maxima. This extraction process separates the wheel geometry information from interfering vibrations caused by other vehicle processes, enabling precise measurement despite the presence of noise.
Solution Approach 2:
The patent uses standard travel speed information as a reference to identify and filter interference frequencies. By comparing the vibration spectrum against expected wheel harmonics based on known travel speeds, the system can distinguish between genuine wheel geometry signals and spurious vibrations from other sources.
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 precise wheel geometry determination with reduced material costs, eliminating the need for rotational speed sensors and providing reliable results even with unreliable travel speed information.
Implementation Method 1
vertical accelerations of at least one first wheel are ascertained using at least one first sensor
Data Source
AI summary
A method for ascertaining a geometry of a wheel for vehicles, in particular rail vehicles, wherein at least one first sensor is used to ascertain vertical accelerations of at least one first wheel, and travel speeds are processed and wherein amplitude spectra are formed based vertical acceleration signals that characterize the oscillatory behavior of the at least one first wheel, wherein an amplitude sum spectrum is formed from the amplitude spectra, at least one wheel harmonic is determined from at least one frequency of the amplitude sum spectrum that is assigned to the amplitude maximum of the amplitude sum spectrum, and the wheel geometry is ascertained from a standard driving speed, which defines a characteristic vehicle operating behavior, and from the at least one wheel harmonic such that a dedicated rotational speed sensor can be omitted.