Tire Wear Estimation Using Size-Normalized Deformation Speed
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Solution Overview
Problem
Existing methods for estimating tire wear require extensive actual vehicle tests for each tire size to create a map showing the relationship between normalized deformation speed index and ground contact time ratio, making it inefficient for estimating wear in tires of other sizes.
Innovation Solution
A tire wear estimation method that uses an acceleration sensor to detect radial acceleration, calculates deformation speed indices, normalizes them with rotation time, and uses a CTR-P map to estimate wear, minimizing the influence of tire size by dividing the normalized deformation speed index by the tire's outer diameter, allowing for efficient estimation without extensive testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a map showing the relationship between normalized deformation speed index and ground contact time ratio is created through actual vehicle tests for each tire size, then measurement precision is improved, but loss of time and productivity deteriorate due to extensive testing requirements
Solution Approach 1:
The patent introduces a wear measure that incorporates tire outer diameter as a normalization parameter. By dividing the normalized deformation speed index by the tire outer diameter, the patent creates a size-independent parameter that allows wear estimation across different tire sizes without requiring separate calibration tests for each size, thus resolving the contradiction between measurement precision and testing time
Solution Approach 2:
The patent develops a universal wear measure and estimation method that can be applied to tires of various sizes using a single set of calibration data. The wear measure formula incorporates tire dimensions to normalize the deformation characteristics, making the estimation system universally applicable across different tire specifications without requiring size-specific calibration maps
2Measurement precision
If tire wear estimation is performed using normalized deformation speed index, then measurement precision is improved, but device complexity increases due to the need for extensive calibration data for different tire sizes
Solution Approach 1:
The patent simplifies the calibration data structure by introducing a wear measure that includes tire outer diameter normalization. This parameter change allows the calibration to be performed once with a single reference tire size, and the same calibration data can be used for tires of any size by applying the normalization formula, thereby reducing device complexity while maintaining measurement precision
3Ease of manufacture
If the influence of tire size is not minimized in wear estimation, then ease of manufacture is improved by treating each tire size independently, but adaptability deteriorates because the estimation method cannot be efficiently applied to tires of other sizes
Solution Approach 1:
The patent achieves both ease of manufacture and adaptability by introducing a wear measure formula that incorporates tire outer diameter normalization. This allows the estimation method to be manufactured once and applied universally to tires of any size, maintaining ease of implementation while significantly improving adaptability across different tire specifications
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 enables accurate and efficient estimation of tire wear across different sizes by minimizing the impact of tire size, allowing for precise wear measurement without the need for extensive vehicle testing for each tire size.
Implementation Method 1
a radial acceleration of the tire in the tire radial direction is detected by an acceleration sensor
Data Source
Figure 1
Figure 2~3
Figure 4~5(b)
AI summary
In order to provide a method for efficiently estimating a degree of wear of a tire, a tire wear estimation method is provided in which a normalized deformation speed index is set as a wear measure, the normalized deformation speed index being obtained by normalizing, by a rotation time of the tire, an index of a deformation speed near an edge of a tire contact patch, the index being calculated from magnitudes of peaks appearing in a radial acceleration waveform obtained by differentiating tire radial acceleration detected by an acceleration sensor,; and the degree of wear of the tire is estimated using the wear measure and a ground contact time ratio which is a ratio of a ground contact time with respect to the rotation time, in which the degree of wear of the tire is estimated using the wear measure, the ground contact time ratio, a worn tire approximate formula and an approximate formula when a tire is new, which have been obtained in advance and each represents a relationship between the wear measure and the ground contact time ratio obtained by running a plurality of tires having tire sizes different from each other.