Road Surface Condition Detection Using Tire Vibration Windowing
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Solution Overview
Problem
Conventional methods for determining road surface conditions using tire vibration require measurement of wheel speed and detection of peak positions, leading to inaccurate region width setting and dependence on tire size, which limits their robustness.
Innovation Solution
A method that involves detecting tire vibration, deriving time-series waveforms, windowing them into predetermined time windows, calculating feature vectors, and using kernel functions to determine road surface conditions without measuring wheel speed or detecting peak positions, thereby improving robustness against tire size changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If peak position detection and wheel speed measurement are used to set region width, then road surface condition determination accuracy is improved, but device complexity and measurement requirements increase
Solution Approach 1:
The invention extracts and removes the problematic components (peak position detection and wheel speed measurement) from the road surface condition determination system. By using a fixed time width for region division instead of dynamically adjusting based on peak positions and wheel speed, the system eliminates the need for these additional measurements while maintaining determination accuracy through the fixed temporal framework.
Solution Approach 2:
The invention changes the parameter for region width determination from a dynamic parameter (based on wheel speed and peak positions) to a fixed parameter (predetermined time width). This parameter change simplifies the measurement system by eliminating the need for wheel speed sensors and peak detection algorithms, while the fixed time width ensures consistent analysis across different operating conditions.
2Measurement precision
If region width is adjusted according to tire size, then measurement accuracy for different tires is improved, but adaptability to various tire sizes decreases
Solution Approach 1:
The invention creates a universal determination method that works across different tire sizes by using a fixed time width for region division. This universal approach eliminates the need to recalibrate or adjust region widths for different tire specifications, making the system equally effective for various tire sizes without requiring tire-specific configuration.
Solution Approach 2:
Instead of adjusting the time width parameter to match tire characteristics (the conventional approach), the invention inverts the approach by fixing the time width and allowing the analysis to adapt to different tire sizes. This inversion makes the system more robust against tire size variations while maintaining determination accuracy.
Data Source
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AI summary
A time-series waveform of tire vibration detected by an acceleration sensor is windowed by a windowing means, time-series waveforms of the tire vibration are extracted for respective time windows, and feature vectors of the respective time windows are calculated. Then kernel functions are calculated from the feature vectors of the respective time windows and road surface feature vectors, which are the feature vectors for the respective time windows calculated from the time-series waveform of the tire vibration obtained for distinctive road surface conditions calculated in advance. And the road surface condition is determined by comparing values of discriminant functions using the kernel functions. As a result, the road surface condition can be determined from the time-series waveform of the tire vibration without detecting peak positions or measuring the wheel speed. Moreover, robustness against changes in tire size can be added to the determination of the road surface condition.