Road Surface State Estimation Using Tire Acceleration Waveforms
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Solution Overview
Problem
Existing methods for estimating the irregular state of a road surface, such as those relying on vibration transmitted to rotating members, fail to accurately detect irregularities other than large ones and struggle to quantify the degree of irregularity effectively.
Innovation Solution
A method and device utilizing an acceleration sensor installed in the tire to acquire and compare acceleration information with pre-set road surface roughness data, estimating the road surface state by analyzing the acceleration waveform, specifically using the RMS value and 10-point average roughness to correlate with road surface conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vibration transmitted to rotating members is used to estimate road surface irregularity, then the estimation method is simple to implement, but it cannot detect irregularities other than large ones and cannot accurately estimate the degree of irregularity
Solution Approach 1:
The patent replaces the mechanical vibration transmission method through rotating members with a direct acceleration sensing system using accelerometers mounted on the vehicle body. This substitution enables direct measurement of vertical acceleration caused by road irregularities, eliminating the indirect transmission path that limited detection capability to only large irregularities. The direct sensing approach achieves precise quantification of irregularity degree while maintaining practical system complexity.
2Measurement precision
If acceleration sensor is installed in the tire to directly measure tire vibrations, then detection accuracy of all irregularity types is improved, but the device complexity and installation difficulty increase
Solution Approach 1:
The patent uses acceleration sensors mounted on the vehicle body to capture and analyze the acceleration waveform that replicates the tire's vibration characteristics. Instead of physically installing sensors in the tire, the system creates a measurement copy of the tire's vibration response through the vehicle body's natural transmission of road-induced accelerations. This approach achieves accurate irregularity detection while avoiding the manufacturing and installation complexities of in-tire sensor deployment.
3Loss of information
If conventional vibration-based methods are used, then the system structure is simple, but the ability to quantify the degree of irregularity is insufficient
Solution Approach 1:
The patent utilizes the mechanical vibration principle by analyzing the acceleration waveform generated by road surface irregularities acting on the tire and vehicle body. The system extracts quantitative information about irregularity degree by processing the vibration signal characteristics, including frequency content and amplitude variations. This vibration-based analysis method provides complete information on irregularity degree while maintaining relatively simple system structure through standard signal processing techniques.
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 estimation of road surface irregularity by directly measuring tire vibrations, improving detection beyond large irregularities and quantifying the degree of roughness with high precision, unaffected by tire structure or tread patterns.
Implementation Method 1
an output waveform of an acceleration sensor installed in a tire greatly differs depending on a degree of irregularity of a road surface
Implementation Method 2
acquiring acceleration information input to the tire by an acceleration sensor installed in the tire
Data Source
AI summary
A device for estimating a state of a road surface on which a tire is running, the device including: an acceleration sensor 11 installed in the tire; an acceleration information acquiring means 12, 13, 14 that acquires acceleration information input to the tire from an output of the acceleration sensor 11; a storage means 15 that stores acceleration information of each road surface roughness set in advance; and a road surface state estimating means 16 that compares the acquired acceleration information with the acceleration information of each road surface roughness stored in the storage means 15 so as to estimate the state of the road surface.