Tire Radial Acceleration Sensing for Road Unevenness Estimation
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Solution Overview
Problem
Existing methods for estimating road unevenness lack direct knowledge of vehicle-road interaction at the tire-road contact area, leading to inaccuracies in measuring long-term irregularities, which affect vehicle comfort and wear.
Innovation Solution
Monitoring tire deformation variations using units embedded in tires, which measure radial acceleration over multiple rotations to correlate with vehicle body motions, allowing for the estimation of road unevenness parameters without dedicated hardware or complex software on the vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vehicle body motion is measured using accelerometers mounted in the vehicle, then vehicle body motion can be estimated, but the connection to road profile requires precise knowledge of suspension system response and tire features which vary over time
Solution Approach 1:
The patent introduces tire deformation as an intermediary parameter that directly reflects road profile characteristics. By measuring tire deformation variations through radial acceleration sensors mounted on the wheels, the system obtains direct information about road unevenness without needing to model the complex suspension system dynamics. The tire acts as a mechanical filter that translates road irregularities into measurable deformation patterns.
Solution Approach 2:
The patent replaces the traditional approach of using vehicle body accelerometers with a mechanical measurement system based on tire deformation. By mounting radial acceleration sensors directly on the wheels, the system substitutes the complex vehicle body motion analysis with direct tire-level measurements that inherently capture road profile information through the tire's mechanical interaction with the road surface.
2Measurement precision
If wheel slip ratio is measured to detect short term road irregularities, then micro, macro and mega textures can be estimated, but this method is not suitable for estimating long term irregularities (road unevenness)
Solution Approach 1:
The patent exploits the dynamic characteristics of tire deformation at different frequencies. By analyzing the temporal variations in radial acceleration signals, the system can distinguish between high-frequency short-term irregularities (micro, macro, mega textures) and low-frequency long-term irregularities (road unevenness). The dynamic response of the tire to different wavelength road features enables multi-scale road characterization through a single measurement system.
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 approach effectively estimates road unevenness parameters by linking tire deformation to vehicle body motions, providing accurate and detailed information on road conditions without the need for accelerometers or complex systems on the vehicle.
Implementation Method 1
measuring said quantity, descriptive of a respective deformation of said tires, at least during respective passages of said respective monitoring units in correspondence of said respective contact areas
Implementation Method 2
a tire deformation varies due to, also, to vehicle body motions
Implementation Method 3
a tire is deformed by vertical force due to the weight of the vehicle body so that a contact area is formed between a tire and a rolling surface
Data Source
Figure 1
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AI summary
A method and system for estimating an unevenness parameter of a road segment having a length (L) are disclosed; the method and system take into account road unevenness induced vehicle body motions and are based on the estimation of the deformation, over multiple tire rotations, of at least two tires fitted to different axles of a vehicle.