Tire Rolling Radius Adhesion Estimation Model
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Solution Overview
Problem
Existing methods for evaluating tire grip conditions on the ground are either indirect, prone to sensor placement issues, or provide late warnings of slipping, which can be unsafe for vehicle operation.
Innovation Solution
The method involves measuring and analyzing the rolling radius of the tire to determine the grip potential by establishing a model linking grip potential to rolling radius and vehicle parameters, using data from known driving conditions and applying it in real-time to assess adhesion coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is positioned in a tread pattern element to measure tangential forces, then adhesion potential can be determined, but the sensor is exposed to shocks and attacks making it difficult to position and maintain
Solution Approach 1:
The invention extracts the measurement function from the tread pattern element and relocates it to the wheel hub or wheel bearing assembly. This removes the sensor from the harsh contact environment while maintaining the ability to measure adhesion potential through alternative means (measuring wheel rotation characteristics rather than direct force measurement in the contact patch).
Solution Approach 2:
The invention introduces an intermediary measurement approach by measuring wheel rotation speed and comparing it with vehicle speed to infer adhesion conditions. Instead of directly measuring forces in the contact patch, the system uses the wheel's rotational behavior as an indirect indicator of grip conditions, avoiding the need for sensors in the harsh contact environment.
2Measurement precision
If circumferential distance variations of tire sidewall points are measured, then grip potential can be determined, but the method only provides relevant information when the vehicle is close to sliding conditions
Solution Approach 1:
The invention performs preliminary measurement of wheel rotation characteristics continuously under normal driving conditions to establish a baseline. By monitoring changes in rotational speed and comparing with vehicle speed in advance, the system can detect deteriorating adhesion conditions before sliding actually occurs, providing early warning to the driver.
Solution Approach 2:
The system continuously monitors wheel rotation speed and provides real-time feedback about adhesion conditions. By comparing the measured wheel rotation with expected rotation based on vehicle speed, the system generates continuous feedback about grip quality, enabling timely driver intervention before loss of control occurs.
3Measurement precision
If the rolling radius is measured to determine grip potential, then precise and timely assessment is achieved, but the method requires control of parameters linked to the vehicle to minimize measurement error
Solution Approach 1:
The invention uses existing vehicle systems (wheel speed sensors from ABS, vehicle speed sensors, and microcontroller units) to measure rolling radius and determine adhesion potential. By making existing multi-functional systems serve the additional function of adhesion measurement, the patent avoids adding complex dedicated measurement equipment while achieving precise grip assessment.
Data Source
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AI summary
A method for determining the adhesion potential of a tyre mounted on a wheel and rolling on a floor, comprising the steps that involve: - assessing the change in the rolling radius of the tyre depending on predefined rolling conditions of said tyre on floors having variable and known adhesions, in order to form an experimental database, - based on the experimental database, establishing an estimation model of the adhesion potential (Mpotad) by determining a function linking the adhesion potential (/ima¾) to the rolling radius (RRt) and to vehicle parameters, while the tyre is rolling, determining the rolling radius (RRt) and, by applying said model (Mpotad), and depending on the vehicle parameters, assessing the adhesion potential {jimax) of said tyre.