Dynamic Contact Patch Control for Tire Wear Simulation
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Solution Overview
Problem
Laboratory tire test machines face challenges in simulating real-world tire tread wear due to geometry differences between curved test surfaces and flat road surfaces, and in maintaining consistent friction levels during testing, which affects the accuracy of tire tread wear measurements.
Innovation Solution
A tire testing machine equipped with sensors to measure parameters like contact patch length and friction, and a controlled system to adjust tire position, pressure, and material delivery based on real-time feedback, allowing for dynamic adjustment of the contact patch parameters to mimic real-world conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a curved surface or roller is used for tire tread wear testing, then the testing can be performed on a rotating element, but the geometry differences introduce inaccuracies compared to real-world flat road surfaces
Solution Approach 1:
The system dynamically changes the parameters of the contact patch (length, width, friction) by adjusting test variables such as tire inflation pressure, vertical load, and longitudinal force during the test. This allows the curved surface testing to produce results that more accurately represent flat road conditions by compensating for geometric differences through parameter adjustment
Solution Approach 2:
A sensor measures a parameter related to the contact patch (such as friction or contact length) in real-time, and this measurement is fed back to a controller that automatically adjusts test variables to maintain the desired contact patch characteristics. This closed-loop feedback system compensates for the curved surface geometry effects
2Reliability
If powder or particulate matter is applied to control friction, then friction between the tire and test surface can be controlled, but maintaining consistent friction levels throughout testing becomes difficult
Solution Approach 1:
A sensor measures friction or a related parameter at the contact patch in real-time, and this measurement is fed back to a controller that automatically adjusts the delivery rate of powder or particulate matter to the test surface. This maintains consistent friction levels throughout the test by compensating for changes in surface conditions, tire wear, and material consumption
Solution Approach 2:
The system transitions from static friction control (fixed powder application) to dynamic friction control, where the powder delivery rate is continuously adjusted during testing based on real-time measurements. This allows the friction level to be maintained within a desired range despite changing test conditions
Data Source
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AI summary
A tire testing machine (10) and a method for testing operating the same includes a tire and wheel assembly (17) having a sensor (40) configured to measure a parameter related to the tire and wheel assembly (17) as it rotates on a rotating element (12). A holder (19) supports the tire and wheel assembly (17). A processor (60, 90) is configured to receive an input at least based on the output signal from the sensor, and provide an output signal (64, 91) indicative of a parameter of a contact patch (24) between a tire (14) of the tire and wheel assembly (17) and the rotating element (12). Controlled element(s) (29, 132) are configured to vary a parameter related to the contact patch (24) and/or friction.