Vehicle Tyre Friction Estimation Using Kinematic Thresholds
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Solution Overview
Problem
Current methods for estimating potential friction between a vehicle tire and a rolling surface lack correlation between the slope of the linear region and actual friction levels, making it difficult to accurately determine friction thresholds and distinguish between different friction conditions.
Innovation Solution
A method and system that utilize kinematic quantity and engaged friction thresholds to compare current working points with reference curves, allowing for precise estimation of potential friction by identifying distinct thresholds where curves become distinguishable, enabling early detection of high-risk friction conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to estimate potential friction, then the estimation process can be performed, but the correlation between the slope of the linear region and actual friction levels is poor, making it difficult to accurately determine friction thresholds
Solution Approach 1:
The patent changes the approach from using the slope of the linear region to using the position of the working point relative to reference curves. By comparing the working point (engaged friction, kinematic quantity) with pre-established reference curves corresponding to different potential friction values, the system achieves accurate friction threshold determination. This parameter change transforms the estimation method from slope-based to position-based, resolving the correlation issue.
2Measurement precision
If high slip or engaged friction values are required to identify friction conditions, then friction levels can be determined, but the detection is delayed and safety response is slower
Solution Approach 1:
The patent establishes pre-defined reference curves corresponding to different potential friction values before operation. During operation, the system simply needs to determine where the current working point lies relative to these pre-established curves, eliminating the need to wait for high slip or engaged friction values. This preliminary action enables early detection of friction conditions at any operating point.
3Ease of operation
If the linear region is used for friction estimation, then the measurement process is simple, but the distinction between different friction conditions is poor due to curve overlap
Solution Approach 1:
The patent moves from one-dimensional slope measurement in the linear region to two-dimensional position analysis relative to reference curves. By considering both engaged friction and kinematic quantity dimensions simultaneously and comparing the working point position against reference curves, the system achieves clear distinction between different friction conditions while maintaining operational simplicity.
Data Source
AI summary
A method and system for estimating the potential friction between a tire and a rolling surface in which: a first and second engaged-friction/kinematic-quantity reference curve respectively corresponding to a first and to a second reference value μρ1, μP2 of potential friction with μP2>μP1 are provided; a first and a second kinematic quantity threshold value or a first and a second engaged friction threshold value are provided; the engaged friction μ between the tire and the rolling surface is determined; a current value of a kinematic quantity between the tire and the rolling surface is determined; a current working point given by the engaged friction μ and the current value of the kinematic quantity is determined; and the current value of the kinematic quantity is compared with the first and the second kinematic quantity threshold value or, respectively, the engaged friction μ is compared with the first and the second engaged friction threshold value.