Tire Load Estimation via Footprint Centerline Length
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Solution Overview
Problem
Existing tire load estimation methods face challenges in achieving accurate and reliable measurements, either through direct sensor measurements that are difficult to implement effectively or through techniques relying on fixed parameters that lead to suboptimal predictions.
Innovation Solution
A system and method that estimate tire load by measuring the footprint centerline length using sensors mounted on the tire, incorporating precalibrated sensitivity, reference footprint values, and reference load values, while excluding measurements during cornering, acceleration, or braking events, and accounting for variables like inflation pressure, camber angle, and tread depth, to provide a dynamic and accurate estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct measurement using load or strain sensors is used, then measurement precision is improved, but device complexity and ease of manufacture deteriorate
Solution Approach 1:
The patent replaces direct mechanical load/strain sensors with an optical measurement system that uses a marker on the tire and measures footprint length changes. This substitution eliminates the need for complex sensor construction on the tire while achieving accurate load estimation through optical tracking of footprint dimensions.
Solution Approach 2:
The patent introduces a marker as an intermediary element attached to the tire, which serves as a reference for measuring footprint length changes. This intermediary enables indirect measurement of tire load through footprint dimension changes rather than direct force measurement, simplifying the overall system while maintaining accuracy.
2Device complexity
If fixed parameters are used for tire load estimation, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent transitions from fixed parameter estimation to a dynamic measurement approach that continuously tracks footprint length changes. By monitoring the dynamic variation in footprint dimensions as the tire rotates, the system adapts to changing load conditions and provides accurate real-time load estimation without relying on predetermined fixed parameters.
Solution Approach 2:
The patent performs preliminary calibration by establishing the relationship between footprint length and load at known reference conditions. This preliminary action creates a calibration curve or lookup table that enables accurate load estimation during operation without requiring complex real-time calculations, thus maintaining system simplicity while improving precision.
3Productivity
If measurements are taken during all driving conditions, then productivity is improved, but measurement precision deteriorates due to cornering, acceleration, and braking events
Solution Approach 1:
The patent extracts and isolates only the straight-line driving portions from the overall driving data stream. By identifying and selecting measurements taken during straight-line driving conditions and excluding those during cornering, acceleration, or braking events, the system ensures high measurement precision while maintaining adequate productivity through continuous monitoring and selective data usage.
Solution Approach 2:
The patent implements feedback mechanisms that continuously monitor driving conditions (steering angle, brake status, acceleration) and use this information to validate whether current measurements should be accepted. This feedback loop ensures that only measurements taken under appropriate straight-line driving conditions are used for load estimation, maintaining precision while allowing continuous operation.
Data Source
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AI summary
A tire load estimation system and method is disclosed. The system comprisies at least one tire supporting a vehicle, the at least one tire including a pair of sidewalls extending to a circumferential tread; a sensor mounted to the at least one tire; a footprint formed by the tread, the footprint including a centerline with a footprint centerline length, wherein the sensor is configured to measure the footprint centerline length; and a tire load estimator. The tire load estimator is configured to receive as inputs: a pre-calibrated sensitivity, the footprint centerline length during straight-line driving conditions, a reference footprint value, and a reference load value, wherein the tire load estimator is configured to determine an estimation of tire load and is configured to output the estimation to at least one of a vehicle control system and a vehicle electronic control unit.