Tire Load Estimation Using Footprint Length and Pressure Correction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for estimating tire load are either inaccurate due to direct measurement challenges or unreliable due to reliance on fixed parameters, which affects vehicle handling, safety, and performance.

Innovation Solution

A system and method that uses a sensor-mounted tire to measure inflation pressure and footprint length, with a processor-based system that applies correction factors for inflation, loading state, and wear to indirectly estimate tire load, incorporating a de-noising module and load determination model for accurate calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If direct measurement using load or strain sensors is used, then measurement precision is improved, but device complexity and reliability worsen due to construction and placement difficulties

Engineering Contradiction:
Improvetire load measurement precisionVSAvoidmeasurement reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent uses footprint length as an intermediary parameter to indirectly estimate tire load. Instead of directly measuring load with complex sensors, the system measures the footprint length (a simpler parameter) and uses it to infer the load through correction factors and algorithms, thereby avoiding the reliability issues of direct measurement sensors while maintaining measurement precision

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical load/strain sensors with a measurement system based on footprint length detection and computational algorithms. This substitution eliminates the need for complex mechanical sensors that are difficult to install and maintain, while achieving reliable tire load estimation through the relationship between footprint length and load

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If fixed parameters are used for estimation, then device complexity is reduced, but measurement precision worsens due to less-than-optimum predictions

Engineering Contradiction:
Improveestimation system complexityVSAvoidtire load estimation precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transforms the static fixed-parameter estimation approach into a dynamic system that adapts to changing conditions. By introducing correction factors for inflation pressure, loading state, and tire wear, the system continuously adjusts the estimation parameters based on current operating conditions, thereby maintaining high measurement precision without excessive complexity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the estimation parameters from fixed values to dynamic parameters that vary with inflation pressure, loading state, and tire wear. This allows the system to maintain high measurement precision across different operating conditions while keeping the device complexity manageable through a structured correction approach

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If multiple correction factors and modules are added, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvetire load estimation precisionVSAvoidsystem structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the complex estimation system into distinct functional modules: footprint length measurement, inflation pressure correction, loading state correction, tire wear correction, and final load calculation. This segmentation allows each module to handle a specific aspect of the estimation, improving overall precision while making the system structure more manageable and easier to implement

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4140777B1Tire load estimation system and method
Publication Date: 2025.01.01 THE GOODYEAR TIRE & RUBBER CO
  • EP4140777B1 patent drawingFigure 1
  • EP4140777B1 patent drawingFigure 2
  • EP4140777B1 patent drawingFigure 3

AI summary

A system (10) and a method for estimating the load of a tire (12) is disclosed. The method comprises: mounting a sensor (26) to the tire (12); measuring an inflation pressure (40) of the tire (12) with the sensor (26); measuring with the sensor (26) a length of a footprint (32) formed by the tread (20); providing a processor (28) in electronic communication with the sensor (26); determining a loading state (54) of the vehicle (14) with a vehicle loading state estimator (62); determining an inflation correction factor (76) from the loading state (54) of the vehicle (14); determining an adjusted footprint length (78) with a pressure correction module (42), the pressure correction module (42) receiving the measured footprint length (38), the measured inflation pressure, and the inflation correction factor (76); generating a filtered footprint length (88) with a de-noising module (64), the de-noising module (64) receiving the adjusted footprint length (78); generating a wear-corrected footprint length (106) with a wear correction module (90), the wear correction module (90) receiving the filtered footprint length (88); and determining an estimated load (94) on the tire (12) with a load determination model (92), the load determination model (92) receiving the wear-corrected footprint length (106).