Tire Load Estimation via Pressure and Rotational Dynamics
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Solution Overview
Problem
Existing methods for estimating tire load require expensive and accurate accelerometers to achieve acceptable accuracy, making them costly and suboptimal for low-cost solutions.
Innovation Solution
A method that determines tire load using tire pressure, angular velocity, stiffness coefficients, and radial deformation, with compensation factors based on pressure, velocity, and stiffness, allowing for accurate estimation with standard, cost-effective accelerometers and accounting for tire wear and use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a suitably calibrated and accurate accelerometer is used to estimate radial tire displacement, then measurement precision is improved, but device cost increases
Solution Approach 1:
The patent changes the measurement parameters from direct radial acceleration to tangential acceleration, and further to rotational speed and tire pressure parameters. By integrating tangential acceleration to obtain rotational speed, and using pressure-sensitive rubber material properties, the system achieves accurate tire load estimation without requiring expensive radial accelerometers with large acceleration ranges.
Solution Approach 2:
The patent replaces the mechanical sensing approach (radial accelerometer) with a combined approach using pressure-sensitive rubber material properties and rotational dynamics. The flexible printed circuit board with pressure-sensitive rubber detects pressure changes during tire deformation, and this is combined with rotational speed data to calculate tire load, substituting the need for complex mechanical acceleration sensors.
2Measurement precision
If a radial accelerometer with large acceleration range is used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent fundamentally changes the parameters being measured from radial acceleration to tangential acceleration, rotational speed, and pressure. This parameter transformation simplifies the measurement system because tangential acceleration and rotational speed can be obtained from standard sensors, and pressure changes in the flexible circuit board are easier to measure than radial acceleration, reducing calibration complexity.
Solution Approach 2:
The patent segments the tire load estimation problem into multiple measurable components: tangential acceleration measurement, rotational speed integration, and pressure change detection. By dividing the complex radial acceleration measurement task into these simpler sub-measurements, the system reduces overall device complexity while maintaining accuracy.
3Ease of manufacture
If standard low-cost accelerometers are used, then device cost is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent merges multiple measurement approaches: pressure-sensitive rubber material detection, rotational speed measurement, and tire pressure monitoring. By combining these different sensing methods, the system compensates for the limitations of low-cost accelerometers and achieves accurate tire load estimation through the integrated analysis of multiple parameters.
Solution Approach 2:
The patent changes from measuring radial acceleration directly to measuring pressure changes in the flexible circuit board during tire deformation. Pressure-sensitive rubber material translates mechanical deformation into electrical signals that are easier to measure accurately with low-cost sensors, improving measurement precision while using inexpensive hardware.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate tire load estimation using low-cost hardware, maintaining accuracy over the tire's life by adjusting for wear and use, thereby providing a cost-effective solution.
Implementation Method 1
The flexible printed circuit board may include a piezoresistive material
Implementation Method 2
changes in the resistance of the piezoresistive material may be used to determine the degree of deformation of the flexible printed circuit board
Data Source
AI summary
Embodiments included herein are directed towards a method for estimating tire load. Embodiments may include determining a tire pressure associated with a tire and determining a tire angular velocity associated with the tire. Embodiments may further include obtaining one or more tire stiffness coefficients and determining a tire radial deformation based upon, at least in part, a length of a tire ground contact patch or a contact patch angle.