Tyre Crown Sensor Calibration Using In-Use Motion Signals
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Solution Overview
Problem
Calibration of sensors mounted on the inner surface of tyres is difficult and costly due to the need for precise pre-calibration before mounting, which is time-consuming and resource-intensive.
Innovation Solution
A calibration method and system that calibrates sensors fitted at the crown portion of tyres during vehicle operation by acquiring motion signals, processing them to derive calibration physical quantities, and iteratively calculating and comparing values to achieve accurate calibration without pre-calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor calibration is performed using sophisticated instruments before mounting on the tyre, then measurement precision is improved, but loss of time and loss of substance increase due to time-consuming tests and costly machinery
Solution Approach 1:
The patent applies preliminary action by pre-calculating reference values for calibration physical quantities using a mathematical model before the actual calibration process. The system prepares expected acceleration values, angular velocity values, and footprint length values in advance based on tyre operating conditions, which then serves as a reference for comparing against sensor readings during calibration.
Solution Approach 2:
The patent replaces the mechanical calibration system (sophisticated instruments and test equipment) with a computational approach using a mathematical model. Instead of using physical calibration rigs to determine sensor accuracy, the system uses calculated reference values from tyre mechanics equations to perform calibration during normal operation, eliminating the need for complex mechanical calibration equipment.
2Measurement precision
If sensor calibration is performed using sophisticated instruments, then measurement precision is improved, but device complexity increases due to costly machinery and qualified personnel requirements
Solution Approach 1:
The patent implements self-service by enabling the sensor calibration system to calibrate itself using data from its own operation. The sensor mounted on the tyre continuously reads acceleration, angular velocity, and footprint length during normal vehicle operation, compares these readings against values calculated from the mathematical model, and automatically determines calibration coefficients without requiring external calibration equipment or specialized personnel.
Solution Approach 2:
The patent introduces a mathematical model of tyre mechanics as an intermediary between the sensor readings and the calibration process. This model acts as a mediator that translates operating conditions (angular velocity, vertical load, footprint length) into expected sensor readings, allowing calibration to be performed through computational comparison rather than direct physical measurement with sophisticated instruments.
3Ease of operation
If sensor is mounted on the inner surface of the tyre at the crown portion, then ease of operation is improved for detecting tyre behaviour, but calibration difficulty increases due to inability to apply known calibration methods
Solution Approach 1:
The patent applies parameter changes by utilizing the natural variation of operating conditions (angular velocity, vertical load, footprint length) during vehicle operation to enable calibration. Instead of requiring static calibration conditions, the system uses the dynamic range of operational parameters to gather multiple data points for determining calibration coefficients, transforming the calibration problem from a static measurement task to a dynamic parameter-based calculation.
Solution Approach 2:
The patent embraces dynamics by performing calibration during normal vehicle operation rather than requiring static calibration conditions. The system continuously collects sensor data across varying operating conditions (different speeds, loads, and footprint lengths) and uses this dynamic data set to determine calibration coefficients, making the calibration process adaptable to the actual operational environment of the tyre sensor.
Data Source
AI summary
Calibration method (200), and related system (100), of a sensor (70) for tyres, comprising, with the sensor (70) mounted at a crown portion (31) of a tyre (99) and during an advancement of a vehicle onto which the tyre (99) is fitted: a) acquiring (1), from the sensor (70), a motion signal representative of a motion of the crown portion (31); b) acquiring (2) a respective current value of one or more operating conditions of the tyre (99); c) processing (3) the motion signal for obtaining from the motion signal a first value representative of a calibration physical quantity associated with the motion of the crown portion (31) at said respective current value of the one or more operating conditions; d) calculating (4) a second value representative of the calibration physical quantity at the respective current value of the one or more operating conditions, by a predetermined mathematical correlation between the calibration physical quantity and the one or more operating conditions; e) iterating steps a), b), c) and d) for obtaining a first set of first values representative of the calibration physical quantity varying the respective current value of the one or more operating conditions, and a corresponding second set of second values representative of the calibration physical quantity; f) calibrating (6) the sensor (70) by a comparison between the first and second set.