Wheel Lateral Localization Using Accelerometer Phase-Shift
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Solution Overview
Problem
Existing tire pressure monitoring systems face challenges in accurately and efficiently localizing wheel positions due to costly and complex antenna setups, and methods using accelerometers are limited by battery life and interference from vehicle dynamics.
Innovation Solution
A method that calculates the interval between acceleration measurements based on wheel rotation speed and rim radius, using a minimum number of measurements per rotation to determine the phase-shift angle and wheel position, optimizing energy consumption and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acceleration measurements are performed continuously or at high frequency to quickly determine the phase-shift angle sign, then the reliability and speed of wheel localization is improved, but the battery lifetime is greatly reduced
Solution Approach 1:
The patent applies periodic action by performing acceleration measurements at specific intervals corresponding to wheel rotation periods rather than continuously. The measurement frequency is synchronized with the wheel rotation, taking measurements once per rotation or at key phases, which reduces overall energy consumption while maintaining sufficient data for reliable phase-shift angle determination.
Solution Approach 2:
The patent applies dynamics by adapting the measurement frequency and interval based on wheel rotation speed and rim radius. The system dynamically adjusts when measurements are taken based on actual operating conditions, performing measurements more frequently when needed (high speeds, small radii) and less frequently when conditions allow, optimizing the balance between reliability and energy consumption.
2Duration of action of moving object
If a long interval is set between acceleration measurements to conserve battery energy, then the battery lifetime is extended, but the number of measurements per wheel rotation becomes insufficient for reliable phase-shift angle determination
Solution Approach 1:
The patent applies parameter changes by adjusting the measurement interval based on wheel rotation parameters (speed and rim radius). The system calculates appropriate measurement intervals dynamically, changing the timing parameters to match the specific operating conditions, ensuring sufficient measurements are taken regardless of wheel size or speed while minimizing unnecessary measurements.
Solution Approach 2:
The patent applies preliminary action by pre-calculating the optimal measurement intervals based on known wheel parameters (rim radius) and current operating conditions (rotation speed). This allows the system to plan measurements in advance, ensuring that the minimum required measurements are taken at the right moments without wasting energy on excessive measurements.
3Reliability
If the number of acceleration measurements per wheel rotation is increased to ensure reliable phase-shift angle determination, then the reliability is improved, but the energy consumption and battery drain increase
Solution Approach 1:
The patent applies partial action by taking only the minimum necessary number of measurements per wheel rotation required to reliably determine the phase-shift angle sign. Rather than continuously sampling or taking excessive measurements, the system identifies and executes only the critical measurements needed, reducing energy consumption while maintaining sufficient reliability.
4Measurement precision
If three low-frequency radio antennas are used for wheel localization, then the localization capability is achieved, but the device complexity and cost increase
Solution Approach 1:
The patent applies the taking out principle by extracting the localization function from the complex antenna system and implementing it through a different mechanism - using accelerometers already present in the tire pressure monitoring system. This eliminates the need for additional LF antennas and their associated complexity, while achieving the same wheel localization capability through phase-shift angle measurement.
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
This approach allows for quick and reliable lateral wheel localization, minimizing battery drain and interference, while adapting to varying wheel speeds and rim sizes, thus enhancing the accuracy and efficiency of wheel position determination.
Implementation Method 1
two accelerometers disposed perpendicular to one another and measuring the acceleration of the wheel in such a manner that one accelerometer measures a radial component F1 of the acceleration, and that the other accelerometer measures a tangential component of the acceleration; the acceleration measurements from the two accelerometers being out of phase by a predetermined phase-shift angle
Data Source
AI summary
Method for localization of the lateral position of the wheels of a vehicle equipped with a tire pressure monitoring system. Each wheel of the vehicle includes an electronic unit fixed onto a rim of radius R. Each unit notably includes two accelerometers, disposed perpendicular to one another and one measuring a radial component F1 of the acceleration, and the other a tangential component F2 of the acceleration. These components are out of phase by a predetermined phase-shift angle α. The method includes:I) measuring, per wheel rotation, at given intervals of time (Tmeasurement), a number (N) of acceleration values by each of the accelerometers (5a, 5b),II) calculating a physical value (P) representative of the sign of the phase-shift angle α between the two accelerometers,III) determining the lateral position of the wheel, based on the physical value (P) representative of the sign of the phase-shift angle.