Piezoelectric Tire Sensor Resonance Filtering
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Solution Overview
Problem
Existing tire monitoring systems face challenges in accurately determining operating parameters like contact patch length and load at low vehicle speeds due to resonance issues with oscillating piezoelectric elements, which can lead to incorrect data interpretation.
Innovation Solution
A method and system that utilize a piezoelectric element coupled to a tire's crown portion, processing the generated electrical signal by filtering out frequencies higher than the resonance peak frequency at low speeds to extract accurate information on contact patch length and load, and transmitting this data wirelessly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an oscillating piezoelectric element is used to generate electrical signals for determining tire operating parameters, then the system can operate at low speeds, but resonance issues occur that lead to incorrect data interpretation
Solution Approach 1:
The patent identifies resonance peaks in the electrical signal generated by the piezoelectric element and converts this harmful effect into a useful one by using the resonance frequency as a reference for filtering. The processing device detects the resonance peak frequency and uses it to determine a cutoff frequency for the low-pass filter, thereby transforming the resonance interference into a basis for accurate signal separation and measurement.
Solution Approach 2:
The patent introduces a low-pass filter as an intermediary component between the piezoelectric element and the measurement process. This filter acts as a mediator that separates the useful signal from the resonance noise by allowing frequencies below the resonance peak to pass through while attenuating higher frequencies, thus enabling accurate measurement of operating parameters even at low speeds.
2Measurement precision
If signal filtering is applied to remove resonance frequencies, then measurement accuracy improves, but signal processing complexity increases
Solution Approach 1:
The patent performs preliminary action by first detecting the resonance peak frequency from the electrical signal before applying the low-pass filter. The processing device identifies the resonance peak and uses it to set the appropriate cutoff frequency for filtering, ensuring that the filtering process is tailored to the specific resonance characteristics of the system rather than using a fixed or arbitrary filter setting.
Solution Approach 2:
The patent implements dynamic signal processing by adjusting the low-pass filter cutoff frequency based on the detected resonance peak frequency. Rather than using a static filter configuration, the system dynamically adapts the filtering parameters to match the actual resonance characteristics of the piezoelectric element, thereby optimizing measurement accuracy across different operating conditions.
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 reliable and accurate determination of tire operating parameters, including contact patch length and load, even at low speeds, by filtering out resonance-related noise, thereby improving the accuracy and reliability of tire monitoring systems.
Implementation Method 1
a piezoelectric element coupled to a housing (311) and being able to oscillate... causing oscillation of said oscillating structure, thereby causing said piezoelectric element to generate an electrical signal
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
An oscillating structure is coupled to a crown portion of a tyre. The oscillating structure comprises a housing and a piezoelectric element coupled to said housing. The piezoelectric element is able to oscillate in an oscillation direction, which could match either a longitudinal or a radial direction of the tyre. An electrical signal generated by said piezoelectric element is processed so as to determine at least one operating parameter of the tyre. The processing comprises determining whether a rotation speed of said tyre is greater than a threshold speed; and, in the negative, extracting information for determining the at least one operating parameter of the tyre from a low-pass filtered signal. Such low-pass filtered signal is obtained by removing at least frequency components of said electrical signal having a frequency higher than or equal to a resonance peak frequency of said oscillating structure.