Sensor Array Sensitivity Gradient for Tyre Pressure Measurement
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Solution Overview
Problem
Existing systems for checking vehicle tire pressure using sensor arrays face challenges in accuracy and robustness, particularly when dealing with varying loads and tread patterns, which can lead to spurious or inaccurate results due to sudden changes in sensitivity.
Innovation Solution
A sensor array design featuring elongate sensor members with varying sensitivity from one end to the other, and a second set of sensor members positioned opposite to maintain maximum sensitivity, combined with a processing module to process outputs and provide accurate tire pressure data, eliminating crosstalk and ensuring robustness for heavy vehicle use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a linear array of sensors is used to measure tire pressure, then the device complexity is reduced, but the measurement precision deteriorates due to sudden changes in sensitivity and crosstalk
Solution Approach 1:
The patent applies local quality by making each sensor member non-uniform in its sensitivity distribution along its length. Specifically, each sensor member has higher sensitivity at one end and lower sensitivity at the other end, creating a gradient of sensitivity. This local variation in sensitivity prevents sudden changes in overall system sensitivity as the tire passes over, thereby maintaining measurement precision while using a relatively simple linear array structure.
2Manufacturing precision
If sensor members have uniform sensitivity along their length, then the manufacturing precision is improved, but the reliability deteriorates due to spurious results from sudden sensitivity changes
Solution Approach 1:
The patent deliberately introduces local quality variations in the sensor members by designing them with non-uniform sensitivity distributions. Each sensor member has controlled variations in sensitivity along its length, with higher sensitivity at one end and lower at the other. This design choice prioritizes measurement reliability over manufacturing simplicity, as the non-uniform sensitivity prevents spurious results while still being manufacturable with standard tolerances.
3Device complexity
If a single set of sensor members is used, then the device complexity is reduced, but the measurement precision deteriorates due to sensitivity drops at certain positions
Solution Approach 1:
The patent employs asymmetry by using two sets of sensor members with opposite sensitivity gradients. One set has higher sensitivity at the forward end, while the other set has higher sensitivity at the rear end. This asymmetric configuration ensures that as the tire passes over the array, at least one set of sensors is always operating at high sensitivity, eliminating the precision drops that would occur with a single symmetric set of sensors.
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 design enhances accuracy and reliability by maintaining maximum sensitivity throughout the tire's passage, reducing crosstalk, and providing robustness to withstand heavy loads, enabling precise tire pressure measurement even in complex tread patterns.
Implementation Method 1
each first sensor member is provided with a respective load sensing system which provides an output representing the load on the sensor member
Data Source
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AI summary
A sensor array (13) for checking the pressure of a vehicle tyre whilst being moved over the array comprises two sets (14) and (19) of aligned, facing sensor members. The first set (14) of sensor members is formed by slits (15) cut into a plate of metal to form first fingers (16) connected in cantilevered fashion to a first base portion (17), which extend in the direction of intended vehicle movement to free ends(18). The second set (19) of sensor members is formed by slits (20) cut into a plate of metal to form second fingers (21) connected in cantilevered fashion to a second base portion (22), which extend in the reverse of the direction of intended vehicle movement to free ends(23). The fingers of the two sets are aligned and the free ends (18) and (23) are closely adjacent. Each finger is provided with a load sensing system (28, 29) which provides an indication of the load on the finger as the tyre moves over the finger. Loads are applied to different positions along the fingers as the tyre moves over the array. The sensitivity of the array increases from a minimum for a load applied where the first fingers (16) are attached to the first base portion (17), to a maximum adjacent the free ends (18, 23) of the first and second fingers (16) and (21), and then decreases to a minimum where the second fingers (21) are attached to the second base portion (22). The fingers may be replaced by series of individual sensing elements (42) arranged in groups so as to constitute sensor members, whose outputs are weighted so that the sensitivity varies in a similar manner along a sensor member.