Rotation Direction Detection via Acceleration Signal Correlation
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Solution Overview
Problem
Existing methods for determining the direction of rotation of rotating bodies, such as vehicle tires, fail to accurately establish the phase relationship of acceleration signals and handle sinusoidal signals overlaid with rotational speed-dependent mean values due to centrifugal forces.
Innovation Solution
The method involves measuring two acceleration signals x and y, which are 90° apart, mathematically differentiating them, and correlating the signals to determine the direction of rotation, effectively eliminating mean values and reducing noise through correlation functions, allowing for stable direction-of-rotation detection despite small angular deviations and changing rotational speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase relationship evaluation of acceleration signals is used for direction of rotation detection, then direction detection capability is provided, but the method cannot accurately establish the phase relationship due to centrifugal force interference
Solution Approach 1:
The patent extracts and removes the centrifugal force component (mean value) from the acceleration signals through mathematical differentiation. By differentiating the acceleration signals, the method separates the rotational component (sinusoidal variation) from the centrifugal force component (constant mean value), allowing accurate phase relationship evaluation without centrifugal interference
Solution Approach 2:
The patent changes the parameter domain of the acceleration signals by applying mathematical differentiation. This transformation converts the signals from a domain where centrifugal forces create misleading mean values to a domain where the differentiated signals reveal the true phase relationships through correlation analysis
2Reliability
If acceleration signals are measured to determine direction of rotation, then direction detection is enabled, but computational complexity increases due to signal processing requirements
Solution Approach 1:
The patent replaces complex mechanical or hardware-based direction detection mechanisms with a mathematical signal processing approach. By using differentiation and correlation functions, the system achieves reliable direction detection through computational methods rather than complex physical mechanisms
Solution Approach 2:
The patent creates a simplified mathematical model (correlation function) that copies the essential characteristic of phase relationship without requiring direct measurement of the complex physical signals. The correlation function serves as a mathematical copy that reveals direction information while filtering out noise and centrifugal interference
3Adaptability or versatility
If phase difference evaluation is used for side localization, then localization capability is provided, but the method fails to provide specific evaluation solutions and cannot handle sinusoidal signals with mean values
Solution Approach 1:
The patent performs preliminary signal processing (differentiation) before the actual direction detection and localization evaluation. By pre-processing the acceleration signals to remove centrifugal force components, the method simplifies subsequent localization calculations and provides a clear implementation path for side localization
Solution Approach 2:
The patent introduces mathematical differentiation and correlation functions as intermediary processing steps between raw acceleration signal measurement and final direction/localization determination. These intermediaries transform the complex signals into a form that is easier to evaluate and implement
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 enables accurate and efficient determination of the direction of rotation with reduced computational overhead and noise, suitable for real-world applications like tire pressure monitoring systems, by correlating differentiated acceleration signals and accounting for centrifugal and gravitational accelerations.
Implementation Method 1
The direction-of-rotation detection is based on the evaluation of the phase displacement of the acceleration signals of the sensors for the x and y direction, produced due to the gravitation g.
Implementation Method 2
the processing of the sinusoidal signals which are overlaid with rotational speed-dependent mean values due to the centrifugal forces
Data Source
AI summary
A method determines a direction of rotation of a rotating body about its axis of rotation by measuring two acceleration signals x and y with an acceleration sensor. The two acceleration signals x and y are at a 90° angle to each other, are oriented not parallel to the axis of rotation, and both a centrifugal acceleration generated by a circular movement and a gravitational acceleration are taken into account. The measured acceleration signals x and y are differentiated mathematically. The differentiated x acceleration signal is differentiated a further time and correlated with a y signal that has been differentiated once for obtaining a correlation function. The differentiated y acceleration signal can be differentiated a further time and correlated with the x signal that has been differentiated once for obtaining a second correlation function. The method determines the direction of rotation of rotating tires of a motor vehicle.