Coded Wheel Rotation Sensing with Signal Defect Correction
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Solution Overview
Problem
Magnetic sensors used for angular measurement of rotating members, such as automobile tires, often experience measurement errors due to variations in the electrical signal caused by factors like packaging tolerances, mechanical vibrations, temperature changes, and defects in the teeth or magnetic patterns, leading to incorrect speed indications and potential unnecessary activation of systems like ABS.
Innovation Solution
A sensing system and method that includes a coded wheel generating a varying signal, a sensor to detect this signal, and a correction module to compare the received signal with a stored signal to detect defects in the wheel, allowing for signal correction and preventing false speed indications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic sensors are used for angular measurement, then robustness and low production costs are improved, but measurement precision deteriorates due to signal variations from packaging tolerances, mechanical vibrations, temperature changes, and wheel defects
Solution Approach 1:
The system performs preliminary actions by storing reference signals corresponding to expected wheel patterns before actual measurement occurs. During operation, received signals are compared against these pre-stored references to detect defects, allowing the system to anticipate and compensate for potential measurement errors before they affect speed calculation accuracy.
Solution Approach 2:
The system implements feedback by continuously comparing received sensor signals with stored reference signals and using the difference information to detect wheel defects. This feedback mechanism allows real-time identification of signal anomalies caused by packaging tolerances, mechanical vibrations, or wheel defects, enabling correction of measurement errors in the speed calculation.
2Ease of operation
If signal processing is performed to convert sinusoidal signals into binary sequences, then rotational speed and angular position can be determined, but measurement errors increase due to displacement of peak and zero value positions in the signal
Solution Approach 1:
The system creates a copy of the expected signal pattern by storing reference signals that represent the ideal sinusoidal waveform for a perfect wheel. During measurement, the actual received signal is compared against this stored reference copy, allowing the system to identify and correct deviations caused by packaging tolerances, mechanical vibrations, or wheel defects, thereby maintaining angular position accuracy while preserving ease of operation.
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
The system effectively corrects signal anomalies caused by wheel defects, ensuring accurate rotational speed measurements and preventing unnecessary system activations by distinguishing between defects and actual speed changes.
Implementation Method 1
as the toothed or magnetically patterned regions pass the sensor a magnetic field is induced
Implementation Method 2
The magnetic field sensor element (for example, Hall-effect sensor, Giant Magneto Resistance (GMR) sensor, etc.) converts the applied magnetic field into a proportional electrical signal
Data Source
AI summary
A sensing system and method. A coded wheel is configured to generate a signal that varies with rotation of the coded wheel. A sensor is configured to sense the varying signal and output a corresponding signal. A correction module is configured to receive the signal output by the sensor and compare the received signal to a stored signal and detect a defect in the coded wheel in response to the comparison.