Magnetic Encoder Angle Determination with Noise Suppression
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Solution Overview
Problem
Magnetic encoders are vulnerable to noise, phase fluctuations, DC offsets, amplitude fluctuations, and waveform distortions in their output signals, which affect the accuracy of angular speed and location measurements.
Innovation Solution
A method involving a bipolar magnet and a multipolar magnet, where angle data from both magnets is used to generate waveform signals, convert them into signals with similar cycles, calculate phase differences, and correct the signals to determine accurate absolute angles using stored data and signal processing circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic encoder is used to detect rotation, then angular speed and location can be detected, but the output signal is vulnerable to noise, phase fluctuations, DC offsets, amplitude fluctuations, and waveform distortions
Solution Approach 1:
The patent uses an intermediary signal processing mechanism that compares the actual waveform with an ideal waveform and calculates phase differences as a mediator between the noisy magnetic encoder output and the final angle calculation. This intermediary processing step filters out noise and stabilizes the signal before final measurement.
Solution Approach 2:
The patent implements feedback by continuously monitoring the waveform signals, calculating phase differences, and using this information to correct subsequent measurements. The system feeds back the phase difference information to adjust and stabilize the angular measurement process, improving both precision and reliability.
2Measurement precision
If phase difference correction is applied to magnetic encoder signals, then measurement accuracy improves, but signal processing complexity increases
Solution Approach 1:
The patent segments the signal processing into distinct modular steps: waveform generation, waveform comparison, phase difference calculation, and angle determination. Each step handles a specific aspect of the correction process, making the overall complex task manageable and implementable through structured processing stages.
Solution Approach 2:
The patent performs preliminary actions by pre-generating ideal waveforms and pre-establishing comparison criteria before actual measurement. The system prepares reference waveforms and processing algorithms in advance, so that during operation, only the critical phase difference calculation and correction steps are needed, reducing real-time processing complexity.
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 enhances the accuracy of angular measurements by correcting phase differences and waveform distortions, enabling precise detection of rotation cycles and angles despite manufacturing defects or assembly errors in the magnets.
Implementation Method 1
The output signal of the magnetic encoder includes a pair of a sine wave and a cosine wave, based on an induced voltage of a rotating magnetic field
Data Source
AI summary
A method of determining an angle by an encoder includes generating a first angle data based on a rotation of a bipolar magnet and a second angle data based on a rotation of the multipolar magnet; determining a first waveform signal based on the first angle data and a second waveform signal based on the second angle data; converting the first waveform signal into a third waveform signal having a cycle similar to the second waveform signal; calculating an angle result value as a function of the second angle data and a determined value about a location of a rotation cycle of the multipolar magnet based on a difference between the second waveform signal and the third waveform signal; and determining an absolute angle corresponding to the calculated angle result value based on stored angle data.