Magnetic Angle Measurement with Dual Tracks for Absolute Positioning
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Solution Overview
Problem
Existing angle measurement systems based on magnetic methods struggle to accurately measure absolute angles with high resolution when a motor is stopped or rotated, particularly due to limitations in resolving phase differences between magnetic field signals from multiple tracks.
Innovation Solution
An angle measurement system utilizing a magnet with two annular tracks, where sensors measure sinusoidal magnetic field signals with 90-degree phase differences, and an absolute angle calculation unit processes these signals to calculate main, sub-section, and signal section values, enabling precise angle determination by dividing the rotation into sections and accounting for phase shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple tracks are used to increase resolution, then measurement precision improves, but device complexity increases
Solution Approach 1:
The angle measurement system divides the measurement range into multiple tracks (first track and second track), with each track further divided into multiple sections. This segmentation allows high-resolution angle measurement to be achieved by combining results from multiple simpler track measurements, rather than requiring a single complex high-resolution track.
Solution Approach 2:
The patent transitions from single-track measurement to multi-track measurement, adding a dimensional aspect to the measurement system. By measuring angles across multiple tracks with different phase relationships and combining the results through section division and calculation, the system achieves higher effective resolution than any single track could provide alone.
2Measurement precision
If phase difference measurement is performed to improve accuracy, then measurement precision improves, but difficulty of detecting and measuring increases
Solution Approach 1:
The system pre-divides the measurement range into main sections and sub-sections before performing phase difference measurements. By establishing these divisions in advance and using them as reference frameworks, the complex phase difference calculations are broken down into manageable steps, reducing the overall difficulty of detection and measurement.
Solution Approach 2:
The patent introduces section division values and reference tracks as intermediaries between the raw magnetic field signals and the final absolute angle measurement. These intermediaries simplify the phase difference analysis by providing structured reference points and reducing the computational complexity of directly measuring phase differences across the entire measurement range.
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 high-resolution measurement of absolute angles at both stopped and rotated motor positions, improving accuracy through detailed sectioning and phase consideration, thereby enhancing the system's ability to capture precise rotational data.
Implementation Method 1
sensors H1 and H2 capable of measuring a magnetic field signal of each of the two tracks TR1 and TR2
Data Source
AI summary
An angle measurement system using a magnet and provided with first and second tracks includes an absolute angle calculation unit configured to calculate an absolute angle of a position of the magnet by using a 1-1th digital signal obtained by measuring a magnetic field signal of the first track and converted into a digital signal, a 1-2th digital signal obtained by measuring the magnetic field signal of the first track and converted into a digital signal, a 2-1th digital signal obtained by measuring a magnetic field signal of the second track and converted into a digital signal, and a 2-2th digital signal obtained by measuring the magnetic field signal of the second track and converted into a digital signal.