Angle Sensor Correction for Periodic Angular Errors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic angle sensors face challenges in reducing angular errors due to distorted waveforms of detection signals, which conventional correction methods fail to address effectively, especially when the angle to be detected varies with a predetermined period, leading to first-order and second-order errors.
Innovation Solution
An angle sensor system that includes a detection signal generation unit and an angle detection unit with a signal conversion operation using correction-term-containing functions to determine and apply correction terms, specifically for offset, amplitude, and phase corrections, to reduce first and second errors in the detected angle value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional offset correction and gain correction are applied to detection signals, then general signal quality is improved, but angular error reduction is insufficient when waveforms are distorted
Solution Approach 1:
The patent applies period-specific correction terms (first period correction term for the same period as the detection signal, second period correction term for half the period) to the conversion function. This changes the parameters of the correction approach from general offset/gain correction to specific periodic error correction, enabling effective reduction of both first-order and second-order angular errors that conventional methods cannot address
Solution Approach 2:
The patent performs preliminary determination of correction terms by detecting the detection signal over a predetermined period, calculating the first and second period correction terms based on the detected signal characteristics, and storing these terms for subsequent use. This preliminary action ensures that the correction terms are optimized for the specific signal waveform before actual angle detection begins
2Measurement precision
If detection signals are corrected to have less distorted waveforms, then angular error is reduced, but the operation becomes complicated
Solution Approach 1:
The patent extracts only the essential periodic error components (first period and second period correction terms) from the complex waveform distortion problem. Instead of attempting to correct all aspects of waveform distortion, the invention focuses on extracting and correcting the specific periodic error patterns that cause angular errors, thereby simplifying the correction operation while maintaining effectiveness
Solution Approach 2:
The patent changes the approach from complex waveform correction to simple parameter-based correction by determining correction terms based on signal period characteristics. This parameter change allows the system to handle angular error reduction through straightforward mathematical operations rather than complex waveform manipulation
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 reduces angular errors with a simple operation by converting detection signals into operation signals that minimize first and second errors, improving the accuracy of the detected angle value.
Implementation Method 1
The magnetic detection element includes, for example, a spin-valve magnetoresistance (MR) element
Data Source
AI summary
An angle sensor includes a detection signal generation unit for generating detection signals, and an angle detection unit for generating a detected angle value on the basis of the detection signals. The angle detection unit includes a signal conversion unit for performing a conversion operation, and an angle operation unit for performing an angle operation. The conversion operation is to convert the detection signals into first and second operation signals. The angle operation is to calculate the detected angle value using the first and second operation signals. The conversion operation includes an operation using a correction-term-containing function which contains a correction term for reducing a first error or a second error occurring in the detected angle value. When the angle to be detected varies with a predetermined period, the first error varies with the predetermined period, whereas the second error varies with a period ½ the predetermined period.