Resolver Angle Detection Error Correction via Fourier Transform
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Solution Overview
Problem
Resolver devices face challenges in accurately correcting detection errors, leading to low precision in angle detection due to imbalance and mutual interference of windings, which is cumbersome and not suitable for real-time high-speed applications, especially in general-purpose servo motors and servo amplifiers.
Innovation Solution
The method involves applying a Fourier transform to analyze the frequency components of the detection angle signal, identifying reproducible error components, and using these to generate an error waveform signal for correcting the detected angle, allowing for precise error calculation and correction in real-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional table-based error correction methods are used, then detection precision is improved, but device complexity and processing time increase, making it unsuitable for real-time high-speed applications
Solution Approach 1:
The patent transforms the error correction approach from spatial domain (table-based) to frequency domain (spectral analysis). By changing the parameter representation from discrete angle-error pairs to frequency components, the system achieves real-time correction without complex lookup tables. The Fourier transform converts the error waveform into frequency components that can be processed efficiently.
Solution Approach 2:
The patent replaces the mechanical/table-based correction system with a signal processing system using Fourier transform. Instead of storing and searching large correction tables, the system uses spectral analysis to identify and correct error components, significantly reducing computational complexity and enabling real-time operation.
2Measurement precision
If individual resolver calibration is performed for each device, then detection precision is improved, but manufacturing time and cost increase
Solution Approach 1:
The patent enables resolvers to self-correct their errors through spectral analysis of their own output signals. Each resolver automatically identifies its unique error waveform characteristics and generates appropriate correction signals without requiring external calibration equipment or manual adjustment, significantly streamlining the manufacturing process.
Solution Approach 2:
The system performs error characterization and correction setup automatically during the initial operation phase. By analyzing the error waveform early and establishing the correction parameters beforehand, the system eliminates the need for time-consuming individual calibration procedures while maintaining high detection precision.
3Measurement precision
If Fourier transform is applied to velocity signal for error analysis, then error correction accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent extracts only the relevant frequency components from the velocity signal that correspond to resolver error characteristics. By focusing on specific spectral components rather than processing the entire signal spectrum, the system achieves accurate error correction while minimizing processing complexity and computational load.
Data Source
AI summary
A resolver apparatus having a high detection precision detecting angle signals from signals detected at a resolver (7) and detecting a velocity signal from the detected angle signals. Utilizing the fact that an error waveform of a resolver is comprised of predetermined n-th order components inherent to the resolver and has reproducibility, an angle error estimator (13) applies a frequency transform, for example, a Fourier transform, to high frequency components of velocity signal including error generated from detected angle signals including error to calculate a magnitude of error for each of a plurality of divided components and combining the calculated errors to reproduce the detected error and generate an error waveform signal. An angle signal correction circuit (14) uses this error waveform signal to correct an angle signal including error detected at the resolver.