Encoder Signal Processing Circuit for Eccentricity Error Correction
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Solution Overview
Problem
In encoders with detectors mounted on a rotating shaft, eccentricity errors lead to 180° displacement issues, necessitating careful mounting to avoid dual solutions, complicating the detector installation process.
Innovation Solution
A signal processing circuit that calculates and corrects angular values from detectors on both sides of a rotating shaft by storing and applying an initial angular difference, ensuring the values become closer and preventing 180° differences, thus simplifying detector mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If detectors are mounted carefully to avoid 180° angular difference, then measurement precision is improved, but ease of manufacture deteriorates due to complex mounting requirements
Solution Approach 1:
The system performs preliminary action by calculating the initial angular difference between detectors during a reference period and storing this value for subsequent correction. This preliminary calculation and storage of the angular difference eliminates the need for careful manual mounting alignment, as the system automatically compensates for any mounting variations.
Solution Approach 2:
The system changes the parameter handling by introducing dynamic correction based on the stored initial angular difference. Instead of relying on precise physical mounting parameters, the system modifies the angular value parameters through automated correction calculations, allowing flexible mounting while maintaining measurement precision.
2Ease of manufacture
If detectors are mounted with flexible positioning, then ease of manufacture is improved, but measurement precision deteriorates due to potential 180° displacement
Solution Approach 1:
The system implements feedback by continuously monitoring the angular difference between detectors and automatically applying corrections based on the stored initial angular difference. This feedback mechanism ensures that even with flexible mounting positioning, the measurement precision is maintained by dynamically adjusting for any deviations.
Solution Approach 2:
The system replaces the mechanical alignment requirement with an automated computational correction system. Instead of relying on precise mechanical mounting positioning, the system uses electronic signal processing and angular difference correction to achieve accurate measurements, thereby substituting mechanical precision requirements with electronic compensation.
Data Source
AI summary
In an encoder which is equipped with two detectors arranged on both sides of a rotating shaft in order to eliminate an eccentricity error, the mounting of the detectors is facilitated by making provisions so as to not cause a problem in the calculating of an average even if the detectors happen to be so mounted that the difference between the angular values calculated from the outputs of the respective detectors becomes equal to 180°. In an initialization process after power on, the difference Δθ between the angular values θ1 and θ2 calculated from the signals output from the respective detectors is stored as an initial value. Position data θ is output by taking an average between θ3 and θ2, where θ3 is a value obtained by correcting θ1 by the initial difference Δθ.