Rotation Detection Device Pitch Error Correction
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Solution Overview
Problem
Existing rotation detection devices require additional sensors or encoders to correct errors in rotational position, increasing mounting space and costs, and struggle to accurately detect rotational speed and position without a reference sensor.
Innovation Solution
A rotation detection device that includes an encoder with cyclically arranged patterns, a sensor to generate pulse signals, a reference pattern storage unit to measure and store pitch errors, a phase difference detection unit to determine relative phase differences, and an error correction unit to correct pitch errors based on these differences, allowing for accurate rotational speed and position detection without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Z phase signal or additional sensor is provided to correct pitch errors, then measurement precision is improved, but device complexity and mounting space increase
Solution Approach 1:
The patent extracts the reference position information from a separate Z phase sensor and embeds it directly into the encoder disk pattern. By creating a unique reference pattern (such as a missing tooth or distinct magnetic pattern) on the encoder disk, the system eliminates the need for an additional reference sensor while maintaining the ability to identify rotational position and correct pitch errors.
Solution Approach 2:
The patent combines multiple functions into a single encoder disk: the regular scale patterns for rotational measurement and the reference pattern for position identification are integrated into one component. This merging eliminates the need for separate Z phase sensors and reduces system complexity while maintaining measurement precision.
2Measurement precision
If a Z phase signal is provided with high mounting accuracy, then measurement precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The reference pattern is pre-formed during the encoder disk manufacturing process rather than requiring precise field mounting. By incorporating the reference pattern as an integral part of the encoder disk structure (such as a missing tooth or pre-magnetized region), the system eliminates the need for high-precision mounting operations and allows for easier assembly while maintaining measurement accuracy.
3Measurement precision
If pitch errors are corrected using stored error patterns, then measurement precision is improved, but device complexity increases due to additional correction mechanisms
Solution Approach 1:
The system uses the encoder's own reference pattern to generate and apply correction data. By comparing the detected reference pattern position with the expected position, the system automatically calculates pitch errors and applies corrections without requiring external reference sensors or complex additional correction mechanisms.
Data Source
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AI summary
The rotation detection device includes: an encoder having to-be-detected patterns cyclically arranged in the circumferential direction; and a sensor configured to detect the to-be-detected patterns to generate pulses. The device further includes a reference pattern storage unit, a phase difference detection unit, and an error correction unit. The reference pattern storage unit measures pitch errors in the to-be-detected patterns prior to operation and stores the pitch errors as a reference pattern Pref. The phase difference detection unit determines a pitch error pattern Pm corresponding to one rotation of the to-be-detected patterns from rotation signals representing a plurality of rotations detected during operation, and performs comparison with a reference pattern Pref to determine a relative phase difference φ. Based on the phase difference φ obtained by the phase difference detection unit, the error correction unit corrects errors included in the rotation signals detected by the sensor.