Rotatable Plate Encoder with Reversed Patterns for Dust Error Correction
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Solution Overview
Problem
Existing encoders for detecting rotation shafts in motors face accuracy issues due to dust or foreign substances adhering to the patterns, leading to erroneous detection and decreased accuracy, as they fail to effectively notice and correct such errors.
Innovation Solution
The encoder employs a rotatable plate with alternating first and second patterns, where the second pattern reverses the output values of the light receiving elements, allowing for the detection of abnormalities and enabling correction of erroneous data, thereby preventing decreases in detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pattern is used for rotation detection, then the device structure is simple, but detection accuracy decreases when dust or foreign substances adhere to the pattern
Solution Approach 1:
The pattern is divided into multiple independent patterns (first pattern and second pattern) with different arrangements of light-guidable and non-light-guidable portions. Each pattern can independently detect rotation, and their outputs are compared to identify and correct errors caused by dust or foreign substances, thereby maintaining high detection accuracy without excessive complexity
Solution Approach 2:
Different regions of the pattern have different light-guiding properties (some portions guide light, others do not), and these properties are distributed differently across multiple patterns. This local variation allows the system to detect abnormalities when dust adheres to specific regions, as the abnormal detection can be identified by comparing outputs from patterns with different local configurations
2Measurement precision
If multiple patterns with reversed arrangements are used, then detection accuracy is maintained even with dust or foreign substances, but the device complexity increases
Solution Approach 1:
The second pattern uses a reversed arrangement of light-guidable and non-light-guidable portions compared to the first pattern. When the rotatable plate rotates, the light receiving elements produce output values that are reversed between the two patterns. This inversion allows error detection and correction by comparing the reversed outputs, maintaining high accuracy while keeping the additional complexity manageable through systematic design
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
This configuration allows for the detection of abnormalities and correction of errors, ensuring accurate rotation detection and preventing decreases in detection accuracy even when foreign substances adhere to the patterns.
Implementation Method 1
a light emission unit configured to emit light to the first pattern and the second pattern
Implementation Method 2
a light receiving unit configured to receive light emitted from the light emission unit and passing through the first pattern and light emitted from the light emission unit and passing through the second pattern
Implementation Method 3
The first unit regions are configured to guide the light emitted from the light emission unit to the light receiving unit
Implementation Method 4
The second unit regions are configured not to guide the light emitted from the light emission unit to the light receiving unit
Data Source
AI summary
An encoder includes rotatable plate including first and second patterns, light emission unit, and light receiving unit. The first pattern includes first and second unit regions. The first unit regions guide the light from light emission unit to the light receiving unit. The second unit regions are configured not to guide light from the light emission unit to the light receiving unit. The second pattern includes first and second unit regions. The first unit regions of the second pattern guide light from light emission unit to the light receiving unit. The second unit regions of the second pattern are configured not to guide light from the light emission unit to the light receiving unit. The first and second unit regions of the first pattern are reverse to the first and second unit regions of the second pattern in a direction perpendicular to a rotation direction of the rotatable plate.