Optical Encoder Code Disk Error Correction via Manchester Gray Coding
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Solution Overview
Problem
Optical absolute rotary encoders face challenges in maintaining positioning accuracy due to oil stains on the code disk, which can cause identification failures and false signal outputs, leading to potential processing dangers in industrial applications.
Innovation Solution
An optical absolute rotary encoder system with a code disk divided into sectors using Manchester and Gray coding, combined with a sensing circuit and photosensor arrays for error detection and correction, where the system determines and corrects errors in encoded values to ensure accurate positioning, employing column-skipping and interlaced encoding to reduce the impact of oil stains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the code disk is used for positioning in industrial environments, then positioning accuracy is required, but oil stains cause identification failures and false signals
Solution Approach 1:
The code disk is divided into multiple sectors with each sector containing code pieces arranged in radial directions. This segmentation allows the system to read multiple discrete code positions, enabling error detection and correction capabilities that maintain reliability even when some sectors are stained with oil.
Solution Approach 2:
The patent employs Manchester coding and Gray coding schemes for the code pieces, which change the parameter representation of positional information. These coding methods provide inherent error detection and correction capabilities, allowing the system to distinguish valid code patterns from those distorted by oil stains, thus maintaining signal accuracy despite environmental contamination.
2Measurement precision
If higher positioning accuracy is achieved by reducing positioning width, then measurement precision improves, but the code disk becomes more susceptible to oil stain interference
Solution Approach 1:
By dividing the code disk into multiple sectors with discrete code pieces, the system can distribute the positioning information across multiple locations. This segmentation reduces the impact of oil stains on any single location, allowing the system to maintain high positioning accuracy even when some sectors are contaminated.
Solution Approach 2:
The patent implements error detection and correction mechanisms that provide feedback on the quality of code recognition. When oil stains cause identification failures, the system can detect these errors through the coded structure and correct them, ensuring that positioning accuracy is maintained despite the presence of harmful factors like oil stains.
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 detects and corrects errors caused by oil stains, maintaining accurate positioning and reducing the risk of false outputs, thereby enhancing the reliability and robustness of the encoder in industrial settings.
Implementation Method 1
a light source device configured to generate a light beam; a code disk configured to illuminated by the light source device and a part of the light beam penetrating the code disk; an optical detector configured to receive the part of the light beam penetrating the code disk
Implementation Method 2
a first detecting area comprising a plurality of first photosensor blocks arranged into two photosensor arrays along a first direction; a second detecting area comprising a plurality of second photosensor blocks
Data Source
AI summary
A code disk is adapted to an optical absolute rotary encoder. The code disk is divided into a plurality of columns, with the plurality of columns disposed in a circumferential direction around a center position and respectively extending in a plurality of radial directions. The code disk comprises a plurality of disk sectors sequentially disposed in the circumferential direction around the center position, wherein each of the disk sectors comprises a plurality of code pieces, each of the code pieces comprises an encoded value, each of the encoded values comprises a plurality of bits adopting Manchester code, these bits are arranged in one of the radial directions, and the encoded values of two of the disk sectors are arranged as Gray code.