Code Disc Absolute Window Width and Encoder Resolution
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Solution Overview
Problem
The reliability of photoelectric encoders is reduced due to the narrowing of the absolute signal window as the number of incremental code channels increases, leading to instability and errors in signal output.
Innovation Solution
A code disc design with uniformly distributed incremental and absolute code channels, where the absolute window width is increased by configuring the coding mode and fixed grating to enhance PD photosensitivity and stability, allowing for a reduction in the number of code channels while maintaining encoder performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of incremental code channels increases to improve resolution, then the measurement precision is improved, but the absolute signal window becomes narrow resulting in reduced reliability
Solution Approach 1:
The code disc is segmented into distinct functional zones: incremental code channels for high-resolution measurement and absolute code channels for reliable absolute positioning. The incremental code channels are further segmented into multiple tracks (first, second, third incremental code channels) that can be independently configured. This segmentation allows the system to achieve high resolution through multiple incremental tracks while maintaining a separate, dedicated absolute signal path with sufficient window width for reliable detection.
2Measurement precision
If the number of incremental code channels increases to improve resolution, then the measurement precision is improved, but the absolute window width decreases leading to insufficient PD photosensitivity
Solution Approach 1:
The code disc structure separates incremental coding functions from absolute coding functions into distinct channels. The absolute code channels are allocated dedicated window areas that are independent of the incremental code channel density. This allows the PD array to receive sufficient light intensity for absolute position detection regardless of how many incremental code channels are configured for high-resolution measurement.
3Measurement precision
If the number of incremental code channels increases to improve resolution, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The code disc structure is designed with universal components that serve multiple functions. The fixed grating pattern serves both as the reference for incremental measurement and as the basis for absolute position encoding. The PD array structure can detect signals from both incremental and absolute code channels simultaneously. This multi-functionality reduces overall device complexity despite supporting multiple code channels for high resolution.
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 solution ensures improved stability and reliability of the absolute signal, increases PD photosensitivity, and facilitates miniaturization of the encoder by widening the absolute window, thereby overcoming the limitations of narrow window widths and instability in existing encoders.
Implementation Method 1
The photoelectric encoder is an angle measuring device that integrates light, machine and electricity, which converts optical signals into electrical signals through the mechanical structures and signal processing circuits
Data Source
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AI summary
Disclosed are a code disc and an encoder. The code disc includes a code channel component obtained by coding according to a set coding mode, and a fixed grating corresponding to the code channel component; the coding mode is configured to increase a width of an absolute window of the code channel component. By the solution of the disclosure, problems that the absolute signal window becomes narrower as the number of reticles of the incremental code channel increases and accordingly the reliability of the encoder is reduced are solved, thereby improving the reliability of the encoder.