Absolute Encoder Nonlinear Track Modulation
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Solution Overview
Problem
Existing absolute encoder systems face challenges in accurately determining the absolute angular position of a shaft without the need for an absolute reference marker, particularly in applications requiring precise and unlimited rotation.
Innovation Solution
A rotary encoder system comprising multiple tracks with nonlinearly modulated track elements and sensors positioned in quadrature relationships to detect the track elements, allowing for the computation of absolute angular position based on sensor signals without an absolute reference marker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional absolute encoder systems use an absolute reference marker to determine shaft position, then position determination is possible, but the system complexity increases and reliability decreases due to the additional marker requirement
Solution Approach 1:
The patent removes the absolute reference marker from the encoder system entirely. Instead of using a physical marker on the shaft, the system extracts position information solely from the modulation patterns of the track elements, which are read by sensors to compute absolute angular position without requiring any marker-based reference.
Solution Approach 2:
The patent introduces a computational intermediary (processor/evaluation unit) that calculates absolute position from sensor signals derived from nonlinearly modulated track elements. This computational mediator replaces the physical reference marker, transforming the system from marker-based physical reference to markerless computational reference.
2Measurement precision
If traditional encoder systems use linearly modulated track elements, then the structure is simple, but the measurement precision and resolution are insufficient for high-precision applications
Solution Approach 1:
The patent changes the modulation parameter of the track elements from linear to nonlinear. Specifically, the track elements are configured with nonlinear modulation patterns (such as sinusoidal or other curved modulation functions) that encode higher-resolution position information within the same physical track structure, thereby increasing measurement precision without adding more tracks or sensors.
3Measurement precision
If the encoder system uses multiple sensors to detect track elements, then measurement accuracy improves, but the device complexity and cost increase
Solution Approach 1:
The patent segments the position detection function across multiple tracks with different nonlinear modulation patterns, where each track is detected by dedicated sensors. This segmentation allows the system to achieve high measurement precision through combination of multiple modulated tracks while maintaining a manageable sensor count, as each sensor pair (one per track) contributes independently to the overall position calculation.
Data Source
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AI summary
Systems and methods for implementing an absolute encoder are disclosed. A system can include a plurality of tracks (12, 14), each having a plurality of track elements (20, 22). Track elements (22) for at least one of the tracks (14) are configured with a nonlinear modulation, such that an absolute position can be determined without requiring a reference marker.