Rotary Encoder Additive Magnetic Features
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Solution Overview
Problem
Magnetic encoder systems face challenges in achieving high resolution and accuracy in detecting the angular position and motion of a rotatable shaft, particularly in environments with shock, vibration, and contamination, where traditional methods may fail to provide reliable and precise data.
Innovation Solution
A magnetic rotary encoder structure featuring linear, areal, and other magnetic features distributed over a planar and cylindrical surface, formed through additive manufacturing, which allows for high-resolution detection using induction coil sensors, enabling precise angular position and motion data retrieval without the need for additional activation sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional magnetic encoder methods are used, then the system is simpler and easier to manufacture, but the resolution and accuracy of angular position detection are insufficient
Solution Approach 1:
The patent transitions from traditional one-dimensional linear scales to two-dimensional areal scales with radial and circumferential variations. The magnetic features are distributed across a radial extent and circumferential angle, creating a multi-dimensional encoding pattern that significantly increases resolution without proportionally increasing device complexity
Solution Approach 2:
The encoder scale is divided into multiple discrete magnetic features distributed radially and circumferentially. Each feature acts as an independent encoding element, allowing the system to achieve high resolution through the collective pattern of segmented features rather than requiring a single continuous high-precision scale
2Measurement precision
If higher resolution magnetic features are implemented, then detection accuracy improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent varies multiple parameters of the magnetic features including radial position, circumferential angle, radius, and width. By encoding information across multiple varying parameters rather than relying on single high-precision dimensional features, the system achieves high detection accuracy while reducing the stringency of manufacturing precision requirements for individual features
3Measurement precision
If optical encoder systems are used, then high resolution can be achieved, but additional activation sources are required which reduce reliability in harsh environments
Solution Approach 1:
The patent replaces optical detection systems with magnetic field-based detection. Magnetic fields penetrate contaminants and are unaffected by shock and vibration in the same way optical systems are, eliminating the need for fragile light sources and photodetectors while maintaining high resolution capability through the magnetic feature patterns
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 enhances the resolution and accuracy of magnetic encoder systems, providing reliable data in harsh environments by utilizing additive manufacturing to create precise magnetic features and induction coil sensors, suitable for both absolute and relative position sensing.
Implementation Method 1
When a magnetic rotary encoder structure rotates relative to a fixed sensor, the magnetic field of the encoder is detected by the sensor and an output signal is generated that characterizes the position of the encoder
Data Source
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AI summary
A rotary encoder may include a magnetic encoder disc having a plurality of magnetic features added to the disc by additive manufacturing distributed over a surface of the encoder disc, wherein the disc is configured for attachment to the end of a rotatable shaft, or a cylindrical metallic encoding feature having a plurality of magnetic features added to the cylindrical encoder by additive manufacturing distributed over the surface of the cylindrical encoding feature, wherein the encoding feature is capable of attachment to an outer diameter of the rotatable shaft. The encoder additionally includes a magnetic sensor positioned adjacent to the end of the rotatable shaft to detect magnetic signals from the magnetic features on the disc and/or positioned over the surface of the rotatable shaft to detect magnetic signals from the magnetic features on the encoding feature.