Capacitive Rotary Encoder Arrays for High-Resolution Low-Power Sensing
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Solution Overview
Problem
Existing rotary encoders, such as those from Leine & Linde AB and rotary optical encoders, suffer from low resolution and reliability issues, making them unsuitable for precise motor control and flow meter applications, and they also consume higher power.
Innovation Solution
The development of capacitive-sensing rotary encoders with multiple circumferential capacitive sensor arrays that detect changes in capacitance as a conductor rotates, allowing for accurate determination of angular position and direction, and can be implemented as both absolute and incremental encoders with lower power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional rotary optical encoders are used, then angular position detection is achieved, but power consumption is high and reliability is low
Solution Approach 1:
The patent replaces traditional optical encoding mechanisms with a capacitive sensing system. Instead of using optical components that require light sources and detectors (consuming power and reducing reliability), the invention uses capacitive sensors that detect changes in capacitance caused by the rotation of a conductive element, thereby eliminating the need for complex optical systems and reducing power consumption while improving reliability
Solution Approach 2:
The patent changes the detection parameter from optical properties to electrical capacitance. By measuring capacitance variations as the conductive element rotates relative to the capacitive sensor arrays, the system achieves reliable position detection with lower power consumption, as capacitive sensing requires minimal energy compared to optical systems
2Measurement precision
If traditional rotary encoders are used, then rotation tracking is achieved, but resolution is low
Solution Approach 1:
The patent divides the capacitive sensing system into multiple independent sensor arrays arranged circumferentially around the rotation axis. Each array independently measures capacitance changes, and their combined outputs provide high-resolution angular position information. This segmentation allows for improved resolution while maintaining reliability through redundancy and error correction capabilities
3Measurement precision
If higher resolution detection is implemented, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent designs the capacitive sensor arrays and conductive elements to serve multiple functions simultaneously. The same structural components that define the encoder geometry also serve as the sensing elements, eliminating the need for separate sensing mechanisms and reducing overall device complexity while maintaining 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 capacitive-sensing rotary encoders provide high-resolution, reliable, and efficient angular position detection, improving motor control and flow meter accuracy while reducing power consumption compared to traditional rotary optical encoders.
Implementation Method 1
a rotary encoder including a plurality of circumferential capacitive sensor arrays, each of the plurality of capacitive sensor arrays having an output representing a binary bit of a rotary encoder output, the rotary encoder output changing as a conductor rotates responsive to a rotatable shaft of the motor relative to the rotary encoder
Data Source
AI summary
Example capacitive-sensing rotary encoders and methods are disclosed herein. An example apparatus includes a rotary encoder structured to be mounted to a motor, the rotary encoder including a plurality of circumferential capacitive sensor arrays, each of the plurality of capacitive sensor arrays having an output representing a binary bit of a rotary encoder output, the rotary encoder output changing as a conductor rotates responsive to a rotatable shaft of the motor relative to the rotary encoder.