Valve Rotary Encoder With Non-Repeating Optical Position Pattern
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Solution Overview
Problem
Existing position sensors for valves, such as micro-mechanical switches and optical absolute rotary encoders, are bulky, unreliable, and complex, and struggle with accuracy due to mechanical wear and external forces, and require additional sensors for absolute positioning.
Innovation Solution
A rotatable code plate with a non-repeating angle-dependent pattern and an optical detector module that processes time-varying signals to determine the absolute position of the valve, allowing for compact and accurate position sensing without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If micro-mechanical switches are used for position sensing, then the valve position can be determined, but the sensor becomes bulky and unreliable due to mechanical wear and external forces
Solution Approach 1:
The patent replaces micro-mechanical switches with an optical detection system consisting of a code plate with optical patterns and optical detectors. This substitution eliminates mechanical wear and improves reliability by using optical fields instead of mechanical contacts to determine valve position.
Solution Approach 2:
The patent uses optical patterns on a code plate that represent positional information. The optical detectors read these optical copies of position data rather than directly measuring mechanical displacement, enabling non-contact position sensing.
2Measurement precision
If optical absolute rotary encoders are used to determine shaft position, then position accuracy is improved, but the encoder becomes complex and relatively large
Solution Approach 1:
The code plate is divided into multiple concentric circular arcs with distinct optical patterns. Each arc segment provides positional information for a specific angular range, allowing the system to determine absolute position by reading patterns from multiple segmented regions simultaneously.
Solution Approach 2:
The patent uses multiple concentric circular arcs arranged radially to encode positional information. By adding the radial dimension with multiple arcs, the system can determine absolute position without requiring a large single-dimensional encoder structure.
3Device complexity
If a non-repeating angle-dependent pattern is used on the code plate, then absolute position can be determined without additional sensors, but the pattern design becomes more complex
Solution Approach 1:
The code plate employs asymmetric optical patterns where at least two sectoral elements in non-adjacent sectors are identical, but the overall pattern is non-repeating over a full rotation. This asymmetric design enables absolute position determination because each angular position produces a unique optical signature that can be identified without additional reference sensors.
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
Enables simpler, more compact position sensing with high accuracy and reduced mechanical complexity, capable of distinguishing multiple valve states using fewer optical detectors, and minimizing electromagnetic interference.
Implementation Method 1
each optical detector is aligned with a respective arc of said set of one or more concentric circular arcs around the rotatable code plate and is configured to receive light passing through a void of the code plate when the code plate is in any of a first set of angular positions and to be blocked by the code plate from receiving light through the code plate when the code plate is in any of a second set of angular positions
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
A rotary encoder (7) for a valve (1) comprises a rotatable code plate (8) and an optical detector module (11) comprising one or more optical detectors (22, 23). The code plate defines a set of voids (30, 31) arranged along a set of one or more concentric circular arcs about an axis of rotation. The voids define an angle-dependent pattern over the set of arcs, the pattern comprising a plurality of distinct sectoral elements (A-O, X). At least two of the sectoral elements, located in non-adjacent sectors of the code plate, are identical, but the pattern is non-repeating over a single full rotation of the code plate about the axis. Each optical detector is aligned with a respective concentric circular arc of the code plate. A controller (6) processes time-varying output signals from the optical detectors to determine successive positions of the rotatable code plate.