Optical Position Sensor Cylinder with Unique Reference Mark Spacing
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Solution Overview
Problem
Existing position sensors for piston rods in cylinders require complex coding and long reference runs to detect the position accurately, especially when starting from a specific position, which complicates the measurement process.
Innovation Solution
A cylinder with a piston rod featuring a marking system using at least three reference marks with varying paired spacings, allowing for incremental position detection by measuring the distance between two adjacent reference marks, and optionally including distance marks for incremental position measurement, enabling shorter referencing distances and robust position sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single reference mark is used for incremental position measurement, then the position can be measured from a reference point, but a long reference run is required to detect the reference position
Solution Approach 1:
The patent divides the single reference mark into multiple reference marks (at least three) distributed along the piston rod. Each reference mark has a unique paired spacing relationship with other reference marks, allowing the sensor to identify the reference position more quickly by detecting the specific spacing pattern rather than traversing a long distance to find a single reference point.
2Measurement precision
If an absolute position code is used on the marking, then the position can be determined absolutely without reference runs, but the coding structure and sensor complexity increase
Solution Approach 1:
Instead of using complex absolute position codes, the patent changes the parameter being measured from absolute position encoding to relative spacing measurement. By measuring the distances between multiple reference marks with unique paired spacings, the system can determine absolute position through incremental measurement without requiring complex coding structures or sophisticated 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
This solution simplifies and robustly detects the position of the piston rod by reducing the referencing distance and complexity, allowing for accurate incremental measurements with minimal travel, and enables efficient determination of the piston rod's position using an optical position sensor.
Implementation Method 1
an optical position sensor which is directed towards a marking arranged on the piston rod
Data Source
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AI summary
Cylinder with a piston rod and an optical position sensor directed towards a mark arranged on the piston rod, wherein the position sensor is configured to incrementally detect the position of the piston rod starting from a reference mark, and the mark has at least three reference marks whose pairwise distances in the axial direction are each different from one another, wherein the pairwise distance between two adjacent reference marks is uniquely assigned to the positions of the two reference marks, and distance marks are provided between two reference marks for an incremental measurement of the distance between the two reference marks.