Light Grid Speed Measurement via Effective Beam Bundles
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Solution Overview
Problem
Existing light grids are unable to accurately measure the speed of objects moving perpendicularly to the protective field and determine their distance from the light source.
Innovation Solution
A light grid with 'effective' light beam bundles, where partial shadowing causes measurable intensity changes, and an evaluation unit determines object speed and distance by analyzing the crossing points of switching lines, allowing for precise localization and speed measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two light grids are arranged one behind the other to measure speed of objects moving perpendicularly, then speed measurement becomes possible, but device complexity increases
Solution Approach 1:
The patent divides a single light grid into multiple independently controllable light transmitter units, each capable of emitting light sequences with different temporal patterns. This segmentation allows the system to simulate multiple light grids' functionality while using only one physical grid, thereby enabling speed measurement of perpendicularly moving objects without increasing device complexity
Solution Approach 2:
The light transmitter units emit light in periodic sequences with different frequencies and timing patterns. By modulating the light emission periodically and analyzing the temporal patterns of interruptions, the system can determine the speed of objects moving perpendicularly to the protective field, achieving speed measurement capability without requiring multiple physical light grids
2Measurement precision
If conventional light beams are used, then the system is simple, but partial shadowing cannot be detected and thus speed and distance cannot be determined
Solution Approach 1:
The patent creates effective light beam bundles with specific spatial characteristics by controlling individual light transmitters to emit light in directed sequences. These bundles have defined spatial distribution patterns that enable detection of partial shadowing effects, allowing the system to measure both speed and distance of objects without requiring complex additional hardware
Solution Approach 2:
The light transmitter units dynamically adjust their emission patterns, timing, and sequencing to create effective light beam bundles with varying spatial characteristics. This dynamic control allows the system to optimize beam configuration for different measurement scenarios, enabling partial shadowing detection while maintaining system simplicity
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 accurate speed measurement and localization of objects moving perpendicularly to the light grid, with the ability to determine distance from the light transmitters, using measurable intensity changes and switching lines.
Implementation Method 1
a light emitting unit with a plurality of light emitters... each pair of assigned light emitters and light receivers defining between them an effective light beam bundle
Implementation Method 2
partial shadowing of this effective light beam causes a measurable intensity change corresponding to the partial shadowing in the associated light receiver
Implementation Method 3
a light receiving unit with a plurality of light receivers, each of the light receivers being assigned to one of the light emitters and each light receiver providing received signals dependent on the incident light intensity
Data Source
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AI summary
The invention relates to a light grid for determining the velocity of an object conveyed through the protective field of the light grid, wherein the conveying direction is perpendicular to the protective field. A light receiver determines the temporal profile of the intensity as the object traverses a beam of light between the transmitter and receiver. The velocity can be determined from the change in intensity, the corresponding time, and the extent of the beam. In an alternative embodiment, two beams of light are used. For each beam, two time points are determined at which a defined fraction of the intensity is recorded during the passage. The beams are designed such that the quotient of the difference between the two time points for each beam has a different, known value at each distance from the light source.This allows both the distance of the object from the light source and its speed to be determined.