Elevator Door Light Grid Reversal Detection by Intensity Alternation
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Solution Overview
Problem
Existing light grids for elevator car doors lack precision in detecting door reversals and defects, such as a dirty door, due to inadequate intensity value evaluation and signal recognition.
Innovation Solution
A light grid system with a control device that evaluates intensity values in distinct ranges and recognizes alternation phases to accurately detect door reversals and defects by defining specific intensity limits and alternation patterns, allowing for precise door state evaluation and wireless signal transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing light grids use simple object detection without intensity range evaluation, then the device complexity is low, but the measurement precision for door reversals and defects is insufficient
Solution Approach 1:
The invention divides the radiation intensity values into three distinct ranges (low, medium, high) with predetermined limit values, transforming the continuous intensity parameter into discrete categories. This enables the detection system to identify alternation phases between low and medium ranges, which indicates door reversals, while maintaining a manageable device complexity through systematic parameter evaluation.
Solution Approach 2:
The control device continuously evaluates the intensity values from receiver elements and compares them against the predetermined limit values to detect alternation phases. This feedback mechanism allows the system to recognize door reversals by identifying patterns where intensity alternates between low and medium ranges, providing precise detection without requiring overly complex hardware.
2Measurement precision
If the control device evaluates intensity values with multiple ranges and alternation phase recognition, then the detection precision improves, but the loss of time for processing increases
Solution Approach 1:
The invention focuses on detecting periodic alternation phases between low and medium intensity ranges, which correspond to the periodic motion of door reversals. By recognizing these periodic patterns rather than analyzing every single intensity change, the system achieves high detection precision while minimizing processing time through efficient pattern recognition.
Solution Approach 2:
The control device evaluates only the necessary intensity range transitions (low to medium and back to low) that indicate door reversals, rather than analyzing all possible intensity variations. This partial evaluation approach maintains high detection precision for critical events while reducing unnecessary processing time for non-critical intensity fluctuations.
3Reliability
If the light grid uses only basic object detection, then the device complexity is low, but the reliability for recognizing defective or dirty doors is insufficient
Solution Approach 1:
The invention uses intensity range parameter changes to distinguish between normal door operation and abnormal conditions. By monitoring alternation phases between low and medium intensity ranges and comparing them against predetermined limit values, the system reliably detects door reversals, defective doors, and dirty surfaces, enhancing reliability without requiring complex additional sensors or mechanisms.
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 precise detection of door reversals and defects, facilitating improved door operation and maintenance by providing detailed evaluation and wireless communication of door states.
Implementation Method 1
at least one transmitter element on a transmitter strip, which emit radiation with a specific intensity
Implementation Method 2
at least one receiver element on a receiver strip, which receive the radiation of an assigned transmitter element, and comprising a control device for evaluating the receiver elements
Data Source
AI summary
A light grid for mounting on an elevator car door for object detection and for determining periodic door movements, including transmitter elements that emits radiation with a specific intensity, receiver elements for receiving the radiation from an assigned transmitter element, and a control device for evaluating the receiver elements in regard to interruption of the radiation coming from an assigned transmitter element and for outputting a signal for object recognition upon interruption. At least one receiver element is configured to output an intensity value for the received radiation. The control device evaluates the intensity value and distinguishes separate high, medium and low intensity value ranges with high, medium and low intensity values, and performs an alternation phase with at least one alternating from the low via the medium to the low intensity value range and to output a signal in the event of an alternation phase having been recognized.