Motorized Door Detection Array for Impact Force Control
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Solution Overview
Problem
Motorized doors, particularly fast doors, face challenges in reducing impact force with obstacles within their closing trajectory, as existing detection systems often fail to distinguish between accidental obstacles and the final closing position, leading to potential harm and non-compliance with safety norms like EN12453.
Innovation Solution
A motorized door equipped with an array of detection cells along the leading edge, communicating with a CPU to differentiate between accidental obstacles and the final closing position by measuring the proportion of cells detecting an object within a safety distance, allowing for controlled speed reduction or reversal to prevent impacts exceeding 400 N.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If detection cells are used to detect obstacles before impact, then safety is improved, but false alarms occur when detecting the distal transverse edge
Solution Approach 1:
The detection system is segmented into multiple detection cells arranged along the closing trajectory. Each cell independently detects objects, and the CPU analyzes the spatial distribution pattern of detections to distinguish between accidental obstacles (detected by few cells) and the distal transverse edge (detected by many cells), thereby eliminating false alarms while maintaining safety
Solution Approach 2:
The system uses an array of multiple detection cells (excessive detection coverage) along the entire closing trajectory. By detecting at multiple positions and analyzing the proportion of cells detecting an object, the system can partially identify the nature of the detected object, distinguishing between true obstacles and the normal closing edge
2Force
If the leading edge is equipped with damping elements, then impact force is reduced, but the force reduction is insufficient to meet EN12453 requirements
Solution Approach 1:
The system performs preliminary detection of obstacles before the leading edge reaches them using multiple detection cells. The CPU calculates the distance to detected objects and triggers preventive actions (stopping or reversing the shutter) before impact occurs, eliminating the need for relying solely on passive damping elements that provide insufficient force reduction
3Object-affected harmful factors
If contactless detection cells are used to detect obstacles before impact, then injury prevention is improved, but the system cannot distinguish between obstacles and the final closing position
Solution Approach 1:
The system adds a spatial distribution dimension to obstacle detection by arranging multiple detection cells along the closing trajectory. By analyzing not just whether an object is detected but also how many cells detect it and their spatial distribution, the system can distinguish between accidental obstacles (localized detection) and the distal transverse edge (distributed detection across multiple cells), enabling accurate object identification without contact
Data Source
AI summary
The present invention concerns a motorized door comprising an array of n detection cells distributed along the length of the leading edge, capable of detecting the presence and distance, Δx, from said detection cell of a body positioned between said detection cell and a distal transverse edge. The detection cells are coupled to a CPU which triggers different actions during the closing of the shutter, depending on the proportion, P=n1/n of the number, n1, of detection cells identifying the presence of a body at a same time located at a distance, Δx≤Δxs, wherein Δxs is a predefined safety distance. (a) if P≤Ps, wherein Ps is a predefined safety proportion, the detected body is considered as an accidental obstacle and the CPU is programmed to instantly stop the movement of the shutter; (b) if P>Ps, the CPU considers that the detected body is a distal transverse edge defining the end of the closure run, and orders to decrease the closing speed of the shutter until the leading edge contacts the distal transverse edge.