TOF Camera Rope Sway Detection in Elevator Hoistways
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Solution Overview
Problem
Existing elevator systems in high-rise buildings face challenges in accurately detecting abnormal rope sway conditions due to building vibrations, especially in dark environments, where conventional camera systems struggle to monitor long ropes and maintain accurate tension control.
Innovation Solution
The implementation of a TOF camera system installed at different heights in the hoistway to monitor the governor rope, capturing image and distance data to estimate the maximum amplitude of rope sway, with a rope sway detector transmitting control signals to the elevator controller based on threshold values to manage elevator operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple cameras are installed to monitor all elevator ropes, then detection accuracy improves, but device complexity increases
Solution Approach 1:
The patent extracts the detection function from multiple cameras to a single camera system. By installing one camera at an intermediate position that can capture images of multiple ropes simultaneously, the system achieves comprehensive monitoring without the complexity of multiple camera installations, thereby reducing device complexity while maintaining detection accuracy
Solution Approach 2:
The single camera installed at the intermediate position serves multiple functions: it monitors multiple elevator ropes simultaneously, captures images at different angles, and detects abnormalities across the entire rope system. This multi-functional approach replaces what would traditionally require multiple specialized cameras, simplifying the overall system
2Device complexity
If cameras are installed at intermediate position, then device complexity reduces, but measurement precision deteriorates due to limited monitoring range
Solution Approach 1:
The patent positions the camera at an intermediate location that provides a multi-dimensional view of the rope system. By capturing images from this strategic position, the camera can monitor ropes extending in different directions and at various distances, effectively expanding the monitoring coverage beyond what a single-point measurement would provide
3Device complexity
If conventional cameras are used in dark environments, then device complexity remains simple, but measurement precision deteriorates
Solution Approach 1:
The patent introduces an auxiliary light source as an intermediary element to enable the camera to function in dark environments. This additional component allows the camera to capture clear images of the ropes regardless of ambient lighting conditions, effectively eliminating the limitation of dark hoistways without requiring a complete redesign of the detection system
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 enables accurate detection of abnormal conditions and effective control of elevator operations, reducing the complexity of the detection system and improving safety by using fewer cameras and eliminating the need to monitor multiple ropes, while maintaining accurate tension control.
Implementation Method 1
Rope sway detector with time-of-flight (TOF)-camera
Data Source
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AI summary
An abnormal condition detection device of an elevator related to building sway includes a plurality of TOF cameras (15) each disposed at different heights in a hoistway and configured to monitor rope sway of a governor rope (10a, 10b) and capture an image of the governor rope at each height of the TOF cameras, and includes a rope sway detector (13) connected to the TOF cameras (15) for detecting rope sway of the governor rope and transmitting an abnormal condition detection signal to an elevator controller.