Elevator Hoistway Safety Detection Using Multi-Sensor Signal Comparison
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Solution Overview
Problem
In modern elevator systems with low pits and overheads, there is a need for a reliable safety system to detect people within the hoistway to prevent them from being hit or squeezed by the moving elevator car, especially during maintenance or repair, as existing systems are not adequately effective in ensuring safety.
Innovation Solution
The implementation of an elevator safety system comprising at least two sensors, a transformation unit, a comparison unit, and a detection unit, which monitor the hoistway, transform signals to a common direction, compare them for malfunctions, and generate alarm signals if people or items are detected, thereby stopping the elevator operation to prevent accidents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If at least two sensors are employed to monitor the hoistway, then the reliability of person detection is improved, but the device complexity increases
Solution Approach 1:
The patent uses multiple sensors (at least two) to create redundant copies of the monitoring function. Each sensor independently monitors the hoistway, and their signals are compared to detect persons. This copying approach ensures that if one sensor fails or gives false readings, the other sensors can compensate, thereby improving detection reliability while managing complexity through standardized sensor implementations.
Solution Approach 2:
The system implements feedback by continuously comparing signals from multiple sensors. The evaluation unit analyzes the monitoring signals in real-time, and when a person is detected, the system provides feedback by generating an alarm signal and stopping elevator operation. This closed-loop feedback mechanism enhances reliability by continuously verifying sensor data and immediately responding to detected hazards.
2Measurement precision
If sensor signals are transformed to a common direction of vision, then the measurement precision of person detection is improved, but the device complexity increases
Solution Approach 1:
The patent introduces a transformation unit as an intermediary component that converts monitoring signals from different sensor orientations into a common direction of vision. This intermediary processing step enables precise person detection by standardizing the coordinate systems of multiple sensors, allowing accurate spatial localization of detected persons while isolating the complexity of coordinate transformations from the core detection logic.
3Reliability
If the elevator system stops operation when a failure signal or alarm signal is generated, then the safety of the elevator system is improved, but the productivity decreases
Solution Approach 1:
The system applies preliminary anti-action by proactively stopping elevator operation before an accident can occur. When the detection unit identifies a person in the hoistway or when the comparison unit detects sensor malfunction, the system immediately generates alarm or failure signals that trigger operation cessation. This preemptive safety measure prevents potential harm to persons in the hoistway, prioritizing safety over continuous operation and productivity.
Data Source
AI summary
An elevator safety system includes: at least two sensors, each of the sensors being configured for monitoring at least a portion of a hoistway of an elevator system and providing monitoring signals; a transformation unit which is configured for transforming the monitoring signals provided by at least one of the sensors and producing transformed signals corresponding to a common direction of vision; a comparison unit which is configured for comparing the at least two transformed signals and for generating a failure signal if a difference between the at least two transformed signals exceeds a predetermined threshold; and a detection unit, which is configured for detecting a person or undesired item in at least one of the two transformed signals and for generating an alarm signal if a person or undesired item is detected.