Elevator Bounce Detection to Prevent False Emergency Braking
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Solution Overview
Problem
Elevator systems often experience unnecessary emergency braking due to vertical bouncing caused by passengers or items, which can trigger false over-speed conditions and result in unneeded stoppages, disrupting service.
Innovation Solution
A vertical bounce detection system that uses sensors, a processing system, and a memory system to determine bounce energy levels and apply a speed reduction when the bounce energy exceeds a threshold, thereby preventing unnecessary emergency braking. This system includes a safety actuator that can apply a braking force and restore normal speed when conditions are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the emergency braking system is activated to ensure safety, then the reliability of the elevator system is improved, but unnecessary stoppages occur due to false over-speed conditions caused by vertical bounce
Solution Approach 1:
A bounce detection system acts as an intermediary between the motion sensors and the emergency braking system. This intermediary layer analyzes sensor data to distinguish between harmful over-speed conditions requiring emergency braking and benign bounce conditions that should not trigger safety mechanisms, thereby preventing false positives while maintaining actual safety
Solution Approach 2:
The system implements feedback by continuously monitoring elevator car motion through sensors and using this information to modulate the emergency braking system's activation. The bounce detection algorithm processes ongoing sensor data, compares it against threshold criteria, and provides real-time feedback to control whether the emergency brake should engage, creating a closed-loop safety system that reduces false activations
2Reliability
If sensors and processing systems are added to detect vertical bounce, then false emergency braking is reduced, but the device complexity increases
Solution Approach 1:
The bounce detection system is designed to be integrated within the existing elevator control architecture, where the processing system can utilize existing sensors for multiple purposes - both for normal operation control and for bounce detection. This multi-functional approach allows the system to gain enhanced safety capabilities without requiring entirely separate dedicated hardware systems
Solution Approach 2:
The system uses the elevator's existing motion sensors and processing capabilities to perform bounce detection autonomously. The processing system analyzes sensor data using bounce detection algorithms and automatically determines whether emergency braking should be activated, eliminating the need for external manual monitoring or additional complex diagnostic equipment
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
Effectively detects vertical bouncing and reduces elevator speed to prevent unnecessary emergency braking, ensuring smooth operation and reducing the frequency of unneeded stops, thereby enhancing service reliability.
Implementation Method 1
at least one sensor operable to detect vertical movement of an elevator car in a hoistway
Data Source
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AI summary
A vertical bounce detection system (200) of an elevator system includes at least one sensor (204) operable to detect vertical movement of an elevator car (103) in a hoistway. The vertical bounce detection system (200) also includes a processing system (206) communicatively coupled to the at least one sensor (204) and a memory system (208) having instructions stored thereon that, when executed by the processing system (206), cause the vertical bounce detection system (200) to determine a bounce energy level of the elevator car (103) based on sensor data from the at least one sensor (204). The instructions further cause the vertical bounce detection system (200) to compare the bounce energy level to a bounce condition threshold. A speed reduction of the elevator car (103) is commanded to continue movement of the elevator car (103) at a reduced speed based on determining that the bounce energy level exceeds the bounce condition threshold.