Elevator Speed Control for Abnormal Vertical Motion
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Solution Overview
Problem
Modern elevators experience unscheduled stops due to abnormal conditions like earthquakes, ship sways, or passenger movements, which can lead to inefficiency and inconvenience, as existing safety mechanisms trigger emergency braking or gear braking, even when the speed limit is momentarily exceeded during high-speed phases.
Innovation Solution
A method and system for controlling elevator speed by monitoring vertical speed and acceleration data to adjust the target speed during runs, reducing the likelihood of exceeding safety limits by lowering the speed setting if predetermined criteria are met, thereby minimizing unscheduled stops without compromising safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the elevator car operates at maximum constant target speed to provide quick transportation, then productivity is improved, but reliability deteriorates due to momentary exceeding of safety limits during abnormal conditions causing unscheduled stops
Solution Approach 1:
The patent applies dynamics by making the target speed adjustable rather than fixed. The control unit dynamically modifies the constant target speed based on real-time monitoring of car speed and comparison with safety limits. During abnormal conditions when momentary speed excursions occur, the system reduces the target speed to prevent triggering safety mechanisms, thereby maintaining operation continuity while still providing efficient transportation.
2Object-affected harmful factors
If safety limits are set to trigger immediate stopping when exceeded, then safety is improved, but productivity deteriorates due to unscheduled stops during abnormal conditions
Solution Approach 1:
The patent applies preliminary anti-action by proactively reducing the target speed before the car speed can exceed the safety limit and trigger an emergency stop. The control unit continuously monitors the relationship between car speed and safety limits, and when it detects that the car speed is approaching or may exceed the limit during abnormal conditions, it preemptively lowers the target speed. This prevents the harmful effect of unscheduled stops while maintaining safety.
3Productivity
If the constant target speed is maximized for quick transportation, then productivity is improved, but ease of operation deteriorates due to inconvenience caused by unscheduled stops
Solution Approach 1:
The patent applies feedback by implementing a closed-loop control system where the control unit continuously monitors the elevator car's speed and compares it with the safety limit. Based on this feedback, the system automatically adjusts the constant target speed. When the monitoring indicates that the car speed may exceed the safety limit during abnormal conditions, the feedback loop triggers a reduction in target speed, preventing unscheduled stops and maintaining passenger convenience while still achieving efficient transportation.
Data Source
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Figure 3~4
AI summary
The invention relates to a method for controlling an elevator, the method comprising controlling the speed of a vertically moving elevator car (1) during its run from a starting landing (2) to a destination landing (3) according to speed settings, the speed settings defining a constant target speed for the elevator car (1). The method comprises - obtaining measurement data of the ongoing run, which measurement data describes vertical speed and/or vertical acceleration of the vertically moving elevator car (1), - determining whether the measurement data meets one or more predetermined criteria indicating unintended vertical speed and/or unintended vertical acceleration, and - changing the speed settings of the current run by lowering the constant target speed from a first constant target speed (C1) to a second constant target speed (C2) if the measurement data meets said one or more predetermined criteria, - continuing the run without intermediate stops to said destination landing (3). The invention also relates to an elevator implementing said method.