Elevator Rope Sway Prediction Using Building Acceleration Data
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Solution Overview
Problem
Existing elevator systems in high-rise buildings face unnecessary interruptions due to excessive rope sway, which can be dangerous and disrupt service, as they only interrupt operations based on post-occurrence estimation rather than predictive measures.
Innovation Solution
A method and elevator system that predicts excessive rope sway by monitoring building acceleration and using a virtual model to estimate rope sway based on predicted elevator car positions, allowing for proactive countermeasures such as altering motion profiles, speed adjustments, or activating actuators to mitigate sway before it becomes critical.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elevator operation is interrupted based on current car position and building acceleration, then rope sway safety is improved, but elevator service continuity deteriorates due to unnecessary interruptions
Solution Approach 1:
The system performs preliminary action by predicting future car position and estimating future rope sway before the actual situation occurs. The controller predicts where the car will be, estimates the rope sway at that future position, and takes preventive action (interrupting operation) before the dangerous situation actually develops, rather than reacting after the fact.
Solution Approach 2:
The system uses feedback by continuously monitoring building acceleration data from sensors, comparing it against predicted car positions, and using this information to dynamically adjust elevator operation. The feedback loop includes sensing building motion, predicting its effect on rope sway, and responding appropriately to maintain safety while minimizing unnecessary interruptions.
2Reliability
If elevator operation is interrupted based on estimated rope sway, then safety is improved, but ride comfort deteriorates due to sudden stops
Solution Approach 1:
By predicting future rope sway conditions before they occur, the system can prepare for safety interventions in advance. This allows for smoother, more gradual speed reductions rather than sudden stops, as the controller can begin deceleration earlier in the travel cycle when the predicted dangerous condition is anticipated but not yet reached.
Solution Approach 2:
The system dynamically adjusts the elevator speed profile based on predicted rope sway conditions. Rather than using fixed interrupt thresholds, the controller continuously adapts the speed reduction strategy to match the predicted timing and severity of rope sway events, optimizing both safety and ride comfort by smoothing the transition.
3Device complexity
If reactive interruption based on current position is used, then system complexity is minimized, but response time to excessive rope sway deteriorates
Solution Approach 1:
The system calculates predicted car position and estimates future rope sway conditions in advance of when they will actually occur. This time advance allows the control system to initiate speed reductions or other corrective actions before the dangerous situation develops, effectively reducing the response time to excessive rope sway without requiring complex real-time intervention systems.
Data Source
AI summary
The invention relates to a method for operating an elevator installed in connection with a building, particularly a high rise elevator, in which method the expected rope sway is monitored using building acceleration data obtained by means of a sensor to calculate a building sway, and whereby based on the building sway and the position of an elevator car a rope sway is estimated, which rope sway is compared with a threshold value to determine excessive rope sway and to deduct operation measures for the elevator in order to counteract a determined excessive rope sway. According to the invention a succession of following steps is performed:determining a movement profile for the elevator car by means of an elevator controllerpredicting the elevator car position based on the movement profilecalculating the estimated rope sway based on the predicted car position and the building acceleration data.This leads to an early detection of a possible excessive rope sway happening in the future in course of servicing elevator calls by the allocated elevator car.