Elevator Rope Sway Mitigation via Building Sway Mode Control

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Solution Overview

Problem

Elevator systems in tall buildings experience significant rope sway during high winds, leading to excessive vertical vibration and noise, which existing mechanical solutions fail to adequately mitigate, often resulting in unserviceable floors and reduced elevator performance.

Innovation Solution

Implementing a building sway mode in the elevator control system that detects sway and adjusts operations by stopping or rerouting elevator cars, limiting time in critical zones, and using varying tie-down sheaves to manage rope sway, thereby reducing vibratory effects on the elevator car.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If mechanical elements such as sway arms, snubbing devices, car followers, rope guides, isolators are deployed to mitigate rope sway, then rope sway amplitude is reduced, but system cost increases and reliability is insufficient

Engineering Contradiction:

Improverope sway amplitudeVSAvoidreliability of sway mitigation

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent replaces mechanical sway mitigation elements with a control system that uses sensors to detect building sway and dynamically adjusts elevator car operation. The control system modifies acceleration, deceleration, and stopping patterns to counteract rope sway effects, eliminating the need for mechanical devices while improving reliability through active control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The control system changes operational parameters such as acceleration rates, deceleration rates, and stopping positions based on detected building sway conditions. By dynamically adjusting these parameters, the system mitigates rope sway effects without requiring additional mechanical components, thereby reducing cost while maintaining or improving reliability.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If tie down sheave adjustment is used to minimize compensation rope sway during high wind events, then rope sway is reduced, but many floors become unserviceable during building sway events

Engineering Contradiction:

Improvecompensation rope swayVSAvoidelevator serviceability

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The system dynamically adjusts elevator car operation in real-time based on detected building sway conditions. Rather than statically limiting service to certain floors, the control system continuously modifies acceleration, deceleration, and stopping patterns to mitigate rope sway effects, allowing all floors to remain serviceable while reducing harmful vibrations through active operational adjustments.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control system uses sensors to detect building sway conditions and feeds this information back to dynamically adjust elevator operation. This closed-loop control enables the system to respond to actual sway conditions, maintaining floor serviceability while actively mitigating rope sway effects through real-time operational modifications.

Inventive Principle:

Principle #23Feedback

3Productivity

If elevator cars operate continuously during building sway events, then productivity is maintained, but excessive vertical vibration and noise occur at the elevator car

Engineering Contradiction:

Improveelevator service continuityVSAvoidvertical vibration and noise

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The control system introduces periodic stopping patterns during elevator travel to mitigate rope sway effects. By strategically pausing car operation at specific intervals and positions, the system reduces cumulative rope sway and resulting vibrations while maintaining overall productivity through continued service to all floors.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The control system modifies travel patterns to rush through critical zones where rope sway effects are most severe by minimizing time spent at speeds that exacerbate vibrations, while maintaining service continuity through alternative routing or timing strategies that avoid excessive vibration and noise.

Inventive Principle:

Principle #21Skipping (Rushing through)

Data Source

PatentUS9914619B2Elevator rope sway mitigation

Publication Date: 2018.03.13 OTIS ELEVATOR CO

AI summary

A method of operating an elevator system includes detecting a building sway which causes sway of elevator suspension or compensation members. An elevator control system is switched into a building sway mode, and operation of one or more elevator cars of the elevator system is changed via the building sway mode to mitigate vibratory effects of the building sway on the one or more elevator cars.