Elevator Rope Vibration Control With Stable Negative Restoring Force

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing vibration suppression devices for elevator ropes exhibit unstable negative restoring forces that increase nonlinearly with rope displacement, leading to unstable rope displacement and ineffective vibration suppression.

Innovation Solution

A vibration suppression device for elevator ropes that includes a displacement measurement unit, a displacement amplifier, and a control unit to apply a negative restoring force that amplifies rope displacement while remaining smaller than the positive restoring force, using a control unit to manage the negative restoring force within safe limits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If an unstable mechanism with inverted lever and spring is used to produce negative restoring force, then the negative restoring force increases with displacement amplification, but the rope displacement becomes unstable when displacement increases excessively

Engineering Contradiction:

Improvenegative restoring forceVSAvoidrope displacement stability

Core Design Contradiction:

PowerVSStability of the object's composition

Solution Approach 1:

The patent replaces the unstable mechanical mechanism (inverted lever and spring) with an active control system using actuators and controllers. The control unit calculates the required negative restoring force based on measured displacement and applies it through actuators, eliminating the inherent instability of mechanical leverage systems while maintaining the amplitude amplification function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a feedback control system where displacement sensors continuously measure rope displacement, the control unit processes this information to calculate the appropriate negative restoring force, and actuators apply the calculated force. This closed-loop feedback mechanism ensures the negative restoring force remains proportional to displacement without the nonlinear instability characteristics of mechanical leverage systems.

Inventive Principle:

Principle #23Feedback

2Productivity

If negative restoring force is used to amplify displacement, then vibration suppression is achieved through frictional resistance, but the system cannot suppress vibration when displacement becomes unstable

Engineering Contradiction:

Improvevibration suppression effectivenessVSAvoidvibration suppression reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent replaces the passive mechanical vibration suppression mechanism (relying on frictional resistance from unstable leverage) with an active control system. The control system actively generates the negative restoring force through actuators, ensuring reliable vibration suppression across the full range of displacements without dependence on unstable mechanical friction.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent dynamically adjusts the negative restoring force parameter based on real-time displacement measurements. The control unit calculates the optimal negative restoring force magnitude to maintain stable displacement amplification while effectively suppressing vibrations, adapting the force parameter to varying operating conditions rather than relying on fixed mechanical properties.

Inventive Principle:

Principle #35Parameter changes

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

The device effectively suppresses rope vibrations by amplifying displacement with a controlled negative restoring force, preventing unstable displacement and maintaining stable operation of the elevator system.

Implementation Method 1

a first displacement amplifier to apply, to the rope-like body, a negative restoring force that amplifies the displacement of the rope-like body

Methodology Applied

Scientific EffectNegative restoring force:

Implementation Method 2

a first displacement measurement unit to measure a displacement in a lateral direction of the rope-like body due to vibration about an equilibrium position

Methodology Applied

Scientific EffectDisplacement measurement:

Implementation Method 3

a control unit to cause the first displacement amplifier to apply the negative restoring force smaller than a positive restoring force to return the rope-like body to the equilibrium position

Methodology Applied

Scientific EffectPositive restoring force:

Data Source

PatentUS12359705B2Vibration suppression device for rope-like body of elevator

Publication Date: 2025.07.15 MITSUBISHI ELECTRIC CORP

AI summary

There is provided a vibration suppression device of a rope-like body that can use a negative restoring force that amplifies a displacement of a rope-like body of an elevator to prevent the displacement from becoming unstable. A vibration suppression device (21) includes a first displacement measurement unit, a first displacement amplifier, and a control unit (24). The first displacement measurement unit measures a displacement in a lateral direction of the rope-like body due to vibration about an equilibrium position (20) at a first position (P1) in a longitudinal direction of the rope-like body. The first displacement amplifier applies, to the rope-like body, a negative restoring force that amplifies the displacement of the rope-like body. The control unit (24) causes the first displacement amplifier to apply a negative restoring force smaller than a positive restoring force, based on the displacement measured by the first displacement measurement unit.