Optimal design of control device to reduce elevator ropes responses against earthquake excitation using Genetic Algorithms

Abstract

In this paper, the reduction of the displacement responses of the elevator ropes under earthquake excitation has been investigated. The simultaneous vibrations of main rope and compensation rope in a high-rise building under earthquake excitation have been simulated. The varying length of rope is considered that caused the variation of other rope parameters such as mass, damping and stiffness. In order to reduce displacement responses of the compensation rope and the main rope, an actuator device which will change the tension of the ropes is applied at the compensation sheave. The vibrations of both ropes are analyzed by solving numerically the governing equations. A controller is proposed to restrain the displacement responses of the both ropes. A Genetic Algorithm which minimizes the displacement of the ropes and optimizes the control parameters, is introduced and applied to the high-rise elevator rope under earthquake excitations. The expected parameters are provided by standard deviation method. By using the expected control parameters, the proposed method is applied to control the vibrations of both ropes under some cases of earthquakes which are different with the earthquakes in Genetic Algorithm process. The results of the simulation validate the effectiveness of the proposed control method for reducing the displacement responses of the ropes.