Controlling sway of elevator cable connected to elevator car

Patent metadata

Field	Value
Publication number	US-9862570-B2
Application number	US-201615066102-A
Country	US
Kind code	B2
Filing date	Mar 10, 2016
Priority date	Mar 10, 2016
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

A method for controlling an operation of an elevator system is discloses. The elevator system includes an elevator car moving within an elevator shaft and at least one elevator cable connected to the elevator car and the elevator shaft to carry electrical signals to the elevator car. The method determines a counter force on the elevator cable required to change a nominal shape of the elevator cable to an inverse shape of a current shape of the elevator cable caused by disturbance on the elevator system and applies the counter force to the elevator cable.

First claim

We claim:

1. A method for controlling an operation of an elevator system including an elevator car moving within an elevator shaft and an elevator cable connected to the elevator car and the elevator shaft to carry electrical signals to the elevator car, comprising:
measuring an amplitude and a velocity of a sway of the elevator cable caused by disturbance on the elevator system;
determining a counter force on the elevator cable required to change a nominal shape of the elevator cable to an inverse shape of a current shape of the elevator cable caused by the disturbance on the elevator system, wherein the counter force is determined according to a control law as a function of the amplitude and the velocity of the sway, wherein the control law is determined to stabilize an energy function of dynamics of the elevator cable to produce a value of an acceleration Uc of the elevator car resulting in application of the counter force to the elevator cable, wherein the control law includes

Uc
=

k
c

⁢

θ
c

⁢

θ
.

c

⁢



θ
.

ω



1
+

θ
c
2

⁢

θ
.

c
2

⁢

θ
.

ω
2

,

⁢

k
c

>
0

wherein k c , is a positive tuning gain, θ c is an angular sway amplitude of the elevator cable in proximity to the elevator car, θ w is an angular sway amplitude of the elevator cable in proximity to a wall of the elevator shaft, {dot over (θ)} c is an angular sway velocity of the elevator cable in proximity to the elevator car, and {dot over (θ)} w is an angular sway velocity in proximity to the wall of the elevator shaft; and
applying the counter force to the elevator cable by moving the elevator car with the acceleration having the value produced by the control law, wherein at least some steps of the method are performed using a processor.

2. The method of claim 1 , wherein the energy function is a Lyapunov function along dynamics of the elevator cable, and wherein the control law is determined such that a derivative of the Lyapunov function is negative definite.

3. The method of claim 1 , wherein the control law produces oscillating values of the acceleration in response to a change of a sign of a product of the amplitude and the velocity of the sway of the elevator cable.

4. The method of claim 1 , wherein the control law includes a positive gain bounding an absolute value of the acceleration.

5. An elevator system comprising:
an elevator car supported by an elevator rope wrapped around a sheave, such that a rotation of the sheave changes a length of the elevator rope between the sheave and the elevator car thereby controlling a movement of the elevator car within an elevator shaft of the elevator system;
a motor to control a rotation of the sheave changing the length of the elevator rope;
an elevator cable connected to the elevator car and the elevator shaft;
a sway sensor to determine an amplitude and a velocity of a sway of the elevator cable;
a controller including a processor to determine a counter force on the elevator cable required to change a nominal shape of the elevator cable to a shape that is inverse of a current shape of the elevator cable caused by disturbance on the elevator system, and to cause the motor to rotate the sheave and to move the elevator car with an acceleration that applies the counter force to the elevator cable, wherein the processor determines the acceleration according to a control law as a function of the amplitude and the velocity of the sway, wherein the control law is determined to stabilize an energy function of dynamics of the elevator cable, wherein the control law includes

Uc
=

k
c

⁢

θ
c

⁢

θ
.

c

⁢



θ
.

ω



1
+

θ
c
2

⁢

θ
.

c
2

⁢

θ
.

ω
2

,

⁢

k
c

>
0

wherein k c , is a posi

Assignees

• Mitsubishi Electric Res Laboratories Inc
• Mitsubishi Electric Corp
• Misubishi Electric Corp

Inventors

• Benosman Mouhacine
• Nakazawa Daisuke
• Watanabe Seiji
• Fukui Daiki

Classifications

• B66B9/00

  Kinds or types of lifts in, or associated with, buildings or other structures (characterised by control systems B66B1/00; apparatus for raising or lowering persons on stages of theatres A63J5/12) · CPC title

• B66B7/06

  Arrangements of ropes or cables · CPC title

• B66B5/28

  Buffer-stops for cars, cages, or skips · CPC title

• B66B1/06 Primary

  electric · CPC title

• B66B1/3492

  Position or motion detectors or driving means for the detector (B66B1/40, B66B1/50 take precedence; length measuring G01B; speed measuring G01P) · CPC title