# US 9,434,577 B2 · Semi-active feedback control of elevator rope sway

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- Number: US 9,434,577 B2
- Document ID: US9434577B2
- Status: Granted
- Kind: B2
- Application number: 13/948,872
- Filed: 2013-07-23
- Published: 2015-01-29
- Granted: 2016-09-06
- Earliest claimed: 2013-07-23
- Assignees: Mitsubishi Electric Research Laboratories, Inc.
- Applicants: Mitsubishi Electric Research Laboratories, Inc.
- Inventors: Mouhacine Benosman
- Web page: https://patentgrep.com/patent/US9434577B2

## CPC

- B66B 5/02: responsive to abnormal operating conditions
- B66B 7/06: Arrangements of ropes or cables
- B66B: ELEVATORS; ESCALATORS OR MOVING WALKWAYS ({apparatus for raising or lowering persons on theatrical stages or the like A63J5/12} ; funicular railbound systems with rigid ground-supported tracks and cable traction, e.g. cliff railways, B61B9/00; arrangements of ammunition handlers in vessels B63G3/00; hoists, lifts, or conveyors for loading or unloading in general B65G; braking or detent devices controlling normal movements of winding drums or barrels B66D; ship-lifting devices E02C; garages for many vehicles with mechanical means for lifting vehicles E04H6/12; hoists for feeding ammunition or projectiles to launching apparatus or to loading mechanisms F41A9/00)

## Abstract

A method controls an operation of an elevator system. The method receives an amplitude of a sway of an elevator rope and a velocity of the sway of the elevator rope determined during the operation of the elevator system. The method modifies a damping coefficient of a semi-active damper actuator connected to the elevator rope according to a function of the amplitude and the velocity of the sway.

## Claims

### Claim 1

A method for controlling an operation of an elevator system, comprising:
receiving an amplitude of a sway of an elevator rope and a velocity of the sway of the elevator rope determined during the operation of the elevator system;
modifying, in response to the receiving, a damping coefficient of a semi-active damper actuator connected to the elevator rope according to a function of the amplitude and the velocity of the sway, wherein steps of the method are performed by a processor; and
determining a control law stabilizing a state of the elevator system, wherein the control law determines a value of the damping coefficient based on the function, such that the value of the damping coefficient ensures a negative definiteness of a derivative of a control Lyapunov function, wherein the control law assigns the value of the damping coefficient of the semi-active damper actuator based on a sign of a product of the amplitude of the sway of the elevator rope and the velocity of the sway of the elevator rope.

### Claim 2 (depends on 1)

The method of claim 1, wherein the modifying is according to a sign of the function.

### Claim 3 (depends on 1)

The method of claim 1, wherein the control law is determined such that the value of the damping coefficient of the semi-active damper actuator is proportional to the amplitude of the sway of the elevator rope.

### Claim 4 (depends on 1)

The method of claim 1, wherein the control law determines a switching condition for the value of the damping coefficient based on a sign of the function.

### Claim 5 (depends on 1)

The method of claim 1, wherein the control law assigns the value of the damping coefficient of the semi-active damper actuator based on a sign of a product of the amplitude of the sway of the elevator rope and the velocity of the sway of the elevator rope.

### Claim 6 (depends on 1)

The method of claim 1, further comprising:
determining the control law for the elevator system based on a model of the elevator system without an external disturbance; and
modifying the control law with a disturbance rejection component to force the derivative of the Lyapunov function to be negative definite with the external disturbance.

### Claim 7 (depends on 1)

The method of claim 1, wherein the control law U(x) includes
U
⁡
(
x
)
=
{
u_max
if
⁢
⁢
(
C
~
⁢
q
.
+
β
⁢
⁢
q
)
⁢
q
.
>
0
u_min
if
⁡
(
C
~
⁢
q
.
+
β
⁢
⁢
q
)
⁢
q
.
≤
0
,
wherein u_min is a positive constant representing the minimum damping coefficient of the semi-active damper and u_max is a positive constant representing a maximal damping coefficient of the semi-active damper actuator, x=(q,{dot over (q)}), and q, {dot over (q)} are Lagrangian variables representing an assumed mode and a time derivative of the assumed mode, and {tilde over (C)},β are coefficients of a model of the elevator system.

### Claim 8 (depends on 1)

The method of claim 1, wherein the control law U(x) includes
U
⁡
(
x
)
=
{
k
⁡
(
C
~
⁢
q
.
+
β
⁢
⁢
q
)
⁢
q
.
1
+
(
(
C
~
⁢
q
.
+
β
⁢
⁢
q
)
⁢
q
.
)
2
if
⁡
(
C
~
⁢
q
.
+
β
⁢
⁢
q
)
⁢
q
.
>
0
u_min
if
⁡
(
C
~
⁢
q
.
+
β
⁢
⁢
q
)
⁢
q
.
≤
0
,
wherein x=(q, {dot over (q)}), and q, {dot over (q)} are Lagrangian variables representing an assumed mode and a time derivative of the assumed mode, k is a positive feedback gain less than u_max, u_min is a positive constant representing the minimum damping coefficient of the semi-active damper, u_max is a positive constant representing a maximal damping coefficient of the semi-active and {tilde over (C)},β are coefficients of a model of the elevator system.

### Claim 9 (depends on 1)

The method of claim 1, wherein the control law u(x) includes
U(x)=U_{nom}(x)+v(x)
wherein
v(x)=({tilde over (k)}|U_{nom}|+{tilde over (h)})sign({tilde over (C)}{dot over (q)}2+βq{dot over (q)}−{tilde over (F)}(t){dot over (q)})(F_{max}+ε)|{dot over (q)}|{tilde over (k)}>0,{tilde over (h)}>0,ε>0,F_{max}≧max(F(t),{tilde over (F)}(t)),∀t
wherein x=(q, {dot over (q)}), and q, {dot over (q)} are Lagrangian variables representing an assumed mode and a time derivative of the assumed mode, and {tilde over (k)}, {tilde over (h)}, ε are positive gains, {tilde over (C)},β are coefficients obtained from a model of the elevator system, F_{max} represents an upper bound of a disturbances F(t) and F, {tilde over (F)}, U_{nom} represents a control law without the disturbance and a sign function is
sgn
⁡
(
v
)
:=
{
1
if
⁢
⁢
v
>
0
-
1
if
⁢
⁢
v
<
0
.

### Claim 10 (depends on 1)

The method of claim 1, wherein the semi-active damper actuator is placed between a top of an elevator car and a main rope, or between a top of a counterweight and the main rope.

### Claim 11 (depends on 1)

The method of claim 1, wherein the semi-active damper is placed between a bottom of an elevator car and a compensation rope or between a bottom of a counterweight and the compensation rope.

### Claim 12

An elevator system, comprising:
an elevator car and a counterweight of the elevator car;
an elevator rope connected to the elevator car or to the counterweight;
a semi-active damper actuator connected to the elevator rope;
a sway unit for determining an amplitude of a sway of an elevator rope and a velocity of the sway of the elevator rope; and
a control unit for determining a damping coefficient of the semi-active damper actuator according to a function of the amplitude and the velocity of the sway of the elevator rope, wherein the control unit determines the damping coefficient according a control law stabilizing a state of the elevator system, wherein the control law determines a value of the damping coefficient based on the function, such that the value of the damping coefficient ensures a negative definiteness of a derivative of a control Lyapunov function, wherein the control law includes a disturbance rejection component to force the derivative of the Lyapunov function to be negative definite with an external disturbance.

### Claim 13 (depends on 12)

The elevator system of claim 12, wherein the control unit determines the damping coefficient according to a sign of the function.

### Claim 14 (depends on 12)

The elevator system of claim 12, wherein the control law is determined such that the value of the damping coefficient of the semi-active damper actuator is proportional to the amplitude of the sway of the elevator rope.

### Claim 15 (depends on 12)

The elevator system of claim 12, wherein the control law determines a switching condition for the value of the damping coefficient based on a sign of the function.

### Claim 16 (depends on 12)

The elevator system of claim 12, wherein the control law assigns the value of the damping coefficient of the semi-active damper actuator based on a sign of a product of the amplitude of the sway of the elevator rope and the velocity of the sway of the elevator rope.

### Claim 17

A method for controlling an operation of an elevator system, comprising:
receiving an amplitude of a sway of an elevator rope and a velocity of the sway of the elevator rope determined during the operation of the elevator system;
modifying, in response to the receiving, a damping coefficient of a semi-active damper actuator connected to the elevator rope according to a function of the amplitude and the velocity of the sway;
determining a control law stabilizing a state of the elevator system, wherein the control law determines a value of the damping coefficient based on the function, such that the value of the damping coefficient ensures a negative definiteness of a derivative of a control Lyapunov function;
determining the control law for the elevator system based on a model of the elevator system without an external disturbance; and
modifying the control law with a disturbance rejection component to force the derivative of the Lyapunov function to be negative definite with the external disturbance, wherein steps of the method are performed by a processor.