U.S. patent application number 10/746287 was filed with the patent office on 2004-10-07 for method for detecting dewatering load in washing machine and washing machine control method using the same.
Invention is credited to Kim, Jong Ho, Lyu, Jae Chul.
Application Number | 20040194226 10/746287 |
Document ID | / |
Family ID | 33095524 |
Filed Date | 2004-10-07 |
United States Patent
Application |
20040194226 |
Kind Code |
A1 |
Kim, Jong Ho ; et
al. |
October 7, 2004 |
Method for detecting dewatering load in washing machine and washing
machine control method using the same
Abstract
A method for detecting a dewatering load in a washing machine
and a washing machine control method using the same are provided.
The dewatering load is detected, and the washing machine is
controlled accordingly, by first determining an acceleration or
deceleration time and applying the principle that the laundry load
during dewatering corresponds to the time required for
accelerating/decelerating a washing tub driven by a motor, to drive
the washing tub at a predetermined rotational speed based on the
detection or to stop its rotation based on a determination of an
overload condition. The control method includes steps of initiating
a dewatering step, by driving the washing tub from a first
predetermined rotational speed to a second predetermined rotational
speed; detecting a load amount present in the driven washing tub,
using the principle that the load amount corresponds to a time
required for the driving of the washing tub from the first
predetermined rotational speed to the second predetermined
rotational speed; determining a time lapse between the driving of
the washing tub at the first predetermined rotational speed and the
driving of the washing tub at the second predetermined rotational
speed; comparing the determined time lapse with a reference value
in a lookup table; and performing dewatering based on the detected
load amount, wherein the dewatering is performed at a predetermined
maximum dewatering speed corresponding to the detected load amount
and wherein the dewatering is interrupted if the detected load
amount exceeds a predetermined reference value. The second
predetermined rotational speed may be a steady rotational speed,
whereby the driving of the washing tub is performed by accelerating
the washing tub by applying a constant motor torque. Alternatively,
the first predetermined rotational speed may be the steady
rotational speed, whereby the driving of the washing tub is
performed by decelerating the washing tub by way of freewheeling
the motor, applying dynamic braking, or applying anti-phase
braking.
Inventors: |
Kim, Jong Ho; (Changwon-si,
KR) ; Lyu, Jae Chul; (Changwon-si, KR) |
Correspondence
Address: |
FLESHNER & KIM, LLP
P.O. BOX 221200
CHANTILLY
VA
20153
US
|
Family ID: |
33095524 |
Appl. No.: |
10/746287 |
Filed: |
December 29, 2003 |
Current U.S.
Class: |
8/159 |
Current CPC
Class: |
D06F 35/006
20130101 |
Class at
Publication: |
008/159 |
International
Class: |
D06B 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 28, 2002 |
KR |
P2002-85806 |
Claims
What is claimed is:
1. A method for detecting a dewatering load in a washing machine
having a washing tub driven by a motor, the method comprising steps
of: driving the washing tub from a first predetermined rotational
speed to a second predetermined rotational speed; determining a
time lapse between the driving of the washing tub at the first
predetermined rotational speed and the driving of the washing tub
at the second predetermined rotational speed; and comparing the
determined time lapse with a set of reference values in a lookup
table.
2. The method as claimed in claim 1, wherein the second
predetermined rotational speed is a steady rotational speed and the
driving of the washing tub is performed by accelerating the washing
tub by applying a constant motor torque.
3. The method as claimed in claim 1, wherein the first
predetermined rotational speed is a steady rotational speed and the
driving of the washing tub is performed by decelerating the washing
tub by means of one of freewheeling the motor, applying dynamic
braking, and applying anti-phase braking.
4. A method for controlling a washing machine having a washing tub
driven by a motor, the method comprising steps of: initiating a
dewatering step, by driving the washing tub from a first
predetermined rotational speed to a second predetermined rotational
speed; detecting a load amount present in the driven washing tub,
using the principle that the load amount corresponds to a time
required for the driving of the washing tub from the first
predetermined rotational speed to the second predetermined
rotational speed; and performing dewatering based on the detected
load amount.
5. The method as claimed in claim 4, wherein the second
predetermined rotational speed is a steady rotational speed and the
driving of the washing tub is performed by accelerating the washing
tub by applying a constant motor torque.
6. The method as claimed in claim 5, the method further comprising
steps of: determining a time lapse between the driving of the
washing tub at the first predetermined rotational speed and the
driving of the washing tub at the second predetermined rotational
speed; and comparing the determined time lapse with a set of
reference values in a lookup table, wherein the dewatering is
performed at a predetermined maximum dewatering speed corresponding
to the detected load amount and wherein the dewatering is
interrupted if the detected load amount exceeds a predetermined
reference value.
7. The method as claimed in claim 4, wherein the first
predetermined rotational speed is a steady rotational speed and the
driving of the washing tub is performed by decelerating the washing
tub by means of one of freewheeling the motor, applying dynamic
braking, and applying anti-phase braking.
8. The method as claimed in claim 7, the method further comprising
steps of: determining a time lapse between the driving of the
washing tub at the first predetermined rotational speed and the
driving of the washing tub at the second predetermined rotational
speed; and comparing the determined time lapse with a reference
value in a lookup table, wherein the dewatering is performed at a
predetermined maximum dewatering speed corresponding to the
detected load amount and wherein the dewatering is interrupted if
the detected load amount exceeds a predetermined reference value.
Description
[0001] This application claims the benefit of Korean Application
No. 10-2002-0085806 filed on Dec. 28, 2002, which is hereby
incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a washing machine, and more
particularly, to a method for detecting a dewatering load in a
washing machine and a washing machine control method using the
same, in which the dewatering load is detected and the washing
machine is controlled accordingly, by first determining an
acceleration or deceleration time and applying the principle that
the laundry load during dewatering corresponds to the time required
for accelerating/decelerating a washing tub.
[0004] 2. Discussion of the Related Art
[0005] Generally speaking, a washing machine is an apparatus for
cleaning an object such as laundry and typically employs a washing
tub in which the laundry and a predetermined amount of water is
rotated under the control of a microcomputer using an algorithm set
according to a selected wash course to perform in sequence washing,
rinsing, draining, and dewatering steps. The washing tub is driven
at a predetermined speed for each step. A contemporary washing
machine may use any one of several drive and control techniques for
rotating the washing tub to perform the above steps, including
transferring a rotational force via a belt-and-pulley linkage to a
dewatering shaft to rotate the tub, transferring a rotational force
via a belt-and-pulley linkage to a washing shaft to rotate a
pulsator or drum, controlling the speed of a BLDC motor, to rotate
the tub at two different speeds (for washing and dewatering),
separately controlling a power transfer path of a BLDC motor, to
rotate a pulsator at a first speed (for washing) and rotating the
pulsator and tub at a second speed (for dewatering), and performing
"penetration" washing, by pumping a current of water into the tub
while rotating the tub or wash vanes.
[0006] In particular, dewatering is performed at a much higher
speed than washing, such that the washing machine may exhibit
"striking," which is a phenomenon whereby rotation is performed in
an overloaded condition, such that the washing tub strikes adjacent
surfaces of the washing machine during high-speed rotation,
generating undue vibration, excessive noise, and even system
damage. To guard against striking, dewatering speed should be
carefully controlled, and in the event of an overload condition,
dewatering should be stopped (aborted), since dewatering without
accurate dewatering load detection may result in improper
dewatering, i.e., improper speed or duration, or may cause damage
to the system due to immoderate operation. Therefore, to enhance
system stability and reliability, a method is needed for the
accurate detection of the dewatering load before the execution of
high-speed rotation of the washing tub to perform dewatering.
SUMMARY OF THE INVENTION
[0007] Accordingly, the present invention is directed to a method
for detecting a dewatering load in a washing machine, and a washing
machine control method using the same, that substantially obviates
one or more of the problems due to limitations and disadvantages of
the related art.
[0008] An object of the present invention, which has been devised
to solve the foregoing problem, lies in providing a method for
detecting a dewatering load in a washing machine, and a washing
machine control method using the same, which accurately detects
dewatering load and controls the washing machine accordingly, by
first determining an acceleration or deceleration time and applying
the principle that the laundry load during dewatering corresponds
to the time required for accelerating/decelerating a washing tub
driven by a motor, to drive the washing tub at a predetermined
rotational speed based on the detection or to stop its rotation
based on a determination of an overload condition.
[0009] It is another object of the present invention to provide a
method for detecting a dewatering load in a washing machine, and a
washing machine control method using the same, which accurately
detects a dewatering load before the execution of high-speed
rotation of the washing tub to perform dewatering.
[0010] It is another object of the present invention to provide a
method for detecting a dewatering load in a washing machine, and a
washing machine control method using the same, which prevents the
occurrence of striking during dewatering.
[0011] It is another object of the present invention to provide a
method for detecting a dewatering load in a washing machine, and a
washing machine control method using the same, which controls the
dewatering speed based on a dewatering load detected before the
execution of high-speed rotation of the washing tub to perform
dewatering, by comparing the detected dewatering load with a
predetermined value.
[0012] It is another object of the present invention to provide a
method for detecting a dewatering load in a washing machine, and a
washing machine control method using the same, which interrupts or
aborts the execution of dewatering in the event of an overload
condition.
[0013] It is another object of the present invention to provide a
method for detecting a dewatering load in a washing machine, and a
washing machine control method using the same, which enhances
system stability and reliability.
[0014] Additional features and advantages of the invention will be
set forth in the description which follows, and in part will be
apparent to those having ordinary skill in the art upon examination
of the following or may be learned from a practice of the
invention. The objectives and other advantages of the invention
will be realized and attained by the subject matter particularly
pointed out in the specification and claims hereof as well as in
the appended drawings.
[0015] To achieve these objects and other advantages in accordance
with the present invention, as embodied and broadly described
herein, there is provided a method for detecting a dewatering load
in a washing machine having a washing tub driven by a motor. The
detection method comprises steps of driving the washing tub from a
first predetermined rotational speed to a second predetermined
rotational speed; determining a time lapse between the driving of
the washing tub at the first predetermined rotational speed and the
driving of the washing tub at the second predetermined rotational
speed; and comparing the determined time lapse with a set of
reference values in a lookup table.
[0016] In one embodiment of the present invention, the second
predetermined rotational speed is a steady rotational speed and the
driving of the washing tub is performed by accelerating the washing
tub by applying a constant motor torque. In another embodiment, the
first predetermined rotational speed is a steady rotational speed
and the driving of the washing tub is performed by decelerating the
washing tub by means of one of freewheeling the motor, applying
dynamic braking, and applying anti-phase braking.
[0017] In another aspect of the present invention, there is
provided a method for controlling a washing machine having a
washing tub driven by a motor. The control method comprises steps
of initiating a dewatering step, by driving the washing tub from
the first predetermined rotational speed to the second
predetermined rotational speed; detecting a load amount present in
the driven washing tub, using the principle that the load amount
corresponds to a time required for the driving of the washing tub
from the first predetermined rotational speed to the second
predetermined rotational speed; and performing dewatering based on
the detected load amount.
[0018] Preferably, the control method further comprises steps of
determining a time lapse between the driving of the washing tub at
the first predetermined rotational speed and the driving of the
washing tub at the second predetermined rotational speed; and
comparing the determined time lapse with a reference value in a
lookup table, wherein the dewatering is performed at a
predetermined maximum dewatering speed corresponding to the
detected load amount and wherein the dewatering is interrupted if
the detected load amount exceeds a predetermined reference
value.
[0019] It is to be understood that both the foregoing explanation
and the following detailed description of the present invention are
exemplary and illustrative and are intended to provide further
explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this application, illustrate embodiment(s) of
the invention and together with the description serve to explain
the principle of the invention. In the drawings:
[0021] FIG. 1A is a graph plotting the rotational speed of a
washing tub, during the execution of dewatering in a washing
machine adopting the method of the present invention, according to
a first embodiment;
[0022] FIG. 1B is a graph plotting the rotational speed of a
washing tub, during the execution of dewatering in a washing
machine adopting the method of the present invention, according to
a second embodiment; and
[0023] FIG. 2 is a graph illustrating the relationship between
washing tub speed and laundry load during dewatering, for
explaining the principle of the method of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] Reference will now be made in detail to the preferred
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings.
[0025] Referring to FIGS. 1A and 1B, respectively illustrating a
dewatering load detection and control method according to first and
second embodiments of the present invention, a load amount is
detected in a washing machine having a washing tub driven by a
motor to perform dewatering by a high-speed rotation of the washing
tub. At the time of initiating a dewatering step, and before the
high-speed rotation of the washing tub, the washing tub is
controlled to be driven from a first predetermined rotational speed
to a second predetermined rotational speed, and the elapsed time
required for the above driving of the washing tub is determined.
Thereafter, the load amount is obtained by comparing the determined
time lapse with a set of reference values in a lookup table
recording a predetermined set of known laundry load amounts. That
is, a predetermined maximum dewatering speed is set for each
laundry load amount. The lookup table may be stored in a memory of
the microcomputer of the washing machine.
[0026] In the first embodiment of the present invention, the second
predetermined rotational speed is a steady rotational speed and the
driving of the washing tub is performed by accelerating the washing
tub by applying a constant motor torque. In the second embodiment,
the first predetermined rotational speed is a steady rotational
speed and the driving of the washing tub is performed by
decelerating the washing tub by means of one of freewheeling the
motor, applying dynamic braking, and applying anti-phase braking.
The dewatering load detection method of the present invention uses
the principle that the laundry load during dewatering corresponds
to the time required for accelerating/decelerating the washing tub.
That is, the accelerating/decelerating time is proportional to an
inertial force acting on the load, and the inertial force is
proportional to the load amount.
[0027] In detecting a dewatering load to perform dewatering in a
washing machine adopting a first embodiment of the method of the
present invention, the washing tub is accelerated as shown in FIG.
1A to obtain an acceleration time .DELTA.t1 and thereby detect the
dewatering load before proceeding the dewatering. In detecting a
dewatering load to perform dewatering in a washing machine adopting
a second embodiment of the method of the present invention, the
washing tub is decelerated as shown in FIG. 1B to obtain a
deceleration time .DELTA.t2 and thereby detect the dewatering load
before proceeding the dewatering. According to the present
invention, the dewatering load may be accurately detected based on
either the acceleration or deceleration, but a more reliable
detection can be achieved by obtaining both the acceleration time
.DELTA.t1 and the deceleration time .DELTA.t2. In such a case,
acceleration preferably precedes deceleration since deceleration
requires a higher initial speed.
[0028] Referring to the method illustrated in FIG. 1A, using
washing tub acceleration, a washing tub is driven by a motor upon
the initiation of a dewatering step, whereupon the initial
rotational speed of the washing tub is substantially zero.
Thereafter, the washing tub is accelerated to a predetermined
steady rotational speed, by applying a constant motor torque, and
an elapsed time is measured to obtain an acceleration time
.DELTA.t1 required for the tub speed to reach a state of steady
rotation. The acceleration time .DELTA.t1 is measured from the
point of initiating the acceleration, which may be a stopped state
or a predetermined slow rate of rotation. The difference between
the initial speed and the predetermined steady rotational speed
after acceleration is an acceleration value .DELTA.rpm1. The
dewatering load is detected as a direct result of obtaining the
acceleration time .DELTA.t1. That is, the acceleration time
.DELTA.t1 corresponds to a known laundry load amount referenced in
the lookup table, to indicate a predetermined maximum dewatering
speed for the laundry load amount. Then, the drive of the washing
tub is controlled according to the predetermined maximum dewatering
speed most appropriate for the detected dewatering load. In the
event that the detected dewatering load exceeds a predetermined
reference value, an overload condition is determined so that the
dewatering step may be interrupted or aborted.
[0029] Referring to the method illustrated in FIG. 1B, using
washing tub deceleration, a washing tub is driven by a motor upon
the initiation of a dewatering step, such that a predetermined
steady rotational speed before deceleration is reached. Thereafter,
the washing tub is decelerated to a predetermined rotational speed,
and an elapsed time is measured to obtain a deceleration time
.DELTA.t2 required for the tub speed to reach the predetermined
decelerated rotational speed from the point of initiating the
deceleration. The difference between the predetermined steady
rotational speed before deceleration and the predetermined
decelerated rotational speed is a deceleration value .DELTA.rpm2.
The dewatering load is detected as a direct result of obtaining the
deceleration time .DELTA.t2. That is, the deceleration time
.DELTA.t2 corresponds to a known laundry load amount referenced in
the lookup table, to indicate a predetermined maximum dewatering
speed for the laundry load amount. Then, the drive of the washing
tub is controlled according to the predetermined maximum dewatering
speed most appropriate for the detected dewatering load. In the
event that the detected dewatering load exceeds a predetermined
reference value, an overload condition is determined so that the
dewatering step may be interrupted or aborted.
[0030] Here, deceleration can be achieved by any one of turning off
the motor (freewheeling), dynamic braking, or anti-phase braking.
In freewheeling the motor, the application of electrical power to
the motor may be removed or an applied drive signal may have a duty
ratio of zero; in dynamic braking, two of three motor phases are
shorted together; and in anti-phase braking, a reverse rotational
force is generated and applied by the motor.
[0031] The present invention detects an accurate load amount by a
measurement of the acceleration and/or deceleration times with
respect to a steady rotational speed of a washing tub undergoing a
dewatering step, since the acceleration and deceleration times are
each longer for larger laundry load amounts which produce larger
dewatering load amounts, as demonstrated by FIG. 2. The dewatering
load is then determined by referencing the measured time lapse with
respect to a lookup table, and the washing tub is driven
accordingly. That is, the dewatering is performed at a
predetermined maximum dewatering speed corresponding to the
detected load amount and is interrupted or aborted if the detected
load amount exceeds a predetermined reference value indicating an
overload condition. Thus, the present invention accurately detects
the load amount upon initiation of a dewatering step, so that a
determination can be made as to whether the dewatering should be
progressed.
[0032] By adopting the present invention to a conventional washing
machine, a dewatering load can be accurately detected before the
execution of high-speed rotation of the washing tub to perform
dewatering, so that the occurrence of striking during dewatering
can be prevented to enhance system stability and reliability.
[0033] It will be apparent to those skilled in the art that various
modifications and variations can be made in the present invention
without departing from the spirit or scope of the invention. Thus,
it is intended that the present invention cover such modifications
and variations, provided they come within the scope of the appended
claims and their equivalents.
* * * * *