Patent Publication Number: US-2013247307-A1

Title: Washing machine and control method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Korean Patent Application No. 2012-0028089, filed on Mar. 20, 2012 and No. 2012-0056832, filed on May 29, 2012 in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     Embodiments of the present disclosure relate to a washing machine for reducing vibration and noise during a spin-drying cycle, and a control method thereof. 
     2. Description of the Related Art 
     In general, a washing machine (for example, a fully automatic washing machine) includes a water tank for storing water (wash water or rinse water), a washing tub for accommodating laundry (hereinafter referred to as “cloth”), a pulsator rotatably installed in the washing tub to generate water current, and a motor for generating a driving force to rotate the washing tub and the pulsator. When the washing tub rotates, the cloth is washed by the interfacial operation between the water current and detergent. 
     Such a washing machine carries out washing in a series of operations of a washing cycle for separating contaminants from cloth with water (specifically, wash water) with detergent dissolved therein, a rinsing cycle for rinsing the cloth with water (specifically, rinse water) with no detergent to remove bubbles or residual detergent from the cloth, and a spin-drying cycle for removing moisture contained in the cloth by high-speed rotation of the washing tub. When the washing tub is rotated in an imbalanced state with the cloth not distributed uniformly in the washing tub while washing proceeds in such a series of operations, a biased force is applied to a rotation shaft of the washing tub so that the washing tub makes eccentric motion, thereby causing vibration of the water tank. Such vibration of the water tank becomes more severe when the washing tub rotates at high speed for the spin-drying cycle, thereby causing greater vibration and noises. 
     Recently as the size of the washing tub increases with the increase of the capacity of the washing machine, vibration of the water tank becomes so severe that the water tank collides with a frame of the washing machine, so the whole of the washing machine vibrates abnormally to impede the spin-drying cycle and cause unsatisfactory spin-drying. 
     In order to solve such a problem, a method in which a checker switch is installed between a frame and a water tank to stop spin-drying when the water tank comes into contact with the checker switch by excessive vibration of the water tank in the spin-drying cycle and spin-drying is reattempted after water is resupplied to loosen the cloth is conventionally used. However, such a method has drawbacks including decreased energy efficiency and increased water consumption and spin-drying time. 
     SUMMARY 
     Therefore, it is an aspect of the present disclosure to provide a washing machine in which the distribution of the cloth is made uniform so as to reduce vibration and noise during the spin-drying cycle, and a control method thereof. 
     Additional aspects and/or advantages will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the disclosure. 
     In accordance with one aspect of the present disclosure, a method of controlling a washing machine including a washing tub accommodating cloth and a pulsator rotatably installed in the washing tub, includes (a) rotating the pulsator in one direction for a first time before supplying water to the washing tub; (b) stopping the pulsator for a second time after the pulsator rotates in one direction; (c) rotating the pulsator in an opposite direction for a third time when the second time elapses; and (d) stopping the pulsator for a fourth time after the pulsator rotates in the opposite direction, wherein a balance cycle may be carried out by performing a stirring operation of the pulsator configured of operations (a) to (d) from side to side at least once or more so as to uniformly distribute the cloth. 
     The balance cycle may be carried out before a water supply cycle of first supplying water for washing the cloth. 
     The method may further include rotating the pulsator by a motor, wherein the pulsator may be driven in a forward direction for the first time while maintaining the motor at a predetermined RPM during the rotation of the pulsator in one direction. 
     The pulsator may be driven in a backward direction for the third time while maintaining the motor at a predetermined RPM during the rotation of the pulsator in an opposite direction. 
     The first time may be set to be equal to the third time, and the second time may be set to be equal to the fourth time. 
     The second time may be set to be shorter than the first time, the first time may be set to be 1.4 seconds, and the second time may be set to be 0.9 seconds. 
     The first time may be set to be different from the third time, and the second time may be set to be different from the fourth time. 
     The predetermined RPM may be at least 500 RPM or more at the time of stirring the pulsator from side to side. 
     The method may further include changing the motor RPM at the time of stirring the pulsator from side to side. 
     The method may further include changing a motor driving time or a motor stopping time at the time of stirring the pulsator from side to side. 
     The method may further include detecting a weight of the cloth; and changing the motor RPM according to the detected weight of the cloth. 
     The method may further include detecting the weight of the cloth; and changing the motor driving time or the motor stopping time according to the detected weight of the cloth. 
     The balance cycle may be carried out before a spin-drying cycle of the washing machine. 
     The method may further include counting the number of operating times of stirring the pulsator from side to side; comparing the counted number of times of stirring with a defined reference number of times of stirring; and stopping the stirring operation of the pulsator from side to side when the number of times of stirring is the reference number of times of stirring or more. 
     The reference number of times of stirring may be at least one or more. 
     In accordance with another aspect of the present disclosure, a method of controlling a washing machine including a washing tub accommodating cloth and a motor rotating the washing tub, includes (A) rotating the washing tub in one direction for a fifth time before supplying water to the washing tub; (B) stopping the washing tub for a sixth time after the washing tub rotates in one direction; (C) rotating the washing tub in an opposite direction for a seventh time when the sixth time elapses; and (D) stopping the washing tub for an eighth time after the washing tub rotates in the opposite direction, wherein a balance cycle may be carried out by performing a stirring operation of the washing tub configured of operations (A) to (D) from side to side at least once or more so as to uniformly distribute the cloth. 
     The fifth time may be set to be equal to the seventh time, and the sixth time may be set to be equal to the eighth time. 
     The fifth time may be set to be shorter than the sixth time, the fifth time may be set to be 1.9 seconds, and the sixth time may be set to be 2 seconds. 
     The fifth time may be set to be different from the seventh time, and the sixth time may be set to be different from the eighth time. 
     The motor RPM may be at least 150 RPM or more at the time of stirring the washing tub from side to side. 
     In accordance with another aspect of the present disclosure, a washing machine includes a washing tub configured to accommodate cloth; a pulsator rotatably installed in the washing tub; a motor configured to rotate the pulsator; and a controller configured to carry out a balance cycle controlling the motor before supplying water to the washing tub to stir the pulsator from side to side, and count the number of times of stirring of the pulsator to stop the stirring operation of the pulsator from side to side when the counted number reaches a defined reference number of times of stirring. 
     The controller may drive the motor at a predetermined RPM and an operating rate at the time of stirring the pulsator from side to side. 
     The controller may maintain the motor RPM at least at 500 RPM or more to strongly stir and rotate the pulsator. 
     The controller may set off time of the operating rate of the motor to be shorter than on time thereof at the time of stirring and rotating the pulsator so as to introduce an air layer between the cloths. 
     The controller may detect a weight of the cloth and control the motor RPM according to the detected weight of the cloth. 
     The controller may detect the weight of the cloth and change the operating rate of the motor according to the detected weight of the cloth. 
     In accordance with another aspect of the present disclosure, a washing machine includes a washing tub configured to accommodate cloth; a motor configured to rotate the washing tub; and a controller configured to carry out a balance cycle controlling the motor before supplying water to the washing tub to stir the washing tub from side to side, and count the number of times of stirring of the washing tub to stop the stirring operation of the washing tub from side to side when the counted number reaches a defined reference number of times of stirring. 
     The controller may drive the motor at a predetermined RPM and an operating rate at the time of stirring the washing tub from side to side. 
     The controller may maintain the motor RPM at least at 150 RPM or more to strongly stir and rotate the washing tub. 
     The controller may set on time of the operating rate of the motor to be shorter than off time thereof at the time of stirring and rotating the washing tub so as to introduce an air layer between the cloths. 
     The controller may detect a weight of the cloth and control the motor RPM according to the detected weight of the cloth. 
     The controller may detect the weight of the cloth and change the operating rate of the motor according to the detected weight of the cloth. 
     In accordance with another aspect of the present disclosure, a method of controlling a washing machine including a washing tub accommodating cloth and a pulsator rotatably installed in the washing tub, includes supplying water to the washing tub for washing; and rotating the pulsator to perform washing after supplying water, wherein a balance cycle may be carried out by stirring the pulsator from side to side so as to uniformly distribute the cloth before supplying water to the washing tub. 
     The stirring of the pulsator from side to side may include rotating the pulsator in one direction for a first time; stopping the pulsator for a second time after the pulsator rotates in one direction; rotating the pulsator in an opposite direction for the first time when the second time elapses; and stopping the pulsator for the second time after the pulsator rotates in the opposite direction. 
     The method may further include rotating the pulsator by a motor, wherein the pulsator may be driven in a forward direction or a backward direction for the first time while maintaining the motor at a predetermined RPM during the stirring of the pulsator from side to side. 
     The method may further include detecting a weight of the cloth before supplying water to the washing tub, and the balance cycle may be carried out after the weight of the cloth is detected. 
     The detecting of the weight of the cloth may be performed using a time taken for the motor to reach a predetermined duty while the motor is running at a weight detection RPM. 
     The predetermined RPM may have a value different from the weight detection RPM. 
     The predetermined RPM may have a value larger than the weight detection RPM. 
     The number of times of stirring may have a value larger than the number of times of weight detection. 
     In accordance with another aspect of the present disclosure, a method of controlling a washing machine including a washing tub accommodating cloth and a pulsator rotatably installed in the washing tub, includes supplying water to the washing tub for washing; and rotating the pulsator to perform washing after supplying water, wherein a balance cycle may be carried out by stirring the washing tub from side to side so as to uniformly distribute the cloth before supplying water to the washing tub. 
     The stirring of the pulsator from side to side may include rotating the washing tub in one direction for a fifth time; stopping the washing tub for a sixth time after the washing tub rotates in one direction; rotating the washing tub in an opposite direction for the fifth time when the sixth time elapses; and stopping the washing tub for the sixth time after the washing tub rotates in the opposite direction. 
     The method may further include counting the number of operating times of stirring the washing tub from side to side; comparing the counted number of times of stirring with a defined reference number of times of stirring; and stopping the operation of stirring the washing tub from side to side when the number of times of stirring is the reference number of times of stirring or more. 
     The method may further include rotating the pulsator by a motor, wherein the washing tub may be driven in a forward direction or a backward direction for the fifth time while maintaining the motor at a predetermined RPM during the stirring of the washing tub from side to side. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects of the disclosure will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG. 1  is a sectional view illustrating the configuration of a washing machine according to one embodiment of the present disclosure; 
         FIG. 2  is a block diagram illustrating control of the washing machine according to one embodiment of the present disclosure; 
         FIG. 3  is a flow chart illustrating the operation sequence of a control method of the washing machine according to one embodiment of the present disclosure; 
         FIG. 4  is a view illustrating an unbalanced state of cloth when a balance cycle is not carried out in the washing machine according to one embodiment of the present disclosure; 
         FIG. 5  is a view illustrating a balanced state of cloth when the balance cycle is carried out in the washing machine according to one embodiment of the present disclosure; 
         FIG. 6  is a flow chart illustrating the operation sequence in the balance cycle of the washing machine according to one embodiment of the present disclosure; 
         FIG. 7  is a view illustrating the distributed state of cloth before the balance cycle in the washing machine according to one embodiment of the present disclosure; 
         FIG. 8  is a view illustrating the distributed state of cloth after the balance cycle in the washing machine according to one embodiment of the present disclosure; 
         FIG. 9  is a graph illustrating a driving profile  1  of a motor in the balance cycle of the washing machine according to one embodiment of the present disclosure; 
         FIG. 10  is a graph illustrating a driving profile  2  of the motor in the balance cycle of the washing machine according to one embodiment of the present disclosure; 
         FIG. 11  is a graph illustrating a driving profile  3  of the motor in the balance cycle of the washing machine according to one embodiment of the present disclosure; 
         FIG. 12  is a graph illustrating a driving profile  4  of the motor in the balance cycle of the washing machine according to one embodiment of the present disclosure; 
         FIG. 13  is a graph illustrating a driving profile  5  of the motor in the balance cycle of the washing machine according to one embodiment of the present disclosure; 
         FIG. 14  is a graph illustrating a driving profile  6  of the motor in the balance cycle of the washing machine according to one embodiment of the present disclosure; 
         FIG. 15  is a graph illustrating a driving profile  7  of the motor in the balance cycle of the washing machine according to one embodiment of the present disclosure; 
         FIG. 16  is a flow chart illustrating the operation sequence in a balance cycle of a washing machine according another embodiment of the present disclosure; 
         FIG. 17  is a graph illustrating a driving profile  8  of a motor in the balance cycle of a washing machine according to another embodiment of the present disclosure; 
         FIG. 18  is a graph illustrating a driving profile  9  of the motor in the balance cycle of the washing machine according to another embodiment of the present disclosure; 
         FIG. 19  is a graph illustrating a driving profile  10  of the motor in the balance cycle of the washing machine according to another embodiment of the present disclosure; 
         FIG. 20  is a graph illustrating a driving profile  11  of the motor in the balance cycle of the washing machine according to another embodiment of the present disclosure; 
         FIG. 21  is a graph illustrating a driving profile  12  of the motor in the balance cycle of the washing machine according to another embodiment of the present disclosure; 
         FIG. 22  is a graph illustrating a driving profile  13  of the motor in the balance cycle of the washing machine according to another embodiment of the present disclosure; 
         FIG. 23  is a graph illustrating a driving profile  14  of the motor in the balance cycle of the washing machine according to another embodiment of the present disclosure; and 
         FIGS. 24A to 24G  are views illustrating states in which an angle of rotation of the washing tub making six rotations according to the motor driving profile in the balance cycle of the washing machine according to the embodiment of the present disclosure is measured. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
       FIG. 1  is a sectional view illustrating the configuration of a washing machine according to one embodiment of the present disclosure. 
     Referring to  FIG. 1 , a washing machine  1  according to one embodiment of the present disclosure has substantially a box shape and includes a body  10  forming the appearance thereof, a water tank  11  installed in the body  10  to store water (wash water or rinse water), a washing tub  12  rotatably installed in the water tank  11  to accommodate cloth, and a pulsator  13  which is rotatably installed in the washing tub  12  and makes left or right rotation (forward rotation or backward rotation) to generate water current, and has a vertical axis. 
     A motor  14  which generates a driving force for rotating the washing tub  12  and the pulsator  13 , and a power switching device  15  which transmits the driving force generated from the motor  14  simultaneously or selectively to the washing tub  12  and the pulsator  13  are installed on the bottom outside of the water tank  11 . 
     The motor  14  is a direct drive (DD) motor having a variable speed function, and this motor  14  transmits the driving force to the washing tub  12  or the pulsator  13  selectively according to the lifting and lowering motion of the power switching device  15 . A hollow spin-drying shaft  16  is joined to the bottom of the washing tub  12 , and a washing shaft  17  is installed in a hollow portion of the spin-drying shaft  16 , which passes through the water tank  11  and the spin-drying shaft  16  to be connected to the pulsator  13 . 
     For the motor  14 , a universal motor composed of field coils and an armature or a brushless direct motor (BLDC) motor composed of permanent magnets and electric magnets may be used. However, any motor  14  may be used as long as it can be applied to the washing machine  1 . Further, the motor  14  may be constituted in a belt type structure. 
     A water level sensor  18  which detects the frequency varying according to the water level to detect the volume (level) of the water in the water tank  11  is installed in the lower inside of the water tank  11 . 
     Further, a water supply valve  19  and a detergent box  20  for supplying water and detergent to the water tank  11  are installed above the water tank  11 , and the water supply valve  19  is installed midway along a water supply pipe  21  that supplies water into the water tank  11  to adjust water supply. A drain valve  22  and a drain pipe  23  for draining the water in the water tank  11  are installed below the water tank  11 . 
       FIG. 2  is a block diagram illustrating control of the washing machine according to one embodiment of the present disclosure. 
     Referring to  FIG. 2 , the washing machine  1  according to one embodiment of the present disclosure includes an input unit  50 , a controller  52 , a memory  54 , a driving unit  56  and a display unit  58 . 
     The input unit  50  is for the user to input the commands for executing the washing cycle, rinsing cycle and spin-drying cycle of the washing machine  1  through manipulation and may include keys, buttons, switches, touch pads, or the like and includes all devices that generate predetermined input data by the manipulation of pushing, touching, pressing and rotating. 
     Further, the input unit  50  includes a plurality of buttons (power, reservation, wash water temperature, soaking, rinsing, spin-drying, type of detergent, etc.) for inputting user commands related to the operation of the washing machine  1 . 
     The controller  52  serves as a microcomputer which controls the overall operation of the washing machine  1  such as washing, rinsing and spin-drying according to the operation information input from the input unit  50 , and sets a wash and rinse water amount, target RPM and a motor operating rate (motor on-off time), and washing and rinsing time according to the weight (load) of cloth in the selected washing course. 
     Further, the controller  52  carries out a balance cycle of strongly stirring and rotating the washing tub  12  or the pulsator  13  so as to uniformly distribute the cloth in the washing tub  12 , before supplying the set water according to the load (weight of cloth) after the cloth is put in. 
     At this time, the controller  52  adjusts motor RPM differently in the balance cycle whether the driving force of the motor  14  is transmitted to the washing tub  12  or the pulsator  13 . 
     This is because the rotation RPM of the washing tub  12  becomes remarkably lower than the motor RPM since the motor RPM is decelerated and transmitted to the pulsator  13  when the driving force of the motor  14  is transmitted to the pulsator  13 , whereas when the driving force of the motor  14  is transmitted to the washing tub  12 , the motor RPM is transmitted to the washing tub  12  as it is, so that the motor RPM is similar to the rotation RPM of the washing tub  12 . 
     Therefore, when the cloth is put in the washing tub  12  in the balance cycle in which the pulsator  13  is strongly stirred and rotated, the motor  14  is driven at a predetermined RPM (about 600 RPM) and an operating rate (1.4 seconds on/0.9 seconds off) to rotate the pulsator  13  strongly, in a dried-cloth state before supplying water for washing of cloth, so that the cloth is made to be distributed uniformly in the washing tub  12 . Thus, vibration and noise generated in the next spin-drying cycle are reduced. 
     Further, when the cloth is put in the washing tub  12  in the balance cycle in which the washing tub  12  is strongly stirred and rotated, the motor  14  is driven at a predetermined RPM (about 200 RPM) and an operating rate (1.9 seconds on/2 seconds off) to rotate the washing tub  12  strongly, in the dried-cloth state before supplying water for washing of cloth, so that the cloth is made to be distributed uniformly in the washing tub  12 . Thus, vibration and noise generated in the following spin-drying cycle are reduced. 
     The memory  54  can store control data for controlling the operations of the washing machine  1 , reference data used in control of the operations of the washing machine  1 , operation data generated while the washing machine  1  is performing a predetermined operation, setting information such as setting data input by the input unit  50  for the washing machine  1  to perform a predetermined operation, working information including the number of times that the washing machine  1  performed a specific operation and model information of the washing machine  1 , and failure information including the cause of malfunction or the location of malfunction in case of malfunction of the washing machine  1 . 
     The driving unit  56  drives the motor  14 , the water supply valve  19 , the drain valve  22 , and the like related to the operation of the washing machine  1  according to the driving control signals of the controller  52 . 
     The display unit  58  displays the operation state of the washing machine  1  and the manipulation state of the user according to the display control signals of the controller  52 . 
     Next, the operation processes and operation effects of the washing machine according to one embodiment of the present disclosure and a control method thereof will be described. 
       FIG. 3  is a flow chart illustrating the operation sequence of the control method of the washing machine according to one embodiment of the present disclosure, and it relates to an algorithm whereby vibration and noise can be reliably reduced in the spin-drying cycle by making distribution of the cloth uniform through powerful rotation of the pulsator  13  after the cloth is put in. 
     Referring to  FIG. 3 , when a user puts cloth in the washing tub  12  and inputs the operation information related to the washing course (a plurality of washing courses include a standard course, a wool course, fine course, etc., and for example, a standard course selected by the user according to the type of cloth) and the operation of the washing machine, the operation information selected by the user is input into the controller  52  through the input unit  50 . 
     Accordingly, the controller  52  detects the weight (load) of cloth that is put into the washing tub  12  for carrying out the washing cycle ( 100 ). For the method of detecting the weight of cloth, it is possible to employ any one method of a method including applying a predetermined duty (90 V) to the motor  14  while the motor  14  is rotating at a weight detection RPM (about 70 to 150 RPM), and measuring a time taken until the motor reaches a predetermined duty, and then detecting the weight using the measured time and a value of angular velocity thereof; a method in which the weight is detected using instantaneous acceleration of the motor  14  and a time taken until the motor reaches a predetermined velocity (or predetermined RPM); and a method including applying a torque to the motor  14  for a predetermined time, and measuring the inertia quantity of the washing tub  12  directly or indirectly, and then detecting the weight using the second law of motion (torque=inertial moment×angular velocity), as disclosed in Japanese Patent Publication Nos. 2002-336593, 2004-267334, and H07-90077. 
     Further, it is also possible to detect the weight (load) of cloth by using a load cell according to conventionally known methods. 
     Once the weight (load) of cloth is detected, the controller  52  sets the motor RPM and the operating rate (motor on-off time), target wash water level and target rinse water level, washing and rinsing time, etc. 
     Setting the motor RPM and the operating rate (motor on-off time), target wash water level and target rinse water level, washing and rinsing time, etc. corresponds to a case that the user does not additionally input a separate command related to the operation of the washing machine  1 . Of course, when the user additionally inputs a separate command related to the operation of the washing machine  1 , the motor RPM and the operating rate (motor on-off time) which are set according to the weight (load) of cloth, target wash water level and target rinse water level, washing and rinsing time, etc. are changed according to the user command. 
     After this, the controller  52  should supply the water (wash water) as set according to the weight (load) of cloth or the user command. At this time, the controller  52  carries out the balance cycle so that the cloth is distributed uniformly in the washing tub  12  before supplying water ( 102 ). 
     When a high water level is detected, that is, when a large weight (load) of cloth is detected, the balance cycle for the weight (load) of cloth is carried out. The weight (load) of cloth is classified largely into a low water level, a medium water level and a high water level. In the case of a low water level in which the weight (load) of cloth is small, vibration and noise are not generated much even if the spin-drying cycle proceeds in an unbalanced state in which the cloth is not distributed uniformly in the washing tub  12 , so the balance cycle need not be added. However, in the case of a high water level in which the weight (load) of cloth is large, if the spin-drying cycle is carried out in an unbalanced state in which the cloth is not distributed uniformly in the washing tub  12 , a great deal of vibration and noise are generated, so the balance cycle should be added. Therefore, in one embodiment of the present disclosure, the case in which the weight (load) of cloth is of at least medium water level or more will be described as an example of carrying out the balance cycle. 
     In general, the washing machine  1  is an apparatus in which washing is carried out using the floating of cloth and the water current generated by the rotation of the washing tub  12  driven by the motor  14 . Since the washing tub  12  rotates at a high speed of 700 to 1000 RPM in the spin-drying cycle, vibration and noise are generated. Such vibration and noise during the spin-drying cycle vary greatly according to the distribution of the cloth immediately before the spin-drying cycle. If the washing tub  12  is rotated at a high speed in an unbalanced state in which the cloth is not distributed uniformly in the washing tub  12 , a biased force is applied to the rotation shaft of the washing tub  12  to cause it to make eccentric movement, which causes large vibration and noise. 
     The distribution of the cloth is affected from the time when the user puts cloth in the washing tub  12 . The method of putting in cloth is considerably varied from user to user, so it is difficult to standardize it. Moreover, in a situation in which water usage diminishes by degrees as energy specification competition becomes fiercer, the importance of distribution resulting from the input of cloth increases enough to affect the vibration and/or noise performance of the washing machine  1 . If the distribution of the cloth is uniform, the vibration and/or noise level during the spin-drying cycle is low, which results in a high user satisfaction. On the other hand, if the distribution of the cloth is not uniform and unbalance is caused, the vibration and/or noise level during the spin-drying cycle is high enough to decrease user satisfaction and therefore also the marketable value of the washing machine. 
     Thus, the present disclosure lets cloth be distributed uniformly in the washing tub  12 , so that not only can it reduce unbalance during the spin-drying cycle, but it also carries out a balance cycle that can improve washing performance as well during the washing cycle. 
     For the balance cycle, there are a method in which the cloth in the washing tub  12  is distributed uniformly by strongly stirring and rotating the pulsator  13 , and another method in which the cloth in the washing tub  12  is distributed uniformly by strongly stirring and rotating the washing tub  12 . 
     First, in the balance cycle in which the pulsator  13  is strongly stirred and rotated, the motor  14  is driven at an operating rate of 1.4 seconds motor on/0.9 seconds motor off while maintaining the motor at a predetermined RPM (about 600 RPM at which the pulsator can be rotated strongly) to stir the pulsator  13  strongly from side to side by connecting the pulsator  13  to the washing shaft  17  of the motor  14 , in the dried-cloth state before supplying water to the washing tub  12 . Accordingly, the cloth piled up randomly in the washing tub  12  is loosened, so that the cloth is distributed uniformly in the washing tub  12 . 
     Next, in the balance cycle in which the washing tub  12  is strongly stirred and rotated, the motor  14  is driven at an operating rate of 1.9 seconds motor on/2 seconds motor off while maintaining the motor at a predetermined RPM (about 200 RPM at which the washing tub can be rotated strongly) to stir the pulsator  13  strongly from side to side by connecting the washing tub  12  to the spin-drying shaft  16  of the motor  14 , in the dried-cloth state before supplying water to the washing tub  12 . Accordingly, the cloth piled up randomly in the washing tub  12  is loosened, so that the cloth is distributed uniformly in the washing tub  12 . 
     Such a balance cycle lets detergent mix with water well by shaking detergent as cloth is moving when the cloth is shaken to be loosened even when the user puts detergent directly in cloth without putting detergent into the detergent box  20 . Thus, washing performance can be improved since detergent does not remain in the cloth during the washing cycle. 
     To describe this more specifically, the method of putting detergent varies from user to user like the method of putting in cloth. One user may put detergent directly into the detergent box, and another user may put detergent directly onto the cloth. Even in the case of putting detergent directly onto the cloth, the method of putting it in is different from user to user. For example, one user may sprinkle detergent uniformly on the cloth, while other users may pour detergent on one place of the cloth. Of these, when detergent is poured on one place of the cloth, the detergent can remain in the cloth or remain agglomerated sometimes. However, in one embodiment of the present disclosure, the detergent put onto the cloth is loosened as well when the cloth is shaken using the balance cycle, no matter how the detergent was put in by the user. Thus, the detergent mixes well with the water put in later and does not remain in the cloth after the washing cycle. 
     When the cloth (or detergent) is distributed uniformly in the washing tub  12  through the balance cycle like above, the controller  52  operates the water supply valve  19  to supply water (wash water) necessary for the washing cycle. 
     When the water supply valve  19  is operated, the water supply valve  19  is opened and water (wash water) passes through the detergent box  20  and the water supply pipe  21  to be supplied to the water tank  11  together with detergent ( 104 ). 
     Accordingly, the controller  52  detects the water level of the water supplied to the water tank  11  through the water level sensor  18  to determine whether it is a target wash water level (a water level determined according to the set quantity of wash water), and continues a water supply operation until the water supplied to the water tank  11  reaches the target wash water level. 
     When wash water supply is completed at the target wash water level, the controller  52  drives the motor  14  at the target RPM and the operating rate (motor on-off time) that were set for the washing cycle, to stir the pulsator  13  from side to side, and carries out the washing cycle by generating water current that transmits detergent water (wash water+detergent) to the cloth ( 106 ). 
     When washing is completed in the set washing time, the controller  52  stops the motor  14  and drains the detergent water (wash water+detergent) ( 108 ) before carrying out the intermediate spin-drying ( 110 ). 
     Then, the controller  52  operates the water supply valve  19  to supply water (rinse water) necessary for the rinsing cycle. 
     When the water supply valve  19  is operated, the water supply valve  19  is opened and water (rinse water) passes through the water supply pipe  21  to be supplied to the water tank  11  ( 112 ). At this time, the controller  52  controls water supply operation by stirred water supply whereby rinse water is supplied while the pulsator  13  is stirred from side to side for the improvement of rinse performance. Thereby, it is possible for the cloth stuck to the washing tub  12  due to the immediate spin-drying after the washing cycle to drop and mix well with water, and accordingly it is possible to obtain the effect of improved rinsing performance. 
     Thus, the controller  52  detects the water level of the water supplied to the water tank  11  through the water level sensor  18 , determines whether the detected water level is a target rinse water level (a water level determined according to the set quantity of rinse water), and continues water supply operation until the water level of the water supplied to the water tank  11  reaches the target rinse water level. 
     When rinse water supply is completed to the target rinse water level, the controller  52  drives the motor  14  at the target RPM and the operating rate (motor on-off time) that is set for the rinsing cycle, to stir the pulsator  13  from side to side, so that water current is generated to carry out the rinsing cycle in which water (rinse water) comes into contact with the cloth ( 114 ). 
     When rinsing is completed in the set rinsing time, the controller  52  stops the motor  14  and drains water (rinse water) ( 116 ). Such rinsing cycle is repeatedly carried out as many times as set. 
     When the last rinsing is completed after the rinsing cycle is carried out as many times as set, the controller  52  determines whether or not it is the spin-drying cycle ( 118 ). 
     If it is determined in operation  118  not to be the spin-drying cycle, the controller  52  carries out the intermediate spin-drying ( 120 ), and then feeds back to operation  112  and carries out the following operation. 
     On the other hand, If it is determined in operation  118  to be the spin-drying cycle, the controller  52  carries out the spin-drying cycle at the set final spin-drying RPM (about 700 to 1000 RPM) ( 122 ). 
     At this time, the present disclosure carries out the spin-drying cycle in a state in which the cloth is distributed uniformly in the washing tub  12 , so it is possible to reliably reduce frame vibration and spin-drying noise. 
     In the case in which the balance cycle is carried out and the case in which it is not carried out, the distribution states of cloth after spin-drying cycle are illustrated in  FIGS. 4 and 5 . 
       FIG. 4  is a view illustrating an unbalanced state of cloth when a balance cycle is not carried out in the washing machine according to one embodiment of the present disclosure, and  FIG. 5  is a view illustrating a balanced state of cloth when the balance cycle is carried out in the washing machine according to one embodiment of the present disclosure. 
     As shown in  FIG. 4 , it can be seen that cloth W is not distributed uniformly in the washing tub  12  because unbalance occurs when the balance cycle is not carried out. If unbalance occurs, the vibration and/or noise level increases during the spin-drying cycle, so the marketable value decreases. 
     On the other hand, as shown in  FIG. 5 , it can be seen that cloth W is distributed uniformly in the washing tub  12  when the balance cycle is carried out. If the cloth W is distributed uniformly, the vibration and/or noise level during the spin-drying cycle decreases, so the marketable value increases. 
     Next, the process of an algorithm of the balance cycle will be described with reference to  FIGS. 6 to 15 . 
       FIG. 6  is a flow chart illustrating the operation sequence in the balance cycle of the washing machine according to one embodiment of the present disclosure,  FIG. 7  is a view illustrating the distributed state of cloth before the balance cycle in the washing machine according to one embodiment of the present disclosure,  FIG. 8  is a view illustrating the distributed state of cloth after the balance cycle in the washing machine according to one embodiment of the present disclosure, and  FIG. 9  is a graph illustrating a driving profile  1  of a motor in the balance cycle of the washing machine according to one embodiment of the present disclosure. 
     First, when the user puts the cloth W into the washing tub  12 , the distribution of the cloth W put into the washing tub  12  is random as shown in  FIG. 7 , because the input method of cloth W varies from user to user. 
     With the cloth W piled up randomly in the washing tub  12 , the controller  52  connects the pulsator  13  to the washing shaft  17  of the motor  14  through the power switching device  15  ( 200 ). Thereby, the driving force of the motor  14  is transmitted to the washing shaft  17  through the power switching device  15  so as to stir the pulsator  13  strongly from side to side at the motor RPM of balance cycle. 
     Then, as shown in  FIG. 9 , the controller  52  drives the motor  14  at an operating rate of 1.4 seconds motor on/0.9 seconds motor off while maintaining the motor at a predetermined RPM (about 600 RPM, hereinafter referred to as a “first balance RPM”) to start the balance cycle in which the pulsator  13  is strongly stirred from side to side. 
     For this, the controller  52  drives the motor  14  at the first balance RPM in a forward direction through the driving unit  56  ( 202 ), and then counts the time for driving the motor  14  at the first balance RPM in the forward direction to determine whether the counted time amounts to a predetermined first time (about 1.4 seconds) ( 204 ). 
     If it is determined in operation  204  that the forward direction driving time of the motor  14  does not amount to the first time, the controller  52  feeds back to operation  202  and carries out the following operation. 
     Likewise, if the motor  14  is driven in the forward direction for the first time (1.4 seconds) at the first balance RPM, the pulsator  13  rotates strongly in one direction. If a force is applied to the cloth that was piled up randomly in the washing tub  12  by the strong rotation of the pulsator  13 , the cloth moves, the cloth that was stuck to the pulsator  13  drops and an air layer is formed therein. 
     On the other hand, if it is determined in operation  204  that the forward direction driving time of the motor  14  amounts to the first time, the controller  52  stops the motor  14  through the driving unit  56  ( 206 ), and then counts the time for stopping the motor  14  to determine whether the counted time amounts to a predetermined second time (about 0.9 seconds) ( 208 ). 
     If it is determined in operation  208  that the stopping time of the motor  14  does not amount to the second time, the controller  52  feeds back to operation  206  and carries out the following operation. 
     Thus, if the motor  14  is stopped for the second time (0.9 seconds) after driving the motor  14  in the forward direction, the air layer formed on the side of the pulsator  13  is introduced between the cloths, and looseness for the cloth to move in a given shape is generated in the cloth. 
     On the other hand, if it is determined in operation  208  that the stopping time of the motor  14  amounts to the second time, the controller  52  drives the motor  14  in a backward direction at the first balance RPM through the driving unit  56  ( 208 ), and then counts the time for driving the motor  14  at the first balance RPM in the backward direction to determine whether the counted time amounts to the first time ( 212 ). 
     If it is determined in operation  212  that the backward direction driving time of the motor  14  does not amount to the first time, the controller  52  feeds back to operation  210  and carries out the following operation. 
     Likewise, if the motor  14  is driven at the first balance RPM for the first time (1.4 seconds) in the backward direction, the pulsator  13  rotates strongly in the opposite direction. At this time, if a force is applied to the cloth through a reaction force of the pulsator  13  rotating strongly in the opposite direction in a state in which the movement of the cloth has not ended, the cloth is moved and the cloth that was stuck to the pulsator  13  drops higher than before and a slightly larger air layer is formed therein. 
     On the other hand, if it is determined in operation  212  that the backward direction driving time of the motor  14  amounts to the first time, the controller  52  stops the motor  14  through the driving unit  56  ( 214 ), and then counts the time for stopping the motor  14  to determine whether the counted time amounts to the second time ( 216 ). 
     If it is determined in operation  216  that the stopping time of the motor  14  does not amount to the second time, the controller  52  feeds back to operation  214  and carries out the following operation. 
     Likewise, if the motor  14  is stopped for the second time (0.9 seconds) after the motor  14  is driven in the backward direction, the air layer formed on the side of the pulsator  13  is further introduced between the cloths, and looseness is generated in the cloth for it to move smoothly in a given shape (specifically, in a sunflower shape). This shows the same effect as a user shaking and loosening the cloth. 
     On the other hand, if it is determined in operation  216  that the stopping time of the motor  14  amounts to the second time, the controller  52  counts the number of times of side-to-side stirring (N; hereinafter referred to as the “number of times of stirring”) resulting from the forward direction and backward direction driving of the motor  14  ( 218 ). 
     Subsequently, the controller  52  determines whether the counted number of times of motor stirring (N) has reached a defined reference number of times of stirring (Ns; an optimal number of times for uniformly distributing the cloth by shaking and loosening the cloth piled up randomly in the washing tub) ( 220 ). 
     If it is determined in operation  220  that the number of times of motor stirring (N) has not reached the reference number of times of stirring (Ns), the controller  52  feeds back to operation  202  and drives the motor  14  in the forward direction and backward direction until it reaches the reference number of times of stirring to carry out the balance cycle in which the pulsator  13  is stirred strongly from side to side. 
     On the other hand, if it is determined in operation  220  that the number of times of motor stirring (N) has reached the reference number of times of stirring (Ns), the cloth W is distributed uniformly in the washing tub  12 , as shown in  FIG. 8 , and thereby the controller  52  ends the balance cycle. 
     Meanwhile, in one embodiment of the present disclosure, maintaining the motor RPM of the balance cycle at 600 RPM is described as an example. However, the present disclosure is not limited thereto, and as long as if the motor RPM of the balance cycle is maintained at least at 500 RPM or more, it is possible to achieve the same objects and effects of the present disclosure. 
     Further, in one embodiment of the present disclosure, as shown in  FIG. 9 , when stirring the pulsator  13  strongly from side to side about three times by driving the motor at an operating rate of 1.4 seconds motor on/0.9 seconds off while maintaining the motor RPM of the balance cycle at 600 RPM, maintaining the motor operating rate equal regardless of the number of times of side-to-side stirring is described as an example. However, the present disclosure is not limited thereto, and of course, it is possible to achieve the same objects and effects of the present disclosure even if the on or off time of the motor operating rate is changed according to the number of times of side-to-side stirring. This will be described with reference to  FIGS. 10 and 11 . 
     In  FIG. 10 , for a first (one time) side-to-side stirring, the pulsator  13  can be stirred strongly from side to side by driving the motor at an operating rate of 1.4 seconds motor on/0.9 seconds motor off while maintaining the motor RPM at 600 RPM; for second (two times) side-to-side stirrings, the pulsator  13  can be stirred strongly from side to side by driving the motor at an operating rate of 1.2 seconds motor on/0.9 seconds motor off while maintaining the motor RPM at 600 RPM; and for third (three times) side-to-side stirrings, the pulsator  13  can be stirred strongly from side to side by driving the motor at an operating rate of 1.0 second motor on/0.9 seconds motor off while maintaining the motor RPM at 600 RPM. 
     Likewise, the balance cycle, in which the cloth W is distributed uniformly in the washing tub  12 , is carried out by changing the on time of the motor operating rate according to the number of times of side-to-side stirring of the pulsator  13 . 
       FIG. 11  is a graph illustrating a driving profile  3  of the motor in the balance cycle of the washing machine according to one embodiment of the present disclosure. In  FIG. 11 , for the first (one time) side-to-side stirring, the pulsator  13  can be stirred strongly from side to side by driving the motor at an operating rate of 1.4 seconds motor on/0.9 seconds motor off while maintaining the motor RPM at 600 RPM; for the second (two times) side-to-side stirrings, the pulsator  13  can be stirred strongly from side to side by driving the motor at an operating rate of 1.2 seconds motor on/0.7 seconds motor off while maintaining the motor RPM at 600 RPM; and for the third (three times) side-to-side stirrings, the pulsator  13  can be stirred strongly from side to side by driving the motor at an operating rate of 1.0 second motor on/0.5 seconds motor off while maintaining the motor RPM at 600 RPM. 
     As mentioned above, the balance cycle, in which the cloth W is distributed uniformly in the washing tub  12 , is carried out by changing the on/off time of the motor operating rate according to the number of times of side-to-side stirring of the pulsator  13 . 
     Further, the present disclosure can change the motor RPM and the operating rate according to the weight (load) of cloth W. This will be described with reference to  FIGS. 12 to 15 . 
       FIG. 12  is a graph illustrating the motor driving profile  4  in the balance cycle of the washing machine according to one embodiment of the present disclosure, and shows an example of changing the motor operating rate when the weight (load) of cloth W is large compared with the motor driving profile  1  of  FIG. 9 . 
     In  FIG. 12 , when the pulsator  13  is stirred strongly from side to side about three times by driving the motor at an operating rate of 1.8 seconds motor on/1.1 seconds motor off while maintaining the motor RPM of the balance cycle at 600 RPM, a balance cycle in which the motor operating rate is maintained equal regardless of the number of times of side-to-side stirring is carried out. 
       FIG. 13  is a graph illustrating the motor driving profile  5  in the balance cycle of the washing machine according to one embodiment of the present disclosure, and shows an example of changing both the motor RPM and the operating rate when the weight (load) of cloth W is large compared with the motor driving profile  1  of  FIG. 9 . 
     In  FIG. 13 , when the pulsator  13  is stirred strongly from side to side about three times by driving the motor at an operating rate of 1.8 seconds motor on/1.1 seconds motor off while maintaining the motor RPM of the balance cycle at 700 RPM, the balance cycle in which the motor operating rate is maintained equal regardless of the number of times of side-to-side stirring is carried out. 
     That is, if it is assumed that the weight (load) of cloth W of the motor driving profile  1  of  FIG. 9  is the case of medium water level, the motor driving profiles of  FIGS. 12 and 13  correspond to the cases in which the weight (load) of cloth W is of high water level. 
     In  FIGS. 12 and 13 , when stirring the pulsator  13  strongly from side to side about three times by driving the motor at an operating rate of 1.8 seconds motor on/1.1 seconds off while maintaining the motor RPM of the balance cycle at 600 RPM or 700 RPM, maintaining the motor operating rate equal regardless of the number of times of side-to-side stirring is described as an example. However, the present disclosure is not limited thereto, and of course, it is possible to achieve the same objects and effects of the present disclosure even if the on or off time of the motor operating rate is changed according to the number of times of side-to-side stirring. 
       FIG. 14  is a graph illustrating the motor driving profile  6  in the balance cycle of the washing machine according to one embodiment of the present disclosure, and shows an example of changing the motor operating rate when the weight (load) of cloth W is small compared with the motor driving profile  1  of  FIG. 9 . 
     In  FIG. 14 , when the pulsator  13  is stirred strongly from side to side about three times by driving the motor at an operating rate of 1.0 second motor on/0.7 seconds motor off while maintaining the motor RPM of the balance cycle at 600 RPM, the balance cycle in which the motor operating rate is maintained equal regardless of the number of times of side-to-side stirring is carried out. 
       FIG. 15  is a graph illustrating the motor driving profile  7  in the balance cycle of the washing machine according to one embodiment of the present disclosure, and shows an example of changing both the motor RPM and the motor operating rate when the weight (load) of cloth W is small compared with the motor driving profile  1  of  FIG. 9 . 
     In  FIG. 15 , when the pulsator  13  is stirred strongly from side to side about three times by driving the motor at an operating rate of 1.0 second motor on/0.7 seconds motor off while maintaining the motor RPM of the balance cycle at 500 RPM, the balance cycle in which the motor operating rate is maintained equal regardless of the number of times of side-to-side stirring is carried out. 
     That is, if it is assumed that the weight (load) of cloth W of the motor driving profile  1  of  FIG. 9  is the case of medium water level, the motor driving profiles of  FIGS. 14 and 15  correspond to the cases in which the weight (load) of cloth W is of low water level. 
     In  FIGS. 14 and 15 , when stirring the pulsator  13  strongly from side to side about three times by driving the motor at an operating rate of 1.0 second motor on/0.7 seconds off while maintaining the motor RPM of the balance cycle at 600 RPM or 500 RPM, maintaining the motor operating rate equal regardless of the number of times of side-to-side stirring is described as an example. However, the present disclosure is not limited thereto, and of course, it is possible to achieve the same objects and effects of the present disclosure even if the on or off time of the motor operating rate is changed according to the number of times of side-to-side stirring. 
     Next, the process of an algorithm of the balance cycle will be described with reference to  FIGS. 16 to 23 . 
     First, because the method of putting the cloth W in varies from user to user, when the user puts the cloth W into the washing tub  12 , the distribution of the cloth W put into the washing tub  12  is random as shown in  FIG. 7 . 
     With the cloth W piled up randomly in the washing tub  12 , the controller  52  connects the washing tub  12  to the spin-drying shaft  16  of the motor  14  through the power switching device  15  ( 300 ). Thereby, the driving force of the motor  14  is transmitted to the spin-drying shaft  16  through the power switching device  15  to stir the washing tub  12  strongly from side to side at the motor RPM of the balance cycle. 
     Subsequently, as shown in  FIG. 17 , the controller  52  drives the motor  14  at an operating rate of 1.9 seconds motor on/2 seconds motor off while maintaining the motor at a predetermined RPM (about 200 RPM, hereinafter referred to as a “second balance RPM”) to start the balance cycle in which the pulsator  13  is strongly stirred from side to side. 
     For this, the controller  52  drives the motor  14  through the driving unit  56  at the second balance RPM in the forward direction ( 302 ), and then counts the time for driving the motor  14  at the second balance RPM in the forward direction to determine whether the counted time amounts to a predetermined fifth time (about 1.9 seconds) ( 304 ). 
     If it is determined in operation  304  that the forward direction driving time of the motor  14  does not amount to the fifth time, the controller  52  feeds back to operation  302  to carry out the following operation. 
     Likewise, when the motor  14  is driven in the forward direction for the fifth time (1.9 seconds) at the second balance RPM, the washing tub  12  is rotated strongly in one direction. If a force is applied to the cloth W piled up randomly in the washing tub  12  by the strong rotation of the washing tub  12 , the cloth is moved, the cloth that was stuck to the washing tub  12  drops and the air layer is formed therein. 
     On the other hand, if it is determined in operation  304  that the stopping time of the motor  14  amounts to the fifth time, the controller  52  stops the motor  14  through the driving unit  56  ( 306 ), and then counts the time for stopping the motor  14  to determine whether the counted time amounts to a predetermined sixth time (about 2 seconds) ( 308 ). 
     If it is determined in operation  308  that the stopping time of the motor  14  does not amount to the sixth time, the controller  52  feeds back to operation  306  to carry out the following operation. 
     Thus, if the motor  14  is stopped for the sixth time (2 seconds) after driving the motor  14  in the forward direction, the air layer formed on the side of the washing tub  12  is introduced between the cloths, and looseness for the cloth to move in a given shape is generated in the cloth. 
     On the other hand, if it is determined in operation  308  that the stopping time of the motor  14  amounts to the sixth time, the controller  52  drives the motor  14  through the driving unit  56  at the second balance RPM in the backward direction ( 310 ), and then counts the time for driving the motor  14  at the second balance RPM in the backward direction to determine whether the counted time amounts to the fifth time ( 312 ). 
     If it is determined in operation  312  that the backward direction driving time of the motor  14  does not amount to the fifth time, the controller  52  feeds back to operation  310  to carry out the following operation. 
     Likewise, when the motor  14  is driven at the second balance RPM for the fifth time (1.9 seconds) in the backward direction, the washing tub  12  rotates strongly in the opposite direction. At this time, if a force is applied to the cloth through the reaction force of the washing tub  12  rotating strongly in the opposite direction in a state in which the movement of the cloth has not ended, the cloth is moved and the cloth that was stuck to the washing tub  12  drops higher than before and a slightly larger air layer is formed therein. 
     On the other hand, if it is determined in operation  312  the backward direction driving time of the motor  14  amounts to the fifth time as a result of determination in operation  312 , the controller  52  stops the motor  14  through the driving unit  56  ( 314 ), and then counts the time for stopping the motor  14  to determine whether the sixth time has elapsed ( 316 ). 
     If it is determined in operation  316  that the stopping time of the motor  14  does not amount to the sixth time, the controller  52  feeds back to operation  314  and carries out the following operation. 
     Likewise, if the motor is stopped for the sixth time (2 seconds) after the motor is driven in the backward direction, the air layer formed on the side of the washing tub  12  is further introduced into the space in the cloth, so that looseness is generated in the cloth for it to move smoothly in a given shape (specifically, a sunflower shape). This shows the same effect as a user shaking the cloth. 
     On the other hand, if the stopping time of the motor  14  amount so the sixth time, the controller  52  counts the number of times of motor stirring (N) according to the forward direction and backward direction driving of the motor  14  ( 318 ). 
     Subsequently, the controller  52  determines whether the counted number of times of motor stirring (N) has reached a reference number of times of stirring (Ns; about three times) ( 320 ). 
     If it is determined in operation  320  that the number of times of motor stirring (N) does not reach the reference number of times of stirring (Ns), the controller  52  feeds back to operation  302 , and drives the motor  14  in the forward direction and backward direction until it reaches the reference number of times of stirring (Ns), and continues to carry out the balance cycle in which the washing tub  12  is stirred strongly from side to side. 
     On the other hand, if it is determined in operation  320  that the number of times of motor stirring (N) reaches the reference number of times of stirring (Ns), the cloth W is distributed uniformly in the washing tub  12 , as shown in  FIG. 8 , and thereby the controller  52  ends the balance cycle. 
     Meanwhile, in one embodiment of the present disclosure, maintaining the motor operating rate equal regardless of the number of times of side-to-side stirring when the washing tub  12  is stirred strongly from side to side about three times by driving the motor at an operating rate of 1.9 seconds on/2 seconds off, while maintaining the motor RPM of the balance cycle at 200 RPM, as shown in  FIG. 17 , is described as an example. However, the present disclosure is limited thereto, and of course, it is possible to achieve the same objects and effects of the present disclosure by changing the on or off time of the motor operating rate according to the number of times of side-to-side stirring. This will be described with reference to  FIGS. 18 and 19 . 
       FIG. 18  is a graph illustrating a driving profile  9  of the motor in the balance cycle of the washing machine according to another embodiment of the present disclosure. 
     In  FIG. 18 , for the first (one time) side-to-side stirring, the washing tub  12  can be stirred strongly from side to side by driving the motor at an operating rate of 1.9 seconds motor on/2 seconds motor off while maintaining the motor RPM at 200 RPM; for the second (two times) side-to-side stirrings, the washing tub  12  can be stirred strongly from side to side by driving the motor at an operating rate of 1.7 seconds motor on/2 seconds motor off while maintaining the motor RPM at 200 RPM; and for the third (three times) side-to-side stirrings, the washing tub  12  can be stirred strongly from side to side by driving the motor at an operating rate of 1.5 seconds motor on/2 seconds motor off while maintaining the motor RPM at 200 RPM. 
     Likewise, the balance cycle in which the cloth W is distributed uniformly in the washing tub  12  is carried out by changing the on time of the motor operating rate according to the number of times of side-to-side stirring of the washing tub  12 . 
       FIG. 19  is a graph illustrating a driving profile  10  of the motor in the balance cycle of the washing machine according to another embodiment of the present disclosure. 
     In  FIG. 19 , for the first (one time) side-to-side stirring, the washing tub  12  can be stirred strongly from side to side by driving the motor at an operating rate of 1.9 seconds motor on/2 seconds motor off while maintaining the motor RPM at 200 RPM; for the second (two times) side-to-side stirrings, the washing tub  12  can be stirred strongly from side to side by driving the motor at an operating rate of 1.7 seconds motor on/1.8 seconds motor off while maintaining the motor RPM at 200 RPM; and for the third (three times) side-to-side stirrings, the washing tub  12  can be stirred strongly from side to side by driving the motor at an operating rate of 1.5 second motor on/1.6 seconds motor off while maintaining the motor RPM at 200 RPM. 
     Likewise, the balance cycle in which the cloth W is distributed uniformly in the washing tub  12  is carried out by changing the on/off time of the motor operating rate according to the number of times of side-to-side stirring of the washing tub  12 . 
     Besides this, the present disclosure can change the motor RPM and the operating rate according to the weight (load) of cloth W. This will be described with reference to  FIGS. 20 to 23 . 
       FIG. 20  is a graph illustrating a driving profile  11  of the motor in the balance cycle of the washing machine according to another embodiment of the present disclosure, and shows an example of changing the motor operating rate when the weight (load) of cloth W is large compared with the driving profile  8  of  FIG. 17 . 
     In  FIG. 20 , when the washing tub  12  is stirred strongly from side to side about three times by driving the motor at an operating rate of 2.3 seconds motor on/2.4 seconds motor off while maintaining the motor RPM of the balance cycle at 200 RPM, the balance cycle in which the motor operating rate is maintained equal regardless of the number of times of side-to-side stirring is carried out. 
       FIG. 21  is a graph illustrating a driving profile  12  of the motor in the balance cycle of the washing machine according to another embodiment of the present disclosure, and shows an example of changing both the motor RPM and the operating rate when the weight (load) of cloth W is large compared with the driving profile  8  of  FIG. 17 . 
     In  FIG. 21 , when the washing tub  12  is stirred strongly from side to side about three times by driving the motor at an operating rate of 2.3 seconds motor on/2.4 seconds motor off while maintaining the motor RPM of the balance cycle at 250 RPM, the balance cycle in which the motor operating rate is maintained equal regardless of the number of times of side-to-side stirring is carried out. 
     That is, if it is assumed that the weight (load) of cloth W of the motor driving profile  1  of  FIG. 17  is the case of medium water level, the motor driving profiles of  FIGS. 20 and 21  correspond to the cases in which the weight (load) of cloth W is of high water level. 
     In  FIGS. 20 and 21 , maintaining the motor operating rate equal regardless of the number of times of side-to-side stirring when the washing tub  12  is stirred strongly from side to side about three times by driving the motor at an operating rate of 2.3 seconds on/2.4 seconds off, while maintaining the motor RPM of the balance cycle at 200 RPM or 250 RPM, is described as an example. However, the present disclosure is limited thereto, and of course, it is possible to achieve the same objects and effects of the present disclosure by changing the on or off time of the motor operating rate according to the number of times of side-to-side stirring. 
       FIG. 22  is a graph illustrating a driving profile  13  of the motor in the balance cycle of the washing machine according to another embodiment of the present disclosure, and shows an example of changing the operating rate when the weight (load) of cloth W is small compared with the driving profile  8  of  FIG. 17 . 
     In  FIG. 22 , when the washing tub  12  is stirred strongly from side to side about three times by driving the motor at an operating rate of 1.5 seconds motor on/1.6 seconds motor off while maintaining the motor RPM of the balance cycle at 200 RPM, the balance cycle in which the motor operating rate is maintained equal regardless of the number of times of side-to-side stirring is carried out. 
       FIG. 23  is a graph illustrating a driving profile  14  of the motor in the balance cycle of the washing machine according to another embodiment of the present disclosure, and shows an example of changing both the motor RPM and the operating rate when the weight (load) of cloth W is small compared with the driving profile  8  of  FIG. 17 . 
     In  FIG. 23 , when the washing tub  12  is stirred strongly from side to side about three times by driving the motor at an operating rate of 1.5 seconds motor on/1.6 seconds motor off while maintaining the motor RPM of the balance cycle at 150 RPM, the balance cycle in which the motor operating rate is maintained equal regardless of the number of times of side-to-side stirring is carried out. 
     That is, if it is assumed that the weight (load) of cloth W of the motor driving profile  1  of  FIG. 17  is the case of medium water level, the motor driving profiles of  FIGS. 22 and 23  correspond to the cases in which the weight (load) of cloth W is of low water level. 
     In  FIGS. 22 and 23 , maintaining the motor operating rate equal regardless of the number of times of side-to-side stirring when the washing tub  12  is stirred strongly from side to side about three times by driving the motor at an operating rate of 1.5 seconds on/1.6 seconds off while maintaining the motor RPM of the balance cycle at 200 RPM or 150 RPM is described as an example. However, the present disclosure is limited thereto, and of course, it is possible to achieve the same objects and effects of the present disclosure by changing the on or off time of the motor operating rate according to the number of times of side-to-side stirring. 
     Next, examples in which the angle of rotation of the washing tub  12  making six rotations is measured through any one of the motor driving profiles illustrated in  FIGS. 6 to 15  and  FIGS. 17 to 23  are illustrated in  FIGS. 24A to 24G . 
       FIG. 24A  is a view illustrating the state of the washing tub  12  before the balance cycle is started. 
       FIG. 24B  is a view illustrating the state of the washing tub  12  when the balance cycle is started and the motor has made one rotation in the forward direction, and it can be seen that the angle of rotation of the washing tub  12  is +270°. 
       FIG. 24C  is a view illustrating the state of the washing tub  12  when the motor  14  has made two rotations in the backward direction (that is, the motor has rotated again in the backward direction from the position after rotating in the forward direction), and it can be seen that the angle of rotation of the washing tub  12  is −145°. 
       FIG. 24D  is a view illustrating the state of the washing tub  12  when the motor  14  has made three rotations in the forward direction (that is, the motor has rotated again in the forward direction from the position after rotating in the backward direction), and it can be seen that the angle of rotation of the washing tub  12  is +195°. 
       FIG. 24E  is a view illustrating the state of the washing tub  12  when the motor  14  has made four rotations in the backward direction (that is, the motor has rotated again in the backward direction from the position after rotating in the forward direction), and it can be seen that the angle of rotation of the washing tub  12  is −150°. 
       FIG. 24F  is a view illustrating the state of the washing tub  12  when the motor  14  has made five rotations in the forward direction (that is, the motor has rotated again in the forward direction from the position after rotating in the backward direction), and it can be seen that the angle of rotation of the washing tub  12  is +150°. 
       FIG. 24G  is a view illustrating the state of the washing tub  12  when the motor  14  has made six rotations in the backward directions (that is, the motor has rotated again in the backward direction from the position after rotating in the forward direction), and it can be seen that the angle of rotation of the washing tub  12  is −145°. 
     As shown in  FIGS. 24A to 24G , the angle of rotation of the washing tub  12  is changed greatly by the forward or backward direction rotation of the motor  14 , and a force is applied to the cloth W in the washing tub  12  according to the changing angle of rotation of the washing tub  12 . Thus, the air layer is formed as the cloth W that was stuck to the pulsator  13  drops, which causes an effect of shaking the cloth W that is piled up randomly in the washing tub  12 . 
     Here, the examples of measuring the angle of rotation of the washing tub  12  that makes six rotations according to the motor driving profile in the balance cycle of the washing machine are listed in Table 1 below. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                   
                   
                   
                   
                 Six 
               
               
                   
                 One 
                 Two 
                 Three 
                 Four 
                 Five 
                 rota- 
               
               
                   
                 rotation 
                 rotations 
                 rotations 
                 rotations 
                 rotations 
                 tions 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Try 1 
                 +270° 
                 −145°  
                 +195° 
                 −150° 
                 +150° 
                 −145° 
               
               
                 Try 2 
                 +230° 
                 −70° 
                 +140° 
                 −165° 
                  +40° 
                 −175° 
               
               
                 Try 3 
                 +280° 
                 −50° 
                 +225° 
                 −105° 
                 +145° 
                 −110° 
               
               
                 Try 4 
                 +320° 
                 −120°  
                 +170° 
                 −210° 
                 +190° 
                 −170° 
               
               
                 Try 5 
                 +275° 
                 −65° 
                 +145° 
                 −100° 
                 +220° 
                 −130° 
               
               
                   
               
            
           
         
       
     
     As shown in Table 1, it can be seen that the angle of rotation of the washing tub  12  is changed greatly according to the forward direction or backward direction rotation of the motor  14 . 
     In accordance with the proposed washing machine and the control method thereof, cloth piled up randomly in the washing tub is shaken and loosened through the stirring from side to side of the pulsator or the washing tub before water is supplied after putting the cloth therein, so that distribution of the cloth is made uniform to reduce vibration and noise during the spin-drying cycle. Further, unsatisfactory spin-drying due to abnormal vibration is prevented so that it is possible to reduce unnecessary consumption of water and spin-drying time. Further, even when the user does not put detergent in the detergent box but puts it directly onto the cloth, the detergent is shaken by the movement of the cloth, so it is possible to improve washing performance as the detergent and water are mixed well. 
     Although a few embodiments of the present disclosure have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.