Washing machine and method for controlling the same

Abstract

A washing machine and a method of controlling the same are disclosed. If two washing tubs simultaneously perform the dehydration, unbalanced positions of the first and second washing tubs are checked. The method controls dehydration rotation speed or dehydration rotation direction of each washing tub to adjust a difference in unbalanced position angle between two washing tubs, thereby reducing vibration. If dehydration is performed in one washing tub, the method prevents the other washing tub performing no dehydration process from entering the dehydration process.

1 . A method of controlling a washing machine having a first washing tub and a second washing tub, the method comprising:
 determining whether a dehydration operation is performed in the first and second washing tubs; and   reducing vibration of the washing machine comprising adjusting the dehydration operation of the first or second washing tub.   
     
     
         2 . The method according to  claim 1 , wherein the determining whether the dehydration operation is performed in the first and second washing tubs includes:
 determining, when one of the first and second washing tubs is in the dehydration process, whether the other of the first and second washing tubs performing no dehydration operation begins a dehydration operation.   
     
     
         3 . The method according to  claim 2 , further comprising:
 controlling, if the other of the first and second washing tubs having no dehydration operation beings the dehydration operation, the dehydration operation of the other of the first and second washing tubs comprising performing a dehydration rotation in a direction opposite to a dehydration rotation direction of the one of the first and second washing tubs in which the dehydration operation is performed.   
     
     
         4 . The method according to  claim 2 , further comprising:
 controlling, if the other of the first and second washing tubs having no dehydration operation begins the dehydration operation, a dehydration operation of the other of the first and second washing tubs to prevent the other of the first and second washing tubs from entering the dehydration operation until the washing tub performing the dehydration operation stops the dehydration operation.   
     
     
         5 . The method according to  claim 1 , wherein the determining whether the dehydration process is performed in the first and second washing tubs includes:
 determining whether the first and second washing tubs simultaneously begin the dehydration operation.   
     
     
         6 . The method according to  claim 5 , further comprising:
 setting, if the first and second washing tubs simultaneously begin the dehydration operation, different dehydration rotation directions, so that the dehydration operations of the first and second washing tubs are performed in different directions.   
     
     
         7 . The method according to  claim 5 , further comprising:
 adjusting, if the first and second washing tubs simultaneously begin the dehydration operation, a dehydration operation of the washing tub in such a manner that the dehydration operation is performed only in one of the first and second washing tubs.   
     
     
         8 . The method according to  claim 7 , further comprising:
 adjusting a dehydration operation of the washing tub having no dehydration operation in such a manner that the washing tub having no dehydrating operation begins the dehydration operation when the dehydration operation of the washing tub having the dehydration operation is completed.   
     
     
         9 . The method according to  claim 1 , wherein the determining whether the dehydration process is performed in the first and second washing tubs includes:
 determining whether the first and second washing tubs simultaneously perform the dehydration operation.   
     
     
         10 . The method according to  claim 9 , further comprising:
 checking an unbalanced position of each of the first and second washing tubs when the first and second washing tubs simultaneously perform the dehydration operation.   
     
     
         11 . The method according to  claim 10 , wherein:
 a first drum is rotatably installed in the first washing tub, and a second drum is rotatably installed in the second washing tub, and   the checking of the unbalanced position comprises detecting a rotation speed of the first or second drum.   
     
     
         12 . The method according to  claim 11 , wherein the checking of the unbalanced position by detecting the rotation speed of the first or second drum includes:
 checking a position at which a rotational acceleration of the first or second drum becomes zero.   
     
     
         13 . The method according to  claim 12 , wherein the checking of the unbalanced position by detecting the rotation speed of the first or second drum further includes:
 determining that the unbalanced position is at a highest point of the first or second drum at a time at which the rotational acceleration becomes zero in response to an increasing and decreasing of the rotation speed of the first or second drum.   
     
     
         14 . The method according to  claim 13 , wherein the checking of the unbalanced position by detecting the rotation speed of the first or second drum further includes:
 determining that the unbalanced position is at a lowest point of the first or second drum at a time at which the rotation acceleration becomes zero in response to the increasing and decreasing of the rotation speed of the first or second drum.   
     
     
         15 . The method according to  claim 10 , further comprising:
 adjusting, if the unbalanced position of the first or second washing tub is checked, an unbalanced position of the first or second washing tub, and reducing the vibration of the washing machine.   
     
     
         16 . The method according to  claim 15 , wherein the adjusting of the unbalanced position of the first or second washing tub includes:
 controlling a difference between a first position angle of an unbalance of the first washing tub and a second position angle of an unbalance of the second washing tub to be equal to or larger than a reference angle.   
     
     
         17 . The method according to  claim 15 , wherein the adjusting of the unbalanced position of the first or second washing tub includes:
 adjusting the unbalanced position comprising adjusting a dehydration rotation speed of the first or second washing tub.   
     
     
         18 . The method according to  claim 9 , further comprising:
 setting, if the dehydration operation is simultaneously performed in the first and second washing tubs, different dehydration rotation directions to the first and second washing tubs, and adjusting the dehydration operations of each of the washing tubs.   
     
     
         19 . The method according to  claim 18 , further comprising:
 checking dehydration rotation speeds of the first and second washing tubs; and   changing the rotation direction of the washing tub having a relatively slow dehydration rotation speed from among the first and second washing tubs to another rotation direction, and adjusting the dehydration operation of the washing tub in the changed rotation direction.   
     
     
         20 . A washing machine comprising:
 a plurality of washing tubs; and   a controller which checks whether a dehydration operation is performed in each of the washing tubs, adjusts the dehydration operation of each of the washing tubs when the dehydration operation is performed in each of the washing tubs, and reduces a vibration of the washing machine.   
     
     
         21 . The washing machine according to  claim 20 , further comprising a first drum and a second drum wherein:
 the plurality of washing tubs include a first washing tub in which the first drum is rotatably installed and a second washing tub in which the second drum is rotatably installed, and the controller reduces vibration of the washing machine by adjusting rotation operations of the first and second drums.   
     
     
         22 . The washing machine according to  claim 21 , further comprising:
 a speed detector to detect a speed of the first or second drum.   
     
     
         23 . The washing machine according to  claim 22 , wherein the controller checks an unbalanced position of the first or second washing tub according to a speed of the first or second drum. 
     
     
         24 . The washing machine according to  claim 23 , wherein the controller reduces vibration of the washing machine by adjusting the unbalanced position of the first or second washing tub. 
     
     
         25 . The washing machine according to  claim 24 , wherein the controller adjusts a difference in the unbalanced position between the first washing tub and the second washing tub to be equal to or larger than a reference angle. 
     
     
         26 . The washing machine according to  claim 21 , wherein the controller reduces the vibration of the washing machine by controlling the first and second drums to have different dehydration rotation directions opposite to each other.