Washing machine and control method thereof

Abstract

A washing machine that can determine a weight of laundry in consideration of the result of determination on whether the laundry is dry cloth or wet cloth, and a control method of the washing machine. Before washing starts, a drum rotates to measure a changed amount in water level, and it is determined whether laundry is dry cloth or wet cloth based on the changed amount in water level. If it is determined that the laundry is wet cloth, a weight of the laundry is accurately detected by using wet cloth weight criteria or by adding a weight according to the changed amount in water level, which leads to reducing water consumption, a washing time, and energy consumption while preventing laundry from being damaged.

What is claimed is: 
     
         1 . A control method of a washing machine, the washing machine including a tub to accommodate water therein, and a drum rotatably installed in the tub and configured to accommodate laundry therein, the control method comprising:
 determining whether the washing machine starts operating;   rotating, if it is determined that the washing machine starts operating, the drum before supplying water to the tub;   measuring a changed amount in water level according to the rotation of the drum to determine whether the laundry is dry cloth or wet cloth; and   setting, if it is determined that the laundry is wet cloth, a washing condition corresponding to wet cloth.   
     
     
         2 . The control method according to  claim 1 , further comprising a washing motor configured to rotate the drum, wherein the rotating of the drum comprises rotating the washing motor at Revolution Per Minute (RPM) for dehydrating water contained in the laundry. 
     
     
         3 . The control method according to  claim 2 , wherein the RPM is equal to or more than 90 RPM. 
     
     
         4 . The control method according to  claim 1 , further comprising a water level sensor configured to measure a level of water loaded in the tub,
 wherein the determining of whether the laundry is dry cloth or wet cloth comprises:   measuring a level of water loaded in the tub using the water level sensor before rotating the drum;   measuring a level of water loaded in the tub using the water level sensor after rotating the drum; and   measuring a changed amount in water level by comparing the level of water measured before rotating the drum to the level of water measured after rotating the drum to determine whether the laundry is dry cloth or wet cloth.   
     
     
         5 . The control method according to  claim 4 , further comprising determining, if a changed amount in water level is measured, that the laundry is wet cloth. 
     
     
         6 . The control method according to  claim 4 , further comprising determining, if no changed amount in water level is measured, that the laundry is dry cloth. 
     
     
         7 . The control method according to  claim 1 , wherein the setting of the washing condition corresponding to wet cloth comprises determining a weight of the laundry using weight criteria that is different from weight criteria to be used when the laundry is dry cloth. 
     
     
         8 . The control method according to  claim 7 , wherein the washing machine further includes a washing motor configured to rotate the drum, and
 wherein the determining of the weight of the laundry comprises estimating a weight of the laundry using an acceleration time taken for the drum to reach a predetermined velocity when predetermined torque is applied to the washing motor.   
     
     
         9 . The control method according to  claim 7 , wherein the determining of the weight of the laundry comprises performing, if it is determined that the laundry is wet cloth, a wetting process to wet the laundry, and then estimating a weight of the laundry. 
     
     
         10 . The control method according to  claim 4 , wherein the determining of whether the laundry is dry cloth or wet cloth is performed before a water supply process of initially supplying water in order to wash the laundry. 
     
     
         11 . The control method according to  claim 4 , wherein the determining of whether the laundry is dry cloth or wet cloth is performed before determining the weight of the laundry. 
     
     
         12 . A washing machine comprising:
 a tub configured to accommodate water therein;   a drum rotatably installed in the tub and configured to accommodate laundry therein;   a washing motor configured to rotate the drum; and   a controller configured to control the washing motor to rotate the drum before supplying water to the tub, to measure a changed amount in water level according to the rotation of the drum, and to set a washing condition according to the changed amount in water level.   
     
     
         13 . The washing machine according to  claim 12 , wherein the controller rotates the drum at Revolution Per Minute (RPM) for dehydrating water contained in the laundry. 
     
     
         14 . The washing machine according to  claim 12 , further comprising a water level sensor configured to measure a level of water loaded in the tub,
 wherein the controller measures a level of water loaded in the tub using the water level sensor before rotating the drum, measures a level of water loaded in the tub using the water level sensor after rotating the drum, and measures a changed amount in water level by comparing the level of water measured before rotating the drum to the level of water measured after rotating the drum to determine whether the laundry is dry cloth or wet cloth.   
     
     
         15 . The washing machine according to  claim 14 , wherein if a changed amount in water level is measured, the controller determines that the laundry is wet cloth. 
     
     
         16 . The washing machine according to  claim 12 , wherein the controller determines a weight of the laundry using an acceleration time taken for the washing motor to reach a predetermined velocity when predetermined torque is applied to the washing motor. 
     
     
         17 . The washing machine according to  claim 16 , wherein if it is determined that the laundry is wet cloth, the controller performs a wetting process to wet the laundry before determining a weight of the laundry. 
     
     
         18 . The washing machine according to  claim 12 , wherein the controller determines whether the laundry is dry cloth or wet cloth according to the changed amount in water level, and determines a weight of the laundry using different weight criterion depending on whether the laundry is dry cloth or wet cloth. 
     
     
         19 . The washing machine according to  claim 16 , further comprising a memory having a wet cloth table and a dry cloth table,
 wherein the controller estimates the weight of the laundry using the wet cloth table or the dry cloth table corresponding to the acceleration time.   
     
     
         20 . The washing machine according to  claim 19 , wherein, when the controller utilizes the wet cloth table, the controller estimates the weight of the laundry using the wet cloth table after a adding a weight to the wet cloth table according to the changed amount in water level.