Patent ID: 8719985

Claim:
A control method of a washing machine comprising a water tub and a drum rotatably installed in the water tub, the method comprising: determining whether or not to perform a wetting stroke; rotating the drum upon determining to perform the wetting stroke; initially opening a water supply valve during rotation of the drum, to initially supply water into the water tub through a water supply path provided between the water tub and the drum so that the initially supplied water is prevented from being entered into the drum and being absorbed into laundry due to centrifugal force caused by the rotating of the drum; closing the water supply valve when the initially supplied water reaches a hydraulic pressure sensing water level which is a minimum water level required to sense hydraulic pressure; calculating an initial open time of the water supply valve until the initially supplied water reaches the hydraulic pressure sensing water level; estimating the hydraulic pressure of the water supplied to the washing machine based on the initial open time of the water supply valve; determining whether a variation in water level exists due to the wetting stroke; and opening the water supply valve to additionally supply water into the water tub if it is determined that the variation in water level exists and not opening the water supply level to stop the additionally supply water into the water tub if it is determined that the variation in water level does not exist, wherein the rotation of the drum begins prior to the initially opening of the water supply valve, and ends if it is determined that the variation in water level does not exist.