Patent ID: 8499391

Claim:
A method of controlling an operation of a laundry machine to treat laundry using a rotational force of a drum, comprising: judging hardness about a floor, on which the laundry machine is mounted; and controlling a rotational speed of the drum according to a hardness about the floor so as to treat the laundry, wherein the control of the rotational speed of the drum is performed upon dehydrating the laundry, wherein, if the hardness is between a first set hardness and a second set hardness, the dehydrating is performed in a general dehydrating operating state, wherein, if the hardness is more than the first set hardness, a maximum rotational speed of the drum is restricted to be less than a rotational speed of the drum in the general dehydrating operating state, and wherein, if the hardness is less than the second set hardness, the maximum rotational speed of the drum is set to be more than the rotational speed of the drum in the general dehydrating operating state and an operating time of the drum is restricted to be less than an operating time in the general dehydrating operating state.