# US 9,752,268 B2 · Control method of washing machine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,752,268 B2 - Document ID: US9752268B2 - Status: Granted - Kind: B2 - Application number: 14/601,877 - Filed: 2015-01-21 - Published: 2015-07-23 - Granted: 2017-09-05 - Earliest claimed: 2014-01-22 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Youngjong Kim; Sangjun Lee - Web page: https://patentgrep.com/patent/US9752268B2 ## CPC - D06F 37/304: {Arrangements or adaptations of electric motors} - D06F 33/30: Control of washing machines characterised by the purpose or target of the control (controlling processes of washer-dryers D06F33/50) - D06F 37/36: for rotating the receptacle at more than one speed {(D06F37/304, D06F37/308 take precedence)} - D06F 21/00: Washing machines with receptacles, e.g. perforated, having a rotary movement, e.g. oscillatory movement (with receptacles serving both for washing and centrifugally separating water from the laundry D06F23/00, D06F25/00; program-control aspects D06F33/00) - D06F 37/40: for driving the receptacle and an agitator or impeller, e.g. alternatively {(D06F37/304, D06F37/308 take precedence)} - D06F 2103/04: Quantity, e.g. weight or variation of weight - D06F 2103/46: of the motor driving the drum - D06F 2105/46: Drum speed; Actuation of motors, e.g. starting or interrupting - D06F 2105/54: Changing between normal operation mode and special operation modes, e.g. service mode, component cleaning mode or stand-by mode - Y02B 40/00: Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers - D06F: LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract A main motor is rotated at a predetermined target speed to determine whether a clutch has been normally operated during switching between a spin mode and an agitation mode. A current value sensed during rotation of the main motor is compared with a predetermined reference value to determine whether the clutch is normally operated. Mode switching is performed or the clutch is re-operated based on the determination result, thereby correctly performing switching between the spin mode and the agitation mode. ## Claims ### Claim 1 A control method of a washing machine comprising an inner tub, a pulsator rotatable in the inner tub, a main motor configured to rotate the pulsator, and a clutch configured to engage the inner tub with the main motor or disengage the inner tub from the main motor, the control method comprising: (a) executing a spin mode for driving the main motor in a state in which the inner tub is engaged with the main motor to rotate both the inner tub and the pulsator; (b) operating the clutch for execution of an agitation mode for driving the main motor in a state in which the inner tub is disengaged from the main motor to rotate the pulsator; (c) applying current to the main motor such that the main motor can be rotated at a predetermined target speed; (d) comparing a value of the current applied to the main motor with a predetermined reference value to determine whether the agitation mode can be executed; and (e) executing the agitation mode when a comparison result at step (d) indicates that the current value applied to the main motor is equal to or greater than the reference value, wherein step (b) is re-executed when the comparison result at step (d) indicates that the current value applied to the main motor is less than the reference value. ### Claim 2 (depends on 1) The control method according to claim 1, wherein steps (c), (d), and (e) are sequentially executed after step (b) is re-executed. ### Claim 3 (depends on 2) The control method according to claim 2, wherein steps (b), (c), (d), and (e) are repeatedly executed until the comparison result at step (d) indicates that the current value applied to the main motor is equal to or greater than the reference value, the control method further comprising outputting an error message through an error message output unit when the number of times of execution of step (b) exceeds a predetermined number of times. ### Claim 4 (depends on 1) The control method according to claim 1, wherein step (d) comprises comparing an average value of the current applied to the main motor with the reference value while a rotation of the main motor is maintained at a target speed. ### Claim 5 (depends on 1) The control method according to claim 1, wherein step (d) comprises comparing a maximum value of the current applied to the main motor with the reference value while a rotation of the main motor is maintained at a target speed. ### Claim 6 (depends on 1) The control method according to claim 1, wherein the reference value is set within a prescribed range equal to or greater than an average current value when a current is applied to the main motor for maintaining a rotation of the main motor at the target speed in a state in which the inner tub is engaged with the main motor and equal to or less than an average current value when the current is applied to the main motor for maintaining the rotation of the main motor at the target speed in a state in which the inner tub is disengaged from the main motor. ### Claim 7 (depends on 1) The control method according to claim 1, further comprising: sensing laundry weight; and setting the reference value based on the sensed laundry weight. ### Claim 8 (depends on 7) The control method according to claim 7, wherein the reference value is set to have a higher value as the laundry weight is increased. ### Claim 9 A control method of a washing machine comprising an inner tub, a pulsator rotatable in the inner tub, a main motor configured to rotate the pulsator, and a clutch configured to engage the inner tub with the main motor or disengage the inner tub from the main motor, the control method comprising: (a) executing an agitation mode for driving the main motor in a state in which the inner tub is disengaged from the main motor to rotate the pulsator; (b) operating the clutch for execution of a spin ode for driving the main motor in a state in which the inner tub is engaged with the main motor to rotate both the inner tub and the pulsator; (c) applying current to the main motor such that the main motor can be rotated at a predetermined target speed; (d) comparing a value of the current applied to the main motor with a predetermined reference value to determine whether the spin mode can be executed; and (e) executing the spin mode when a comparison result at step (d) indicates that the current value applied to the main motor is less than the reference value, wherein step (b) is re-executed when the comparison result at step (d) indicates that the current value applied to the main motor is equal to or greater than the reference value. ### Claim 10 (depends on 9) The control method according to claim 9, wherein steps (c), (d), and (e) are sequentially executed after step (b) is re-executed. ### Claim 11 (depends on 10) The control method according to claim 10, wherein steps (b), (c), (d), and (e) are repeatedly executed until the comparison result at step (d) indicates that the current value applied to the main motor is less than the reference value, the control method further comprising outputting an error message through an error message output unit when the number of times of execution of step (b) exceeds a predetermined number of times. ### Claim 12 (depends on 9) The control method according to claim 9, wherein step (d) comprises comparing an average value of the current applied to the main motor with the reference value while a rotation of the main motor is maintained at the target speed. ### Claim 13 (depends on 9) The control method according to claim 9, wherein step (d) comprises comparing a maximum value of the current applied to the main motor with the reference value while a rotation of the main motor is maintained at a target speed. ### Claim 14 (depends on 9) The control method according to claim 9, wherein the reference value is set within a prescribed range equal to or greater than an average current value when a current is applied to the main motor for maintaining a rotation of the main motor at the target speed in a state in which the inner tub is engaged with the main motor and equal to or less than an average current value when the current is applied to the main motor for maintaining the rotation of the main motor at the target speed in a state in which the inner tub is disengaged from the main motor. ### Claim 15 A control method of a washing machine comprising an inner tub, a pulsator rotatable in the inner tub, a main motor configured to rotate the pulsator, and a clutch configured to engage the inner tub with the main motor or disengage the inner tub from the main motor, the control method comprising: (a) executing a spin mode for driving the main motor in a state in which the inner tub is engaged with the main motor to rotate both the inner tub and the pulsator; (b) stopping the main motor; (c) operating the clutch for execution of an agitation mode for driving the main motor in a state in which the inner tub is disengaged from the main motor to rotate the pulsator; (d) accelerating the main motor until the main motor reaches a predetermined target speed and then stopping the main motor; (e) comparing a maximum value of current applied to the main motor during execution of step (d) with a predetermined reference value to determine whether the agitation mode can be executed; and (f) executing the agitation mode when a comparison result at step (e) indicates that the current value applied to the main motor is equal to or greater than the reference value, wherein step (b) is re-executed when the comparison result at step (e) indicates that the current value applied to the main motor is less than the reference value. ### Claim 16 (depends on 15) The control method according to claim 15, further comprising: sensing laundry weight; and setting the reference value based on the sensed laundry weight. ### Claim 17 (depends on 15) The control method according to claim 15, wherein step (d) comprises maintaining a rotation of the main motor at the target speed. ### Claim 18 A control method of a washing machine comprising an inner tub, a pulsator rotatable in the inner tub, a main motor configured to rotate the pulsator, and a clutch configured to engage the inner tub with the main motor or disengage the inner tub from the main motor, the control method comprising: (a) executing an agitation mode for driving the main motor in a state in which the inner tub is disengaged from the main motor to rotate the pulsator; (b) stopping the main motor; (c) operating the clutch for execution of a spin mode for driving the main motor in a state in which the inner tub is engaged with the main motor to rotate both the inner tub and the pulsator; (d) accelerating the main motor until the main motor reaches a predetermined target speed and then stopping the main motor; (e) comparing a maximum value of current applied to the main motor during execution of step (d) with a predetermined reference value to determine whether the agitation mode can be executed; and (f) executing the spin mode when a comparison result at step (e) indicates that the current value applied to the main motor is less than the reference value, wherein step (b) is re-executed when the comparison result at step (e) indicates that the current value applied to the main motor is equal to or greater than the reference value. ### Claim 19 (depends on 18) The control method according to claim 18, further comprising: sensing laundry weight; and setting the reference value based on the sensed laundry weight. ### Claim 20 (depends on 18) The control method according to claim 18, wherein step (d) comprises maintaining a rotation of the main motor at the target speed.