Dishwasher and method for controlling the dishwasher

Abstract

A dishwasher according to an embodiment of the disclosure relates to providing a control method for determining whether a filter is clogged. A dishwasher according to an embodiment of the disclosure may comprise a tub, a sump assembly disposed under the tub and storing washing water, a circulation pump pumping and circulating the washing water stored in the sump assembly, at least one jet device jetting the washing water pumped by the circulation pump into the tub, a filter disposed under the tub and filtering a foreign object flowing inside the tub, a current sensor detecting a driving current input to the circulation pump, a vibration sensor detecting a vibration signal of the tub generated by driving of the circulation pump, and a controller configured to detect whether the filter is clogged based on information obtained from the current sensor and the vibration sensor.

What is claimed is: 
     
         1 . A dishwasher comprising:
 a tub;   a sump assembly configured to store washing water;   a circulation pump that is drivable via a driving current to pump the washing water stored in the sump assembly;   at least one jet device configured to jet the washing water pumped by the circulation pump into the tub;   a filter configured to filter a foreign object from the washing water;   a current sensor configured to sense the driving current and to produce a corresponding sensed value;   a vibration sensor configured to sense vibration of the tub and to produce a corresponding sensed value; and   a controller configured to:
 obtain a first natural frequency of the tub based on the sensed value produced by the vibration sensor, 
 obtain a second natural frequency of the tub based on the sensed value produced by the vibration sensor, in response to the sensed value produced by the current sensor indicating that the driving current is less than a reference current, and 
 determine that the filter is in a clogged state based on a variation in the second natural frequency with respect to the first natural frequency exceeding a preset threshold range. 
   
     
     
         2 . The dishwasher of  claim 1 , wherein the sump assembly is under the tub, and the vibration sensor is under the sump assembly. 
     
     
         3 . The dishwasher of  claim 2 , wherein the vibration sensor is adjacent to the circulation pump. 
     
     
         4 . The dishwasher of  claim 1 , wherein the vibration sensed by the vibration sensor corresponds to an amount of the washing water collected in the tub. 
     
     
         5 . The dishwasher of  claim 1 , wherein the vibration sensor includes an accelerometer or a strain gauge. 
     
     
         6 . The dishwasher of  claim 1 , wherein
 the first natural frequency is a natural frequency of the tub obtained in response to initiation of a water supply process included in a washing cycle, and   the second natural frequency is a natural frequency of the tub after completion of water supply process.   
     
     
         7 . The dishwasher of  claim 1 , further comprising:
 an actuator on a surface of the tub and configured to vibrate the tub,   wherein the controller is configured to obtain the first natural frequency and the second natural frequency from the vibration sensor in response to the vibration of the tub by the actuator.   
     
     
         8 . The dishwasher of  claim 1 , wherein the controller is configured to, when a difference between the first natural frequency and the second natural frequency is within the preset threshold range, determine that a water level of the washing water stored in the tub is lower than a reference water level. 
     
     
         9 . The dishwasher of  claim 8 , wherein the controller is configured to, when a number of times in which the washing water is supplied to the tub is less than a threshold number, control the circulation pump to supply a predetermined volume of the washing water to the tub. 
     
     
         10 . The dishwasher of  claim 8 , wherein the reference water level is set to a water level at which the washing water collected in the tub reaches an uppermost end of the sump assembly. 
     
     
         11 . The dishwasher of  claim 1 , further comprising:
 a display,   wherein the controller is configured to, when the filter is determined to be in the clogged state, display information indicating the clogged state of the filter on the display.   
     
     
         12 . The dishwasher of  claim 1 , further comprising:
 a communication unit configured to wirelessly communicate with an external device,   wherein the controller is configured to, when the filter is determined to be in the clogged state, transfer guide information instructing management of the filter to the external device through the communication unit.   
     
     
         13 . A method for controlling a dishwasher that includes a tub, a sump assembly configured to store washing water, a circulation pump that is drivable via a driving current to pump the washing water stored in the sump assembly, at least one jet device configured to jet the washing water pumped by the circulation pump into the tub, a filter configured to filter a foreign object from the washing water, a current sensor configured to sense the driving current and to produce a corresponding sensed value, and a vibration sensor configured to sense vibration of the tub and to produce a corresponding sensed value, the method comprising:
 obtaining a first natural frequency of the tub based on the sensed value produced by the vibration sensor;   obtaining a second natural frequency of the tub based on the sensed value produced by the vibration sensor, in response to the sensed value produced by the current sensor indicating that the driving current is less than a reference current; and   determining that the filter is in a clogged state based on a variation in the second natural frequency with respect to the first natural frequency exceeding a preset threshold range.   
     
     
         14 . The method of  claim 13 , wherein the vibration sensed by the vibration sensor corresponds to an amount of the washing water collected in the tub. 
     
     
         15 . The method of  claim 13 , wherein
 the first natural frequency is a natural frequency of the tub obtained in response to initiation of a water supply process included in a washing cycle, and   the second natural frequency is a natural frequency of the tub after completion of the water supply process.   
     
     
         16 . The method of  claim 13 , further comprising:
 when a difference between the first natural frequency and the second natural frequency is within the preset threshold range, determining that a water level of the washing water stored in the tub is lower than a reference water level.   
     
     
         17 . The method of  claim 16 , further comprising:
 when a number of times in which the washing water is supplied to the tub is less than a threshold number, controlling the circulation pump to supply a predetermined volume of the washing water to the tub.   
     
     
         18 . The method of  claim 16 , wherein the reference water level is set to a water level at which the washing water collected in the tub reaches an uppermost end of the sump assembly. 
     
     
         19 . The method of  claim 13 , further comprising:
 when the filter is determined to be in the clogged state, displaying information indicating the clogging state of the filter on a display.   
     
     
         20 . The method of  claim 13 , further comprising:
 when the filter is determined to be in the clogged state, transferring guide information instructing management of the filter to an external device.