Method for preventing spin out-of-balance conditions in a washing machine appliance

Abstract

A washing machine appliance includes a tub positioned within a cabinet, a basket rotatably mounted within the tub and defining a wash chamber for receipt of articles for washing, an agitation element positioned in the wash basket, a motor in mechanical communication with the wash basket and agitation element and being configured for selectively rotating the wash basket and agitation element, a measurement device mounted to the tub for detecting the displacement amount of the tub, and a controller operatively coupled to the motor and measurement device. The controller is configured to control an operation of the motor to rotate the agitation element for a first agitation stroke distance, determine the displacement amount of the tub relative to first and second tub displacement thresholds based on the displacement amount detected by the measurement device, and perform an out-of-balance agitation cycle based on the displacement amount relative to the displacement thresholds.

What is claimed is: 
     
         1 . A washing machine appliance, comprising:
 a tub positioned within a cabinet;   a basket rotatably mounted within the tub, the basket defining a wash chamber for receipt of articles for washing;   an agitation element positioned in the wash basket;   a motor in mechanical communication with the wash basket and the agitation element, the motor being configured for selectively rotating the wash basket and the agitation element within the tub;   a measurement device mounted to the tub for detecting a displacement amount of the tub; and   a controller operatively coupled to the motor and the measurement device, the controller configured to:
 control an operation of the motor to rotate the agitation element for a first agitation stroke distance; 
 determine the displacement amount of the tub, based on the displacement amount of the tub detected by the measurement device, relative to a first tub displacement threshold and a second tub displacement threshold; and 
 perform an out-of-balance agitation cycle based on the determined displacement amount relative to the first and second tub displacement thresholds. 
   
     
     
         2 . The washing machine appliance of  claim 1 , wherein the controller is configured to:
 perform a first out-of-balance agitation cycle when the determined displacement amount exceeds the first tub displacement threshold.   
     
     
         3 . The washing machine appliance of  claim 2 , further comprising:
 a water control valve for regulating a flow of water from a water supply source into the tub,   wherein, performing the first out-of-balance agitation cycle, comprises:
 controlling an operation of the water control valve to dispense a volume of water into the tub. 
   
     
     
         4 . The washing machine appliance of  claim 3 , wherein, after the volume of water is dispensed into the tub, the controller is configured to:
 control the operation of the motor to rotate the agitation element for the first agitation stroke distance;   determine the displacement amount of the tub based on the displacement amount of the tub detected by the measurement device; and   perform a second out-of-balance agitation cycle when the determined displacement amount falls between the first tub displacement threshold and the second tub displacement threshold.   
     
     
         5 . The washing machine appliance of  claim 1 , wherein the controller is configured to:
 perform a second out-of-balance agitation cycle when the determined displacement amount falls between the first tub displacement threshold and the second tub displacement threshold.   
     
     
         6 . The washing machine appliance of  claim 5 , wherein, performing the second out-of-balance agitation cycle comprises:
 controlling the operation of the motor to rotate the agitation element for a second agitation stroke distance greater than or equal to the first agitation stroke distance.   
     
     
         7 . The washing machine appliance of  claim 5 , wherein, the controller is configured to:
 repeat performing the second out-of-balance agitation cycle until the second out-of-balance agitation cycle has been performed for a predetermined number of times or the determined displacement amount falls below the second tub displacement threshold.   
     
     
         8 . The washing machine appliance of  claim 7 , wherein the controller is configured to:
 increase the second tub displacement threshold when the second out-of-balance agitation cycle has been performed for the predetermined number of times.   
     
     
         9 . The washing machine appliance of  claim 8 , wherein the controller is further configured to:
 control the operation of the motor to rotate the agitation element for the first agitation stroke distance;   determine the displacement amount of the tub based on the displacement amount of the tub detected by the measurement device; and   perform the second out-of-balance agitation cycle when the determined displacement amount falls between the first tub displacement threshold and the increased second tub displacement threshold.   
     
     
         10 . The washing machine appliance of  claim 1 , wherein the controller is configured to:
 initiate a spin cycle when the determined displacement amount falls below the second tub displacement threshold.   
     
     
         11 . The washing machine appliance of  claim 1 , wherein the first tub displacement threshold is greater than the second tub displacement threshold. 
     
     
         12 . The washing machine appliance of  claim 1 , wherein the measurement device comprises an accelerometer or a gyroscope. 
     
     
         13 . The washing machine appliance of  claim 1 , wherein the controller is configured to:
 calculate a trendline based on the determined displacement amount of the tub.   
     
     
         14 . The washing machine appliance of  claim 13 , wherein the trend line is calculated utilizing a linear regression technique. 
     
     
         15 . A method for operating a washing machine appliance, the washing machine appliance including a tub positioned within a cabinet, a basket rotatably mounted within the tub, the basket defining a wash chamber for receipt of articles for washing, an agitation element positioned in the wash basket, a motor in mechanical communication with the wash basket and the agitation element, the motor being configured for selectively rotating the wash basket and the agitation element within the tub, and a water control valve for regulating a flow of water from a water supply source into the tub, the method comprising:
 controlling an operation of the motor to rotate the agitation element for a first agitation stroke distance;   determining a displacement amount of the tub relative to a first tub displacement threshold and a second tub displacement threshold; and   performing an out-of-balance agitation cycle based on the determined displacement amount relative to the first and second tub displacement thresholds.   
     
     
         16 . The method of  claim 15 , further comprising:
 performing a first out-of-balance agitation cycle when the determined displacement amount exceeds the first tub displacement threshold.   
     
     
         17 . The method of  claim 16 , wherein performing the first out-of-balance agitation cycle comprises:
 controlling an operation of the water control valve to dispense a volume of water into the tub.   
     
     
         18 . The method of  claim 15 , further comprising:
 performing a second out-of-balance agitation cycle when the determined displacement amount falls between the first tub displacement threshold and the second tub displacement threshold.   
     
     
         19 . The method of  claim 18 , wherein performing the second out-of-balance agitation cycle comprises:
 controlling the operation of the motor to rotate the agitation element for a second agitation stroke distance greater than or equal to the first agitation stroke distance.   
     
     
         20 . The method of  claim 18 , further comprising:
 repeating performing the second out-of-balance agitation cycle until the second out-of-balance agitation cycle has been performed for a predetermined number of times or the determined displacement amount falls below the second tub displacement threshold.