Method for detecting dewatering load in washing machine and washing machine control method using the same

Abstract

A method for detecting a dewatering load in a washing machine and a washing machine control method using the same are provided. The dewatering load is detected, and the washing machine is controlled accordingly, by first determining an acceleration or deceleration time and applying the principle that the laundry load during dewatering corresponds to the time required for accelerating/decelerating a washing tub driven by a motor, to drive the washing tub at a predetermined rotational speed based on the detection or to stop its rotation based on a determination of an overload condition. The control method includes steps of initiating a dewatering step, by driving the washing tub from a first predetermined rotational speed to a second predetermined rotational speed; detecting a load amount present in the driven washing tub, using the principle that the load amount corresponds to a time required for the driving of the washing tub from the first predetermined rotational speed to the second predetermined rotational speed; determining a time lapse between the driving of the washing tub at the first predetermined rotational speed and the driving of the washing tub at the second predetermined rotational speed; comparing the determined time lapse with a reference value in a lookup table; and performing dewatering based on the detected load amount, wherein the dewatering is performed at a predetermined maximum dewatering speed corresponding to the detected load amount and wherein the dewatering is interrupted if the detected load amount exceeds a predetermined reference value. The second predetermined rotational speed may be a steady rotational speed, whereby the driving of the washing tub is performed by accelerating the washing tub by applying a constant motor torque. Alternatively, the first predetermined rotational speed may be the steady rotational speed, whereby the driving of the washing tub is performed by decelerating the washing tub by way of freewheeling the motor, applying dynamic braking, or applying anti-phase braking.

What is claimed is:  
     
         1 . A method for detecting a dewatering load in a washing machine having a washing tub driven by a motor, the method comprising steps of: 
 driving the washing tub from a first predetermined rotational speed to a second predetermined rotational speed;    determining a time lapse between the driving of the washing tub at the first predetermined rotational speed and the driving of the washing tub at the second predetermined rotational speed; and    comparing the determined time lapse with a set of reference values in a lookup table.    
     
     
         2 . The method as claimed in  claim 1 , wherein the second predetermined rotational speed is a steady rotational speed and the driving of the washing tub is performed by accelerating the washing tub by applying a constant motor torque.  
     
     
         3 . The method as claimed in  claim 1 , wherein the first predetermined rotational speed is a steady rotational speed and the driving of the washing tub is performed by decelerating the washing tub by means of one of freewheeling the motor, applying dynamic braking, and applying anti-phase braking.  
     
     
         4 . A method for controlling a washing machine having a washing tub driven by a motor, the method comprising steps of: 
 initiating a dewatering step, by driving the washing tub from a first predetermined rotational speed to a second predetermined rotational speed;    detecting a load amount present in the driven washing tub, using the principle that the load amount corresponds to a time required for the driving of the washing tub from the first predetermined rotational speed to the second predetermined rotational speed; and    performing dewatering based on the detected load amount.    
     
     
         5 . The method as claimed in  claim 4 , wherein the second predetermined rotational speed is a steady rotational speed and the driving of the washing tub is performed by accelerating the washing tub by applying a constant motor torque.  
     
     
         6 . The method as claimed in  claim 5 , the method further comprising steps of: 
 determining a time lapse between the driving of the washing tub at the first predetermined rotational speed and the driving of the washing tub at the second predetermined rotational speed; and    comparing the determined time lapse with a set of reference values in a lookup table,    wherein the dewatering is performed at a predetermined maximum dewatering speed corresponding to the detected load amount and wherein the dewatering is interrupted if the detected load amount exceeds a predetermined reference value.    
     
     
         7 . The method as claimed in  claim 4 , wherein the first predetermined rotational speed is a steady rotational speed and the driving of the washing tub is performed by decelerating the washing tub by means of one of freewheeling the motor, applying dynamic braking, and applying anti-phase braking.  
     
     
         8 . The method as claimed in  claim 7 , the method further comprising steps of: 
 determining a time lapse between the driving of the washing tub at the first predetermined rotational speed and the driving of the washing tub at the second predetermined rotational speed; and    comparing the determined time lapse with a reference value in a lookup table,    wherein the dewatering is performed at a predetermined maximum dewatering speed corresponding to the detected load amount and wherein the dewatering is interrupted if the detected load amount exceeds a predetermined reference value.