Method of operating a laundry treating appliance to detect contact between a drum and tub

Abstract

A method of operating a laundry treating appliance with a rotating drum located within a tub to detect contact between the drum and a tub.

1 . A method of operating a laundry treating appliance having a rotating drum, driven by a motor, with the drum located within a tub, the method comprising:
 rotating the drum by driving the motor;   monitoring the mechanical drag acting on the drum and the corresponding rotational speed of the drum while the drum is being rotated;   comparing the mechanical drag to a reference mechanical drag for the corresponding rotational speed; and   determining the presence of a contact between the drum and the tub when the mechanical drag exceeds a predetermined drag threshold for the corresponding rotational speed.   
     
     
         2 . The method of  claim 1  wherein driving the motor comprises providing the motor with an acceleration rate. 
     
     
         3 . The method of  claim 1  wherein the monitoring is non-continuous. 
     
     
         4 . The method of  claim 3  wherein the monitoring is done at a predetermined sampling rate. 
     
     
         5 . The method of  claim 1  wherein the comparison is done when the rotational speed exceeds a reference speed. 
     
     
         6 . The method of  claim 5  wherein the reference speed is greater than a satellizing speed. 
     
     
         7 . The method of  claim 6  wherein the reference speed is greater than 500 rpm. 
     
     
         8 . The method of  claim 1  wherein the presence of a contact between the drum and the tub is determined when the mechanical drag exceeds the predetermined drag threshold by a predetermined amount. 
     
     
         9 . The method of  claim 1  wherein the mechanical drag is determined by monitoring a relationship between power consumed by the motor, an inertia, and an acceleration of the drum. 
     
     
         10 . A method of operating a laundry treating appliance having a rotating drum, driven by a motor, with the drum located within a tub, the method comprising:
 accelerating rotational speed of the drum by driving the motor;   monitoring at least one of drum acceleration, drum speed and power consumed by the motor;   defining a real-time relationship between the power consumed and at least one of the acceleration and speed;   comparing the real-time relationship to a threshold relationship; and   determining the presence of a contact between the drum and the tub when the real-time relationship satisfies the threshold relationship.   
     
     
         11 . The method of  claim 10  wherein driving the motor comprises providing the motor with an acceleration rate. 
     
     
         12 . The method of  claim 10  wherein the monitoring is non-continuous. 
     
     
         13 . The method of  claim 12  wherein the monitoring is done at a predetermined sampling rate. 
     
     
         14 . The method of  claim 10  wherein the comparison is done when the rotational speed exceeds a reference speed. 
     
     
         15 . The method of  claim 14  wherein the reference speed is greater than a satellizing speed. 
     
     
         16 . The method of  claim 15  wherein the reference speed is greater than 500 rpm. 
     
     
         17 . The method of  claim 10  wherein the real-time relationship satisfies the threshold relationship when the real-time power consumed is greater than a reference power for reference relationship. 
     
     
         18 . The method of  claim 17  wherein the real-time relationship satisfies the threshold relationship when the real-time power consumed is greater than the reference power by a predetermined amount.