Laundry treating appliance and methods of operation

Abstract

A method of operating a laundry treating appliance includes accelerating rotation of the drum, determining a torque of the motor, an acceleration of the drum, a speed of the drum, and/or an angular position of the drum, repeatedly estimating the inertia of a laundry load using a parameter estimator based on the torque, acceleration, speed, and/or angular position of the drum, and monitoring a rate of change of the inertia from the repeated estimations of inertia. If the rate of change equals a threshold, the acceleration is adjusted.

1 . A method of operating a laundry treating appliance having a drum at least partially defining a treating chamber for receiving a laundry load for treatment according to a cycle of operation, and a motor operably coupled with the drum to rotate the drum the method comprising:
 accelerating rotation of the drum;   determining, during the accelerating rotation, by a controller communicably coupled with the motor, at least one of a torque of the motor, an acceleration of the drum, a speed of the drum, and an angular position of the drum;   repeatedly estimating with a parameter estimator, during the accelerating rotation, inertia of a laundry load, based on at least one of the torque, acceleration, speed, and angular position of the drum;   monitoring a rate of change of the inertia from the repeated estimations of inertia;   comparing the rate of change to a threshold; and   adjusting the acceleration when the rate of change equals the threshold.   
     
     
         2 . The method of  claim 1  further comprising rotating the drum at a dwell speed when the acceleration ceases for a dwell time. 
     
     
         3 . The method of  claim 2  wherein the dwell time is a function of the dwell speed. 
     
     
         4 . The method of  claim 2  wherein the dwell time is predetermined. 
     
     
         5 . The method of  claim 1  wherein repeatedly estimating the inertia utilizes a first model comprising:
     T=J{dot over (ω)}+bω+c+A  sin(α+β)
 
 
       wherein T=torque, J=inertia, {dot over (ω)}=acceleration of the drum, ω=rotational speed of the drum, b=viscous friction, c=coulomb friction, A=amplitude of the basket speed first harmonic torque disturbance, which may be a function of the unbalance mass, surface tilt angle, gravitational acceleration, unbalance mass position, and basket speed, α=rotational position of the drum, and β=rotational position of the imbalance of the laundry load relative to the rotational position of the drum. 
     
     
         6 . The method of  claim 5  wherein repeatedly estimating the inertia utilizes a second model comprising:
     T=J{dot over (ω)}+bω+c+A  sin(α+β)+ B   BB  sin(α BB +β BB )
 
 
       wherein T=torque, J=inertia, {dot over (ω)}=acceleration of the drum, ω=rotational speed of the drum, b=viscous friction, c=coulomb friction, A=amplitude of the basket speed first harmonic torque disturbance, which may be a function of the unbalance mass, surface tilt angle, gravitational acceleration, unbalance mass position, and basket speed, α=rotational position of the drum, β=rotational position of the imbalance of the laundry load relative to the rotational position of the drum, B BB =amplitude of a balancer disturbance, which may be a function of unbalance mass in the balancer, surface tilt angle, gravitational acceleration, unbalance mass position, and basket speed, α BB =rotational position reference for the balancer mass, and β BB =rotational position of the center of balancer mass of the mass relative to the rotational reference position α BB . 
     
     
         7 . The method of  claim 1  wherein the threshold is related to a desired remaining moisture content. 
     
     
         8 . The method of  claim 1  wherein the threshold is based on one of a gradient of the rate of change, an absolute value of inertia, an inertia ratio, or any combination thereof. 
     
     
         9 . The method of  claim 1  wherein the threshold is determined empirically. 
     
     
         10 . The method of  claim 1  wherein repeatedly estimating includes periodically estimating. 
     
     
         11 . The method of  claim 1  wherein adjusting includes one of ceasing or decreasing the acceleration. 
     
     
         12 . A laundry treating appliance comprising:
 a drum at least partially defining a treating chamber for receiving a laundry load for treatment according to a cycle of operation;   a motor operably coupled with the drum to accelerate rotation of the drum;   a controller coupled to the motor for determining at least one of a torque of the motor, an acceleration of the drum, a rotational speed of the drum, and an angular position of the drum; and   a processor operably coupled with the controller and having a parameter estimator to repeatedly estimate inertia of a laundry load based upon at least one of the torque, acceleration, speed, and angular position of the drum as the drum rotates;   wherein the processor is configured to monitor a rate of change of the inertia from the repeated estimations of inertia, to compare the rate of change to at least one threshold; and to signal the controller to adjust the acceleration when the rate of change equals or exceeds the threshold.   
     
     
         13 . The laundry treating appliance of  claim 9  wherein the processor is configured to signal the controller to rotate the drum at a dwell speed when the acceleration ceases for a dwell time. 
     
     
         14 . The laundry treating appliance of  claim 10  wherein the dwell time is a function of the dwell speed, load size, load type, wet to dry ratio, or any combination thereof. 
     
     
         15 . The laundry treating appliance of  claim 10  wherein the dwell time is predetermined. 
     
     
         16 . The laundry treating appliance of  claim 9  wherein the threshold is related to a desired remaining moisture content. 
     
     
         17 . The laundry treating appliance of  claim 9  wherein the threshold is based on one of a gradient of the rate of change, an absolute value of the inertia, or both. 
     
     
         18 . The laundry treating appliance of  claim 9  wherein the threshold is determined empirically.