Improvements relating to laundry apparatus and/or their control

Abstract

A method of mitigating an out of balance washing load in a washing machine with a horizontal axis drum comprising: determining an indication of an angular position, and optionally a radial position, of a OOB mass of the washing machine drum, and controlling rotational speed of the drum so that, as the drum and OOB mass rotates, a rotational speed of the drum is varied relative to a usual speed based on the OOB mass so that an outward radial force on the washing load reduces below the inwards radial force and/or of gravity.

1 . A method of mitigating an out of balance laundry load in a laundry machine with a horizontal axis drum, comprising the steps of:
 spinning the drum above a satellisation speed of the laundry load; and   within a single revolution of the drum, varying the drum speed by sequentially decreasing and then increasing the drum speed below and then above satellisation speed, to selectively allow at least some of the laundry load to drop under gravity.   
     
     
         2 . The method of  claim 1  wherein the rate at which drum speed is decreased to a speed below satellisation speed is more rapid than the rate at which drum speed is subsequently increased to a speed above satellisation speed. 
     
     
         3 . The method of  claim 1  further comprising the step of:
 determining a position (which is optionally an angular position) of an out of balance mass of the out of balance laundry load. 
 
     
     
         4 . The method of  claim 3  wherein the step of varying the drum speed coincides rotation of the drum below satellisation speed with the position of the out of balance mass being at, near, or passing through, a high point in its rotation about the horizontal axis of the drum. 
     
     
         5 . The method of  claim 3  further comprising the step of:
 determining a target zone with an angular extent relative to the angular position of the out of balance mass, and optionally with a radial extent relative to the radius of the drum; and 
 wherein, within a single revolution of the drum, drum speed is varied by sequentially decreasing and then increasing the drum speed below and then above satellisation speed, to selectively cause laundry load located within the target zone to drop under gravity. 
 
     
     
         6 . The method of  claim 5  wherein the angular extent of the target zone is between about 0-90 degrees in either direction relative to the position of the out of balance mass; or optionally between about 0-45 degrees, about 0-30 degrees, about 0-15 degrees, or about 0-5 degrees in either direction relative to the position of the out of balance mass. 
     
     
         7 . The method of  claim 5  wherein the radial extent of the target zone is between about 25-100 percent of the radius of the drum; or optionally between about 40-100 percent, about 60-100 percent, about 80-100 percent, or about 90-100 percent of the radius of the drum. 
     
     
         8 . The method  claim 3  wherein one or more selected from the following are used as inputs from which to determine the position of the out of balance mass.
 a. motor torque, power, current, speed, or voltage; and/or 
 b. a time (relative to a reference time point); and/or 
 c. drum speed, drum angular position, drum linear acceleration and/or drum angular acceleration. 
 
     
     
         9 . The method of  claim 3  wherein the position of the out of balance mass is determined using:
 a. sensor data, optionally selected from one or more of data from an accelerometer or gyroscope; and/or 
 b. motor data, optionally selected from one or more of motor torque, power, current, speed or voltage. 
 
     
     
         10 . The method of  claim 9  wherein the position of the out of balance mass is determined using only motor data. 
     
     
         11 . The method of  claim 1  wherein, during the step of varying the drum speed by sequentially decreasing and then increasing the drum speed below and then above satellisation speed, the rotational speed of the drum is controlled using a control signal with a profile that varies from a previous normal and/or constant control signal profile, and optionally has a pulsed profile. 
     
     
         12 . The method of  claim 11  wherein the control signal varies based on one or more selected from:
 a. motor torque, power, current, speed, or voltage; and/or 
 b. a time (relative to a reference time point); and/or 
 c. drum speed, drum angular position, drum linear acceleration and/or drum angular acceleration; and/or 
 d. the mass of the laundry load; and/or 
 e. the size/diameter of the drum; 
 
     
     
         13 . The method of  claim 11  wherein the control signal comprises one or more selected from:
 a. an angular start position/angular span/angular stop position of rotational speed decrease and subsequent speed increase; 
 b. a time (relative to a reference time point) at which rotational speed decrease and subsequent speed increase is initiated and/or concluded; 
 c. a slope or rate of rotational speed decrease and subsequent speed increase; and/or 
 d. a magnitude or amplitude of rotational speed decrease and subsequent speed increase. 
 
     
     
         14 . The method of  claim 11  wherein the control signal profile creates a rotational speed profile of the rotating drum that selectively causes laundry load in the drum to drop under gravity;
 and optionally wherein the control signal profile creates a rotational speed profile of the rotating drum that selectively causes laundry load in the target zone to drop under gravity. 
 
     
     
         15 . (canceled) 
     
     
         16 . (canceled) 
     
     
         17 . (canceled) 
     
     
         18 . A method of mitigating an out of balance washing load in a washing machine with a horizontal axis drum comprising:
 determining an indication of an OOB mass of the washing machine drum, and   controlling rotational speed of the drum so that, as the drum and OOB mass rotates, a rotational speed of the drum is varied, within one revolution of the drum, relative to a usual speed based on the OOB mass so that an outward radial force on the washing load reduces below the inwards radial force and/or of gravity.   
     
     
         19 . (canceled) 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . A method according to  claim 18  wherein the rotational speed of the drum is controlled using a control signal with a profile that varies from a normal control signal. 
     
     
         24 . (canceled) 
     
     
         25 . (canceled) 
     
     
         26 . A method according to  claim 23  wherein the control signal profile creates a rotational speed profile of the rotating drum that creates a target region which redistributes an OOB mass and/or washing load in the target region. 
     
     
         27 . A method according to  claim 26  wherein the target region comprises and angular span and a radial extent. 
     
     
         28 . A laundry apparatus comprising:
 a drum,   a motor to rotate the drum,   one or more sensors, and   a controller that receives input from the sensors and controls the motor to rotate the drum,   wherein the controller is configured to mitigate an out of balance washing load according to  claim 18 .   
     
     
         29 . The method of  claim 1  wherein the drum is spun at a constant speed above satellisation speed prior to, and optionally following, the step of varying drum speed within a single revolution of the drum.