Methods for determining load mass in washing machine appliances

Patent metadata

Field	Value
Publication number	US-2016369446-A1
Application number	US-201514741630-A
Country	US
Kind code	A1
Filing date	Jun 17, 2015
Priority date	Jun 17, 2015
Publication date	Dec 22, 2016
Grant date	—

Abstract

Washing machine appliances and methods for determining load masses are provided. A method includes accelerating rotation of a basket of the washing machine appliance from a first speed to a second speed greater than the first speed and for a predetermined time measured for acceleration of the basket from the first speed; measuring, during the accelerating step, a check speed of the basket at the predetermined time; and measuring, during the accelerating step, an acceleration time for the tub to accelerate from the first speed to the second speed. The method further includes discontinuing acceleration of the basket after the second speed and the predetermined time have reached; and measuring a coast time for coasting of the basket from the check speed to the first speed. The method further includes determining a load mass in the basket based on the check speed, the acceleration time, and the coast time.

First claim

What is claimed is:

1 . A method for determining a load mass in a washing machine appliance, the method comprising:
accelerating rotation of a basket about a central axis within a tub of the washing machine appliance from a first speed to a second speed greater than the first speed and for a predetermined time measured for acceleration of the basket from the first speed; measuring, during the accelerating step, a check speed of the basket at the predetermined time; measuring, during the accelerating step, an acceleration time for the tub to accelerate from the first speed to the second speed; discontinuing acceleration of the basket after the second speed and the predetermined time have been reached; measuring a coast time for coasting of the basket from the check speed to the first speed; and determining a load mass in the basket based on the check speed, the acceleration time, and the coast time.

2 . The method of claim 1 , wherein the coast time is a second coast time, and further comprising the step of measuring a first coast time for coasting of the basket from the second speed to the first speed.

3 . The method of claim 1 , further comprising measuring a current to the washing machine appliance during the accelerating step.

4 . The method of claim 1 , further comprising measuring a voltage to the washing machine appliance during the accelerating step.

5 . The method of claim 4 , further comprising measuring a voltage to the washing machine appliance after the discontinuing step.

6 . The method of claim 5 , further comprising subtracting the voltage after the discontinuing step from the voltage during the accelerating step to determine a voltage sag.

7 . The method of claim 1 , wherein the determining step comprises utilizing a transfer function to determine the load mass, and wherein the check speed, the acceleration time, and the coast time are inputs to the transfer function.

8 . The method of claim 1 , further comprising continuing accelerating rotation of the basket to an overshoot speed after the second speed and predetermined time have been reached.

9 . The method of claim 1 , wherein the first speed is between approximately 10 and approximately 30 revolutions per minute.

10 . The method of claim 1 , wherein the second speed is between approximately 120 and approximately 180 revolutions per minute.

11 . The method of claim 1 , wherein the predetermined time is between approximately 1 and approximately 5 seconds.

12 . The method of claim 1 , comprising performing a load sense spin, wherein the step of performing the load sense spin comprises performing the accelerating step, the step of measuring the check speed, the step of measuring the acceleration time, the discontinuing step, the step of measuring the coast time, and the determining step.

13 . The method of claim 12 , further comprising:
repeating the step of performing the load sense spin; and averaging the load mass from each performance of the load sense spin to determine an average load mass.

14 . A washing machine appliance, the washing machine appliance comprising:
a cabinet; a tub disposed within the cabinet; a basket disposed within the tub and rotatable relative to the tub about a central axis; a motor connected to the basket and operable to rotate the basket; and a controller in communication with the motor, the controller configured for:
accelerating rotation of the basket about the central axis from a first speed to a second speed greater than the first speed and for a predetermined time measured for acceleration of the basket from the first speed;
measuring, during the accelerating step, a check speed of the basket at the predetermined time;
measuring, during the accelerating step, an acceleration time for the tub to accelerate from the first speed to the second speed;
discontinuing acceleration of the basket after the second speed and the predetermined time have been reached;
measuring a coast time for coasting of the basket from the check speed to the first speed; and
determining a load mass in the basket based on the check speed, the acceleration time, and the coast time.

15 . The washing machine appliance of claim 14 , wherein the coast time is a second coast time, and wherein the controller is further configured for comprising the step of measuring a first coast time for coasting of the basket from the second speed to the first speed.

16 . The washing machine appliance of claim 14 , wherein the controller is further configured for measuring a current to the washing machine appliance during the accelerating step.

17 . The washing machine appliance of claim 14 , wherein the controller is further configured for:
measuring a voltage to the washing machine appliance during the accelerating step; measuring a voltage to the washing machine appliance after the discontinuing step; and subtracting the voltage after the discontinuing step from the voltage during the accelerating step to determine a voltage sag.

18 . The washing machine appliance of claim 14 , wherein the determining step comprises utilizing a transfer function to determine the load mass, and wherein the check speed, the acceleration time, and the coast time are inputs to the transfer function.

19 . The washing machine appliance of claim 14 , wherein the controller is further configured for continuing accelerating rotation of the basket to an overshoot speed after the second speed and predetermined time have been reached.

Assignees

• Gen Electric

Inventors

• Leonard Ryan Ellis
• Hettinger Stephen Edward

Classifications

• D06F34/18 Primary

  Condition of the laundry, e.g. nature or weight · CPC title

• D06F23/04

  and rotating or oscillating about a vertical axis · CPC title

• D06F2202/12

  Textiles & Paper · mapped topic

• G01P15/00

  Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration · CPC title

• D06F39/003 Primary

  Textiles & Paper · mapped topic