Method of determining volume of water to add to first and second washing compartments of a washing machine as a function of determined moment of inertia

A washing machine includes a first washing compartment to hold a first set of articles to be washed and a second washing compartment to holds a second set of articles to be washed, the second washing compartment having an inserted position and a removed position. A liquid flow valve is configured to connect to an external liquid source to selectively control flow of liquid from the external liquid source and into one or more of the first washing compartment and the second washing compartment. An electric motor is configured to rotate the first washing compartment, and the second washing compartment, when the second washing compartment is in the inserted position. A controller, in communication with the electric motor, determines a mass of the second set of articles and then determines, as a function of the determined mass, a volume of water to be added to the second washing compartment.

BACKGROUND OF THE DISCLOSURE

Clothes washing machines wash clothing, fabric, and other items (hereinafter collectively referred to as “articles”). Some washing machines utilize a tub with a solitary washing compartment, which can be perforated, disposed inside the tub. The solitary washing compartment holds the articles to be washed, and the tub holds a liquid such as water to assist in the washing operation. Some washing machines incorporate a first washing compartment, like the solitary washing compartment, as well as a second, removable, washing compartment. The second washing compartment allows for washing of a second set of articles simultaneously with the washing of a first set of articles in the first washing compartment.

However, there is a problem in that the washing machines that utilize the second, removable, washing compartment do not automatically determine an optimal amount of water to utilize in the second washing compartment. This failure can result in the additional problem of the washing machine adding a volume of liquid to the second washing compartment that overflows, along with any laundering chemicals in the second washing compartment, from the second washing compartment into the first washing compartment. That overflowing potentially transfers undesirable substances, such as bleach, dye, and cleaning agents, from the first washing compartment to the second washing compartment.

SUMMARY OF THE DISCLOSURE

The present disclosure solves those problems with a washing machine that estimates or calculates the mass of the set of articles in the second, removable, washing compartment, then determines a volume of water (insufficient to overflow into the first washing compartment) to add to the second washing compartment as a function of the estimated or calculated mass, and then adds that determined volume of water to the second washing compartment.

According to one aspect of the present disclosure, a washing machine includes a tub. A first washing compartment is disposed within the tub to hold a first set of articles to be washed, the first set of articles having a mass. A second washing compartment holds a second set of articles to be washed, the second set of articles having a mass, the second washing compartment having an inserted position and a removed position. A liquid flow valve is configured to connect to an external liquid source to selectively control flow of liquid from the external liquid source and into either the first washing compartment, the second washing compartment, or both the first washing compartment and the second washing compartment. An electric motor is operably coupled to and configured to cause the first washing compartment to rotate, and operably coupled to and configured to cause the second washing compartment to rotate when the second washing compartment is in the inserted position but not in the removed position. A controller is in communication with the electric motor that estimates or calculates the mass of the second set of articles held by the second washing compartment and then calculates, as a function of the estimated or calculated mass of the second set of articles, a volume of water to be added to the second washing compartment.

According to another aspect of the present disclosure, a washing machine includes a tub. A first washing compartment is disposed within the tub to hold a first set of articles to be washed, the first set of articles having a mass. A second washing compartment holds a second set of articles to be washed, the second set of articles having a mass, the second washing compartment having an inserted position and a removed position. A liquid flow valve is configured to connect to an external liquid source to selectively control flow of liquid from the external liquid source and into either the first washing compartment, the second washing compartment, or both the first washing compartment and the second washing compartment. An electric motor is operably coupled to and configured to cause the first washing compartment to rotate, and operably coupled to and configured to cause both the first washing compartment and the second washing compartment to rotate when the second washing compartment is in the inserted position but not in the removed position. A controller is in communication with the electric motor and is configured to: (a) to cause the electric motor to rotate together the first washing compartment and the second washing compartment at a predetermined rotational speed when the second washing compartment is in the inserted position and contains the second set of articles; (b) to cause liquid to flow from the external liquid source and into the second washing compartment while the second washing compartment is rotating at the predetermined rotational speed; (c) to cause the electric motor to maintain rotating the first washing compartment and the second washing compartment at the predetermined rotational speed, while monitoring the moment of inertia of the second washing compartment together with the second set of articles and the liquid in the second washing compartment; and (d) as the moment of inertia meets or exceeds a predetermined value, or as the moment of inertia meets or exceeds a predetermined rate of change, to cause the electric motor to stop rotating the first washing compartment and the second washing compartment and to stop liquid from flowing from a liquid supply system into the second washing compartment.

According to yet another aspect of the present disclosure, a method of adding a volume of water to a removable washing compartment of a washing machine includes, after a first set of articles is loaded into a first washing compartment of a washing machine and while a second washing compartment of the washing machine is in a removed position, estimating or calculating a mass of the first set of articles in the first washing compartment; after the second washing compartment is placed into an inserted position and a second set of articles is loaded into the second washing compartment, estimating or calculating a mass of the second set of articles in the second washing compartment; adding a second volume of water to the second washing compartment, without causing water added to the second washing compartment to overflow from the second washing compartment into the first washing compartment, the second volume of water determined as a function of the estimated or calculated mass of the second set of articles; and adding a first volume of water to the first washing compartment, the first volume of water determined as a function of the estimated or calculated mass of the first set of articles.

DETAILED DESCRIPTION

For purposes of description herein, the terms “rear,” “front,” “side,” “top,” “beneath,” and derivatives thereof shall relate to the disclosure as oriented inFIG. 1. However, it is to be understood that the disclosure may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

Referring toFIGS. 1-6, a washing machine10of the present disclosure is illustrated. The washing machine10illustrated is of the top loading variety, but could be of the front loading variety as well. The washing machine10includes a cabinet12. The cabinet12includes a front wall portion14, a rear wall portion16, and side wall portions18,20that extend from the front wall portion14to the rear wall portion16. The cabinet12further includes a top portion22with an opening24and a lid26disposed at the top portion22that can move to, from, and between an opened position28and a closed position30to selectively allow or deny access to the opening24. The front wall portion14, the rear wall portion16, and the side wall portions18,20can each be formed as separate pieces, or may be formed as one or more continuous pieces. For example, the rear wall portion16can be separate, while the front wall portion14and the side wall portions18,20can be continuous with each other. The front wall portion14, the rear wall portion16, and the side wall portions18,20can be mounted to a frame (not shown). The cabinet12defines an interior32enclosing components typically found in a conventional washing machine10, such as motors, pumps, fluid lines, controls, sensors, transducers, and the like. A user interface34can include multiple controls36(such as knobs and switches) and displays, and for communicating with the user, such as to receive input and provide output.

The washing machine10further includes a tub38and a first washing compartment40disposed within the tub38. In the illustrated embodiment, the first washing compartment40is perforated with perforations42while the tub38is not. The first washing compartment40can hold a first set of articles44to be washed. The first set of articles44has a mass, which will vary from load-to-load as a function of the composition of the first set of articles44.

A first agitator46is located in the first washing compartment40. During operation of the washing machine10, the first agitator46imparts mechanical agitation to the first set of articles44placed in the first washing compartment40and extends upwardly from the bottom of the first washing compartment40. The first washing compartment40and the first agitator46are driven by an electric motor48via a shaft50. Stated another way, the electric motor48is operably coupled to and configured to cause the first washing compartment40and the first agitator46to move. More specifically, the electric motor48includes the shaft50, and the shaft50rotates about an axis52. The electric motor48can cause the first agitator46to move independently of the first washing compartment40, such that the first agitator46can mechanically agitate as mentioned above while the first washing compartment40remains stationary. In addition, the electric motor48can cause the first washing compartment40and the first agitator46to rotate simultaneously about the axis52as the electric motor48causes the shaft50to rotate about the axis52, such as during a spin cycle as known in the art. The electric motor48can be a three-phase induction motor, a brushless permanent magnet (BPM), or a single-phase induction motor (i.e., a permanent split capacitor with motor sensing capabilities).

The washing machine10further includes a second washing compartment54. The second washing compartment54can hold a second set of articles56to be washed. The second set of articles56has a mass, which again varies from load-to-load depending on the composition of the second set of articles56. The second washing compartment54releasably couples to the first washing compartment40, such that when the electric motor48drives the first washing compartment40, the electric motor48drives the second washing compartment54as well. A second agitator55releasably couples to the first agitator46, such that when the electric motor48drives the first agitator46, the electric motor48drives the second agitator55as well. The second washing compartment54is removable in that the second washing compartment54is movable to, from, and between an inserted position58where the second washing compartment54is coupled to the first washing compartment40and a removed position59where the second washing compartment54is not coupled to the first washing compartment40and not beneath the lid26when the lid26is in the closed position30. The first washing compartment40can be utilized to wash the first set of articles44independently while the second washing compartment54is in the removed position59. When the second washing compartment54is in the inserted position58, the electric motor48can actuate the second washing compartment54through the first washing compartment40and cause the second washing compartment54to rotate about the axis52. Thus, when the second washing compartment54is in the inserted position58, as the electric motor48causes the shaft50to rotate about the axis52, both the first washing compartment40and the second washing compartment54can also rotate simultaneously about the axis52. When the second washing compartment54is in the inserted position58, the electric motor48can actuate the second agitator55through the first agitator46and cause the second agitator55to rotate about the axis52. Thus, when the second washing compartment54is in the inserted position58, as the electric motor48causes the shaft50to rotate about the axis52, both the first agitator46and the second agitator55can rotate simultaneously about the axis52. However, when the second washing compartment54is in the removed position59, the electric motor48cannot cause either the second washing compartment54or the second agitator55to rotate.

The washing machine10further includes a liquid flow valve60. The liquid flow valve60controls the inlet of liquid (such as water) into the washing machine10from an external liquid source62. The liquid flow valve60can be connected to the external liquid source62through tubing as known in the art. The liquid flow valve60selectively controls the flow of liquid from the external liquid source62into either the first washing compartment40, the second washing compartment54, or both the first washing compartment40and the second washing compartment54. For example, when the second washing compartment54is in the removed position59and only the first washing compartment40is being utilized to wash the first set of articles44, then the liquid flow valve60can control the flow of liquid from the external liquid source62to flow into the first washing compartment40. When the second washing compartment54is in the inserted position58to wash the second set of articles56, in addition to the first set of articles44in the first washing compartment40, the liquid flow valve60can cause liquid to flow from the external liquid source62into only the second washing compartment54at a certain point in time, only into the first washing compartment40at a different point in time, or into both the first washing compartment40and the second washing compartment54simultaneously.

The washing machine10further includes a controller64. The controller64can include a microprocessor66and a memory68. The microprocessor66can execute programs stored in the memory68to effectuate the method herein described below. The memory68can also be used to store information, such as a database, table, or calculated data pertinent to the method below, and to store data received from one or more components of the washing machine10that may be communicably coupled with the controller64. The controller64is in communication with, and controls the operation of, the electric motor48, the liquid flow valve60, and the washing machine10generally. The controller64can receive input from, and provide output to, the user of the washing machine10via the user interface34. The controller64performs further functions as described below. The controller64may also be coupled with one or more sensors70provided in one or more of the systems of the washing machine10to receive input from the sensors70, an example of which includes a torque measurement from the motor controller or a motor torque sensor70a.

The motor torque sensor70acan be a measurement device that is part of the electric motor48separate from the controller64or can be part of the controller64, separate from the electric motor48, that collects measurements from the electric motor48and computes torque. Contemporary electric motors48often incorporate a dedicated controller that can output data relative to the electric motor48to the controller64, such as rotational speed, current utilized, voltage applied, direction of rotation, and torque imparted, etc. If the dedicated controller does not specifically output data concerning torque imparted, but outputs other types of data related to current utilized and voltage applied, which are indicative of torque imparted, then the controller64may use that data to determine the torque applied by the electric motor48using a program that may be stored in the memory68of the controller64.

Referring now toFIG. 8, a method72of adding a volume of water to the second washing compartment54(a removable washing compartment) of the washing machine10includes a step74of estimating or calculating the mass of the first set of articles44in the first washing compartment40. Before step74, the user will have loaded the first set of articles44into the first washing compartment40, while the second washing compartment54is in the removed position59. In embodiments, the controller64estimates or calculates the mass of the first set of articles44when the second washing compartment54is in the removed position59by estimating or calculating the moment of inertia of the first set of articles44.

In embodiments, the controller64estimates or calculates the moment of inertia of the first set of articles44(and, from the moment of inertia, the mass of the first set of articles44), at least in part by causing the first washing compartment40with the first set of articles44to rotate according to a rotational speed as a function of time profile as set forth inFIG. 9. First, the controller64causes the electric motor48to rotate the first washing compartment40at a first substantially constant rotational speed (ω1), after a ramp up period where the first washing compartment40is accelerated from a rest state to the first substantially constant rotational speed (ω1). Second, during a deceleration stage, the controller64controls the electric motor48to cause the rotational speed of the first washing compartment40(containing the first set of articles44) to decrease from the first substantially constant rotational speed (ω1) to a second substantially constant rotational speed (ω2) over a first period of time (Δt1) for an average deceleration (αdown) of

(ω1-ω2)Δt⁢1.
Third, during an acceleration phase, the controller64controls the electric motor48to cause the rotational speed of the first washing compartment40(containing the first set of articles44) to increase from the second substantially constant rotational speed (ω2) to the first substantially constant rotational speed (ω1) over a second period of time (Δt2) for an average acceleration (αup) of

(ω2-ω1)Δt⁢2.
The controller64then controls the electric motor48to decelerate the rotation of the first washing compartment40back to rest during a ramp down period (see path A,FIG. 9). The controller64maintains the first substantially constant rotational speed (ω1) and the second substantially constant rotational speed (ω2) at least long enough for the electric motor48to stabilize. The first washing compartment40with the first set of articles44is accelerated and decelerated in this manner while the first set of articles44are in their original “dry” state, that is, the washing machine10has not added a volume of water to the first washing compartment40yet. The first substantially constant rotational speed (ω1) and the second substantially constant rotational speed (ω2) can be any suitable speed and may be tuned to provide the best signal-to-noise ratio for data sensing, which depends on the particular configuration of the washing machine10. The average acceleration/deceleration (αupand αdown) can be any suitable acceleration or deceleration, and can have the same or different absolute values. In embodiments, the average acceleration/deceleration (αupand αdown) have the same absolute value.

In embodiments, the controller64estimates or calculates the moment of inertia of the first set of articles44(and, from the moment of inertia, the mass of the first set of articles44), at least in part by sensing, estimating, or calculating the torque (τdown) that the electric motor48outputs while causing the rotational speed of the first washing compartment40with the first set of articles44to decrease from the first substantially constant rotational speed (ω1) to the second substantially constant rotational speed (ω2) over the first period of time (Δt1). Similarly, In embodiments, the controller64estimates or calculates the moment of inertia of the first set of articles44(and, from the moment of inertia, the mass of the first set of articles44), at least in part by sensing, estimating, or calculating the torque (τup) that the electric motor48outputs while causing the rotational speed of the first washing compartment40with the first set of articles44to increase from the second substantially constant rotational speed (ω2) to the first substantially constant rotational speed (ω1) over the second period of time (Δt2). In other words, the controller64senses, estimates, or calculates the torque (τdown) that the electric motor48outputs during the deceleration stage and the torque (τup) that the electric motor48outputs during the acceleration phase. The torques (τdownand τup) that the controller64sense, estimate, or calculate can be the average torques during the deceleration stage and the acceleration stage, respectively.

For example, the motor torque sensor72a(e.g., the controller64that is part of the electric motor48), or other suitable sensor, may sense and output the relevant data to the controller64to allow the controller64to obtain, estimate, or calculate the torque data (τdownand τup) and acceleration data (αdownand αup) of the first washing compartment40during the deceleration stage and the acceleration phase for use in determining the moment of inertia of the first washing compartment40(with the first set of articles44). While the electric motor48decelerates and accelerates the first washing compartment40(with the first set of articles44) according to commands from the controller64, the actual deceleration and acceleration realized by the first washing compartment40will likely differ from the commanded acceleration and deceleration. As mentioned above, contemporary electric motors48often include their own controller that outputs data for such information. The electric motor48, for example, can provide torque data, which the electric motor48calculates as a function of electrical current and bus voltage. The electric motor48then outputs that data to the controller64. For some electric motors48, this data is not available directly from the electric motor48. When the data is not available, other values indicative of the torque may be used. For example, the torque may be proportional to a motor characteristic, such as the current of the electric motor48, for example, which may be used instead and as part of an estimation of the moment of inertia.

In embodiments, the controller64estimates or calculates the moment of inertia of the first set of articles44(and, from the moment of inertia, the mass of the first set of articles44), at least in part by estimating or calculating the moment of inertia of the first washing compartment40with the first set of articles44via an equation that divides (τup−τdown) by (αup−αdown). An example of such an equation is derived below. Generally, the torque that the electric motor48must output and impart to the first washing compartment40to rotate the first washing compartment40(with the first set of articles44) can be represented by equation (1) below:
τ=(Jfwc+fsa*α)+(B*ω)+C(1)
where τ is torque, Jfwc+fsais inertia of the combined first washing compartment40(“fwc”) and the first set of articles44(“fsa”), α is acceleration, B is a viscous damping (friction) coefficient unique to the washing machine10, ω is the rotational speed of the first washing compartment40, and C is the coulomb friction unique to the electric motor48and the washing machine10generally. It follows that the torque during the deceleration phase (τdown) and the acceleration phase (τup) are, respectively:
τdown=(Jfwc+fsa*αdown)+(B*ωdown)+C(2)
τup=(Jfwc+fsa*αup)+(B*ωup)+C(3)
The torque during the acceleration phase (τup) is greater than the torque during the deceleration phase (τdown), and the difference between the torques is represented in equation (4) below:
τup−τdown=((Jfwc+fsa*αup)+(B*ωup)+C)−((Jfwc+fsa*αdown)+(B*ωdown)+C(4)

The coulomb friction C is the same for both the deceleration phase and the acceleration phase and thus cancel out. If the ωdownand the ωupare considered as average rotational speeds of the first washing compartment40during the deceleration phase and the acceleration phase, respectively, and are equal, then the (B * ωdown)+C and the (B * ωup)+C portions of equation (4) are equal and cancel out. With the friction related aspects canceling out, the result is equation (5) below:
τup−τdown=Jfwc+fsa*(αup−αdown)  (5)
Note that in instances where the electric motor48does not output torque data directly to the controller64, the controller64can derive the torque during the acceleration phase (τup) and the torque during the deceleration phase (τdown) from sensor-less torque estimation techniques using motor current readings, or the average current of electricity that the electric motor48utilizes during the acceleration phase (Iup) and the average current of electricity that the electric motor48utilizes during the deceleration phase (Idown), respectively, because the torque that the electric motor48is delivering is proportional to the motor current. In any event, solving for the moment of inertia Jfwc+fsaof the first washing compartment40(with the first set of articles44) thus provides equation (6) below:

m⁢a⁢s⁢sf⁢s⁢a=Jf⁢s⁢ar2(8)
where r is an assumed radius of the first set of articles56inside the first washing compartment40relative to the axis52. In some circumstances, the mass of the first set of articles44as estimated or calculated using the model detailed above will differ from the actual mass of the first set of articles44, because of modeling imprecision and “noise”. Thus, the relationship between the mass of the first set of articles44estimated/calculated from the equation (8) and the model above and the true mass of the first set of articles44can be experimentally correlated, such that the model includes the controller64executing equation (9) below:
massfsa_actual=f(Jfsa)+N(9)
where massfsa_actualis the true mass of the first set of articles44, or at least a closer approximation thereof and N are the experimentally deduced noise factors, which, in embodiments, varies as a function of the model of the washing machine10. The noise factors (N) can be predicted using statistical modeling where it is experimentally or empirically tuned for a specific class or platform of products. The controller64can then cause the determined mass of the first set of articles44(massfsa_actual) to be stored in the memory68.

The method72further includes, at step76, estimating or calculating a mass of the second set of articles56in (i.e., held by) the second washing compartment54. This step76will occur after the second washing compartment54is placed into the inserted position58and the second set of articles56is loaded into the second washing compartment54. The controller64can prompt the user at the user interface34to place the second washing compartment54in the inserted position58, and to load the second set of articles56into the second washing compartment54. In embodiments, this step76occurs after step74but need not. The controller64can confirm that the lid26is in the closed position30before estimating or calculating the mass of the second set of articles56in the second washing compartment54.

At this point, in this embodiment, the washing machine10includes the first washing compartment40(holding the first set of articles44) and the second washing compartment54(holding the second set of articles56) in the inserted position58. At step74, the controller64already estimated or calculated the mass of the first set of articles44when the second washing compartment54was in the removed position59and stored that value in the memory68. Thus, in embodiments, to estimate or calculate the mass of the second set of articles56, the controller64: (i) estimates or calculates the collective mass of the first set of articles44and the second set of articles56when the second washing compartment54is in the inserted position58; and then (ii) subtracts the estimated or calculated mass of the first set of articles44stored in the memory68from the estimated or calculated collective mass of the first set of articles44and the second set of articles56.

In embodiments, to estimate or calculate the collective mass of the first set of articles44and the second set of articles56when the second washing compartment54is in the inserted position58, the controller64again performs the mathematics model detailed above to determine the moment of inertia of the first set of articles44and the second set of articles56combined. In embodiments, the controller64estimates or calculates the moment of inertia of the first set of articles44and the second set of articles56combined (and, from the moment of inertia, the mass of the first set of articles44and the mass of the second set of articles56combined), at least in part by causing the first washing compartment40(holding the first set of articles44) and the second washing compartment54(holding the second set of articles56) to rotate according to a rotational speed as a function of time profile as set forth inFIG. 9. First, the controller64causes the electric motor48to rotate the first washing compartment40and the second washing compartment54(holding the first set of articles44and the second set of articles56, respectively) at a first substantially constant rotational speed (ω1), after a ramp up period where the first washing compartment40and the second washing compartment54are accelerated from a rest state to the first substantially constant rotational speed (ω1). Second, during a deceleration stage, the controller64controls the electric motor48to cause the rotational speed of the first washing compartment40(containing the first set of articles44) and the second washing compartment54(containing the second set of articles56) to decrease from the first substantially constant rotational speed (ω1) to a second substantially constant rotational speed (ω2) over a first period of time (Δt1) for an average deceleration (αdown) of (ω1−ω2)/Δt1. Third, during an acceleration phase, the controller64controls the electric motor48to cause the rotational speed of the first washing compartment40(containing the first set of articles44) and the second washing compartment54(containing the second set of articles56) to increase to the first substantially constant rotational speed (ω1) over a second period of time (Δt2) for an average acceleration (αup) of (ω2−ω1)/Δt2. In embodiments, the controller48then controls the electric motor48to maintain the first substantially constant rotational speed (ω1) (see path B,FIG. 9) until the controller48initiate a subsequent sensing iteration or some other step of the washing operation.

In embodiments, the controller64estimates or calculates the collective moment of inertia of the first set of articles44and the second set of articles56(and, from the moment of inertia, the combined mass of the first set of articles44and the second set of articles56) when the second washing compartment54is in the inserted position58and the second set of articles56is disposed in the second washing compartment54at least in part by calculating the torque (τdown) that the electric motor48outputs while causing the rotational speed of the first washing compartment40with the first set of articles44and the second washing compartment54with the second set of articles56to decrease from the first substantially constant rotational speed (ω1) to the second substantially constant rotational speed (ω2) over the first period of time (Δt1). Similarly, In embodiments, the controller64estimates or calculates the collective moment of inertia of the first set of articles44and the second set of articles56(and, from the moment of inertia, the combined mass of the first set of articles44and the second set of articles56) when the second washing compartment54is in the inserted position58and the second set of articles56is disposed in the second washing compartment54at least in part by calculating the torque (τup) that the electric motor48outputs while causing the rotational speed of the first washing compartment40with the first set of articles44and the second washing compartment54with the second set of articles56to increase from the second substantially constant rotational speed (ω2) to the first substantially constant rotational speed (ω1) over the second period of time (Δt2). In other words, the controller64senses, estimates, or calculates the torque (τdown) that the electric motor48outputs during the deceleration stage and the torque (τup) that the electric motor48outputs during the acceleration phase. The torques (τdown) and τup) that the controller64sense, estimate, or calculate can be the average torques during the deceleration stage and the acceleration stage, respectively. Note that in instances where the electric motor48does not output torque data directly to the controller64, the controller64can derive the torques during the acceleration phase (τup) and the torque during the deceleration phase (τdown) from the average current of electricity that the electric motor48utilizes during the acceleration phase (Iup) and the average current of electricity that the electric motor48utilizes during the deceleration phase (Idown), respectively, because the torque that the electric motor48is delivering is proportional to the current.

In embodiments, the controller64estimates or calculates the moment of inertia of the first set of articles44and the second set of articles56collectively (and, from the moment of inertia, the collective mass of the first set of articles44and the second set of articles56), at least in part by estimating or calculating the moment of inertia of the first washing compartment40with the first set of articles44and the second washing compartment54with the second set of articles56via an equation that divides (τup−τdown) by (αup−αdown). An example of such an equation was derived above and the same principles apply now. However, note that the equation (10), reproduced below, will be the moment of inertia Jtotalof the first washing compartment40(with the first set of articles44) and the second washing compartment54(with the second set of articles56) collectively:

m⁢a⁢s⁢ss⁢s⁢a=Js⁢s⁢ar2(13)
where r is an assumed radius of the second set of articles56inside the second washing compartment54relative to the axis52. In other words, estimating or calculating the mass of the second set of articles56(massssa) in the second washing compartment54includes, at least in part, estimating or calculating: (a) the moment of inertia (Jfwc+fsa) of the first washing compartment40and the first set of articles44when the second washing compartment54is in the removed position59; (b) the collective moment of inertia (Jtotal) of the first washing compartment40, the first set of articles44, the second washing compartment54, and the second set of articles56when the second washing compartment is in the inserted position58; and (c) subtracting (a) from (b) as in equation (12). Again, in some circumstances, the mass of the second set of articles56as estimated or calculated using the model detailed above will differ from the actual mass of the second set of articles56, because of modeling imprecision (such as that surrounding equation (13)) and “noise”. Thus, the relationship between the mass of the second set of articles56estimated/calculated from the equation (13) and the model above and the true mass of the second set of articles56can be experimentally correlated, such that the model includes the controller64executing equation (14) below:
massssa_actual=f(Jssa)+N(14)
where massssa_actualis the true mass of the second set of articles56, or at least a better closer approximation thereof and N are the experimentally deduced noise factors, which will likely depend on the washing machine10. The noise factors (N) can be predicted using statistical modeling where it is experimentally or empirically tuned for a specific class or platform of products. The controller64can then cause the determined mass of the second set of articles56(massssa_actual) to be stored in the memory68.

The method72further includes, at step78, adding a second volume of water to the second washing compartment54, without causing water added to the second washing compartment54to overflow from the second washing compartment54into the first washing compartment40. The second volume of water is determined as a function of the estimated or calculated mass of the second set of articles56. In embodiments, the second volume of water (Vsecond) is determined according to equation (15) below:
Vsecond=f(masssac_model)  (15)
The second volume of water (Vsecond) can be experimentally correlated with the mass of the second set of articles56(masssac_model), and, in some instances, will depend on the geometry of the second washing compartment54. In embodiments, the second volume of water is proportional to the mass of the second set of articles56, will be of sufficient volume to allow for the laundering of the second set of articles56, but will not overflow into the first washing compartment40.

The method72further includes, at step80, adding a first volume of water to the first washing compartment40. Note that this step can occur simultaneously with or before step78. The first volume of water is determined as a function of the estimated or calculated mass of the first set of articles44. In embodiments, the first volume of water (Vfirst) is determined according to equation (16) below:
Vfirst=f(massfsa_actual)  (16)
The first volume of water (Vfirst) can be experimentally correlated with the mass (massfsa_actual) of the first set of articles44, and, in embodiments, depend on the geometry of the first washing compartment40. In embodiments, the first volume of water is proportional to the mass of the first set of articles44and will be of sufficient volume to allow for laundering of the first set of articles44, but not an excessive volume.

In a variation of the method72, after step74, instead of proceeding to step76, the method72proceeds to step82. At step82, the method72further includes the first washing compartment40and the second washing compartment54to rotate together at a predetermined rotational speed (ωpre). The second washing compartment54is in the inserted position58after step74and contains the second set of articles56, and, as described in connection with step73, the first washing compartment50includes the first set of articles44. The controller64can cause the electric motor48to rotate the first washing compartment40and the second washing compartment54at the predetermined rotational speed (ωpre).

Next, at step84, liquid from the external liquid source62flows from the external liquid source62and into the second washing compartment54while the first washing compartment40and the second washing compartment54are rotating at the predetermined rotational speed. The liquid can be water. The controller64can cause the liquid flow valve60to cause the liquid to flow into the second washing compartment54.

Next, at step86, the electric motor48is caused (such as via the controller64controlling the electric motor48) to maintain rotating the first washing compartment40and the second washing compartment54at the predetermined rotational speed (ωpre) as liquid flows into the second washing compartment54, while monitoring the moment of inertia of the second washing compartment54together with the second set of articles56and the liquid in the second washing compartment54. The moment of inertia of the first washing compartment40with the first set of articles44was determined in step74and, thus, the moment of inertia of the second washing compartment54together with the second set of articles56and the liquid in the second washing compartment54can be repeatedly calculated and monitored. In embodiments, the controller64can monitor the moment of inertia of the second washing compartment54together with the second set of articles56and the liquid in the second washing compartment54as detailed above in the lead up to and including equation (11). The only difference is that the moment of inertia is a product of the mass of the liquid added to the second washing compartment54, in addition to the second set of articles56and the second washing compartment54itself. However, the controller64can repeatedly determine the moment of inertia in any suitable manner. In embodiments, the controller64determines a rate of change of the repeatedly determined moment of inertia. Moments of inertia may be determined in a variety of ways and additional description of methods for determining inertia may be found in U.S. Pat. No. 9,540,756; United States Patent Application Publication No. US20150047396A1; and U.S. Pat. No. 9,091,011, which are incorporated herein by reference in their entireties.

Next, at step88, as the moment of inertia meets or exceeds a predetermined value, or the rate of change of the moment of inertia satisfies a predetermined threshold, the electric motor48(such as from a command from the controller64) stops rotating the first washing compartment40and the second washing compartment54and to stop liquid from flowing from the liquid supply system into the second washing compartment54. In embodiments, these threshold values are stored in the memory68of the controller64. The predetermined value of the moment of inertia represents a combined mass of the second set of articles56and the volume of liquid added to the second washing compartment54that has a sufficient volume of liquid to wash the second set of articles56but insufficient volume of liquid to cause the liquid to overflow into the first washing compartment40. The method72then proceeds to step80, where a volume of liquid is added to the first washing compartment40as a function of the determined mass of the first set of articles44.

After the method72is complete, the washing machine10then completes a wash cycle and any other desired functions to launder the first set of articles44and the second set of articles56.

According to one aspect of the present disclosure, a washing machine includes a tub. A first washing compartment is disposed within the tub to hold a first set of articles to be washed, the first set of articles having a mass. A second washing compartment holds a second set of articles to be washed, the second set of articles having a mass, the second washing compartment having an inserted position and a removed position. A liquid flow valve is configured to connect to an external liquid source to selectively control flow of liquid from the external liquid source and into either the first washing compartment, the second washing compartment, or both the first washing compartment and the second washing compartment. An electric motor is operably coupled to and configured to cause the first washing compartment to rotate, and operably coupled to and configured to cause the second washing compartment to rotate when the second washing compartment is in the inserted position but not in the removed position. A controller is in communication with the electric motor that estimates or calculates the mass of the second set of articles held by the second washing compartment and then calculates, as a function of the estimated or calculated mass of the second set of articles, a volume of water to be added to the second washing compartment.

According to another aspect of the present disclosure, the controller estimates or calculates the mass of the second set of articles (massssa) at least in part by: (i) estimating or calculating a moment of inertia (Jfwc+fsa) of the first washing compartment and the first set of articles when the second washing compartment is in the removed position; and (ii) estimating or calculating the collective moment of inertia (Jtotal) of the first washing compartment, the first set of articles, the second washing compartment, and the second set of articles when the second washing compartment is in the inserted position; and then (iii) subtracting (i) from (ii).

According to another aspect of the present disclosure, the electric motor includes a shaft that rotates about an axis and that is operably connected to the first washing compartment such that as the electric motor causes the shaft to rotate about the axis, the first washing compartment also rotates about the axis; and the controller estimates or calculates the mass of the first set of articles when the second washing compartment is in the removed position at least in part by: (i) causing the first washing compartment with the first set of articles to rotate at a first substantially constant rotational speed (ω1); (ii) causing the rotational speed of the first washing compartment with the first set of articles to decrease to a second substantially constant rotational speed (ω2) over a first period of time (Δt1) for an average deceleration (αdown) of (ω1−ω2)/Δt1; and (iii) causing the rotational speed of the first washing compartment with the first set of articles to increase from the second substantially constant rotational speed (ω2) to the first substantially constant rotational speed (ω1) over a second period of time (Δt2) for an average acceleration (αup) of (αup)/Δt2.

According to another aspect of the present disclosure, the controller estimates or calculates the mass of the first set of articles when the second washing compartment is in the removed position at least in part by sensing, estimating, or calculating a torque (τdown) that the electric motor outputs while causing the rotational speed of the first washing compartment with the first set of articles to decrease from the first substantially constant rotational speed (ω1) to the second substantially constant rotational speed (ω2) over the first period of time (Δt1).

According to another aspect of the present disclosure, the controller estimates or calculates the mass of the first set of articles when the second washing compartment is in the removed position at least in part by sensing, estimating, or calculating a torque (τup) that the electric motor outputs while causing the rotational speed of the first washing compartment with the first set of articles to increase from the second substantially constant rotational speed (ω2) to the first substantially constant rotational speed (ω1) over the second period of time (Δt2).

According to another aspect of the present disclosure, the controller estimates or calculates the mass of the first set of articles when the second washing compartment is in the removed position at least in part by estimating or calculating a moment of inertia of the first washing compartment with the first set of articles via an equation that divides (τup−τdown) by (αup−αdown).

According to another aspect of the present disclosure, the controller derives the torque during an acceleration phase (τup) and the torque during a deceleration phase (τdown) from an average current of electricity that the electric motor utilizes during the acceleration phase (Iup) and the average current of electricity that the electric motor utilizes during the deceleration phase (Idown), respectively.

According to another aspect of the present disclosure, the electric motor is additionally operably connected to the second washing compartment such that as the electric motor causes the shaft to rotate about the axis, both the first washing compartment and the second washing compartment also rotate about the axis; and the controller estimates or calculates the collective mass of the first set of articles and the second set of articles when the second washing compartment is in the inserted position and the second set of articles is disposed in the second washing compartment at least in part by: (i) causing the first washing compartment with the first set of articles and the second washing compartment with the second set of articles to rotate at a first substantially constant rotational speed (ω1); (ii) causing the rotational speed of the first washing compartment with the first set of articles and the second washing compartment with the second set of articles to decrease to a second substantially constant rotational speed (ω2) over a first period of time (Δt1) for an average deceleration (αdown) of (ω1−ω2)/Δt1; and (iii) causing the rotational speed of the first washing compartment with the first set of articles and the second washing compartment with the second set of articles to increase to the first substantially constant rotational speed (ω1) over a second period of time (Δt2) for an average acceleration (αup) of (ω2−ω1)/Δt2.

According to another aspect of the present disclosure, the controller estimates or calculates the collective mass of the first set of articles and the second set of articles when the second washing compartment is in the inserted position and the second set of articles is disposed in the second washing compartment at least in part by calculating a torque (τdown) that the electric motor outputs while causing the rotational speed of the first washing compartment with the first set of articles and the second washing compartment with the second set of articles to decrease from the first substantially constant rotational speed (ω1) to the second substantially constant rotational speed (ω2) over the first period of time (Δt1).

According to another aspect of the present disclosure, the controller estimates or calculates the collective mass of the first set of articles and the second set of articles when the second washing compartment is in the inserted position and the second set of articles is disposed in the second washing compartment at least in part by calculating a torque (τup) that the electric motor outputs while causing the rotational speed of the first washing compartment with the first set of articles and the second washing compartment with the second set of articles to increase from the second substantially constant rotational speed (ω2) to the first substantially constant rotational speed (ω1) over the second period of time (Δt2).

According to another aspect of the present disclosure, the controller estimates or calculates the collective mass of the first set of articles and the second set of articles when the second washing compartment is in the inserted position and the second set of articles is disposed in the second washing compartment at least in part by estimating or calculating a moment of inertia of the first washing compartment with the first set of articles and the second washing compartment with the second set of articles via an equation that divides (τup−τdown) by (αup−αdown).

According to another aspect of the present disclosure, the controller derives the torque during the acceleration phase (τup) and the torque during the deceleration phase (τdown) from the average current of electricity that the electric motor utilizes during the acceleration phase (Iup) and the average current of electricity that the electric motor utilizes during the deceleration phase (Idown), respectively.

According to yet another aspect of the present disclosure, a washing machine includes a tub. A first washing compartment is disposed within the tub to hold a first set of articles to be washed, the first set of articles having a mass. A second washing compartment holds a second set of articles to be washed, the second set of articles having a mass, the second washing compartment having an inserted position and a removed position. A liquid flow valve is configured to connect to an external liquid source to selectively control flow of liquid from the external liquid source and into either the first washing compartment, the second washing compartment, or both the first washing compartment and the second washing compartment. An electric motor is operably coupled to and configured to cause the first washing compartment to rotate, and operably coupled to and configured to cause both the first washing compartment and the second washing compartment to rotate when the second washing compartment is in the inserted position but not in the removed position. A controller is in communication with the electric motor and is configured to: (a) to cause the electric motor to rotate together the first washing compartment and the second washing compartment at a predetermined rotational speed when the second washing compartment is in the inserted position and contains the second set of articles; (b) to cause liquid to flow from the external liquid source and into the second washing compartment while the second washing compartment is rotating at the predetermined rotational speed; (c) to cause the electric motor to maintain rotating the first washing compartment and the second washing compartment at the predetermined rotational speed, while the monitoring the moment of inertia of the second washing compartment together with the second set of articles and the liquid in the second washing compartment; and (d) as the moment of inertia meets or exceeds a predetermined value, or as the moment of inertia meets or exceeds a predetermined rate of change, to cause the electric motor to stop rotating the first washing compartment and the second washing compartment and to stop liquid from flowing from a liquid supply system into the second washing compartment.

According to yet another aspect of the present disclosure, the controller is further configured to estimate or calculate the mass of the first set of articles in the first washing compartment, when the second washing compartment is in the removed position.

According to yet another aspect of the present disclosure, the controller is configured to estimate or calculate the mass of the first set of articles in the first washing compartment by manipulating the electric motor: (i) to cause the first washing compartment with the first set of articles to rotate at a first substantially constant rotational speed (ω1); (ii) to cause the rotational speed of the first washing compartment with the first set of articles to decrease to a second substantially constant rotational speed (ω2) over a first period of time (Δt1) for an average deceleration (αdown) of (ω1−ω2)/Δt1; and (iii) to cause the rotational speed of the first washing compartment with the first set of articles to increase to the first substantially constant rotational speed (ω1) over a second period of time (Δt2) for an average acceleration (αup) of (ω2−ω1)/Δt2.

According to yet another aspect of the present disclosure, the controller is configured: (d) as the moment of inertia meets or exceeds a predetermined rate of change, to cause the electric motor to stop rotating the first washing compartment and the second washing compartment and to stop liquid from flowing from a liquid supply system into the second washing compartment.

According to still yet another aspect of the present disclosure, a method of adding a volume of water to a removable washing compartment of a washing machine includes after a first set of articles is loaded into a first washing compartment of a washing machine and while a second washing compartment of the washing machine is in a removed position, estimating or calculating a mass of the first set of articles in the first washing compartment; after the second washing compartment is placed into an inserted position and a second set of articles is loaded into the second washing compartment, estimating or calculating a mass of the second set of articles in the second washing compartment; adding a second volume of water to the second washing compartment, without causing water added to the second washing compartment to overflow from the second washing compartment into the first washing compartment, the second volume of water determined as a function of the estimated or calculated mass of the second set of articles; and adding a first volume of water to the first washing compartment, the first volume of water determined as a function of the estimated or calculated mass of the first set of articles.

According to still yet another aspect of the present disclosure, estimating or calculating a mass of the first set of articles in the first washing compartment includes causing an electric motor of the washing machine to rotate the first washing compartment about an axis and evaluating one or more of: (i) torque that the electric motor outputs while rotating the first washing compartment; (ii) rotational acceleration and/or deceleration of the first washing compartment; (iii) the moment of inertia of the first washing compartment while the electric motor rotates the first washing compartment; and (iv) the electrical current that the electric motor is utilizing while the electric motor rotates the first washing compartment.

According to still yet another aspect of the present disclosure, estimating or calculating a mass of the second set of articles in the second washing compartment includes causing the electric motor of the washing machine to rotate the first washing compartment together with the second washing compartment about an axis and evaluating one or more of: (i) torque that the electric motor outputs while rotating the first washing compartment together with the second washing compartment; (ii) rotational acceleration and/or deceleration of the first washing compartment together with the second washing compartment; (iii) moment(s) of inertia of the first washing compartment together with the second washing compartment while the electric motor rotates the first washing compartment together with the second washing compartment; and (iv) electrical current that the electric motor is utilizing while the electric motor rotates the first washing compartment together with the second washing compartment.

According to still yet another aspect of the present disclosure, estimating or calculating a mass of the second set of articles in the second washing compartment includes determining: (a) the moment of inertia of the first washing compartment and the first set of articles; (b) the moment of inertia of the first washing compartment, the first set of articles, the second washing compartment, and the second set of articles together; and (c) subtracting (a) from (b).