Patent Grant
11242633
The present subject matter relates generally to washing machine appliances, such as horizontal axis washing machine appliances, and methods for monitoring load balances in such washing machine appliances.
Washing machine appliances generally include a wash tub for containing water or wash fluid (e.g., water and detergent, bleach, or other wash additives). A basket is rotatably mounted within the wash tub and defines a wash chamber for receipt of articles for washing. During normal operation of such washing machine appliances, the wash fluid is directed into the wash tub and onto articles within the wash chamber of the basket. The basket or an agitation element can rotate at various speeds to agitate articles within the wash chamber, to wring wash fluid from articles within the wash chamber, etc. Washing machine appliances include vertical axis washing machine appliances and horizontal axis washing machine appliances, where “vertical axis” and “horizontal axis” refer to the axis of rotation of the wash basket within the wash tub.
A significant concern during operation of washing machine appliances is the balance of the tub during operation. For example, articles and water loaded within a basket may not be equally weighted about a central axis of the basket and tub. Accordingly, when the basket rotates, in particular during a spin cycle, the imbalance in clothing weight may cause the basket to be out-of-balance within the tub, such that the axis of rotation does not align with the cylindrical axis of the basket or tub. Such out-of-balance issues can cause the basket to contact the tub during rotation, and can further cause movement of the tub within the cabinet. Significant movement of the tub can, in turn, cause excessive noise, vibration or motion, or damage to the appliance.
Various methods are known for monitoring load balances and preventing out-of-balance scenarios within washing machine appliances. Such monitoring and prevention may be especially important, for instance, during the high-speed rotation of a plaster phase of a spin cycle that ensures water is shed from articles within the tub. Typical systems guess when articles within the tub are in a suitable position for the plaster phase based on monitored motor current or rotational velocity. One or more balancing rings may be attached to the rotating basket to provide a rotating annular mass that minimizes the effects of imbalances. However, such systems may fail to accurately determine the position of articles within the tub or basket. Moreover, in the case of balancing rings, such systems may increase the amount of energy or torque required to rotate the basket, thereby decreasing efficiency.
Accordingly, improved methods and apparatuses for monitoring load balance in washing machine appliances are desired. In particular, methods and apparatuses that provide for accurate detection of a balanced state or compensation for an imbalanced state during a washing operation would be advantageous.
Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In one exemplary aspect of the present disclosure, a method of operating a washing machine appliance is provided. The washing machine appliance has a tub. The method includes rotating articles within the tub at a tumble speed for a first period and rotating articles within the tub at a pre-plaster speed for a second period following the first period. The pre-plaster speed is greater than the tumble speed. The method also includes measuring movement of the tub during the second period. The method further includes determining a first out-of-balance value of the tub based on a first measured movement, determining a second out-of-balance value of the tub based on a second measured movement after the first measured movement, and determining a relative out-of-balance value of the tub based on the first out-of-balance value and the second out-of-balance value. The method then includes determining whether the relative out-of-balance value is less than a first threshold and whether the second out-of-balance value is less than a second threshold. When the relative out-of-balance value is less than the first threshold and the second out-of-balance value is less than the second threshold, the method includes rotating articles within the tub at a plaster speed greater than the pre-plaster speed in response to such determination.
In another exemplary aspect of the present disclosure, a method of operating a washing machine appliance is provided. The washing machine appliance defines a mutually-orthogonal vertical direction, transverse direction, and lateral direction. The washing machine appliance has a tub within which an axis of rotation is defined. The method includes rotating articles within the tub at a tumble speed for a first period and rotating articles within the tub at a pre-plaster speed for a second period following the first period. The pre-plaster speed is greater than the tumble speed. The method also includes measuring movement of the tub along the lateral direction during the second period. The lateral direction is perpendicular to the axis of rotation. The method also includes determining a plurality of out-of-balance values of the tub based on the measured movement. The plurality of out-of-balance values include a current out-of-balance value and a previous out-of-balance value. The method further includes determining a relative out-of-balance value of the tub based on the plurality of out-of-balance values. The method then includes determining whether the relative out-of-balance value is less than a first threshold and whether the current out-of-balance value is less than a second threshold. When the relative out-of-balance value is less than the first threshold and the current out-of-balance value is less than the second threshold, the method includes rotating articles within the tub at a plaster speed greater than the pre-plaster speed in response to such determination.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.
Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
In order to aid understanding of this disclosure, several terms are defined below. The defined terms are understood to have meanings commonly recognized by persons of ordinary skill in the arts relevant to the present invention. The terms “includes” and “including” are intended to be inclusive in a manner similar to the term “comprising.” Similarly, the term “or” is generally intended to be inclusive (i.e., “A or B” is intended to mean “A or B or both”). The terms “first,” “second,” and “third” may be used interchangeably to distinguish one element from another and are not intended to signify location or importance of the individual elements.
Referring now to the figures,
Referring to
A wash basket 120 is received within wash tub 124 and defines a wash chamber 126 that is configured for receipt of articles for washing. More specifically, wash basket 120 is rotatably mounted within wash tub 124 such that it is rotatable about an axis of rotation A. According to the illustrated embodiment, the axis of rotation is substantially parallel to the transverse direction T. In this regard, washing machine appliance 100 is generally referred to as a “horizontal axis” or “front load” washing machine appliance 100. However, it should be appreciated that aspects of the present subject matter may be used within the context of a vertical axis or top load washing machine appliance as well.
Wash basket 120 may define one or more agitator features that extend into wash chamber 126 to assist in agitation and cleaning of articles disposed within wash chamber 126 during operation of washing machine appliance 100. For example, as illustrated in
Washing machine appliance 100 includes a motor assembly 122 that is in mechanical communication with wash basket 120 to selectively rotate wash basket 120 (e.g., during an agitation or a rinse cycle of washing machine appliance 100). According to the illustrated embodiment, motor assembly 122 is a pancake motor. However, it should be appreciated that any suitable type, size, or configuration of motor may be used to rotate wash basket 120 according to alternative embodiments. Motor assembly will be described in further detail below.
Referring generally to
In some embodiments, a window 136 in door 134 permits viewing of wash basket 120 when door 134 is in the closed position (e.g., during operation of washing machine appliance 100). Door 134 also includes a handle (not shown) that, for example, a user may pull when opening and closing door 134. Further, although door 134 is illustrated as mounted to front panel 130, it should be appreciated that door 134 may be mounted to another side of cabinet 102 or any other suitable support according to alternative embodiments. Additionally or alternatively, a front gasket or baffle 138 may extend between tub 124 and the front panel 130 about the opening 132 covered by door 134, further sealing tub 124 from cabinet 102.
Referring again to
Turning briefly to
Returning to
As illustrated, a detergent drawer 152 may be slidably mounted within front panel 130. Detergent drawer 152 receives a wash additive (e.g., detergent, fabric softener, bleach, or any other suitable liquid or powder) and directs the fluid additive to wash chamber 126 during operation of washing machine appliance 100. According to the illustrated embodiment, detergent drawer 152 may also be fluidly coupled to spout 150 to facilitate the complete and accurate dispensing of wash additive.
In optional embodiments, a bulk reservoir 154 is disposed within cabinet 102. Bulk reservoir 154 may be configured for receipt of fluid additive for use during operation of washing machine appliance 100. Moreover, bulk reservoir 154 may be sized such that a volume of fluid additive sufficient for a plurality or multitude of wash cycles of washing machine appliance 100 (e.g., five, ten, twenty, fifty, or any other suitable number of wash cycles) may fill bulk reservoir 154. Thus, for example, a user can fill bulk reservoir 154 with fluid additive and operate washing machine appliance 100 for a plurality of wash cycles without refilling bulk reservoir 154 with fluid additive. A reservoir pump 156 is configured for selective delivery of the fluid additive from bulk reservoir 154 to wash tub 124.
A control panel 160 including a plurality of input selectors 162 is coupled to front panel 130. Control panel 160 and input selectors 162 collectively form a user interface input for operator selection of machine cycles and features. For example, in one embodiment, a display 164 indicates selected features, a countdown timer, or other items of interest to machine users.
Operation of washing machine appliance 100 is controlled by a controller or processing device 166 that is operatively coupled to control panel 160 for user manipulation to select washing machine cycles and features. In response to user manipulation of control panel 160, controller 166 operates the various components of washing machine appliance 100 to execute selected machine cycles and features.
Controller 166 may include a memory (e.g., non-transitive memory) and microprocessor, such as a general or special purpose microprocessor operable to execute programming instructions or micro-control code associated with a wash operation. The memory may represent random access memory such as DRAM, or read only memory such as ROM or FLASH. In one embodiment, the processor executes programming instructions stored in memory. The memory may be a separate component from the processor or may be included onboard within the processor. Alternatively, controller 166 may be constructed without using a microprocessor (e.g., using a combination of discrete analog or digital logic circuitry, such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software. Control panel 160 and other components of washing machine appliance 100, such as motor assembly 122 and measurement device 180 (discussed herein), may be in communication with controller 166 via one or more signal lines or shared communication busses. Optionally, measurement device 180 may be included with controller 166. Moreover, measurement devices 180 may include a microprocessor that performs the calculations specific to the measurement of motion with the calculation results being used by controller 166.
In exemplary embodiments, during operation of washing machine appliance 100, laundry items are loaded into wash basket 120 through opening 132, and a wash operation is initiated through operator manipulation of input selectors 162. For example, a wash cycle may be initiated such that wash tub 124 is filled with water, detergent, or other fluid additives (e.g., via additive dispenser 150). One or more valves (not shown) can be controlled by washing machine appliance 100 to provide for filling wash basket 120 to the appropriate level for the amount of articles being washed or rinsed. By way of example, once wash basket 120 is properly filled with fluid, the contents of wash basket 120 can be agitated (e.g., with ribs 128) for an agitation phase of laundry items in wash basket 120. During the agitation phase, the basket 120 may be motivated about the axis of rotation A at a set speed (e.g., first speed or tumble speed). As the basket 120 is rotated, articles within the basket 120 may be lifted and permitted to drop therein.
After the agitation phase of the washing operation is completed, wash tub 124 can be drained. Laundry articles can then be rinsed (e.g., through a rinse cycle) by again adding fluid to wash tub 124, depending on the particulars of the cleaning cycle selected by a user. Ribs 128 may again provide agitation within wash basket 120. One or more spin cycles may also be used. In particular, a spin cycle may be applied after the wash cycle or after the rinse cycle in order to wring wash fluid from the articles being washed. During a spin cycle, basket 120 is rotated at relatively high speeds. For instance, basket 120 may be rotated at one set speed (e.g., second speed or pre-plaster speed) before being rotated at another set speed (e.g., third speed or plaster speed). As would be understood, the pre-plaster speed may be greater than the tumble speed and the plaster speed may be greater than the pre-plaster speed. Moreover, agitation or tumbling of articles may be reduced as basket 120 increases its rotational velocity such that the plaster speed maintains the articles at a generally fixed position relative to basket 120.
After articles disposed in wash basket 120 are cleaned (or the washing operation otherwise ends), a user can remove the articles from wash basket 120 (e.g., by opening door 134 and reaching into wash basket 120 through opening 132).
Referring now to
A measurement device 180 in accordance with the present disclosure may include an accelerometer which measures translational motion, such as acceleration along one or more directions. Additionally or alternatively, a measurement device 180 may include a gyroscope, which measures rotational motion, such as rotational velocity about an axis. A measurement device 180 in accordance with the present disclosure is mounted to the tub 124 (e.g., on a sidewall of tub 124) to sense movement of the tub 124 relative to the cabinet 102 by measuring uniform periodic motion, non-uniform periodic motion, or excursions of the tub 124 during appliance 100 operation. For instance, movement may be measured as discrete identifiable components (e.g., in a predetermined direction).
In exemplary embodiments, a measurement device 180 may include at least one gyroscope or at least one accelerometer. The measurement device 180, for example, may be a printed circuit board that includes the gyroscope and accelerometer thereon. The measurement device 180 may be mounted to the tub 124 (e.g., via a suitable mechanical fastener, adhesive, etc.) and may be oriented such that the various sub-components (e.g., the gyroscope and accelerometer) are oriented to measure movement along or about particular directions as discussed herein. Notably, the gyroscope and accelerometer in exemplary embodiments are advantageously mounted to the tub 124 at a single location (e.g., the location of the printed circuit board or other component of the measurement device 180 on which the gyroscope and accelerometer are grouped). Such positioning at a single location advantageously reduces the costs and complexity (e.g., due to additional wiring, etc.) of out-of-balance detection, while still providing relatively accurate out-of-balance detection as discussed herein. Alternatively, however, the gyroscope and accelerometer need not be mounted at a single location. For example, a gyroscope located at one location on tub 124 can measure the rotation of an accelerometer located at a different location on tub 124, because rotation about a given axis is the same everywhere on a solid object such as tub 124.
As illustrated, tub 124 may define an X-axis, a Y-axis, and a Z-axis that are mutually orthogonal to each other. The Z-axis may extend along a longitudinal direction, and may thus be coaxial or parallel with the axis of rotation A (
In some embodiments, movement is measured as a plurality of unique displacements values. Optionally, the displacement values may occur in discrete channels of motion (e.g., as distinct directional components of movement). For instance, displacement values may correspond to one or more indirectly measured movement components perpendicular or approximately perpendicular to a center C (e.g., geometric center of gravity based on the shape and mass of tub 124 in isolation) of the tub 124. Such movement components may, for example, occur in a plane defined by the X-axis and Y-axis (i.e., the X-Y plane) or in a plane perpendicular to the X-Y plane. Movement of the tub 124 along the particular direction may be calculated using the indirect measurement component and other suitable variables, such as a horizontal or radial offset distance along the vector from the measurement device 180 to the center C of the tub 124. Additionally or alternatively, the displacement values may correspond to one or more directly measured movement components. Such movement components may, for example, occur in the X-Y plane or in a plane perpendicular to the X-Y plane.
The measured movement of the tub 124 in accordance with exemplary embodiments of the present disclosure, such as those requiring one or more gyroscopes and one or more accelerometers, may advantageously be calculated based on the movement components measured by the accelerometer or gyroscope of the measurement device(s) 180. For example, a movement component of the tub 124 may be a linear displacement vector PXB (e.g., a first displacement vector) of center C in the X-Y plane (e.g., along the lateral direction L). Displacement vector PXB may be calculated from detected movement by the accelerometer at measurement device 180 (e.g., via double integration of detected acceleration data). For example, vectors defined in an X-Y plane such as PXB may represent the radius of a substantially circular (e.g., elliptical, orbital, or perfectly circular) motion caused by the rotation of an imbalanced load so that maximum and minimum values of the periodic vector occur as the substantially circular motion aligns with the direction of the vector.
In additional or alternative embodiments, another movement component of tub 124 is obtained at measurement device 180. For instance, a wobble angle ϕYY of angular displacement of the tub 124 may be calculated. Wobble angle ϕYY may represent rotation relative to the axis of rotation A (
In still further additional or alternative embodiments, a movement component of tub 124 may be a linear displacement vector PXT (e.g., a second displacement vector) of a center C′ (e.g., effective center of gravity that compensates for biasing or resistance forces on tub 124 from one or more directions) in a plane parallel to the X-Y plane and perpendicular to the axis of rotation A (
Notably, the term “approximately” as utilized with regard to the orientation and position of such movement measurements denotes ranges such as of plus or minus 2 inches or plus or minus 10 degrees relative to various axes passing through the basket center C which minimizes, for example, the contribution to error in the measurement result by rotation about the Z-axis, as might be caused, for example, by a torque reaction to motor assembly 122.
Further, and as discussed, the measurement device 180 need not be in the X-Y plane in which movement (e.g., at the center C) is calculated. For example, measurement device 180 may additionally be offset by an offset distance along the Z-axis. In one particular example, a measurement device 180 mounted to or proximate a suspension assembly 170 may be utilized to indirectly measure movement of the center C in an X-Y plane at or proximate the top of the tub 124. Additionally or alternatively, a measurement device 180 can be mounted close to or on the Z-axis or may be used to calculate motion that is not on the axis of rotation A (
In some embodiments, an out-of-balance (OOB) value may be determined, at least in part, from the movement measured from measurement device 180. For instance, controller 166 may correlate displacement (e.g., as measured in inches) and rotational velocity (e.g., as measured at motor assembly 122 in rotations per minute) to an OOB value, such as a value of weight or mass (e.g., in pounds-mass). Advantageously, the determined OOB value may provide an accurate indicator of an imbalance that accounts for both displacement and rotation. In some such embodiments, a predetermined graph, table, or transfer function may be provided to determine a specific OOB value using a known or measured displacement value and rotational velocity. The predetermined graph, table, or transfer function may be determined from experimental data and, optionally, included within controller 166.
As an example, the OOB value may be determined from a transfer function provided as
OOB=PXT*(Q1*VR+Q2)+(Q3*VR)−Q4
wherein:
PXT is a measured displacement;
VR is a measured or otherwise known rotational velocity; and
Q1, Q2, Q3, and Q4 are each unique predetermined coefficients relating to the corresponding washer appliance.
In optional embodiments, controller 166 may gather multiple OOB values (e.g., continuously or over a set period of time). From these multiple OOB values, controller 166 may determine a rate of change for the OOB values. For instance, controller 166 may calculate a rate of change across multiple OOB values spanning a sub-period of time. Additionally or alternatively, controller 166 may graph the OOB values and determine a slope of the graphed values at a specific point in time. Thus, in various embodiments, a relative displacement value or relative OOB value may be calculated based on one or both of the rate of change and/or the slope.
Referring now to
Turning especially to
For instance, 402 may occur after flowing a volume of liquid into the tub. The liquid may include water, and may further include one or more additives as discussed above. The water may be flowed through hoses, a tube, and nozzle assembly into the tub and onto articles that are disposed in the basket for washing. The volume of liquid may be dependent upon the size of the load of articles and other variables which may, for example, be input by a user interacting with the control panel and input selectors thereof.
Optionally, 402 may occur after agitating articles within the tub (e.g., for an agitation period). During such agitation (which may be a sub-phase of the wash cycle), the volume of liquid flowed into the tub in may remain in the tub (i.e., before the volume of liquid is drained from tub). Moreover, during the agitation period, the basket may be rotated (e.g., at the tumble speed) or oscillated in alternating clockwise-counterclockwise rotation. The agitation period may be defined period of time programmed into the controller. The rotational or oscillation speed, pattern of agitation, and the agitation period may be dependent upon the size of the load of articles.
At 404, the method 400 includes rotating articles within the tub at a pre-plaster speed for a second period. Generally, the second period follows the first period (e.g., immediately or after one or more predefined periods or steps). Moreover, the second period may be a defined period of time programmed into the controller or an indeterminate period continued until a subsequent step is initiated. During the second period of 404, the basket may be rotated at the pre-plaster speed. The pre-plaster speed is greater than the tumble speed and is generally suitable to reduce the tumbling or agitation of articles within the tub, while still permitting some movement of the articles relative to, for example, the basket.
At 406, the method 400 includes measuring movement of the tub during the second period. In other words, 406 is performed simultaneously with at least a portion of the second period of 404 while articles continue to rotate at the pre-plaster speed. As described above, the measuring movement may include detecting movement of the tub as one or more displacement amplitudes or values using an accelerometer and a gyroscope. The displacement may be movement along the lateral direction (e.g., perpendicular to the axis of rotation). Additionally or alternatively, the measuring of movement may include measuring displacement at an effective center of gravity (e.g., for the tub or basket). The effective center of gravity is generally offset from a geometric center of gravity. For instance, the effective center of gravity may be offset along the Z-axis or transverse direction (e.g., parallel to the axis of rotation). The effective center of gravity may be a predetermined point calculated, for instance, from experimental data. Additionally or alternatively, the effective center may be the location (e.g., along the Z-axis) where the amplitude of PXT is approximately the same for any given out-of-balance mass located at any position along the transverse axis. Advantageously, the effective center of gravity may account for biasing forces or elements, such as the front baffle extending between the tub and the cabinet and biasing the tub along the Z-axis.
At 407, the method 400 includes determining a first out-of-balance (OOB) value (e.g., in units of weight or mass) of the tub based on a first measured movement. As described above, the OOB value may be calculated as a function of rotation velocity and, for example, measured displacement. Moreover, the function may be a predetermined transfer function. In some embodiments, a plurality of OOB values is calculated. For instance, unique OOB values may be calculated for unique displacement values measured at 406 (e.g., at different points in time during second period). Optionally, a rate of change across the plurality of values may be determined, e.g., a second OOB value may be determined at 408, and the second OOB value may be based on a second measured movement after the first measured movement. Thus, the rate of change may be determined as a relative OOB value of the tub at 410 and the relative OOB value may be based on the first OOB value and the second OOB value. Generally, multiple relative OOB values may be determined throughout the second period of 406, where each relative OOB value is based on a current OOB value and an immediately preceding OOB value.
At 411 and 412, the method 400 generally includes determining whether a first set condition and a second set condition are met based on the determined out-of-balance values. In some embodiments, the set condition includes threshold OOB values. The threshold OOB values may be set values (e.g., predetermined or programmed value), for instance, indicating an unsuitable imbalance condition. Thus, 411 may include comparing the determined relative OOB value to a first threshold OOB value and 412 may include comparing the current OOB value, e.g., second OOB value, to a second threshold. In some embodiments, if the determined relative OOB value is less than the first threshold OOB value and the determined second OOB value is less than the second threshold, the set conditions are met. The first threshold may be a threshold rate of change which may be a set value (e.g., predetermined or programmed value), for instance, indicating the balance of articles within the tub have reached a stable condition. The second threshold may be an absolute threshold, for instance, indicating that the magnitude of the movement of the tub is within acceptable limits.
If either (or both) of the set conditions is not met, the method 400 includes adjusting articles within the tub in response to the set condition not being met. For example, if the relative OOB value is not less than the first threshold at 411, the method 400 proceeds to adjust the articles at 415, and/or if the second OOB value is not less than the second threshold at 412, the method 400 proceeds to adjust the articles at 416. In some embodiments, the adjustment at 415 and/or 416 includes reducing the rotation velocity (e.g., of the basket). Optionally, the articles and basket may be returned to the pre-plaster speed (e.g., for a third period) or another reduced speed (e.g., the tumbling speed) such that articles within the tub may be permitted to move relative to, for example, the basket.
The third period generally follows the second time period (e.g., immediately or after one or more predefined periods or steps) and may be a defined period of time programmed into the controller or an indeterminate period continued until a subsequent step is initiated. Optionally, the movement may be measured during the third period (e.g., while the articles or basket rotate at the pre-plaster speed). Moreover, one or more additional OOB values may be determined from the third period measurement(s). From the additional OOB value(s), a new determination may be made if the set conditions are met. If the set conditions are both met, the method 400 may proceed to rotate the articles at a plaster speed greater than the pre-plaster speed at 414. If the set condition is not met, 415 and/or 416 may be repeated, rotation may be halted entirely, or another suitable adjustment may be made to address an imbalanced state within the tub.
At 414, the method 400 includes rotating articles within the tub at a plaster speed in response to determining the set conditions are both met (e.g., where the determinations at both 411 and 412 are YES). For instance, 414 may be performed over a fourth period that follows the second period (e.g., immediately or after one or more predefined periods or steps). The fourth period may be a defined period of time programmed into the controller or an indeterminate period continued until a subsequent step is initiated. Optionally, the fourth period and the plaster speed (e.g., rotational velocity of basket or motor assembly) during the fourth period may be dependent upon the size of the load of articles and other variables that may, for example, be input by a user interacting with the control panel and input selectors thereof. The plaster speed is greater than the pre-plaster speed and is generally suitable to plaster articles within the tub to the walls of the basket and encourage the shedding of water from the articles.
Turning now to
For instance, 502 may occur after flowing a volume of liquid into the tub. The liquid may include water, and may further include one or more additives as discussed above. The water may be flowed through hoses, a tube, and nozzle assembly into the tub and onto articles that are disposed in the basket for washing. The volume of liquid may be dependent upon the size of the load of articles and other variables which may, for example, be input by a user interacting with the control panel and input selectors thereof.
Optionally, 502 may occur after agitating articles within the tub (e.g., for an agitation period). During such agitation (which may be a sub-phase of the wash cycle), the volume of liquid flowed into the tub in may remain in the tub (i.e., before the volume of liquid is drained from tub). Moreover, during the agitation period, the basket may be rotated (e.g., at the tumble speed) or oscillated in alternating clockwise-counterclockwise rotation. The agitation period may be defined period of time programmed into the controller. The rotational or oscillation speed, pattern of agitation, and the agitation period may be dependent upon the size of the load of articles.
At 504, the method 500 includes rotating articles within the tub at a pre-plaster speed for a second period. Generally, the second period follows the first period (e.g., immediately or after one or more predefined periods or steps). Moreover, the second period may be a defined period of time programmed into the controller or an indeterminate period continued until a subsequent step is initiated. During the second period of 504, the basket may be rotated at the pre-plaster speed. The pre-plaster speed is greater than the tumble speed and is generally suitable to reduce the tumbling or agitation of articles within the tub, while still permitting some movement relative to, for example, the basket.
At 506, the method 500 includes measuring movement of the tub along the lateral direction (e.g., perpendicular to the axis of rotation) during the second period. In other words, 506 is performed simultaneously with at least a portion of the second period of 504 while articles continue to rotate at the pre-plaster speed. As described above, the measuring movement may include detecting movement of the tub as one or more displacement amplitudes or values using the accelerometer and a gyroscope. The displacement may be movement along the lateral direction (e.g., perpendicular to the axis of rotation). Additionally or alternatively, the measuring of movement may include measuring displacement at an effective center of gravity (e.g., for the tub or basket). The effective center of gravity is generally offset from a geometric center of gravity. For instance, the effective center of gravity may be offset along the Z-axis or transverse direction (e.g., parallel to the axis of rotation). The effective center of gravity may be a predetermined point calculated, for instance, from experimental data. Additionally or alternatively, the effective center may be the location (e.g., along the Z-axis) where the amplitude of PXT is approximately the same for any given out-of-balance mass located at any position along the transverse axis. Advantageously, the effective center of gravity may account for biasing elements, such as the front baffle extending between the tub and the cabinet.
The method 500 may include determining a plurality of out-of-balance (OOB) values of the tub based on the measured movement, as described above. For example, the OOB value may be calculated as a function of rotation velocity and, for example, measured displacement.
Using the plurality of OOB values, e.g., based on chronologically consecutive OOB values such as a current out-of-balance value and a previous out-of-balance value of the plurality of out-of-balance values, a relative OOB value of the tub may be determined at 510.
At 511 and 512, the method 500 generally includes determining whether a first set condition and a second set condition are met based on the measured movement. For instance, the set conditions may include threshold displacement values. In other words, the set conditions may require that the measured lateral displacement be less than the threshold displacement value. In additional or alternative embodiments, the set conditions include threshold OOB values. As described above, the threshold OOB values may be a set value (e.g., predetermined or programmed value), for instance, indicating an unsuitable imbalance condition.
Thus, 511 may include comparing the determined relative OOB value to a first threshold OOB value and 512 may include comparing the current OOB value to a second threshold OOB value. For example, the first threshold OOB value may be a relative or rate of change OOB value and the second threshold OOB value may be an absolute magnitude value. In some embodiments, the first threshold OOB value includes a threshold rate of change across the plurality of determined OOB values, e.g., from the previous (immediately preceding) OOB value to the current OOB value. The threshold rate of change may be a set value (e.g., predetermined or programmed value), for instance, indicating the balance of articles within the tub have reached a stable condition. Thus, 511 may include comparing the determined rate of change to the threshold rate of change. If the determined relative OOB value is less than the first threshold OOB value and the determined current OOB value is less than the second threshold OOB value, the set conditions may be met.
At 515 and 516, the method 500 includes adjusting articles within the tub in response to either or both of the set conditions not being met. In some embodiments, the adjustment at 515 or 516 includes reducing the rotation velocity (e.g., of the basket). Optionally, the articles and basket may be returned to the pre-plaster speed (e.g., for a third period) or another reduced speed (e.g., the tumbling speed) such that articles within the tub may be permitted to move relative to, for example, the basket.
The third period generally follows the second time period (e.g., immediately or after one or more predefined periods or steps) and may be a defined period of time programmed into the controller or an indeterminate period continued until a subsequent step is initiated. Optionally, the movement may be measured during the third period (e.g., while the articles or basket rotate at the pre-plaster speed). Moreover, one or more additional OOB values may be determined from the third period measurement(s). From the additional OOB value(s), a new determination may be made if the set condition is met. If the set condition is met, the method 500 may proceed to 514. If either the set condition is not met at 511 or 512, 515 or 516 may be repeated, rotation may be halted entirely, or another suitable adjustment may be made to address an imbalanced state within the tub.
At 514, the method 500 includes rotating articles within the tub at a plaster speed in response to determining the set condition is met (e.g., where the relative out-of-balance value is less than the first threshold at 511 and the current out-of-balance value is less than the second threshold at 512). For instance, 514 may be performed over a fourth period that follows the second period (e.g., immediately or after one or more predefined periods or steps). The fourth period may be a defined period of time programmed into the controller or an indeterminate period continued until a subsequent step is initiated. Optionally, the fourth period and the plaster speed (e.g., rotational velocity of basket or motor assembly) during the fourth period may be dependent upon the size of the load of articles and other variables that may, for example, be input by a user interacting with the control panel and input selectors thereof. The plaster speed is greater than the pre-plaster speed and is generally suitable to plaster articles within the tub to the walls of the basket and encourage the shedding of water from the articles.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
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