WASHING MACHINE AND CONTROL METHOD THEREOF

Abstract

A washing machine that can determine a weight of laundry in consideration of the result of determination on whether the laundry is dry cloth or wet cloth, and a control method of the washing machine. Before washing starts, a drum rotates to measure a changed amount in water level, and it is determined whether laundry is dry cloth or wet cloth based on the changed amount in water level. If it is determined that the laundry is wet cloth, a weight of the laundry is accurately detected by using wet cloth weight criteria or by adding a weight according to the changed amount in water level, which leads to reducing water consumption, a washing time, and energy consumption while preventing laundry from being damaged.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 10-2013-0127648, filed on Oct. 25, 2013 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

1. Field

Embodiments of the present disclosure relate to a washing machine of determining a weight of laundry in consideration of the result of determination on whether the laundry is dry cloth or wet cloth, and a control method of the washing machine.

2. Description of the Related Art

In general, a washing machine (e.g., a full automatic washing machine) includes a tub to load water (washing water or rinsing water), a drum rotatably installed inside the tub to accommodate laundry, a pulsator rotatably installed inside the drum to generate streams of water, and a motor to generate a driving force for rotating the drum and the pulsator. The washing machine removes contaminants from laundry through surface action between streams of water and detergents.

The washing machine washes laundry through a series of operations: a washing process of removing contaminants from the laundry with water (in detail, washing water) in which detergents have been dissolved; a rinsing process of rinsing the laundry with water (rinse water) including no detergents to remove remaining bubbles or detergents from the laundry; and a dehydrating process of removing water from the laundry by centrifugal force.

When washing is done through the series of operations described above, the motor is driven at predetermined Revolution Per Minute (RPM) and a predetermined driving rate during each of the washing process, the rinsing process, and the dehydrating process. The RPM and driving rate of the motor for each process is set depending on the weight (load) of the laundry.

Accordingly, there is a need for accurately determining a weight of laundry in order to control driving of a motor according to the load of the laundry and to determine an amount of water and a time that are consumed for washing and rinsing processes.

Conventional washing machines determine a weight of laundry before starting washing. The weight of laundry is determined by calculating an acceleration time taken for the velocity of a drum in which the laundry is loaded to reach a predetermined velocity when applying predetermined torque (or, a predetermined voltage) after accelerating the velocity of the drum to a predetermined velocity.

However, when the laundry is wet cloth, the weight of the laundry may be wrongly determined as a load more than the actual amount of the laundry. In this case, a greater amount of water, a longer time, and higher energy will be used for washing and rising processes than those required for the actual amount of the laundry, which may lead to damaging the laundry and wasting water.

SUMMARY

Therefore, it is an aspect of the present disclosure to provide a washing machine that accurately determines a weight of laundry by determining whether the laundry is wet cloth or dry cloth and applying different weight criterion according to the result of the determination, and a control method of the washing machine.

Additional aspects of the disclosure will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the disclosure.

In accordance with one aspect of the present disclosure, a control method of a washing machine, the washing machine including a tub to accommodate water therein, and a drum rotatably installed in the tub and configured to accommodate laundry therein, the control method includes: determining whether the washing machine starts operating; rotating, if it is determined that the washing machine starts operating, the drum before supplying water to the tub; measuring a changed amount in water level according to the rotation of the drum to determine whether the laundry is dry cloth or wet cloth; and setting, if it is determined that the laundry is wet cloth, a washing condition corresponding to wet cloth.

The control method may further include a washing motor configured to rotate the drum, wherein the rotating of the drum includes rotating the washing motor at Revolution Per Minute (RPM) for dehydrating water contained in the laundry.

The RPM may be equal to or more than 90 RPM.

The control method may further include a water level sensor configured to measure a level of water loaded in the tub, wherein the determining of whether the laundry is dry cloth or wet cloth includes: measuring a level of water loaded in the tub using the water level sensor before rotating the drum; measuring a level of water loaded in the tub using the water level sensor after rotating the drum; and measuring a changed amount in water level by comparing the level of water measured before rotating the drum to the level of water measured after rotating the drum to determine whether the laundry is dry cloth or wet cloth.

The control method may further include determining, if a changed amount in water level is measured, that the laundry is wet cloth.

The control method may further include determining, if no changed amount in water level is measured, that the laundry is dry cloth.

The setting of the washing condition corresponding to wet cloth may include determining a weight of the laundry using weight criteria that is different from weight criteria to be used when the laundry is dry cloth.

The control method may further include a washing motor configured to rotate the drum, wherein the determining of the weight of the laundry may include estimating a weight of the laundry using an acceleration time taken for the drum to reach a predetermined velocity when predetermined torque is applied to the washing motor.

The determining of the weight of the laundry may include performing, if it is determined that the laundry is wet cloth, a wetting process to wet the laundry, and then estimating a weight of the laundry.

The determining of whether the laundry is dry cloth or wet cloth may be performed before a water supply process of initially supplying water in order to wash the laundry.

The determining of whether the laundry is dry cloth or wet cloth may be performed before determining the weight of the laundry.

In accordance with another aspect of the present disclosure, a washing machine includes: a tub configured to accommodate water therein; a drum rotatably installed in the tub and configured to accommodate laundry therein; a washing motor configured to rotate the drum; and a controller configured to control the washing motor to rotate the drum before supplying water to the tub, to measure a changed amount in water level according to the rotation of the drum, and to set a washing condition according to the changed amount in water level.

The controller may rotate the drum at Revolution Per Minute (RPM) for dehydrating water contained in the laundry.

The washing machine may further include a water level sensor configured to measure a level of water loaded in the tub, wherein the controller may measure a level of water loaded in the tub using the water level sensor before rotating the drum, measure a level of water loaded in the tub using the water level sensor after rotating the drum, and measure a changed amount in water level by comparing the level of water measured before rotating the drum to the level of water measured after rotating the drum to determine whether the laundry is dry cloth or wet cloth.

If a changed amount in water level is measured, the controller may determine that the laundry is wet cloth.

The controller may determine a weight of the laundry using an acceleration time taken for the washing motor to reach a predetermined velocity when predetermined torque is applied to the washing motor.

If it is determined that the laundry is wet cloth, the controller may perform a wetting process to wet the laundry before determining a weight of the laundry.

The controller may determine whether the laundry is dry cloth or wet cloth according to the changed amount in water level, and determine a weight of the laundry using different weight criterion depending on whether the laundry is dry cloth or wet cloth.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects of the disclosure will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a cross-sectional view illustrating a configuration of a washing machine according to an embodiment of the present disclosure;

FIG. 2 is a block diagram illustrating a control configuration of a washing machine according to an embodiment of the present disclosure;

FIG. 3 is a flowchart illustrating a control method of a washing machine, according to an embodiment of the present disclosure; and

FIG. 4 is a cross-sectional view illustrating a configuration of a washing machine according to another embodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

FIG. 1 is a cross-sectional view illustrating a configuration of a washing machine according to an embodiment of the present disclosure.

Referring to FIG. 1, a washing machine 1 may include a cabinet 10 having a box shape and constituting an external appearance of the washing machine 1, a tub 11 installed inside the cabinet 10 and configured to load water (washing water or rinsing water) therein, a drum 12 rotatably installed inside the tub 11 and configured to load laundry therein, a pulsator 13 rotatably installed inside the drum 12 and configured to rotate in a left or right direction (forwardly or backwardly) to generate streams of water, and a washing shaft 17 which is perpendicular to the ground.

The drum 12 has a cylindrical shape wherein the top part opens, and a plurality of through-holes 12a are formed around the drum 12. A balancer 12b may be provided in the upper part of the drum 12 so that the drum 12 can stably rotate upon high-speed rotation.

Below the tub 11, a washing motor 14 to generate a driving force for rotating the drum 12 and the pulsator 13, and a power switching device 15 to transfer the driving force generated by the washing motor 14 to both or one of the drum 12 and the pulsator 13 may be provided.

The drum 12 may be connected to a hollow dehydrating shaft 16, and the washing shaft 17 installed in the cavity of the dehydrating shaft 16 may be connected to the pulsator 13 through a washing shaft connecting element 18.

The washing motor 14 may be a Direct Drive (DD) type motor having a variable speed function. The washing motor 14 may transfer a driving force to the drum 12 or the pulsator 13 according to an upward/downward movement of the power switching device 15.

The washing motor 14 may be a universal motor composed of a field coil and an armature, or a Brush Less Direct Current (BLDC) motor composed of a stator and a rotor. However, the washing motor 14 may be any other motor as long as it can be applied to the washing machine 1. Also, the washing motor 14 may be a belt type.

The power switching device 15 may include an actuator 15a to generate a driving force for switching power, a rod element 15b to move linearly according to an operation of the actuator 15a, and a clutch element 15c connected to the rod element 15b and configured to rotate according to a movement of the rod element 15b.

The washing motor 14 may perform wetting cloth, dissolving detergents, washing, dipping and rising, and untangling cloth by rotating the washing shaft 17 forward or backward when coupling between the washing shaft 17 and the dehydrating shaft 16 is released to thus move the pulsator 13 in left and right directions.

Also, the washing motor 14 may rotate the washing shaft 17 and the dehydrating shaft 16 in a forward or backward direction when the washing shaft 17 is coupled with the dehydrating shaft 16 so as to rotate both the pulsator 13 and the drum 12 in the same direction, thereby performing a shower-rinsing process and a dehydrating process.

A water level sensor 19 for detecting a frequency changing according to a level of water to determine an amount (level) of water loaded in the tub 11 may be installed on the lower inner surface of the tub 11.

A drain 20 to discharge water loaded in the tub 11 to the outside may be formed in the bottom of the tub 11, and the drain 20 may be connected to a first drainpipe 21. A drain motor 22 to control drainage may be installed in the first drainpipe 21, and an outlet of the drain motor 22 may be connected to a second drainpipe 23 to discharge water to the outside.

In the upper part of the cabinet 10, a door 25 for opening or closing the washing machine 1 in order to put laundry into the drum 12 or to take laundry out of the drum 12 may be mounted.

In the upper part of the tub 11, an opening 27 to put laundry into the drum 12 or to take laundry out of the drum 12 may be formed, and the opening 27 may be opened or closed by the door 25.

Also, a water-supply pipe 40 to supply water to the tub 11 may be installed in the upper part of the cabinet 10. One end of the water-supply pipe 40 may be connected to an external water-supply source, and the other end of the water-supply pipe 40 may be connected to a detergent supply unit 41. Water supplied through the water-supply pipe 40 may be supplied to the tub 11 together with a detergent via the detergent supply unit 41. The water-supply pipe 40 may include a water-supply valve 42 to control supply of water.

Meanwhile, the tub 11 may be supported by a suspension system 43 with respect to the cabinet 10, and a checker switch 44 to detect shaking that occurs when a user touches the drum 12 in order to take laundry out of the drum 12 may be installed between the tub 11 and the cabinet 10. In addition, when the drum 12 rotates eccentrically due to an unbalanced load of laundry, the checker switch 44 may detect excessive vibration of the tub 11 when the tub 11 hits the checker switch 44 before hitting the cabinet 10.

FIG. 2 is a block diagram illustrating a control configuration of a washing machine according to an embodiment of the present disclosure. Referring to FIG. 2, a washing machine 1 may include an input unit 50, a controller 52, a memory 54, a driver 56, and a display unit 58.

The input unit 50 allows a user to input a command for performing a washing process, a rinsing process, and a dehydrating process of the washing machine 1. The input unit 50 may be configured with keys, buttons, switches, and a touch pad, and may include all devices capable of generating predetermined input data through a manipulation, such as pressing, contacting, pressure, and rotating.

Also, the input unit 50 may include a plurality of buttons (a power button, a reservation button, a button for setting temperature of wash water, a soak function button, a washing button, a dehydrating button, a water level selection button, etc.) allowing a user to input a command related to an operation of the washing machine 1. The buttons may include operation buttons 51 allowing the user to input a start command or a pause command.

The controller 52 may be a micom for controlling overall operations of the washing machine 1, such as washing, rinsing, and dehydrating, according to driving information received from the input unit 50. The controller 52 may set goal levels of water (a level of washing water and a level of rinsing water), goal RPMs, a motor driving rate (on and off times of the washing motor 14 (see FIG. 1)), a washing time, and a rinsing time, according to a weight (a load) of laundry determined in a washing course.

Also, the controller 52 may determine whether laundry is dry cloth or wet cloth, before a weight (a load) of the laundry is determined after the laundry is put into the drum 12 (see FIG. 1). In order to determine whether laundry is dry cloth or wet cloth, when laundry is put into the drum 12, a current level of water loaded in the tub 11 may be measured using the water level sensor 19 before washing starts. Thereafter, the drum 12 may rotate at first RPM (about 90 RPM to 250 RPM for dehydrating water contained in the laundry) for a predetermined time period (about 1 to 2 minutes) to dehydrate water contained in the laundry. Then, a level of water may be again measured using the water level sensor 19.

If the laundry is dry cloth, since no water is discharged from the laundry although the drum 12 rotates at the first RPM for the predetermined time period, there will be no difference between the level of water measured before the drum 12 rotates and the level of water measured after the drum 12 rotates.

However, if the laundry is wet cloth, since water contained in the laundry is discharged when the drum 12 rotates at the first RPM for the predetermined time period, there will be a difference between the level of water measured before the drum 12 rotates and the level of water measured after the drum 12 rotates.

Accordingly, the controller 52 may compare the level of water measured before the drum 12 rotates to the level of water measured after the drum 12 rotates. If the controller 52 determines that there is no difference between the measured levels of water, the controller 52 determines that the laundry is dry cloth, and if the controller 52 determines that there is a difference between the measured levels of water, the controller 52 may determine that the laundry is wet cloth.

In other words, if the controller 52 determines that the level of water measured after the drum 12 rotates is higher than the level of water measured before the drum 12 rotates (that is, if the controller 52 determines that water has been added), the controller 52 may determine that the laundry loaded in the drum 12 is wet cloth.

Also, the controller 52 may apply different weight tables according to the result of the determination on whether the laundry is dry cloth or wet cloth, so as to determine a weight of the laundry.

For example, when the controller 52 determines that the laundry is dry cloth, the controller 52 may determine a weight of the laundry by calculating an acceleration time taken for the velocity of the drum 12 to reach a predetermined velocity when applying predetermined torque (or, a predetermined voltage) after accelerating the velocity of the drum 12 to a predetermined velocity. Since the acceleration time is proportional to the weight of the laundry, the controller 52 may estimate a weight of the laundry using a dry cloth weight table corresponding to the acceleration time.

Meanwhile, when the controller 52 determines that the laundry is wet cloth, the controller 52 may determine a weight of the laundry by calculating an acceleration time taken for the velocity of the drum 12 to reach a predetermined velocity when applying predetermined torque (or, a predetermined voltage) after accelerating the velocity of the drum 12 to a predetermined velocity. Likewise, since the acceleration time is proportional to the weight of the laundry, the controller 52 may estimate a weight of the laundry using a wet cloth weight table corresponding to the acceleration time.

However, when the laundry is wet cloth, a level of water measured after the drum 12 rotates may depend on a wet degree of the laundry. Accordingly, it is difficult to accurately estimate a weight of wet cloth using one wet cloth weight table.

For example, a level of water measured after the drum 12 rotates varies according to various conditions of wet cloth, such as a case in which laundry is fully wet, a case in which laundry is damp although it is not fully wet, and a case in which a part of laundry is wet cloth and the remaining part of the laundry is dry cloth.

Accordingly, in order to accurately estimate a weight of laundry regardless of a wet condition of the laundry, when the controller 52 determines that laundry is wet cloth, the controller 52 may equalize a wet condition of the laundry before determining a weight of the laundry using the wet cloth weight table.

In order to equalize a wet condition of laundry, a wetting process or a vessel cleansing process can be used.

When a wetting process is used to equalize a wet condition of laundry, water is supplied to the tub 11 until the water reaches a wetting level, the washing motor 14 rotates in left and right directions to fully wet the laundry, and then, the drum 12 rotates to dehydrate the laundry.

Alternatively, the controller 52 may determine a weight of the laundry after adding a weight to the wet cloth weight table according to a changed amount in water level.

The memory 54 may store control data for controlling operations of the washing machine 1, reference data that is used to control operations of the washing machine 1, operation data that is generated while the washing machine 1 performs a predetermined operation, setting information such as setting data input by the input unit 90 in order for the washing machine 1 to perform a predetermined operation, the number of times the washing machine 1 has performed a predetermined operation, and model information of the washing machine 1. When the washing machine 1 operates wrongly, the memory 54 may further store fault information, such as information about a cause of the wrong operation and information about a location at which the wrong operation has occurred.

The driver 56 may drive the washing motor 14, the drain motor 22, and the water-supply valve 42 related to an operation of the washing machine 1, according to a driving control signal of the controller 52.

The display unit 58 may display an operation state of the washing machine 1 and a manipulation state of the user, according to a display control signal of the controller 52.

Hereinafter, a control method of the washing machine 1, according to an embodiment of the present disclosure, will be described with reference to FIGS. 2 and 3.

FIG. 3 is a flowchart illustrating a control method of a washing machine, according to an embodiment of the present disclosure. The control method relates to an algorithm for determining a weight of laundry in consideration of the result of determination on whether the laundry is dry cloth or wet cloth.

Referring to FIGS. 2 and 3, if a user selects a wash course (a standard course, a wool course, or a delicate course) according to a kind of laundry, and inputs driving information related to an operation of the washing machine 1 after the user puts the laundry in the drum 12, information about the selected course and the driving information may be transferred to the controller 52 through the input unit 50. Then, the user may manipulate one of the operation buttons 51 to input an operation start command to the washing machine 1.

Then, the controller 52 may determine whether the washing machine 1 starts operating (operation 100), and if the controller 52 determines that the washing machine 1 starts operating, the controller 52 may measure a current level W1 of water loaded in the tub 11 using the water level sensor 19 before starting washing (operation 102).

Then, the controller 52 may store the measured level W1 of water loaded in the tub 11 in the memory 54.

Successively, the controller 52 may drive the washing motor 15 through the driver 56 to rotate the drum 12 at first RPM (about 90 RPM to 150 RPM for dehydrating water contained in laundry) (operation 104).

The first RPM is RPM at which laundry starts being pushed against the inner wall of the tub 11. The first RPM may be set to any RPM higher than about 90 RPM. That is, the first RPM may be set to RPM capable of dehydrating water contained in laundry.

The controller 52 may count a time for which the drum 12 rotates at the first RPM, and determine whether a first time period (about 1 to 2 minutes for which water contained in laundry can be dehydrated) has elapsed (operation 106).

If the controller 52 determines that the first time period has not elapsed, the controller 52 may return to operation 104 to continue to rotate the drum 12 until the first time period has elapsed. If the drum 12 continues to rotate in the same direction, the laundry is pushed against the drum 12 so that the laundry is dehydrated and water is collected in the tub 11.

Meanwhile, if the controller 52 determines that the first time period has elapsed, the controller 52 may stop operating the washing motor 14 through the driver 56, and then measure a level W2 of water collected in the tub 11 after the drum 12 rotates, using the water level sensor 19 (operation 108).

Thereafter, the controller 52 may compare the level W1 of water measured before the drum 12 rotates to the level W2 of water measured after the drum 12 rotates, and determine whether there is a difference between the level W1 of water and the level W2 of water (operation 110).

If the controller 52 determines whether there is a difference between the level W1 of water and the level W2 of water, the controller 52 may determine that the laundry put into the drum 12 is wet cloth, and determine a weight of the laundry using a wet cloth weight table.

When the controller 52 determines that the laundry is wet cloth, the controller 52 may execute a wetting algorithm in order to equalize a wet condition of the laundry since a level of water measured after the drum 12 rotates depends on a wet degree of the laundry.

In order to execute the wetting algorithm, the controller 52 may operate the water-supply valve 42 through the driver 56 to supply water (washing water) required for a wetting process.

If the water supply valve 42 operates, the water supply valve 42 opens so that water (wash water) supplied through an external water supply pipe is supplied to the tub 11 through the water supply pipe 40 (operation 112).

The controller 52 may measure a level of water supplied to the tub 11 through the water level sensor 19, and supply water to the tub 11 until a level of water supplied to the tub 11 reaches a wetting level (a level of water at which the laundry can be fully wet).

An amount of water that is consumed until a level of water loaded in the tub 11 reaches the wetting level has been given in advance by an experiment. For example, an amount of water that is consumed until a level of water loaded in the tub 11 reaches the wetting level when water is supplied to the tub 11 after laundry is put into the drum 12 can be measured. The wetting level may be set to a low level of water such that laundry of a predetermined volume can be wetted regardless of an amount of laundry put into the drum 12.

Generally, the washing machine 1 divides water level frequencies that can be detected by the water level sensor 19 into a plurality of water level frequency bands, and controls supply of water until a water level frequency detected by the water level sensor 19 reaches a goal water level frequency band. Accordingly, the wetting level may be set to a value corresponding to a minimum level of water among levels of water when water is supplied in correspondence to the water level frequency bands.

If a level of water supplied to the tub 11 reaches the wetting level, the controller 52 may stop operating the water supply valve 42 to stop supplying water.

Thereafter, the controller 52 may rotate the washing motor 14 in left and right directions for a second time period (about 1 to 3 minutes for which the laundry can be wetted) through the driver 56, thereby performing a wetting process (operation 114).

In detail, after water is supplied to the drum 12 until a level of water reaches the wetting level, the pulsator 13 is connected to the washing shaft 17 of the washing motor 14 to drive the washing motor 14 at second RPM (about 40 RPM to 50 RPM at which the laundry can be wetted), thereby rotating the pulsator 13 in left and right directions.

If the pulsator 13 rotates in the left and right directions by left- and right-directional rotations of the washing motor 14, the laundry loaded in the drum 12 is wetted with water.

The second RPM is RPM at which laundry can be wetted by generating water streams for transferring water to the laundry. The second RPM may be set to any RPM higher than about 40 RPM. That is, the second RPM may be set to RPM capable of wetting laundry.

The controller 52 may count a time for which the drum 12 rotates at the second RPM, and perform a wetting process for a second time period (about 1 to 3 minutes).

If the wetting process terminates, the controller 52 may determine that the laundry has been fully wetted, and perform dehydrating (operation 116).

As such, when the controller 52 determines that the laundry put into the drum 12 is wet cloth, the controller 52 may equalize a wet condition of the laundry by performing a series of processes of supplying water and dehydrating by rotating the washing motor 14 in left and right directions.

After the controller 52 equalizes the wet condition of the laundry, the controller 52 may determine a weight (a load) of the laundry put into the drum 12 using the wet cloth weight table (operation 118).

Alternatively, the controller 52 may determine a weight (a load) of the laundry put into the drum 12 after adding a weight to the wet cloth weight table according to a changed amount in water level.

The controller 52 may determine a weight of the laundry by calculating an acceleration time taken for the velocity of the drum 12 to reach a predetermined velocity when applying predetermined torque (or, a predetermined voltage) after accelerating the velocity of the drum 12 to a predetermined velocity. Since the acceleration time is proportional to the weight of the laundry, the controller 52 may estimate a weight of the laundry using a wet cloth weight table corresponding to the acceleration time.

The controller 52 may determine a weight of the laundry using a method selected from among: a method of determining a weight of laundry by applying a predetermined duty of about 90V to the washing motor 14 while rotating the washing motor 14 at predetermined RPM between 70 RPM and 150 RPM for detecting a weight of laundry, and calculating a time taken for the washing motor 14 to reach a predetermined duty and an angular velocity when the washing motor 14 reaches the predetermined duty; a method of determining a weight of laundry by calculating a time taken for the washing motor 14 to reach a predetermined velocity (or predetermined RPM) using instantaneous acceleration of the washing motor 14; and a method of determining a weight of laundry using Newton's second law of motion (torque=the moment of inertia x acceleration) after directly or indirectly measuring a moment of inertia of the drum 12 by applying torque to the washing motor 14 for a predetermined time period, as disclosed in Japanese Patent Applications Nos. 2002-336593, 2004-267334, and 07-90077.

Meanwhile, if the controller 52 determines whether there is no difference between the level W1 of water and the level W2 of water in operation 110, the controller 52 may determine that the laundry put into the wash tub 12 is dry cloth, and the controller 52 may determine a weight of the laundry using a dry cloth weight table (operation 120).

At this time, the controller 52 may determine a weight of the laundry using the same method of determining a weight of laundry, as described above, although using a different weight table corresponding to an acceleration time.

As such, by determining a weight of laundry using different weight tables depending on whether laundry is dry cloth or wet cloth, the weight of the laundry can be accurately determined.

If the weight (load) of the laundry is determined, the controller 52 may set RPM and a driving rate (on-off times) of the wash water 14, goal levels of water (a goal level of washing water and a goal level of rinsing water), a washing time, and a rinsing time, according to the determined weight (load) of the laundry (operation 122).

Setting goal RPM and a driving rate (on-off times) of the wash water 14, a goal level of washing water, a goal level of rinsing water, a washing time, and a rinsing time, according to a weight (load) of laundry may be performed when a user inputs no command regarding an operation of the washing machine 1. If a user inputs a command regarding an operation of the washing machine 1, the goal RPM and the driving rate (on-off times) of the wash water 14, the goal level of washing water, the goal level of rinsing water, the washing time, and the rinsing time, set according to the weight (load) of the laundry may be changed according to the command from the user.

Successively, the controller 52 may perform the following processes (specifically, a washing process, a rinsing process, and a dehydrating process) of the washing machine 1 using the goal RPM and the driving rate (on-off times) of the wash water 14, the goal level of washing water, the goal level of rinsing water, the washing time, and the rinsing time, set according to the weight (load) of the laundry (operation 124).

Meanwhile, the above-described embodiment relates to a case in which a method of determining a weight of laundry in consideration of the result of determination on whether the laundry is dry cloth or wet cloth is applied to a full automatic washing machine such as the washing machine 1, however, the present disclosure can be applied to a drum washing machine 301 as illustrated in FIG. 4 so that the same purposes and effects as in the above-described embodiment can be achieved.

FIG. 4 is a cross-sectional view illustrating a configuration of a washing machine according to another embodiment of the present disclosure.

Referring to FIG. 4, a washing machine 1001 may include a main body 1010 having a box shape and constituting an external appearance of the washing machine 1001, a tub 1020 installed inside the main body 1010, a drum 1030 rotatably installed inside the tub 1020, and a motor 1040 configured to drive the drum 1030.

In the front part of the main body 1010, an opening 1011 to put laundry into the drum 1030 may be formed, and the opening 1011 may be opened or closed by a door 1012 installed on the front part of the main body 1010.

The drum 1030 may include a cylindrical portion 1031, a front plate 1032 formed in the front side of the cylindrical portion 1030, and a rear plate 1033 formed in the rear side of the cylindrical part 1030. A hole 1032a for putting laundry into the drum 1030 or taking laundry out of the drum 1030 may be formed in the front plate 1032, and a driving shaft 1043 for transferring power from a motor 1040 may be connected to the rear plate 1033.

A plurality of through-holes 1034 through which wash water passes may be formed around the drum 1030, and a plurality of lifters 1035 may be formed in the inner peripheral surface of the drum 1030 so that laundry rises and falls down when the drum 1030 rotates.

The motor 1040 may include a stator 1041 fixed onto the rear part of the tub 1020, a rotor 1042 rotating while interacting with the stator 1041, and a driving shaft 1043 wherein one end is fixed on the center of the rotator 1042, and the other end penetrates the tub 1020 and is fixed on the center of the rear plate 1033 of the drum 1030.

The driving shaft 1043 may be disposed between the drum 1030 and the motor 1040. One end of the driving shaft 1043 may be connected to the rear plate 1033 of the drum 1030, and the other end of the driving shaft 1043 may extend out of the rear wall of the tub 1020. If the motor 1040 drives the driving shaft 1043, the drum 1030 connected to the driving shaft 1043 may rotate with respect to the driving shaft 1043.

A bearing housing 1021 to rotatably support the driving shaft 1043 may be installed in the rear wall of the tub 1020. The bearing housing 1021 may be made of an aluminum alloy, and inserted into the rear wall of the tub 1020 when the tub 1020 is injection molded. Bearings 1022 may be installed between the bearing housing 1021 and the driving shaft 1043 in order to smoothly rotate the driving shaft 1043.

The tub 1020 may be supported by a damper 1023. The damper 1023 may connect the outer surface of the tub 1020 to the inner, lower surface of the main body 1010.

Above the tub 1020, a water supply unit 1050 to supply water to the tub 1020, and a detergent supply unit 1070 connected to the water supply unit 1050 and configured to supply water supplied through the water supply unit 1050 to the tub 1020 together with a detergent may be provided. Below the tub 1020, a drain unit 1060 to discharge water loaded in the tub 1020 out of the main body 1010 may be provided.

The water supply unit 1050 may include water supply pipes 1051 connecting an external water supply source (not shown) to the detergent supply unit 1070 in order to supply water (wash water or rinse water) to the tub 1020, water-supply valves 1052 installed in the water supply pipes 1051 and configured to control supply of water, and a connection pipe 1053 connecting the detergent supply unit 1070 to the tub 1020.

The drain unit 1060 may include a drainpipe 1061 to discharge water loaded in the tub 1020 to the outside, and a drain pump 1062 installed in the drainpipe 1061 and configured to discharge water through the drainpipe 1061.

The detergent supply unit 1070 may be connected to the tub 1020 through the connection pipe 1053 connected to the lower part of the detergent supply unit 1070. Water supplied through the water supply pipes 1051 may pass through the detergent supply unit 1070 and be supplied to the tub 1020 through the connection pipe 1053. This structure is aiming at causing water to be supplied to the tub 1020 via the detergent supply unit 1070 so that a detergent contained in the detergent supply unit 1070 can be supplied to the tub 1020 together with water. The washing machine 1001 may also include sensors 1080, 1082 and 1084.

According to the washing machine and the control method thereof as described above, before washing starts, the drum rotates to measure a changed amount in water level, and it is determined whether laundry is dry cloth or wet cloth based on the changed amount in water level. If the laundry is wet cloth, a weight of the laundry is accurately detected by using weight criteria corresponding to wet cloth, which leads to reducing water consumption, a washing time, and energy consumption while preventing laundry from being damaged.

Although a few embodiments of the present disclosure have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Claims

1. A control method of a washing machine, the washing machine including a tub to accommodate water therein, and a drum rotatably installed in the tub and configured to accommodate laundry therein, the control method comprising:

determining whether the washing machine starts operating;

rotating, if it is determined that the washing machine starts operating, the drum before supplying water to the tub;

measuring a changed amount in water level according to the rotation of the drum to determine whether the laundry is dry cloth or wet cloth; and

setting, if it is determined that the laundry is wet cloth, a washing condition corresponding to wet cloth.

2. The control method according to claim 1, further comprising a washing motor configured to rotate the drum, wherein the rotating of the drum comprises rotating the washing motor at Revolution Per Minute (RPM) for dehydrating water contained in the laundry.

3. The control method according to claim 2, wherein the RPM is equal to or more than 90 RPM.

4. The control method according to claim 1, further comprising a water level sensor configured to measure a level of water loaded in the tub,

wherein the determining of whether the laundry is dry cloth or wet cloth comprises:

measuring a level of water loaded in the tub using the water level sensor before rotating the drum;

measuring a level of water loaded in the tub using the water level sensor after rotating the drum; and

measuring a changed amount in water level by comparing the level of water measured before rotating the drum to the level of water measured after rotating the drum to determine whether the laundry is dry cloth or wet cloth.

5. The control method according to claim 4, further comprising determining, if a changed amount in water level is measured, that the laundry is wet cloth.

6. The control method according to claim 4, further comprising determining, if no changed amount in water level is measured, that the laundry is dry cloth.

7. The control method according to claim 1, wherein the setting of the washing condition corresponding to wet cloth comprises determining a weight of the laundry using weight criteria that is different from weight criteria to be used when the laundry is dry cloth.

8. The control method according to claim 7, wherein the washing machine further includes a washing motor configured to rotate the drum, and

wherein the determining of the weight of the laundry comprises estimating a weight of the laundry using an acceleration time taken for the drum to reach a predetermined velocity when predetermined torque is applied to the washing motor.

9. The control method according to claim 7, wherein the determining of the weight of the laundry comprises performing, if it is determined that the laundry is wet cloth, a wetting process to wet the laundry, and then estimating a weight of the laundry.

10. The control method according to claim 4, wherein the determining of whether the laundry is dry cloth or wet cloth is performed before a water supply process of initially supplying water in order to wash the laundry.

11. The control method according to claim 4, wherein the determining of whether the laundry is dry cloth or wet cloth is performed before determining the weight of the laundry.

12. A washing machine comprising:

a tub configured to accommodate water therein;

a drum rotatably installed in the tub and configured to accommodate laundry therein;

a washing motor configured to rotate the drum; and

a controller configured to control the washing motor to rotate the drum before supplying water to the tub, to measure a changed amount in water level according to the rotation of the drum, and to set a washing condition according to the changed amount in water level.

13. The washing machine according to claim 12, wherein the controller rotates the drum at Revolution Per Minute (RPM) for dehydrating water contained in the laundry.

14. The washing machine according to claim 12, further comprising a water level sensor configured to measure a level of water loaded in the tub,

wherein the controller measures a level of water loaded in the tub using the water level sensor before rotating the drum, measures a level of water loaded in the tub using the water level sensor after rotating the drum, and measures a changed amount in water level by comparing the level of water measured before rotating the drum to the level of water measured after rotating the drum to determine whether the laundry is dry cloth or wet cloth.

15. The washing machine according to claim 14, wherein if a changed amount in water level is measured, the controller determines that the laundry is wet cloth.

16. The washing machine according to claim 12, wherein the controller determines a weight of the laundry using an acceleration time taken for the washing motor to reach a predetermined velocity when predetermined torque is applied to the washing motor.

17. The washing machine according to claim 16, wherein if it is determined that the laundry is wet cloth, the controller performs a wetting process to wet the laundry before determining a weight of the laundry.

18. The washing machine according to claim 12, wherein the controller determines whether the laundry is dry cloth or wet cloth according to the changed amount in water level, and determines a weight of the laundry using different weight criterion depending on whether the laundry is dry cloth or wet cloth.

19. The washing machine according to claim 16, further comprising a memory having a wet cloth table and a dry cloth table,

wherein the controller estimates the weight of the laundry using the wet cloth table or the dry cloth table corresponding to the acceleration time.

20. The washing machine according to claim 19, wherein, when the controller utilizes the wet cloth table, the controller estimates the weight of the laundry using the wet cloth table after a adding a weight to the wet cloth table according to the changed amount in water level.