KR101287535B1 - Washing machine and method for sensing a quantity of laundry - Google Patents

Abstract

The present invention relates to a washing machine and a method for detecting the amount of laundry that can accelerate the detection of the amount of laundry at a point where the slope of the speed ripple due to the unbalance of the laundry is always constant.

To this end, the present invention provides a method for detecting the amount of laundry in a washing machine for detecting the weight of the laundry by providing a drum for receiving the laundry and a motor for rotating the drum, the method comprising: detecting a drum speed according to the motor driving to extract a speed ripple; Calculating a slope of the extracted speed ripple to determine whether a predetermined reference value has been reached; And when the calculated slope of the speed ripple reaches the reference value, the drum speed is accelerated at a predetermined speed to sense the weight of the drum in the drum.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a washing machine,

1 is a view showing an unbalanced state of a drum inner shell of a washing machine.

2 is a view showing a balance state of the inner drum of the drum of the washing machine.

3 is a control block diagram of a washing machine according to an embodiment of the present invention.

FIG. 4 is a flow chart of the operation of detecting the laundry amount in the washing machine according to the present invention.

FIG. 5 is a graph showing a drum speed graph showing the laundry amount detection control of the washing machine according to the present invention.

FIG. 6 is a graph showing the acceleration time in the case where the amount of discharged water is small due to the flow rate detection control in FIG.

FIG. 7 is a graph showing the acceleration time in the case where the lot amount is detected by the lot amount detection control of FIG. 5;

Description of the Related Art [0002]

10: Drum 12: Laundry (Po)

20: input unit 22:

24: motor driving unit 26: motor

28:

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a washing machine for accurately detecting the weight of laundry, i.e., a laundry amount, by eliminating detection errors due to unbalance of laundry, and a method of detecting the laundry amount.

2. Description of the Related Art Generally, a washing machine (typically, a drum washing machine) includes a water tank for fresh water of water (washing water or rinse water), a drum rotatably installed inside the water tank, And a motor for generating a driving force for rotating the drum. When the cylindrical drum rotates, the laundry inside the drum rises along the inner wall of the drum and then falls down to perform washing.

Such a washing machine is characterized in that it comprises a washing step for separating the contamination of the cloth with the detergent-dissolved water (specifically, washing water), a rinsing step for rinsing the foam with the detergent-free water (specifically, rinsing water) And the washing is carried out by a series of operations such as the administration, the dehydration and the dehydration which speeds up the bovine dehydration. The washing machine senses the weight (bulk) of the pod in order to carry out the washing in this series of operations. The information of the pod quantity detection is used as information for setting the quantity required for washing in the washing cycle, It is used as basic information for reducing the unbalance of the gun in the past.

Conventional washing machines propose various methods for detecting the amount of laundry. Japanese Patent Laid-Open Nos. 2002-336593, 2004-267334, and 07-90077 have widely been proposed for such washing machines.

The washing machines disclosed in this publication detect the inertia amount of the drum by directly or indirectly measuring the inertia amount of the drum by applying a torque to the motor for a predetermined time and then using the second law of motion (torque = inertia ㅧ acceleration).

1, when the drum 12 is unevenly distributed in the inner space of the drum 10, unbalance occurs. In this case, when the unbalance occurs in the circumferential position of the drum 10, The error is large when the inertia amount is measured for a short time. Therefore, conventionally, the influence of unbalance has been suppressed by measuring the inertia amount for a long time.

However, when the torque is applied to the motor to measure the inertia amount for a long time, the rotational speed of the motor (rotational speed of the drum) changes greatly. For example, physical influences such as contact friction of the cloth, mechanical vibration, rotational speed detection error, power supply voltage fluctuation, and the like.

Conventionally, in order to suppress these influences, since a long time measurement is performed a plurality of times and the discharge amount is sensed by the average value, more time is consumed for the discharge amount detection, and the discharge amount can not be detected in a timely manner.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a method and apparatus for accelerating detection of a large amount of droplets at a point where a slope of a speed ripple due to unbalance of a gun is always constant, And a method for detecting the amount of the laundry.

According to an aspect of the present invention, there is provided a method for detecting a drum of a washing machine including a drum and a motor for rotating the drum to sense the weight of the drum, ≪ / RTI > Calculating a slope of the extracted speed ripple to determine whether a predetermined reference value has been reached; And when the calculated slope of the speed ripple reaches the reference value, the drum speed is accelerated at a predetermined speed to sense the weight of the drum in the drum.

In addition, the reference value is a starting point for accelerating the drum speed for detecting the drum.

Further, the reference value is characterized by a point where the slope of the velocity ripple is zero.

Also, the reference value is characterized in that the slope of the velocity ripple is any positive or negative value.

In addition, the step of accelerating the drum speed at a predetermined speed is characterized in that the drum speed is accelerated from the first rotation speed to the second rotation speed for detecting the drum speed.

Further, the first rotation speed is an acceleration starting speed of the drum for detecting the amount of laundry in the washing or dehydrating step.

The second rotation speed is an acceleration end speed of the drum for detecting the amount of laundry in the washing or dewatering cycle, and is an arbitrary speed reference value that is larger or smaller than the first rotation speed.

In addition, the washing machine of the present invention comprises a drum for containing a pail; A motor for rotating the drum; The speed of the motor is detected to extract the speed ripple, and the inclination of the extracted speed ripple is calculated to accelerate the drum speed at a predetermined speed to detect the weight of the drum in the drum when the predetermined reference value is reached .

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 is a control configuration diagram of a washing machine according to an embodiment of the present invention.

3, the washing machine of the present invention includes an input unit 20 for inputting a user's operation command including settings for washing and dewatering, a control unit 22 for controlling the overall operation of the washing machine such as washing and rinsing and dewatering, A motor driving unit 24 for driving a motor 26 for rotating the drum 10 under the control of the controller 22 and a motor speed signal corresponding to the rotational speed of the drum 10 to the control unit 22 And a speed detector 28 for detecting the speed of the motor.

The control unit 22 stores in advance the speed patterns rpm1 and rpm2 of the drum for detecting the amount of laundry when the laundry is washed and the laundry is discharged. The speed pattern of the drum 10 for detecting the lotion is differently applied in the washing and dewatering strokes and may also vary depending on the radius of the drum 10. [

The first rotational speed rpm1 is about 75 rpm (for example, in the case of a small / medium-sized drum), and the second rotational speed rpm2 is about 50 rpm. Is set to a value obtained by adding about 50 rpm to the first rotation speed rpm1.

On the other hand, in the case of the dewatering stroke, the mass detection is for measuring the weight of the cloth, in which the first rotation speed rpm1 is about 98 rpm (for example, in the case of small and medium type drums) The speed rpm2 is set to a value obtained by adding about 50 rpm to the first rotation speed rpm1. The reason why the first rotation speed rpm1 in the dewatering stroke is set to be higher than the washing stroke is that the force required to rotate the drum 10 is greater due to the weight of the cloth.

The second rotation speed rpm2 can be set to an arbitrary speed reference value that is greater than or less than the first rotation speed rpm1 and the drum 10 can be accurately N (integer) It can be defined as the speed until the wheel turns. This can be changed depending on the size of the drum 10. [

When the speed ripple due to the unbalanced load occurs in the section for accelerating the speed of the drum 10 from the first rotation speed rpm1 to the second rotation speed rpm2 for the detection of the amount of waste, Acceleration (from rpm1 to rpm2) occurs at the point where the gradient is always constant (the starting point for accelerating the drum speed).

For this, the control unit 22 extracts velocity ripples by unbalance from the motor speed signal received from the speed detection unit 28 to calculate the slope of the speed ripple, and calculates the slope of the calculated speed ripple based on a predetermined starting point (Rpm1) to the second rotation speed (rpm2) to detect the amount of the drum 10 when it reaches the first rotation speed (rpm1, 0 or any positive / negative value) To the second rotation speed (rpm2).

Hereinafter, the operation and effect of the washing machine and the method for detecting the amount of the laundry will be described.

FIG. 4 is a flow chart showing the operation of detecting the amount of laundry in the washing machine according to the present invention. In FIG. 4, in order to detect the amount of laundry during washing or dehydration, And the like.

When the user inputs a driving command including the setting of the washing or dehydrating operation through the input unit 20 in a state in which the cloth 12 of dry cloth or cloth is accommodated in the drum 10, The controller 22 performs a series of operations for performing a dewatering process through the washing and rinsing steps, thereby proceeding the washing process.

Accordingly, the control unit 22 determines whether or not the laundry is being inspected (step 100), and if the laundry is in the laundry detection period, And controls the driving of the motor 26 to rotate the drum 10 (102).

At this time, the motor speed signal corresponding to the rotation speed of the drum 10 is detected by the speed detection unit 28 and transmitted to the control unit 22 (104). The control unit 22 detects the motor speed signal from the drum 10 ), It is determined whether the speed has reached the first rotation speed rpm1 as shown in Fig. 5 (106).

Controls the driving of the motor 26 until the speed of the drum 10 reaches the first rotation speed rpm1 when the speed of the drum 10 does not reach the first rotation speed rpm1, The control unit 22 controls the driving of the motor 26 through the motor driving unit 24 so that the speed of the drum 10 is controlled to the first rotation speed rpm1 as shown in FIG. And is maintained at the rotational speed rpm1 (108).

The state of the drum 12 in the drum 10 in a state where the speed of the drum 10 is maintained at the first rotational speed rpm1 is ideally equal to the state of the drum 12 as shown in Fig. It should be uniformly distributed along the inner wall. However, in many cases, as shown in Fig. 1, the plug 12 is unevenly distributed unevenly.

As shown by the dotted line in FIG. 5, such a load unbalance generates one speed ripple per one rotation of the drum 10, and this speed ripple causes an error in detection of the amount of discharged fluid.

For example, when acceleration is started by applying a constant torque to the motor 26 when the speed of the drum 10 is decelerated due to unbalance, the acceleration time? T is increased, thereby detecting an error Occurs.

On the other hand, when the acceleration is started by applying a constant torque to the motor 26 in the acceleration period of the speed ripple due to the unbalance, the acceleration time? T is decreased to generate an error to detect a smaller quantity than the original quantity.

Therefore, in order to eliminate such an unbalance detection error, the control unit 22 extracts the ripple of the speed of the drum 10 from the motor speed signal transmitted from the speed detector 28 (110) The slope is calculated (112).

Accordingly, the control unit 22 determines (114) whether the calculated slope of the speed ripple reaches a predetermined reference value (a starting point for accelerating the drum speed for detecting the drum speed) to accelerate the drum speed, , And accelerates the speed of the drum 10 from the first rotational speed rpm1 to the second rotational speed rpm2 when the slope of the speed ripple reaches the start point for detecting the amount of the drum.

At this time, the starting point for accelerating the speed of the drum 10 is set to a point where the slope (acceleration) of the speed ripple at point (A) or (B) The acceleration (acceleration) of the velocity ripple at point C or D may be negative or positive.

In FIG. 5, when the point (A) or (B) is used as the starting point of the bulk detection, there is an advantage that only the weight of the uniformly distributed pouch 12 is estimated except for the unbalance. The unbalance torque increases in proportion to the unbalance and the unbalance torque increases the load torque, so that the weight of the bag 12 including the unbalance can be estimated.

Therefore, the starting point for accelerating the speed of the drum 10 can be set to an optimum value according to the size of the drum 10 or various load conditions.

The control unit 22 determines whether the speed of the drum 10 reaches the second rotation speed rpm2 when the motor 26 starts to accelerate by applying a constant torque to the motor 26. If the speed of the drum 10 reaches the second rotation speed rpm2, (120) using the time (? T) taken for the speed of the drum (10) to accelerate from the first rotation speed (rpm1) to the second rotation speed (rpm1) when reaching the second rotation speed (rpm2) .

More specifically, the equation of motion of the rotating body (specifically, the drum) is expressed by [Expression 1].

J (dw / dt) = T _e - B w - T _L [Formula 1]

Here, J is a number of inertial of the drum 10, including the fabric, w is the angular velocity of the drum 10, T _e is the torque of the motor (20), B is the coefficient of friction, T _L is a load torque, t is time .

Therefore, when the drum 10 containing the cloth 12 is accelerated to a certain rpm by acceleration at a constant torque as shown in FIG. 5, [Equation 1] can be modified as shown in [Equation 2] below.

J = (T _e - B w - T _L ) (dt / d w )

J = k dt ( k is a constant)

That is, the inertia coefficient J of the drum 10 including the boss can be estimated through a database or the like using the time dt taken for acceleration. At this time, since the weight and inertia of the drum 10 are always constant, the weight (bulk amount) of the papermaking 12 can be estimated.

Therefore, as shown in Fig. 6, when the pod 12 of a small amount LOAD1 is placed in the drum 10 and accelerated, and when the pod 12 of a large amount LOAD2, as shown in Fig. 7, (T _LOAD2 > t _LOAD1 ) is changed by adding inertia as much as the weight of the capsule 12 when the capsule 12 is accelerated.

Accordingly, the control unit 22 estimates the quantity of the drum 10 using the time? T taken for the speed of the drum 10 to accelerate from the first rotational speed rpm1 to the second rotational speed rpm2.

As described above, according to the washing machine of the present invention and the method of detecting the amount of the laundry, the acceleration for detecting the amount of laundry can be accelerated at a point where the slope of the speed ripple due to the unbalance of the laundry is always constant, Can be effective.

Claims (10)

A method for detecting the amount of laundry in a washing machine for detecting the weight of the laundry by a drum having a drum and a motor for rotating the drum, Detecting a drum speed according to the motor driving to extract a speed ripple; Calculating a slope of the extracted speed ripple to determine whether a predetermined reference value has been reached; And when the calculated slope of the speed ripple reaches the reference value, the drum speed is accelerated at a predetermined speed to sense the weight of the drum in the drum. The method according to claim 1, Wherein the reference value is a starting point for accelerating the drum speed for detecting the amount of laundry. The method according to claim 1, Wherein the reference value is a point at which the slope of the velocity ripple is zero. The method according to claim 1, Wherein the reference value is a positive or negative slope of the speed ripple. The method according to claim 1, Accelerating the drum speed at a predetermined speed, Wherein the drum speed is accelerated from the first rotation speed to the second rotation speed for detecting the amount of waste. 6. The method of claim 5, Wherein the first rotation speed is an acceleration start speed of the drum for detecting the amount of laundry in a washing or dewatering cycle. The method according to claim 6, Wherein the second rotational speed is an acceleration ending speed of the drum for detecting the amount of laundry in the washing or dewatering step and is an arbitrary speed reference value that is larger or smaller than the first rotational speed. A drum for receiving the can; A motor for rotating the drum; The speed of the motor is detected to extract the speed ripple, and the inclination of the extracted speed ripple is calculated to accelerate the drum speed at a predetermined speed to detect the weight of the drum in the drum when the predetermined reference value is reached And a controller for controlling the washing machine. 9. The method of claim 8, Wherein the reference value is a point at which the slope of the velocity ripple is zero. 9. The method of claim 8, Wherein the reference value is a positive or negative slope of the velocity ripple.

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