KR100186573B1 - Laundry weight sensing method of drum type washing machine - Google Patents

Abstract

The present invention relates to a drum type washing machine, and more particularly, to a drum type laundry detecting method for accurately detecting the amount of laundry in a drum type washing machine, The time required for accelerating the drum, the RPM vibration amount and the average RPM are measured, and compared with the programmed experimental value determined in advance by experiment, it is possible to improve the bulk detection performance by detecting the bulk amount.

Description

Detection method of drum washing machine

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a drum type washing machine, and more particularly, to a drum type laundry quantity detecting method for accurately detecting the amount of laundry.

1, a tub 20 is fixed in a main body 10, and a driving force of a BLDC motor 40 is transmitted through a belt 41 into a tub 20, A plurality of baffles 31 are fixed to the inner circumferential surface of the drum 30 in a state where the baffles 31 are held at a predetermined angle so as to raise the laundry.

A sensor hose 60 is connected to a lower portion of the tub 20 and an amount of water filled into the tub 20 is sensed at an end of the sensor hose 60 to transmit the sensed signal to the system controller 70 A water level sensor 50 is provided.

Referring to FIG. 2, the system controller 70 of the drum washing machine constructed as described above includes a converter 71 for DC-converting 220 V AC power, a DC power source 71 for outputting DC power from the converter 71, A rotation speed sensing unit 73 for sensing the rotation speed of the BLDC motor 40 and a water level sensor 50 for sensing the water level in the washing tub 20 via the water level sensor 50. [ A control unit 75 for generating control signals in response to various input signals such as a water level sensing unit 74 and a rotation speed sensing unit 73, And a gate driver 76 for outputting a driving signal in accordance with a control signal.

A conventional method for detecting the amount of laundry in the drum washing machine constructed as above will be described with reference to the accompanying drawings.

FIG. 3 is a flow chart for detecting the drum washing amount of the drum washing machine according to the related art, and FIG. 4 is a view showing a drum washing machine drum washing detecting principle according to the related art.

Referring to FIG. 3, when the washing cycle is started, wash water is supplied to a level set by the user (S100).

Next, the controller 75 sends a gate drive control signal and a PWM control signal to drive the BLDC motor 40. The drum unit 30 is agitated in a constant manner to the left and right so as to allow the washing water to evenly flow into the drum (S102 ).

At this time, when the bubble absorbs the washing water by the left and right stirring of the drum 30, the water level falls below the set water level (see Fig. 4). (See Fig. 4)

Then, the cannon absorbs the wash water, and the water level falls below the set water level to judge whether re-watering is necessary (S103).

If it is determined in step S103 that refeeding is necessary, the left and right stirring of the drum 30 is stopped and water supply is again performed to the set water level (S104), and the stirring of the drum 30 is repeated.

This process is repeatedly performed for a predetermined time t1, and the number of re-watering is counted (S105).

When the predetermined time t1 has elapsed (S101), the amount of replenishment is judged according to the number of re-feeding counted for a predetermined time t1 (S106). If the number of re-feeding is small, It is determined that the amount is large.

Here, the criteria for determining the amount of replenishment according to the number of times of re-feeding is determined in advance through experimentation and is programmed in the control unit 75. [

For example, if the number of re-watering is less than 2, it is determined that the amount is less than 2 kg, and if the number of re-watering is more than 7, it is determined that the amount is 5 kg or more.

If it is determined that the amount of replenishment is determined according to the number of times of re-feeding, the washing cycle is performed by the determined amount (S107).

The conventional method of detecting the amount of laundry in the drum type washing machine takes a long time because it counts the number of re-watering for a certain period of time after the water supply and detects the amount of the re-watering.

In addition, there is a problem that it is difficult to accurately detect the amount of water because the water absorption rate and the water absorption rate, which absorb water, are different depending on the quality of the cloth and the type of oil (oil, soil, etc.) and water supply speed.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a method of detecting a drum washing machine for detecting an accurate drumming amount by accelerating the drum in a dry state.

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

2 is a block diagram of a control drive of a general drum type washing machine,

FIG. 3 is a flow chart for performing drum detection of a drum type washing machine according to the prior art,

FIG. 4 is a view showing the principle of detecting the amount of laundry in a drum type washing machine according to the related art,

FIG. 5 is a graph showing the rotational speed of the drum washing machine according to the present invention,

FIG. 6 is a flow chart for performing the drum washing detection of the drum washing machine according to the present invention,

FIG. 7 is a view showing the principle of RPM vibration by eccentricity of a drum of a drum type washing machine according to the present invention,

8 is a graph showing the correlation between the amount of laundry, the acceleration time, the amount of laundry, and the amount of RPM vibration in the drum washing machine according to the present invention,

9 is a graph showing a correlation between a power supply voltage and an average RPM of the drum type washing machine according to the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

40: BLDC motor 50: water level sensor

71: converter section 72: inverter section

73: rotation speed sensing unit 74: water level sensing unit

75: control unit 76: gate driver

A method of detecting a drum washing machine according to the present invention includes measuring a time required for a drum to be accelerated to a predetermined speed, a RPM vibration amount and an average RPM by accelerating the drum with a PWM signal having a duty set in a dried dry state of laundry, It has a characteristic that it can accurately detect the amount of waste because it detects the amount of waste compared with the experimental value determined and experimented in advance.

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

FIG. 5 is a graph showing the rotational speed of the drum washing machine according to the present invention when the drum washing machine detects the drum washing amount, and FIG. 6 is a flow chart for detecting drum washing amount of the drum washing machine according to the present invention.

FIG. 7 is a graph showing the principle of RPM oscillation due to eccentricity of a drum of a drum type washing machine according to the present invention, FIG. 8 is a graph showing a correlation between a drum type laundry amount, an acceleration time, And FIG. 9 is a graph showing the relationship between the power supply voltage and the average RPM of the drum washing machine according to the present invention.

First, the internal construction of the drum washing machine and the construction block diagram of the control drive for implementing the present invention are the same as those of FIGS. 1 and 2.

5 and 6, a method for detecting the amount of laundry in the drum type washing machine according to the present invention will be described.

First, when the controller 75 drives the BLDC motor 40 with a PWM signal having a duty (DUTY) set (S200), the drum 30 is accelerated by the rotation torque of the BLDC motor 40.

In this case, the duty is a ratio of the ON time to the time of a clock of the PWM waveform. When the duty is low, the voltage is applied low and the speed of the BLDC motor 40 becomes slow. When the duty is high, So that the speed of the BLDC motor 40 is accelerated.

The acceleration time t _{a which} is the time required to reach the constant RPM1 is measured (S202) when the RPM is equal to or higher than the constant RPM1 (S201).

Here, the constant speed RPM1 is a speed at which the centrifugal force is greater than the gravitational force of the gun so that the dropping motion of the gun does not occur at constant speed after the acceleration of the drum 30 is completed.

The acceleration time (t _a ) is determined by the torque of the motor and the inertia of the drum in the equation of motion of the drum. The equation of motion in the drum is the equation of motion of the drum:

[Equation 1]

Tm-mg * sin (?) *? = J * (dw / dt) + B * W

(mg * sin (?) *?: gravitational rotation direction component of the gun, J: inertia of the drum and gun, and B: friction coefficient). Here, the torque equation (Tm) of the motor is

&Quot; (2) "

Tm = C * PWM duty * Vdc-Ke * W

(Vdc: power supply voltage, W = RPM * 2 * 3.14 / 60: rotational angular velocity).

Therefore, the acceleration time (t _a) is proportional to the inertia (J), and also becomes the torque of the motor increases the power supply voltage is high to shorten the acceleration time (t _a) as in the 7, 8 and 9 at the same time the average RPM .

The acceleration time of the same to reach the predetermined speed (RPM1) (t _a) after a measurement, when a predetermined time (t _s) has elapsed, and the acceleration of the drum 30 is completed (S203), the drum (30) (Max, Min RPM difference) and the average RPM are measured by sensing Max and Min RPM during one rotation (S204) (S205).

Referring to FIG. 7, when the cause of the RPM vibration is described, the bubbles in the drum 30 are gathered on one side (lower side) due to gravity before the detection of the discharged amount. When the rapid accumulation is accelerated by centrifugal force and acceleration, The dropping motion does not occur in the drum, so that the pores in the drum occur.

When the tangential component (mg * sin (?) *?) Of the gravity component of the gravity component is added to the rotational torque by the eccentricity due to the bias of the gun and the component changes in accordance with the position (angle a) Lt; / RTI >

Further, as shown in FIG. 8, the RPM vibration amount is determined according to the deflection amount (blast amount). When the foam amount increases, the vibration amount increases to some extent and decreases again.

This is because when the drum is more than half of the drum, the eccentricity of the drum is canceled and is reduced.

The amount of acceleration (t _a ), RPM vibration amount (RPMf), and average RPM (RPMavg) measured in this manner are compared with the experimental values determined in advance by experiment and programmed to determine the amount of explosion (S206).

For example, in the case of 70RPMavg71,

RPMf2, and when t _a 300 ms, the replenishment amount is determined to be 0 to 0.5 kg, and RPMf 2, and when t _a 400 ms, the replenishing amount is determined to be 5.5 to 6 kg.

Then, when 2RPMf3 and t _a 400ms, the replenishment amount is determined to be 0.5 to 1 kg.

Also, when 71RPMavg72,

If RPMf2 and t _a 280ms poryang is determined to be 0 ~ 0.5kg, and t is RPMf2 _a 380ms poryang is determined to be 5.5 ~ 6kg.

Then, if 2RPMf3 and t _a 280ms, the replenishment amount is determined to be 0.5 to 1 kg.

If the quantity is determined as such, the remaining steps corresponding to the determined quantity are proceeded (S207).

The method for detecting the amount of laundry in the drum type washing machine according to the present invention can detect an accurate amount of laundry since it is not influenced by water absorption rate, absorption rate, water supply rate,

Therefore, the washing, rinsing, dewatering and drying processes after the detection of the full amount can be efficiently performed by the accurate detection of the full amount, so that energy and time can be saved and the washing performance can be improved.

Claims (2)

In a washing machine equipped with a motor, measuring the time until the motor is accelerated at a constant speed; Calculating an RPM vibration amount and an average RPM after acceleration of the motor; And determining a quantity corresponding to the measured time, the RPM vibration amount, and the average RPM according to a preset experimental value. The method of claim 1, wherein the predetermined speed is a speed at which the centrifugal force is not greater than a gravitational force so that a falling motion does not occur.