Washing machine control method
First Claim
1. A washing machine control method comprising steps of:
- accelerating a motor to a target rotational speed, by periodically applying to the motor a pulse width modulation (PWM) signal having a predetermined duty ratio;
storing in a memory a set of PWM values corresponding to the signal applied in said accelerating step, by sensing a rotational speed of the motor;
outputting a PWM signal having a duty ratio of zero, after the sensed motor speed reaches the target rotational speed, to allow the motor to freewheel to a stop;
computing an average of the stored PWM values;
measuring a rotational angle of the motor as the motor freewheels to a stop; and
calculating a laundry amount estimation value based on the average of the stored PWM values and the motor'"'"'s rotational angle.
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Accused Products
Abstract
A washing machine control method accurately determines an amount of laundry in the washing machine, while driving a motor coupled to a drum under load, based on a computed average of pulse width modulation values at the time of stopping the drive of a motor and the motor'"'"'s rotational angle as the motor freewheels to a stop, in order to conserve water and reduce the time required for performing a washing step. The method includes steps accelerating a motor to a target rotational speed, by periodically applying to the motor a pulse width modulation (PWM) signal having a predetermined duty ratio; storing in a memory a set of PWM values corresponding to the signal applied in the accelerating step, by sensing a rotational speed of the motor; outputting a PWM signal having a duty ratio of zero, after the sensed motor speed reaches the target rotational speed, to allow the motor to freewheel to a stop; computing an average of the stored PWM values; measuring a rotational angle of the motor as the motor freewheels to a stop; calculating a laundry amount estimation value based on the average of the stored PWM values and the motor'"'"'s rotational angle; and determining a laundry amount by comparing the calculated laundry amount estimation value to a set of laundry amount reference values stored in a lookup table. The laundry amount estimation value equals w1PWMave+w2θmotor, where PWMave is the computed average of the stored PWM values, θmotor is the measured rotational angle, and w1, and w2 are weight constants.
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Citations
8 Claims
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1. A washing machine control method comprising steps of:
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accelerating a motor to a target rotational speed, by periodically applying to the motor a pulse width modulation (PWM) signal having a predetermined duty ratio;
storing in a memory a set of PWM values corresponding to the signal applied in said accelerating step, by sensing a rotational speed of the motor;
outputting a PWM signal having a duty ratio of zero, after the sensed motor speed reaches the target rotational speed, to allow the motor to freewheel to a stop;
computing an average of the stored PWM values;
measuring a rotational angle of the motor as the motor freewheels to a stop; and
calculating a laundry amount estimation value based on the average of the stored PWM values and the motor'"'"'s rotational angle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification