Drum Washer Torque Control for Fast Laundry Weight Measurement
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Solution Overview
Problem
Existing drum type washing machines face challenges in accurately calculating the weight of laundry due to errors caused by windage loss, mechanical loss, contact friction, power supply fluctuations, and unbalance of laundry, leading to difficulties in determining the optimal water amount and rotation speed, and may be affected by resonance during measurement.
Innovation Solution
A drum type washing machine with a control mechanism that performs torque addition processes during uniform torque control, evenly dividing the rotation angle into pieces, and calculates the average rotational acceleration to accurately determine the weight of laundry within a short time, canceling the effects of unbalance and rotation speed at measurement start, and allowing for precise water content determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement is repeated several times to remove error factors, then measurement accuracy is improved, but measurement time is extended and resonance problems occur
Solution Approach 1:
The patent applies preliminary action by performing uniform torque control to stabilize the drum's rotational speed before conducting the actual laundry weight measurement. This preliminary stabilization eliminates the need for repeated measurements to account for speed variations, thereby reducing measurement time while maintaining high accuracy and avoiding resonance issues.
Solution Approach 2:
The patent changes the operational parameters by controlling the motor torque to maintain uniform rotational speed during measurement. By adjusting and stabilizing the speed parameter before measurement, the system achieves accurate results in a single measurement cycle, eliminating time loss from repeated measurements and avoiding resonance caused by prolonged operation.
2Measurement precision
If voltage or rotation speed is used to calculate inertia, then laundry weight can be calculated, but accuracy deteriorates due to various error factors
Solution Approach 1:
The patent extracts and eliminates error factors by performing uniform torque control to remove the influence of speed fluctuations, windage loss variations, and mechanical loss changes. By isolating and compensating for these error sources before measurement, the system achieves both high accuracy and reliable results without being affected by the aforementioned error factors.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the drum's rotational speed and adjusting motor torque to maintain uniform speed during measurement. This feedback mechanism compensates for disturbances in real-time, ensuring accurate and reliable laundry weight calculation despite the presence of error factors such as windage loss and mechanical loss.
3Ease of manufacture
If pulse measurement using hole IC is used, then cost is reduced, but measurement accuracy deteriorates due to nonuniformity of pulse
Solution Approach 1:
The patent applies self-service by using the inexpensive hole IC pulse measurement system in conjunction with uniform torque control. The system compensates for the inherent nonuniformity of pulse signals through active speed stabilization, allowing low-cost hardware to achieve high measurement accuracy without requiring expensive alternative sensors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables high-accuracy weight calculation of laundry within a short time, preventing resonance interference and allowing for accurate washing control and water content determination, even using inexpensive pulse measurement, while simplifying the control mechanism's implementation.
Implementation Method 1
a motor to rotate the drum, and a control mechanism to control the motor
Implementation Method 2
it is important to calculate laundry amount with high accuracy... calculates inertia by an equation of motion using an average rotational acceleration
Data Source
AI summary
Disclosed herein are a drum type washing machine and a control program therefore. The washing machine includes a control mechanism to control a motor. The control mechanism includes a torque control unit to perform torque addition processes of adding pulse type torque during only a period for which a drum makes one rotation in a uniform torque control state in which torque of the motor is uniformly controlled at least two times and to perform the second torque addition process after n+0.5 rotations of the drum (n is an integer not less than 1) on the basis of the first torque addition process, and a weight calculation unit to calculate an average value of rotational accelerations of the motor at the respective torque addition processes and to calculate a weight of laundry received in the drum based on the average value.