Washing Machine Unbalance Control for Faster Dehydration
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Solution Overview
Problem
Washing machines face challenges in efficiently reducing wash tub unbalance, particularly when dealing with large or bulky items, leading to increased dehydration time or failure, due to inadequate dispersion of fabric during the washing process.
Innovation Solution
A control method for washing machines that adjusts water supply levels based on detected fabric unbalance, using a pulsator and motor control system to rotate the wash tub at specific speeds and directions, optimizing water levels and rotation to prevent fabric collection on one side and ensure balanced dehydration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the wash tub is rotated at high speed for dehydration, then dehydration efficiency is improved, but fabric collection on one side causes excessive vibration and collision between wash tub and water storage tub
Solution Approach 1:
The system performs preliminary unbalance detection and fabric dispersion operations before initiating high-speed dehydration. The control unit detects unbalance during acceleration and alternately rotates the wash tub in opposite directions to disperse fabric, preventing excessive vibration during dehydration by addressing imbalance issues before they become problematic.
2Stability of the object's composition
If the wash tub is alternately rotated in opposite directions to disperse fabric, then fabric dispersion is improved, but the time taken to begin dehydration is excessively increased
Solution Approach 1:
The system performs fabric dispersion operations selectively rather than repeatedly. Unbalance detection is performed during acceleration phase, and alternate rotation is executed only when unbalance exceeds predetermined thresholds, avoiding excessive repetition that would waste time while still achieving sufficient fabric dispersion when needed.
Solution Approach 2:
The control unit continuously monitors unbalance levels during acceleration and uses this feedback to determine whether fabric dispersion operations are necessary. If unbalance is within acceptable ranges, the system proceeds directly to dehydration without unnecessary dispersion operations, optimizing the balance between fabric dispersion and dehydration time.
3Productivity
If the wash tub is accelerated to high speed for dehydration, then dehydration performance is improved, but unbalance detection becomes difficult due to excessive vibration
Solution Approach 1:
The system performs unbalance detection during the acceleration phase at lower speeds before reaching high dehydration speeds. The control unit detects unbalance during acceleration and completes necessary fabric dispersion operations before the wash tub reaches high speed, ensuring accurate detection is performed when vibration levels are manageable.
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
This method effectively disperses fabric within the wash tub, reducing unbalance and preventing excessive vibration, thereby ensuring efficient dehydration and preventing washing machine failure, even with large or bulky items.
Implementation Method 1
a motor configured to rotate at least one of the wash tub and the pulsator
Data Source
AI summary
A control method of a washing machine may include supplying water to a predetermined unbalance induction water level into a wash tub configured to accommodate fabric, the wash tub being rotated about a vertical axis, rotating a pulsator inside the wash tub, sensing an amount of fabric, rotating the wash tub at a constant acceleration, determining unbalance based on a current value applied to a motor in a state in which a rotational speed of the wash tub falls in a given range and the sensed amount of fabric while the wash tub is rotated at the constant acceleration, and supplying water to a first water supply level into the wash tub when the unbalance is greater than a reference value, and supplying water to a second water supply level, which is higher than the first water supply level, when the unbalance is smaller than the reference value.