Drum Washing Machine Spin-Drying Control to Reduce Cycle Time
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Solution Overview
Problem
Drum type washing machines face challenges in reducing spin-drying time due to limitations in increasing spring length for vibration absorption, which affects the efficiency of laundry processing based on varying laundry weights.
Innovation Solution
A method of controlling the drum type washing machine that includes multiple spin-drying patterns, with stages of acceleration and maintenance at specific speeds, and unbalance sensing to optimize spin-drying based on laundry weight, allowing for adaptive operation to reduce spin-drying time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spring length is increased to absorb vibration from high-capacity drum rotation, then vibration absorption improves, but the cabinet size exceeds limitations
Solution Approach 1:
The patent applies dynamics by making the spin-drying pattern adaptive rather than fixed. The control unit dynamically adjusts the spin-drying process based on real-time unbalance detection, switching between different acceleration patterns (first pattern for high unbalance, second pattern for low unbalance). This dynamic adaptation allows the system to achieve effective vibration management through control strategy rather than physical spring extension, resolving the contradiction between vibration absorption and cabinet size constraints.
2Productivity
If the drum is accelerated to high speed for spin-drying, then spin-drying efficiency improves, but unbalance causes excessive vibration
Solution Approach 1:
The patent applies preliminary action by detecting unbalance at multiple stages before reaching maximum spin-drying speed. The control unit measures unbalance during the acceleration process (at first, second, and third acceleration stages) and takes corrective action by stopping the drum and redistributing laundry if unbalance exceeds thresholds. This preliminary detection and correction prevents excessive vibration before it occurs, allowing efficient spin-drying while maintaining vibration control.
Solution Approach 2:
The patent implements feedback control by continuously monitoring unbalance during drum acceleration and adjusting the spin-drying pattern accordingly. When unbalance is detected above a first threshold, the system switches from the second pattern to the first pattern, which includes stopping and redistributing laundry. This feedback mechanism ensures that spin-drying efficiency is maintained while vibration is controlled through real-time adjustments based on measured conditions.
3Reliability
If unbalance detection is performed frequently during acceleration, then vibration control improves, but spin-drying time increases
Solution Approach 1:
The patent applies segmentation by dividing the acceleration process into distinct stages (first, second, and third acceleration stages), each with specific target speeds and unbalance detection points. This segmented approach allows unbalance control at critical transition points without continuous monitoring, thereby maintaining effective vibration control while minimizing the time lost to detection and correction operations.
Data Source
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AI summary
A method of controlling a drum type washing machine is disclosed. The method includes sensing laundry weight (S10) to perform a washing cycle (a laundry weight sensing step), immediately thereafter executing a first spin-drying pattern (S20) without additional laundry weight sensing when a laundry weight value sensed at the laundry weight sensing step is equal to or less than A in a spin-drying cycle, and executing a second spin-drying pattern (S40) after sensing the laundry weight when the laundry weight value sensed at the laundry weight sensing step is greater than A in the spin-drying cycle. In a case in which the laundry weight is low, spin-drying is immediately performed without performing laundry weight sensing, whereby it is possible to reduce time necessary to sense the laundry weight.