Drum Washing Machine Spin-Up Control for Eccentric Load Reduction
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Solution Overview
Problem
Conventional drum type washing machines face challenges in efficiently distributing laundry to reduce eccentric loads during the dehydration process, leading to prolonged operation times and excessive vibration and noise due to inadequate timing in raising drum speed and ineffective loosening of tangled laundry.
Innovation Solution
A drum type washing machine equipped with a speed change detector and dehydration start-up controller that continuously monitors speed changes to determine the optimal timing for increasing drum speed, along with an eccentric load determiner to adjust speed and direction for efficient laundry distribution, and a load detector to set agitating speeds based on laundry load, ensuring even distribution and minimizing eccentric loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drum speed is raised quickly to high speed for dehydration, then the dehydration efficiency is improved, but the vibration and noise increase due to uneven laundry distribution
Solution Approach 1:
The system performs preliminary actions by detecting laundry distribution state at low speed before raising drum speed. The vibration detection and distribution assessment are conducted in advance to ensure laundry is properly distributed before high-speed dehydration begins, preventing vibration and noise issues.
Solution Approach 2:
The system uses vibration sensors to continuously monitor drum vibration during low-speed rotation and provides feedback on laundry distribution state. Based on this feedback, the control unit determines whether the laundry is evenly distributed before initiating high-speed dehydration, allowing real-time adjustment of the dehydration start timing.
2Stability of the object's composition
If the agitating operation continues for a long time to loosen laundry, then the laundry distribution is improved, but the operation time increases
Solution Approach 1:
The vibration sensor provides continuous feedback during the agitating operation, allowing the system to detect when laundry distribution reaches an adequate state. This enables timely termination of the agitating operation and transition to dehydration, minimizing unnecessary operation time while ensuring proper laundry distribution.
Solution Approach 2:
The system allows the laundry to naturally settle and distribute during low-speed rotation, using the drum's own rotation and gravity to achieve distribution without requiring prolonged active agitating. The vibration detection automatically determines when distribution is sufficient.
3Speed
If the drum speed is raised at inappropriate timing, then the dehydration process starts faster, but the eccentric load increases causing abnormal vibration
Solution Approach 1:
The control unit continuously monitors vibration feedback from the drum during low-speed rotation and uses this information to determine the optimal timing for raising drum speed. By analyzing vibration patterns, the system identifies when laundry distribution is adequate and eccentric load is minimized, ensuring high-speed dehydration starts at the most appropriate moment.
Solution Approach 2:
The system replaces mechanical timing methods with sensor-based vibration detection and control algorithms. Instead of using fixed time-based or speed-based thresholds, the system uses real-time vibration analysis to dynamically determine the optimal speed increase timing, achieving more precise and adaptive control.
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 solution significantly reduces the time required for the dehydration process and overall operation by ensuring timely and effective distribution of laundry, minimizing eccentric loads and subsequent vibration and noise, thereby enhancing the efficiency and reliability of the washing machine.
Implementation Method 1
a speed change detector for detecting the change in the speed of the drum
Implementation Method 2
the speed of the drum is raised to a speed where the laundry articles are pressed onto the inner circumferential wall of the drum by centrifugal force
Data Source
AI summary
The present invention provides a drum type washing machine capable of adequately distributing the laundry articles along the inner circumferential wall of the drum at the start-up of the dehydrating operation with high probability, thereby reducing the start-up time of the dehydration. In an embodiment of the present invention, the drum is controlled to rotate at a constant speed 50 r.p.m. to agitate the laundry articles (Step S12), and the drum speed is almost continuously monitored. If the change in the speed does not exceed 1.5 r.p.m. for 0.5 second (Steps S13 through S16), the laundry articles are loosened and easy to distribute. Therefore, the drum speed is raised to 80 r.p.m. (Steps S17 and S18). If the eccentric load detected at this speed does not exceed a predetermined value (Steps S19 and S20), the laundry articles are adequately distributed along and pressed onto the inner circumferential wall of the drum. If a sudden change in the speed has been detected within a short period of time that is less than 36 milliseconds (Step S22), the laundry articles are tangled in a mass form. Therefore, the rotating direction of the drum is reversed, and the agitating direction is restarted in the opposite direction (Step S21).