Laundry Machine Drum Speed Control for Transient Vibration Reduction
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Solution Overview
Problem
Laundry machines generate significant noise and vibration during the spinning cycle due to unbalanced drum rotation, which existing technologies have not adequately addressed.
Innovation Solution
A control method that includes vibration sensing, transient region identification, and drum rotation speed control to prevent shock and noise by using a suspension assembly and balancers to manage unbalance, allowing the drum to pass through a wide transient vibration region while maintaining minimal noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drum rotates at high speed during spinning cycle, then dehydration efficiency is improved, but noise and vibration increase significantly
Solution Approach 1:
The control method performs preliminary actions by detecting vibration before it reaches excessive levels and proactively adjusting drum speed to prevent harmful vibration and noise, rather than reacting after the problem occurs. This is achieved through continuous vibration monitoring and predictive speed control.
Solution Approach 2:
The system implements feedback control by continuously detecting drum vibration levels and using this information to adjust the motor speed accordingly. When vibration exceeds predetermined thresholds, the controller reduces speed to maintain acceptable noise and vibration levels while still achieving dehydration goals.
2Object-generated harmful factors
If the drum speed is reduced to minimize vibration, then noise and vibration are reduced, but spinning cycle time increases
Solution Approach 1:
The control method employs periodic action by alternating between high-speed operation (when vibration is acceptable) and speed reduction (when vibration thresholds are exceeded). This allows the system to achieve dehydration efficiency during low-vibration periods while minimizing noise and vibration during high-speed periods, optimizing the overall spinning cycle.
Solution Approach 2:
The system dynamically changes operational parameters by adjusting motor speed based on real-time vibration conditions. The controller modifies speed parameters predictively before vibration becomes excessive, allowing the drum to operate at efficient high speeds during acceptable vibration ranges while preventing harmful vibration levels, thus optimizing both time and vibration control.
3Loss of time
If the drum passes through the transient vibration region quickly, then cycle time is reduced, but shock and noise from unbalance increase
Solution Approach 1:
The control method applies skipping by enabling the drum to rapidly pass through the problematic transient vibration region (approximately 200-400 RPM) where unbalance causes excessive shock and noise. The system detects when the drum enters this region and accelerates through it quickly, minimizing the time spent in the harmful vibration zone while preventing prolonged exposure to shock and noise.
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
Effectively reduces noise and vibration by ensuring balanced drum rotation and controlled speed changes, enhancing the spinning cycle efficiency and user experience.
Implementation Method 1
a vibration sensing unit configured to sense vibration of the drum
Implementation Method 2
a suspension assembly connected to the driving unit
Implementation Method 3
a suspension assembly connected to the driving unit
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A control method of a laundry machine is disclosed. The control method of a laundry machine includes a vibration sensing step configured to sense vibration of a drum (320), transient region passing identifying step configured to identify transient region passing of the drum (320) in case the vibration of the drum (320) sensed in the vibration sensing step is a preset vibration value or more and a drum rotation speed controlling step configured to control the rotation speed of the drum (320) based on whether the rotation speed of the drum (320) passes a transient region.