Control method of laundry machine

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Solution Overview

Problem

Laundry machines generate excessive noise and vibration during the spinning cycle due to unbalanced rotation, which existing methods fail to effectively address by detecting and correcting for bubble-related unbalances in real-time.

Innovation Solution

A control method that senses the rotation speed and pulse duty of the motor during the spinning cycle to detect bubble generation and unbalance, using a balancer with movable balls to redistribute weight and reduce vibration, and implementing steps to uniformly distribute laundry and adjust rotation speed to pass through resonance regions efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the rotation speed is increased during the spinning cycle, then dehydration performance is improved, but noise and vibration increase due to bubble generation

Engineering Contradiction:
Improvedehydration performanceVSAvoidnoise and vibration
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The control method performs preliminary detection of bubble generation by monitoring motor current and rotation speed before bubbles cause severe unbalance. When bubbles are detected, the system takes preliminary corrective action by adjusting rotation speed or pausing the spinning cycle, preventing the bubble-related unbalance from developing into excessive noise and vibration while maintaining dehydration efficiency

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors motor current and rotation speed during the spinning cycle, using this feedback to detect bubble generation. Based on the feedback signal indicating bubble presence, the control method dynamically adjusts the rotation speed profile, reducing speed or pausing when bubbles are detected, thereby eliminating the harmful effects of bubble-induced unbalance while preserving optimal dehydration performance when conditions allow

Inventive Principle:
Principle #23Feedback

2Productivity

If the spinning cycle operates at high rotation speed, then dehydration efficiency is improved, but bubble generation causes unbalance and operational issues

Engineering Contradiction:
Improvedehydration efficiencyVSAvoidoperational stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The control method detects bubble generation in advance by monitoring motor current characteristics and rotation speed deviations before bubbles cause severe unbalance. When bubbles are detected, the system takes preliminary corrective action by adjusting rotation speed or pausing the spinning cycle, preventing operational instability while maintaining dehydration efficiency

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses continuous monitoring of motor current and rotation speed to provide feedback on bubble generation. Based on this feedback, the control method dynamically adjusts the spinning cycle operation, reducing rotation speed or pausing when bubbles are detected, thereby ensuring operational reliability while preserving dehydration efficiency when conditions permit

Inventive Principle:
Principle #23Feedback

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 detects and mitigates bubble-related unbalances, reducing noise and vibration by uniformly distributing laundry and optimizing rotation speed through the spinning cycle, ensuring efficient operation and user satisfaction.

Implementation Method 1

a balancer with movable balls to redistribute weight and reduce vibration

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2470705B1Control method of laundry machine
Publication Date: 2017.11.15 LG ELECTRONICS INC
  • EP2470705B1 patent drawingFigure 1
  • EP2470705B1 patent drawingFigure 2
  • EP2470705B1 patent drawingFigure 3

AI summary

A control method of a laundry machine is disclosed. A control method of a laundry machine comprising a spinning cycle includes a sensing step configured to sense a rotation speed (rpm) of a motor while increasing a pulse duty of the motor during the spinning cycle and a determining step configured to determine bubble generation inside a tub based on the sensed pulse duty and rotation speed.