Control method of a laundry machine

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Solution Overview

Problem

Laundry machines lack an effective control method to optimize drum rotation motions for improved washing performance, energy efficiency, and customer satisfaction, as existing methods often result in inefficient contaminant removal and increased noise/vibration.

Innovation Solution

A control method that diversifies drum driving motions by alternating rotation directions and speeds, applying sudden braking, and varying rotation angles to simulate hand-wash effects, including rolling, tumbling, striking, swinging, rubbing, and filtration motions, optimized for different laundry types and soil levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the drum rotates at a constant speed in a single direction, then the structure is simple and easy to control, but the washing performance is insufficient and contaminant removal is inefficient

Engineering Contradiction:
Improvewashing performanceVSAvoidcontrol method complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The drum rotation system transitions from static constant-speed single-direction rotation to dynamic multi-speed bidirectional rotation with variable acceleration and deceleration phases. The control method implements at least three different rotation speeds including a high-speed rotation phase and a low-speed rotation phase, with automatic direction reversal, creating dynamically varying mechanical forces that enhance contaminant removal effectiveness.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control method implements periodic alternation between clockwise and counter-clockwise rotation directions, with each direction containing sequential high-speed and low-speed phases. This periodic variation in rotation speed and direction creates repeating cycles of mechanical action that systematically work loose and remove contaminants from laundry items over time.

Inventive Principle:
Principle #19Periodic action

2Productivity

If the drum rotates at high speed continuously, then the washing action is strong, but noise and vibration increase

Engineering Contradiction:
Improvecontaminant removal efficiencyVSAvoidnoise and vibration
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The control method implements periodic alternation between high-speed and low-speed rotation phases, and between clockwise and counter-clockwise directions. During high-speed phases, strong washing action removes contaminants, while low-speed phases reduce noise and vibration levels. This periodic cycling maintains effective contaminant removal while limiting exposure to harmful noise and vibration.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The control method alternates the direction of drum rotation between clockwise and counter-clockwise. By reversing the rotation direction, the patent creates varying mechanical forces that prevent the drum from consistently operating at high noise and vibration levels in one direction, while maintaining effective washing action through the alternation.

Inventive Principle:
Principle #13The other way round (Inversion)

3Object-affected harmful factors

If the drum rotates at low speed, then noise and vibration are reduced, but contaminant removal becomes inefficient

Engineering Contradiction:
Improvenoise and vibrationVSAvoidcontaminant removal efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The control method implements periodic alternation between low-speed phases (reducing noise and vibration) and high-speed phases (enhancing contaminant removal). The low-speed phases are interspersed with high-speed phases, ensuring that while noise and vibration are reduced during low-speed operation, the overall contaminant removal efficiency is maintained through the cumulative effect of repeated high-speed washing cycles.

Inventive Principle:
Principle #19Periodic action

4Productivity

If the drum changes rotation direction frequently, then washing effectiveness is improved through varied mechanical forces, but energy consumption increases

Engineering Contradiction:
Improvewashing effectivenessVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The control method implements periodic direction changes between clockwise and counter-clockwise rotation, with each direction containing multiple high-speed and low-speed phases. By organizing direction changes in a structured periodic pattern rather than continuous random switching, the patent achieves varied mechanical forces for effective washing while minimizing unnecessary energy consumption from excessive direction reversals.

Inventive Principle:
Principle #19Periodic action

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

Enhances washing efficiency, reduces washing time, and minimizes noise and vibration, providing improved customer satisfaction through optimized mechanical forces and laundry distribution within the drum.

Implementation Method 1

friction between the laundry items, wash water and wash agents, and the interior of the drum, may facilitate contaminant removal from the laundry items

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

applying a sudden braking to the drum when the rotation angle of the drum is 90 to 180

Methodology Applied
Scientific EffectImpact force: Impact Force

Data Source

PatentEP2496748B1Control method of a laundry machine
Publication Date: 2021.08.11 LG ELECTRONICS INC
  • EP2496748B1 patent drawingFigure 1~2
  • EP2496748B1 patent drawingFigure 3a~3a(g)
  • EP2496748B1 patent drawingFigure 3b~3b(i3)

AI summary

A laundry machine and a control method thereof are provided in which laundering ability may be improved while also improving efficiency and noise/vibration. The laundry machine employs a plurality of drum motions by varying drum rotational speed, drum rotational direction, and drum starting and stopping point, to provide different motion of laundry items in the drum.