Washer Motor Current Signatures for Fabric Type Detection

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Solution Overview

Problem

Existing laundry treating appliances cannot reliably detect the type of fabric or garments in a load without using expensive sensors or increasing cycle time, while optimizing operation cycles to minimize water and energy usage.

Innovation Solution

A method and apparatus that determine the size and type of laundry load by measuring the difference between in-rush and steady-state current of an electric motor during mechanical energy application, using a controllable liquid supply and sensors to adjust liquid volume and agitation, allowing for efficient cycle optimization without expensive sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If expensive sensors are used to detect fabric type, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvefabric type detection accuracyVSAvoidsensor system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces expensive mechanical/optical fabric type sensors with an electrical measurement system. By measuring the electrical current drawn by the motor during agitation, the system infers fabric type based on the mechanical resistance characteristics of different fabric materials. This substitution eliminates complex sensing hardware while maintaining detection capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The motor serving the agitation function also provides sensing capability through its current draw characteristics. The same component that performs mechanical agitation (the motor) simultaneously serves as the sensor by providing electrical signal information that reflects the mechanical load characteristics of different fabric types. This self-service approach eliminates the need for separate sensing components.

Inventive Principle:

Principle #25Self-service

2Measurement precision

If traditional sensing methods are used to detect fabric type, then measurement precision is improved, but loss of time increases due to extended cycle time

Engineering Contradiction:

Improvefabric type detection accuracyVSAvoidcycle time extension

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs fabric type detection continuously during the agitation phase of the wash cycle. Rather than pausing the cycle to perform separate sensing operations, the motor current measurements are taken continuously throughout the agitation process, allowing fabric type determination to occur simultaneously with the useful washing action, thus avoiding cycle time extension.

Inventive Principle:

Principle #20Continuity of useful action

3Productivity

If load mass detection is performed using dry sensing, then productivity is improved through faster operation, but measurement precision of fabric type deteriorates

Engineering Contradiction:

Improveoperational speedVSAvoidfabric type detection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system changes the measurement parameter from dry mechanical properties (used in traditional load sensing) to electrical current characteristics during agitation. By measuring the electrical current drawn by the motor when agitating the load, the system can determine fabric type based on the electrical signature that reflects the mechanical resistance of different fabric materials, achieving both speed and accuracy.

Inventive Principle:

Principle #35Parameter changes

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

Enables accurate detection of laundry load type and efficient water and energy usage by optimizing liquid supply and agitation based on motor current signatures, reducing cycle time and costs.

Implementation Method 1

applying mechanical energy to the laundry treating chamber by driving a clothes mover with an electric motor

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

determining a difference between an in-rush current to the electric motor and a steady-state current of the electric motor

Methodology Applied

Scientific EffectElectrical resistance measurement: Electrical Resistance

Data Source

PatentUS9945060B2Method to determine fabric type in a laundry treating appliance using motor current signature during agitation

Publication Date: 2018.04.17 WHIRLPOOL CORP

AI summary

Disclosed is a method of operating a laundry treating appliance having a treating chamber that receives a laundry load for treatment according to a cycle of operation. The method includes determining the size of the laundry load in the treating chamber; supplying a predetermined amount of liquid to the treating chamber based on the determined load size; applying mechanical energy to the laundry treating chamber by driving a clothes mover with an electric motor; determining a difference between an in-rush current to the electric motor and a steady-state current of the electric motor during the applying of the mechanical energy; and determining a laundry load type of the laundry load based on the determined difference.