Basket Acceleration and Coast-Time Sensing for Washer Load Mass

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Solution Overview

Problem

Existing washing machine technologies face challenges in accurately determining load masses, leading to suboptimal performance due to complex and costly methods or inaccuracy, which are not viable for commercial use.

Innovation Solution

A method and apparatus that accelerate the washing machine basket from a first speed to a second speed, measure check speed and acceleration time, and then coast back to the first speed to determine load mass based on these parameters, using a controller to calculate the load mass effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex software and sensors are used to determine load mass, then measurement precision may be improved, but device complexity and cost increase

Engineering Contradiction:

Improveload mass determination accuracyVSAvoidsoftware and sensor complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex electronic sensors and software-based load detection systems with a mechanical measurement approach. By using the motor's existing acceleration and coasting characteristics to determine load mass, the invention eliminates the need for additional load cells, strain gauges, or complex sensor arrays, thereby reducing device complexity while maintaining measurement capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses the motor's own operational characteristics (acceleration and deceleration behavior) to self-determine the load mass. The motor controller measures how the motor accelerates the basket during wash cycles and how it coasts to a stop, using these inherent mechanical responses to infer load mass without requiring external measurement devices

Inventive Principle:

Principle #25Self-service

2Measurement precision

If calibration procedures are implemented to improve measurement accuracy, then measurement precision improves, but ease of operation deteriorates

Engineering Contradiction:

Improveload mass determination accuracyVSAvoidcalibration requirement

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The system performs automatic self-calibration during normal wash cycle operation by measuring the motor's acceleration and coasting characteristics. The controller continuously monitors these parameters and uses them to determine load mass in real-time, eliminating the need for manual calibration procedures by the user

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system establishes baseline acceleration and coasting characteristics during initial system operation or manufacturing, storing these reference values in memory. These pre-established parameters are then used during subsequent wash cycles to accurately determine load mass without requiring user intervention for calibration

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the basket acceleration profile is optimized for speed, then productivity improves, but measurement precision of load mass deteriorates

Engineering Contradiction:

Improvewash cycle speedVSAvoidload mass determination accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system uses periodic measurement intervals during the wash cycle, specifically measuring acceleration at the beginning of cycles and coasting characteristics at the end. This periodic sampling approach allows the system to maintain high productivity during the main wash phases while still gathering sufficient data for accurate load mass determination at key measurement points

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

This approach provides a cost-effective, accurate, and simplified method to determine load mass, allowing for tailored appliance performance and improved wash efficiency without the need for complex calibration or sensors.

Implementation Method 1

measuring a coast time for coasting of the basket from the check speed to the first speed

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

measuring, during the accelerating step, an acceleration time for the tub to accelerate from the first speed to the second speed

Methodology Applied

Scientific EffectMoment of Inertia: Moment of Inertia

Data Source

PatentUS9840805B2Methods for determining load mass in washing machine appliances

Publication Date: 2017.12.12 HAIER US APPLIANCE SOLUTIONS INC

AI summary

Washing machine appliances and methods for determining load masses are provided. A method includes accelerating rotation of a basket of the washing machine appliance from a first speed to a second speed greater than the first speed and for a predetermined time measured for acceleration of the basket from the first speed; measuring, during the accelerating step, a check speed of the basket at the predetermined time; and measuring, during the accelerating step, an acceleration time for the tub to accelerate from the first speed to the second speed. The method further includes discontinuing acceleration of the basket after the second speed and the predetermined time have reached; and measuring a coast time for coasting of the basket from the check speed to the first speed. The method further includes determining a load mass in the basket based on the check speed, the acceleration time, and the coast time.