Washing Machine Load Sensing for Dry vs Wet Laundry Detection
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Solution Overview
Problem
Current washing machines inaccurately detect laundry load due to indirect methods, leading to inefficient washing patterns and increased wear on laundry, and the coupling between the tub supporting member and weight detecting sensor is prone to vibration-induced release.
Innovation Solution
A method for controlling a washing machine that determines whether laundry is dry or wet by comparing detected loads, using a weight detecting sensor with screw threads of different directions to stabilize the coupling and improve load detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an indirect method based on rotational property of pulsator is used to detect laundry load, then the detection system is simple, but the measurement accuracy is poor
Solution Approach 1:
The patent replaces the indirect mechanical observation method (monitoring pulsator rotational properties) with a direct weight detection system using load cells. The load cells are installed on the tub supporting member to directly measure the weight of the laundry, providing accurate measurement without relying on indirect mechanical indicators.
Solution Approach 2:
The patent introduces load cells as intermediary devices between the tub and the detection system. These load cells serve as mediators that directly sense the weight force transmitted through the tub supporting member, enabling precise measurement of laundry load while maintaining system simplicity.
2Measurement precision
If the tub supporting member is directly coupled to the weight detecting sensor, then the load detection is accurate, but the coupling is prone to vibration-induced release
Solution Approach 1:
The patent employs asymmetric screw thread directions on the adaptor - one side has a right-hand thread and the other side has a left-hand thread. This asymmetric configuration creates different engagement characteristics for rotational forces in different directions, preventing the coupling from loosening due to drum rotation vibrations while maintaining stable weight detection.
Solution Approach 2:
The patent introduces an adaptor as an intermediary component between the tub supporting member and the load cell. This adaptor acts as a mediator that transmits the weight force accurately to the sensor while its asymmetric threaded design provides vibration resistance, solving both measurement accuracy and coupling stability requirements.
3Device complexity
If washing pattern is determined without accurate laundry state detection, then the control process is simple, but water and energy consumption increase
Solution Approach 1:
The patent implements a feedback control system where the controller receives weight detection signals from the load cells, determines the laundry state (dry or wet) based on the detected weight, and accordingly selects the appropriate washing pattern. This feedback mechanism enables energy-efficient washing by adapting the washing process to the actual laundry condition.
Solution Approach 2:
The patent changes the operational parameters of the washing machine based on the detected laundry state. When wet laundry is detected, the controller selects a washing pattern with reduced water input and adjusted washing intensity, thereby optimizing water and energy consumption according to the actual parameter condition of the laundry.
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 allows for optimal washing performance by adjusting washing patterns based on laundry state, reducing water and energy consumption, and maintaining stable sensor coupling, thereby enhancing load detection accuracy and reducing wear on laundry.
Implementation Method 1
The load cell 220 is a sensor that can detect weight using tensile force
Data Source
AI summary
A method of controlling a washing machine is provided. A first laundry load is first detected based on a rotational property of a pulsator. A second laundry load is detected based on a property that varies in accordance with a vertical load applied from a tub. Finally, it is determined if laundry loaded in the drum is in a dry state or a wet state by comparing the first laundry load with the second laundry load.