Tub Vibration Sensing for Laundry Detection in Washer Cleaning
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Solution Overview
Problem
Conventional washing machines face challenges in sensing the presence of laundry in the drum during the tub cleaning cycle, leading to potential unbalanced rotation, noise, and energy consumption, without effectively addressing the issue in real-time without additional sensors or resources.
Innovation Solution
A washing machine equipped with a MEMS sensor to measure tub vibration, connected through SPI or I2C communication, which adjusts RPM and water temperature based on vibration displacement data to determine if laundry is present, allowing real-time sensing and controlling the tub cleaning process without separate time, water, or energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a vibration switch is used to sense laundry presence, then the sensing capability is improved, but noise and vibration are generated during high-speed drum rotation
Solution Approach 1:
The patent replaces the mechanical vibration switch with a MEMS (Micro-Electro-Mechanical Systems) sensor that uses capacitive detection principles. The MEMS sensor detects laundry presence through subtle vibration changes during drum rotation without generating the harmful noise and vibration associated with mechanical vibration switches. This substitution maintains sensing accuracy while eliminating the harmful mechanical effects.
2Measurement precision
If sensing is performed before water supply, then laundry presence is detected, but separate time, water, and energy are consumed
Solution Approach 1:
The patent merges the laundry presence sensing function with the tub cleaning course operation itself. The MEMS sensor continuously monitors vibration during the drum rotation that occurs as part of the normal cleaning process, eliminating the need for a separate pre-sensing phase. This integration allows laundry detection to occur simultaneously with water supply and heating operations, thereby eliminating additional time, water, and energy consumption.
Solution Approach 2:
The sensing operation continues throughout the drum rotation during the tub cleaning course rather than being performed as a discrete preliminary step. The MEMS sensor continuously captures vibration data during the entire cleaning process, ensuring laundry presence is detected without interrupting or extending the overall operation timeline, thus maintaining continuous useful action without additional resource consumption.
3Reliability
If the drum is rotated at high speed for tub cleaning, then sterilization effectiveness is improved, but unbalanced vibration occurs when laundry is present
Solution Approach 1:
The patent implements a feedback control system where the MEMS sensor continuously monitors drum vibration during high-speed rotation. When the sensor detects vibration patterns indicating laundry presence, the control unit receives this feedback and automatically adjusts the drum rotation speed to a lower level. This feedback mechanism maintains sterilization effectiveness through initial high-speed rotation while preventing harmful unbalanced vibration through real-time speed adjustment based on sensor input.
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 real-time detection of laundry presence during the tub cleaning cycle, reducing unbalanced vibration and energy use, while diagnosing sensor malfunctions to ensure accurate operation.
Implementation Method 1
measuring displacement data according to vibration of the tub so as to sense whether or not laundry is present in the drum
Implementation Method 2
the supplied water is heated to a set sterilization temperature (a temperature to sterilize microorganisms) by a heater
Data Source
AI summary
A washing machine and a control method thereof in which a tub washing course is safely performed using a sensor to measure vibration of a tub. Since whether or not laundry is present in s drum is sensed while performing the tub washing course, consumption of separate time, water, and energy to sense whether or not laundry is present is not required, and operation of the washing machine is controlled by diagnosing malfunction of the sensor. If plural sensors are installed, a micro-computer is connected to the plural sensors in common through a Serial Peripheral Interface (SPI) communication method or an Inter Integrated circuit (I2C) communication method, thereby reducing costs and volume of wire-harness.