Washer Dryer Motor Current Sensing During Preliminary Drum Rotation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional laundry amount measurement methods in washer dryer machines are inadequate in ensuring safety, particularly when a child is inside the drum, as they may rotate at high speeds, potentially harming the child, and require additional costly components like weight sensors for accurate detection.
Innovation Solution
A washer dryer machine with a controller that measures the electric current of the motor to detect foreign objects by rotating the drum less than one turn, stopping the operation if a foreign object is detected, without the need for additional components like weight sensors, thus ensuring safety and accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the drum rotates at high speed to measure laundry amount accurately, then measurement accuracy is improved, but safety deteriorates when a foreign object is inside the drum
Solution Approach 1:
The system performs a preliminary detection by rotating the drum less than one turn at a low rotation speed before the main laundry amount measurement. This preliminary action detects the presence of foreign objects using electric current measurement, preventing high-speed rotation when foreign objects are present, thus resolving the contradiction between measurement accuracy and safety.
2Measurement precision
If additional components like weight sensors are added to detect foreign objects accurately, then detection accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The motor serving the drum rotation is made to perform dual functions: both driving the drum for laundry amount measurement and detecting foreign objects through electric current measurement during the preliminary low-speed rotation. This eliminates the need for separate weight sensors or additional detection components, resolving the contradiction between detection accuracy and device complexity.
Solution Approach 2:
The system uses its own motor's electric current characteristics to detect foreign objects, rather than requiring external detection devices. The motor self-provides the detection capability through monitoring its own current consumption during preliminary rotation, simplifying the overall system structure.
3Object-affected harmful factors
If the drum rotates at low speed to ensure safety, then safety is improved, but measurement accuracy deteriorates
Solution Approach 1:
The system first performs a safety check by rotating the drum less than one turn at low speed to detect foreign objects. Only after confirming no foreign objects are present does the system proceed to the main laundry amount measurement at appropriate rotation speeds, thus ensuring both safety and measurement accuracy.
Solution Approach 2:
The system uses feedback from electric current measurement during preliminary low-speed rotation to determine whether to proceed with high-speed measurement. If the current indicates a foreign object is present, the system aborts the measurement process, thereby maintaining safety while preserving measurement accuracy when conditions are appropriate.
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
The solution effectively prevents operation when a foreign object, such as a child, is inside the drum, enhancing safety and eliminating the need for costly additional components, while allowing for accurate laundry amount detection.
Implementation Method 1
a motor that rotationally drives the drum
Data Source
AI summary
A washing machine includes: a drum that rotates with a washing or drying object contained in the drum; a motor that rotationally drives the drum; a controller that controls rotation of the motor; and an electric current measurer that measures an electric current value representing an electric current flowing in the motor. The controller controls the rotation of the motor to rotate the drum less than one turn, and in accordance with the measured electric current value, detects whether a foreign object that is different from the object and whose mass is greater than an expected mass of the object is inside the drum. In a case where the controller detects the foreign object, the controller stops operation of the washing machine.