Wash article entrapment detection for laundry washing machines
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Solution Overview
Problem
Laundry washing machines face challenges in detecting articles trapped between the drum door and bellows seal, leading to potential damage during high-speed spinning phases, as conventional methods often fail to identify entrapment early enough to prevent damage.
Innovation Solution
A method involving the washing machine's drum motor acceleration to a target rotation speed, followed by a series of rotations to determine torque values and distribution characteristics, allowing for early detection of entrapment and subsequent correction operations to address the issue before high-speed spinning begins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If entrapment detection is performed during high-speed dynamic imbalance measurement phase, then detection capability is improved, but damage may already have occurred by this point
Solution Approach 1:
The patent applies preliminary action by performing entrapment detection during the initial low-speed phases of the washing cycle, before high-speed spinning begins. The system monitors drum motor torque characteristics during slow drum movement and inertia pre-estimation phases to identify entrapped articles early, preventing damage that would occur during subsequent high-speed rotation.
2Productivity
If drum rotates at high speed for water extraction, then washing efficiency is improved, but forces on entrapped articles increase causing damage
Solution Approach 1:
The patent applies preliminary anti-action by implementing corrective operations during low-speed phases to remove or reposition entrapped articles before high-speed spinning begins. The system performs correction operations such as pausing the drum, reversing rotation, or alerting the user to remove the obstruction, thereby preventing the harmful forces that would occur during high-speed water extraction.
3Reliability
If entrapment detection is performed during initial low-speed phases, then damage prevention is improved, but detection difficulty increases
Solution Approach 1:
The patent applies feedback by continuously monitoring drum motor torque characteristics during initial low-speed phases and comparing them against expected values. The system uses feedback from torque measurements during inertia pre-estimation and load distribution evaluation to identify anomalies indicating entrapped articles, enabling early detection despite the challenging low-speed conditions.
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 enables the detection of trapped articles at the beginning of the wash cycle, preventing damage by allowing for corrective actions before the high-speed spinning phase, thus ensuring proper operation and reducing repair costs.
Implementation Method 1
operating the drum motor to accelerate the drum to a target rotation speed
Implementation Method 2
performing a first plurality of rotations at the target rotation speed
Data Source
AI summary
A method for detecting entrapment of an article within a laundry washing machine. The method includes rotating the drum to a target rotation speed, determining a respective drum motor torque value for each rotation, determining a distribution characteristic value of the drum motor torque values, comparing the distribution characteristic value to a predetermined threshold value, performing a correction operation to address an entrapment condition upon determining that the distribution characteristic value is above the predetermined threshold value, and proceeding with the laundry washing cycle upon determining that the distribution characteristic value is below the predetermined threshold value.