Laundry Load Sensing Using 3D Drum Suspension Displacement
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Solution Overview
Problem
Existing laundry treatment appliances, such as washing machines, struggle to accurately determine the weight of a laundry load due to uneven loading, which causes tilting and results in imprecise weight measurement, especially when only detecting displacement in one direction, leading to inaccurate load quantification and restricted sensor arrangement.
Innovation Solution
The method involves detecting displacement of the container system in three perpendicular directions to account for inclination and center of gravity, using commercially available 3-axis sensors to calculate load quantity through a polynomial formula, and adjusting for geometric and spring-related factors, allowing for precise load determination and optimal wash program control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If displacement is detected in only one direction, then the sensor arrangement is simple, but the load weight determination becomes imprecise due to container tilting
Solution Approach 1:
The patent transitions from single-direction displacement detection to three-dimensional displacement detection by adding sensors in multiple directions (x, y, and z axes). This dimensional expansion allows the system to capture container tilting movements that occur when laundry is unevenly distributed, thereby maintaining measurement precision without excessive complexity increase.
Solution Approach 2:
The displacement sensors are designed to serve multiple functions: detecting vertical displacement for load weight measurement, detecting horizontal displacement for container tilting detection, and providing data for both load quantity determination and load distribution analysis. This multi-functionality reduces the need for separate sensing systems.
2Ease of operation
If the container system is resiliently supported to allow movement, then the displacement detection works, but the container may tilt asymmetrically causing measurement errors
Solution Approach 1:
The patent converts the harmful effect of container tilting (caused by resilient support) into a useful measurement signal. By equipping the system with three-axis displacement sensors, the tilting movements that were previously sources of measurement error become informative data about load distribution, allowing the system to compensate for asymmetry and improve overall measurement accuracy.
Solution Approach 2:
The system uses displacement sensor data to provide feedback about container position and tilting. This feedback enables the control unit to calculate corrective factors that compensate for asymmetric load distribution, thereby maintaining accurate load weight determination despite the container's resilient support and potential tilting.
3Measurement precision
If multiple displacement sensors are arranged in different directions, then tilting can be detected, but the device complexity increases
Solution Approach 1:
The patent merges multiple single-axis displacement sensors into a three-axis sensor system that can detect movements in x, y, and z directions simultaneously. This consolidation reduces the number of separate sensor components needed while maintaining the capability to detect container tilting and vertical displacement for accurate load weight determination.
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 precise load quantification, reducing measurement errors and energy usage by accurately determining load weight and residual moisture content, allowing for optimized wash cycles and efficient resource utilization.
Implementation Method 1
one or more spring elements which connect the housing to a container system
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
The invention relates to a method of determining a loading quantity (m) for a laundry-treatment appliance, in particular a washing machine, a washer drier or a tumble drier, having a container system which is supported resiliently in a housing (1) and in which is arranged a drum (8) for accommodating the load (7), and having a device (2) for detecting displacement of the container system in relation to the housing (1), comprising the following steps: detecting displacement (z1) of the container system in relation to the housing (1) in a first direction (z), detecting displacement (y1) of the container system in relation to the housing (1) in at least a second direction (x, y), which differs from the first direction (z), and determining the loading quantity (m) in dependence on the displacement (y1, z1) detected in the first and second directions (y, z). The invention also relates to a laundry-treatment appliance which is suitable for implementing the method.