Laundry Drum Load Sensing Using Dual Displacement and Tilt Detection
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Solution Overview
Problem
Existing methods for determining laundry mass in washing machines are inaccurate due to static friction in shock absorbers, leading to incorrect load calculations during the washing process.
Innovation Solution
The method involves using independent physical means to record the path and inclination of the oscillating system, allowing for precise calculation of laundry mass by distinguishing between weight-induced lowering and external influences, and incorporating acceleration sensors to correct for static friction errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If displacement sensors are used to detect the lowering of the oscillation system, then load measurement is enabled, but static friction in shock absorbers causes inaccurate measurements
Solution Approach 1:
The patent combines displacement sensors and acceleration sensors into an integrated measurement system. The displacement sensor detects vertical lowering of the oscillation system, while the acceleration sensor detects inclination and external vibrations. By merging these sensor inputs, the system achieves accurate load measurement that compensates for static friction effects in the shock absorbers.
Solution Approach 2:
The system uses feedback from both displacement and acceleration sensors to continuously monitor and correct for static friction effects. The acceleration sensor detects when the oscillation system is tilted or subjected to external forces, and this information feeds back to the control unit to adjust the load calculation, thereby maintaining measurement reliability despite static friction in the shock absorbers.
2Device complexity
If only displacement sensors are used, then the system structure is simple, but external influences cannot be distinguished from weight-induced lowering
Solution Approach 1:
The acceleration sensor acts as an intermediary that detects external influences such as vibrations and tilts. By introducing this intermediary sensor, the system can distinguish between load-induced displacement and external disturbances, thereby improving measurement precision without significantly increasing overall system complexity.
3Measurement precision
If acceleration sensors are added to detect inclination, then load measurement precision is improved, but device complexity increases
Solution Approach 1:
The acceleration sensor serves multiple functions: it detects inclination for accurate load measurement, identifies external vibrations, monitors the oscillation system's rest position, and detects asymmetrical loading conditions. By making the sensor system multi-functional, the patent improves measurement precision for various scenarios without proportionally increasing device complexity.
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 provides more accurate load calculations compared to prior methods, reducing errors caused by static friction and offering higher precision with minimal additional effort, especially when considering asymmetrical loading conditions.
Implementation Method 1
a device for detecting the displacement of the container system relative to the housing
Implementation Method 2
the direction and angle of an inclination of the oscillating system relative to its normal position in the rest position are recorded
Implementation Method 3
an oscillating system made of a carrier which is resiliently supported in a housing
Implementation Method 4
washing machines are equipped with damping elements, preferably friction shock absorbers
Data Source
Figure 1~6
AI summary
The invention relates to a method for determining the laundry mass as laundry is introduced into a laundry treatment machine, in particular a washing machine, a washer-dryer, or a laundry dryer, comprising a vibrational system (2), which is resiliently supported in a housing (1) at at least two points arranged in a distributed manner with respect to the vertical line passing through the center of gravity and which consists of a support and a laundry drum supported therein, and comprising a device (6, 7, 13) for sensing the displacement of the vibrational system (2) in relation to the housing (1). The problem addressed by the invention is that of sensing of the lowering of the vibrational system from the resting location in dependence on the weight of the introduced laundry items in a more precise manner compared to methods known from the prior art and making the sensing more distinguishable from external influences. This problem is solved, according to the invention, in that the distance of a lowering of the vibrational system (2) from the resting position and the direction x or y and the angle α or ß of a tilting of the vibrational system (2) in relation to the normal situation of the vibrational system in the resting position are sensed by means of physical means that are independent of each other and the sensed deviations of the lowering and of the tilting are jointly used to calculate the introduced mass.