Control method of laundry treating apparatus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional laundry treating apparatuses fail to accurately determine the location and size of unbalanced masses in the drum, leading to increased noise and vibration during high-speed spinning cycles, as existing unbalance sensing methods are prone to errors when masses are distributed asymmetrically.
Innovation Solution
A control method that includes measuring phase differences and displacements of the tub surfaces to determine the angle and size of unbalanced masses in the front and rear areas of the drum, allowing for precise adjustment of rotational speed and acceleration based on allowable mass and angle ranges to maintain dynamic balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional unbalance sensing method detecting sum of centrifugal force vectors is used, then the sensing process is simple, but the determination precision of UB mass location and size is poor
Solution Approach 1:
The patent divides the single unbalance mass detection into two separate detection zones: front unbalance mass (fUB) detection and rear unbalance mass (rUB) detection. By measuring displacements at both front and rear tub surfaces independently, the system segments the measurement task to achieve more precise location and size determination of unbalance masses, resolving the limitation of conventional single-point sensing.
Solution Approach 2:
The patent transitions from single-dimensional (single measurement point) unbalance detection to two-dimensional detection by incorporating measurements from both front and rear tub surfaces. This dimensional expansion enables the system to determine not only the magnitude but also the precise angular position and distribution of unbalance masses around the drum circumference.
2Productivity
If drum rotation is allowed at high rotational speed based on conventional unbalance sensing, then productivity is improved, but noise and vibration increase due to inaccurate unbalance determination
Solution Approach 1:
The system uses displacement sensors to continuously monitor tub surface displacements at front and rear positions, feeds this information back to the controller, which then determines unbalance mass characteristics and adjusts drum rotation accordingly. This feedback mechanism enables the drum to rotate at high speeds only when unbalance is within acceptable limits, preventing excessive noise and vibration while maintaining productivity.
3Reliability
If conventional unbalance sensing method is used, then the control process is simple, but the reliability of high-speed drum operation is poor
Solution Approach 1:
The control process is segmented into distinct evaluation stages: front unbalance mass determination, rear unbalance mass determination, and combined evaluation for high-speed rotation permission. This segmentation improves reliability by systematically checking multiple unbalance parameters before allowing high-speed operation, rather than relying on a single simplified measurement.
Solution Approach 2:
The system performs preliminary unbalance detection and evaluation at lower rotational speeds before permitting high-speed drum rotation. By conducting front and rear unbalance mass determination in advance and comparing against threshold values, the system ensures reliable high-speed operation conditions are met before increasing productivity.
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 accurate determination of unbalanced masses and their locations, reducing noise and vibration by ensuring the drum operates within acceptable vibration ranges, even at high rotational speeds, thereby improving the efficiency and reliability of the laundry treating process.
Implementation Method 1
measuring a phase difference between the two maximum displacements... measuring a displacement of a tub front surface and a displacement of a tub rear surface
Implementation Method 2
the rotational speed of the drum rotating in the unbalance state is the highest when the UB mass passes the lowermost point of a drum rotation locus and the lowest when the UB mass or the laundry causing the unbalance passes the uppermost point
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
The present disclosure relates to a control method of a laundry treating apparatus comprising a tub defining a predetermined space for storing water and having a tub opening formed in a front surface; a drum rotatably provided in the tub and configured to hold laundry; and a sensing unit configured to sense three-shaft acceleration and three-angle angle velocity, the control method comprising: a maintaining step for rotating the drum at a reference rotational speed that is set to be a lower or a higher rotation than a rotational speed causing resonance in the laundry treating apparatus; a measuring step for controlling the sensing unit to measure the maximum displacement of a tub front surface, the maximum displacement of a tub rear surface and a phase difference between the maximum displacements during the rotation of the drum at the reference rotational speed; a determining step for determining a front UB mass located in a drum front area, a rear UB mass located in a drum rear area and an angle between the UB masses based on the maximum displacement of the tub front surface, the maximum displacement of the tub rear surface and the phase difference between the maxim displacements; and an accelerating step for accelerating the drum rotational speed to a target rotational speed that is set to be higher than the reference rotational speed and the rotational speed causing resonance, when the front UB mass and the rear UB mass are in a preset allowable mass range and an angle between the two UB masses is in an allowable angle range.