Laundry Drum Balance Ring Control for Tub-Contact Prevention
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Solution Overview
Problem
Existing balance rings in horizontal axis washing machines fail to effectively counteract load imbalances at low speeds and during rotational acceleration, leading to potential contact between the drum and tub, which can cause damage and noise.
Innovation Solution
A method and apparatus that utilize a balance ring with movable masses to estimate the relative position of the load imbalance and adjust the drum's rotation speed by determining the torque, acceleration, and angular position, allowing for optimal phasing with the load to prevent contact during acceleration from low to high speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a balance ring with movable masses is used to counteract load imbalances, then the stability of the drum rotation is improved, but the device complexity increases due to the need for sensors and control systems to determine torque, acceleration, and angular position
Solution Approach 1:
The system performs preliminary measurement during a measurement period to determine the angular positions of the load imbalance and balance masses before the main operation. This allows the control system to pre-calculate the optimal acceleration timing, avoiding the need for complex real-time adjustments during high-speed rotation.
Solution Approach 2:
The system uses sensors to continuously monitor torque, acceleration, and angular position of the drum, feeding this information back to the controller. The controller then adjusts the motor acceleration based on this feedback to maintain optimal phasing between balance masses and load imbalance, improving stability while managing complexity through intelligent control.
2Productivity
If the drum accelerates from low to high speed during operation, then the productivity of the laundry treating process is improved, but the likelihood of tub-container contact increases due to load imbalance at low speeds
Solution Approach 1:
The system performs a measurement period during low-speed rotation to determine the angular positions of the load imbalance and balance masses before acceleration. This preliminary information allows the controller to plan the acceleration trajectory to maintain optimal phasing, preventing tub-container contact while enabling high-speed operation for productivity.
Solution Approach 2:
The system dynamically adjusts the acceleration profile based on the real-time positions of the load imbalance and balance masses. By making the acceleration dynamic rather than fixed, the system can optimize the timing and rate of speed increase to maintain stability throughout the transition from low to high speed, avoiding contact while achieving productivity goals.
3Volume of moving object
If the drum size is increased to improve laundry treating capacity, then the volume of laundry that can be treated is improved, but the appliance size must increase unless the drum can be optimized for compact operation
Solution Approach 1:
The system changes operational parameters (acceleration rate, rotational speed, phasing) to optimize the performance of a given drum size. By carefully controlling these parameters, the system can achieve effective laundry treating in a compact appliance configuration, as the optimized operation allows smaller drums to perform as effectively as larger ones would without the balance control system.
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 solution reduces the likelihood of tub-container contact, extends the appliance's lifespan, and allows for a larger drum size without increasing the appliance's size, by optimizing the phase difference between the balance balls and the load mass during the ramping process.
Implementation Method 1
at least one balance ring mounted to the drum and defining an internal annular cavity in which a mass is located
Data Source
AI summary
Methods of reducing a likelihood of contact between a rotating laundry-container, such as a basket or drum, located within a tub of a laundry treating appliance where the method includes rotating the drum during a measurement period, determining a torque, speed, acceleration, and position of the drum, using a parameter estimator to estimate the position of a mass relative to an imbalance of laundry and accelerating the rotation of the drum when the mass is determined to be angularly spaced from the relative position of the imbalance of laundry.