Washer Drum Imbalance Detection Using Motor Torque Feedback
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Solution Overview
Problem
Laundry treating appliances experience undesirable vibrations and movements due to load imbalances during drum rotation, which can lead to inefficient operation and potential damage.
Innovation Solution
A method and apparatus that continuously monitor the motor torque to determine the peak-to-peak values, calculate the average peak-to-peak value, assess the load imbalance, and take corrective action when the imbalance exceeds a threshold, using a controller and sensors to adjust the drum speed and redistribute the laundry load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drum is rotated at high spin speeds to improve productivity, then the laundry treating cycle is completed faster, but load imbalance causes undesirable vibrations and movements that reduce reliability
Solution Approach 1:
The system performs preliminary detection of load imbalance before high-speed rotation begins by monitoring motor torque during drum rotation. The controller identifies imbalance conditions early and redistributes the laundry load by adjusting drum speed or direction, preventing vibrations before they occur during high-speed operation.
Solution Approach 2:
The system continuously monitors motor torque during drum rotation and uses this feedback to detect load imbalance. The controller processes the torque signal to determine imbalance magnitude and implements corrective actions by adjusting motor operation to redistribute the laundry, maintaining stability during high-speed rotation.
2Reliability
If load imbalance is detected and corrective action is taken to reduce vibrations, then operational reliability is improved, but the treatment time is extended
Solution Approach 1:
The system applies partial corrective action by redistributing only the imbalanced portion of the laundry load rather than stopping the entire cycle. The controller adjusts motor torque to move laundry items gradually, correcting imbalance during ongoing rotation rather than requiring a complete cycle interruption.
Solution Approach 2:
The laundry treatment process continues uninterrupted while corrective action is applied. The drum maintains rotation throughout the imbalance correction process, allowing the useful treatment action to continue while the controller redistributes the load to eliminate vibrations.
3Measurement precision
If motor torque is continuously monitored to detect load imbalance, then measurement precision is improved, but device complexity increases due to additional sensors and control circuitry
Solution Approach 1:
The motor itself serves as the sensing element by providing torque information that indicates load imbalance. The existing motor structure and electrical characteristics are utilized to detect imbalance conditions without requiring separate dedicated sensors, allowing the motor to perform both its driving function and the sensing function.
Solution Approach 2:
The motor performs multiple functions: it provides the mechanical driving force for drum rotation and simultaneously serves as the sensing element for detecting load imbalance through its torque characteristics. The controller integrates both motor control and imbalance detection functions into a single control system.
Data Source
AI summary
A laundry treating appliance for treating a laundry load according to at least one cycle of operation and a method of operating a laundry treating appliance to determine an amount of imbalance of the laundry load in the drum based on a determined average peak-to-peak value and taking corrective action when the determined amount of imbalance does not satisfy a threshold.