Washing Machine Load Imbalance Detection to Prevent Cabinet Strike
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Solution Overview
Problem
Washing machine appliances face issues with unbalanced loads during the spin cycle, leading to undesirable vibrations, noise, and potential damage due to cabinet strikes, which existing solutions fail to predict and prevent effectively, especially at low dwelling speeds during measurement processes.
Innovation Solution
A washing machine system that ramps the motor speed from a first to a second speed, calculates the average deviation and power consumption, and performs a rebalancing process if both exceed specific threshold values, thereby preventing cabinet strikes by identifying and correcting load imbalances before high-speed spin cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drum is rotated at high speeds during spin cycle, then moisture removal efficiency is improved, but cabinet strike events and damage occur due to load imbalance
Solution Approach 1:
The system performs preliminary detection of load balance conditions by measuring motor current and vibration levels before initiating the high-speed spin cycle. If imbalance is detected, the system redistributes the load by rotating the drum at low speed to allow clothes to settle in a balanced configuration, preventing cabinet strikes during subsequent high-speed operation
Solution Approach 2:
The system continuously monitors motor current draw and vibration levels during drum rotation and uses this feedback to detect load imbalance conditions. Based on this real-time feedback, the controller adjusts drum speed and initiates rebalancing procedures when imbalance is detected, preventing cabinet strikes while maintaining efficient spin cycles
2Measurement precision
If the motor operates at low dwelling speeds for measurement, then load detection accuracy is improved, but cabinet strike events may still occur due to persistent load imbalance
Solution Approach 1:
Before performing measurements at low dwelling speeds, the system first rotates the drum at a higher speed to redistribute the load and prevent potential cabinet strikes. This preliminary action ensures that the load is reasonably balanced before the measurement process begins, eliminating the risk of cabinet strikes during low-speed operation
Solution Approach 2:
The system applies preliminary anti-action by detecting potential imbalance conditions through motor current analysis before the measurement process begins and taking corrective action by rotating the drum to redistribute load, thereby preventing cabinet strikes that could occur during the measurement phase
3Object-affected harmful factors
If load rebalancing is performed before spin cycle, then cabinet strike prevention is improved, but cycle time increases due to additional rebalancing process
Solution Approach 1:
The system performs partial rebalancing by rotating the drum only for the minimum necessary duration required to redistribute the load, rather than completing full rebalancing cycles. This partial action is sufficient to prevent cabinet strikes while minimizing the time added to the wash cycle
Solution Approach 2:
The system skips unnecessary rebalancing steps by using motor current analysis to quickly identify and correct only the specific imbalance conditions present, rather than performing complete rebalancing sequences. This allows the system to rush through the essential corrective actions needed to prevent cabinet strikes without adding excessive time to the cycle
Data Source
AI summary
Systems and methods for predicting and preventing a cabinet strike event in a washing machine appliance are provided. An exemplary method includes ramping a target speed of a motor from a first speed to a second speed over a ramping period. The method includes computing an average deviation of an observed speed of the motor from the target speed over the ramping period. The method includes computing an average power consumption by the motor over the ramping period. The method includes determining whether both the average deviation is greater than a first threshold value and the average power consumption is greater than a second threshold value. The method includes rebalancing the load if both the average deviation is greater than a first threshold value and the average power consumption is greater than a second threshold value. The method includes performing one or more standard operations if both conditions are not satisfied.