Washing Machine Drum Speed Control Under Unbalanced Load
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Solution Overview
Problem
Existing washing machines face safety risks due to incorrect speed control caused by errors in the algorithm module, which can lead to uncontrolled motor acceleration and vibration issues from unbalanced loads, compromising user safety.
Innovation Solution
The washing machine employs a dual-module control system where the safety module detects unbalanced loads, calculates the maximum safe speed, and compares actual drum speed with this limit, stopping the motor if excessive speed is detected to prevent errors and ensure safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the algorithm module controls the drum speed to reach target speeds required by washing programs, then the washing performance and productivity are improved, but safety risks arise when errors occur in the algorithm module causing uncontrolled motor acceleration
Solution Approach 1:
The control unit is divided into two independent modules: the algorithm module (4) that handles washing program control and speed optimization, and the safety module (5) that independently monitors drum speed and enforces safety limits. This segmentation allows the algorithm module to pursue high productivity goals while the safety module provides independent verification to prevent safety risks from algorithm errors.
Solution Approach 2:
The safety module acts as an intermediary between the algorithm module and the motor execution. It receives speed data from the algorithm module, compares it against independently calculated maximum safe speeds based on unbalanced load detection, and can override algorithm commands to prevent unsafe operation. This intermediary layer ensures that even if the algorithm module contains errors, the motor will not operate beyond safe parameters.
2Productivity
If the drum speed is increased to improve spin-drying efficiency, then the productivity is improved, but vibrations occur due to unbalanced loads compromising safety
Solution Approach 1:
The maximum allowed drum speed is not fixed but dynamically adjusted based on real-time detection of unbalanced load conditions. The safety module continuously monitors vibration levels and modifies the speed limit accordingly, allowing high speeds when loads are balanced (improving spin-drying efficiency) while automatically reducing speeds when unbalanced conditions are detected (preventing harmful vibrations).
Solution Approach 2:
The system implements feedback control where the safety module monitors actual drum speed, unbalanced load conditions, and vibration levels, then adjusts the maximum allowed speed accordingly. This closed-loop feedback ensures that the drum operates at the highest safe speed for each loading condition, optimizing spin-drying efficiency while preventing harmful vibrations from unbalanced loads.
3Reliability
If the safety module independently monitors and controls drum speed, then the safety is improved, but the device complexity increases due to dual-module control system
Solution Approach 1:
The control unit is segmented into two independent modules with clearly defined responsibilities: the algorithm module (4) handles washing program logic and speed optimization, while the safety module (5) handles speed monitoring and safety enforcement. This segmentation improves safety through independent verification while managing complexity by assigning specific, non-overlapping functions to each module, avoiding the need for complex integration logic.
Solution Approach 2:
The safety module is self-sufficient in its safety monitoring function, independently detecting unbalanced loads, calculating maximum safe speeds, and enforcing speed limits without requiring complex coordination with the algorithm module. This self-service capability improves safety while reducing overall system complexity by eliminating the need for complex inter-module communication and coordination protocols.
Data Source
Figure 1
AI summary
The present invention relates to a washing machine (1) comprising a body, a drum (2) wherein the laundry to be washed is disposed and which provides washing and spin-drying by rotating around an axis, a motor (3) which provides the drum (2) to be activated, and a control unit (6) that has a safety module (5) wherein the data such as unbalanced load detection and abnormal condition detection, that relate to safety, are controlled, and an algorithm module (4) wherein the washing, rinsing and spin-drying steps and their durations are controlled.