Washer Drum Speed Ramp Control for Tub Contact Prevention
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Solution Overview
Problem
Existing laundry treating appliances face challenges in accurately preventing contact between the rotating laundry-container and the tub during high-speed operations, as existing methods rely on off-balance estimation or torque monitoring, which are inaccurate and prone to sudden failures.
Innovation Solution
The method involves accelerating the rotational speed of the laundry-container during an extraction cycle speed ramp, monitoring friction, comparing it to a threshold value correlated to the gap size, and altering the acceleration when the threshold is met to reduce the likelihood of container-tub contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotational speed of the laundry-container is increased during extraction cycle, then productivity is improved, but the likelihood of container-tub contact increases causing damage
Solution Approach 1:
The system continuously monitors friction during the speed ramp and uses this feedback to detect when the container is approaching contact with the tub. When friction exceeds a threshold, the system responds by altering the acceleration rate, creating a closed-loop control system that prevents contact while enabling high-speed operation.
Solution Approach 2:
The patent implements dynamic adjustment of the acceleration rate based on real-time friction conditions. Rather than using a fixed acceleration profile, the system adapts the ramp characteristics during operation, reducing acceleration when friction indicates impending contact and allowing faster ramps when conditions permit, thereby optimizing both productivity and reliability.
2Reliability
If friction monitoring is implemented to prevent container-tub contact, then reliability is improved, but device complexity increases
Solution Approach 1:
The system uses the existing motor's electrical characteristics to self-diagnose friction conditions. By monitoring parameters already available from the motor controller (current, voltage, speed), the system derives friction information without requiring separate sensors or measurement devices, thereby improving reliability while minimizing additional complexity.
Solution Approach 2:
The patent replaces potential mechanical friction sensors or contact detection devices with an electrical/electronic monitoring approach. By using the motor's electrical signature to infer mechanical friction conditions, the system achieves accurate contact detection through software-based friction calculation rather than additional mechanical sensing hardware.
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 effectively reduces the risk of container-tub contact, allowing for higher spinning speeds without damage, improving cycle time and product life, and providing more accurate and precise control compared to existing solutions.
Implementation Method 1
a motor operably coupled with the rotating laundry-container and configured to rotatably drive the rotating laundry-container in response to a motor control signal
Implementation Method 2
monitoring the friction associated with the rotating laundry-container during the speed ramp
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 accelerating a rotational speed of the rotating laundry-container during an extraction cycle speed ramp, monitoring the friction associated with the rotating laundry-container during the speed ramp and comparing to a threshold and altering the accelerating of the rotational speed of the rotating laundry-container when the comparing indicates the threshold is satisfied.