Laundry Cycle Timing Control for User-Set Finish Time

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Solution Overview

Problem

Laundry treating machines, such as washing and drying machines, often fail to complete a selected course at the user-set finish-in or finish-at time due to variability in washing and drying phases, leading to inconsistencies in completion time.

Innovation Solution

A laundry treating machine with a controller that monitors the actual duration of each phase and adjusts the duration of subsequent phases to ensure the course ends at the user-set end time, by calculating time differences and compensating for variations in spin and rinse phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the controller starts the laundry treating course based on the nominal duration and user-set finish time, then the course can be scheduled to end at the desired time, but the actual completion time deviates from the set finish time due to phase duration variability

Engineering Contradiction:
Improvetime deviation from finish-at/finish-in timeVSAvoidcompletion time accuracy
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The controller performs preliminary actions by monitoring the actual duration of each phase as it executes and proactively calculating the cumulative time deviation from the nominal duration. Based on this preliminary monitoring, the controller determines compensatory time adjustments needed for subsequent phases before the course ends, ensuring the final completion time matches the user-set finish time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The controller implements a feedback mechanism by continuously monitoring the actual duration of each laundry treating phase, comparing it with the nominal duration, and using this information to dynamically adjust the duration of subsequent phases. This closed-loop control ensures that cumulative time deviations are corrected, guaranteeing the course ends at the precisely scheduled finish time.

Inventive Principle:
Principle #23Feedback

2Reliability

If the duration of laundry treating phases is adjusted dynamically to compensate for time deviations, then the course can end at the exact finish time, but the control system becomes more complex

Engineering Contradiction:
Improvecompletion time accuracyVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The controller applies segmentation by dividing the laundry treating course into discrete phases and monitoring each phase's actual duration independently. For each phase, the controller calculates the time deviation from its nominal duration and determines the corresponding compensatory adjustment for the next phase. This segmented approach simplifies the control logic compared to monitoring the entire course as a single unit, making the system easier to implement and maintain.

Inventive Principle:
Principle #1Segmentation

3Reliability

If spin phases include multiple balance attempts and redistribution phases to reduce unbalance, then the spin effectiveness improves, but the spin phase duration varies significantly

Engineering Contradiction:
Improvespin balance effectivenessVSAvoidspin phase duration variability
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The controller uses feedback by monitoring the actual duration of the spin phase, including all balance attempts and redistribution phases. The cumulative time deviation generated by these necessary balance operations is fed back to the controller, which then calculates and applies compensatory time adjustments to subsequent rinse or spin phases, ensuring the overall course duration remains on schedule despite spin phase variability.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2876194B1Laundry treating machine and method for control thereof
Publication Date: 2016.09.21 ELECTROLUX APPLIANCES
  • EP2876194B1 patent drawingFigure 1
  • EP2876194B1 patent drawingFigure 2~3
  • EP2876194B1 patent drawingFigure 4

AI summary

The present invention relates to a laundry treating machine (1) comprising an outer casing (2), a rotatable drum (3), which is arranged in axially rotating manner inside the outer casing (2) and is structured to receive the laundry to be treated, a laundry treating course select unit (7) provided for an operator to select a laundry treating course to be performed; laundry treating course having a nominal total course duration (tn), and comprising a plurality of laundry treating phases/steps, each having a nominal duration (tc(i), tp(i)); a time input unit (8) provided for an operator to input an end-time value (tu), which is indicative of a time at which, or in which, the laundry treating course has to be ended; a start input unit (9) provided for an operator to input a course start command; a controller (5) configured to automatically start performing a selected laundry treating course based on a inputted course start command and an inputted end-time value (tu); during the execution of said laundry treating course, determine a treating phase time information which is related to actual duration (ta(i)) which a monitored laundry treating phase/step (i) spent to be completed, vary, with respect to its nominal value (tc(i), tp(i)), the duration of laundry treating phases/steps (i+1) to be performed following the monitored laundry treating phase/step (i), based on the determined treating phases/steps time information, in such a way to cause the laundry treating course to end at/in said end-time value (tu) set by operator.