Laundry Drum Inertia Estimation From Acceleration-to-Plateau Power
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Solution Overview
Problem
Current methods for determining the inertia of a laundry load during the extraction phase in laundry treating appliances result in unnecessarily long cycle times, as they require waiting for a subsequent ramp phase and cannot simultaneously accelerate and maintain speed, leading to increased extraction time.
Innovation Solution
The controller monitors power during the acceleration phase, calculates the power at the transition point to the constant speed phase using curve-fitting methods, and determines the inertia based on the difference in power between the ramp and plateau phases, allowing for earlier determination without needing subsequent ramp data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the conventional method of determining inertia is used (waiting for subsequent ramp phase), then the inertia measurement is accurate, but the cycle time is unnecessarily long
Solution Approach 1:
The patent applies preliminary action by calculating the power at the transition point from acceleration to constant speed phase using curve-fitting methods before the subsequent ramp phase occurs. This allows inertia determination to be performed during the plateau phase rather than waiting for the next ramp, thereby reducing cycle time while maintaining measurement accuracy through mathematical extrapolation of power data.
2Productivity
If the drum is accelerated continuously without plateau phases, then the extraction phase is shorter, but the inertia determination cannot be performed accurately
Solution Approach 1:
The patent performs the inertia measurement during the plateau phase by calculating power at the transition point using curve-fitting on acceleration phase data. This preliminary action eliminates the need to wait for a subsequent ramp phase, allowing the extraction process to proceed more efficiently while still obtaining accurate inertia measurements.
Solution Approach 2:
The patent replaces the conventional mechanical approach of waiting for physical ramp phases with a mathematical substitution method. By using curve-fitting to calculate power at transition points and determining inertia from power differences between acceleration and constant speed phases, the system achieves accurate measurements without requiring additional mechanical cycling.
3Reliability
If multiple plateau and ramp phases are used for inertia determination, then the measurement is more reliable, but the power consumption increases
Solution Approach 1:
The patent substitutes mechanical cycling (multiple ramps and plateaus) with a mathematical calculation approach. By using curve-fitting to determine power at transition points and calculating inertia from the difference between acceleration phase power and constant speed power, the system achieves reliable inertia determination with reduced motor operation time and lower energy consumption.
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 reduces cycle time by enabling inertia determination during the plateau phase, shortening the extraction phase and overall cycle time, and reducing power consumption by minimizing motor operation time.
Implementation Method 1
a motor rotatably driving the drum in response to a motor control signal
Implementation Method 2
a drum holding the laundry rotates at speeds high enough to impart a sufficient centrifugal force on the laundry load to remove the liquid
Data Source
AI summary
A laundry treating appliance for treating a laundry load according to at least one cycle of operation including a rotatable drum at least partially defining a treating chamber in which a laundry load is received for treatment, a motor rotatably driving the drum in response to a motor control signal, and a controller outputting a motor control signal to rotate the drum according to a speed profile having at least a constant speed phase, where the drum is rotated at a constant speed, and an acceleration phase, where the drum is accelerated to the constant speed and a method of operating a laundry treating appliance to determine an inertia of the laundry load.