Laundry Dryer Load Estimation Using Motor Torque Variation Sensing
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Solution Overview
Problem
Current laundry drying machines lack an efficient method to estimate laundry load, which hinders optimal drying cycle optimization and energy consumption adjustment.
Innovation Solution
A rotatable-drum laundry drying machine equipped with an electronic control system that utilizes a sensing device to measure torque changes over time, correlating these changes with laundry load, allowing for accurate estimation and optimization of drying cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If no torque sensing device is installed, then the device complexity is reduced, but the measurement precision of laundry load is insufficient
Solution Approach 1:
The motor assembly serves dual functions: both driving the drum rotation and sensing the torque through its own operational parameters. The control unit monitors existing motor current and power consumption data to infer torque, eliminating the need for separate sensing devices while maintaining measurement capability.
Solution Approach 2:
The motor assembly is designed to perform multiple functions simultaneously: it acts as both the actuator for drum rotation and the sensor for torque measurement. By utilizing the motor's inherent electrical characteristics (current draw, power consumption) to indicate torque levels, the system achieves load measurement without adding dedicated sensing components.
2Measurement precision
If torque sensing is implemented, then the measurement precision of laundry load is improved, but the device complexity increases
Solution Approach 1:
The system replaces direct mechanical torque sensing with electrical parameter monitoring. Instead of using mechanical strain gauges or torque sensors on the drive shaft, the control unit measures electrical quantities (current, power) that correlate with torque demand, substituting a simpler electrical measurement system for a complex mechanical sensing system.
Solution Approach 2:
The control unit acts as an intermediary that translates electrical motor parameters into torque information. By monitoring the relationship between motor power, current, and drum speed, the control unit calculates torque as an intermediate value that reflects the laundry load, avoiding direct mechanical coupling between the sensor and drive mechanism.
3Productivity
If laundry load estimation is inaccurate, then the productivity of drying cycle is reduced, but adding complex sensing systems increases device complexity
Solution Approach 1:
The control unit continuously monitors motor electrical parameters during the drying cycle and uses this feedback to estimate torque and infer laundry load. This real-time feedback mechanism allows the system to adapt to changing load conditions and optimize drying parameters without requiring complex pre-installation sensing systems.
Solution Approach 2:
The system monitors changes in motor operational parameters (current, power consumption) that correspond to changes in laundry load. By tracking these parameter variations throughout the drying cycle, the system dynamically estimates load conditions and adjusts drying efficiency accordingly, using simple parameter monitoring rather than complex 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
Enables precise estimation of laundry load, optimizing drying cycle time and energy consumption, leading to improved efficiency and performance.
Implementation Method 1
an electronic control unit configured to: receive a sensed signal which is indicative of a torque that a motor assembly provides to the rotatable laundry drum; determine a value of a parameter which is indicative of a variation of the sensed signal in time; and estimate the laundry-load based on the determined value of the parameter
Data Source
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AI summary
Laundry drying machine (1) comprising a rotatable laundry drum (3) designed to rotate about an axis of rotation (6), an electric motor (9) which is mechanically connected with the rotatable laundry drum (3) for rotating said rotatable laundry drum (3) about its axis of rotation (6); hot-air generator means (11) configured to supply a heated airflow to the drum (3) during a drying cycle; and an electronic control system (16) configured to provide a sensed signal (S1) which is indicative of a torque that said electric motor (9) provides to the rotatable laundry drum (3); determine the value of a parameter (ΔS1, TIME) that is indicative of variation of the sensed signal (S1) in time, and estimate the laundry-load contained within said chamber (4) based on said determined value of said parameter (ΔS1, TIME).