Inertial Measurement Unit for Domestic Appliance Door Angle Detection

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Solution Overview

Problem

Conventional door monitoring systems for domestic appliances face challenges in accurately detecting the opening angle and speed due to sensor placement issues, particularly in high-temperature areas, leading to reduced accuracy.

Innovation Solution

The use of an inertial measurement unit (IMU) comprising an accelerometer and/or gyroscope, arranged at optimal positions away from the hinge axis and in low-temperature areas, such as within the door handle or front panel, to determine the angle, angular speed, and angular acceleration with improved precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensors are arranged at the door hinge or close to the door hinge, then the door opening angle can be detected, but the measurement accuracy deteriorates due to difficult detection of exact opening angle

Engineering Contradiction:

Improvedoor opening angle detection accuracyVSAvoidsensor arrangement complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor is extracted from the door hinge area and relocated to the door handle area, separating the measurement function from the problematic hinge region. This allows accurate detection of door opening angle without the complexity of hinge-mounted sensor arrangements.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The door handle serves as an intermediary structure that facilitates accurate angle detection. By mounting the sensor on the door handle rather than directly at the hinge, the system achieves better measurement accuracy while simplifying the overall arrangement.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If sensors are arranged in positions where the temperature is very high, then the door state can be detected, but the measurement accuracy deteriorates due to temperature impairment

Engineering Contradiction:

Improvesensor measurement accuracyVSAvoidsensor operating temperature

Core Design Contradiction:

Measurement precisionVSTemperature

Solution Approach 1:

The sensor is extracted from high-temperature regions near the hinge and relocated to the door handle area, which operates at lower temperatures. This separation removes the harmful thermal environment from the sensor while maintaining detection functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Different regions of the door assembly have different thermal characteristics. The invention places the sensor in the locally cooler door handle region rather than the hotter hinge region, optimizing sensor operating conditions for accurate measurement.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If classical mechanical door switches are used, then the door state can be detected, but measurement errors occur due to assembly-related tolerances

Engineering Contradiction:

Improvedoor state detection accuracyVSAvoidassembly tolerance sensitivity

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The invention replaces classical mechanical door switches with an inertial measurement unit (IMU) that uses accelerometers and/or gyroscopes. This substitution eliminates mechanical contact and assembly tolerance issues, providing more accurate and reliable door state detection through inertial sensing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution enhances the accuracy and reliability of door state detection, allowing for precise control of opening and closing speeds, reducing measurement errors, and eliminating the need for classical mechanical door switches with their assembly-related tolerances.

Implementation Method 1

the accelerometer can be provided for detecting a linear acceleration of the door sensor

Methodology Applied

Scientific EffectAccelerometer: Accelerometer

Implementation Method 2

the gyroscope can be provided for detecting a rotational speed of the door sensor

Methodology Applied

Scientific EffectGyroscope: Gyroscope

Data Source

PatentUS12158037B2Monitoring system for a door of a domestic appliance and domestic appliance comprising such a system

Publication Date: 2024.12.03 ELECTROLUX APPLIANCES

AI summary

The present disclosure relates to a monitoring system for a door (12) of a domestic appliance (10). The monitoring system comprises at least one door sensor (22; 24, 26, 28; 30, 32) arrangeable or arranged at or within the door (12). The door sensor (22; 24, 26, 28; 30, 32) is an inertial measurement unit (IMU) including at least one accelerometer and/or at least one gyroscope. The accelerometer can be provided for detecting a linear acceleration of the door sensor (22; 24, 26, 28; 30, 32). The gyroscope can be provided for detecting a rotational speed of the door sensor (22; 24, 26, 28; 30, 32). The monitoring system determines at least one of the angle (α,α′), the angular speed and the angular acceleration of the door (12).