Washing Drum Child Detection via Pendulum Motion Sensing
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Solution Overview
Problem
Existing household appliances, such as washing machines and dryers, pose a risk of injury or death to children who may enter the drum during operation, with previous methods using water to encourage movement being ineffective and disruptive to the appliance's function, and not suitable for dryers.
Innovation Solution
A method that detects the presence of a child in the drum by controlling the motor to rotate the drum through a specific angle, then evaluating the resulting pendulum movement to determine if a child is present, allowing for safe interruption of the program and potential unlocking of the door to allow the child to exit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water is supplied to encourage the child to move, then the child's movement can be detected, but the laundry is wetted and water is consumed
Solution Approach 1:
The invention extracts the water supply function from the child detection system. Instead of using water to encourage movement, the system uses the drum's existing rotational movement to generate pendulum oscillations that are detected by sensors. This removes the harmful water consumption while maintaining detection capability.
Solution Approach 2:
The invention replaces the hydraulic approach (water supply) with a mechanical oscillation detection approach. The drum's rotational movement creates pendulum oscillations when a child is present, and these mechanical oscillations are detected by sensors, eliminating the need for water-based detection.
2Reliability
If water is supplied to encourage the child to move, then the child's movement can be detected, but the detection method cannot be used in dryers
Solution Approach 1:
The invention creates a universal detection method that works in both washing machines and dryers. By using the drum's rotational movement to generate pendulum oscillations rather than water supply, the system becomes adaptable to different appliance types including dryers where water supply would be inappropriate.
Solution Approach 2:
The invention changes the detection parameter from water-based movement encouragement to mechanical oscillation detection. This parameter change allows the system to function in diverse environments including dryers, washing machines, and potentially other rotating drum appliances.
3Measurement precision
If the drum is rotated through a large angle to detect child presence, then detection sensitivity is improved, but the child may roll over and be injured
Solution Approach 1:
The invention uses partial action by rotating the drum through a limited angle (less than 90 degrees) rather than a full rotation. This partial rotation is sufficient to generate detectable pendulum oscillations when a child is present, while avoiding the excessive action that would cause the child to roll over and be injured.
Solution Approach 2:
The system rushes through the detection process by using the drum's existing rotational movement to quickly generate pendulum oscillations. The detection occurs during the brief oscillation phase rather than requiring sustained large-angle rotation, minimizing the time the child is exposed to potential injury risks.
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 method enhances safety by avoiding water usage, preventing unwanted wetting of laundry, and being applicable to both washing machines and dryers, providing a secure means to recognize and respond to a child's presence without disrupting the appliance's operation.
Implementation Method 1
the drum, with the child that may be in it, begins to make a pendulum movement
Implementation Method 2
the drum, with the child that may be in it, begins to make a pendulum movement
Implementation Method 3
which is dampened over time by friction losses, so that the resting position is restored
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a method for operating a household appliance with a housing (1), a rotatable drum (3) arranged in the housing for receiving laundry, a motor (4) for driving the drum (3), a control device for controlling the motor (4) and an evaluation unit, characterized by the steps carried out after starting a program of the household appliance, controlling the motor (4) by the control unit in such a way that the drum (3) is driven by the motor (4) and by an angle <90° is moved and the motor (4) is switched off when the angle is reached, detecting a speed signal of the drum (3) after the motor (4) is switched off over a predetermined first period of time and evaluating the detected speed signals by the evaluation unit by forming a value, and pausing the program if the value is greater than a predetermined first threshold. The invention also relates to a corresponding household appliance.