Method for determining a door opening request, sensor facility for this purpose and household appliance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing household appliances without door handles require users to press against the door to open it, which can be unreliable and inconvenient, especially for users with visual impairments or in dark environments, due to the limited actuation area and potential for misalignment.
Innovation Solution
A method and sensor facility that utilize a rotating electric machine and plunger mechanism to detect pressure actuations on the door's outer face by inducing a voltage in the stator winding, which is then evaluated for amplitude and duration to determine a valid door opening request.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a sensor facility with a limited actuation area is used to detect door opening requests, then the device complexity is reduced, but the ease of operation deteriorates because users must precisely target the sensor area
Solution Approach 1:
The stator winding of the rotating electric machine is given dual functionality: it serves both as an electromagnetic component for door opening and as a sensor facility for detecting door opening requests. When voltage is applied, it acts as a motor; when voltage is not applied, it detects pressure actuations as induced voltages. This eliminates the need for separate sensor facilities, reducing device complexity while providing a large detection area across the entire door inner face.
Solution Approach 2:
The rotating electric machine's stator winding serves itself by performing both actuation and sensing functions. The same component that opens the door also detects the user's intent to open it, eliminating the need for additional dedicated sensing components and simplifying the overall system structure.
2Measurement precision
If a separate sensor facility is added to detect pressure actuations, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The stator winding performs dual roles: as an electromagnetic actuator when voltage is applied, and as a pressure sensor when voltage is not applied. This multi-functionality eliminates the need for separate sensor facilities while maintaining accurate detection of pressure actuations through induced voltage measurement.
Solution Approach 2:
The sensing function is merged with the existing stator winding of the rotating electric machine rather than being implemented as a separate component. The stator winding's inherent electromagnetic properties are utilized for both actuation and sensing, combining multiple functions into a single component.
3Reliability
If the plunger is permanently supported against the door inner face, then the sensor reliability is improved, but the use of energy increases due to continuous motor operation
Solution Approach 1:
The plunger is supported against the door inner face periodically rather than continuously. The mechanical support unit applies force only during the detection phase (when voltage is not applied to the stator winding), and the plunger is retracted during the actuation phase. This periodic action maintains reliable detection capability while minimizing energy consumption by keeping the rotating electric machine inactive during detection.
4Use of energy by moving object
If the plunger is retracted from the door inner face, then the use of energy is reduced, but the reliability of door opening request detection deteriorates
Solution Approach 1:
The system alternates between detection mode (plunger supported against door) and actuation mode (plunger retracted). During detection, the plunger is supported to enable reliable pressure sensing. During actuation, the plunger is retracted and the rotating electric machine is activated. This periodic switching maintains both energy efficiency and detection reliability.
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 allows for reliable detection of door opening requests without the need for additional sensors, improving user convenience and accessibility, especially for individuals with disabilities, while also reducing energy consumption and complexity compared to prior art.
Implementation Method 1
outside of the application of the electrical voltage to the stator winding (30) a force is applied to the plunger (12) by means of a mechanical support unit (17) and by means of a sensor facility which is electrically coupled to the stator winding (30) an induced voltage of the stator winding (30) is detected outside of the application of the electrical voltage to the stator winding (30)
Data Source
AI summary
A method determines a door opening request based on a pressure actuation against a door of a household appliance. A plunger is driven by an electric machine via a transmission. An electrical voltage is applied to a stator winding which is electrically coupled to a control unit at least during temporary support of the plunger head against a door inner face. When the door is in the closed state a force is applied to the plunger and by a sensor facility a stator winding-side induced voltage is detected, which has a voltage pulse depending on the pressure actuation. An amplitude of the voltage pulse is compared in a first comparison with a voltage comparison value and a temporal extent of the voltage pulse is compared in a second comparison with a time comparison value. The door opening request is determined depending on comparison results of the first and second comparison.