Appliance Door Status Detection Using Switch and Latch Feedback
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Solution Overview
Problem
Conventional appliance door lock control systems fail to accurately determine the status of the appliance door, leading to inefficiencies as they only consider the latch motor's state, ignoring the door's position, which can result in the door lock latch engaging without properly locking the door.
Innovation Solution
A control system that includes a door switch coupled in series with a latch motor feedback, allowing a controller to determine the appliance door's state by analyzing output signals from the door switch and latch commands, thereby ensuring accurate locking and unlocking operations without additional inputs or hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only latch motor state is considered for door locking control, then the control system is simple, but the door status determination is inaccurate
Solution Approach 1:
The patent combines the door switch signal and latch motor feedback signal into a single integrated control input for the controller. This merging allows the system to determine door status accurately by analyzing the relationship between the door switch state and latch motor state through software logic, rather than requiring separate hardware inputs for each signal, thus improving measurement precision without significantly increasing device complexity
Solution Approach 2:
The patent uses the controller's processing capability as an intermediary to interpret the combined signal from the door switch and latch motor feedback. The controller analyzes the temporal relationship and logical consistency between these signals to determine actual door status, effectively using software-based mediation to resolve the contradiction between signal integration and system complexity
2Device complexity
If door switch is coupled in series with latch motor feedback, then the number of control inputs is reduced, but the signal interpretation becomes more complex
Solution Approach 1:
The patent employs feedback logic where the controller continuously monitors the relationship between the door switch state and latch motor feedback state. By analyzing whether changes in the combined signal correspond to expected temporal sequences (door switch changes first, then latch motor responds), the controller can distinguish between genuine door status changes and latch motor operations, reducing signal interpretation complexity through pattern recognition
Solution Approach 2:
The system establishes predetermined logical rules and temporal expectations for how door switch and latch motor signals should interact under normal operating conditions. By having these interpretation rules pre-programmed in the controller, the system can automatically distinguish between different signal sources without real-time complex analysis, thus reducing the difficulty of signal interpretation
Data Source
AI summary
A system and method of determining the status of an appliance door is provided. The status of the door of the appliance can be determined based an output signal provided by a door switch coupled in series with a latch motor feedback. A change in the output signal of the door switch can be indicative of either the opening of the appliance door or the actuating of the latch motor. The source of the change in an output of the door switch can be determined based on the latch command provided to the latch motor. The appliance can be controlled based on the status of the appliance door.