Oven Control Panel Stepper Positioning Without Sensors
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Solution Overview
Problem
Existing household appliances with movable components, such as tilting control panels, face challenges in reliable and cost-effective motorized movement control, particularly when using stepper motors, as they require precise positioning and torque management to avoid damage to drive mechanisms.
Innovation Solution
A method involving detection of power-up to move a member to a reference position and subsequent displacement to operating positions by controlling the stepper motor's rotation based on predefined angular steps, with reduced current supply during initial positioning to prevent damage and sufficient torque for movement between positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a stepper motor is used to move the control panel, then the control can be simplified and position sensors can be avoided, but the risk of drive mechanism damage increases due to uncontrolled torque
Solution Approach 1:
The control method performs preliminary positioning by moving the control panel to a reference position upon power-up before normal operation. This preliminary action establishes a known starting point and allows the system to detect the initial position, thereby preventing uncontrolled torque application that could damage the drive mechanism.
Solution Approach 2:
The system changes the motor control parameters by implementing different control strategies: during preliminary positioning, the motor is controlled to stop precisely at the reference position, and during normal operation, the motor is controlled based on predefined angular steps. This parameter change approach allows sensorless operation while maintaining drive mechanism protection.
2Reliability
If the stepper motor is powered by limited current during reference positioning, then the risk of drive mechanism damage is reduced, but the torque available for movement is decreased
Solution Approach 1:
The control method applies partial action by using limited current only during the specific phase of reference positioning, rather than continuously. This partial application of reduced current is sufficient for the positioning task while avoiding excessive torque that could damage the drive mechanism, and the full current is restored when needed for normal operation.
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 approach simplifies control of movable components without position sensors, reduces the risk of drive mechanism damage, and maintains sufficient torque for reliable operation, making it a cost-effective solution for household appliances like cooking ovens and washing machines.
Implementation Method 1
the movement of this control panel can in particular be achieved by drive means actuated by a motor
Data Source
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AI summary
The method involves detecting charging of an electrical appliance by a detection unit (45), and moving a mobile component towards a reference position during detection of charging of the electrical appliance. The component is moved towards one of two operating positions by controlling rotation of a stepper motor according to a predefined number of steps of the motor. An opening of an electronic switch (T) is handled by electronic control units (43) from a clock (44) that generates pulses for alternatively opening and closing the switch. An independent claim is also included for an electrical appliance comprising a mobile component.