Motorized Shade Position Recovery After Power Loss
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Solution Overview
Problem
Motorized window treatment systems face inaccuracies in determining the position of movable components after power loss events, leading to potential misalignment and damage due to hysteresis in sensor signal generation and continued motor rotation during power loss.
Innovation Solution
A control circuit that detects power loss by monitoring supply voltage, stores accurate sensor states before power loss, and upon power-up, compares predicted and present sensor states to calculate the correct position of the covering material, adjusting for any discrepancies to ensure accurate positioning and prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the motor drive unit uses sensor states to determine the present position of the covering material, then the position can be monitored for control purposes, but power loss events cause inaccurate sensor state detection leading to position inaccuracies
Solution Approach 1:
The system stores the last known accurate position and sensor states in memory before a power loss event occurs. When power is restored, this previously stored information serves as a baseline to detect and correct any position drift caused by the power interruption, thereby maintaining measurement precision despite the reliability issue during power loss.
Solution Approach 2:
The control circuit compares the stored sensor states from before power loss with the current sensor states after power restoration. This feedback mechanism identifies discrepancies caused by the power loss event and triggers corrective actions to recalculate the accurate present position, ensuring continued measurement precision.
2Productivity
If the motor continues to rotate during power loss event, then the system may respond to operational demands, but the determined present position becomes inconsistent with actual position
Solution Approach 1:
The system creates a copy of the sensor states and position information at the moment before power loss. This copied data serves as a reference snapshot that allows the system to later compare against actual sensor readings after power restoration, identifying and correcting position measurement errors that occurred during the power loss period when the motor continued rotating.
3Stability of the object's composition
If hysteresis is present in sensor signal generation, then the sensor can generate stable states, but the determined present position may shift in one direction or the other
Solution Approach 1:
By continuously comparing stored sensor states with current sensor states and detecting discrepancies, the system provides feedback that identifies when hysteresis has caused position determination errors. This feedback enables the control circuit to calculate corrective adjustments and recalculate the accurate present position, thereby compensating for the stability issues introduced by hysteresis in the sensor signal generation.
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 ensures accurate reconstruction of the movable component's position after power loss events, preventing misalignment and damage, and maintaining aesthetic and operational integrity of the motorized window treatment system.
Implementation Method 1
A control circuit that detects power loss by monitoring supply voltage
Implementation Method 2
a Hall-Effect sensor circuit
Data Source
AI summary
A motorized window treatment system is provided for moving a covering material (e.g., a shade fabric). The motorized window treatment system includes a motor drive circuit configured to generate signals that cause a motor to change a position of the covering material. A sensor circuit is provided to generate one or more sensor signals indicative of the position of the covering material. The motorized window treatment system further includes a control circuit coupled to the sensor circuit to receive the one or more sensor signals. The control circuit is configured to detect a power-down event when a supply voltage is equal to or less than a threshold value, and stores a power-down position and one or more power-down sensor states. The control circuit is configured to determine a present position based on the stored power-down position and the one or more power-down sensor states.