Motorized Window Treatment Position Tracking Through 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 adjust the position calculation, ensuring accurate determination of the covering material's position and preventing misalignment.
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 inaccuracies in position determination due to hysteresis in sensor signal generation
Solution Approach 1:
The control circuit stores the last determined position and sensor states in memory before a power loss event occurs. This preliminary storage of data allows the system to reconstruct the position accurately after power restoration by comparing stored sensor states with current sensor states, thereby resolving the contradiction between measurement precision and reliability after power loss.
Solution Approach 2:
The system implements a feedback mechanism where the control circuit compares the stored sensor states with the current sensor states after power restoration. Based on this comparison and the stored last determined position, the system calculates and corrects the present position, ensuring accurate position determination despite the power loss event that caused hysteresis in sensor signal generation.
2Productivity
If the motor continues to rotate during power loss event, then the system can maintain operation, but the position accuracy deteriorates because sensor states become inconsistent with actual position
Solution Approach 1:
Before the power loss event fully impacts sensor accuracy, the control circuit stores the last determined position and corresponding sensor states in memory. This preliminary action preserves the reference data needed to later correct position measurements, allowing the motor to continue rotating during power loss while maintaining the ability to recover accurate position information afterward.
Solution Approach 2:
After power restoration, the control circuit uses feedback by comparing the stored sensor states with current sensor states to detect inconsistencies caused by continued motor rotation during power loss. The system then calculates the present position based on the stored last determined position and the difference in sensor states, thereby correcting the position measurement accuracy while allowing continuous operation.
3Measurement precision
If the control circuit stores sensor states during power loss, then position accuracy can be restored after power-up, but the complexity of the control circuit increases
Solution Approach 1:
The control circuit stores only the last determined position and the sensor states corresponding to that position in memory before power loss. This selective preliminary storage of critical reference data enables position recovery after power-up without requiring the circuit to store or process all sensor data, thereby limiting the increase in control circuit complexity while maintaining position determination accuracy.
Solution Approach 2:
The control circuit implements a relatively simple feedback mechanism that compares stored sensor states with current sensor states and calculates the present position based on the stored last determined position. This feedback approach uses basic comparison and calculation operations rather than complex algorithms, resolving the contradiction between achieving accurate position determination after power-up and minimizing control circuit complexity.
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 accurately reconstructs the position of movable components after power loss events, preventing misalignment and damage, and enhances the reliability of motorized window treatment systems by correcting inaccuracies and ensuring operation within set limits.
Implementation Method 1
inaccurate sensor state detection, which may in turn result in inaccurate determination of the present position. Such inaccuracies may be caused by hysteresis in the generation of the states (e.g., a high state versus a low state) of the signals produced by circuitry used to sense magnetic fields associated with rotations of the motor (e.g., a Hall-Effect sensor circuit).
Data Source
AI summary
Motorized window treatment systems are disclosed. A motorized window treatment system may include a covering material, a sensor circuit, and a control circuit. The sensor circuit may be configured to generate sensor signals indicative of a position of the covering material. The control circuit may be configured to determine a present sensor state of the sensor circuit, determine a predicted sensor state for the sensor circuit based at least in part on a power-down position recorded at a first time and a final position recorded at a second time, compare the predicted sensor state with the present sensor state, and determine a present position of the covering material based on the comparison of the predicted sensor state and the present sensor state. Methods of adjusting a position of a covering material of a motorized window treatment also are disclosed.