Motorized Window Treatment Position Tracking After Power Loss
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Solution Overview
Problem
Motorized window treatments experience inaccuracies in determining the position of movable components due to power loss events, leading to potential damage or aesthetic issues, especially when power is restored, as the sensor states may not match the actual position accurately.
Innovation Solution
A motorized window treatment system with a control circuit that detects power loss events by monitoring voltage thresholds, stores accurate sensor states before power loss, and upon restoration, compares predicted and present sensor states to correct the determined position, using adjustment factors if necessary.
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 is restored, compensating for the hysteresis-induced inaccuracies that would otherwise occur during sensor signal generation upon power-up.
Solution Approach 2:
The control circuit compares the stored sensor states with the present sensor states after power-up to detect discrepancies caused by hysteresis. Based on this feedback comparison, the system adjusts the reconstructed position to compensate for the detected inaccuracies, ensuring accurate position determination despite the power loss event.
2Productivity
If the motor continues to rotate during power loss event, then the system can maintain operation, but the position determination becomes inaccurate due to inconsistent sensor states between power loss and power-up
Solution Approach 1:
The control circuit creates a copy of the sensor states and position data at the moment of power loss. This copied data serves as a reference that remains valid even if the motor continues to rotate during the power loss event. After power-up, the system uses this copied reference data to accurately reconstruct the position, regardless of any rotation that occurred during the power interruption.
3Loss of time
If the control circuit stores sensor states during operation, then position can be tracked, but power loss causes the stored position to not accurately reflect the present position upon power-up
Solution Approach 1:
The control circuit performs preliminary storage of both the determined position and the corresponding sensor states in memory before power loss occurs. This dual storage approach ensures that when power is restored, the system has both the position information and the sensor state reference needed to accurately reconstruct the position, maintaining continuity without accuracy loss.
Solution Approach 2:
The control circuit uses the stored sensor states as a feedback reference to verify and adjust the reconstructed position after power-up. By comparing the stored sensor states with the present sensor states, the system can detect and correct any discrepancies, ensuring that the position tracking remains accurate and reliable after power restoration.
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
Ensures accurate determination of the movable component's position after power loss events, preventing movement beyond set limits and maintaining aesthetic alignment, thus avoiding damage and operational inefficiencies.
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.