Clutch-Based Roller Shade Obstacle Detection via Force Sensor
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Solution Overview
Problem
Motorized roller shades lack effective obstacle detection when the shade material is being lowered, leading to potential damage to the shade material, motor, or hardware due to external obstructions, as current sensors are unable to detect changes in current draw during this process.
Innovation Solution
A motorized clutch-based roller shade system equipped with a force sensor that detects abrupt changes in reaction force, allowing the motor control module to control the motor's operation in response to external forces or obstacles, including the use of a force sensing film resistor or other sensors to determine torque changes and prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clutch mechanism is used to prevent motor rotation during rest, then the motor is protected from unintended movement, but obstacle detection capability is lost when shade material is being lowered
Solution Approach 1:
A force sensor is introduced as an intermediary component between the clutch mechanism and the motor. The force sensor detects external forces applied to the shade material and transmits this information to the motor control module, enabling obstacle detection without compromising the clutch's motor protection function. This intermediary sensor allows the system to monitor conditions that would otherwise be hidden by the clutch's torque isolation.
Solution Approach 2:
The patent replaces the traditional mechanical obstacle detection method (relying on motor current sensors and clutch feedback) with a dedicated force sensing mechanism. The force sensor directly measures external forces on the shade material, substituting the indirect mechanical detection approach with a more direct and reliable sensing method that works effectively even when the clutch is engaged.
2Stability of the object's composition
If motor braking techniques are used to prevent motor rotation at rest, then motor stability is improved, but the ability to detect user pulling actions is reduced
Solution Approach 1:
The force sensor detects user pulling actions before the motor needs to respond. By monitoring forces on the shade material in advance, the system can prepare to execute user commands (such as initiating motorized raising or lowering) without delay, maintaining ease of manual operation while preserving motor stability when not in use.
Solution Approach 2:
The force sensor enables the system to automatically detect and respond to user intentions without requiring direct motor engagement. When a user pulls on the shade material, the sensor detects this action and triggers appropriate motorized response, allowing the system to serve itself by converting manual pulling into automated motor control, thereby maintaining both stability and ease of 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
Enables automatic detection and prevention of damage by controlling the motor's operation based on force changes, allowing safe and reliable operation of the roller shade, minimizing damage to the shade and users.
Implementation Method 1
a force sensor positioned at a point along the motor drive unit that resists the torque created by the motor resulting in a reaction force that is detected by the force sensor
Data Source
AI summary
A motorized shade comprising a roller tube, a shade material connected to the roller tube, and a motor drive unit operably connected to the roller tube. The motor drive unit comprises a motor adapted to create torque to rotate the roller tube to lower or raise the shade material and a force sensor positioned at a point along the motor drive unit that resists the torque created by the motor resulting in a reaction force that is detected by the force sensor. The motor drive unit further comprises a motor control module adapted to receive sensor readings from the force sensor and control the motor in response to detecting an abrupt change in the reaction force using the received sensor readings to enable shade control via pulling of the shade material as well as or alternatively obstacle detection to minimize damage to the roller shade and users.