Motorized Drive Device Speed Control for Roller Shutter Stress Reduction
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Solution Overview
Problem
Existing motorized drive devices for closing or solar protection systems, such as roller shutters and blinds, experience mechanical stress during acceleration and deceleration phases due to the inherent limitations of soft start and soft stop functions, which do not adequately mitigate stress on the motion transmission chains.
Innovation Solution
A control method that adjusts the rotational speed of the electromechanical actuator's output shaft, employing a first rotational speed setpoint for positions upstream of an approach zone and a second, lower rotational speed setpoint for positions within the approach zone, thereby reducing mechanical stress on the transmission chains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If soft stop and soft start functions are implemented with fixed time or amplitude parameters, then noise is avoided and mechanical stresses are limited, but the transmission chains remain stressed during acceleration and deceleration phases
Solution Approach 1:
The patent applies dynamics by making the rotational speed setpoint adjustable based on the moving element's position. The system transitions from fixed parameters to dynamic parameters, where the first rotational speed setpoint is used when the moving element is outside the approach zone, and the second, lower rotational speed setpoint is used when inside the approach zone. This dynamic adjustment reduces mechanical stress during critical phases while maintaining productivity during normal operation.
Solution Approach 2:
The patent changes the operational parameters by introducing position-dependent rotational speed setpoints. Instead of using a single fixed speed parameter, the system switches between at least two different rotational speed setpoints based on the moving element's position relative to the approach zone. This parameter change allows optimization of both stress reduction and operational efficiency.
2Stress or pressure
If a single rotational speed setpoint is used throughout the entire travel range, then operational simplicity is maintained, but mechanical stress cannot be adequately reduced during approach phases
Solution Approach 1:
The patent segments the travel range into at least two distinct zones: the approach zone and the rest of the travel range. This segmentation allows different rotational speed setpoints to be applied to different segments, optimizing stress reduction in the approach zone while maintaining efficient operation in other zones. The control system determines which zone the moving element is in and applies the appropriate speed setpoint accordingly.
Solution Approach 2:
The patent applies local quality by assigning different rotational speed characteristics to different spatial locations. The first rotational speed setpoint is applied when the moving element is outside the approach zone, while the second, lower rotational speed setpoint is applied specifically when the moving element is inside the approach zone. This localized approach ensures stress reduction exactly where needed without compromising overall system performance.
3Stress or pressure
If rotational speed is reduced throughout the entire operation, then mechanical stress is minimized, but operational efficiency and productivity decrease
Solution Approach 1:
The patent applies partial action by reducing the rotational speed setpoint only partially and only in specific conditions. Instead of reducing speed throughout the entire operation, the system uses the lower second rotational speed setpoint only when the moving element is inside the approach zone, while maintaining the higher first rotational speed setpoint during the rest of the travel. This partial application of speed reduction minimizes stress during critical phases while preserving productivity during normal operation.
Data Source
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AI summary
Method for controlling the operation of a motorized drive device for a home automation closure or sunscreen installation comprising a screen, a winding tube, an electromechanical actuator for moving the screen and including an output shaft, said method involving the following steps: - acquisition of a command to move the screen; - selection of a position in which to stop the screen according to the screen movement command acquired; - determination of a current position of the screen; - movement of the screen at a first electromechanical actuator output shaft rotational reference speed when the determined current position of the screen is upstream of a position in which the screen enters a zone nearing the selected stopping position; - and if not, movement of the screen at a second electromechanical actuator output shaft rotational reference speed, the second rotational reference speed being lower than the first rotational reference speed.