Roller Shutter Drive Calibration for Sensor-Free Position Accuracy
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Solution Overview
Problem
Existing methods for controlling electric roller shutters lack precision in correlating motor running time with the open/closed state, often resulting in deviations of more than 25% from calculated positions, necessitating a more accurate relationship between drive time and shutter state without relying on position sensors.
Innovation Solution
A method and device that utilize a reference point on the roller shutter to establish a one-to-one relationship between height and time, accounting for non-uniform speed and slat movement, with drive durations measured and stored to compensate for deviations up to 25%, using mathematical calculations to ensure precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simple ratio formation is used to calculate roller shutter position based on motor running time, then the control system remains simple and sensor-free, but the position accuracy deteriorates with deviations exceeding 25%
Solution Approach 1:
The system performs preliminary calibration by measuring the actual drive duration from the lower stop position before normal operation. This pre-measured time value is stored and used for subsequent position calculations, enabling accurate positioning without requiring sensors during actual operation.
Solution Approach 2:
The system changes the parameter used for position calculation from a theoretical constant ratio to an empirically measured drive duration. By replacing the assumed linear relationship with actual measured time data, the system achieves high position accuracy while maintaining simple sensor-free control.
2Speed
If the motor runs at constant speed, then the relationship between running time and shutter position should be linear, but non-uniform speed causes significant deviation from calculated positions
Solution Approach 1:
The system incorporates feedback by measuring the actual drive duration required to move the roller shutter from the lower stop position to the upper stop position. This measured time feedback replaces theoretical constant-speed assumptions, allowing the control system to compensate for non-uniform motor speed and achieve accurate positioning.
3Measurement precision
If position sensors are installed to achieve precise positioning, then positioning accuracy improves, but device complexity and cost increase
Solution Approach 1:
The system uses the motor's own running time as a self-service measurement parameter to determine shutter position. By utilizing the motor's operational characteristics and measured drive duration, the system eliminates the need for external position sensors, achieving both simplicity and accuracy.
Data Source
Figure 1~3
Figure 4
AI summary
The invention relates to a method for operating an electric drive (3) for a roller shutter (1). The invention further relates to a device (36) configured for carrying out the method according to the invention. The purpose of the method is to drive the roller shutter (1) according to a specified value (between 0% and 100%) until it is opened as precisely as specified. Conversely, the method also makes it possible to provide the point-in-time state (7) of opening when moving the roller shutter. The solution concept consists of applying a one-to-one relationship (II,III,35) that at least approximately represents the characteristics of a roller shutter (1).