Accelerometer-Based Roller Blind Position Measurement
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Solution Overview
Problem
Existing home automation equipment faces challenges in controlling motorized devices due to non-linear relationships between motor rotation and equipment movement, leading to difficulties in controlling force and precision, especially when encountering obstacles or stops, and current sensor solutions often require physical contact or are limited by structural periodicity.
Innovation Solution
A method that uses a motion sensor with a three-axis accelerometer integrated with the mobile element, allowing contactless measurement of acceleration, speed, and displacement, which is then used to establish a relationship between motor rotation and equipment position, enabling precise control without physical contact and accounting for structural clearances and variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotation sensor is arranged at the output of the motor, then the sensor can measure motor rotation, but the play of the reducer and hysteresis significantly influence the relationship between sensor value and equipment position
Solution Approach 1:
The patent replaces the mechanical rotation sensor system with an accelerometer-based measurement system. Instead of measuring motor rotation mechanically and dealing with reducer play and hysteresis, the system uses an accelerometer to directly measure the mobile element's acceleration, then integrates this data to determine position, velocity and acceleration without mechanical transmission components.
Solution Approach 2:
The patent introduces an intermediary processing system that takes raw accelerometer data and transforms it into meaningful position and velocity information through integration and filtering algorithms. This intermediary layer converts the raw acceleration measurements into reliable position data, eliminating the direct mechanical coupling problems.
2Measurement precision
If a motion sensor is placed on the mobile element requiring physical contact, then the sensor can measure movement directly, but serious installation constraints are created
Solution Approach 1:
The patent replaces contact-based mechanical sensors with a contactless accelerometer system. The accelerometer can be mounted on the mobile element without requiring physical contact between fixed and moving parts, eliminating complex mechanical mounting structures while maintaining measurement precision.
3Ease of operation
If the same rotational displacement value is used, then motor control is simplified, but very different apron displacement values occur depending on winding diameter
Solution Approach 1:
The patent implements feedback by continuously measuring the mobile element's actual position using the accelerometer and using this information to adjust motor control. The system integrates acceleration data to obtain real-time position feedback, which is then used to control motor rotation, ensuring precise apron displacement regardless of winding diameter changes.
Solution Approach 2:
The patent transitions from static motor control (fixed rotational displacement values) to dynamic control where the relationship between motor rotation and apron displacement is continuously adjusted based on real-time acceleration measurements and integration, adapting to changing winding conditions.
4Reliability
If force control is attempted with non-linear relationship, then obstacle detection is possible, but real difficulty in controlling force not to be exceeded occurs
Solution Approach 1:
The patent uses feedback from accelerometer measurements to monitor the mobile element's motion and detect obstacles. By integrating acceleration data to obtain velocity and position information, the system can detect abnormal conditions (such as unexpected stopping or reversal indicating obstacle contact) and adjust motor torque accordingly, simplifying force control through intelligent monitoring rather than complex mechanical force sensing.
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 allows for accurate and controlled operation of home automation equipment by overcoming non-linearity issues, ensuring safe stopping and precise positioning, even in complex movements, while reducing installation constraints and improving precision and reliability.
Implementation Method 1
at least one internal quantity relating to the rotation of the motor is measured by the control unit, and at least one quantity image of the acceleration, the speed and/or the displacement of the reference element of the mobile element is obtained
Data Source
Figure 1~3
Figure 2
AI summary
The method involves obtaining a characteristic quantity e.g. angle, of displacement of a movable element (COV), during supplying of a motor (MOT), by integrating physical quantity provided by an accelerometer (ACC) to an internal quantity (ROT) e.g. activation duration value, of an actuator (ACT), where the accelerometer is fixed to the movable element. The relation between the characteristic quantity and the internal quantity is obtained. Independent claims are also included for the following: (1) a method for controlling an actuator (2) a home automation equipment for closing, occultation, solar protection or screen.