Actuator Obstacle Detection via Transient Torque

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Solution Overview

Problem

Existing electromechanical actuators for shading or solar protection systems, such as blinds and rolling shutters, face challenges in detecting obstacles during deployment due to mechanical limitations and power transmission constraints, particularly in slatted blinds and flexible fabric awnings, leading to inefficient and unreliable obstacle detection.

Innovation Solution

An electromechanical actuator with an obstacle generation device that creates a transient force when an obstacle is encountered, allowing for reliable and quick detection through torque measurement, independent of motor power supply and operating conditions, enabling precise control and reduced torque requirements during obstacle passage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If motor torque monitoring is used to detect obstacles, then obstacle detection capability is improved, but detection precision is worsened because obstacles can only be detected after significant stacking of slats or unwinding of blades

Engineering Contradiction:
Improveobstacle detection capabilityVSAvoiddetection precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent divides the obstacle detection function into two distinct mechanisms: a first obstacle generation device that creates transient forces during normal operation for precise detection, and a second obstacle generation device that creates permanent forces for backup detection. This segmentation allows each device to specialize in different detection scenarios, resolving the contradiction between reliability and precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first obstacle generation device creates transient forces before the motor encounters actual mechanical resistance from an obstacle. By generating these transient forces in advance during the unrolling process, the system can detect obstacles earlier and more precisely, before significant slat stacking occurs, thus improving both detection precision and reliability.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If remote sensors are used for obstacle detection, then detection precision is improved, but device complexity is worsened due to power supply routing and information transmission requirements

Engineering Contradiction:
Improvedetection precisionVSAvoidinstallation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The actuator generates its own test signals through the obstacle generation devices and detects obstacles using its own torque monitoring capabilities. This self-service approach eliminates the need for external remote sensors, power supply routing, and separate information transmission systems, significantly reducing installation complexity while maintaining detection precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent merges the obstacle detection function with the actuator's existing torque monitoring system. By integrating the obstacle generation devices into the actuator itself and using the same torque sensor for both motor control and obstacle detection, the system eliminates separate sensing systems and their associated complexity while maintaining high detection precision.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If fixed stops are used to limit actuator rotation, then reliability is improved by preventing over-rotation, but measurement precision is worsened because the force generated cannot be effectively detected without torque control

Engineering Contradiction:
Improverotation limitationVSAvoidforce detection capability
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces static fixed stops with dynamic obstacle generation devices that create transient forces during actuator operation. These transient forces vary dynamically during the unrolling process, allowing the torque sensor to detect them effectively against the background of varying motor torque, thus improving force detection capability while maintaining rotation limitation reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The obstacle generation devices create preliminary transient forces that counteract or highlight the effects of fixed stops. By generating these transient forces before the actuator encounters the fixed stop, the system can detect the stop's presence through torque variations, improving force detection capability while maintaining the protective function of the stops.

Inventive Principle:
Principle #9Preliminary anti-action

4Measurement precision

If elaborate electronic functions or complex mechanisms are used for obstacle detection, then detection precision is improved, but device complexity is worsened and reliability is reduced due to higher cost and maintenance requirements

Engineering Contradiction:
Improvedetection precisionVSAvoidmechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The actuator uses its own motor and torque sensor to generate test signals and detect obstacles, eliminating the need for elaborate external electronic functions or complex mechanical mechanisms. This self-service approach simplifies the overall system while maintaining high detection precision through intelligent processing of torque data.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent detects obstacles by monitoring changes in torque parameters during actuator operation. By analyzing transient force patterns, torque magnitudes, and temporal characteristics, the system achieves high detection precision using simple torque sensing rather than complex electronic or mechanical mechanisms, thereby reducing device complexity while improving reliability.

Inventive Principle:
Principle #35Parameter changes

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 reliable and rapid detection of transient obstacles along the deployment path, improving the actuator's ability to stop at desired positions and reducing wear on moving parts, suitable for various types of shading systems including soft fabric awnings.

Implementation Method 1

an obstacle generation device, comprising at least one obstacle element, and which creates a transient force when the motor drives the mobile screen, this transient force resisting the transmission of movement between the entry part and the part output

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a detection means of the resistant transient force, by detecting the torque at the output of the actuator

Methodology Applied
Scientific EffectTorque: Torque

Data Source

PatentEP2746526B1Electromechanical actuator, closing or sun-protection system comprising such an actuator and method for monitoring such an actuator
Publication Date: 2016.06.08 SOMFY SAS
  • EP2746526B1 patent drawingFigure 1
  • EP2746526B1 patent drawingFigure 2~4
  • EP2746526B1 patent drawingFigure 5~7

AI summary

The actuator has an asynchronous motor for providing a set of movements to a kinematic chain, and a reducer. An output transmission shaft is arranged for transmission of movement provided by the motor. An input part (60) and an output part (70) are movable with regard to each other with a limited play. An obstacle generation device includes a set of cams (72-1, 72-2) that is ready to create a transitory resistant force for movement transmission between the input part and output part. A control unit detects the transitory resistant force. An independent claim is also included for a method for checking operation of the electromechanical actuator.