Loom Actuator Control via Dynamic Setpoint Generation

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Solution Overview

Problem

Existing methods for controlling electric actuators on looms are inefficient in adapting the movement profile of heddles to optimize weaving, leading to increased accelerations and stress on moving parts due to limited generic curves and inability to account for modifications during the weaving process.

Innovation Solution

A method that generates optimized setpoint data for each pick and actuator or group of actuators by determining remarkable points and using parametrized approximation functions to calculate accelerations and movement laws, allowing dynamic adaptation to shedding parameters and ensuring smooth connections between picks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If generic curves are used to calculate position setpoints for actuators, then the control method is simple and curves are pre-defined, but the number of generic curves is limited and cannot adapt to optimize heddle movement during weaving

Engineering Contradiction:
Improveadaptability to shedding parametersVSAvoidcomplexity of control method
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic generation of position setpoints during the weaving process, transitioning from static pre-defined generic curves to dynamic calculation based on actual shedding parameters. The control device calculates position setpoints in real-time using a mathematical model that adapts to varying shedding parameters, enabling optimization of heddle movement profiles during weaving operations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the approach from using fixed generic curves to calculating position setpoints based on variable shedding parameters. The mathematical model uses parameters such as pick duration, heddle position, and weaving pattern to dynamically generate optimized movement profiles, allowing adaptation to different weaving conditions without being constrained by a limited library of pre-defined curves.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If position setpoints are calculated for the entire weave before starting, then complex calculations can be performed, but modifications of shed parameters during weaving cannot be taken into account

Engineering Contradiction:
Improveprecision of position controlVSAvoidability to account for parameter modifications
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent performs preliminary calculation of position setpoints based on the mathematical model and shedding parameters before each pick operation. By calculating the optimal movement profile in advance for each pick, the system ensures precise position control while maintaining the ability to adapt to parameter modifications during weaving, as the calculations are updated for each new pick based on current parameters.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control device continuously receives shedding parameters during weaving and uses this feedback to recalculate position setpoints for subsequent picks. This feedback mechanism allows the system to adapt to modifications in shed parameters while maintaining precise position control through real-time calculation updates based on the mathematical model.

Inventive Principle:
Principle #23Feedback

3Productivity

If the time available for movement is less than the duration of a pick, then the weaving process is efficient, but the accelerations to which moving parts are subjected increase

Engineering Contradiction:
Improveweaving efficiencyVSAvoidaccelerations on moving parts
Core Design Contradiction:
ProductivityVSStress or pressure

Solution Approach 1:

The patent uses the mathematical model to optimize movement parameters including acceleration profiles, ensuring that heddles reach their target positions within the pick duration while minimizing excessive accelerations. The model calculates optimal acceleration values based on pick duration, heddle mass, and required position changes, balancing weaving efficiency with reduced mechanical stress on moving parts.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2357271B1Method for controlling electrical actuators of a shedding device
Publication Date: 2015.05.27 STAUBLI FAVERGES SA
  • EP2357271B1 patent drawingFigure 1
  • EP2357271B1 patent drawingFigure 2~3
  • EP2357271B1 patent drawingFigure 4

AI summary

The method involves determining remarkable points of a smooth movement profile driven by an actuator or group of actuators according to shed parameters, and determining approximation parameterized function of the profile. Six accelerations are calculated, and a law of smooth movement is determined for a data pick such that the smooth accelerations at beginning and ending of its movement are equal to the fifth and sixth accelerations. A set of setpoint data is generated for the data pick and the actuator or group of actuators, from the determined law of movement.