Laser Welding Path Tracking With Dynamic Analysis Region

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Solution Overview

Problem

Existing laser welding and cutting methods face challenges in maintaining accuracy and error robustness, especially when the manipulator and beam control system undergo superimposed movements, as the position and orientation of the image section relative to the workpiece change constantly, leading to deviations in the laser beam positioning.

Innovation Solution

A method and device that utilize a laser beam guided by a manipulator and a beam control system with movable mirrors, where the position of a reference feature on the workpiece is determined online using an optical detection system within a partial analysis area of the detection system, allowing for dynamic adjustment of the analysis area to maintain accuracy and adapt to position deviations, and the laser beam is readjusted accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the detection area is reduced to an analysis area to increase evaluation speed, then productivity is improved, but measurement precision deteriorates due to limited detection coverage

Engineering Contradiction:
Improveevaluation speedVSAvoidposition determination accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent dynamically adapts the analysis area within the detection area based on the expected position of the web and reference features. The analysis area is not fixed but is adjusted in real-time to follow the workpiece position, allowing the system to maintain high evaluation speed while continuously tracking the relevant features with improved precision.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs preliminary determination of the web's approximate position and orientation before defining the analysis area. This preliminary action allows the analysis area to be pre-positioned to cover the expected location of reference features, ensuring both fast evaluation and accurate measurement from the start of processing.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the manipulator and beam control system undergo superimposed movements to increase flexibility, then adaptability is improved, but manufacturing precision deteriorates due to constant position changes

Engineering Contradiction:
Improvemovement flexibilityVSAvoidlaser beam positioning accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback mechanism where the optical detection system continuously monitors the position of reference features on the workpiece. Based on this feedback, the system dynamically adjusts the analysis area and compensates for position deviations caused by superimposed movements of the manipulator and beam control system, maintaining manufacturing precision despite movement flexibility.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adapts the analysis area to follow the workpiece position during superimposed movements. By making the analysis area movable and adjustable rather than fixed, the system maintains accurate tracking of reference features even as the manipulator and beam control system undergo complex coordinated movements.

Inventive Principle:
Principle #15Dynamics

3Productivity

If the analysis area is kept small to improve evaluation speed, then productivity is improved, but reliability deteriorates when the reference feature moves outside the analysis area

Engineering Contradiction:
Improveevaluation speedVSAvoidfeature tracking robustness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent makes the analysis area dynamic by continuously adapting its position and size based on the expected location of reference features. This dynamic adaptation ensures that the reference feature remains within the analysis area during superimposed movements, maintaining both high evaluation speed and reliable feature tracking.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs preliminary determination of the web position and orientation to predict where reference features will be located. This preliminary action allows the analysis area to be positioned in advance to cover the expected feature locations, ensuring reliable tracking while maintaining fast evaluation speed.

Inventive Principle:
Principle #10Preliminary action

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 approach enhances the accuracy and error robustness of laser welding and cutting processes by ensuring the reference feature remains within the analysis area during superimposed movements, allowing for continuous improvement in precision and speed.

Implementation Method 1

an optical detection system which comprises a point-distance sensor with a detection area

Methodology Applied
Scientific EffectOptical detection: Reflection

Implementation Method 2

a laser beam is generated as a function of movement data from a manipulator

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 3

a high-energy beam focused on a processing zone of a workpiece

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP3102359B1Method and device for laser welding or cutting with a dynamically adaptable analysis region
Publication Date: 2021.05.05 BLACKBIRD ROBOTERSYST
  • EP3102359B1 patent drawingFigure 1
  • EP3102359B1 patent drawingFigure 2a~2b
  • EP3102359B1 patent drawingFigure 2c~2d

AI summary

The invention relates to a method and a device for welding or cutting at least one workpiece (2) by means of a laser, in which a laser beam (7) is guided along a path (10) to be welded or cut in dependence on movement data of a manipulator (3), in particular an industrial robot, and a beam directing system (6) at a distance from the workpiece (2), wherein an approximating position (14) of the path is previously established offline, to improve accuracy at least the position of a reference feature (17) of the workpiece (2) is determined online by means of an optical recording system (12) in an analysis region (15), which to increase the speed of the evaluation forms a segment of a recording region (13) of the recording system (12), a target position (19) of the path is determined on the basis of the position of the reference feature (17), the approximating position (14) is compared with the target position (19) of the path and, if there are positional deviations, the path (10) is corrected. According to the invention, to increase the immunity from errors, the size, position and/or orientation of the analysis region (15) within the recording region (13) is dynamically adapted by means of the optical recording system (12), in particular in dependence on at least one offline parameter, approximately determining the position of the reference feature (17) within the recording region (13), and/or influencing online parameter.