Welding Robot Wire-Touch Sensing for Collision-Free Teaching

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Solution Overview

Problem

Current methods for programming welding robots, such as teach-in and playback processes, often result in collisions between the welding wire or head and the workpiece during the teaching or checking of movement sequences, leading to potential damage and inefficiencies due to the lack of real-time feedback on the wire's position relative to the workpiece.

Innovation Solution

A method involving a 'wire-touch sensing process' where a test voltage is applied between the welding wire and the workpiece, allowing for detection of current flow or voltage drops, which triggers the retraction of the welding wire to prevent collisions, and the use of this process to scan the workpiece contour and determine precise positions, ensuring safe and accurate movement sequences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the welding wire is extended to a fixed length without real-time position monitoring, then the teaching process is simpler, but collisions between the welding wire and workpiece occur leading to damage and inefficiency

Engineering Contradiction:
Improveteaching process simplicityVSAvoidcollision prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements a feedback mechanism by applying test voltage between the welding wire and workpiece to detect current flow. When contact is detected, the system provides real-time feedback to retract the welding wire, preventing collisions and damage while maintaining teaching process simplicity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces mechanical position monitoring systems with an electrical detection system. Instead of using complex mechanical sensors to monitor wire position, the system uses electrical conductivity detection through test voltage application to sense wire-contact conditions, simplifying the system while improving reliability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If the welding head is moved quickly to teach positions, then productivity increases, but the risk of collision and damage increases

Engineering Contradiction:
Improveteaching speedVSAvoidcollision damage risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by proactively detecting potential collisions through test voltage application before actual contact occurs. The system continuously monitors for contact conditions and preemptively retracts the welding wire when contact is detected, counteracting the harmful effects of high-speed movement

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The real-time electrical feedback system allows the welding head to move quickly during teaching while maintaining safety. The feedback mechanism detects contact conditions instantaneously, enabling high-speed operation without increasing collision damage risk

Inventive Principle:
Principle #23Feedback

3Device complexity

If manual positioning is performed without real-time contact detection, then the equipment complexity is reduced, but positioning precision and safety deteriorate

Engineering Contradiction:
Improveequipment simplicityVSAvoidpositioning accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent implements a simple yet effective feedback mechanism using test voltage application. This electrical feedback provides real-time contact detection that enhances positioning precision without adding complex mechanical sensing equipment, maintaining equipment simplicity while improving accuracy

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent substitutes complex mechanical position sensing systems with a simple electrical detection system. By using test voltage and current flow detection, the system achieves precise contact detection and positioning accuracy while keeping the equipment simple and easy to implement

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 effectively prevents collisions and damage by quickly retracting the welding wire and head, allowing for precise positioning and accurate teaching of movement sequences, reducing the risk of material loss and increasing operational efficiency.

Implementation Method 1

a test voltage is applied between the welding wire and the workpiece, allowing for detection of current flow or voltage drops

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2663417B1Method of teaching / checking a sequence of movement of a welding robot, welding robot and associated controller
Publication Date: 2018.10.31 FRONIUS INT GMBH
  • EP2663417B1 patent drawingFigure 1
  • EP2663417B1 patent drawingFigure 2~3
  • EP2663417B1 patent drawingFigure 4~9

AI summary

The invention relates to a method for teaching a welding robot, in which a position is determined and stored by way of a manually implemented positioning process. In a first step, a movably mounted welding wire (9, 30) is moved to a length (1) out of a welding head (20). The welding head (29) is then moved to a position at a workpiece (14, 31). After being positioned, a wire-touch sensing process is started in the welding apparatus, in which a test voltage is applied between the welding wire (9, 30) and the workpiece (14, 31) and subsequently the manual positioning process with the welding head (29) is continued. The welding wire (9, 30) is retracted to interrupt the current flow whenever a current flow between the welding wire (9, 30) and the workpiece (14, 31) or a drop in the test voltage is detected. Furthermore, a welding system and/or a control system for same are specified, which carry out the method according to the invention.