Weld Line Detection Using Angled Contactor for Industrial Robots

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Solution Overview

Problem

Conventional weld line-detecting methods for industrial robots during fillet welding are prone to operation errors, sensor damage from high-temperature molten metal, and lack a mechanism to release the welding torch's pressed state, leading to incorrect welding positions and potential equipment damage.

Innovation Solution

A weld line-detecting method that uses an angle sensor with a contactor attached to the welding torch, transmitting angle information to the robot, and moving the torch to zero out the contactor's angle, allowing for precise detection and release of the welding position, with mode switching to prevent sensor damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sensor is disposed in the welding torch to detect welding position, then welding position detection capability is improved, but the sensor is exposed to high-temperature molten metal that can damage it

Engineering Contradiction:

Improvewelding position detectionVSAvoidsensor durability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a contactor as an intermediary component that physically contacts the workpiece to detect welding position, while the sensor remains protected inside the welding torch. The contactor transmits mechanical contact information to the sensor without exposing the sensor directly to the harsh welding environment and molten metal

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the conventional force sensor that directly measures bending moment with a contactor-based mechanical contact detection system. The contactor's physical contact with the workpiece generates detectable signals without requiring the sensor to be exposed to high-temperature environments

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If the welding torch is pressed against the workpiece to detect welding position, then position detection is achieved, but the welding wire projection length becomes shorter than required

Engineering Contradiction:

Improvewelding position detectionVSAvoidwelding wire projection length

Core Design Contradiction:

Measurement precisionVSLength of moving object

Solution Approach 1:

The patent separates the detection function from the welding function by introducing a dedicated contactor for position detection. This allows the welding torch to maintain its proper welding configuration with adequate wire projection length while the contactor independently performs position detection through mechanical contact

Inventive Principle:

Principle #1Segmentation

3Extent of automation

If the welding robot automatically operates the welding torch based on bending moment detection, then automation is improved, but operation errors can cause the welding core to be firmly pressed into the welding object

Engineering Contradiction:

Improveautomatic welding torch operationVSAvoidequipment safety

Core Design Contradiction:

Extent of automationVSReliability

Solution Approach 1:

The patent implements feedback control by continuously monitoring contactor contact status and providing real-time information to the robot control system. This feedback mechanism allows the system to detect welding position and adjust operations automatically while preventing excessive pressing forces that could damage equipment

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent enables dynamic switching between manual and automatic operation modes, allowing the system to adapt its control strategy based on operational requirements. This dynamic capability ensures safe automatic operation while maintaining operator control when needed

Inventive Principle:

Principle #15Dynamics

4Loss of information

If electric wires are used to transmit signals from the sensor, then signal transmission is achieved, but the electric wire is exposed to molten metal that can damage it

Engineering Contradiction:

Improvesignal transmissionVSAvoidelectric wire durability

Core Design Contradiction:

Loss of informationVSReliability

Solution Approach 1:

The contactor serves as a protective intermediary that transmits mechanical contact information to the sensor system without requiring electric wires to extend to the contact point. This eliminates direct wire exposure to molten metal while maintaining signal transmission capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10105784B2Weld line-detecting method and industrial robot

Publication Date: 2018.10.23 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

The present invention is a weld line-detecting method when fillet welding by an industrial robot including a welding torch is taught. The welding torch on which an angle sensor having a contactor is attached is moved toward a welding object, angle information obtained when the contactor is in contact with the welding object is transmitted to the industrial robot, and the industrial robot moves the welding torch based on the angle information so that the angle of the contactor becomes zero. These operations are repeated, and the welding torch is moved toward a fillet part along the surface of the welding object. When the contactor arrives at the fillet part, a signal indicating that the contactor is pressed in the axial direction of the contactor is transmitted to the industrial robot. The industrial robot detects that the contactor arrives at the position to be welded on the weld line.