Welding Tongs Position Control With Bending-Compensated Displacement

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Solution Overview

Problem

Conventional resistance welding systems face challenges in maintaining consistent quality of weld spots, especially with new material thickness combinations, due to limitations in force regulation and path signal detection, which affects the process window and weldability.

Innovation Solution

A device and method for position control of pliers-shaped tools that compensates for mechanical bending and force variations by generating a standardized path signal, allowing for targeted force regulation and improved monitoring of the welding process, enabling consistent quality across different material combinations and tool configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sensor is attached to the movable clamping arm to detect position signal, then position control is achieved, but the displacement signal depends on mechanical configuration and bending, requiring complex recording for each configuration

Engineering Contradiction:
Improveposition signal detectionVSAvoidcomplex recording of mechanical configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A magnetic field sensor detects the position of a magnetic marker on the stationary clamping arm, providing an intermediary measurement method that is independent of the movable arm's mechanical configuration and bending, thus resolving the contradiction between position detection accuracy and system complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mechanical configuration-dependent displacement measurement is replaced by a magnetic field-based position detection system, eliminating the need for complex mechanical recording while achieving accurate position control

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

2Manufacturing precision

If force regulation is used to control welding process, then welding quality is maintained, but the process window narrows with new material thickness combinations

Engineering Contradiction:
Improvewelding quality consistencyVSAvoidprocess window for different material combinations
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The control system dynamically adjusts both force and position parameters based on real-time feedback from sensors, allowing adaptation to different material thickness combinations while maintaining welding quality consistency, thus expanding the process window

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes control parameters from force-only regulation to combined force and position regulation, enabling adaptation to various material combinations and expanding the viable process window while maintaining manufacturing precision

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If sensor position is optimized for displacement detection, then detection accuracy is improved, but the weld cannot be created due to sensor interference

Engineering Contradiction:
Improvedisplacement signal detectionVSAvoidweld creation
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A magnetic field serves as an intermediary for position detection, allowing the sensor to be positioned away from the welding zone while still accurately detecting the position of the magnetic marker, thus eliminating interference with weld creation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Mechanical contact-based displacement detection is replaced by magnetic field-based detection, allowing non-contact measurement that does not interfere with the welding process while maintaining detection accuracy

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

Data Source

PatentEP4382247A1Device and method for adjusting the position of a plier-shaped tool
Publication Date: 2024.06.12 ROBERT BOSCH GMBH
  • EP4382247A1 patent drawingFigure 1~2
  • EP4382247A1 patent drawingFigure 3~4
  • EP4382247A1 patent drawingFigure 5~6

AI summary

A control device (10) for a welding tool (21) and a method for position control of a welding tool (21; 210; 2100) are provided. The control device (10) has a determination module (11) for determining a normalized displacement signal (Sn(t)) in which a bending of the pincer-shaped tool (21; 210; 2100) is compensated, which is generated by the action of a mechanical force (Fs(t)) on the tool (21; 210; 2100) during a work operation (S2, S3, S4; S5; S8; S13; S17; S20) with the pincer-shaped tool (21; 210; 2100), and a force control module (12) for controlling a curve of the force (Fs(t)) which the pincer-shaped tool (21; 210; 2100) exerts on at least one component (5, 6) during the work operation (S2, S3, S4; S5; S8; S13; S17; S20). exerts, wherein the force control module (12) is designed to control the course of the force (Fs(t)) during the work process (S8; S13; S17; S20) using the normalized displacement signal (Sn(t)).