Welding Force Validation Using Tool-Model Plausibility Checks

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Solution Overview

Problem

Existing welding control systems face challenges in ensuring consistent quality of welds due to incorrect force measurements from defective or miscontrolled force sensors, leading to issues like poor spot weld quality and damage to welding tools.

Innovation Solution

A device with a determination module to calculate an expected force value based on a model of the welding tool and a comparison module to verify actual force values, allowing for the detection of incorrect measurements and adjustment of forces to prevent damage and maintain quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a force sensor is used to measure actual force values for controlling the welding tool, then force control capability is improved, but measurement reliability deteriorates due to sensor defects or incorrect control

Engineering Contradiction:
Improveforce control capabilityVSAvoidmeasurement reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A determination module is introduced as an intermediary that calculates an expected force value based on a welding tool model and compares it with the actual force value from the sensor. This intermediary verification mechanism detects discrepancies caused by sensor defects before they affect welding quality, resolving the contradiction between maintaining force control capability and ensuring measurement reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If incorrect actual force values are used to control the welding tool, then welding quality deteriorates, but the cost of implementing verification systems increases

Engineering Contradiction:
Improvewelding qualityVSAvoidverification system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system implements a feedback mechanism where the determination module continuously compares expected force values (calculated from welding parameters and tool model) with actual sensor measurements. When discrepancies exceed a threshold, the system alerts the operator or adjusts control parameters, preventing poor welding quality without requiring complex additional hardware.

Inventive Principle:
Principle #23Feedback

3Device complexity

If force sensor values are not verified, then device complexity is reduced, but tool damage risk increases

Engineering Contradiction:
Improvecontrol system complexityVSAvoidtool damage risk
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The determination module performs preliminary verification of force sensor values before the welding operation proceeds. By calculating expected force values based on the welding tool model and comparing them with actual measurements in advance, the system prevents tool damage from incorrect force application without adding complex real-time intervention mechanisms.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3854510B1Welding control device and method for validating force values in the control of a welding tool
Publication Date: 2024.02.07 ROBERT BOSCH GMBH
  • EP3854510B1 patent drawingFigure 1
  • EP3854510B1 patent drawingFigure 2~3
  • EP3854510B1 patent drawingFigure 4~5

AI summary

A device (50; 50A; 50B) for a welding control (10) and a method for verifying the plausibility of force values ​​when controlling a welding tool (21) are provided.The device (50; 50A; 50B) has a determination module (51) for determining an expected value (LE, IE, ME) of a physical quantity that occurs during a welding process with a welding tool (21) and depends on a force (FS(t); FS_ACT) exerted by at least one electrode (22, 23) of the welding tool (21) on at least one component (5, 6) when producing a weld joint (7), and a comparison module (52) for comparing the expected value (LE, IE, ME) with an actual value (LACT, In_ACT, Mn_ACT) of the physical quantity that occurs during the welding process with the welding tool (21) in order to verify an actual value of the force (Fs(t); FS_ACT) recorded during the welding process with the welding tool (21), wherein the determination module (51) is configured to determine the expected value (LE, IE, ME) to determine with a model (511) of the welding tool (21).