3D Welding Torch Orientation Tracking With IMU Drift Compensation

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Solution Overview

Problem

Manual arc welding processes face challenges in achieving high-quality welds due to the difficulty in maintaining optimal torch orientation, which is dependent on the welder's skill level and physiological conditions, leading to lengthy training cycles and inconsistent weld quality.

Innovation Solution

A method utilizing a miniature inertial measurement unit (IMU) with a quaternion-based unscented Kalman filter and an auto-nulling algorithm to accurately measure and compensate for gyro drift, enabling real-time feedback and adjustment of torch orientation during welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a welder relies on skill level and physiological conditions to maintain torch orientation, then ease of operation is improved, but manufacturing precision and reliability deteriorate due to inconsistent weld quality and lengthy training cycles

Engineering Contradiction:
Improvetorch manipulationVSAvoidtorch orientation accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent implements real-time feedback through an inertial measurement unit (IMU) that continuously monitors torch orientation and provides immediate feedback to the welder. This allows the welder to maintain proper torch orientation through intuitive adjustments based on visual or haptic feedback, eliminating the need for lengthy training while ensuring consistent weld quality. The feedback loop transforms subjective skill-based manipulation into an objective, guided process.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces the reliance on human skill and physiological condition with an electronic sensing and feedback system. The IMU device with accelerometers and gyroscopes substitutes for the welder's internal sense of orientation, providing objective measurement and guidance. This substitution maintains ease of operation while dramatically improving manufacturing precision and reliability.

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

2Device complexity

If torch orientation is manually controlled without real-time measurement, then device complexity is reduced, but measurement precision and reliability deteriorate

Engineering Contradiction:
Improvemeasurement systemVSAvoidtorch orientation measurement
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the measurement function into a separate, portable IMU device that attaches to the torch. This segmentation allows the measurement system to be added without complicating the core welding equipment. The IMU contains segmented components (accelerometers, gyroscopes, processor) that work together to provide precise orientation measurement while keeping the overall system modular and manageable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary IMU device that mediates between the torch and the welding process. This intermediary contains the complex measurement and processing electronics, isolating the complexity from both the torch and the welder. The IMU processes sensor data through algorithms (including complementary filters and Kalman filters) to derive accurate orientation information without requiring complex integration into the welding system itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If real-time torch orientation measurement is implemented, then manufacturing precision and reliability are improved, but device complexity and cost increase

Engineering Contradiction:
Improveweld quality consistencyVSAvoidmeasurement and feedback system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent designs the IMU device to perform multiple functions: measuring torch orientation, providing real-time feedback, guiding welder training, and potentially controlling automated welding systems. This multi-functionality justifies the added complexity by providing comprehensive value across different welding scenarios. The same hardware platform serves beginners, experienced welders, and training programs, maximizing return on investment.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The IMU device is designed to be self-contained with its own processor, sensors, power supply, and feedback mechanisms. It independently measures orientation, processes data through calibration and filtering algorithms, and provides feedback without requiring external complex systems. This self-service capability reduces overall system complexity while maintaining high measurement precision and reliability.

Inventive Principle:
Principle #25Self-service

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 significantly improves the accuracy of torch orientation measurement, reducing training time and ensuring consistent weld quality by providing instant performance feedback and laying the groundwork for intelligent welding robots.

Implementation Method 1

determining a gravitational acceleration vector... during a time interval in which the inertial measurement unit is known to be in quasi-static equilibrium

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 2

receives a first set of gyroscope output samples from an inertial measurement unit affixed to a welding torch

Methodology Applied
Scientific EffectGyroscope: Gyroscope

Data Source

PatentEP3243040B1Measurement of three-dimensional welding torch orientation for manual arc welding process
Publication Date: 2025.04.02 UNIVERSITY OF KENTUCKY RESEARCH FOUNDATION
  • EP3243040B1 patent drawingFigure 1(A)~1(D)
  • EP3243040B1 patent drawingFigure 2(A)~2(D)
  • EP3243040B1 patent drawingFigure 3A~3B

AI summary

Methods and systems are provided herein for measuring 3D apparatus (e.g., manual tool or tool accessory) orientation. Example implementations use an auto-nulling algorithm that incorporates a quaternion-based unscented Kalman filter. Example implementations use a miniature inertial measurement unit endowed with a tri-axis gyro and a tri-axis accelerometer. The auto-nulling algorithm serves as an in-line calibration procedure to compensate for the gyro drift, which has been verified to significantly improve the estimation accuracy in three-dimensions, especially in the heading estimation.