Robotic Weldhead TCP Calibration Using Multi-Camera Protrusion Sensing

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Solution Overview

Problem

Conventional robotic welding systems require manual calibration of the tool center point (TCP) in 3D space, which is time-consuming and prone to operator error due to the need for manual movement and alignment of the tool against a fixed point.

Innovation Solution

An automated method using image sensors and a controller to identify a protrusion from the weldhead, define its longitudinal axis, and calculate the TCP's location in 3D space, eliminating the need for manual intervention by guiding the robot to brush against a fixed object.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual calibration method is used, then operator can directly adjust TCP position, but calibration process is time-consuming and prone to operator error

Engineering Contradiction:
ImproveTCP calibration precisionVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical calibration operations with an automated vision-based system. Image sensors capture images of the tool, and a controller automatically processes these images to determine TCP coordinates, eliminating the need for manual mechanical adjustment and reducing both time and human error.

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

Solution Approach 2:

The system enables self-calibration by using the robot's own image sensors to capture and process images of its tool. The controller automatically identifies the protrusion, defines the longitudinal axis, and calculates TCP position without requiring external operators or additional calibration equipment.

Inventive Principle:
Principle #25Self-service

2Reliability

If manual calibration method is used, then operator can adjust TCP position, but the process is prone to operator error

Engineering Contradiction:
Improvecalibration reliabilityVSAvoidcalibration operation complexity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces manual mechanical calibration operations with an automated vision-based system. Image sensors capture images of the tool, and a controller automatically processes these images to determine TCP coordinates, eliminating the need for manual mechanical adjustment and reducing both time and human error.

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

Solution Approach 2:

The patent introduces an intermediary automated processing system between the physical tool and the TCP calibration result. The controller acts as an intermediary that objectively processes image data and calculates coordinates, removing human judgment and error from the calibration process.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If automated image-based method is used, then calibration time is reduced and precision is improved, but device complexity increases

Engineering Contradiction:
ImproveTCP calibration precisionVSAvoidcalibration system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the robot's existing image sensors multi-functional by using them both for welding process monitoring and for TCP calibration. This eliminates the need for separate dedicated calibration sensors, reducing overall system complexity while maintaining high precision.

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

Solution Approach 2:

The system enables self-calibration by using the robot's own image sensors to capture and process images of its tool. The controller automatically identifies the protrusion, defines the longitudinal axis, and calculates TCP position without requiring external operators or additional calibration equipment.

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 allows for accurate and precise calibration of the TCP in 3D space, reducing calibration time and minimizing operator error, enabling faster and more reliable robotic welding operations.

Implementation Method 1

receiving a plurality of images captured from a plurality of image sensors of the robotic welding system, the plurality of images containing at least a portion of a protrusion extending from a tip of a weldhead

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentUS20230278224A1Tool calibration for manufacturing robots
Publication Date: 2023.09.07 PATH ROBOTICS INC
  • US20230278224A1 patent drawing
  • US20230278224A1 patent drawing
  • US20230278224A1 patent drawing

AI summary

A method for calibrating a tool center point (TCP) of a robotic welding system. The method includes receiving a plurality of images captured from a plurality of image sensors of the robotic welding system, the plurality of images containing at least a portion of a protrusion extending from a tip of a weldhead of the robotic welding system, and identifying by a controller of the robotic welding system the protrusion extending from the weldhead in the plurality of images. The method additionally includes defining by the controller a longitudinal axis of the protrusion based on the protrusion identified in the plurality of images, and identifying by the controller a location in three-dimensional (3D) space of the weldhead based on the protrusion identified in the plurality of images and the defined longitudinal axis of the protrusion.