Microwave Welding Head Edge Detection via Polarization
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Solution Overview
Problem
Current radar sensors used in welding processes face challenges in accurately tracking seams due to sensitivity to perturbations and limited resolution, especially in environments with smoke, spattering, high temperatures, and electromagnetic fields, leading to blurred distance measurements and inaccurate edge detection.
Innovation Solution
The method involves using microwaves with different polarizations, where the transmitter and receiver are arranged at an angle to each other, allowing for phase change evaluation to determine the edge position, and moving the transmitter-receiver pair around the welding head to create a synthetic aperture for precise edge detection, including determining the direction and width of the gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If narrow-band continuous wave radar signals are used for distance measurement, then the system is simpler to implement, but measurement precision deteriorates due to blurred distance information and inability to achieve high spatial resolution
Solution Approach 1:
The patent changes the polarization parameter of the microwave signal to resolve the contradiction. By transmitting microwaves with different polarizations and evaluating the phase change of reflected signals, the system achieves high measurement precision without requiring complex narrow-band radar systems with expensive large antennas and additional driving units for oscillation generation.
2Area of stationary object
If the radar antenna illuminates a large area to cover the seam, then the measurement area is sufficient, but measurement precision deteriorates due to lay-over of reflections from different positions
Solution Approach 1:
The patent applies local quality by using polarization differentiation to isolate reflections from specific local positions. The transmitter and receiver are arranged at an angle to each other, and by evaluating the phase change of microwaves reflected at different positions with different polarizations, the system can distinguish edge reflections from other reflections in the illuminated area, achieving high precision edge detection despite large illumination area.
3Productivity
If continuous wave radar is used for seam tracking, then the system can operate continuously, but reliability deteriorates due to sensitivity to perturbation by undesired reflections and electromagnetic fields in welding environments
Solution Approach 1:
The patent converts the harmful effect of undesired reflections and electromagnetic field perturbations into a beneficial measurement mechanism. By arranging the transmitter and receiver at an angle and evaluating the phase change of reflected microwaves with different polarizations, the system can distinguish desired edge reflections from undesired background reflections, maintaining continuous tracking capability while improving reliability in challenging welding environments.
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 provides a perturbation-insensitive and highly accurate method for tracking seams, enabling reliable detection of edge positions and orientations, even in challenging welding environments, and allows for precise calculation of seam geometry.
Implementation Method 1
a measuring signal is sent in the form of microwaves from a transmitter arranged on the welding head to the workpiece, and the microwaves reflected on the workpiece are received by at least one receiver arranged on the welding head
Implementation Method 2
the position of the edge is determined by the evaluation module at least on the basis of a phase change of the respective microwaves reflected at the different positions
Implementation Method 3
a change of polarisation, by at least one receiver arranged on the welding head, having a polarisation plane arranged at an angle to the polarisation plane of the transmitter
Data Source
AI summary
A method for positioning a welding head or welding torch of a robot welding system over a workpiece sends microwaves as a measuring signal from a transmitter arranged on the welding head to the workpiece. The microwaves reflected on the workpiece are received by at least one receiver arranged on the welding head, and the received microwaves are evaluated by an evaluation module for determining the position of a workpiece edge. The microwaves are sent from at least one transmitter in different positions on the welding head, and the reflected microwaves are received, with a change of polarization, by the at least one receiver, having a polarization plane arranged at an angle to the polarization plane of the transmitter. The position of the edge is determined by the evaluation module at least on the basis of a phase change of the respective microwaves reflected on the different positions.