The aim of the proposed project is the development of an arc sensored seam tracking system. The arc sensored seam tracking system will provide the following features.
Main result of the project is an arc-sensing system with the following benefits:
- No external sensors required, thus maximum reachability of the weld
- Correction of thermal distortion, tolerances and displacement of the workpiece
- Capability of adaptation of torch orientation in 2 or 3 dimensions for continuous seams
- Automatic welding of seams with sharp corners
- saving of programming time as only start and end point must be taught
- Reduction of economic batch size for robotic arc welding because of reduced programming time. The advantages of automatic welding such as higher and constant quality and a better working environment may so be applied to a larger range of welding workpieces.
The systems performance is limited because of the low signal quality and sampling rate of the arc-sensing principles used at present (oscillation across groove with oscillation frequencies <= 5 Hz) and the low communication speed between the sensing unit and the robot controllers (approximately 200 ms per cycle)
Resulting from the project there are some spin-offs also of considerable benefits to European metalworking industry.
- An arc-sensing system capable of correcting both height and side displacements of the torch without being affected by the changing of welding parameters but with all advantages of existing systems.
This system is a lot easier to use than existing systems and allows a faster set-up of automatic welding machines, thus saving set-up time and testing workpieces and reducing costs.
- A new technique to obtain arc signals of higher quality and at a higher sampling rate.
Together with faster robot controllers as they are being introduced in the mean time, this system may help to extend the developed arc sensing systems capabilities and minimise its limitations.
The arc sensored seam tracking system will provide the following features:
-automatic height and side adjustment of the torch
-automatic adaptation of the torch orientation to the actual seam direction in 3 dimensions
-weldability of closed seams (orientation adjustment angle > 360 degrees)
-welding speed is not affected by seam deviation
-automatic adaptation of welding and oscillation parameters for out-of-position welding
-weldability of continuous curved seams (with a certain radius, smallest possible, e.g. 20 mm) and non-continuous curved seams (sharp corners)
-reduction of seam programming to the teaching of start and final point.