In the automated welding technology on three dimensional constructions, the welding
tools will be proceed along the components of programmed handling systems in order
to weld the components with each other. Tolerances while manufacturing result in the
joints being able to be found at different positions. The deviations from the correct way
are registered with the aid of sensors and transformed in control data for regulation of
deviation. For this purpose, different models were developed by sensors which are
mounted firmly in front of the welding tool and in such a way that it can recognize the
deviations. In this case, the freedom of movement of the handling systems is limited at
one degree of freedom. Abrupt direction changes lead to measurement errors so that the
sensor leaves the measuring range.
For this reason a new optical sensor was developed in this that is able to detect all
necessary work parameters while welding. The sensor is based on the purposeful
evaluation of structured illuminated projections around the welding point. The
structured light occurs with a holographic projection system. An adapted preprocessing
of data as well as a optimised rule-based recognition of the joint direction make also
possible to detect complex welding joints in real time. The seam tracking system
determines the position of the joint to be welded in the working area, the deviation of
the welding head from the normal at the surface as well as the width of the gap between
the components with a solution of 50 !Jm. The optical, mechanical, electronical and
data processing components were developed for the high orders while welding with the
laser. The use of this new seam tracking sensor allows the use of handling systems with
only five axes at three dimensional joint geometries.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.