Simulation of robotic TIG-welding

Sammanfattning: Robotised welding is one of the most important robot tasks used in manufacturing industry. The operator usually performs the programming of the robot manually, i.e. by jogging the robot arm to each coordinate pose in space. Programming can, however, be made more accurate by the use of simulation, using so called Computer Aided Robotics. Simulation can also be a powerful tool to evaluate and control welding heat effects, such as unwanted stresses and deformation. The objective of this thesis was to develop a simulation tool and a method by which robot trajectories, temperature histories, residual stresses and distortion can be analysed and optimised off-line. This was performed by integrating robot simulation software with finite element analysis software. A special interface was created allowing information exchange between the two software programs. The method was used to program welding trajectories both for planar plates and for a part of an aerospace component. The trajectories was downloaded to the finite element analysis software where temperature and residual stress prediction were performed. Good agreement was found between the programmed robot trajectory, and the actual trajectory and only small adjustments were necessary. Temperature measurements were performed using both thermocouples and infrared imaging. Good agreement was also found between the results using these two methods. The method developed provides a powerful tool to construct and optimise robot trajectories and welding process parameters off-line.