Typical systems for automated welding, or automated manufacturing processes in general, are only able to follow predefined motions, which makes them inflexible and puts a lot of importance on proper joint preparation. The use of sensors can be implemented to modify the machine’s path, but there are limitations for which procedures they can be applied to, and a predefine motion is still required.

The system that is developed here will be capable of generating a path for the machine to follow in real-time, to be implemented in welding systems to account for imperfections on the workpiece and sudden movements during welding.

This system is comprised of two parts; a PLC program that manages the movement produced by two servo motors and a client program that calculates the path the machine should follow and supplies the PLC with coordinates to follow.

Due to the complexity caused by the need to synchronize the PLC program to the client, we had to develop a methodology for writing the PLC program that could simplify the implementation of the logic. The PLC program was made by implementing a state machine in structured text with an object oriented approach.

This system was tested with a pair of servo motors, by having the client generate a path in the shape of a sinusoidal wave for the motors to follow while reading the motor’s positions. After running the test, it was found that this system is capable of following the path it is given with a good degree of accuracy. This system is capable of following a path with less than 2% deviation. This may get worse as the velocityof the system increases, or if the path becomes irregular.