Mobile welding robot with remote center of motion

A robotic welding system for executing a welding task, the system comprising:

• a positioning device having a positioning arm;
• a welding robot for performing welding operations when engaged by the positioning arm, the welding robot comprising,
• a robot arm configured for being connected to the positioning arm at a mounting point,
• a welding gun connected to the robot arm,
• wherein an at least first remote center of motion is defined by a point on a kinematic chain along the robot arm and the positioning arm, and
• wherein the system is configured to continuously monitor the at least first remote center of motion and the tool center point during operation of the welding gun such that displacement of the positioning arm and/or the positioning device is compensated to minimize an undesired displacement of the welding gun.

A computer implemented method for controlling a welding system, having a positioning device, a first robot arm connected to the positioning device at a

• mounting point, and a welding gun connected to the robot arm, the method comprises the steps of:
• calculating coordinates of an at least first remote center of motion defined by a point on a kinematic chain along the robot arm and the positioning device,
• measuring a displacement, movement and/vibrations of the positioning device with respect to the at least first remote center of motion or to the welding robot, and
• controllably moving the positioning device and/or the robot arm such that the displacement of the positioning device is compensated to minimize an undesired displacement of the welding gun.