Abstract: A welding robot having a robot arm which is servo-controlled in a multiplicity of degrees of freedom. At least one servo-system for one of the degrees of freedom is capable of disengaging a part of its feedback network, this part being an integrating circuit, whereby the adjustment from PI-type passes to P-type. The arm then becomes sprung in a direction away for a set-point value with respect to this freedom of movement. When used for welding, the welding gun used and attached to the robot arm is provided with a holding-off or fender arrangement, such as wheels, and is drawn by the servo-system towards a set-point value which it is unable to attain because of the shape of the workpiece, whereupon the wheel is caused to press against the workpiece with spring force, and to follow the shape of a weld joint as it is made, irrespective of whether the joint is uneven or not.