Abstract: The invention relates to a method for connecting the ends of steel tubes by means of orbital welding using a hybrid laser arc technique, with the tubes preferably having wall thicknesses ?6 mm and more particularly ?12 mm and diameters of preferably ?150 mm, the ends of which tubes are connected by one or more welding passes, wherein the laser and arc welding heads as tools are guided over a guide ring fixedly arranged around a tube end in the region of the weld site during the welding and are displaced around the tube diameter. The invention also relates to a device for carrying out the method, wherein the laser and the arc welding heads are positioned separately on the guide ring and are moved over the tube circumference and controlled independently of one another during the welding process.

Abstract: Method for regulating the control of an electrical wastegate actuator controlled via an H bridge to permit displacement of the wastegate in its closure and opening directions according to whether the current passes through the actuator in one or opposite direction, includes: determining a set position which the wastegate has to reach, and an activation time of the actuator defining a monitoring time; applying a control signal to the actuator to displace the valve into the set position; measuring the current passing through the H bridge and applying a correction factor to the current to obtain the motor torque; obtaining the displacement speed of the wastegate by integration of the motor torque; obtaining the position reached by the wastegate at the end of the monitoring time by integration of the speed; comparing the position reached with the set position; and repeating the method until the set position is reached.

Abstract: In a method for performing a synchronized superposed operation of two servomotors, controllers for the servomotors perform the control for achieving the synchronized superposed operation by: calculating, for each of the servomotors, the difference, or differences, between the ideal speed and/or position deviations obtained from a control command and the actual speed and/or position deviations obtained from the rotation of the servomotor; calculating a speed correction quantity, or a speed correction quantity and a current correction quantity, from the discrepancy, or discrepancies, between the differences calculated for both of the servomotors; and adding the correction quantity, or quantities, to a speed command, or to a speed command and a current command, given to the subsidiary shaft side. Thus, a synchronized superposed operation of servomotors in which speeds and responses of the main shaft and the subsidiary shaft are well balanced therebetween can be achieved.

Abstract: An apparatus for feeding a bar electrode to a plasma burner wherein the electrode is advanced and rotated by a roller having its axis inclined at an acute angle relative to the surface of the electrode.