Method for positioning a tool holder on a workpiece, comprises positioning a tool on the workpiece holder under use of a drive unit driven by a sensor-less motor, by moving the workpiece holder relative to workpiece

摘要

The method for positioning a tool holder (80) for forming-technical joining process such as clinching and punch riveting, and/or for thermal joining process such as resistance spot welding, resistance pressure welding, handling process, imprinting process or screwing or pressing process, on a workpiece, comprises positioning a tool (30, 35) on the workpiece holder under use of a drive unit (50, 60) driven by a sensor-less motor (70), by moving the workpiece holder relative to workpiece. The drive unit is moved in the frame of the positioning between an upper dead point and a lower dead point. The method for positioning a tool holder (80) for forming-technical joining process such as clinching and punch riveting, and/or for thermal joining process such as resistance spot welding, resistance pressure welding, handling process, imprinting process or screwing or pressing process, on a workpiece, comprises positioning a tool (30, 35) on the workpiece holder under use of a drive unit (50, 60) driven by a sensor-less motor (70), by moving the workpiece holder relative to workpiece. The drive unit is moved in the frame of the positioning between an upper dead point and a lower dead point by the motor. The motor is operatable by a field-oriented regulation. The position of the rotor of the motor is determined by the field-oriented regulation. The actual tool holder position is diverted from the rotor position. The motor is operated in the operation like moments control, where a desired rotating moment is given for controlling without the actual rotating movement is considered during initial operation of the tool holder. A test signal is brought to inlet of a current regulator during the initial operation of the tool holder, where the test signal causes a control deviation. A manipulated variable for the stimulation of the motor is detected based on control deviation. The initial rotor position is determined under use of the test signal. The commutation is carried out under consideration of the determined rotor position. The tool holder comprises a position sensor by which the relative position of the tool holder is determined against the horizontal. The holding moment is detected to stop the tool holder in position under consideration of the relative position and is provided as desired rotating moment of the moment control. An acceleration moment is determined under consideration of the stop moment and the acceleration. Means for power measurement is arranged to the tool holder, whose measuring signals are considered in the positioning of the tool holder. An independent claim is included for an arrangement for positioning a tool holder on a workpiece.