Method and control system for the calibration of a handling apparatus

A method for referencing, calibrating, or initializing a parallel kinematic robot (24), with a tool head (28) suspended from at least two parallel-kinematically movable arms (26), which tool head (28) has a movable drive connection and with a length-variably or articulately movable cardan shaft (30) between a stationary drive motor (44) and the tool head (28), which is movable about at least one rotational axis,

• wherein each of the at least two arms (26) comprises an upper arm (36), which is motor-movable between two end positions about a defined upper-arm swivel axis (38), as well as also comprising a lower arm (40), which is mounted swivelably movable on the upper arm (36),
• and wherein the arms (26) hold the tool head (28), which is movably suspended from the at least two lower arms (40), and which is movable within a defined movement range by program-controlled and mutually coordinated swivel movements of the upper arms (36) as well as of the thereby guided lower arms (40), the method comprising:
• adjusting, in each instance, the corresponding angular positions of the at least two upper arms (36) by the motor drives (42) in a first method step of detecting the load torques acting on the upper-arm swivel axes (38) and of comparing the particular load torques acting on the at least two upper arms (36) or detecting of signals from position sensors or angle sensors,
• moving the at least two upper arms (36) in a second method step by simultaneous or approximately synchronous swiveling about their particular swivel axes (38) up to a limit position, which is defined by a mechanical stop of the drive connection to the tool head (28), which drive connection is movable independently of the upper arms (36), and whereupon
• distancing the tool head (28) or the drive connection assigned thereto in a third method step by a defined swivel angle from the limit position by a return movement of the at least two upper arms (36),
• whereby the adjusted angular positions of the at least two upper arms (36) in each instance have defined difference angles to the two end positions or define a situation of the tool head (28) located within a defined distance to a central position within the movement range,
• moving a first of the at least two upper arms (36) into one of the two end positions in a further or fourth method step by motorized swiveling about the particular upper-arm swivel axis (38);
• and the angular position reached in this connection is sensor-detected and used for the position initialization or angle initialization of the first upper arm (36), whereupon the first upper arm (36) is returned from its end position into a defined angular position or into the previously assumed initial angular position,
• moving a second of the at least two upper arms (36) into one of its two end positions in a subsequent further or fifth method step by motorized swiveling about the particular upper-arm swivel axis (38) with the end position also having been selected in the previous or fourth method step;
• and the angular position reached in this connection is sensor-detected and used for the position initialization or angle initialization of the second upper arm (36), whereupon the second upper arm (36) is returned from its end position into a defined angular position or into the previously assumed initial angular position,
• wherein detecting of the particular load torques is performed in a single step or repeatedly at defined intervals during the carrying out of the second or third or fourth method steps and during the corresponding motorized movements of the upper arms (36);
• and
• wherein an exceeding of a specified difference value for successive torque values is identified as a mechanical stop or an end stop for the particular relevant upper arm (36).