The invention discloses an automatic butt assembling method for a large part as well as a
system. The method comprises steps as follows: kinematic parameters of a
servo posture adjusting positioner under the loading condition are calibrated firstly, an actual
mathematical model of a butt part is established according to measurement data of the butt part, the butt part is corrected or reworked through comparison of the actual
mathematical model and an ideal
mathematical model of the butt part, then the relative position between a butt feature point of the butt part and a support
measurement point arranged on a support device is calibrated, the butt part is mounted on the
servo posture adjusting positioner, the position of the butt part in an overall reference coordinate
system is determined, then a path of the butt part is planned with the optimum matching
algorithm, the driving amount of each shaft of the
servo posture adjusting positioner is obtained through inverse solution, finally, the butt part is moved by the servo posture adjusting positioner, and butt
assembly of the butt part is completed. According to the automatic butt assembling method for the large part as well as the
system, transfer errors are reduced, and errors caused by utilization of the ideal mathematical model or non-measurable property of the butt feature point are avoided, so that the quality and the success rate of automatic
assembly are guaranteed.