Pressure control method of friction stir welding system of parallel-serial robot

The invention discloses a pressure control method of a friction stir welding system of a parallel-serial robot. The method comprises the following steps that equipment and a welding part are mounted;the welding speed of the robot is set; man-machine interaction software is started up, and communication with a hydraulic pump station is set up; the robot is inched so that a main shaft can get closeto the welding part; the spindle is started to rotate, and the rotating speed is set; the robot is inched so that the main shaft can be in contact with the welding part, and the pressure of the mainshaft is set through the hydraulic pump station; the welding track is obtained through a teaching method and is written into a motion program; the welding motion program is operated, the robot carriesout welding, and welding process parameters are uploaded to a robot control system; welding is finished, the main shaft is shut off, and the robot is moved to the zero position; and welding parameters are preserved. In the pres