Research and implementation of steel barrel cover rotation correction

Given the problems of low efficiency and poor accuracy of manual adjustment of offset position in screen printing of steel barrel cover, an automatic correction method based on machine vision is studied. The mode of upper-lower computers is adopted. For barrel cover with screw holes, Hough circle detection determines the number and position of screw holes and calculates the rotation direction and angle based on the big screw holes as the orientation datum. For barrel cover without screw holes, which is characterized by a steel seal, a minimum area rectangle is adopted to calculate the rotation direction and angle by collecting the location parameters of the width of the rectangle. The lower computer, PLC, controls the servo motor rotation and exchanges data through the Modbus TCP protocol. The results show that the method can adapt to the characteristics of the screw holes and the steel seal. The rotation angle is within (−180°, 180°). The angular error was ± 0.50°. The method meets the requirements of accuracy and stability.