Method for field-operation calibration of industrial robot based on 3D vision

Industrial robot plays an irreplaceable role in various industries of modern manufacturing, such as automotive, logistics, heavy industry, and electronics. Industrial six-axis robot, as a multi-joint serial mechanism, has relatively low absolute positioning accuracy due to errors in the manufacturing and assembly process, which cannot meet the increasingly precise operation scenarios. Field-operation calibration is necessary to improve their absolute positioning accuracy. Traditional calibration methods mainly rely on high-precision external measurement equipment such as laser tracker, but such equipment is expensive, and considering the transportation time, the timeliness of field-operation calibration cannot be guaranteed. This paper proposes a method for industrial robot calibration based on 3D vision. The robot carries a standard ball and moves to multiple positions within the field of view of the 3D vision sensor, which can complete the robot calibration. The experimental results show that: after calibration, the absolute positioning error of the robot is reduced by 65%, when the calibration results are applied to vision-guided grasping, the vision positioning error is reduced by 30%, and the robot grasping error is reduced by 33%. Moreover, this method does not require the assistance of additional high-precision measurement equipment, and it has low cost and good timeliness.