Research On Vision Positioning Technology Of Robot Drilling For CFRP

With the implementation of the “made in China 2025” program,the achievements of the large home-made aircraft project have been constantly emerging,including the service of Yun20 large transport aircraft,the first flight of C919 passenger aircraft and Jiaolong 600 seaplane.In aviation manufacturing,hole drilling accounts occupied more than half of the total processing work,so it is of great practical significance and application value to improve the drilling efficiency and quality.And in the current field of aviation manufacturing,carbon fiber reinforced polymer(CFRP)are gradually replacing the traditional metal materials,and it is widely used in the manufacturing of key parts such as fuselage,wing and tail.However the hole-drilling performance of carbon fiber composites is quite different from that of traditional metal materials.The application of robot automatic hole drilling and visual positioning technology in carbon fiber composites machining can effectively improve the positioning accuracy and perpendicularity accuracy,guarantee the hole drilling quality and improve the production efficiency.In this paper,a robotic automatic drilling system for CFRP processing is constructed.Based on the robot technology and machine vision technology,the hole location,surface normal acquisition,robot pose adjustment and other contents are studied.First of all,according to the research and application of robot automatic drilling technology and equipment at home and abroad,combined with the processing characteristics of CFRP and the processing requirements in aviation manufacturing,we determine the key technologies and the overall scheme of the system researched in this paper.Secondly,by using the machine vision technology,the system could identify the hole and judge the hole's position.Making the determination to the position of the hole center by hand-eye calibration and coordinate transformation,the system loaded the position information to the robot and the robot is guided to move to the prepration location for hole drilling.And then,obtaining the actual normal direction of the hole center line surface by scanning in three dimensions and fitting the curved surface of the workpiece near the hole,the system orderd robot to adjust its position and pose,so that the feed direction of the drilling tool could coincide with the normal direction of the hole center.After that,the curved surface normal adjustment of hole drilling is realized.Finally,the processing experiments are analyzed to verify the visual positioning of holes,the visual guidance of robots,the normal acquisition of curved surfaces and the adjustment of the robot position and pose.The position and verticality accuracy of holes after processing are tested to verify that the system is suitable for the holing of carbon fiber composites.