Rapid Identification And Location Technology Of Reference Hole In Automatic Drilling Based On Differential Edge Detection

In the aircraft assembly process,the quality of the connection holes between the components of the aircraft is of great importance for the safety and service life of the aircraft.Because of the large number of connecting holes on the large aircraft, the accuracy and efficiency of manual drilling methods cannot meet the requirements of modern aircraft assembly process. Regarding to this problem,aircraft manufacturers at home and abroad have developed a variety of automated drilling equipment for digital aircraft assembly . In order to improve the position accuracy of the automatic drilling process, the automated drilling system is usually integrated with vision-based measuring unit. This unit measures and corrects the drilling position of the fitting hole according to the deviation between the actual position and the theoretical position of the reference hole. Whether the reference hole can be identified correctly and quickly is vital for the process. In that context, focusing on the problem of identification andlocation of the reference hole,we propose a new edge detection method in this paper,correspondingly, an algorithm for automatic reference hole identification and location is proposed. The main contents and innovations of this paper are as follows:First of all,the research background of the subject is clarified. At home and abroad,the present research situation of aircraft digital assembly technology and visual measurement technology are reviewed, and the latest research results of edge detection theory are studied. The research object and research contents of this paper are elicited.Secondly, the system structure, control method and control software of the automatic drilling system are studied. The system kinematics is modeled and analyzed. The composition and measurement method of the visual measurement unit are summarized.Thirdly,a new edge detection method based on differential edge detection is proposed,and the detailed process of edge detection is introduced in the process of edge detection. The method of image detection is used to verify the edge recognition ability of the image and to lay a foundation for fast identification of the reference hole.Finally, based on the new edge detection method, a fast identification algorithm of the reference hole is proposed, and the efficiency of the algorithm is analyzed. The reference hole identification experiment was carried out and compared to similar algorithms. The hole positioning precision test is also conducted. It is proved that the reference hole image can be precisely identified by the algorithm and the reference hole information can be obtained. Thus the high-precision identification and location of the reference hole in the automatic drilling system are realized. This is a reliable method for rapid identification and location of reference holes in automatic drilling.